diff mbox

[v5,1/7] drm: sunxi: Add a basic DRM driver for Allwinner DE2

Message ID 8afc5e020c5767face34fe3a9ab300ce9e67ba00.1477142934.git.moinejf@free.fr (mailing list archive)
State New, archived
Headers show

Commit Message

Jean-Francois Moine Oct. 21, 2016, 7:26 a.m. UTC
Allwinner's recent SoCs, as A64, A83T and H3, contain a new display
engine, DE2.
This patch adds a DRM video driver for this device.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
---
 .../bindings/display/sunxi/sunxi-de2.txt           |  83 +++
 drivers/gpu/drm/Kconfig                            |   2 +
 drivers/gpu/drm/Makefile                           |   1 +
 drivers/gpu/drm/sunxi/Kconfig                      |  21 +
 drivers/gpu/drm/sunxi/Makefile                     |   7 +
 drivers/gpu/drm/sunxi/de2_crtc.c                   | 475 +++++++++++++++++
 drivers/gpu/drm/sunxi/de2_crtc.h                   |  63 +++
 drivers/gpu/drm/sunxi/de2_de.c                     | 591 +++++++++++++++++++++
 drivers/gpu/drm/sunxi/de2_drm.h                    |  47 ++
 drivers/gpu/drm/sunxi/de2_drv.c                    | 378 +++++++++++++
 drivers/gpu/drm/sunxi/de2_plane.c                  | 119 +++++
 11 files changed, 1787 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
 create mode 100644 drivers/gpu/drm/sunxi/Kconfig
 create mode 100644 drivers/gpu/drm/sunxi/Makefile
 create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.c
 create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.h
 create mode 100644 drivers/gpu/drm/sunxi/de2_de.c
 create mode 100644 drivers/gpu/drm/sunxi/de2_drm.h
 create mode 100644 drivers/gpu/drm/sunxi/de2_drv.c
 create mode 100644 drivers/gpu/drm/sunxi/de2_plane.c

Comments

Maxime Ripard Oct. 24, 2016, 2:04 p.m. UTC | #1
Hi,

On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
> Allwinner's recent SoCs, as A64, A83T and H3, contain a new display
> engine, DE2.
> This patch adds a DRM video driver for this device.
> 
> Signed-off-by: Jean-Francois Moine <moinejf@free.fr>

Output from checkpatch:
total: 0 errors, 20 warnings, 83 checks, 1799 lines checked

> ---
>  .../bindings/display/sunxi/sunxi-de2.txt           |  83 +++
>  drivers/gpu/drm/Kconfig                            |   2 +
>  drivers/gpu/drm/Makefile                           |   1 +
>  drivers/gpu/drm/sunxi/Kconfig                      |  21 +
>  drivers/gpu/drm/sunxi/Makefile                     |   7 +
>  drivers/gpu/drm/sunxi/de2_crtc.c                   | 475 +++++++++++++++++
>  drivers/gpu/drm/sunxi/de2_crtc.h                   |  63 +++
>  drivers/gpu/drm/sunxi/de2_de.c                     | 591 +++++++++++++++++++++
>  drivers/gpu/drm/sunxi/de2_drm.h                    |  47 ++
>  drivers/gpu/drm/sunxi/de2_drv.c                    | 378 +++++++++++++
>  drivers/gpu/drm/sunxi/de2_plane.c                  | 119 +++++
>  11 files changed, 1787 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
>  create mode 100644 drivers/gpu/drm/sunxi/Kconfig
>  create mode 100644 drivers/gpu/drm/sunxi/Makefile
>  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.c
>  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.h
>  create mode 100644 drivers/gpu/drm/sunxi/de2_de.c
>  create mode 100644 drivers/gpu/drm/sunxi/de2_drm.h
>  create mode 100644 drivers/gpu/drm/sunxi/de2_drv.c
>  create mode 100644 drivers/gpu/drm/sunxi/de2_plane.c
> 
> diff --git a/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> new file mode 100644
> index 0000000..f9cd67a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> @@ -0,0 +1,83 @@
> +Allwinner sunxi Display Engine 2 subsystem
> +==========================================
> +
> +The sunxi DE2 subsystem contains a display controller (DE2),

sunxi is a made up name, and doesn't really mean anything. You can
call it either sun8i (because it was introduced in that family).

> +one or two LCD controllers (TCON) and their external interfaces.
> +
> +Display controller
> +==================
> +
> +Required properties:
> +
> +- compatible: value should be one of the following
> +		"allwinner,sun8i-a83t-display-engine"
> +		"allwinner,sun8i-h3-display-engine"
> +
> +- clocks: must include clock specifiers corresponding to entries in the
> +		clock-names property.
> +
> +- clock-names: must contain
> +		"gate": for DE activation
> +		"clock": DE clock

We've been calling them bus and mod.

> +
> +- resets: phandle to the reset of the device
> +
> +- ports: phandle's to the LCD ports

Please use the OF graph.

> +
> +LCD controller
> +==============
> +
> +Required properties:
> +
> +- compatible: value should be one of the following
> +		"allwinner,sun8i-a83t-lcd"
> +
> +- clocks: must include clock specifiers corresponding to entries in the
> +		clock-names property.
> +
> +- clock-names: must contain
> +		"gate": for LCD activation
> +		"clock": pixel clock
> +
> +- resets: phandle to the reset of the device
> +
> +- port: port node with endpoint definitions as defined in
> +	Documentation/devicetree/bindings/media/video-interfaces.txt
> +
> +Example:
> +
> +	de: de-controller@01000000 {
> +		compatible = "allwinner,sun8i-h3-display-engine";
> +		...
> +		clocks = <&&ccu CLK_BUS_DE>, <&ccu CLK_DE>;
> +		clock-names = "gate", "clock";
> +		resets = <&ccu RST_BUS_DE>;
> +		ports = <&lcd0_p>;
> +	};
> +
> +	lcd0: lcd-controller@01c0c000 {
> +		compatible = "allwinner,sun8i-a83t-lcd";
> +		...
> +		clocks = <&ccu CLK_BUS_TCON0>, <&ccu CLK_TCON0>;
> +		clock-names = "gate", "clock";
> +		resets = <&ccu RST_BUS_TCON0>;
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		lcd0_p: port {
> +			lcd0_ep: endpoint {
> +				remote-endpoint = <&hdmi_ep>;
> +			};
> +		};
> +	};
> +
> +	hdmi: hdmi@01ee0000 {
> +		...
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		port {
> +			type = "video";
> +			hdmi_ep: endpoint {
> +				remote-endpoint = <&lcd0_ep>;
> +			};
> +		};
> +	};

> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 483059a..afd576f 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -187,6 +187,8 @@ source "drivers/gpu/drm/shmobile/Kconfig"
>  
>  source "drivers/gpu/drm/sun4i/Kconfig"
>  
> +source "drivers/gpu/drm/sunxi/Kconfig"
> +
>  source "drivers/gpu/drm/omapdrm/Kconfig"
>  
>  source "drivers/gpu/drm/tilcdc/Kconfig"
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 25c7204..120d0bf 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -70,6 +70,7 @@ obj-$(CONFIG_DRM_RCAR_DU) += rcar-du/
>  obj-$(CONFIG_DRM_SHMOBILE) +=shmobile/
>  obj-y			+= omapdrm/
>  obj-$(CONFIG_DRM_SUN4I) += sun4i/
> +obj-$(CONFIG_DRM_SUNXI) += sunxi/
>  obj-y			+= tilcdc/
>  obj-$(CONFIG_DRM_QXL) += qxl/
>  obj-$(CONFIG_DRM_BOCHS) += bochs/
> diff --git a/drivers/gpu/drm/sunxi/Kconfig b/drivers/gpu/drm/sunxi/Kconfig
> new file mode 100644
> index 0000000..56bde2e
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/Kconfig
> @@ -0,0 +1,21 @@
> +#
> +# Allwinner Video configuration
> +#
> +
> +config DRM_SUNXI
> +	tristate "DRM Support for Allwinner Video"
> +	depends on DRM && OF
> +	depends on ARCH_SUNXI || COMPILE_TEST
> +	select DRM_KMS_HELPER
> +	select DRM_KMS_CMA_HELPER
> +	select DRM_GEM_CMA_HELPER
> +	help
> +	  Choose this option if you have a Allwinner chipset.
> +
> +config DRM_SUNXI_DE2
> +	tristate "Support for Allwinner Video with DE2 interface"
> +	depends on DRM_SUNXI
> +	help
> +	  Choose this option if your Allwinner chipset has the DE2 interface
> +	  as the A64, A83T and H3. If M is selected the module will be called
> +	  sunxi-de2-drm.
> diff --git a/drivers/gpu/drm/sunxi/Makefile b/drivers/gpu/drm/sunxi/Makefile
> new file mode 100644
> index 0000000..62220cb
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/Makefile
> @@ -0,0 +1,7 @@
> +#
> +# Makefile for Allwinner's sun8i DRM device driver
> +#
> +
> +sunxi-de2-drm-objs := de2_drv.o de2_de.o de2_crtc.o de2_plane.o
> +
> +obj-$(CONFIG_DRM_SUNXI_DE2) += sunxi-de2-drm.o
> diff --git a/drivers/gpu/drm/sunxi/de2_crtc.c b/drivers/gpu/drm/sunxi/de2_crtc.c
> new file mode 100644
> index 0000000..dae0fab
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/de2_crtc.c
> @@ -0,0 +1,475 @@
> +/*
> + * Allwinner DRM driver - DE2 CRTC
> + *
> + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <linux/component.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <asm/io.h>
> +#include <linux/of_irq.h>
> +
> +#include "de2_drm.h"
> +#include "de2_crtc.h"
> +
> +/* I/O map */
> +
> +struct tcon {
> +	u32 gctl;
> +#define		TCON_GCTL_TCON_En BIT(31)
> +	u32 gint0;
> +#define		TCON_GINT0_TCON1_Vb_Int_En BIT(30)
> +#define		TCON_GINT0_TCON1_Vb_Int_Flag BIT(14)
> +	u32 gint1;
> +	u32 dum0[13];
> +	u32 tcon0_ctl;				/* 0x40 */
> +#define		TCON0_CTL_TCON_En BIT(31)
> +	u32 dum1[19];
> +	u32 tcon1_ctl;				/* 0x90 */
> +#define		TCON1_CTL_TCON_En BIT(31)
> +#define		TCON1_CTL_Interlace_En BIT(20)
> +#define		TCON1_CTL_Start_Delay_SHIFT 4
> +#define		TCON1_CTL_Start_Delay_MASK GENMASK(8, 4)
> +	u32 basic0;			/* XI/YI */
> +	u32 basic1;			/* LS_XO/LS_YO */
> +	u32 basic2;			/* XO/YO */
> +	u32 basic3;			/* HT/HBP */
> +	u32 basic4;			/* VT/VBP */
> +	u32 basic5;			/* HSPW/VSPW */
> +	u32 dum2;
> +	u32 ps_sync;				/* 0xb0 */
> +	u32 dum3[15];
> +	u32 io_pol;				/* 0xf0 */
> +#define		TCON1_IO_POL_IO0_inv BIT(24)
> +#define		TCON1_IO_POL_IO1_inv BIT(25)
> +#define		TCON1_IO_POL_IO2_inv BIT(26)
> +	u32 io_tri;
> +	u32 dum4[2];
> +
> +	u32 ceu_ctl;				/* 0x100 */
> +#define     TCON_CEU_CTL_ceu_en BIT(31)
> +	u32 dum5[3];
> +	u32 ceu_rr;
> +	u32 ceu_rg;
> +	u32 ceu_rb;
> +	u32 ceu_rc;
> +	u32 ceu_gr;
> +	u32 ceu_gg;
> +	u32 ceu_gb;
> +	u32 ceu_gc;
> +	u32 ceu_br;
> +	u32 ceu_bg;
> +	u32 ceu_bb;
> +	u32 ceu_bc;
> +	u32 ceu_rv;
> +	u32 ceu_gv;
> +	u32 ceu_bv;
> +	u32 dum6[45];
> +
> +	u32 mux_ctl;				/* 0x200 */
> +	u32 dum7[63];
> +
> +	u32 fill_ctl;				/* 0x300 */
> +	u32 fill_start0;
> +	u32 fill_end0;
> +	u32 fill_data0;
> +};

Please use defines instead of the structures.

> +
> +#define XY(x, y) (((x) << 16) | (y))
> +
> +#define tcon_read(base, member) \
> +	readl_relaxed(base + offsetof(struct tcon, member))
> +#define tcon_write(base, member, data) \
> +	writel_relaxed(data, base + offsetof(struct tcon, member))
> +
> +/* vertical blank functions */
> +static void de2_atomic_flush(struct drm_crtc *crtc,
> +			struct drm_crtc_state *old_state)
> +{
> +	struct drm_pending_vblank_event *event = crtc->state->event;
> +
> +	if (event) {
> +		crtc->state->event = NULL;
> +		spin_lock_irq(&crtc->dev->event_lock);
> +		if (drm_crtc_vblank_get(crtc) == 0)
> +			drm_crtc_arm_vblank_event(crtc, event);
> +		else
> +			drm_crtc_send_vblank_event(crtc, event);
> +		spin_unlock_irq(&crtc->dev->event_lock);
> +	}
> +}
> +
> +static irqreturn_t de2_lcd_irq(int irq, void *dev_id)
> +{
> +	struct lcd *lcd = (struct lcd *) dev_id;
> +	u32 isr;
> +
> +	isr = tcon_read(lcd->mmio, gint0);
> +
> +	drm_crtc_handle_vblank(&lcd->crtc);
> +
> +	tcon_write(lcd->mmio, gint0, isr & ~TCON_GINT0_TCON1_Vb_Int_Flag);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +int de2_enable_vblank(struct drm_device *drm, unsigned crtc)
> +{
> +	struct priv *priv = drm->dev_private;
> +	struct lcd *lcd = priv->lcds[crtc];
> +
> +	tcon_write(lcd->mmio, gint0,
> +			tcon_read(lcd->mmio, gint0) |
> +					TCON_GINT0_TCON1_Vb_Int_En);

That's a weird indentation

> +	return 0;
> +}
> +
> +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> +{
> +	struct priv *priv = drm->dev_private;
> +	struct lcd *lcd = priv->lcds[crtc];
> +
> +	tcon_write(lcd->mmio, gint0,
> +			 tcon_read(lcd->mmio, gint0) &
> +					~TCON_GINT0_TCON1_Vb_Int_En);
> +}
> +
> +/* panel functions */

Panel functions? In the CRTC driver?

> +static void de2_set_frame_timings(struct lcd *lcd)
> +{
> +	struct drm_crtc *crtc = &lcd->crtc;
> +	const struct drm_display_mode *mode = &crtc->mode;
> +	int interlace = mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 1;
> +	int start_delay;
> +	u32 data;
> +
> +	data = XY(mode->hdisplay - 1, mode->vdisplay / interlace - 1);
> +	tcon_write(lcd->mmio, basic0, data);
> +	tcon_write(lcd->mmio, basic1, data);
> +	tcon_write(lcd->mmio, basic2, data);
> +	tcon_write(lcd->mmio, basic3,
> +			XY(mode->htotal - 1,
> +				mode->htotal - mode->hsync_start - 1));
> +	tcon_write(lcd->mmio, basic4,
> +			XY(mode->vtotal * (3 - interlace),
> +				mode->vtotal - mode->vsync_start - 1));
> +	tcon_write(lcd->mmio, basic5,
> +			 XY(mode->hsync_end - mode->hsync_start - 1,
> +				mode->vsync_end - mode->vsync_start - 1));
> +
> +	tcon_write(lcd->mmio, ps_sync, XY(1, 1));
> +
> +	data = TCON1_IO_POL_IO2_inv;
> +	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
> +		data |= TCON1_IO_POL_IO0_inv;
> +	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
> +		data |= TCON1_IO_POL_IO1_inv;
> +	tcon_write(lcd->mmio, io_pol, data);
> +
> +	tcon_write(lcd->mmio, ceu_ctl,
> +		tcon_read(lcd->mmio, ceu_ctl) & ~TCON_CEU_CTL_ceu_en);
> +
> +	data = tcon_read(lcd->mmio, tcon1_ctl);
> +	if (interlace == 2)
> +		data |= TCON1_CTL_Interlace_En;
> +	else
> +		data &= ~TCON1_CTL_Interlace_En;
> +	tcon_write(lcd->mmio, tcon1_ctl, data);
> +
> +	tcon_write(lcd->mmio, fill_ctl, 0);
> +	tcon_write(lcd->mmio, fill_start0, mode->vtotal + 1);
> +	tcon_write(lcd->mmio, fill_end0, mode->vtotal);
> +	tcon_write(lcd->mmio, fill_data0, 0);
> +
> +	start_delay = (mode->vtotal - mode->vdisplay) / interlace - 5;
> +	if (start_delay > 31)
> +		start_delay = 31;
> +	data = tcon_read(lcd->mmio, tcon1_ctl);
> +	data &= ~TCON1_CTL_Start_Delay_MASK;
> +	data |= start_delay << TCON1_CTL_Start_Delay_SHIFT;
> +	tcon_write(lcd->mmio, tcon1_ctl, data);
> +
> +	tcon_write(lcd->mmio, io_tri, 0x0fffffff);
> +}

Some comments here would be nice, there's a lot of non trivial things.

> +
> +static void de2_crtc_enable(struct drm_crtc *crtc)
> +{
> +	struct lcd *lcd = crtc_to_lcd(crtc);
> +	struct drm_display_mode *mode = &crtc->mode;
> +
> +	DRM_DEBUG_DRIVER("\n");

Log something useful, or don't.

> +
> +	clk_set_rate(lcd->clk, mode->clock * 1000);
> +
> +	de2_set_frame_timings(lcd);
> +
> +	tcon_write(lcd->mmio, tcon1_ctl,
> +		tcon_read(lcd->mmio, tcon1_ctl) | TCON1_CTL_TCON_En);
> +
> +	de2_de_panel_init(lcd->priv, lcd->num, mode);

panel_init in the CRTC enable? Shouldn't that be in the panel driver?
or at least the encoder?

> +
> +	drm_mode_debug_printmodeline(mode);

This is already printed by the core.

> +}
> +
> +static void de2_crtc_disable(struct drm_crtc *crtc)
> +{
> +	struct lcd *lcd = crtc_to_lcd(crtc);
> +	unsigned long flags;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	tcon_write(lcd->mmio, tcon1_ctl,
> +		tcon_read(lcd->mmio, tcon1_ctl) & ~TCON1_CTL_TCON_En);
> +
> +	if (crtc->state->event && !crtc->state->active) {
> +		spin_lock_irqsave(&crtc->dev->event_lock, flags);
> +		drm_crtc_send_vblank_event(crtc, crtc->state->event);
> +		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +		crtc->state->event = NULL;
> +	}
> +}
> +
> +static const struct drm_crtc_funcs de2_crtc_funcs = {
> +	.destroy	= drm_crtc_cleanup,
> +	.set_config	= drm_atomic_helper_set_config,
> +	.page_flip	= drm_atomic_helper_page_flip,
> +	.reset		= drm_atomic_helper_crtc_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> +};
> +
> +static const struct drm_crtc_helper_funcs de2_crtc_helper_funcs = {
> +	.atomic_flush	= de2_atomic_flush,
> +	.enable		= de2_crtc_enable,
> +	.disable	= de2_crtc_disable,
> +};
> +
> +static void de2_tcon_init(struct lcd *lcd)
> +{
> +	tcon_write(lcd->mmio, tcon0_ctl,
> +		tcon_read(lcd->mmio, tcon0_ctl) & ~TCON0_CTL_TCON_En);
> +	tcon_write(lcd->mmio, tcon1_ctl,
> +		tcon_read(lcd->mmio, tcon1_ctl) & ~TCON1_CTL_TCON_En);
> +	tcon_write(lcd->mmio, gctl,
> +		tcon_read(lcd->mmio, gctl) & ~TCON_GCTL_TCON_En);
> +
> +	/* disable/ack interrupts */
> +	tcon_write(lcd->mmio, gint0, 0);
> +}
> +
> +static void de2_tcon_enable(struct lcd *lcd)
> +{
> +	tcon_write(lcd->mmio, gctl,
> +		tcon_read(lcd->mmio, gctl) | TCON_GCTL_TCON_En);
> +}
> +
> +static int de2_crtc_init(struct drm_device *drm, struct lcd *lcd)
> +{
> +	struct drm_crtc *crtc = &lcd->crtc;
> +	int ret;
> +
> +	ret = de2_plane_init(drm, lcd);
> +	if (ret < 0)
> +		return ret;
> +
> +	drm_crtc_helper_add(crtc, &de2_crtc_helper_funcs);
> +
> +	ret = drm_crtc_init_with_planes(drm, crtc,
> +					&lcd->planes[DE2_PRIMARY_PLANE],
> +					&lcd->planes[DE2_CURSOR_PLANE],
> +					&de2_crtc_funcs, NULL);
> +	if (ret < 0)
> +		return ret;
> +
> +	de2_tcon_enable(lcd);
> +
> +	de2_de_enable(lcd->priv, lcd->num);
> +
> +	return 0;
> +}
> +
> +/*
> + * device init
> + */
> +static int de2_lcd_bind(struct device *dev, struct device *master,
> +			void *data)
> +{
> +	struct drm_device *drm = data;
> +	struct priv *priv = drm->dev_private;
> +	struct lcd *lcd = dev_get_drvdata(dev);
> +	int ret;
> +
> +	lcd->priv = priv;
> +
> +	/* (only 2 LCDs) */
> +	lcd->crtc_idx = priv->lcds[0] ? 1 : 0;
> +	priv->lcds[lcd->crtc_idx] = lcd;
> +
> +	ret = de2_crtc_init(drm, lcd);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to init the crtc\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void de2_lcd_unbind(struct device *dev, struct device *master,
> +			void *data)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct lcd *lcd = platform_get_drvdata(pdev);
> +
> +	if (lcd->mmio) {
> +		if (lcd->priv)
> +			de2_de_disable(lcd->priv, lcd->num);
> +		tcon_write(lcd->mmio, gctl,
> +			tcon_read(lcd->mmio, gctl) & ~TCON_GCTL_TCON_En);
> +	}
> +}
> +
> +static const struct component_ops de2_lcd_ops = {
> +	.bind = de2_lcd_bind,
> +	.unbind = de2_lcd_unbind,
> +};
> +
> +static int de2_lcd_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node, *tmp, *parent, *port;
> +	struct lcd *lcd;
> +	struct resource *res;
> +	int id, irq, ret;
> +
> +	id = of_alias_get_id(np, "lcd");
> +	if (id < 0) {
> +		dev_err(dev, "no alias for lcd\n");
> +		id = 0;
> +	}
> +	lcd = devm_kzalloc(dev, sizeof *lcd, GFP_KERNEL);
> +	if (!lcd) {
> +		dev_err(dev, "failed to allocate private data\n");
> +		return -ENOMEM;
> +	}
> +	dev_set_drvdata(dev, lcd);
> +	lcd->dev = dev;
> +	lcd->num = id;

What do you need this number for?

> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		dev_err(dev, "failed to get memory resource\n");
> +		return -EINVAL;
> +	}
> +
> +	lcd->mmio = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(lcd->mmio)) {
> +		dev_err(dev, "failed to map registers\n");
> +		return PTR_ERR(lcd->mmio);
> +	}
> +
> +	snprintf(lcd->name, sizeof(lcd->name), "sunxi-lcd%d", id);
> +
> +	/* possible CRTCs */
> +	parent = np;
> +	tmp = of_get_child_by_name(np, "ports");
> +	if (tmp)
> +		parent = tmp;
> +	port = of_get_child_by_name(parent, "port");
> +	of_node_put(tmp);
> +	if (!port) {
> +		dev_err(dev, "no port node\n");
> +		return -ENXIO;
> +	}
> +	lcd->crtc.port = port;
> +
> +	lcd->gate = devm_clk_get(dev, "gate");		/* optional */

Having some kind of error checking would still be nice.

> +
> +	lcd->clk = devm_clk_get(dev, "clock");
> +	if (IS_ERR(lcd->clk)) {
> +		dev_err(dev, "video clock err %d\n", (int) PTR_ERR(lcd->clk));
> +		ret = PTR_ERR(lcd->clk);
> +		goto err;
> +	}
> +
> +	lcd->rstc = devm_reset_control_get_optional(dev, NULL);

Ditto.

> +
> +	irq = irq_of_parse_and_map(np, 0);
> +	if (irq <= 0 || irq == NO_IRQ) {
> +		dev_err(dev, "unable to get irq lcd %d\n", id);
> +		ret = -EINVAL;
> +		goto err;
> +	}

You can use platform_get_irq for that.

> +
> +	if (!IS_ERR(lcd->rstc)) {
> +		ret = reset_control_deassert(lcd->rstc);
> +		if (ret) {
> +			dev_err(dev, "reset deassert err %d\n", ret);
> +			goto err;
> +		}
> +	}
> +
> +	if (!IS_ERR(lcd->gate)) {
> +		ret = clk_prepare_enable(lcd->gate);
> +		if (ret)
> +			goto err2;
> +	}
> +
> +	ret = clk_prepare_enable(lcd->clk);
> +	if (ret)
> +		goto err2;

Is there any reason not to do that in the enable / disable? Leaving
clocks running while the device has no guarantee that it's going to be
used seems like a waste of resources.

> +
> +	de2_tcon_init(lcd);
> +
> +	ret = devm_request_irq(dev, irq, de2_lcd_irq, 0,
> +				lcd->name, lcd);
> +	if (ret < 0) {
> +		dev_err(dev, "unable to request irq %d\n", irq);
> +		goto err2;
> +	}
> +
> +	return component_add(dev, &de2_lcd_ops);
> +
> +err2:
> +	if (!IS_ERR_OR_NULL(lcd->rstc))
> +		reset_control_assert(lcd->rstc);
> +	clk_disable_unprepare(lcd->gate);
> +	clk_disable_unprepare(lcd->clk);
> +err:
> +	of_node_put(lcd->crtc.port);
> +	return ret;
> +}
> +
> +static int de2_lcd_remove(struct platform_device *pdev)
> +{
> +	struct lcd *lcd = platform_get_drvdata(pdev);
> +
> +	component_del(&pdev->dev, &de2_lcd_ops);
> +
> +	if (!IS_ERR_OR_NULL(lcd->rstc))
> +		reset_control_assert(lcd->rstc);
> +	clk_disable_unprepare(lcd->gate);
> +	clk_disable_unprepare(lcd->clk);
> +	of_node_put(lcd->crtc.port);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id de2_lcd_ids[] = {
> +	{ .compatible = "allwinner,sun8i-a83t-lcd", },
> +	{ }
> +};
> +
> +struct platform_driver de2_lcd_platform_driver = {
> +	.probe = de2_lcd_probe,
> +	.remove = de2_lcd_remove,
> +	.driver = {
> +		.name = "sunxi-de2-lcd",
> +		.of_match_table = of_match_ptr(de2_lcd_ids),
> +	},
> +};
> diff --git a/drivers/gpu/drm/sunxi/de2_crtc.h b/drivers/gpu/drm/sunxi/de2_crtc.h
> new file mode 100644
> index 0000000..efbe45d
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/de2_crtc.h
> @@ -0,0 +1,63 @@
> +#ifndef __DE2_CRTC_H__
> +#define __DE2_CRTC_H__
> +/*
> + * Copyright (C) 2016 Jean-François Moine
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +#include <drm/drm_plane_helper.h>
> +
> +struct priv;
> +
> +enum de2_plane2 {
> +	DE2_PRIMARY_PLANE,
> +	DE2_CURSOR_PLANE,
> +	DE2_VI_PLANE,
> +	DE2_N_PLANES,
> +};
> +struct lcd {
> +	void __iomem *mmio;
> +
> +	struct device *dev;
> +	struct drm_crtc crtc;
> +	struct priv *priv;	/* DRM/DE private data */
> +
> +	short num;		/* LCD number in hardware */
> +	short crtc_idx;		/* CRTC index in drm */
> +
> +	struct clk *clk;
> +	struct clk *gate;
> +	struct reset_control *rstc;
> +
> +	char name[16];
> +
> +	struct drm_pending_vblank_event *event;
> +
> +	struct drm_plane planes[DE2_N_PLANES];
> +};
> +
> +#define crtc_to_lcd(x) container_of(x, struct lcd, crtc)
> +
> +/* in de2_de.c */
> +void de2_de_enable(struct priv *priv, int lcd_num);
> +void de2_de_disable(struct priv *priv, int lcd_num);
> +void de2_de_hw_init(struct priv *priv, int lcd_num);
> +void de2_de_panel_init(struct priv *priv, int lcd_num,
> +			struct drm_display_mode *mode);
> +void de2_de_plane_disable(struct priv *priv,
> +			int lcd_num, int plane_ix);
> +void de2_de_plane_update(struct priv *priv,
> +			int lcd_num, int plane_ix,
> +			struct drm_plane_state *state,
> +			struct drm_plane_state *old_state);

Does it need to be exported?

> +
> +/* in de2_plane.c */
> +int de2_plane_init(struct drm_device *drm, struct lcd *lcd);
> +
> +#endif /* __DE2_CRTC_H__ */
> diff --git a/drivers/gpu/drm/sunxi/de2_de.c b/drivers/gpu/drm/sunxi/de2_de.c
> new file mode 100644
> index 0000000..0d8cb62
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/de2_de.c
> @@ -0,0 +1,591 @@
> +/*
> + * ALLWINNER DRM driver - Display Engine 2
> + *
> + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> + * Copyright (c) 2016 Allwinnertech Co., Ltd.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <asm/io.h>
> +#include <drm/drm_gem_cma_helper.h>
> +
> +#include "de2_drm.h"
> +#include "de2_crtc.h"
> +
> +static DEFINE_SPINLOCK(de_lock);
> +
> +#define DE_CLK_RATE_A83T 504000000	/* pll-de */
> +#define DE_CLK_RATE_H3 432000000	/* de */

This can be set in the DT.

> +
> +/* I/O map */
> +
> +#define DE_MOD_REG 0x0000	/* 1 bit per LCD */
> +#define DE_GATE_REG 0x0004
> +#define DE_RESET_REG 0x0008
> +#define DE_DIV_REG 0x000c	/* 4 bits per LCD */
> +#define DE_SEL_REG 0x0010
> +
> +#define DE_MUX0_BASE 0x00100000
> +#define DE_MUX1_BASE 0x00200000
> +
> +/* MUX registers (addr / MUX base) */
> +#define DE_MUX_GLB_REGS 0x00000		/* global control */
> +#define DE_MUX_BLD_REGS 0x01000		/* alpha blending */
> +#define DE_MUX_CHAN_REGS 0x02000	/* VI/UI overlay channels */
> +#define		DE_MUX_CHAN_SZ 0x1000	/* size of a channel */
> +#define DE_MUX_VSU_REGS 0x20000		/* VSU */
> +#define DE_MUX_GSU1_REGS 0x30000	/* GSUs */
> +#define DE_MUX_GSU2_REGS 0x40000
> +#define DE_MUX_GSU3_REGS 0x50000
> +#define DE_MUX_FCE_REGS 0xa0000		/* FCE */
> +#define DE_MUX_BWS_REGS 0xa2000		/* BWS */
> +#define DE_MUX_LTI_REGS 0xa4000		/* LTI */
> +#define DE_MUX_PEAK_REGS 0xa6000	/* PEAK */
> +#define DE_MUX_ASE_REGS 0xa8000		/* ASE */
> +#define DE_MUX_FCC_REGS 0xaa000		/* FCC */
> +#define DE_MUX_DCSC_REGS 0xb0000	/* DCSC/SMBL */
> +
> +/* global control */
> +struct de_glb {
> +	u32 ctl;
> +#define		DE_MUX_GLB_CTL_rt_en BIT(0)
> +#define		DE_MUX_GLB_CTL_finish_irq_en BIT(4)
> +#define		DE_MUX_GLB_CTL_rtwb_port BIT(12)
> +	u32 status;
> +	u32 dbuff;
> +	u32 size;
> +};
> +
> +/* alpha blending */
> +struct de_bld {
> +	u32 fcolor_ctl;			/* 00 */
> +	struct {
> +		u32 fcolor;
> +		u32 insize;
> +		u32 offset;
> +		u32 dum;
> +	} attr[4];
> +	u32 dum0[15];			/* (end of clear offset) */
> +	u32 route;			/* 80 */
> +	u32 premultiply;
> +	u32 bkcolor;
> +	u32 output_size;
> +	u32 bld_mode[4];
> +	u32 dum1[4];
> +	u32 ck_ctl;			/* b0 */
> +	u32 ck_cfg;
> +	u32 dum2[2];
> +	u32 ck_max[4];			/* c0 */
> +	u32 dum3[4];
> +	u32 ck_min[4];			/* e0 */
> +	u32 dum4[3];
> +	u32 out_ctl;			/* fc */
> +};
> +
> +/* VI channel */
> +struct de_vi {
> +	struct {
> +		u32 attr;
> +#define			VI_CFG_ATTR_en BIT(0)
> +#define			VI_CFG_ATTR_fcolor_en BIT(4)
> +#define			VI_CFG_ATTR_fmt_SHIFT 8
> +#define			VI_CFG_ATTR_fmt_MASK GENMASK(12, 8)
> +#define			VI_CFG_ATTR_ui_sel BIT(15)
> +#define			VI_CFG_ATTR_top_down BIT(23)
> +		u32 size;
> +		u32 coord;
> +#define VI_N_PLANES 3
> +		u32 pitch[VI_N_PLANES];
> +		u32 top_laddr[VI_N_PLANES];
> +		u32 bot_laddr[VI_N_PLANES];
> +	} cfg[4];
> +	u32 fcolor[4];			/* c0 */
> +	u32 top_haddr[VI_N_PLANES];	/* d0 */
> +	u32 bot_haddr[VI_N_PLANES];	/* dc */
> +	u32 ovl_size[2];		/* e8 */
> +	u32 hori[2];			/* f0 */
> +	u32 vert[2];			/* f8 */
> +};
> +
> +/* UI channel */
> +struct de_ui {
> +	struct {
> +		u32 attr;
> +#define			UI_CFG_ATTR_en BIT(0)
> +#define			UI_CFG_ATTR_alpmod_SHIFT 1
> +#define			UI_CFG_ATTR_alpmod_MASK GENMASK(2, 1)
> +#define			UI_CFG_ATTR_fcolor_en BIT(4)
> +#define			UI_CFG_ATTR_fmt_SHIFT 8
> +#define			UI_CFG_ATTR_fmt_MASK GENMASK(12, 8)
> +#define			UI_CFG_ATTR_top_down BIT(23)
> +#define			UI_CFG_ATTR_alpha_SHIFT 24
> +#define			UI_CFG_ATTR_alpha_MASK GENMASK(31, 24)
> +		u32 size;
> +		u32 coord;
> +		u32 pitch;
> +		u32 top_laddr;
> +		u32 bot_laddr;
> +		u32 fcolor;
> +		u32 dum;
> +	} cfg[4];			/* 00 */
> +	u32 top_haddr;			/* 80 */
> +	u32 bot_haddr;
> +	u32 ovl_size;			/* 88 */
> +};

Please use defines instead of the structures.

> +
> +/* coordinates and sizes */
> +#define XY(x, y) (((y) << 16) | (x))
> +#define WH(w, h) (((h - 1) << 16) | (w - 1))
> +
> +/* UI video formats */
> +#define DE2_FORMAT_ARGB_8888 0
> +#define DE2_FORMAT_BGRA_8888 3
> +#define DE2_FORMAT_XRGB_8888 4
> +#define DE2_FORMAT_RGB_888 8
> +#define DE2_FORMAT_BGR_888 9
> +
> +/* VI video formats */
> +#define DE2_FORMAT_YUV422_I_YVYU 1	/* Y-V-Y-U */
> +#define DE2_FORMAT_YUV422_I_UYVY 2	/* U-Y-V-Y */
> +#define DE2_FORMAT_YUV422_I_YUYV 3	/* Y-U-Y-V */
> +#define DE2_FORMAT_YUV422_P 6		/* YYYY UU VV planar */
> +#define DE2_FORMAT_YUV420_P 10		/* YYYY U V planar */
> +
> +#define glb_read(base, member) \
> +	readl_relaxed(base + offsetof(struct de_glb, member))
> +#define glb_write(base, member, data) \
> +	writel_relaxed(data, base + offsetof(struct de_glb, member))
> +#define bld_read(base, member) \
> +	readl_relaxed(base + offsetof(struct de_bld, member))
> +#define bld_write(base, member, data) \
> +	writel_relaxed(data, base + offsetof(struct de_bld, member))
> +#define ui_read(base, member) \
> +	readl_relaxed(base + offsetof(struct de_ui, member))
> +#define ui_write(base, member, data) \
> +	writel_relaxed(data, base + offsetof(struct de_ui, member))
> +#define vi_read(base, member) \
> +	readl_relaxed(base + offsetof(struct de_vi, member))
> +#define vi_write(base, member, data) \
> +	writel_relaxed(data, base + offsetof(struct de_vi, member))
> +
> +static const struct {
> +	char chan;
> +	char layer;
> +	char pipe;
> +} plane2layer[DE2_N_PLANES] = {
> +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> +	[DE2_VI_PLANE] =	{0, 1, 0},
> +};

Comments?

> +static inline void de_write(struct priv *priv, int reg, u32 data)
> +{
> +	writel_relaxed(data, priv->mmio + reg);
> +}
> +
> +static inline u32 de_read(struct priv *priv, int reg)
> +{
> +	return readl_relaxed(priv->mmio + reg);
> +}
> +
> +static void de_lcd_select(struct priv *priv,
> +			int lcd_num,
> +			void __iomem *mux_o)
> +{
> +	u32 data;
> +
> +	/* select the LCD */
> +	data = de_read(priv, DE_SEL_REG);
> +	data &= ~1;
> +	de_write(priv, DE_SEL_REG, data);
> +
> +	/* double register switch */
> +	glb_write(mux_o + DE_MUX_GLB_REGS, dbuff, 1);
> +}
> +
> +void de2_de_plane_update(struct priv *priv,
> +			int lcd_num, int plane_ix,
> +			struct drm_plane_state *state,
> +			struct drm_plane_state *old_state)
> +{
> +	struct drm_framebuffer *fb = state->fb;
> +	struct drm_gem_cma_object *gem;
> +	void __iomem *mux_o = priv->mmio;
> +	void __iomem *chan_o;
> +	u32 size = WH(state->crtc_w, state->crtc_h);
> +	u32 coord;
> +	u32 screen_size;
> +	u32 data, fcolor;
> +	u32 ui_sel, alpha_glob;
> +	int chan, layer, x, y;
> +	unsigned fmt;
> +	unsigned long flags;
> +
> +	chan = plane2layer[plane_ix].chan;
> +	layer = plane2layer[plane_ix].layer;
> +
> +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> +	chan_o = mux_o;
> +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> +
> +	x = state->crtc_x >= 0 ? state->crtc_x : 0;
> +	y = state->crtc_y >= 0 ? state->crtc_y : 0;
> +	coord = XY(x, y);
> +
> +	/* handle the cursor move */
> +	if (plane_ix == DE2_CURSOR_PLANE
> +	 && fb == old_state->fb) {
> +		spin_lock_irqsave(&de_lock, flags);
> +		de_lcd_select(priv, lcd_num, mux_o);
> +		if (chan == 0)
> +			vi_write(chan_o, cfg[layer].coord, coord);
> +		else
> +			ui_write(chan_o, cfg[layer].coord, coord);
> +		spin_unlock_irqrestore(&de_lock, flags);
> +		return;
> +	}
> +
> +	gem = drm_fb_cma_get_gem_obj(fb, 0);
> +
> +	ui_sel = alpha_glob = 0;
> +	switch (fb->pixel_format) {
> +	case DRM_FORMAT_ARGB8888:
> +		fmt = DE2_FORMAT_ARGB_8888;
> +		ui_sel = VI_CFG_ATTR_ui_sel;
> +		break;
> +	case DRM_FORMAT_BGRA8888:
> +		fmt = DE2_FORMAT_BGRA_8888;
> +		ui_sel = VI_CFG_ATTR_ui_sel;
> +		break;
> +	case DRM_FORMAT_XRGB8888:
> +		fmt = DE2_FORMAT_XRGB_8888;
> +		ui_sel = VI_CFG_ATTR_ui_sel;
> +		alpha_glob = (1 << UI_CFG_ATTR_alpmod_SHIFT) |
> +				(0xff << UI_CFG_ATTR_alpha_SHIFT);
> +		break;
> +	case DRM_FORMAT_RGB888:
> +		fmt = DE2_FORMAT_RGB_888;
> +		ui_sel = VI_CFG_ATTR_ui_sel;
> +		break;
> +	case DRM_FORMAT_BGR888:
> +		fmt = DE2_FORMAT_BGR_888;
> +		ui_sel = VI_CFG_ATTR_ui_sel;
> +		break;
> +	case DRM_FORMAT_YUYV:
> +		fmt = DE2_FORMAT_YUV422_I_YUYV;
> +		break;
> +	case DRM_FORMAT_YVYU:
> +		fmt = DE2_FORMAT_YUV422_I_YVYU;
> +		break;
> +	case DRM_FORMAT_YUV422:
> +		fmt = DE2_FORMAT_YUV422_P;
> +		break;
> +	case DRM_FORMAT_YUV420:
> +		fmt = DE2_FORMAT_YUV420_P;
> +		break;
> +	case DRM_FORMAT_UYVY:
> +		fmt = DE2_FORMAT_YUV422_I_UYVY;
> +		break;
> +	default:
> +		pr_err("format %.4s not yet treated\n",
> +			(char *) &fb->pixel_format);
> +		return;
> +	}
> +
> +	spin_lock_irqsave(&de_lock, flags);
> +
> +	screen_size = plane_ix == DE2_PRIMARY_PLANE ?
> +			size :
> +			glb_read(mux_o + DE_MUX_GLB_REGS, size);
> +
> +	/* prepare the activation of alpha blending (1 bit per plane) */
> +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl)
> +			| (0x100 << plane2layer[plane_ix].pipe);
> +
> +	de_lcd_select(priv, lcd_num, mux_o);
> +
> +	if (chan == 0) {	/* VI channel */
> +		int i;
> +
> +		data = VI_CFG_ATTR_en | (fmt << VI_CFG_ATTR_fmt_SHIFT) |
> +					ui_sel;
> +		vi_write(chan_o, cfg[layer].attr, data);
> +		vi_write(chan_o, cfg[layer].size, size);
> +		vi_write(chan_o, cfg[layer].coord, coord);
> +		for (i = 0; i < VI_N_PLANES; i++) {
> +			vi_write(chan_o, cfg[layer].pitch[i],
> +					fb->pitches[i] ? fb->pitches[i] :
> +							fb->pitches[0]);
> +			vi_write(chan_o, cfg[layer].top_laddr[i],
> +				gem->paddr + fb->offsets[i]);
> +			vi_write(chan_o, fcolor[layer], 0xff000000);
> +		}
> +		if (layer == 0)
> +			vi_write(chan_o, ovl_size[0], screen_size);
> +
> +	} else {		/* UI channel */
> +		data = UI_CFG_ATTR_en | (fmt << UI_CFG_ATTR_fmt_SHIFT) |
> +			alpha_glob;
> +		ui_write(chan_o, cfg[layer].attr, data);
> +		ui_write(chan_o, cfg[layer].size, size);
> +		ui_write(chan_o, cfg[layer].coord, coord);
> +		ui_write(chan_o, cfg[layer].pitch, fb->pitches[0]);
> +		ui_write(chan_o, cfg[layer].top_laddr,
> +				gem->paddr + fb->offsets[0]);
> +		if (layer == 0)
> +			ui_write(chan_o, ovl_size, screen_size);
> +	}
> +	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, fcolor);
> +
> +	spin_unlock_irqrestore(&de_lock, flags);
> +}

Splitting that into functions would make it a bit more trivial and
readable.

> +void de2_de_plane_disable(struct priv *priv,
> +			int lcd_num, int plane_ix)
> +{
> +	void __iomem *mux_o = priv->mmio;
> +	void __iomem *chan_o;
> +	u32 fcolor;
> +	int chan, layer, chan_disable = 0;
> +	unsigned long flags;
> +
> +	chan = plane2layer[plane_ix].chan;
> +	layer = plane2layer[plane_ix].layer;
> +
> +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> +	chan_o = mux_o;
> +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> +
> +	/* (only 2 layers) */
> +	if (chan == 0) {
> +		if (vi_read(chan_o, cfg[1 - layer].attr) == 0)
> +			chan_disable = 1;
> +	} else {
> +		if (ui_read(chan_o, cfg[1 - layer].attr) == 0)
> +			chan_disable = 1;
> +	}
> +
> +	spin_lock_irqsave(&de_lock, flags);
> +
> +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl);
> +
> +	de_lcd_select(priv, lcd_num, mux_o);
> +
> +	if (chan == 0)
> +		vi_write(chan_o, cfg[layer].attr, 0);
> +	else
> +		ui_write(chan_o, cfg[layer].attr, 0);
> +
> +	if (chan_disable)
> +		bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl,
> +			fcolor & ~(0x100 << plane2layer[plane_ix].pipe));
> +
> +	spin_unlock_irqrestore(&de_lock, flags);
> +}

Can't you just disable it?

> +void de2_de_panel_init(struct priv *priv, int lcd_num,
> +			struct drm_display_mode *mode)
> +{
> +	void __iomem *mux_o = priv->mmio;
> +	u32 size = WH(mode->hdisplay, mode->vdisplay);
> +	unsigned i;
> +	unsigned long flags;
> +
> +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> +
> +	DRM_DEBUG_DRIVER("%dx%d\n", mode->hdisplay, mode->vdisplay);
> +
> +	spin_lock_irqsave(&de_lock, flags);
> +
> +	de_lcd_select(priv, lcd_num, mux_o);
> +
> +	glb_write(mux_o + DE_MUX_GLB_REGS, size, size);
> +
> +	/* set alpha blending */
> +	for (i = 0; i < 4; i++) {
> +		bld_write(mux_o + DE_MUX_BLD_REGS, attr[i].fcolor, 0xff000000);
> +		bld_write(mux_o + DE_MUX_BLD_REGS, attr[i].insize, size);
> +	}
> +	bld_write(mux_o + DE_MUX_BLD_REGS, output_size, size);
> +	bld_write(mux_o + DE_MUX_BLD_REGS, out_ctl,
> +			mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 0);
> +
> +	spin_unlock_irqrestore(&de_lock, flags);
> +}
> +
> +void de2_de_enable(struct priv *priv, int lcd_num)
> +{
> +	void __iomem *mux_o = priv->mmio;
> +	unsigned chan, i;
> +	u32 size = WH(1920, 1080);
> +	u32 data;
> +	unsigned long flags;
> +
> +	DRM_DEBUG_DRIVER("lcd %d\n", lcd_num);
> +
> +	de_write(priv, DE_RESET_REG,
> +			de_read(priv, DE_RESET_REG) |
> +				(lcd_num == 0 ? 1 : 4));
> +	data = 1 << lcd_num;			/* 1 bit / lcd */
> +	de_write(priv, DE_GATE_REG,
> +			de_read(priv, DE_GATE_REG) | data);
> +	de_write(priv, DE_MOD_REG,
> +			de_read(priv, DE_MOD_REG) | data);
> +
> +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> +
> +	spin_lock_irqsave(&de_lock, flags);
> +
> +	/* select the LCD */
> +	data = de_read(priv, DE_SEL_REG);
> +	if (lcd_num == 0)
> +		data &= ~1;
> +	else
> +		data |= 1;
> +	de_write(priv, DE_SEL_REG, data);
> +
> +	/* start init */
> +	glb_write(mux_o + DE_MUX_GLB_REGS, ctl,
> +		DE_MUX_GLB_CTL_rt_en | DE_MUX_GLB_CTL_rtwb_port);
> +	glb_write(mux_o + DE_MUX_GLB_REGS, status, 0);
> +	glb_write(mux_o + DE_MUX_GLB_REGS, dbuff, 1);	/* dble reg switch */
> +	glb_write(mux_o + DE_MUX_GLB_REGS, size, size);
> +
> +	/* clear the VI/UI channels */
> +	for (chan = 0; chan < 4; chan++) {
> +		void __iomem *chan_o = mux_o + DE_MUX_CHAN_REGS +
> +				DE_MUX_CHAN_SZ * chan;
> +
> +		memset_io(chan_o, 0, chan == 0 ?
> +				sizeof(struct de_vi) : sizeof(struct de_ui));
> +
> +		/* only 1 VI and 1 UI in lcd1 */
> +		if (chan == 2 && lcd_num == 1)
> +			break;
> +	}
> +
> +	/* clear and set alpha blending */
> +	memset_io(mux_o + DE_MUX_BLD_REGS, 0, offsetof(struct de_bld, dum0));
> +	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, 0x00000101);
> +						/* fcolor for primary */
> +
> +	/* prepare route for planes */
> +	data = 0;
> +	for (i = 0; i < DE2_N_PLANES; i++)
> +		data |= plane2layer[i].chan << (plane2layer[i].pipe * 4);
> +	bld_write(mux_o + DE_MUX_BLD_REGS, route, data);
> +
> +	bld_write(mux_o + DE_MUX_BLD_REGS, premultiply, 0);
> +	bld_write(mux_o + DE_MUX_BLD_REGS, bkcolor, 0xff000000);
> +	bld_write(mux_o + DE_MUX_BLD_REGS, bld_mode[0], 0x03010301);
> +								/* SRCOVER */
> +	bld_write(mux_o + DE_MUX_BLD_REGS, bld_mode[1], 0x03010301);
> +	bld_write(mux_o + DE_MUX_BLD_REGS, out_ctl, 0);
> +
> +	/* disable the enhancements */
> +	writel_relaxed(0, mux_o + DE_MUX_VSU_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_GSU1_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_GSU2_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_GSU3_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_FCE_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_BWS_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_LTI_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_PEAK_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_ASE_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_FCC_REGS);
> +	writel_relaxed(0, mux_o + DE_MUX_DCSC_REGS);
> +
> +	spin_unlock_irqrestore(&de_lock, flags);
> +}
> +
> +void de2_de_disable(struct priv *priv, int lcd_num)
> +{
> +	u32 data;
> +
> +	data = ~(1 << lcd_num);
> +	de_write(priv, DE_MOD_REG,
> +			de_read(priv, DE_MOD_REG) & data);
> +	de_write(priv, DE_GATE_REG,
> +			de_read(priv, DE_GATE_REG) & data);
> +	de_write(priv, DE_RESET_REG,
> +			de_read(priv, DE_RESET_REG) & data);
> +}
> +
> +int de2_de_init(struct priv *priv, struct device *dev)
> +{
> +	struct resource *res;
> +	int ret;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	res = platform_get_resource(to_platform_device(dev),
> +				IORESOURCE_MEM, 0);
> +	if (!res) {
> +		dev_err(dev, "failed to get memory resource\n");
> +		return -EINVAL;
> +	}
> +
> +	priv->mmio = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(priv->mmio)) {
> +		dev_err(dev, "failed to map registers\n");
> +		return PTR_ERR(priv->mmio);
> +	}
> +
> +	priv->gate = devm_clk_get(dev, "gate");	/* optional */

Error checking

> +
> +	priv->clk = devm_clk_get(dev, "clock");
> +	if (IS_ERR(priv->clk)) {
> +		dev_err(dev, "video clock err %d\n", (int) PTR_ERR(priv->clk));
> +		return PTR_ERR(priv->clk);
> +	}
> +
> +	priv->rstc = devm_reset_control_get_optional(dev, NULL);
> +
> +	if (!IS_ERR(priv->rstc)) {
> +		ret = reset_control_deassert(priv->rstc);
> +		if (ret) {
> +			dev_err(dev, "reset deassert err %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	if (!IS_ERR(priv->gate)) {
> +		ret = clk_prepare_enable(priv->gate);
> +		if (ret)
> +			goto err_gate;
> +	}
> +
> +	ret = clk_prepare_enable(priv->clk);
> +	if (ret)
> +		goto err_enable;
> +	if (priv->soc_type == SOC_A83T)
> +		clk_set_rate(priv->clk, DE_CLK_RATE_A83T);
> +	else
> +		clk_set_rate(priv->clk, DE_CLK_RATE_H3);
> +
> +	/* set the A83T clock divider = 500 / 250 */
> +	if (priv->soc_type == SOC_A83T)
> +		de_write(priv, DE_DIV_REG,
> +				0x00000011);	/* div = 2 for both LCDs */
> +
> +	return 0;
> +
> +err_enable:
> +	clk_disable_unprepare(priv->gate);
> +err_gate:
> +	if (!IS_ERR(priv->rstc))
> +		reset_control_assert(priv->rstc);
> +	return ret;
> +}
> +
> +void de2_de_cleanup(struct priv *priv)
> +{
> +	clk_disable_unprepare(priv->clk);
> +	clk_disable_unprepare(priv->gate);
> +	if (!IS_ERR(priv->rstc))
> +		reset_control_assert(priv->rstc);
> +}
> diff --git a/drivers/gpu/drm/sunxi/de2_drm.h b/drivers/gpu/drm/sunxi/de2_drm.h
> new file mode 100644
> index 0000000..7bb966c
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/de2_drm.h
> @@ -0,0 +1,47 @@
> +#ifndef __DE2_DRM_H__
> +#define __DE2_DRM_H__
> +/*
> + * Copyright (C) 2016 Jean-François Moine
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +#include <drm/drmP.h>
> +#include <drm/drm_fb_cma_helper.h>
> +
> +struct lcd;
> +
> +#define N_LCDS 2
> +
> +/* SoC types */
> +#define SOC_A83T 0
> +#define SOC_H3 1
> +
> +struct priv {
> +	void __iomem *mmio;
> +	struct clk *clk;
> +	struct clk *gate;
> +	struct reset_control *rstc;
> +
> +	int soc_type;
> +
> +	struct drm_fbdev_cma *fbdev;
> +
> +	struct lcd *lcds[N_LCDS];
> +};
> +
> +/* in de2_crtc.c */
> +int de2_enable_vblank(struct drm_device *drm, unsigned crtc);
> +void de2_disable_vblank(struct drm_device *drm, unsigned crtc);
> +extern struct platform_driver de2_lcd_platform_driver;
> +
> +/* in de2_de.c */
> +int de2_de_init(struct priv *priv, struct device *dev);
> +void de2_de_cleanup(struct priv *priv);
> +
> +#endif /* __DE2_DRM_H__ */
> diff --git a/drivers/gpu/drm/sunxi/de2_drv.c b/drivers/gpu/drm/sunxi/de2_drv.c
> new file mode 100644
> index 0000000..5daa15c
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/de2_drv.c
> @@ -0,0 +1,378 @@
> +/*
> + * Allwinner DRM driver - DE2 DRM driver
> + *
> + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/of_device.h>
> +#include <linux/of_graph.h>
> +#include <linux/component.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_gem_cma_helper.h>
> +
> +#include "de2_drm.h"
> +
> +#define DRIVER_NAME	"sunxi-de2"
> +#define DRIVER_DESC	"Allwinner DRM DE2"
> +#define DRIVER_DATE	"20161001"
> +#define DRIVER_MAJOR	1
> +#define DRIVER_MINOR	0
> +
> +static struct of_device_id de2_drm_of_match[] = {
> +	{ .compatible = "allwinner,sun8i-a83t-display-engine",
> +				.data = (void *) SOC_A83T },
> +	{ .compatible = "allwinner,sun8i-h3-display-engine",
> +				.data = (void *) SOC_H3 },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, de2_drm_of_match);
> +
> +static void de2_fb_output_poll_changed(struct drm_device *drm)
> +{
> +	struct priv *priv = drm->dev_private;
> +
> +	if (priv->fbdev)
> +		drm_fbdev_cma_hotplug_event(priv->fbdev);
> +}
> +
> +static const struct drm_mode_config_funcs de2_mode_config_funcs = {
> +	.fb_create = drm_fb_cma_create,
> +	.output_poll_changed = de2_fb_output_poll_changed,
> +	.atomic_check = drm_atomic_helper_check,
> +	.atomic_commit = drm_atomic_helper_commit,
> +};
> +
> +/*
> + * DRM operations:
> + */
> +static void de2_lastclose(struct drm_device *drm)
> +{
> +	struct priv *priv = drm->dev_private;
> +
> +	if (priv->fbdev)
> +		drm_fbdev_cma_restore_mode(priv->fbdev);
> +}
> +
> +static const struct file_operations de2_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= drm_open,
> +	.release	= drm_release,
> +	.unlocked_ioctl	= drm_ioctl,
> +	.poll		= drm_poll,
> +	.read		= drm_read,
> +	.llseek		= no_llseek,
> +	.mmap		= drm_gem_cma_mmap,
> +};
> +
> +static struct drm_driver de2_drm_driver = {
> +	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
> +					DRIVER_ATOMIC,
> +	.lastclose		= de2_lastclose,
> +	.get_vblank_counter	= drm_vblank_no_hw_counter,
> +	.enable_vblank		= de2_enable_vblank,
> +	.disable_vblank		= de2_disable_vblank,
> +	.gem_free_object	= drm_gem_cma_free_object,
> +	.gem_vm_ops		= &drm_gem_cma_vm_ops,
> +	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
> +	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
> +	.gem_prime_import	= drm_gem_prime_import,
> +	.gem_prime_export	= drm_gem_prime_export,
> +	.gem_prime_get_sg_table	= drm_gem_cma_prime_get_sg_table,
> +	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
> +	.gem_prime_vmap		= drm_gem_cma_prime_vmap,
> +	.gem_prime_vunmap	= drm_gem_cma_prime_vunmap,
> +	.gem_prime_mmap		= drm_gem_cma_prime_mmap,
> +	.dumb_create		= drm_gem_cma_dumb_create,
> +	.dumb_map_offset	= drm_gem_cma_dumb_map_offset,
> +	.dumb_destroy		= drm_gem_dumb_destroy,
> +	.fops			= &de2_fops,
> +	.name			= DRIVER_NAME,
> +	.desc			= DRIVER_DESC,
> +	.date			= DRIVER_DATE,
> +	.major			= DRIVER_MAJOR,
> +	.minor			= DRIVER_MINOR,
> +};
> +
> +#ifdef CONFIG_PM_SLEEP
> +/*
> + * Power management
> + */
> +static int de2_pm_suspend(struct device *dev)
> +{
> +	struct drm_device *drm = dev_get_drvdata(dev);
> +
> +	drm_kms_helper_poll_disable(drm);
> +	return 0;
> +}
> +
> +static int de2_pm_resume(struct device *dev)
> +{
> +	struct drm_device *drm = dev_get_drvdata(dev);
> +
> +	drm_kms_helper_poll_enable(drm);
> +	return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops de2_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(de2_pm_suspend, de2_pm_resume)
> +};

Why do you need that? How did you test it? There's no runtime_pm calls
in your kernel.

> +/*
> + * Platform driver
> + */
> +
> +static int de2_drm_bind(struct device *dev)
> +{
> +	struct drm_device *drm;
> +	struct priv *priv;
> +	int ret;
> +
> +	drm = drm_dev_alloc(&de2_drm_driver, dev);
> +	if (!drm)
> +		return -ENOMEM;
> +
> +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> +	if (!priv) {
> +		dev_err(dev, "failed to allocate private area\n");
> +		ret = -ENOMEM;
> +		goto out1;
> +	}
> +
> +	dev_set_drvdata(dev, drm);
> +	drm->dev_private = priv;
> +
> +	drm_mode_config_init(drm);
> +	drm->mode_config.min_width = 32;	/* needed for cursor */
> +	drm->mode_config.min_height = 32;
> +	drm->mode_config.max_width = 1920;
> +	drm->mode_config.max_height = 1080;
> +	drm->mode_config.funcs = &de2_mode_config_funcs;
> +
> +	drm->irq_enabled = true;
> +
> +	/* initialize the display engine */
> +	priv->soc_type = (int) of_match_device(de2_drm_of_match, dev)->data;
> +	ret = de2_de_init(priv, dev);
> +	if (ret)
> +		goto out2;
> +
> +	/* start the subdevices */
> +	ret = component_bind_all(dev, drm);
> +	if (ret < 0)
> +		goto out2;
> +
> +	ret = drm_dev_register(drm, 0);
> +	if (ret < 0)
> +		goto out3;
> +
> +	DRM_DEBUG_DRIVER("%d crtcs %d connectors\n",
> +			 drm->mode_config.num_crtc,
> +			 drm->mode_config.num_connector);
> +
> +	ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
> +	if (ret < 0)
> +		dev_warn(dev, "failed to initialize vblank\n");
> +
> +	drm_mode_config_reset(drm);
> +
> +	priv->fbdev = drm_fbdev_cma_init(drm,
> +					32,	/* bpp */
> +					drm->mode_config.num_crtc,
> +					drm->mode_config.num_connector);
> +	if (IS_ERR(priv->fbdev)) {
> +		ret = PTR_ERR(priv->fbdev);
> +		priv->fbdev = NULL;
> +		goto out4;
> +	}
> +
> +	drm_kms_helper_poll_init(drm);
> +
> +	return 0;
> +
> +out4:
> +	drm_dev_unregister(drm);
> +out3:
> +	component_unbind_all(dev, drm);
> +out2:
> +	kfree(priv);
> +out1:
> +	drm_dev_unref(drm);
> +	return ret;
> +}
> +
> +static void de2_drm_unbind(struct device *dev)
> +{
> +	struct drm_device *drm = dev_get_drvdata(dev);
> +	struct priv *priv = drm->dev_private;
> +
> +	if (priv)
> +		drm_fbdev_cma_fini(priv->fbdev);
> +	drm_kms_helper_poll_fini(drm);
> +
> +	drm_dev_unregister(drm);
> +	drm_vblank_cleanup(drm);
> +
> +	drm_mode_config_cleanup(drm);
> +
> +	component_unbind_all(dev, drm);
> +
> +	if (priv) {
> +		de2_de_cleanup(priv);
> +		kfree(priv);
> +	}
> +
> +	drm_dev_unref(drm);
> +}
> +
> +static const struct component_master_ops de2_drm_comp_ops = {
> +	.bind = de2_drm_bind,
> +	.unbind = de2_drm_unbind,
> +};
> +
> +static int compare_of(struct device *dev, void *data)
> +{
> +	return dev->of_node == data;
> +}
> +
> +static int de2_drm_add_components(struct device *dev,
> +				  int (*compare_of)(struct device *, void *),
> +				  const struct component_master_ops *m_ops)
> +{
> +	struct device_node *ep, *port, *remote;
> +	struct component_match *match = NULL;
> +	int i;
> +
> +	if (!dev->of_node)
> +		return -EINVAL;
> +
> +	/* bind the CRTCs */
> +	for (i = 0; ; i++) {
> +		port = of_parse_phandle(dev->of_node, "ports", i);
> +		if (!port)
> +			break;
> +
> +		if (!of_device_is_available(port->parent)) {
> +			of_node_put(port);
> +			continue;
> +		}
> +
> +		component_match_add(dev, &match, compare_of, port->parent);
> +		of_node_put(port);
> +	}
> +
> +	if (i == 0) {
> +		dev_err(dev, "missing 'ports' property\n");
> +		return -ENODEV;
> +	}
> +	if (!match) {
> +		dev_err(dev, "no available port\n");
> +		return -ENODEV;
> +	}
> +
> +	/* bind the encoders/connectors */
> +	for (i = 0; ; i++) {
> +		port = of_parse_phandle(dev->of_node, "ports", i);
> +		if (!port)
> +			break;
> +
> +		if (!of_device_is_available(port->parent)) {
> +			of_node_put(port);
> +			continue;
> +		}
> +
> +		for_each_child_of_node(port, ep) {
> +			remote = of_graph_get_remote_port_parent(ep);
> +			if (!remote || !of_device_is_available(remote)) {
> +				of_node_put(remote);
> +				continue;
> +			}
> +			if (!of_device_is_available(remote->parent)) {
> +				dev_warn(dev,
> +					"parent device of %s is not available\n",
> +					remote->full_name);
> +				of_node_put(remote);
> +				continue;
> +			}
> +
> +			component_match_add(dev, &match, compare_of, remote);
> +			of_node_put(remote);
> +		}
> +		of_node_put(port);
> +	}
> +
> +	return component_master_add_with_match(dev, m_ops, match);
> +}
> +
> +static int de2_drm_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +
> +	ret = de2_drm_add_components(&pdev->dev,
> +				     compare_of,
> +				     &de2_drm_comp_ops);
> +	if (ret == -EINVAL)
> +		ret = -ENXIO;
> +	return ret;
> +}
> +
> +static int de2_drm_remove(struct platform_device *pdev)
> +{
> +	component_master_del(&pdev->dev, &de2_drm_comp_ops);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver de2_drm_platform_driver = {
> +	.probe      = de2_drm_probe,
> +	.remove     = de2_drm_remove,
> +	.driver     = {
> +		.name = DRIVER_NAME,
> +		.pm = &de2_pm_ops,
> +		.of_match_table = de2_drm_of_match,
> +	},
> +};
> +
> +static int __init de2_drm_init(void)
> +{
> +	int ret;
> +
> +/* uncomment to activate the drm traces at startup time */
> +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> +			DRM_UT_PRIME | DRM_UT_ATOMIC; */

That's useless.

> +	DRM_DEBUG_DRIVER("\n");
> +
> +	ret = platform_driver_register(&de2_lcd_platform_driver);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = platform_driver_register(&de2_drm_platform_driver);
> +	if (ret < 0)
> +		platform_driver_unregister(&de2_lcd_platform_driver);
> +
> +	return ret;
> +}

And that really shouldn't be done that way.

> +static void __exit de2_drm_fini(void)
> +{
> +	platform_driver_unregister(&de2_lcd_platform_driver);
> +	platform_driver_unregister(&de2_drm_platform_driver);
> +}
> +
> +module_init(de2_drm_init);
> +module_exit(de2_drm_fini);
> +
> +MODULE_AUTHOR("Jean-Francois Moine <moinejf@free.fr>");
> +MODULE_DESCRIPTION("Allwinner DE2 DRM Driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/gpu/drm/sunxi/de2_plane.c b/drivers/gpu/drm/sunxi/de2_plane.c
> new file mode 100644
> index 0000000..b338684
> --- /dev/null
> +++ b/drivers/gpu/drm/sunxi/de2_plane.c
> @@ -0,0 +1,119 @@
> +/*
> + * Allwinner DRM driver - DE2 planes
> + *
> + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_plane_helper.h>
> +#include <drm/drm_crtc_helper.h>
> +
> +#include "de2_drm.h"
> +#include "de2_crtc.h"
> +
> +/* plane formats */
> +static const uint32_t ui_formats[] = {
> +	DRM_FORMAT_ARGB8888,
> +	DRM_FORMAT_BGRA8888,
> +	DRM_FORMAT_XRGB8888,
> +	DRM_FORMAT_RGB888,
> +	DRM_FORMAT_BGR888,
> +};
> +
> +static const uint32_t vi_formats[] = {
> +	DRM_FORMAT_XRGB8888,
> +	DRM_FORMAT_YUYV,
> +	DRM_FORMAT_YVYU,
> +	DRM_FORMAT_YUV422,
> +	DRM_FORMAT_YUV420,
> +	DRM_FORMAT_UYVY,
> +	DRM_FORMAT_BGRA8888,
> +	DRM_FORMAT_RGB888,
> +	DRM_FORMAT_BGR888,
> +};
> +
> +static void de2_plane_disable(struct drm_plane *plane,
> +				struct drm_plane_state *old_state)
> +{
> +	struct drm_crtc *crtc = old_state->crtc;
> +	struct lcd *lcd = crtc_to_lcd(crtc);
> +	int plane_num = plane - lcd->planes;
> +
> +	de2_de_plane_disable(lcd->priv, lcd->num, plane_num);
> +}
> +
> +static void de2_plane_update(struct drm_plane *plane,
> +				struct drm_plane_state *old_state)
> +{
> +	struct drm_plane_state *state = plane->state;
> +	struct drm_crtc *crtc = state->crtc;
> +	struct lcd *lcd = crtc_to_lcd(crtc);
> +	struct drm_framebuffer *fb = state->fb;
> +	int plane_num = plane - lcd->planes;
> +
> +	if (!crtc || !fb) {
> +		DRM_DEBUG_DRIVER("no crtc/fb\n");
> +		return;
> +	}
> +
> +	de2_de_plane_update(lcd->priv, lcd->num, plane_num,
> +			    state, old_state);
> +}
> +
> +static const struct drm_plane_helper_funcs plane_helper_funcs = {
> +	.atomic_disable = de2_plane_disable,
> +	.atomic_update = de2_plane_update,
> +};
> +
> +static const struct drm_plane_funcs plane_funcs = {
> +	.update_plane = drm_atomic_helper_update_plane,
> +	.disable_plane = drm_atomic_helper_disable_plane,
> +	.destroy = drm_plane_cleanup,
> +	.reset = drm_atomic_helper_plane_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
> +};
> +
> +static int de2_one_plane_init(struct drm_device *drm,
> +				struct drm_plane *plane,
> +				int type, int possible_crtcs,
> +				const uint32_t *formats,
> +				int nformats)
> +{
> +	int ret;
> +
> +	ret = drm_universal_plane_init(drm, plane, possible_crtcs,
> +				&plane_funcs,
> +				formats, nformats, type, NULL);
> +	if (ret >= 0)
> +		drm_plane_helper_add(plane, &plane_helper_funcs);
> +
> +	return ret;
> +}
> +
> +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> +{
> +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> +
> +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> +				ui_formats, ARRAY_SIZE(ui_formats));
> +	if (ret >= 0)
> +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> +				ui_formats, ARRAY_SIZE(ui_formats));

Nothing looks really special about that cursor plane. Any reasion not
to make it an overlay?

Maxime
Daniel Vetter Oct. 25, 2016, 6:44 a.m. UTC | #2
On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
> +static int de2_drm_bind(struct device *dev)
> +{
> +	struct drm_device *drm;
> +	struct priv *priv;
> +	int ret;
> +
> +	drm = drm_dev_alloc(&de2_drm_driver, dev);
> +	if (!drm)
> +		return -ENOMEM;
> +
> +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> +	if (!priv) {
> +		dev_err(dev, "failed to allocate private area\n");
> +		ret = -ENOMEM;
> +		goto out1;
> +	}
> +
> +	dev_set_drvdata(dev, drm);
> +	drm->dev_private = priv;
> +
> +	drm_mode_config_init(drm);
> +	drm->mode_config.min_width = 32;	/* needed for cursor */
> +	drm->mode_config.min_height = 32;
> +	drm->mode_config.max_width = 1920;
> +	drm->mode_config.max_height = 1080;
> +	drm->mode_config.funcs = &de2_mode_config_funcs;
> +
> +	drm->irq_enabled = true;
> +
> +	/* initialize the display engine */
> +	priv->soc_type = (int) of_match_device(de2_drm_of_match, dev)->data;
> +	ret = de2_de_init(priv, dev);
> +	if (ret)
> +		goto out2;
> +
> +	/* start the subdevices */
> +	ret = component_bind_all(dev, drm);
> +	if (ret < 0)
> +		goto out2;
> +
> +	ret = drm_dev_register(drm, 0);

This needs to be the very last step in your driver load sequence.
Kerneldoc explains why. Similar, but inverted for unloading:
drm_dev_unregister is the very first thing you must call.
-Daniel
Daniel Vetter Oct. 25, 2016, 6:46 a.m. UTC | #3
On Tue, Oct 25, 2016 at 08:44:22AM +0200, Daniel Vetter wrote:
> On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
> > +static int de2_drm_bind(struct device *dev)
> > +{
> > +	struct drm_device *drm;
> > +	struct priv *priv;
> > +	int ret;
> > +
> > +	drm = drm_dev_alloc(&de2_drm_driver, dev);

Oh and you might want to look into drm_dev_init, allows you to use
subclassing instead of pointer chasing for your driver-private data.
-Daniel

> > +	if (!drm)
> > +		return -ENOMEM;
> > +
> > +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > +	if (!priv) {
> > +		dev_err(dev, "failed to allocate private area\n");
> > +		ret = -ENOMEM;
> > +		goto out1;
> > +	}
> > +
> > +	dev_set_drvdata(dev, drm);
> > +	drm->dev_private = priv;
> > +
> > +	drm_mode_config_init(drm);
> > +	drm->mode_config.min_width = 32;	/* needed for cursor */
> > +	drm->mode_config.min_height = 32;
> > +	drm->mode_config.max_width = 1920;
> > +	drm->mode_config.max_height = 1080;
> > +	drm->mode_config.funcs = &de2_mode_config_funcs;
> > +
> > +	drm->irq_enabled = true;
> > +
> > +	/* initialize the display engine */
> > +	priv->soc_type = (int) of_match_device(de2_drm_of_match, dev)->data;
> > +	ret = de2_de_init(priv, dev);
> > +	if (ret)
> > +		goto out2;
> > +
> > +	/* start the subdevices */
> > +	ret = component_bind_all(dev, drm);
> > +	if (ret < 0)
> > +		goto out2;
> > +
> > +	ret = drm_dev_register(drm, 0);
> 
> This needs to be the very last step in your driver load sequence.
> Kerneldoc explains why. Similar, but inverted for unloading:
> drm_dev_unregister is the very first thing you must call.
> -Daniel
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
Jean-Francois Moine Oct. 25, 2016, 2:14 p.m. UTC | #4
On Mon, 24 Oct 2016 16:04:19 +0200
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> Hi,

Hi Maxime,

> On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
> > Allwinner's recent SoCs, as A64, A83T and H3, contain a new display
> > engine, DE2.
> > This patch adds a DRM video driver for this device.
> > 
> > Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
> 
> Output from checkpatch:
> total: 0 errors, 20 warnings, 83 checks, 1799 lines checked
> 
> > ---
> >  .../bindings/display/sunxi/sunxi-de2.txt           |  83 +++
> >  drivers/gpu/drm/Kconfig                            |   2 +
> >  drivers/gpu/drm/Makefile                           |   1 +
> >  drivers/gpu/drm/sunxi/Kconfig                      |  21 +
> >  drivers/gpu/drm/sunxi/Makefile                     |   7 +
> >  drivers/gpu/drm/sunxi/de2_crtc.c                   | 475 +++++++++++++++++
> >  drivers/gpu/drm/sunxi/de2_crtc.h                   |  63 +++
> >  drivers/gpu/drm/sunxi/de2_de.c                     | 591 +++++++++++++++++++++
> >  drivers/gpu/drm/sunxi/de2_drm.h                    |  47 ++
> >  drivers/gpu/drm/sunxi/de2_drv.c                    | 378 +++++++++++++
> >  drivers/gpu/drm/sunxi/de2_plane.c                  | 119 +++++
> >  11 files changed, 1787 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> >  create mode 100644 drivers/gpu/drm/sunxi/Kconfig
> >  create mode 100644 drivers/gpu/drm/sunxi/Makefile
> >  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.c
> >  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.h
> >  create mode 100644 drivers/gpu/drm/sunxi/de2_de.c
> >  create mode 100644 drivers/gpu/drm/sunxi/de2_drm.h
> >  create mode 100644 drivers/gpu/drm/sunxi/de2_drv.c
> >  create mode 100644 drivers/gpu/drm/sunxi/de2_plane.c
> > 
> > diff --git a/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> > new file mode 100644
> > index 0000000..f9cd67a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> > @@ -0,0 +1,83 @@
> > +Allwinner sunxi Display Engine 2 subsystem
> > +==========================================
> > +
> > +The sunxi DE2 subsystem contains a display controller (DE2),
> 
> sunxi is a made up name, and doesn't really mean anything. You can
> call it either sun8i (because it was introduced in that family).

OK.

> > +one or two LCD controllers (TCON) and their external interfaces.
> > +
> > +Display controller
> > +==================
> > +
> > +Required properties:
> > +
> > +- compatible: value should be one of the following
> > +		"allwinner,sun8i-a83t-display-engine"
> > +		"allwinner,sun8i-h3-display-engine"
> > +
> > +- clocks: must include clock specifiers corresponding to entries in the
> > +		clock-names property.
> > +
> > +- clock-names: must contain
> > +		"gate": for DE activation
> > +		"clock": DE clock
> 
> We've been calling them bus and mod.

I can understand "bus" (which is better than "apb"), but why "mod"?

> > +
> > +- resets: phandle to the reset of the device
> > +
> > +- ports: phandle's to the LCD ports
> 
> Please use the OF graph.

These ports are references to the graph of nodes. See
	http://www.kernelhub.org/?msg=911825&p=2

	[snip]
> > diff --git a/drivers/gpu/drm/sunxi/de2_crtc.c b/drivers/gpu/drm/sunxi/de2_crtc.c
> > new file mode 100644
> > index 0000000..dae0fab
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sunxi/de2_crtc.c
> > @@ -0,0 +1,475 @@
> > +/*
> > + * Allwinner DRM driver - DE2 CRTC
> > + *
> > + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License as
> > + * published by the Free Software Foundation; either version 2 of
> > + * the License, or (at your option) any later version.
> > + */
> > +
> > +#include <linux/component.h>
> > +#include <drm/drm_crtc_helper.h>
> > +#include <drm/drm_atomic_helper.h>
> > +#include <asm/io.h>
> > +#include <linux/of_irq.h>
> > +
> > +#include "de2_drm.h"
> > +#include "de2_crtc.h"
> > +
> > +/* I/O map */
> > +
> > +struct tcon {
> > +	u32 gctl;
> > +#define		TCON_GCTL_TCON_En BIT(31)
> > +	u32 gint0;
> > +#define		TCON_GINT0_TCON1_Vb_Int_En BIT(30)
> > +#define		TCON_GINT0_TCON1_Vb_Int_Flag BIT(14)
> > +	u32 gint1;
> > +	u32 dum0[13];
> > +	u32 tcon0_ctl;				/* 0x40 */
> > +#define		TCON0_CTL_TCON_En BIT(31)
> > +	u32 dum1[19];
> > +	u32 tcon1_ctl;				/* 0x90 */
> > +#define		TCON1_CTL_TCON_En BIT(31)
> > +#define		TCON1_CTL_Interlace_En BIT(20)
> > +#define		TCON1_CTL_Start_Delay_SHIFT 4
> > +#define		TCON1_CTL_Start_Delay_MASK GENMASK(8, 4)
> > +	u32 basic0;			/* XI/YI */
> > +	u32 basic1;			/* LS_XO/LS_YO */
> > +	u32 basic2;			/* XO/YO */
> > +	u32 basic3;			/* HT/HBP */
> > +	u32 basic4;			/* VT/VBP */
> > +	u32 basic5;			/* HSPW/VSPW */
> > +	u32 dum2;
> > +	u32 ps_sync;				/* 0xb0 */
> > +	u32 dum3[15];
> > +	u32 io_pol;				/* 0xf0 */
> > +#define		TCON1_IO_POL_IO0_inv BIT(24)
> > +#define		TCON1_IO_POL_IO1_inv BIT(25)
> > +#define		TCON1_IO_POL_IO2_inv BIT(26)
> > +	u32 io_tri;
> > +	u32 dum4[2];
> > +
> > +	u32 ceu_ctl;				/* 0x100 */
> > +#define     TCON_CEU_CTL_ceu_en BIT(31)
> > +	u32 dum5[3];
> > +	u32 ceu_rr;
> > +	u32 ceu_rg;
> > +	u32 ceu_rb;
> > +	u32 ceu_rc;
> > +	u32 ceu_gr;
> > +	u32 ceu_gg;
> > +	u32 ceu_gb;
> > +	u32 ceu_gc;
> > +	u32 ceu_br;
> > +	u32 ceu_bg;
> > +	u32 ceu_bb;
> > +	u32 ceu_bc;
> > +	u32 ceu_rv;
> > +	u32 ceu_gv;
> > +	u32 ceu_bv;
> > +	u32 dum6[45];
> > +
> > +	u32 mux_ctl;				/* 0x200 */
> > +	u32 dum7[63];
> > +
> > +	u32 fill_ctl;				/* 0x300 */
> > +	u32 fill_start0;
> > +	u32 fill_end0;
> > +	u32 fill_data0;
> > +};
> 
> Please use defines instead of the structures.

I think that structures are more readable.

> > +
> > +#define XY(x, y) (((x) << 16) | (y))
> > +
> > +#define tcon_read(base, member) \
> > +	readl_relaxed(base + offsetof(struct tcon, member))
> > +#define tcon_write(base, member, data) \
> > +	writel_relaxed(data, base + offsetof(struct tcon, member))
> > +
> > +/* vertical blank functions */
> > +static void de2_atomic_flush(struct drm_crtc *crtc,
> > +			struct drm_crtc_state *old_state)
> > +{
> > +	struct drm_pending_vblank_event *event = crtc->state->event;
> > +
> > +	if (event) {
> > +		crtc->state->event = NULL;
> > +		spin_lock_irq(&crtc->dev->event_lock);
> > +		if (drm_crtc_vblank_get(crtc) == 0)
> > +			drm_crtc_arm_vblank_event(crtc, event);
> > +		else
> > +			drm_crtc_send_vblank_event(crtc, event);
> > +		spin_unlock_irq(&crtc->dev->event_lock);
> > +	}
> > +}
> > +
> > +static irqreturn_t de2_lcd_irq(int irq, void *dev_id)
> > +{
> > +	struct lcd *lcd = (struct lcd *) dev_id;
> > +	u32 isr;
> > +
> > +	isr = tcon_read(lcd->mmio, gint0);
> > +
> > +	drm_crtc_handle_vblank(&lcd->crtc);
> > +
> > +	tcon_write(lcd->mmio, gint0, isr & ~TCON_GINT0_TCON1_Vb_Int_Flag);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +int de2_enable_vblank(struct drm_device *drm, unsigned crtc)
> > +{
> > +	struct priv *priv = drm->dev_private;
> > +	struct lcd *lcd = priv->lcds[crtc];
> > +
> > +	tcon_write(lcd->mmio, gint0,
> > +			tcon_read(lcd->mmio, gint0) |
> > +					TCON_GINT0_TCON1_Vb_Int_En);
> 
> That's a weird indentation
> 
> > +	return 0;
> > +}
> > +
> > +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> > +{
> > +	struct priv *priv = drm->dev_private;
> > +	struct lcd *lcd = priv->lcds[crtc];
> > +
> > +	tcon_write(lcd->mmio, gint0,
> > +			 tcon_read(lcd->mmio, gint0) &
> > +					~TCON_GINT0_TCON1_Vb_Int_En);
> > +}
> > +
> > +/* panel functions */
> 
> Panel functions? In the CRTC driver?

Yes, dumb panel.

> > +static void de2_set_frame_timings(struct lcd *lcd)
> > +{
> > +	struct drm_crtc *crtc = &lcd->crtc;
> > +	const struct drm_display_mode *mode = &crtc->mode;
> > +	int interlace = mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 1;
> > +	int start_delay;
> > +	u32 data;
> > +
> > +	data = XY(mode->hdisplay - 1, mode->vdisplay / interlace - 1);
> > +	tcon_write(lcd->mmio, basic0, data);
> > +	tcon_write(lcd->mmio, basic1, data);
> > +	tcon_write(lcd->mmio, basic2, data);
> > +	tcon_write(lcd->mmio, basic3,
> > +			XY(mode->htotal - 1,
> > +				mode->htotal - mode->hsync_start - 1));
> > +	tcon_write(lcd->mmio, basic4,
> > +			XY(mode->vtotal * (3 - interlace),
> > +				mode->vtotal - mode->vsync_start - 1));
> > +	tcon_write(lcd->mmio, basic5,
> > +			 XY(mode->hsync_end - mode->hsync_start - 1,
> > +				mode->vsync_end - mode->vsync_start - 1));
> > +
> > +	tcon_write(lcd->mmio, ps_sync, XY(1, 1));
> > +
> > +	data = TCON1_IO_POL_IO2_inv;
> > +	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
> > +		data |= TCON1_IO_POL_IO0_inv;
> > +	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
> > +		data |= TCON1_IO_POL_IO1_inv;
> > +	tcon_write(lcd->mmio, io_pol, data);
> > +
> > +	tcon_write(lcd->mmio, ceu_ctl,
> > +		tcon_read(lcd->mmio, ceu_ctl) & ~TCON_CEU_CTL_ceu_en);
> > +
> > +	data = tcon_read(lcd->mmio, tcon1_ctl);
> > +	if (interlace == 2)
> > +		data |= TCON1_CTL_Interlace_En;
> > +	else
> > +		data &= ~TCON1_CTL_Interlace_En;
> > +	tcon_write(lcd->mmio, tcon1_ctl, data);
> > +
> > +	tcon_write(lcd->mmio, fill_ctl, 0);
> > +	tcon_write(lcd->mmio, fill_start0, mode->vtotal + 1);
> > +	tcon_write(lcd->mmio, fill_end0, mode->vtotal);
> > +	tcon_write(lcd->mmio, fill_data0, 0);
> > +
> > +	start_delay = (mode->vtotal - mode->vdisplay) / interlace - 5;
> > +	if (start_delay > 31)
> > +		start_delay = 31;
> > +	data = tcon_read(lcd->mmio, tcon1_ctl);
> > +	data &= ~TCON1_CTL_Start_Delay_MASK;
> > +	data |= start_delay << TCON1_CTL_Start_Delay_SHIFT;
> > +	tcon_write(lcd->mmio, tcon1_ctl, data);
> > +
> > +	tcon_write(lcd->mmio, io_tri, 0x0fffffff);
> > +}
> 
> Some comments here would be nice, there's a lot of non trivial things.

... and no documentation. I just set the values I saw in the I/O memory
when running the legacy driver.

> > +
> > +static void de2_crtc_enable(struct drm_crtc *crtc)
> > +{
> > +	struct lcd *lcd = crtc_to_lcd(crtc);
> > +	struct drm_display_mode *mode = &crtc->mode;
> > +
> > +	DRM_DEBUG_DRIVER("\n");
> 
> Log something useful, or don't.

This was useful when the driver was crashing only God knew where.

> > +
> > +	clk_set_rate(lcd->clk, mode->clock * 1000);
> > +
> > +	de2_set_frame_timings(lcd);
> > +
> > +	tcon_write(lcd->mmio, tcon1_ctl,
> > +		tcon_read(lcd->mmio, tcon1_ctl) | TCON1_CTL_TCON_En);
> > +
> > +	de2_de_panel_init(lcd->priv, lcd->num, mode);
> 
> panel_init in the CRTC enable? Shouldn't that be in the panel driver?
> or at least the encoder?

I will change to 'dumb panel'.

> > +
> > +	drm_mode_debug_printmodeline(mode);
> 
> This is already printed by the core.

Not at this time.

	[snip]
> > +static int de2_lcd_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev->of_node, *tmp, *parent, *port;
> > +	struct lcd *lcd;
> > +	struct resource *res;
> > +	int id, irq, ret;
> > +
> > +	id = of_alias_get_id(np, "lcd");
> > +	if (id < 0) {
> > +		dev_err(dev, "no alias for lcd\n");
> > +		id = 0;
> > +	}
> > +	lcd = devm_kzalloc(dev, sizeof *lcd, GFP_KERNEL);
> > +	if (!lcd) {
> > +		dev_err(dev, "failed to allocate private data\n");
> > +		return -ENOMEM;
> > +	}
> > +	dev_set_drvdata(dev, lcd);
> > +	lcd->dev = dev;
> > +	lcd->num = id;
> 
> What do you need this number for?

It permits access to the overlay planes in the DE2.

> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	if (!res) {
> > +		dev_err(dev, "failed to get memory resource\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	lcd->mmio = devm_ioremap_resource(dev, res);
> > +	if (IS_ERR(lcd->mmio)) {
> > +		dev_err(dev, "failed to map registers\n");
> > +		return PTR_ERR(lcd->mmio);
> > +	}
> > +
> > +	snprintf(lcd->name, sizeof(lcd->name), "sunxi-lcd%d", id);
> > +
> > +	/* possible CRTCs */
> > +	parent = np;
> > +	tmp = of_get_child_by_name(np, "ports");
> > +	if (tmp)
> > +		parent = tmp;
> > +	port = of_get_child_by_name(parent, "port");
> > +	of_node_put(tmp);
> > +	if (!port) {
> > +		dev_err(dev, "no port node\n");
> > +		return -ENXIO;
> > +	}
> > +	lcd->crtc.port = port;
> > +
> > +	lcd->gate = devm_clk_get(dev, "gate");		/* optional */
> 
> Having some kind of error checking would still be nice.

And cancel the device creation?

> > +
> > +	lcd->clk = devm_clk_get(dev, "clock");
> > +	if (IS_ERR(lcd->clk)) {
> > +		dev_err(dev, "video clock err %d\n", (int) PTR_ERR(lcd->clk));
> > +		ret = PTR_ERR(lcd->clk);
> > +		goto err;
> > +	}
> > +
> > +	lcd->rstc = devm_reset_control_get_optional(dev, NULL);
> 
> Ditto.
> 
> > +
> > +	irq = irq_of_parse_and_map(np, 0);
> > +	if (irq <= 0 || irq == NO_IRQ) {
> > +		dev_err(dev, "unable to get irq lcd %d\n", id);
> > +		ret = -EINVAL;
> > +		goto err;
> > +	}
> 
> You can use platform_get_irq for that.

Right. Thanks.

> > +
> > +	if (!IS_ERR(lcd->rstc)) {
> > +		ret = reset_control_deassert(lcd->rstc);
> > +		if (ret) {
> > +			dev_err(dev, "reset deassert err %d\n", ret);
> > +			goto err;
> > +		}
> > +	}
> > +
> > +	if (!IS_ERR(lcd->gate)) {
> > +		ret = clk_prepare_enable(lcd->gate);
> > +		if (ret)
> > +			goto err2;
> > +	}
> > +
> > +	ret = clk_prepare_enable(lcd->clk);
> > +	if (ret)
> > +		goto err2;
> 
> Is there any reason not to do that in the enable / disable? Leaving
> clocks running while the device has no guarantee that it's going to be
> used seems like a waste of resources.

If the machine does not need video (network server, router..), it is simpler
to prevent the video driver to be loaded (DT, module black list...).

> > +
> > +	de2_tcon_init(lcd);
> > +
> > +	ret = devm_request_irq(dev, irq, de2_lcd_irq, 0,
> > +				lcd->name, lcd);
> > +	if (ret < 0) {
> > +		dev_err(dev, "unable to request irq %d\n", irq);
> > +		goto err2;
> > +	}
> > +
> > +	return component_add(dev, &de2_lcd_ops);
> > +
> > +err2:
> > +	if (!IS_ERR_OR_NULL(lcd->rstc))
> > +		reset_control_assert(lcd->rstc);
> > +	clk_disable_unprepare(lcd->gate);
> > +	clk_disable_unprepare(lcd->clk);
> > +err:
> > +	of_node_put(lcd->crtc.port);
> > +	return ret;
> > +}
> > +
> > +static int de2_lcd_remove(struct platform_device *pdev)
> > +{
> > +	struct lcd *lcd = platform_get_drvdata(pdev);
> > +
> > +	component_del(&pdev->dev, &de2_lcd_ops);
> > +
> > +	if (!IS_ERR_OR_NULL(lcd->rstc))
> > +		reset_control_assert(lcd->rstc);
> > +	clk_disable_unprepare(lcd->gate);
> > +	clk_disable_unprepare(lcd->clk);
> > +	of_node_put(lcd->crtc.port);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id de2_lcd_ids[] = {
> > +	{ .compatible = "allwinner,sun8i-a83t-lcd", },
> > +	{ }
> > +};
> > +
> > +struct platform_driver de2_lcd_platform_driver = {
> > +	.probe = de2_lcd_probe,
> > +	.remove = de2_lcd_remove,
> > +	.driver = {
> > +		.name = "sunxi-de2-lcd",
> > +		.of_match_table = of_match_ptr(de2_lcd_ids),
> > +	},
> > +};
> > diff --git a/drivers/gpu/drm/sunxi/de2_crtc.h b/drivers/gpu/drm/sunxi/de2_crtc.h
> > new file mode 100644
> > index 0000000..efbe45d
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sunxi/de2_crtc.h
> > @@ -0,0 +1,63 @@
> > +#ifndef __DE2_CRTC_H__
> > +#define __DE2_CRTC_H__
> > +/*
> > + * Copyright (C) 2016 Jean-François Moine
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License as
> > + * published by the Free Software Foundation; either version 2 of
> > + * the License, or (at your option) any later version.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/reset.h>
> > +#include <drm/drm_plane_helper.h>
> > +
> > +struct priv;
> > +
> > +enum de2_plane2 {
> > +	DE2_PRIMARY_PLANE,
> > +	DE2_CURSOR_PLANE,
> > +	DE2_VI_PLANE,
> > +	DE2_N_PLANES,
> > +};
> > +struct lcd {
> > +	void __iomem *mmio;
> > +
> > +	struct device *dev;
> > +	struct drm_crtc crtc;
> > +	struct priv *priv;	/* DRM/DE private data */
> > +
> > +	short num;		/* LCD number in hardware */
> > +	short crtc_idx;		/* CRTC index in drm */
> > +
> > +	struct clk *clk;
> > +	struct clk *gate;
> > +	struct reset_control *rstc;
> > +
> > +	char name[16];
> > +
> > +	struct drm_pending_vblank_event *event;
> > +
> > +	struct drm_plane planes[DE2_N_PLANES];
> > +};
> > +
> > +#define crtc_to_lcd(x) container_of(x, struct lcd, crtc)
> > +
> > +/* in de2_de.c */
> > +void de2_de_enable(struct priv *priv, int lcd_num);
> > +void de2_de_disable(struct priv *priv, int lcd_num);
> > +void de2_de_hw_init(struct priv *priv, int lcd_num);
> > +void de2_de_panel_init(struct priv *priv, int lcd_num,
> > +			struct drm_display_mode *mode);
> > +void de2_de_plane_disable(struct priv *priv,
> > +			int lcd_num, int plane_ix);
> > +void de2_de_plane_update(struct priv *priv,
> > +			int lcd_num, int plane_ix,
> > +			struct drm_plane_state *state,
> > +			struct drm_plane_state *old_state);
> 
> Does it need to be exported?

I don't understand the question.

> > +
> > +/* in de2_plane.c */
> > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd);
> > +
> > +#endif /* __DE2_CRTC_H__ */
> > diff --git a/drivers/gpu/drm/sunxi/de2_de.c b/drivers/gpu/drm/sunxi/de2_de.c
> > new file mode 100644
> > index 0000000..0d8cb62
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sunxi/de2_de.c
> > @@ -0,0 +1,591 @@
> > +/*
> > + * ALLWINNER DRM driver - Display Engine 2
> > + *
> > + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> > + * Copyright (c) 2016 Allwinnertech Co., Ltd.
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License as
> > + * published by the Free Software Foundation; either version 2 of
> > + * the License, or (at your option) any later version.
> > + */
> > +
> > +#include <asm/io.h>
> > +#include <drm/drm_gem_cma_helper.h>
> > +
> > +#include "de2_drm.h"
> > +#include "de2_crtc.h"
> > +
> > +static DEFINE_SPINLOCK(de_lock);
> > +
> > +#define DE_CLK_RATE_A83T 504000000	/* pll-de */
> > +#define DE_CLK_RATE_H3 432000000	/* de */
> 
> This can be set in the DT.

That's what I had in first releases, but, recently, I saw a 'set
parent' code in a clock driver, because 'it is not the plan to expose'
some clocks in the DT. I am glad to move these clock rate settings
back to the DT.

> > +
> > +/* I/O map */
> > +
> > +#define DE_MOD_REG 0x0000	/* 1 bit per LCD */
> > +#define DE_GATE_REG 0x0004
> > +#define DE_RESET_REG 0x0008
> > +#define DE_DIV_REG 0x000c	/* 4 bits per LCD */
> > +#define DE_SEL_REG 0x0010
> > +
> > +#define DE_MUX0_BASE 0x00100000
> > +#define DE_MUX1_BASE 0x00200000
> > +
> > +/* MUX registers (addr / MUX base) */
> > +#define DE_MUX_GLB_REGS 0x00000		/* global control */
> > +#define DE_MUX_BLD_REGS 0x01000		/* alpha blending */
> > +#define DE_MUX_CHAN_REGS 0x02000	/* VI/UI overlay channels */
> > +#define		DE_MUX_CHAN_SZ 0x1000	/* size of a channel */
> > +#define DE_MUX_VSU_REGS 0x20000		/* VSU */
> > +#define DE_MUX_GSU1_REGS 0x30000	/* GSUs */
> > +#define DE_MUX_GSU2_REGS 0x40000
> > +#define DE_MUX_GSU3_REGS 0x50000
> > +#define DE_MUX_FCE_REGS 0xa0000		/* FCE */
> > +#define DE_MUX_BWS_REGS 0xa2000		/* BWS */
> > +#define DE_MUX_LTI_REGS 0xa4000		/* LTI */
> > +#define DE_MUX_PEAK_REGS 0xa6000	/* PEAK */
> > +#define DE_MUX_ASE_REGS 0xa8000		/* ASE */
> > +#define DE_MUX_FCC_REGS 0xaa000		/* FCC */
> > +#define DE_MUX_DCSC_REGS 0xb0000	/* DCSC/SMBL */
> > +
> > +/* global control */
> > +struct de_glb {
> > +	u32 ctl;
> > +#define		DE_MUX_GLB_CTL_rt_en BIT(0)
> > +#define		DE_MUX_GLB_CTL_finish_irq_en BIT(4)
> > +#define		DE_MUX_GLB_CTL_rtwb_port BIT(12)
> > +	u32 status;
> > +	u32 dbuff;
> > +	u32 size;
> > +};
> > +
> > +/* alpha blending */
> > +struct de_bld {
> > +	u32 fcolor_ctl;			/* 00 */
> > +	struct {
> > +		u32 fcolor;
> > +		u32 insize;
> > +		u32 offset;
> > +		u32 dum;
> > +	} attr[4];
> > +	u32 dum0[15];			/* (end of clear offset) */
> > +	u32 route;			/* 80 */
> > +	u32 premultiply;
> > +	u32 bkcolor;
> > +	u32 output_size;
> > +	u32 bld_mode[4];
> > +	u32 dum1[4];
> > +	u32 ck_ctl;			/* b0 */
> > +	u32 ck_cfg;
> > +	u32 dum2[2];
> > +	u32 ck_max[4];			/* c0 */
> > +	u32 dum3[4];
> > +	u32 ck_min[4];			/* e0 */
> > +	u32 dum4[3];
> > +	u32 out_ctl;			/* fc */
> > +};
> > +
> > +/* VI channel */
> > +struct de_vi {
> > +	struct {
> > +		u32 attr;
> > +#define			VI_CFG_ATTR_en BIT(0)
> > +#define			VI_CFG_ATTR_fcolor_en BIT(4)
> > +#define			VI_CFG_ATTR_fmt_SHIFT 8
> > +#define			VI_CFG_ATTR_fmt_MASK GENMASK(12, 8)
> > +#define			VI_CFG_ATTR_ui_sel BIT(15)
> > +#define			VI_CFG_ATTR_top_down BIT(23)
> > +		u32 size;
> > +		u32 coord;
> > +#define VI_N_PLANES 3
> > +		u32 pitch[VI_N_PLANES];
> > +		u32 top_laddr[VI_N_PLANES];
> > +		u32 bot_laddr[VI_N_PLANES];
> > +	} cfg[4];
> > +	u32 fcolor[4];			/* c0 */
> > +	u32 top_haddr[VI_N_PLANES];	/* d0 */
> > +	u32 bot_haddr[VI_N_PLANES];	/* dc */
> > +	u32 ovl_size[2];		/* e8 */
> > +	u32 hori[2];			/* f0 */
> > +	u32 vert[2];			/* f8 */
> > +};
> > +
> > +/* UI channel */
> > +struct de_ui {
> > +	struct {
> > +		u32 attr;
> > +#define			UI_CFG_ATTR_en BIT(0)
> > +#define			UI_CFG_ATTR_alpmod_SHIFT 1
> > +#define			UI_CFG_ATTR_alpmod_MASK GENMASK(2, 1)
> > +#define			UI_CFG_ATTR_fcolor_en BIT(4)
> > +#define			UI_CFG_ATTR_fmt_SHIFT 8
> > +#define			UI_CFG_ATTR_fmt_MASK GENMASK(12, 8)
> > +#define			UI_CFG_ATTR_top_down BIT(23)
> > +#define			UI_CFG_ATTR_alpha_SHIFT 24
> > +#define			UI_CFG_ATTR_alpha_MASK GENMASK(31, 24)
> > +		u32 size;
> > +		u32 coord;
> > +		u32 pitch;
> > +		u32 top_laddr;
> > +		u32 bot_laddr;
> > +		u32 fcolor;
> > +		u32 dum;
> > +	} cfg[4];			/* 00 */
> > +	u32 top_haddr;			/* 80 */
> > +	u32 bot_haddr;
> > +	u32 ovl_size;			/* 88 */
> > +};
> 
> Please use defines instead of the structures.

Juggling with data in arrays is painful when the offsets are defined by
defines, and structures are so much readable.

> > +
> > +/* coordinates and sizes */
> > +#define XY(x, y) (((y) << 16) | (x))
> > +#define WH(w, h) (((h - 1) << 16) | (w - 1))
> > +
> > +/* UI video formats */
> > +#define DE2_FORMAT_ARGB_8888 0
> > +#define DE2_FORMAT_BGRA_8888 3
> > +#define DE2_FORMAT_XRGB_8888 4
> > +#define DE2_FORMAT_RGB_888 8
> > +#define DE2_FORMAT_BGR_888 9
> > +
> > +/* VI video formats */
> > +#define DE2_FORMAT_YUV422_I_YVYU 1	/* Y-V-Y-U */
> > +#define DE2_FORMAT_YUV422_I_UYVY 2	/* U-Y-V-Y */
> > +#define DE2_FORMAT_YUV422_I_YUYV 3	/* Y-U-Y-V */
> > +#define DE2_FORMAT_YUV422_P 6		/* YYYY UU VV planar */
> > +#define DE2_FORMAT_YUV420_P 10		/* YYYY U V planar */
> > +
> > +#define glb_read(base, member) \
> > +	readl_relaxed(base + offsetof(struct de_glb, member))
> > +#define glb_write(base, member, data) \
> > +	writel_relaxed(data, base + offsetof(struct de_glb, member))
> > +#define bld_read(base, member) \
> > +	readl_relaxed(base + offsetof(struct de_bld, member))
> > +#define bld_write(base, member, data) \
> > +	writel_relaxed(data, base + offsetof(struct de_bld, member))
> > +#define ui_read(base, member) \
> > +	readl_relaxed(base + offsetof(struct de_ui, member))
> > +#define ui_write(base, member, data) \
> > +	writel_relaxed(data, base + offsetof(struct de_ui, member))
> > +#define vi_read(base, member) \
> > +	readl_relaxed(base + offsetof(struct de_vi, member))
> > +#define vi_write(base, member, data) \
> > +	writel_relaxed(data, base + offsetof(struct de_vi, member))
> > +
> > +static const struct {
> > +	char chan;
> > +	char layer;
> > +	char pipe;
> > +} plane2layer[DE2_N_PLANES] = {
> > +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> > +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> > +	[DE2_VI_PLANE] =	{0, 1, 0},
> > +};
> 
> Comments?

This
	primary plane is channel 0 (VI), layer 0, pipe 0
	cursor plane is channel 1 (UI), layer 0, pipe 1
	overlay plane is channel 0 (VI), layer 1, pipe 0
or the full explanation:
    Constraints:
	The VI channels can do RGB or YUV, while UI channels can do RGB
	only.
	The LCD 0 has 1 VI channel and 4 UI channels, while
	LCD 1 has only 1 VI channel and 1 UI channel.
	The cursor must go to a channel bigger than the primary channel,
	otherwise it is not transparent.
    First try:
	Letting the primary plane (usually RGB) in the 2nd channel (UI),
	as this is done in the legacy driver, asks for the cursor to go
	to the next channel (UI), but this one does not exist in LCD1.
    Retained layout:
	So, we must use only 2 channels for the same behaviour on LCD0
	(H3) and LCD1 (A83T)
	The retained combination is:
		- primary plane in the first channel (VI),
		- cursor plane inthe 2nd channel (UI), and
		- overlay plane in the 1st channel (VI).

	Note that there could be 3 overlay planes (a channel has 4
	layers), but I am not sure that the A83T or the H3 could
	support 3 simultaneous video streams...

> > +static inline void de_write(struct priv *priv, int reg, u32 data)
> > +{
> > +	writel_relaxed(data, priv->mmio + reg);
> > +}
> > +
> > +static inline u32 de_read(struct priv *priv, int reg)
> > +{
> > +	return readl_relaxed(priv->mmio + reg);
> > +}
> > +
> > +static void de_lcd_select(struct priv *priv,
> > +			int lcd_num,
> > +			void __iomem *mux_o)
> > +{
> > +	u32 data;
> > +
> > +	/* select the LCD */
> > +	data = de_read(priv, DE_SEL_REG);
> > +	data &= ~1;
> > +	de_write(priv, DE_SEL_REG, data);
> > +
> > +	/* double register switch */
> > +	glb_write(mux_o + DE_MUX_GLB_REGS, dbuff, 1);
> > +}
> > +
> > +void de2_de_plane_update(struct priv *priv,
> > +			int lcd_num, int plane_ix,
> > +			struct drm_plane_state *state,
> > +			struct drm_plane_state *old_state)
> > +{
> > +	struct drm_framebuffer *fb = state->fb;
> > +	struct drm_gem_cma_object *gem;
> > +	void __iomem *mux_o = priv->mmio;
> > +	void __iomem *chan_o;
> > +	u32 size = WH(state->crtc_w, state->crtc_h);
> > +	u32 coord;
> > +	u32 screen_size;
> > +	u32 data, fcolor;
> > +	u32 ui_sel, alpha_glob;
> > +	int chan, layer, x, y;
> > +	unsigned fmt;
> > +	unsigned long flags;
> > +
> > +	chan = plane2layer[plane_ix].chan;
> > +	layer = plane2layer[plane_ix].layer;
> > +
> > +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> > +	chan_o = mux_o;
> > +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> > +
> > +	x = state->crtc_x >= 0 ? state->crtc_x : 0;
> > +	y = state->crtc_y >= 0 ? state->crtc_y : 0;
> > +	coord = XY(x, y);
> > +
> > +	/* handle the cursor move */
> > +	if (plane_ix == DE2_CURSOR_PLANE
> > +	 && fb == old_state->fb) {
> > +		spin_lock_irqsave(&de_lock, flags);
> > +		de_lcd_select(priv, lcd_num, mux_o);
> > +		if (chan == 0)
> > +			vi_write(chan_o, cfg[layer].coord, coord);
> > +		else
> > +			ui_write(chan_o, cfg[layer].coord, coord);
> > +		spin_unlock_irqrestore(&de_lock, flags);
> > +		return;
> > +	}
> > +
> > +	gem = drm_fb_cma_get_gem_obj(fb, 0);
> > +
> > +	ui_sel = alpha_glob = 0;
> > +	switch (fb->pixel_format) {
> > +	case DRM_FORMAT_ARGB8888:
> > +		fmt = DE2_FORMAT_ARGB_8888;
> > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > +		break;
> > +	case DRM_FORMAT_BGRA8888:
> > +		fmt = DE2_FORMAT_BGRA_8888;
> > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > +		break;
> > +	case DRM_FORMAT_XRGB8888:
> > +		fmt = DE2_FORMAT_XRGB_8888;
> > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > +		alpha_glob = (1 << UI_CFG_ATTR_alpmod_SHIFT) |
> > +				(0xff << UI_CFG_ATTR_alpha_SHIFT);
> > +		break;
> > +	case DRM_FORMAT_RGB888:
> > +		fmt = DE2_FORMAT_RGB_888;
> > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > +		break;
> > +	case DRM_FORMAT_BGR888:
> > +		fmt = DE2_FORMAT_BGR_888;
> > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > +		break;
> > +	case DRM_FORMAT_YUYV:
> > +		fmt = DE2_FORMAT_YUV422_I_YUYV;
> > +		break;
> > +	case DRM_FORMAT_YVYU:
> > +		fmt = DE2_FORMAT_YUV422_I_YVYU;
> > +		break;
> > +	case DRM_FORMAT_YUV422:
> > +		fmt = DE2_FORMAT_YUV422_P;
> > +		break;
> > +	case DRM_FORMAT_YUV420:
> > +		fmt = DE2_FORMAT_YUV420_P;
> > +		break;
> > +	case DRM_FORMAT_UYVY:
> > +		fmt = DE2_FORMAT_YUV422_I_UYVY;
> > +		break;
> > +	default:
> > +		pr_err("format %.4s not yet treated\n",
> > +			(char *) &fb->pixel_format);
> > +		return;
> > +	}
> > +
> > +	spin_lock_irqsave(&de_lock, flags);
> > +
> > +	screen_size = plane_ix == DE2_PRIMARY_PLANE ?
> > +			size :
> > +			glb_read(mux_o + DE_MUX_GLB_REGS, size);
> > +
> > +	/* prepare the activation of alpha blending (1 bit per plane) */
> > +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl)
> > +			| (0x100 << plane2layer[plane_ix].pipe);
> > +
> > +	de_lcd_select(priv, lcd_num, mux_o);
> > +
> > +	if (chan == 0) {	/* VI channel */
> > +		int i;
> > +
> > +		data = VI_CFG_ATTR_en | (fmt << VI_CFG_ATTR_fmt_SHIFT) |
> > +					ui_sel;
> > +		vi_write(chan_o, cfg[layer].attr, data);
> > +		vi_write(chan_o, cfg[layer].size, size);
> > +		vi_write(chan_o, cfg[layer].coord, coord);
> > +		for (i = 0; i < VI_N_PLANES; i++) {
> > +			vi_write(chan_o, cfg[layer].pitch[i],
> > +					fb->pitches[i] ? fb->pitches[i] :
> > +							fb->pitches[0]);
> > +			vi_write(chan_o, cfg[layer].top_laddr[i],
> > +				gem->paddr + fb->offsets[i]);
> > +			vi_write(chan_o, fcolor[layer], 0xff000000);
> > +		}
> > +		if (layer == 0)
> > +			vi_write(chan_o, ovl_size[0], screen_size);
> > +
> > +	} else {		/* UI channel */
> > +		data = UI_CFG_ATTR_en | (fmt << UI_CFG_ATTR_fmt_SHIFT) |
> > +			alpha_glob;
> > +		ui_write(chan_o, cfg[layer].attr, data);
> > +		ui_write(chan_o, cfg[layer].size, size);
> > +		ui_write(chan_o, cfg[layer].coord, coord);
> > +		ui_write(chan_o, cfg[layer].pitch, fb->pitches[0]);
> > +		ui_write(chan_o, cfg[layer].top_laddr,
> > +				gem->paddr + fb->offsets[0]);
> > +		if (layer == 0)
> > +			ui_write(chan_o, ovl_size, screen_size);
> > +	}
> > +	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, fcolor);
> > +
> > +	spin_unlock_irqrestore(&de_lock, flags);
> > +}
> 
> Splitting that into functions would make it a bit more trivial and
> readable.

Not sure: there is a lot of common data and different I/O accesses.

> > +void de2_de_plane_disable(struct priv *priv,
> > +			int lcd_num, int plane_ix)
> > +{
> > +	void __iomem *mux_o = priv->mmio;
> > +	void __iomem *chan_o;
> > +	u32 fcolor;
> > +	int chan, layer, chan_disable = 0;
> > +	unsigned long flags;
> > +
> > +	chan = plane2layer[plane_ix].chan;
> > +	layer = plane2layer[plane_ix].layer;
> > +
> > +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> > +	chan_o = mux_o;
> > +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> > +
> > +	/* (only 2 layers) */
> > +	if (chan == 0) {
> > +		if (vi_read(chan_o, cfg[1 - layer].attr) == 0)
> > +			chan_disable = 1;
> > +	} else {
> > +		if (ui_read(chan_o, cfg[1 - layer].attr) == 0)
> > +			chan_disable = 1;
> > +	}
> > +
> > +	spin_lock_irqsave(&de_lock, flags);
> > +
> > +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl);
> > +
> > +	de_lcd_select(priv, lcd_num, mux_o);
> > +
> > +	if (chan == 0)
> > +		vi_write(chan_o, cfg[layer].attr, 0);
> > +	else
> > +		ui_write(chan_o, cfg[layer].attr, 0);
> > +
> > +	if (chan_disable)
> > +		bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl,
> > +			fcolor & ~(0x100 << plane2layer[plane_ix].pipe));
> > +
> > +	spin_unlock_irqrestore(&de_lock, flags);
> > +}
> 
> Can't you just disable it?

Which 'it'? A layer must be disabled and it is not useful to let the
DE2 processor to scan a pipe (channel) without any layer.

> > +void de2_de_panel_init(struct priv *priv, int lcd_num,
> > +			struct drm_display_mode *mode)
> > +{
> > +	void __iomem *mux_o = priv->mmio;
> > +	u32 size = WH(mode->hdisplay, mode->vdisplay);
> > +	unsigned i;
> > +	unsigned long flags;
> > +
> > +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> > +
> > +	DRM_DEBUG_DRIVER("%dx%d\n", mode->hdisplay, mode->vdisplay);
> > +
> > +	spin_lock_irqsave(&de_lock, flags);
> > +
> > +	de_lcd_select(priv, lcd_num, mux_o);
> > +
> > +	glb_write(mux_o + DE_MUX_GLB_REGS, size, size);
> > +
> > +	/* set alpha blending */
> > +	for (i = 0; i < 4; i++) {
> > +		bld_write(mux_o + DE_MUX_BLD_REGS, attr[i].fcolor, 0xff000000);
> > +		bld_write(mux_o + DE_MUX_BLD_REGS, attr[i].insize, size);
> > +	}
> > +	bld_write(mux_o + DE_MUX_BLD_REGS, output_size, size);
> > +	bld_write(mux_o + DE_MUX_BLD_REGS, out_ctl,
> > +			mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 0);
> > +
> > +	spin_unlock_irqrestore(&de_lock, flags);
> > +}
> > +
> > +void de2_de_enable(struct priv *priv, int lcd_num)
> > +{
	[snip]
> > +}
> > +
> > +void de2_de_disable(struct priv *priv, int lcd_num)
> > +{
> > +	u32 data;
> > +
> > +	data = ~(1 << lcd_num);
> > +	de_write(priv, DE_MOD_REG,
> > +			de_read(priv, DE_MOD_REG) & data);
> > +	de_write(priv, DE_GATE_REG,
> > +			de_read(priv, DE_GATE_REG) & data);
> > +	de_write(priv, DE_RESET_REG,
> > +			de_read(priv, DE_RESET_REG) & data);
> > +}
> > +
> > +int de2_de_init(struct priv *priv, struct device *dev)
> > +{
> > +	struct resource *res;
> > +	int ret;
> > +
> > +	DRM_DEBUG_DRIVER("\n");
> > +
> > +	res = platform_get_resource(to_platform_device(dev),
> > +				IORESOURCE_MEM, 0);
> > +	if (!res) {
> > +		dev_err(dev, "failed to get memory resource\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	priv->mmio = devm_ioremap_resource(dev, res);
> > +	if (IS_ERR(priv->mmio)) {
> > +		dev_err(dev, "failed to map registers\n");
> > +		return PTR_ERR(priv->mmio);
> > +	}
> > +
> > +	priv->gate = devm_clk_get(dev, "gate");	/* optional */
> 
> Error checking
> 
> > +
> > +	priv->clk = devm_clk_get(dev, "clock");
> > +	if (IS_ERR(priv->clk)) {
> > +		dev_err(dev, "video clock err %d\n", (int) PTR_ERR(priv->clk));
> > +		return PTR_ERR(priv->clk);
> > +	}
> > +
> > +	priv->rstc = devm_reset_control_get_optional(dev, NULL);
> > +
> > +	if (!IS_ERR(priv->rstc)) {
> > +		ret = reset_control_deassert(priv->rstc);
> > +		if (ret) {
> > +			dev_err(dev, "reset deassert err %d\n", ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	if (!IS_ERR(priv->gate)) {
> > +		ret = clk_prepare_enable(priv->gate);
> > +		if (ret)
> > +			goto err_gate;
> > +	}
> > +
> > +	ret = clk_prepare_enable(priv->clk);
> > +	if (ret)
> > +		goto err_enable;
> > +	if (priv->soc_type == SOC_A83T)
> > +		clk_set_rate(priv->clk, DE_CLK_RATE_A83T);
> > +	else
> > +		clk_set_rate(priv->clk, DE_CLK_RATE_H3);
> > +
> > +	/* set the A83T clock divider = 500 / 250 */
> > +	if (priv->soc_type == SOC_A83T)
> > +		de_write(priv, DE_DIV_REG,
> > +				0x00000011);	/* div = 2 for both LCDs */
> > +
> > +	return 0;
> > +
> > +err_enable:
> > +	clk_disable_unprepare(priv->gate);
> > +err_gate:
> > +	if (!IS_ERR(priv->rstc))
> > +		reset_control_assert(priv->rstc);
> > +	return ret;
> > +}
> > +
> > +void de2_de_cleanup(struct priv *priv)
> > +{
> > +	clk_disable_unprepare(priv->clk);
> > +	clk_disable_unprepare(priv->gate);
> > +	if (!IS_ERR(priv->rstc))
> > +		reset_control_assert(priv->rstc);
> > +}
	[snip]
> > diff --git a/drivers/gpu/drm/sunxi/de2_drv.c b/drivers/gpu/drm/sunxi/de2_drv.c
> > new file mode 100644
> > index 0000000..5daa15c
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sunxi/de2_drv.c
	[snip]
> > +
> > +#ifdef CONFIG_PM_SLEEP
> > +/*
> > + * Power management
> > + */
> > +static int de2_pm_suspend(struct device *dev)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(dev);
> > +
> > +	drm_kms_helper_poll_disable(drm);
> > +	return 0;
> > +}
> > +
> > +static int de2_pm_resume(struct device *dev)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(dev);
> > +
> > +	drm_kms_helper_poll_enable(drm);
> > +	return 0;
> > +}
> > +#endif
> > +
> > +static const struct dev_pm_ops de2_pm_ops = {
> > +	SET_SYSTEM_SLEEP_PM_OPS(de2_pm_suspend, de2_pm_resume)
> > +};
> 
> Why do you need that? How did you test it? There's no runtime_pm calls
> in your kernel.

That's not tested. I will remove this.

	[snip]
> > +static struct platform_driver de2_drm_platform_driver = {
> > +	.probe      = de2_drm_probe,
> > +	.remove     = de2_drm_remove,
> > +	.driver     = {
> > +		.name = DRIVER_NAME,
> > +		.pm = &de2_pm_ops,
> > +		.of_match_table = de2_drm_of_match,
> > +	},
> > +};
> > +
> > +static int __init de2_drm_init(void)
> > +{
> > +	int ret;
> > +
> > +/* uncomment to activate the drm traces at startup time */
> > +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> > +			DRM_UT_PRIME | DRM_UT_ATOMIC; */
> 
> That's useless.

Right, but it seems that some people don't know how to debug a DRM
driver. This is only a reminder.

> > +	DRM_DEBUG_DRIVER("\n");
> > +
> > +	ret = platform_driver_register(&de2_lcd_platform_driver);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = platform_driver_register(&de2_drm_platform_driver);
> > +	if (ret < 0)
> > +		platform_driver_unregister(&de2_lcd_platform_driver);
> > +
> > +	return ret;
> > +}
> 
> And that really shouldn't be done that way.

May you explain?

> > +static void __exit de2_drm_fini(void)
> > +{
> > +	platform_driver_unregister(&de2_lcd_platform_driver);
> > +	platform_driver_unregister(&de2_drm_platform_driver);
> > +}
> > +
> > +module_init(de2_drm_init);
> > +module_exit(de2_drm_fini);
> > +
> > +MODULE_AUTHOR("Jean-Francois Moine <moinejf@free.fr>");
> > +MODULE_DESCRIPTION("Allwinner DE2 DRM Driver");
> > +MODULE_LICENSE("GPL v2");
> > diff --git a/drivers/gpu/drm/sunxi/de2_plane.c b/drivers/gpu/drm/sunxi/de2_plane.c
> > new file mode 100644
> > index 0000000..b338684
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sunxi/de2_plane.c
> > @@ -0,0 +1,119 @@
> > +/*
> > + * Allwinner DRM driver - DE2 planes
> > + *
> > + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License as
> > + * published by the Free Software Foundation; either version 2 of
> > + * the License, or (at your option) any later version.
> > + */
> > +
> > +#include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_plane_helper.h>
> > +#include <drm/drm_crtc_helper.h>
> > +
> > +#include "de2_drm.h"
> > +#include "de2_crtc.h"
> > +
> > +/* plane formats */
> > +static const uint32_t ui_formats[] = {
> > +	DRM_FORMAT_ARGB8888,
> > +	DRM_FORMAT_BGRA8888,
> > +	DRM_FORMAT_XRGB8888,
> > +	DRM_FORMAT_RGB888,
> > +	DRM_FORMAT_BGR888,
> > +};
> > +
> > +static const uint32_t vi_formats[] = {
> > +	DRM_FORMAT_XRGB8888,
> > +	DRM_FORMAT_YUYV,
> > +	DRM_FORMAT_YVYU,
> > +	DRM_FORMAT_YUV422,
> > +	DRM_FORMAT_YUV420,
> > +	DRM_FORMAT_UYVY,
> > +	DRM_FORMAT_BGRA8888,
> > +	DRM_FORMAT_RGB888,
> > +	DRM_FORMAT_BGR888,
> > +};
	[snip]
> > +static int de2_one_plane_init(struct drm_device *drm,
> > +				struct drm_plane *plane,
> > +				int type, int possible_crtcs,
> > +				const uint32_t *formats,
> > +				int nformats)
> > +{
> > +	int ret;
> > +
> > +	ret = drm_universal_plane_init(drm, plane, possible_crtcs,
> > +				&plane_funcs,
> > +				formats, nformats, type, NULL);
> > +	if (ret >= 0)
> > +		drm_plane_helper_add(plane, &plane_helper_funcs);
> > +
> > +	return ret;
> > +}
> > +
> > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> > +{
> > +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> > +
> > +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> > +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> > +				ui_formats, ARRAY_SIZE(ui_formats));
> > +	if (ret >= 0)
> > +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> > +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> > +				ui_formats, ARRAY_SIZE(ui_formats));
> 
> Nothing looks really special about that cursor plane. Any reasion not
> to make it an overlay?

As explained above (channel/layer/pipe plane definitions), the cursor
cannot go in a channel lower or equal to the one of the primary plane.
Then, it must be known and, so, have an explicit plane.
Jean-Francois Moine Oct. 25, 2016, 2:16 p.m. UTC | #5
On Tue, 25 Oct 2016 08:44:22 +0200
Daniel Vetter <daniel@ffwll.ch> wrote:

> > +	/* start the subdevices */
> > +	ret = component_bind_all(dev, drm);
> > +	if (ret < 0)
> > +		goto out2;
> > +
> > +	ret = drm_dev_register(drm, 0);
> 
> This needs to be the very last step in your driver load sequence.
> Kerneldoc explains why. Similar, but inverted for unloading:
> drm_dev_unregister is the very first thing you must call.

Thanks, and also for embedding the drm device.
Andre Przywara Oct. 25, 2016, 11:52 p.m. UTC | #6
On 25/10/16 15:14, Jean-Francois Moine wrote:
> On Mon, 24 Oct 2016 16:04:19 +0200
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
>> Hi,
> 
> Hi Maxime,
> 
>> On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
>>> Allwinner's recent SoCs, as A64, A83T and H3, contain a new display
>>> engine, DE2.
>>> This patch adds a DRM video driver for this device.
>>>
>>> Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
>>
>> Output from checkpatch:
>> total: 0 errors, 20 warnings, 83 checks, 1799 lines checked
>>
>>> ---
>>>  .../bindings/display/sunxi/sunxi-de2.txt           |  83 +++
>>>  drivers/gpu/drm/Kconfig                            |   2 +
>>>  drivers/gpu/drm/Makefile                           |   1 +
>>>  drivers/gpu/drm/sunxi/Kconfig                      |  21 +
>>>  drivers/gpu/drm/sunxi/Makefile                     |   7 +
>>>  drivers/gpu/drm/sunxi/de2_crtc.c                   | 475 +++++++++++++++++
>>>  drivers/gpu/drm/sunxi/de2_crtc.h                   |  63 +++
>>>  drivers/gpu/drm/sunxi/de2_de.c                     | 591 +++++++++++++++++++++
>>>  drivers/gpu/drm/sunxi/de2_drm.h                    |  47 ++
>>>  drivers/gpu/drm/sunxi/de2_drv.c                    | 378 +++++++++++++
>>>  drivers/gpu/drm/sunxi/de2_plane.c                  | 119 +++++
>>>  11 files changed, 1787 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
>>>  create mode 100644 drivers/gpu/drm/sunxi/Kconfig
>>>  create mode 100644 drivers/gpu/drm/sunxi/Makefile
>>>  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.c
>>>  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.h
>>>  create mode 100644 drivers/gpu/drm/sunxi/de2_de.c
>>>  create mode 100644 drivers/gpu/drm/sunxi/de2_drm.h
>>>  create mode 100644 drivers/gpu/drm/sunxi/de2_drv.c
>>>  create mode 100644 drivers/gpu/drm/sunxi/de2_plane.c
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
>>> new file mode 100644
>>> index 0000000..f9cd67a
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
>>> @@ -0,0 +1,83 @@
>>> +Allwinner sunxi Display Engine 2 subsystem
>>> +==========================================
>>> +
>>> +The sunxi DE2 subsystem contains a display controller (DE2),
>>
>> sunxi is a made up name, and doesn't really mean anything. You can
>> call it either sun8i (because it was introduced in that family).
> 
> OK.
> 
>>> +one or two LCD controllers (TCON) and their external interfaces.
>>> +
>>> +Display controller
>>> +==================
>>> +
>>> +Required properties:
>>> +
>>> +- compatible: value should be one of the following
>>> +		"allwinner,sun8i-a83t-display-engine"
>>> +		"allwinner,sun8i-h3-display-engine"
>>> +
>>> +- clocks: must include clock specifiers corresponding to entries in the
>>> +		clock-names property.
>>> +
>>> +- clock-names: must contain
>>> +		"gate": for DE activation
>>> +		"clock": DE clock
>>
>> We've been calling them bus and mod.
> 
> I can understand "bus" (which is better than "apb"), but why "mod"?
> 
>>> +
>>> +- resets: phandle to the reset of the device
>>> +
>>> +- ports: phandle's to the LCD ports
>>
>> Please use the OF graph.
> 
> These ports are references to the graph of nodes. See
> 	http://www.kernelhub.org/?msg=911825&p=2
> 
> 	[snip]
>>> diff --git a/drivers/gpu/drm/sunxi/de2_crtc.c b/drivers/gpu/drm/sunxi/de2_crtc.c
>>> new file mode 100644
>>> index 0000000..dae0fab
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/sunxi/de2_crtc.c
>>> @@ -0,0 +1,475 @@
>>> +/*
>>> + * Allwinner DRM driver - DE2 CRTC
>>> + *
>>> + * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
>>> + *
>>> + * This program is free software; you can redistribute it and/or
>>> + * modify it under the terms of the GNU General Public License as
>>> + * published by the Free Software Foundation; either version 2 of
>>> + * the License, or (at your option) any later version.
>>> + */
>>> +
>>> +#include <linux/component.h>
>>> +#include <drm/drm_crtc_helper.h>
>>> +#include <drm/drm_atomic_helper.h>
>>> +#include <asm/io.h>
>>> +#include <linux/of_irq.h>
>>> +
>>> +#include "de2_drm.h"
>>> +#include "de2_crtc.h"
>>> +
>>> +/* I/O map */
>>> +
>>> +struct tcon {
>>> +	u32 gctl;
>>> +#define		TCON_GCTL_TCON_En BIT(31)
>>> +	u32 gint0;
>>> +#define		TCON_GINT0_TCON1_Vb_Int_En BIT(30)
>>> +#define		TCON_GINT0_TCON1_Vb_Int_Flag BIT(14)
>>> +	u32 gint1;
>>> +	u32 dum0[13];
>>> +	u32 tcon0_ctl;				/* 0x40 */
>>> +#define		TCON0_CTL_TCON_En BIT(31)
>>> +	u32 dum1[19];
>>> +	u32 tcon1_ctl;				/* 0x90 */
>>> +#define		TCON1_CTL_TCON_En BIT(31)
>>> +#define		TCON1_CTL_Interlace_En BIT(20)
>>> +#define		TCON1_CTL_Start_Delay_SHIFT 4
>>> +#define		TCON1_CTL_Start_Delay_MASK GENMASK(8, 4)
>>> +	u32 basic0;			/* XI/YI */
>>> +	u32 basic1;			/* LS_XO/LS_YO */
>>> +	u32 basic2;			/* XO/YO */
>>> +	u32 basic3;			/* HT/HBP */
>>> +	u32 basic4;			/* VT/VBP */
>>> +	u32 basic5;			/* HSPW/VSPW */
>>> +	u32 dum2;
>>> +	u32 ps_sync;				/* 0xb0 */
>>> +	u32 dum3[15];
>>> +	u32 io_pol;				/* 0xf0 */
>>> +#define		TCON1_IO_POL_IO0_inv BIT(24)
>>> +#define		TCON1_IO_POL_IO1_inv BIT(25)
>>> +#define		TCON1_IO_POL_IO2_inv BIT(26)
>>> +	u32 io_tri;
>>> +	u32 dum4[2];
>>> +
>>> +	u32 ceu_ctl;				/* 0x100 */
>>> +#define     TCON_CEU_CTL_ceu_en BIT(31)
>>> +	u32 dum5[3];
>>> +	u32 ceu_rr;
>>> +	u32 ceu_rg;
>>> +	u32 ceu_rb;
>>> +	u32 ceu_rc;
>>> +	u32 ceu_gr;
>>> +	u32 ceu_gg;
>>> +	u32 ceu_gb;
>>> +	u32 ceu_gc;
>>> +	u32 ceu_br;
>>> +	u32 ceu_bg;
>>> +	u32 ceu_bb;
>>> +	u32 ceu_bc;
>>> +	u32 ceu_rv;
>>> +	u32 ceu_gv;
>>> +	u32 ceu_bv;
>>> +	u32 dum6[45];
>>> +
>>> +	u32 mux_ctl;				/* 0x200 */
>>> +	u32 dum7[63];
>>> +
>>> +	u32 fill_ctl;				/* 0x300 */
>>> +	u32 fill_start0;
>>> +	u32 fill_end0;
>>> +	u32 fill_data0;
>>> +};
>>
>> Please use defines instead of the structures.
> 
> I think that structures are more readable.

I think for the kernel we don't use C structs to model register frames.
The main argument against it is that putting them into a structure puts
the actual offset into the hands of the compiler, which is free to
insert padding and alignment - within the rules of the ABI. This happens
to work when we use 32-bit registers and maybe char fillers only. Most
ABIs seem to agree on this part, but there is no guarantee.
In fact all those various ABIs used by the kernel could have subtle
differences between architectures (for instance for alignment of 64-bit
members), so we produce potentially non-portable code.

Also I find it actually harder to read, since the manual refers to
register offset addresses, which makes it hard to match with the code,
especially if we deviate with the register naming. The fact that we have
occasional *comments* to denote the actual offset is a hint that
something is sub-optimal.
Also having these dummy fillers is really error prone once we insert new
registers, as the fill value has to be adjusted accordingly.

So can we stick with what the kernel uses elsewhere and don't pretend
that because the current GCC compiles that fine on ARM it will be good
forever?

Thanks!
Andre.
Maxime Ripard Oct. 27, 2016, 10:03 p.m. UTC | #7
On Tue, Oct 25, 2016 at 04:14:41PM +0200, Jean-Francois Moine wrote:
> > > +Display controller
> > > +==================
> > > +
> > > +Required properties:
> > > +
> > > +- compatible: value should be one of the following
> > > +		"allwinner,sun8i-a83t-display-engine"
> > > +		"allwinner,sun8i-h3-display-engine"
> > > +
> > > +- clocks: must include clock specifiers corresponding to entries in the
> > > +		clock-names property.
> > > +
> > > +- clock-names: must contain
> > > +		"gate": for DE activation
> > > +		"clock": DE clock
> > 
> > We've been calling them bus and mod.
> 
> I can understand "bus" (which is better than "apb"), but why "mod"?

Allwinner has been calling the clocks that are supposed to generate
the external signals (depending on where you were looking) module or
mod clocks (which is also why we have mod in the clock
compatibles). The module 1 clocks being used for the audio and the
module 0 for the rest (SPI, MMC, NAND, display, etc.)

> > > +
> > > +- resets: phandle to the reset of the device
> > > +
> > > +- ports: phandle's to the LCD ports
> > 
> > Please use the OF graph.
> 
> These ports are references to the graph of nodes. See
> 	http://www.kernelhub.org/?msg=911825&p=2

In an OF-graph, your phandle to the LCD controller would be replaced
by an output endpoint.

> 
> 	[snip]
> > > +struct tcon {
> > > +	u32 gctl;
> > > +#define		TCON_GCTL_TCON_En BIT(31)
> > > +	u32 gint0;
> > > +#define		TCON_GINT0_TCON1_Vb_Int_En BIT(30)
> > > +#define		TCON_GINT0_TCON1_Vb_Int_Flag BIT(14)
> > > +	u32 gint1;
> > > +	u32 dum0[13];
> > > +	u32 tcon0_ctl;				/* 0x40 */
> > > +#define		TCON0_CTL_TCON_En BIT(31)
> > > +	u32 dum1[19];
> > > +	u32 tcon1_ctl;				/* 0x90 */
> > > +#define		TCON1_CTL_TCON_En BIT(31)
> > > +#define		TCON1_CTL_Interlace_En BIT(20)
> > > +#define		TCON1_CTL_Start_Delay_SHIFT 4
> > > +#define		TCON1_CTL_Start_Delay_MASK GENMASK(8, 4)
> > > +	u32 basic0;			/* XI/YI */
> > > +	u32 basic1;			/* LS_XO/LS_YO */
> > > +	u32 basic2;			/* XO/YO */
> > > +	u32 basic3;			/* HT/HBP */
> > > +	u32 basic4;			/* VT/VBP */
> > > +	u32 basic5;			/* HSPW/VSPW */
> > > +	u32 dum2;
> > > +	u32 ps_sync;				/* 0xb0 */
> > > +	u32 dum3[15];
> > > +	u32 io_pol;				/* 0xf0 */
> > > +#define		TCON1_IO_POL_IO0_inv BIT(24)
> > > +#define		TCON1_IO_POL_IO1_inv BIT(25)
> > > +#define		TCON1_IO_POL_IO2_inv BIT(26)
> > > +	u32 io_tri;
> > > +	u32 dum4[2];
> > > +
> > > +	u32 ceu_ctl;				/* 0x100 */
> > > +#define     TCON_CEU_CTL_ceu_en BIT(31)
> > > +	u32 dum5[3];
> > > +	u32 ceu_rr;
> > > +	u32 ceu_rg;
> > > +	u32 ceu_rb;
> > > +	u32 ceu_rc;
> > > +	u32 ceu_gr;
> > > +	u32 ceu_gg;
> > > +	u32 ceu_gb;
> > > +	u32 ceu_gc;
> > > +	u32 ceu_br;
> > > +	u32 ceu_bg;
> > > +	u32 ceu_bb;
> > > +	u32 ceu_bc;
> > > +	u32 ceu_rv;
> > > +	u32 ceu_gv;
> > > +	u32 ceu_bv;
> > > +	u32 dum6[45];
> > > +
> > > +	u32 mux_ctl;				/* 0x200 */
> > > +	u32 dum7[63];
> > > +
> > > +	u32 fill_ctl;				/* 0x300 */
> > > +	u32 fill_start0;
> > > +	u32 fill_end0;
> > > +	u32 fill_data0;
> > > +};
> > 
> > Please use defines instead of the structures.
> 
> I think that structures are more readable.

That's not really the point. No one in the kernel uses it (and even
you use defines for registers offset in some places of that
patch). And then you have André arguments.

> > > +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> > > +{
> > > +	struct priv *priv = drm->dev_private;
> > > +	struct lcd *lcd = priv->lcds[crtc];
> > > +
> > > +	tcon_write(lcd->mmio, gint0,
> > > +			 tcon_read(lcd->mmio, gint0) &
> > > +					~TCON_GINT0_TCON1_Vb_Int_En);
> > > +}
> > > +
> > > +/* panel functions */
> > 
> > Panel functions? In the CRTC driver?
> 
> Yes, dumb panel.

What do you mean by that? Using a Parallel/RGB interface?

> 
> > > +static void de2_set_frame_timings(struct lcd *lcd)
> > > +{
> > > +	struct drm_crtc *crtc = &lcd->crtc;
> > > +	const struct drm_display_mode *mode = &crtc->mode;
> > > +	int interlace = mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 1;
> > > +	int start_delay;
> > > +	u32 data;
> > > +
> > > +	data = XY(mode->hdisplay - 1, mode->vdisplay / interlace - 1);
> > > +	tcon_write(lcd->mmio, basic0, data);
> > > +	tcon_write(lcd->mmio, basic1, data);
> > > +	tcon_write(lcd->mmio, basic2, data);
> > > +	tcon_write(lcd->mmio, basic3,
> > > +			XY(mode->htotal - 1,
> > > +				mode->htotal - mode->hsync_start - 1));
> > > +	tcon_write(lcd->mmio, basic4,
> > > +			XY(mode->vtotal * (3 - interlace),
> > > +				mode->vtotal - mode->vsync_start - 1));
> > > +	tcon_write(lcd->mmio, basic5,
> > > +			 XY(mode->hsync_end - mode->hsync_start - 1,
> > > +				mode->vsync_end - mode->vsync_start - 1));
> > > +
> > > +	tcon_write(lcd->mmio, ps_sync, XY(1, 1));
> > > +
> > > +	data = TCON1_IO_POL_IO2_inv;
> > > +	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
> > > +		data |= TCON1_IO_POL_IO0_inv;
> > > +	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
> > > +		data |= TCON1_IO_POL_IO1_inv;
> > > +	tcon_write(lcd->mmio, io_pol, data);
> > > +
> > > +	tcon_write(lcd->mmio, ceu_ctl,
> > > +		tcon_read(lcd->mmio, ceu_ctl) & ~TCON_CEU_CTL_ceu_en);
> > > +
> > > +	data = tcon_read(lcd->mmio, tcon1_ctl);
> > > +	if (interlace == 2)
> > > +		data |= TCON1_CTL_Interlace_En;
> > > +	else
> > > +		data &= ~TCON1_CTL_Interlace_En;
> > > +	tcon_write(lcd->mmio, tcon1_ctl, data);
> > > +
> > > +	tcon_write(lcd->mmio, fill_ctl, 0);
> > > +	tcon_write(lcd->mmio, fill_start0, mode->vtotal + 1);
> > > +	tcon_write(lcd->mmio, fill_end0, mode->vtotal);
> > > +	tcon_write(lcd->mmio, fill_data0, 0);
> > > +
> > > +	start_delay = (mode->vtotal - mode->vdisplay) / interlace - 5;
> > > +	if (start_delay > 31)
> > > +		start_delay = 31;
> > > +	data = tcon_read(lcd->mmio, tcon1_ctl);
> > > +	data &= ~TCON1_CTL_Start_Delay_MASK;
> > > +	data |= start_delay << TCON1_CTL_Start_Delay_SHIFT;
> > > +	tcon_write(lcd->mmio, tcon1_ctl, data);
> > > +
> > > +	tcon_write(lcd->mmio, io_tri, 0x0fffffff);
> > > +}
> > 
> > Some comments here would be nice, there's a lot of non trivial things.
> 
> ... and no documentation. I just set the values I saw in the I/O memory
> when running the legacy driver.

That's bad (but definitely not your fault) :/

> > > +	lcd->gate = devm_clk_get(dev, "gate");		/* optional */
> > 
> > Having some kind of error checking would still be nice.
> 
> And cancel the device creation?

Well, yes. If it cannot enable it, it will at best not work properly,
at worst be reset, so it won't be very useful anyway.

> > > +	if (!IS_ERR(lcd->rstc)) {
> > > +		ret = reset_control_deassert(lcd->rstc);
> > > +		if (ret) {
> > > +			dev_err(dev, "reset deassert err %d\n", ret);
> > > +			goto err;
> > > +		}
> > > +	}
> > > +
> > > +	if (!IS_ERR(lcd->gate)) {
> > > +		ret = clk_prepare_enable(lcd->gate);
> > > +		if (ret)
> > > +			goto err2;
> > > +	}
> > > +
> > > +	ret = clk_prepare_enable(lcd->clk);
> > > +	if (ret)
> > > +		goto err2;
> > 
> > Is there any reason not to do that in the enable / disable? Leaving
> > clocks running while the device has no guarantee that it's going to be
> > used seems like a waste of resources.
> 
> If the machine does not need video (network server, router..), it is simpler
> to prevent the video driver to be loaded (DT, module black list...).

You might not have control on any of it, or you might just have no
monitor attached for example. Recompiling the kernel or updating the
DT when you want to plug an HDMI monitor seems like a poor UX :)

> > > +static const struct {
> > > +	char chan;
> > > +	char layer;
> > > +	char pipe;
> > > +} plane2layer[DE2_N_PLANES] = {
> > > +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> > > +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> > > +	[DE2_VI_PLANE] =	{0, 1, 0},
> > > +};
> > 
> > Comments?
> 
> This
> 	primary plane is channel 0 (VI), layer 0, pipe 0
> 	cursor plane is channel 1 (UI), layer 0, pipe 1
> 	overlay plane is channel 0 (VI), layer 1, pipe 0
> or the full explanation:
>     Constraints:
> 	The VI channels can do RGB or YUV, while UI channels can do RGB
> 	only.
> 	The LCD 0 has 1 VI channel and 4 UI channels, while
> 	LCD 1 has only 1 VI channel and 1 UI channel.
> 	The cursor must go to a channel bigger than the primary channel,
> 	otherwise it is not transparent.
>     First try:
> 	Letting the primary plane (usually RGB) in the 2nd channel (UI),
> 	as this is done in the legacy driver, asks for the cursor to go
> 	to the next channel (UI), but this one does not exist in LCD1.
>     Retained layout:
> 	So, we must use only 2 channels for the same behaviour on LCD0
> 	(H3) and LCD1 (A83T)
> 	The retained combination is:
> 		- primary plane in the first channel (VI),
> 		- cursor plane inthe 2nd channel (UI), and
> 		- overlay plane in the 1st channel (VI).
> 
> 	Note that there could be 3 overlay planes (a channel has 4
> 	layers), but I am not sure that the A83T or the H3 could
> 	support 3 simultaneous video streams...

Do you know if the pipe works in the old display engine?

Especially about the two-steps composition that wouldn't allow you to
have alpha on all the planes?

If it is similar, I think hardcoding the pipe number is pretty bad,
because that would restrict the combination of planes and formats,
while some other might have worked.

> > > +static inline void de_write(struct priv *priv, int reg, u32 data)
> > > +{
> > > +	writel_relaxed(data, priv->mmio + reg);
> > > +}
> > > +
> > > +static inline u32 de_read(struct priv *priv, int reg)
> > > +{
> > > +	return readl_relaxed(priv->mmio + reg);
> > > +}
> > > +
> > > +static void de_lcd_select(struct priv *priv,
> > > +			int lcd_num,
> > > +			void __iomem *mux_o)
> > > +{
> > > +	u32 data;
> > > +
> > > +	/* select the LCD */
> > > +	data = de_read(priv, DE_SEL_REG);
> > > +	data &= ~1;
> > > +	de_write(priv, DE_SEL_REG, data);
> > > +
> > > +	/* double register switch */
> > > +	glb_write(mux_o + DE_MUX_GLB_REGS, dbuff, 1);
> > > +}
> > > +
> > > +void de2_de_plane_update(struct priv *priv,
> > > +			int lcd_num, int plane_ix,
> > > +			struct drm_plane_state *state,
> > > +			struct drm_plane_state *old_state)
> > > +{
> > > +	struct drm_framebuffer *fb = state->fb;
> > > +	struct drm_gem_cma_object *gem;
> > > +	void __iomem *mux_o = priv->mmio;
> > > +	void __iomem *chan_o;
> > > +	u32 size = WH(state->crtc_w, state->crtc_h);
> > > +	u32 coord;
> > > +	u32 screen_size;
> > > +	u32 data, fcolor;
> > > +	u32 ui_sel, alpha_glob;
> > > +	int chan, layer, x, y;
> > > +	unsigned fmt;
> > > +	unsigned long flags;
> > > +
> > > +	chan = plane2layer[plane_ix].chan;
> > > +	layer = plane2layer[plane_ix].layer;
> > > +
> > > +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> > > +	chan_o = mux_o;
> > > +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> > > +
> > > +	x = state->crtc_x >= 0 ? state->crtc_x : 0;
> > > +	y = state->crtc_y >= 0 ? state->crtc_y : 0;
> > > +	coord = XY(x, y);
> > > +
> > > +	/* handle the cursor move */
> > > +	if (plane_ix == DE2_CURSOR_PLANE
> > > +	 && fb == old_state->fb) {
> > > +		spin_lock_irqsave(&de_lock, flags);
> > > +		de_lcd_select(priv, lcd_num, mux_o);
> > > +		if (chan == 0)
> > > +			vi_write(chan_o, cfg[layer].coord, coord);
> > > +		else
> > > +			ui_write(chan_o, cfg[layer].coord, coord);
> > > +		spin_unlock_irqrestore(&de_lock, flags);
> > > +		return;
> > > +	}
> > > +
> > > +	gem = drm_fb_cma_get_gem_obj(fb, 0);
> > > +
> > > +	ui_sel = alpha_glob = 0;
> > > +	switch (fb->pixel_format) {
> > > +	case DRM_FORMAT_ARGB8888:
> > > +		fmt = DE2_FORMAT_ARGB_8888;
> > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > +		break;
> > > +	case DRM_FORMAT_BGRA8888:
> > > +		fmt = DE2_FORMAT_BGRA_8888;
> > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > +		break;
> > > +	case DRM_FORMAT_XRGB8888:
> > > +		fmt = DE2_FORMAT_XRGB_8888;
> > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > +		alpha_glob = (1 << UI_CFG_ATTR_alpmod_SHIFT) |
> > > +				(0xff << UI_CFG_ATTR_alpha_SHIFT);
> > > +		break;
> > > +	case DRM_FORMAT_RGB888:
> > > +		fmt = DE2_FORMAT_RGB_888;
> > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > +		break;
> > > +	case DRM_FORMAT_BGR888:
> > > +		fmt = DE2_FORMAT_BGR_888;
> > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > +		break;
> > > +	case DRM_FORMAT_YUYV:
> > > +		fmt = DE2_FORMAT_YUV422_I_YUYV;
> > > +		break;
> > > +	case DRM_FORMAT_YVYU:
> > > +		fmt = DE2_FORMAT_YUV422_I_YVYU;
> > > +		break;
> > > +	case DRM_FORMAT_YUV422:
> > > +		fmt = DE2_FORMAT_YUV422_P;
> > > +		break;
> > > +	case DRM_FORMAT_YUV420:
> > > +		fmt = DE2_FORMAT_YUV420_P;
> > > +		break;
> > > +	case DRM_FORMAT_UYVY:
> > > +		fmt = DE2_FORMAT_YUV422_I_UYVY;
> > > +		break;
> > > +	default:
> > > +		pr_err("format %.4s not yet treated\n",
> > > +			(char *) &fb->pixel_format);
> > > +		return;
> > > +	}
> > > +
> > > +	spin_lock_irqsave(&de_lock, flags);
> > > +
> > > +	screen_size = plane_ix == DE2_PRIMARY_PLANE ?
> > > +			size :
> > > +			glb_read(mux_o + DE_MUX_GLB_REGS, size);
> > > +
> > > +	/* prepare the activation of alpha blending (1 bit per plane) */
> > > +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl)
> > > +			| (0x100 << plane2layer[plane_ix].pipe);
> > > +
> > > +	de_lcd_select(priv, lcd_num, mux_o);
> > > +
> > > +	if (chan == 0) {	/* VI channel */
> > > +		int i;
> > > +
> > > +		data = VI_CFG_ATTR_en | (fmt << VI_CFG_ATTR_fmt_SHIFT) |
> > > +					ui_sel;
> > > +		vi_write(chan_o, cfg[layer].attr, data);
> > > +		vi_write(chan_o, cfg[layer].size, size);
> > > +		vi_write(chan_o, cfg[layer].coord, coord);
> > > +		for (i = 0; i < VI_N_PLANES; i++) {
> > > +			vi_write(chan_o, cfg[layer].pitch[i],
> > > +					fb->pitches[i] ? fb->pitches[i] :
> > > +							fb->pitches[0]);
> > > +			vi_write(chan_o, cfg[layer].top_laddr[i],
> > > +				gem->paddr + fb->offsets[i]);
> > > +			vi_write(chan_o, fcolor[layer], 0xff000000);
> > > +		}
> > > +		if (layer == 0)
> > > +			vi_write(chan_o, ovl_size[0], screen_size);
> > > +
> > > +	} else {		/* UI channel */
> > > +		data = UI_CFG_ATTR_en | (fmt << UI_CFG_ATTR_fmt_SHIFT) |
> > > +			alpha_glob;
> > > +		ui_write(chan_o, cfg[layer].attr, data);
> > > +		ui_write(chan_o, cfg[layer].size, size);
> > > +		ui_write(chan_o, cfg[layer].coord, coord);
> > > +		ui_write(chan_o, cfg[layer].pitch, fb->pitches[0]);
> > > +		ui_write(chan_o, cfg[layer].top_laddr,
> > > +				gem->paddr + fb->offsets[0]);
> > > +		if (layer == 0)
> > > +			ui_write(chan_o, ovl_size, screen_size);
> > > +	}
> > > +	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, fcolor);
> > > +
> > > +	spin_unlock_irqrestore(&de_lock, flags);
> > > +}
> > 
> > Splitting that into functions would make it a bit more trivial and
> > readable.
> 
> Not sure: there is a lot of common data and different I/O accesses.

You could still have different ones to set the buffers, formats and
coordinates for example.

> > > +void de2_de_plane_disable(struct priv *priv,
> > > +			int lcd_num, int plane_ix)
> > > +{
> > > +	void __iomem *mux_o = priv->mmio;
> > > +	void __iomem *chan_o;
> > > +	u32 fcolor;
> > > +	int chan, layer, chan_disable = 0;
> > > +	unsigned long flags;
> > > +
> > > +	chan = plane2layer[plane_ix].chan;
> > > +	layer = plane2layer[plane_ix].layer;
> > > +
> > > +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> > > +	chan_o = mux_o;
> > > +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> > > +
> > > +	/* (only 2 layers) */
> > > +	if (chan == 0) {
> > > +		if (vi_read(chan_o, cfg[1 - layer].attr) == 0)
> > > +			chan_disable = 1;
> > > +	} else {
> > > +		if (ui_read(chan_o, cfg[1 - layer].attr) == 0)
> > > +			chan_disable = 1;
> > > +	}
> > > +
> > > +	spin_lock_irqsave(&de_lock, flags);
> > > +
> > > +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl);
> > > +
> > > +	de_lcd_select(priv, lcd_num, mux_o);
> > > +
> > > +	if (chan == 0)
> > > +		vi_write(chan_o, cfg[layer].attr, 0);
> > > +	else
> > > +		ui_write(chan_o, cfg[layer].attr, 0);
> > > +
> > > +	if (chan_disable)
> > > +		bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl,
> > > +			fcolor & ~(0x100 << plane2layer[plane_ix].pipe));
> > > +
> > > +	spin_unlock_irqrestore(&de_lock, flags);
> > > +}
> > 
> > Can't you just disable it?
> 
> Which 'it'? A layer must be disabled and it is not useful to let the
> DE2 processor to scan a pipe (channel) without any layer.

Oh, so that's what it does.

I really think that you should put as much comments as possible on
what you found out working on this, especially because of the lack of
documentation.

> > > +static int __init de2_drm_init(void)
> > > +{
> > > +	int ret;
> > > +
> > > +/* uncomment to activate the drm traces at startup time */
> > > +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> > > +			DRM_UT_PRIME | DRM_UT_ATOMIC; */
> > 
> > That's useless.
> 
> Right, but it seems that some people don't know how to debug a DRM
> driver. This is only a reminder.
> 
> > > +	DRM_DEBUG_DRIVER("\n");
> > > +
> > > +	ret = platform_driver_register(&de2_lcd_platform_driver);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = platform_driver_register(&de2_drm_platform_driver);
> > > +	if (ret < 0)
> > > +		platform_driver_unregister(&de2_lcd_platform_driver);
> > > +
> > > +	return ret;
> > > +}
> > 
> > And that really shouldn't be done that way.
> 
> May you explain?

This goes against the whole idea of the device and driver
model. Drivers should only register themselves, device should be
created by buses (or by using some external components if the bus
can't: DT, ACPI, etc.). If there's a match, you get probed.

A driver that creates its own device just to probe itself violates
that.

> > > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> > > +{
> > > +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> > > +
> > > +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> > > +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > +	if (ret >= 0)
> > > +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> > > +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > 
> > Nothing looks really special about that cursor plane. Any reasion not
> > to make it an overlay?
> 
> As explained above (channel/layer/pipe plane definitions), the cursor
> cannot go in a channel lower or equal to the one of the primary plane.
> Then, it must be known and, so, have an explicit plane.

If you were to make it a plane, you could use atomic_check to check
this and make sure this doesn't happen. And you would gain a generic
plane that can be used for other purposes if needed.

Maxime
Jean-Francois Moine Oct. 28, 2016, 5:34 p.m. UTC | #8
On Fri, 28 Oct 2016 00:03:16 +0200
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> On Tue, Oct 25, 2016 at 04:14:41PM +0200, Jean-Francois Moine wrote:
> > > > +Display controller
> > > > +==================
> > > > +
> > > > +Required properties:
> > > > +
> > > > +- compatible: value should be one of the following
> > > > +		"allwinner,sun8i-a83t-display-engine"
> > > > +		"allwinner,sun8i-h3-display-engine"
> > > > +
> > > > +- clocks: must include clock specifiers corresponding to entries in the
> > > > +		clock-names property.
> > > > +
> > > > +- clock-names: must contain
> > > > +		"gate": for DE activation
> > > > +		"clock": DE clock
> > > 
> > > We've been calling them bus and mod.
> > 
> > I can understand "bus" (which is better than "apb"), but why "mod"?
> 
> Allwinner has been calling the clocks that are supposed to generate
> the external signals (depending on where you were looking) module or
> mod clocks (which is also why we have mod in the clock
> compatibles). The module 1 clocks being used for the audio and the
> module 0 for the rest (SPI, MMC, NAND, display, etc.)

I did not find any 'module' in the H3 documentation.
So, is it really a good name?

> > > > +
> > > > +- resets: phandle to the reset of the device
> > > > +
> > > > +- ports: phandle's to the LCD ports
> > > 
> > > Please use the OF graph.
> > 
> > These ports are references to the graph of nodes. See
> > 	http://www.kernelhub.org/?msg=911825&p=2
> 
> In an OF-graph, your phandle to the LCD controller would be replaced
> by an output endpoint.

This is the DE controller. There is no endpoint link at this level.
The Device Engine just handles the planes of the LCDs, but, indeed,
the LCDs must know about the DE and the DE must know about the LCDs.
There are 2 ways to realize this knowledge in the DT:
1) either the DE has one or two phandle's to the LCDs,
2) or the LCDs have a phandle to the DE.

I chose the 1st way, the DE ports pointing to the endpoint of the LCDs
which is part of the video link (OF-graph LCD <-> connector).
It would be possible to have phandles to the LCDs themselves, but this
asks for more code.

The second way is also possible, but it also complexifies a bit the
exchanges DE <-> LCD.

> > 	[snip]
> > > > +struct tcon {
> > > > +	u32 gctl;
> > > > +#define		TCON_GCTL_TCON_En BIT(31)
	[snip]
> > > > +	u32 fill_ctl;				/* 0x300 */
> > > > +	u32 fill_start0;
> > > > +	u32 fill_end0;
> > > > +	u32 fill_data0;
> > > > +};
> > > 
> > > Please use defines instead of the structures.
> > 
> > I think that structures are more readable.
> 
> That's not really the point. No one in the kernel uses it (and even
> you use defines for registers offset in some places of that
> patch). And then you have André arguments.

I am not convinced, but I'll do as you said.

> > > > +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> > > > +{
> > > > +	struct priv *priv = drm->dev_private;
> > > > +	struct lcd *lcd = priv->lcds[crtc];
> > > > +
> > > > +	tcon_write(lcd->mmio, gint0,
> > > > +			 tcon_read(lcd->mmio, gint0) &
> > > > +					~TCON_GINT0_TCON1_Vb_Int_En);
> > > > +}
> > > > +
> > > > +/* panel functions */
> > > 
> > > Panel functions? In the CRTC driver?
> > 
> > Yes, dumb panel.
> 
> What do you mean by that? Using a Parallel/RGB interface?

Sorry, I though this was a well-known name. The 'dump panel' was used
in the documentation of my previous ARM machine as the video frame sent
to the HDMI controller. 'video_frame' is OK for you?

	[snip]
> > > > +	ret = clk_prepare_enable(lcd->clk);
> > > > +	if (ret)
> > > > +		goto err2;
> > > 
> > > Is there any reason not to do that in the enable / disable? Leaving
> > > clocks running while the device has no guarantee that it's going to be
> > > used seems like a waste of resources.
> > 
> > If the machine does not need video (network server, router..), it is simpler
> > to prevent the video driver to be loaded (DT, module black list...).
> 
> You might not have control on any of it, or you might just have no
> monitor attached for example. Recompiling the kernel or updating the
> DT when you want to plug an HDMI monitor seems like a poor UX :)

OK, I will check if this works.

> > > > +static const struct {
> > > > +	char chan;
> > > > +	char layer;
> > > > +	char pipe;
> > > > +} plane2layer[DE2_N_PLANES] = {
> > > > +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> > > > +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> > > > +	[DE2_VI_PLANE] =	{0, 1, 0},
> > > > +};
> > > 
> > > Comments?
> > 
> > This
> > 	primary plane is channel 0 (VI), layer 0, pipe 0
> > 	cursor plane is channel 1 (UI), layer 0, pipe 1
> > 	overlay plane is channel 0 (VI), layer 1, pipe 0
> > or the full explanation:
> >     Constraints:
> > 	The VI channels can do RGB or YUV, while UI channels can do RGB
> > 	only.
> > 	The LCD 0 has 1 VI channel and 4 UI channels, while
> > 	LCD 1 has only 1 VI channel and 1 UI channel.
> > 	The cursor must go to a channel bigger than the primary channel,
> > 	otherwise it is not transparent.
> >     First try:
> > 	Letting the primary plane (usually RGB) in the 2nd channel (UI),
> > 	as this is done in the legacy driver, asks for the cursor to go
> > 	to the next channel (UI), but this one does not exist in LCD1.
> >     Retained layout:
> > 	So, we must use only 2 channels for the same behaviour on LCD0
> > 	(H3) and LCD1 (A83T)
> > 	The retained combination is:
> > 		- primary plane in the first channel (VI),
> > 		- cursor plane inthe 2nd channel (UI), and
> > 		- overlay plane in the 1st channel (VI).
> > 
> > 	Note that there could be 3 overlay planes (a channel has 4
> > 	layers), but I am not sure that the A83T or the H3 could
> > 	support 3 simultaneous video streams...
> 
> Do you know if the pipe works in the old display engine?
> 
> Especially about the two-steps composition that wouldn't allow you to
> have alpha on all the planes?
> 
> If it is similar, I think hardcoding the pipe number is pretty bad,
> because that would restrict the combination of planes and formats,
> while some other might have worked.

From what I understood about the DE2, the pipes just define the priority
of the overlay channels (one pipe for one channel).
With the cursor constraint, there must be at least 2 channels in
order (primary, cursor). Then, with these 2 channels/pipes, there can be
6 so-called overlay planes (3 RGB/YUV and 3 RGB only).
Enabling the pipes 2 and 3 (LCD 0 only) would offer 8 more planes, but
RGB only. Then, it might be useful to have dynamic pipes.

	[snip]
> > > > +void de2_de_plane_update(struct priv *priv,
> > > > +			int lcd_num, int plane_ix,
> > > > +			struct drm_plane_state *state,
> > > > +			struct drm_plane_state *old_state)
> > > > +{
> > > > +	struct drm_framebuffer *fb = state->fb;
> > > > +	struct drm_gem_cma_object *gem;
> > > > +	void __iomem *mux_o = priv->mmio;
> > > > +	void __iomem *chan_o;
> > > > +	u32 size = WH(state->crtc_w, state->crtc_h);
> > > > +	u32 coord;
> > > > +	u32 screen_size;
> > > > +	u32 data, fcolor;
> > > > +	u32 ui_sel, alpha_glob;
> > > > +	int chan, layer, x, y;
> > > > +	unsigned fmt;
> > > > +	unsigned long flags;
> > > > +
> > > > +	chan = plane2layer[plane_ix].chan;
> > > > +	layer = plane2layer[plane_ix].layer;
> > > > +
> > > > +	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
> > > > +	chan_o = mux_o;
> > > > +	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
> > > > +
> > > > +	x = state->crtc_x >= 0 ? state->crtc_x : 0;
> > > > +	y = state->crtc_y >= 0 ? state->crtc_y : 0;
> > > > +	coord = XY(x, y);
> > > > +
> > > > +	/* handle the cursor move */
> > > > +	if (plane_ix == DE2_CURSOR_PLANE
> > > > +	 && fb == old_state->fb) {
> > > > +		spin_lock_irqsave(&de_lock, flags);
> > > > +		de_lcd_select(priv, lcd_num, mux_o);
> > > > +		if (chan == 0)
> > > > +			vi_write(chan_o, cfg[layer].coord, coord);
> > > > +		else
> > > > +			ui_write(chan_o, cfg[layer].coord, coord);
> > > > +		spin_unlock_irqrestore(&de_lock, flags);
> > > > +		return;
> > > > +	}
> > > > +
> > > > +	gem = drm_fb_cma_get_gem_obj(fb, 0);
> > > > +
> > > > +	ui_sel = alpha_glob = 0;
> > > > +	switch (fb->pixel_format) {
> > > > +	case DRM_FORMAT_ARGB8888:
> > > > +		fmt = DE2_FORMAT_ARGB_8888;
> > > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > > +		break;
> > > > +	case DRM_FORMAT_BGRA8888:
> > > > +		fmt = DE2_FORMAT_BGRA_8888;
> > > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > > +		break;
> > > > +	case DRM_FORMAT_XRGB8888:
> > > > +		fmt = DE2_FORMAT_XRGB_8888;
> > > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > > +		alpha_glob = (1 << UI_CFG_ATTR_alpmod_SHIFT) |
> > > > +				(0xff << UI_CFG_ATTR_alpha_SHIFT);
> > > > +		break;
> > > > +	case DRM_FORMAT_RGB888:
> > > > +		fmt = DE2_FORMAT_RGB_888;
> > > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > > +		break;
> > > > +	case DRM_FORMAT_BGR888:
> > > > +		fmt = DE2_FORMAT_BGR_888;
> > > > +		ui_sel = VI_CFG_ATTR_ui_sel;
> > > > +		break;
> > > > +	case DRM_FORMAT_YUYV:
> > > > +		fmt = DE2_FORMAT_YUV422_I_YUYV;
> > > > +		break;
> > > > +	case DRM_FORMAT_YVYU:
> > > > +		fmt = DE2_FORMAT_YUV422_I_YVYU;
> > > > +		break;
> > > > +	case DRM_FORMAT_YUV422:
> > > > +		fmt = DE2_FORMAT_YUV422_P;
> > > > +		break;
> > > > +	case DRM_FORMAT_YUV420:
> > > > +		fmt = DE2_FORMAT_YUV420_P;
> > > > +		break;
> > > > +	case DRM_FORMAT_UYVY:
> > > > +		fmt = DE2_FORMAT_YUV422_I_UYVY;
> > > > +		break;
> > > > +	default:
> > > > +		pr_err("format %.4s not yet treated\n",
> > > > +			(char *) &fb->pixel_format);
> > > > +		return;
> > > > +	}
> > > > +
> > > > +	spin_lock_irqsave(&de_lock, flags);
> > > > +
> > > > +	screen_size = plane_ix == DE2_PRIMARY_PLANE ?
> > > > +			size :
> > > > +			glb_read(mux_o + DE_MUX_GLB_REGS, size);
> > > > +
> > > > +	/* prepare the activation of alpha blending (1 bit per plane) */
> > > > +	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl)
> > > > +			| (0x100 << plane2layer[plane_ix].pipe);
> > > > +
> > > > +	de_lcd_select(priv, lcd_num, mux_o);
> > > > +
> > > > +	if (chan == 0) {	/* VI channel */
> > > > +		int i;
> > > > +
> > > > +		data = VI_CFG_ATTR_en | (fmt << VI_CFG_ATTR_fmt_SHIFT) |
> > > > +					ui_sel;
> > > > +		vi_write(chan_o, cfg[layer].attr, data);
> > > > +		vi_write(chan_o, cfg[layer].size, size);
> > > > +		vi_write(chan_o, cfg[layer].coord, coord);
> > > > +		for (i = 0; i < VI_N_PLANES; i++) {
> > > > +			vi_write(chan_o, cfg[layer].pitch[i],
> > > > +					fb->pitches[i] ? fb->pitches[i] :
> > > > +							fb->pitches[0]);
> > > > +			vi_write(chan_o, cfg[layer].top_laddr[i],
> > > > +				gem->paddr + fb->offsets[i]);
> > > > +			vi_write(chan_o, fcolor[layer], 0xff000000);
> > > > +		}
> > > > +		if (layer == 0)
> > > > +			vi_write(chan_o, ovl_size[0], screen_size);
> > > > +
> > > > +	} else {		/* UI channel */
> > > > +		data = UI_CFG_ATTR_en | (fmt << UI_CFG_ATTR_fmt_SHIFT) |
> > > > +			alpha_glob;
> > > > +		ui_write(chan_o, cfg[layer].attr, data);
> > > > +		ui_write(chan_o, cfg[layer].size, size);
> > > > +		ui_write(chan_o, cfg[layer].coord, coord);
> > > > +		ui_write(chan_o, cfg[layer].pitch, fb->pitches[0]);
> > > > +		ui_write(chan_o, cfg[layer].top_laddr,
> > > > +				gem->paddr + fb->offsets[0]);
> > > > +		if (layer == 0)
> > > > +			ui_write(chan_o, ovl_size, screen_size);
> > > > +	}
> > > > +	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, fcolor);
> > > > +
> > > > +	spin_unlock_irqrestore(&de_lock, flags);
> > > > +}
> > > 
> > > Splitting that into functions would make it a bit more trivial and
> > > readable.
> > 
> > Not sure: there is a lot of common data and different I/O accesses.
> 
> You could still have different ones to set the buffers, formats and
> coordinates for example.

I will have a look...

	[snip]
> > > > +static int __init de2_drm_init(void)
> > > > +{
> > > > +	int ret;
> > > > +
> > > > +/* uncomment to activate the drm traces at startup time */
> > > > +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> > > > +			DRM_UT_PRIME | DRM_UT_ATOMIC; */
> > > 
> > > That's useless.
> > 
> > Right, but it seems that some people don't know how to debug a DRM
> > driver. This is only a reminder.
> > 
> > > > +	DRM_DEBUG_DRIVER("\n");
> > > > +
> > > > +	ret = platform_driver_register(&de2_lcd_platform_driver);
> > > > +	if (ret < 0)
> > > > +		return ret;
> > > > +
> > > > +	ret = platform_driver_register(&de2_drm_platform_driver);
> > > > +	if (ret < 0)
> > > > +		platform_driver_unregister(&de2_lcd_platform_driver);
> > > > +
> > > > +	return ret;
> > > > +}
> > > 
> > > And that really shouldn't be done that way.
> > 
> > May you explain?
> 
> This goes against the whole idea of the device and driver
> model. Drivers should only register themselves, device should be
> created by buses (or by using some external components if the bus
> can't: DT, ACPI, etc.). If there's a match, you get probed.
> 
> A driver that creates its own device just to probe itself violates
> that.

In this function (module init), there is no driver yet.
The module contains 2 drivers: the DE (planes) and the LCD (CRTC),
and there is no macro to handle such modules.

> > > > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> > > > +{
> > > > +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> > > > +
> > > > +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> > > > +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > +	if (ret >= 0)
> > > > +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> > > > +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > 
> > > Nothing looks really special about that cursor plane. Any reasion not
> > > to make it an overlay?
> > 
> > As explained above (channel/layer/pipe plane definitions), the cursor
> > cannot go in a channel lower or equal to the one of the primary plane.
> > Then, it must be known and, so, have an explicit plane.
> 
> If you were to make it a plane, you could use atomic_check to check
> this and make sure this doesn't happen. And you would gain a generic
> plane that can be used for other purposes if needed.

The function drm_crtc_init_with_planes() offers a cursor plane for free.
On the other side, having 6 overlay planes is more than the SoCs can
support.
Rob Herring Oct. 30, 2016, 8:41 p.m. UTC | #9
On Tue, Oct 25, 2016 at 04:14:41PM +0200, Jean-Francois Moine wrote:
> On Mon, 24 Oct 2016 16:04:19 +0200
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
> > Hi,
> 
> Hi Maxime,
> 
> > On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
> > > Allwinner's recent SoCs, as A64, A83T and H3, contain a new display
> > > engine, DE2.
> > > This patch adds a DRM video driver for this device.
> > > 
> > > Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
> > 
> > Output from checkpatch:
> > total: 0 errors, 20 warnings, 83 checks, 1799 lines checked
> > 
> > > ---
> > >  .../bindings/display/sunxi/sunxi-de2.txt           |  83 +++
> > >  drivers/gpu/drm/Kconfig                            |   2 +
> > >  drivers/gpu/drm/Makefile                           |   1 +
> > >  drivers/gpu/drm/sunxi/Kconfig                      |  21 +
> > >  drivers/gpu/drm/sunxi/Makefile                     |   7 +
> > >  drivers/gpu/drm/sunxi/de2_crtc.c                   | 475 +++++++++++++++++
> > >  drivers/gpu/drm/sunxi/de2_crtc.h                   |  63 +++
> > >  drivers/gpu/drm/sunxi/de2_de.c                     | 591 +++++++++++++++++++++
> > >  drivers/gpu/drm/sunxi/de2_drm.h                    |  47 ++
> > >  drivers/gpu/drm/sunxi/de2_drv.c                    | 378 +++++++++++++
> > >  drivers/gpu/drm/sunxi/de2_plane.c                  | 119 +++++
> > >  11 files changed, 1787 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> > >  create mode 100644 drivers/gpu/drm/sunxi/Kconfig
> > >  create mode 100644 drivers/gpu/drm/sunxi/Makefile
> > >  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.c
> > >  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.h
> > >  create mode 100644 drivers/gpu/drm/sunxi/de2_de.c
> > >  create mode 100644 drivers/gpu/drm/sunxi/de2_drm.h
> > >  create mode 100644 drivers/gpu/drm/sunxi/de2_drv.c
> > >  create mode 100644 drivers/gpu/drm/sunxi/de2_plane.c
> > > 
> > > diff --git a/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> > > new file mode 100644
> > > index 0000000..f9cd67a
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt

[...]

> > > +
> > > +- resets: phandle to the reset of the device
> > > +
> > > +- ports: phandle's to the LCD ports
> > 
> > Please use the OF graph.
> 
> These ports are references to the graph of nodes. See
> 	http://www.kernelhub.org/?msg=911825&p=2

I think what Maxime means is describe the DE to LCD connection with OF 
graph, not just a phandle.

Rob
Rob Herring Oct. 30, 2016, 8:41 p.m. UTC | #10
On Fri, Oct 21, 2016 at 09:26:18AM +0200, Jean-Francois Moine wrote:
> Allwinner's recent SoCs, as A64, A83T and H3, contain a new display
> engine, DE2.
> This patch adds a DRM video driver for this device.
> 
> Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
> ---
>  .../bindings/display/sunxi/sunxi-de2.txt           |  83 +++
>  drivers/gpu/drm/Kconfig                            |   2 +
>  drivers/gpu/drm/Makefile                           |   1 +
>  drivers/gpu/drm/sunxi/Kconfig                      |  21 +
>  drivers/gpu/drm/sunxi/Makefile                     |   7 +
>  drivers/gpu/drm/sunxi/de2_crtc.c                   | 475 +++++++++++++++++
>  drivers/gpu/drm/sunxi/de2_crtc.h                   |  63 +++
>  drivers/gpu/drm/sunxi/de2_de.c                     | 591 +++++++++++++++++++++
>  drivers/gpu/drm/sunxi/de2_drm.h                    |  47 ++
>  drivers/gpu/drm/sunxi/de2_drv.c                    | 378 +++++++++++++
>  drivers/gpu/drm/sunxi/de2_plane.c                  | 119 +++++
>  11 files changed, 1787 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
>  create mode 100644 drivers/gpu/drm/sunxi/Kconfig
>  create mode 100644 drivers/gpu/drm/sunxi/Makefile
>  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.c
>  create mode 100644 drivers/gpu/drm/sunxi/de2_crtc.h
>  create mode 100644 drivers/gpu/drm/sunxi/de2_de.c
>  create mode 100644 drivers/gpu/drm/sunxi/de2_drm.h
>  create mode 100644 drivers/gpu/drm/sunxi/de2_drv.c
>  create mode 100644 drivers/gpu/drm/sunxi/de2_plane.c
> 
> diff --git a/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
> new file mode 100644
> index 0000000..f9cd67a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt

> +	hdmi: hdmi@01ee0000 {
> +		...
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		port {
> +			type = "video";

This is proposed, but not an accepted property. Please drop.

> +			hdmi_ep: endpoint {
> +				remote-endpoint = <&lcd0_ep>;
> +			};
> +		};
> +	};
Maxime Ripard Nov. 7, 2016, 10:37 p.m. UTC | #11
Hi,

On Fri, Oct 28, 2016 at 07:34:20PM +0200, Jean-Francois Moine wrote:
> On Fri, 28 Oct 2016 00:03:16 +0200
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
> > On Tue, Oct 25, 2016 at 04:14:41PM +0200, Jean-Francois Moine wrote:
> > > > > +Display controller
> > > > > +==================
> > > > > +
> > > > > +Required properties:
> > > > > +
> > > > > +- compatible: value should be one of the following
> > > > > +		"allwinner,sun8i-a83t-display-engine"
> > > > > +		"allwinner,sun8i-h3-display-engine"
> > > > > +
> > > > > +- clocks: must include clock specifiers corresponding to entries in the
> > > > > +		clock-names property.
> > > > > +
> > > > > +- clock-names: must contain
> > > > > +		"gate": for DE activation
> > > > > +		"clock": DE clock
> > > > 
> > > > We've been calling them bus and mod.
> > > 
> > > I can understand "bus" (which is better than "apb"), but why "mod"?
> > 
> > Allwinner has been calling the clocks that are supposed to generate
> > the external signals (depending on where you were looking) module or
> > mod clocks (which is also why we have mod in the clock
> > compatibles). The module 1 clocks being used for the audio and the
> > module 0 for the rest (SPI, MMC, NAND, display, etc.)
> 
> I did not find any 'module' in the H3 documentation.
> So, is it really a good name?

It's true that they use it less nowadays, but they still do,
ie. https://github.com/allwinner-zh/linux-3.4-sunxi/blob/master/drivers/clk/sunxi/clk-sun8iw7.c#L513

And we have to remain consistent anyway.

> > > > > +
> > > > > +- resets: phandle to the reset of the device
> > > > > +
> > > > > +- ports: phandle's to the LCD ports
> > > > 
> > > > Please use the OF graph.
> > > 
> > > These ports are references to the graph of nodes. See
> > > 	http://www.kernelhub.org/?msg=911825&p=2
> > 
> > In an OF-graph, your phandle to the LCD controller would be replaced
> > by an output endpoint.
> 
> This is the DE controller. There is no endpoint link at this level.

The display engine definitely has an endpoint: the TCON.

> The Device Engine just handles the planes of the LCDs, but, indeed,
> the LCDs must know about the DE and the DE must know about the LCDs.
> There are 2 ways to realize this knowledge in the DT:
> 1) either the DE has one or two phandle's to the LCDs,
> 2) or the LCDs have a phandle to the DE.
> 
> I chose the 1st way, the DE ports pointing to the endpoint of the LCDs
> which is part of the video link (OF-graph LCD <-> connector).
> It would be possible to have phandles to the LCDs themselves, but this
> asks for more code.
> 
> The second way is also possible, but it also complexifies a bit the
> exchanges DE <-> LCD.

I'm still not sure how it would complexify anything, and why you can't
use the display graph to model the relation between the display engine
and the TCON (and why you want to use a generic property that refers
to the of-graph while it really isn't).

> > > > > +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> > > > > +{
> > > > > +	struct priv *priv = drm->dev_private;
> > > > > +	struct lcd *lcd = priv->lcds[crtc];
> > > > > +
> > > > > +	tcon_write(lcd->mmio, gint0,
> > > > > +			 tcon_read(lcd->mmio, gint0) &
> > > > > +					~TCON_GINT0_TCON1_Vb_Int_En);
> > > > > +}
> > > > > +
> > > > > +/* panel functions */
> > > > 
> > > > Panel functions? In the CRTC driver?
> > > 
> > > Yes, dumb panel.
> > 
> > What do you mean by that? Using a Parallel/RGB interface?
> 
> Sorry, I though this was a well-known name. The 'dump panel' was used
> in the documentation of my previous ARM machine as the video frame sent
> to the HDMI controller. 'video_frame' is OK for you?

If it's the frame sent to the encoder, then it would be the CRTC by
DRM's nomenclature.

> > > > > +static const struct {
> > > > > +	char chan;
> > > > > +	char layer;
> > > > > +	char pipe;
> > > > > +} plane2layer[DE2_N_PLANES] = {
> > > > > +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> > > > > +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> > > > > +	[DE2_VI_PLANE] =	{0, 1, 0},
> > > > > +};
> > > > 
> > > > Comments?
> > > 
> > > This
> > > 	primary plane is channel 0 (VI), layer 0, pipe 0
> > > 	cursor plane is channel 1 (UI), layer 0, pipe 1
> > > 	overlay plane is channel 0 (VI), layer 1, pipe 0
> > > or the full explanation:
> > >     Constraints:
> > > 	The VI channels can do RGB or YUV, while UI channels can do RGB
> > > 	only.
> > > 	The LCD 0 has 1 VI channel and 4 UI channels, while
> > > 	LCD 1 has only 1 VI channel and 1 UI channel.
> > > 	The cursor must go to a channel bigger than the primary channel,
> > > 	otherwise it is not transparent.
> > >     First try:
> > > 	Letting the primary plane (usually RGB) in the 2nd channel (UI),
> > > 	as this is done in the legacy driver, asks for the cursor to go
> > > 	to the next channel (UI), but this one does not exist in LCD1.
> > >     Retained layout:
> > > 	So, we must use only 2 channels for the same behaviour on LCD0
> > > 	(H3) and LCD1 (A83T)
> > > 	The retained combination is:
> > > 		- primary plane in the first channel (VI),
> > > 		- cursor plane inthe 2nd channel (UI), and
> > > 		- overlay plane in the 1st channel (VI).
> > > 
> > > 	Note that there could be 3 overlay planes (a channel has 4
> > > 	layers), but I am not sure that the A83T or the H3 could
> > > 	support 3 simultaneous video streams...
> > 
> > Do you know if the pipe works in the old display engine?
> > 
> > Especially about the two-steps composition that wouldn't allow you to
> > have alpha on all the planes?
> > 
> > If it is similar, I think hardcoding the pipe number is pretty bad,
> > because that would restrict the combination of planes and formats,
> > while some other might have worked.
> 
> From what I understood about the DE2, the pipes just define the priority
> of the overlay channels (one pipe for one channel).
> With the cursor constraint, there must be at least 2 channels in
> order (primary, cursor). Then, with these 2 channels/pipes, there can be
> 6 so-called overlay planes (3 RGB/YUV and 3 RGB only).
> Enabling the pipes 2 and 3 (LCD 0 only) would offer 8 more planes, but
> RGB only. Then, it might be useful to have dynamic pipes.

That's very valuable (and definitely should go into a comment),
thanks!

I still believe that's it should be into a (simple at first)
atomic_check. That would be easier to extend and quite easy to
document and get simply by looking at the code.

> > > > > +static int __init de2_drm_init(void)
> > > > > +{
> > > > > +	int ret;
> > > > > +
> > > > > +/* uncomment to activate the drm traces at startup time */
> > > > > +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> > > > > +			DRM_UT_PRIME | DRM_UT_ATOMIC; */
> > > > 
> > > > That's useless.
> > > 
> > > Right, but it seems that some people don't know how to debug a DRM
> > > driver. This is only a reminder.
> > > 
> > > > > +	DRM_DEBUG_DRIVER("\n");
> > > > > +
> > > > > +	ret = platform_driver_register(&de2_lcd_platform_driver);
> > > > > +	if (ret < 0)
> > > > > +		return ret;
> > > > > +
> > > > > +	ret = platform_driver_register(&de2_drm_platform_driver);
> > > > > +	if (ret < 0)
> > > > > +		platform_driver_unregister(&de2_lcd_platform_driver);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > 
> > > > And that really shouldn't be done that way.
> > > 
> > > May you explain?
> > 
> > This goes against the whole idea of the device and driver
> > model. Drivers should only register themselves, device should be
> > created by buses (or by using some external components if the bus
> > can't: DT, ACPI, etc.). If there's a match, you get probed.
> > 
> > A driver that creates its own device just to probe itself violates
> > that.
> 
> In this function (module init), there is no driver yet.
> The module contains 2 drivers: the DE (planes) and the LCD (CRTC),
> and there is no macro to handle such modules.

Ah, yes, my bad. I thought you were registering a device and a
driver. Still this is a very unusual pattern. Why do you need to split
the two? Can't you just merge them?

> > > > > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> > > > > +{
> > > > > +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> > > > > +
> > > > > +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> > > > > +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> > > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > > +	if (ret >= 0)
> > > > > +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> > > > > +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> > > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > 
> > > > Nothing looks really special about that cursor plane. Any reasion not
> > > > to make it an overlay?
> > > 
> > > As explained above (channel/layer/pipe plane definitions), the cursor
> > > cannot go in a channel lower or equal to the one of the primary plane.
> > > Then, it must be known and, so, have an explicit plane.
> > 
> > If you were to make it a plane, you could use atomic_check to check
> > this and make sure this doesn't happen. And you would gain a generic
> > plane that can be used for other purposes if needed.
> 
> The function drm_crtc_init_with_planes() offers a cursor plane for free.
> On the other side, having 6 overlay planes is more than the SoCs can
> support.

It's not really for free, it costs you a generic plane that could
definitely be used for something else and cannot anymore because
they've been hardcoded to a cursor.

And having a camera, the VPU or even an application directly output
directly into one of these planes seems a much better use of a generic
plane than a cursor.

Maxime
Jean-Francois Moine Nov. 8, 2016, 2:37 p.m. UTC | #12
On Mon, 7 Nov 2016 23:37:41 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> Hi,
> 
> On Fri, Oct 28, 2016 at 07:34:20PM +0200, Jean-Francois Moine wrote:
> > On Fri, 28 Oct 2016 00:03:16 +0200
> > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
	[snip]
> > > > > We've been calling them bus and mod.
> > > > 
> > > > I can understand "bus" (which is better than "apb"), but why "mod"?
> > > 
> > > Allwinner has been calling the clocks that are supposed to generate
> > > the external signals (depending on where you were looking) module or
> > > mod clocks (which is also why we have mod in the clock
> > > compatibles). The module 1 clocks being used for the audio and the
> > > module 0 for the rest (SPI, MMC, NAND, display, etc.)
> > 
> > I did not find any 'module' in the H3 documentation.
> > So, is it really a good name?
> 
> It's true that they use it less nowadays, but they still do,
> ie. https://github.com/allwinner-zh/linux-3.4-sunxi/blob/master/drivers/clk/sunxi/clk-sun8iw7.c#L513

There is a 'mod' suffix, but it is used for the bus gates only, not for
the main clocks.

> And we have to remain consistent anyway.

I don't see any consistency in the H3 DT:
- the bus gates are named "ahb" and apb"
- the (main) clocks are named "mmc", "usb0_phy" and "ir"
There is no "bus" nor "mod".

> > > > > > +
> > > > > > +- resets: phandle to the reset of the device
> > > > > > +
> > > > > > +- ports: phandle's to the LCD ports
> > > > > 
> > > > > Please use the OF graph.
> > > > 
> > > > These ports are references to the graph of nodes. See
> > > > 	http://www.kernelhub.org/?msg=911825&p=2
> > > 
> > > In an OF-graph, your phandle to the LCD controller would be replaced
> > > by an output endpoint.
> > 
> > This is the DE controller. There is no endpoint link at this level.
> 
> The display engine definitely has an endpoint: the TCON.

Not at all. The video chain is simply
	CRTC (TCON) -> connector (HDMI/LCD/DAC/..)
The DE is an ancillary device which handles the planes.

> > The Device Engine just handles the planes of the LCDs, but, indeed,
> > the LCDs must know about the DE and the DE must know about the LCDs.
> > There are 2 ways to realize this knowledge in the DT:
> > 1) either the DE has one or two phandle's to the LCDs,
> > 2) or the LCDs have a phandle to the DE.
> > 
> > I chose the 1st way, the DE ports pointing to the endpoint of the LCDs
> > which is part of the video link (OF-graph LCD <-> connector).
> > It would be possible to have phandles to the LCDs themselves, but this
> > asks for more code.
> > 
> > The second way is also possible, but it also complexifies a bit the
> > exchanges DE <-> LCD.
> 
> I'm still not sure how it would complexify anything, and why you can't
> use the display graph to model the relation between the display engine
> and the TCON (and why you want to use a generic property that refers
> to the of-graph while it really isn't).

Complexification:
1- my solution:
  At startup time, the DE device is the DRM device. It has to know the
  devices entering in the video chains.
  The CRTCs (LCD/TCON) are found by
	ports[i] -> parent
  The connectors are found by
	ports[i] -> endpoint -> remote_endpoint -> parent
2- with ports pointing to the LCDs:
  The CRTCs (LCD/TCON) are simply
	ports[i]
  The connectors are found by
	loop on all ports of ports[i]
		ports[i][j] -> endpoint -> remote_endpoint -> parent
3- with a phandle to the DE in the LCDs:
  The DE cannot be the DRM device because there is no information about
  the video devices in the DT. Then, the DRM devices are the LCDs.
  These LCDs must give their indices to the DE. So, the DE must implement
  some callback function to accept a LCD definition, and there must be
  a list of DEs in the driver to make the association DE <-> LCD[i]
  Some more problem may be raised if a user wants to have the same frame
  buffer on the 2 LCDs of a DE.

Anyway, my solution is already used in the IMX Soc.
See 'display-subsystem' in arch/arm/boot/dts/imx6q.dtsi for an example.

> > > > > > +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> > > > > > +{
> > > > > > +	struct priv *priv = drm->dev_private;
> > > > > > +	struct lcd *lcd = priv->lcds[crtc];
> > > > > > +
> > > > > > +	tcon_write(lcd->mmio, gint0,
> > > > > > +			 tcon_read(lcd->mmio, gint0) &
> > > > > > +					~TCON_GINT0_TCON1_Vb_Int_En);
> > > > > > +}
> > > > > > +
> > > > > > +/* panel functions */
> > > > > 
> > > > > Panel functions? In the CRTC driver?
> > > > 
> > > > Yes, dumb panel.
> > > 
> > > What do you mean by that? Using a Parallel/RGB interface?
> > 
> > Sorry, I though this was a well-known name. The 'dump panel' was used
> > in the documentation of my previous ARM machine as the video frame sent
> > to the HDMI controller. 'video_frame' is OK for you?
> 
> If it's the frame sent to the encoder, then it would be the CRTC by
> DRM's nomenclature.

The CRTC is a software entity. The frame buffer is a hardware entity.

> > > > > > +static const struct {
> > > > > > +	char chan;
> > > > > > +	char layer;
> > > > > > +	char pipe;
> > > > > > +} plane2layer[DE2_N_PLANES] = {
> > > > > > +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> > > > > > +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> > > > > > +	[DE2_VI_PLANE] =	{0, 1, 0},
> > > > > > +};
	[snip]
> > > > > 
> > > > > Comments?
> > > > 
> > > > This
> > > > 	primary plane is channel 0 (VI), layer 0, pipe 0
> > > > 	cursor plane is channel 1 (UI), layer 0, pipe 1
> > > > 	overlay plane is channel 0 (VI), layer 1, pipe 0
> > > > or the full explanation:
> > > >     Constraints:
> > > > 	The VI channels can do RGB or YUV, while UI channels can do RGB
> > > > 	only.
> > > > 	The LCD 0 has 1 VI channel and 4 UI channels, while
> > > > 	LCD 1 has only 1 VI channel and 1 UI channel.
> > > > 	The cursor must go to a channel bigger than the primary channel,
> > > > 	otherwise it is not transparent.
> > > >     First try:
> > > > 	Letting the primary plane (usually RGB) in the 2nd channel (UI),
> > > > 	as this is done in the legacy driver, asks for the cursor to go
> > > > 	to the next channel (UI), but this one does not exist in LCD1.
> > > >     Retained layout:
> > > > 	So, we must use only 2 channels for the same behaviour on LCD0
> > > > 	(H3) and LCD1 (A83T)
> > > > 	The retained combination is:
> > > > 		- primary plane in the first channel (VI),
> > > > 		- cursor plane inthe 2nd channel (UI), and
> > > > 		- overlay plane in the 1st channel (VI).
> > > > 
> > > > 	Note that there could be 3 overlay planes (a channel has 4
> > > > 	layers), but I am not sure that the A83T or the H3 could
> > > > 	support 3 simultaneous video streams...
> > > 
> > > Do you know if the pipe works in the old display engine?
> > > 
> > > Especially about the two-steps composition that wouldn't allow you to
> > > have alpha on all the planes?
> > > 
> > > If it is similar, I think hardcoding the pipe number is pretty bad,
> > > because that would restrict the combination of planes and formats,
> > > while some other might have worked.
> > 
> > From what I understood about the DE2, the pipes just define the priority
> > of the overlay channels (one pipe for one channel).
> > With the cursor constraint, there must be at least 2 channels in
> > order (primary, cursor). Then, with these 2 channels/pipes, there can be
> > 6 so-called overlay planes (3 RGB/YUV and 3 RGB only).
> > Enabling the pipes 2 and 3 (LCD 0 only) would offer 8 more planes, but
> > RGB only. Then, it might be useful to have dynamic pipes.
> 
> That's very valuable (and definitely should go into a comment),
> thanks!
> 
> I still believe that's it should be into a (simple at first)
> atomic_check. That would be easier to extend and quite easy to
> document and get simply by looking at the code.

Sorry for I don't understand what you mean.

> > > > > > +static int __init de2_drm_init(void)
> > > > > > +{
> > > > > > +	int ret;
> > > > > > +
> > > > > > +/* uncomment to activate the drm traces at startup time */
> > > > > > +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> > > > > > +			DRM_UT_PRIME | DRM_UT_ATOMIC; */
> > > > > 
> > > > > That's useless.
> > > > 
> > > > Right, but it seems that some people don't know how to debug a DRM
> > > > driver. This is only a reminder.
> > > > 
> > > > > > +	DRM_DEBUG_DRIVER("\n");
> > > > > > +
> > > > > > +	ret = platform_driver_register(&de2_lcd_platform_driver);
> > > > > > +	if (ret < 0)
> > > > > > +		return ret;
> > > > > > +
> > > > > > +	ret = platform_driver_register(&de2_drm_platform_driver);
> > > > > > +	if (ret < 0)
> > > > > > +		platform_driver_unregister(&de2_lcd_platform_driver);
> > > > > > +
> > > > > > +	return ret;
> > > > > > +}
> > > > > 
> > > > > And that really shouldn't be done that way.
> > > > 
> > > > May you explain?
> > > 
> > > This goes against the whole idea of the device and driver
> > > model. Drivers should only register themselves, device should be
> > > created by buses (or by using some external components if the bus
> > > can't: DT, ACPI, etc.). If there's a match, you get probed.
> > > 
> > > A driver that creates its own device just to probe itself violates
> > > that.
> > 
> > In this function (module init), there is no driver yet.
> > The module contains 2 drivers: the DE (planes) and the LCD (CRTC),
> > and there is no macro to handle such modules.
> 
> Ah, yes, my bad. I thought you were registering a device and a
> driver. Still this is a very unusual pattern. Why do you need to split
> the two? Can't you just merge them?

The DE and the LCDs are different devices on different drivers.
A DE must be only one device because it has to handle concurent
accesses from its 2 LCDs. Then 2 drivers.

But only one module. Why? Because there cannot be double direction
calls from one module to an other one, and, in our case, for example,
- the DRM (DE) device must call vblank functions which are handled in
  the CRTC (TCON) device, and
- the CRTC device must call DE initialization functions at startup time.

> > > > > > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> > > > > > +{
> > > > > > +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> > > > > > +
> > > > > > +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> > > > > > +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> > > > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > > > +	if (ret >= 0)
> > > > > > +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> > > > > > +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> > > > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > > 
> > > > > Nothing looks really special about that cursor plane. Any reasion not
> > > > > to make it an overlay?
> > > > 
> > > > As explained above (channel/layer/pipe plane definitions), the cursor
> > > > cannot go in a channel lower or equal to the one of the primary plane.
> > > > Then, it must be known and, so, have an explicit plane.
> > > 
> > > If you were to make it a plane, you could use atomic_check to check
> > > this and make sure this doesn't happen. And you would gain a generic
> > > plane that can be used for other purposes if needed.
> > 
> > The function drm_crtc_init_with_planes() offers a cursor plane for free.
> > On the other side, having 6 overlay planes is more than the SoCs can
> > support.
> 
> It's not really for free, it costs you a generic plane that could
> definitely be used for something else and cannot anymore because
> they've been hardcoded to a cursor.
> 
> And having a camera, the VPU or even an application directly output
> directly into one of these planes seems a much better use of a generic
> plane than a cursor.

Looking at the harder case (A83T), there may be 8 planes on 2 channels.
Using a primary plane and the cursor,
	8 planes - primary plane - cursor plane = 6 planes
6 planes are available.
If I count correctly, in your example:
	one camera + one VPU + one application = 3 planes
3 planes are used.
So, 3 planes are still available.

On the other side, removing the cursor would just let one more plane.
Do we really need this one? In other words, I'd be pleased to know how
you run 7 applications doing video overlay.
Maxime Ripard Nov. 16, 2016, 9:33 p.m. UTC | #13
On Tue, Nov 08, 2016 at 03:37:52PM +0100, Jean-Francois Moine wrote:
> On Mon, 7 Nov 2016 23:37:41 +0100
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
> > Hi,
> > 
> > On Fri, Oct 28, 2016 at 07:34:20PM +0200, Jean-Francois Moine wrote:
> > > On Fri, 28 Oct 2016 00:03:16 +0200
> > > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 	[snip]
> > > > > > We've been calling them bus and mod.
> > > > > 
> > > > > I can understand "bus" (which is better than "apb"), but why "mod"?
> > > > 
> > > > Allwinner has been calling the clocks that are supposed to generate
> > > > the external signals (depending on where you were looking) module or
> > > > mod clocks (which is also why we have mod in the clock
> > > > compatibles). The module 1 clocks being used for the audio and the
> > > > module 0 for the rest (SPI, MMC, NAND, display, etc.)
> > > 
> > > I did not find any 'module' in the H3 documentation.
> > > So, is it really a good name?
> > 
> > It's true that they use it less nowadays, but they still do,
> > ie. https://github.com/allwinner-zh/linux-3.4-sunxi/blob/master/drivers/clk/sunxi/clk-sun8iw7.c#L513
> 
> There is a 'mod' suffix, but it is used for the bus gates only, not for
> the main clocks.
> 
> > And we have to remain consistent anyway.
> 
> I don't see any consistency in the H3 DT:
> - the bus gates are named "ahb" and apb"

We've been inconsistent in the past, hence why it would be great to
have bus instead.

> - the (main) clocks are named "mmc", "usb0_phy" and "ir"
> There is no "bus" nor "mod".

Look into the other devices, for other SoCs. Pointing out that we've
been bad in the past doesn't mean that we can't improve.

> > > > > > > +
> > > > > > > +- resets: phandle to the reset of the device
> > > > > > > +
> > > > > > > +- ports: phandle's to the LCD ports
> > > > > > 
> > > > > > Please use the OF graph.
> > > > > 
> > > > > These ports are references to the graph of nodes. See
> > > > > 	http://www.kernelhub.org/?msg=911825&p=2
> > > > 
> > > > In an OF-graph, your phandle to the LCD controller would be replaced
> > > > by an output endpoint.
> > > 
> > > This is the DE controller. There is no endpoint link at this level.
> > 
> > The display engine definitely has an endpoint: the TCON.
> 
> Not at all. The video chain is simply
> 	CRTC (TCON) -> connector (HDMI/LCD/DAC/..)
> The DE is an ancillary device which handles the planes.

And what does it do exactly with those planes? It outputs it to the
TCON.

> > > The Device Engine just handles the planes of the LCDs, but, indeed,
> > > the LCDs must know about the DE and the DE must know about the LCDs.
> > > There are 2 ways to realize this knowledge in the DT:
> > > 1) either the DE has one or two phandle's to the LCDs,
> > > 2) or the LCDs have a phandle to the DE.
> > > 
> > > I chose the 1st way, the DE ports pointing to the endpoint of the LCDs
> > > which is part of the video link (OF-graph LCD <-> connector).
> > > It would be possible to have phandles to the LCDs themselves, but this
> > > asks for more code.
> > > 
> > > The second way is also possible, but it also complexifies a bit the
> > > exchanges DE <-> LCD.
> > 
> > I'm still not sure how it would complexify anything, and why you can't
> > use the display graph to model the relation between the display engine
> > and the TCON (and why you want to use a generic property that refers
> > to the of-graph while it really isn't).
> 
> Complexification:
> 1- my solution:
>   At startup time, the DE device is the DRM device.

How do you deal with SoCs with multiple display engines then?

> It has to know the devices entering in the video chains.
>   The CRTCs (LCD/TCON) are found by
> 	ports[i] -> parent
>   The connectors are found by
> 	ports[i] -> endpoint -> remote_endpoint -> parent
> 2- with ports pointing to the LCDs:
>   The CRTCs (LCD/TCON) are simply
> 	ports[i]
>   The connectors are found by
> 	loop on all ports of ports[i]
> 		ports[i][j] -> endpoint -> remote_endpoint -> parent
> 3- with a phandle to the DE in the LCDs:

What do you mean with LCD? Panels? Why would panels have a phandle to
the display engine?

>   The DE cannot be the DRM device because there is no information about
>   the video devices in the DT. Then, the DRM devices are the LCDs.
>   These LCDs must give their indices to the DE. So, the DE must implement
>   some callback function to accept a LCD definition, and there must be
>   a list of DEs in the driver to make the association DE <-> LCD[i]
>   Some more problem may be raised if a user wants to have the same frame
>   buffer on the 2 LCDs of a DE.

I have no idea what you're talking about, sorry.

> Anyway, my solution is already used in the IMX Soc.
> See 'display-subsystem' in arch/arm/boot/dts/imx6q.dtsi for an example.

Pointing out random example in the tree doesn't make a compelling
argument.

> > > > > > > +void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
> > > > > > > +{
> > > > > > > +	struct priv *priv = drm->dev_private;
> > > > > > > +	struct lcd *lcd = priv->lcds[crtc];
> > > > > > > +
> > > > > > > +	tcon_write(lcd->mmio, gint0,
> > > > > > > +			 tcon_read(lcd->mmio, gint0) &
> > > > > > > +					~TCON_GINT0_TCON1_Vb_Int_En);
> > > > > > > +}
> > > > > > > +
> > > > > > > +/* panel functions */
> > > > > > 
> > > > > > Panel functions? In the CRTC driver?
> > > > > 
> > > > > Yes, dumb panel.
> > > > 
> > > > What do you mean by that? Using a Parallel/RGB interface?
> > > 
> > > Sorry, I though this was a well-known name. The 'dump panel' was used
> > > in the documentation of my previous ARM machine as the video frame sent
> > > to the HDMI controller. 'video_frame' is OK for you?
> > 
> > If it's the frame sent to the encoder, then it would be the CRTC by
> > DRM's nomenclature.
> 
> The CRTC is a software entity. The frame buffer is a hardware entity.

Why are you about framebuffer now, this is nowhere in that
discussion. Any way, the framebuffer is also what is put in a plane,
so there's a name collision here, and you'll probably want to change
it.

Judging by the previous discussion, this should really be called
encoder if it encodes the frames on a bus format, or CRTC if it
composes the planes.

> > > > > > > +static const struct {
> > > > > > > +	char chan;
> > > > > > > +	char layer;
> > > > > > > +	char pipe;
> > > > > > > +} plane2layer[DE2_N_PLANES] = {
> > > > > > > +	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
> > > > > > > +	[DE2_CURSOR_PLANE] =	{1, 0, 1},
> > > > > > > +	[DE2_VI_PLANE] =	{0, 1, 0},
> > > > > > > +};
> 	[snip]
> > > > > > 
> > > > > > Comments?
> > > > > 
> > > > > This
> > > > > 	primary plane is channel 0 (VI), layer 0, pipe 0
> > > > > 	cursor plane is channel 1 (UI), layer 0, pipe 1
> > > > > 	overlay plane is channel 0 (VI), layer 1, pipe 0
> > > > > or the full explanation:
> > > > >     Constraints:
> > > > > 	The VI channels can do RGB or YUV, while UI channels can do RGB
> > > > > 	only.
> > > > > 	The LCD 0 has 1 VI channel and 4 UI channels, while
> > > > > 	LCD 1 has only 1 VI channel and 1 UI channel.
> > > > > 	The cursor must go to a channel bigger than the primary channel,
> > > > > 	otherwise it is not transparent.
> > > > >     First try:
> > > > > 	Letting the primary plane (usually RGB) in the 2nd channel (UI),
> > > > > 	as this is done in the legacy driver, asks for the cursor to go
> > > > > 	to the next channel (UI), but this one does not exist in LCD1.
> > > > >     Retained layout:
> > > > > 	So, we must use only 2 channels for the same behaviour on LCD0
> > > > > 	(H3) and LCD1 (A83T)
> > > > > 	The retained combination is:
> > > > > 		- primary plane in the first channel (VI),
> > > > > 		- cursor plane inthe 2nd channel (UI), and
> > > > > 		- overlay plane in the 1st channel (VI).
> > > > > 
> > > > > 	Note that there could be 3 overlay planes (a channel has 4
> > > > > 	layers), but I am not sure that the A83T or the H3 could
> > > > > 	support 3 simultaneous video streams...
> > > > 
> > > > Do you know if the pipe works in the old display engine?
> > > > 
> > > > Especially about the two-steps composition that wouldn't allow you to
> > > > have alpha on all the planes?
> > > > 
> > > > If it is similar, I think hardcoding the pipe number is pretty bad,
> > > > because that would restrict the combination of planes and formats,
> > > > while some other might have worked.
> > > 
> > > From what I understood about the DE2, the pipes just define the priority
> > > of the overlay channels (one pipe for one channel).
> > > With the cursor constraint, there must be at least 2 channels in
> > > order (primary, cursor). Then, with these 2 channels/pipes, there can be
> > > 6 so-called overlay planes (3 RGB/YUV and 3 RGB only).
> > > Enabling the pipes 2 and 3 (LCD 0 only) would offer 8 more planes, but
> > > RGB only. Then, it might be useful to have dynamic pipes.
> > 
> > That's very valuable (and definitely should go into a comment),
> > thanks!
> > 
> > I still believe that's it should be into a (simple at first)
> > atomic_check. That would be easier to extend and quite easy to
> > document and get simply by looking at the code.
> 
> Sorry for I don't understand what you mean.

You can check all the constraints you exposed above in atomic_check
instead of hardcoding it.

> > > > > > > +static int __init de2_drm_init(void)
> > > > > > > +{
> > > > > > > +	int ret;
> > > > > > > +
> > > > > > > +/* uncomment to activate the drm traces at startup time */
> > > > > > > +/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
> > > > > > > +			DRM_UT_PRIME | DRM_UT_ATOMIC; */
> > > > > > 
> > > > > > That's useless.
> > > > > 
> > > > > Right, but it seems that some people don't know how to debug a DRM
> > > > > driver. This is only a reminder.
> > > > > 
> > > > > > > +	DRM_DEBUG_DRIVER("\n");
> > > > > > > +
> > > > > > > +	ret = platform_driver_register(&de2_lcd_platform_driver);
> > > > > > > +	if (ret < 0)
> > > > > > > +		return ret;
> > > > > > > +
> > > > > > > +	ret = platform_driver_register(&de2_drm_platform_driver);
> > > > > > > +	if (ret < 0)
> > > > > > > +		platform_driver_unregister(&de2_lcd_platform_driver);
> > > > > > > +
> > > > > > > +	return ret;
> > > > > > > +}
> > > > > > 
> > > > > > And that really shouldn't be done that way.
> > > > > 
> > > > > May you explain?
> > > > 
> > > > This goes against the whole idea of the device and driver
> > > > model. Drivers should only register themselves, device should be
> > > > created by buses (or by using some external components if the bus
> > > > can't: DT, ACPI, etc.). If there's a match, you get probed.
> > > > 
> > > > A driver that creates its own device just to probe itself violates
> > > > that.
> > > 
> > > In this function (module init), there is no driver yet.
> > > The module contains 2 drivers: the DE (planes) and the LCD (CRTC),
> > > and there is no macro to handle such modules.
> > 
> > Ah, yes, my bad. I thought you were registering a device and a
> > driver. Still this is a very unusual pattern. Why do you need to split
> > the two? Can't you just merge them?
> 
> The DE and the LCDs are different devices on different drivers.
> A DE must be only one device because it has to handle concurent
> accesses from its 2 LCDs. Then 2 drivers.

If it's different drivers, why are they in the same module?

> But only one module. Why? Because there cannot be double direction
> calls from one module to an other one, and, in our case, for example,
> - the DRM (DE) device must call vblank functions which are handled in
>   the CRTC (TCON) device, and
> - the CRTC device must call DE initialization functions at startup time.

I'm sorry, but that doesn't make any sense. The crtc device should
take care of the CRTC functions. Your DRM CRTC and encoders can
definitely be shared across different devices, you can have a look at
how we're doing it for sun4i.

We basically have 3 drivers to create most of the display pipeline:
  - One for the DRM device
  - One for the display engine
  - One for the TCON

Once they have all loaded and registered in the component framework,
their bind callback is called, and it's when the DRM entities are
created using exported functions to manipulate what needs to be setup.

It's definitely doable, it just takes some effort.

> > > > > > > +int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
> > > > > > > +{
> > > > > > > +	int ret, possible_crtcs = 1 << lcd->crtc_idx;
> > > > > > > +
> > > > > > > +	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
> > > > > > > +				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
> > > > > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > > > > +	if (ret >= 0)
> > > > > > > +		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
> > > > > > > +				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
> > > > > > > +				ui_formats, ARRAY_SIZE(ui_formats));
> > > > > > 
> > > > > > Nothing looks really special about that cursor plane. Any reasion not
> > > > > > to make it an overlay?
> > > > > 
> > > > > As explained above (channel/layer/pipe plane definitions), the cursor
> > > > > cannot go in a channel lower or equal to the one of the primary plane.
> > > > > Then, it must be known and, so, have an explicit plane.
> > > > 
> > > > If you were to make it a plane, you could use atomic_check to check
> > > > this and make sure this doesn't happen. And you would gain a generic
> > > > plane that can be used for other purposes if needed.
> > > 
> > > The function drm_crtc_init_with_planes() offers a cursor plane for free.
> > > On the other side, having 6 overlay planes is more than the SoCs can
> > > support.
> > 
> > It's not really for free, it costs you a generic plane that could
> > definitely be used for something else and cannot anymore because
> > they've been hardcoded to a cursor.
> > 
> > And having a camera, the VPU or even an application directly output
> > directly into one of these planes seems a much better use of a generic
> > plane than a cursor.
> 
> Looking at the harder case (A83T), there may be 8 planes on 2 channels.
> Using a primary plane and the cursor,
> 	8 planes - primary plane - cursor plane = 6 planes
> 6 planes are available.
> If I count correctly, in your example:
> 	one camera + one VPU + one application = 3 planes
> 3 planes are used.
> So, 3 planes are still available.
> 
> On the other side, removing the cursor would just let one more plane.
> Do we really need this one? In other words, I'd be pleased to know how
> you run 7 applications doing video overlay.

You can use those planes to do composition too, with each application
having one or more plane. Android uses that.

There's no argument to have a cursor plane, really. Even regular
graphic stack like X can use a regular overlay to have its cursor on
it. It doesn't *remove* anything, it just allows to use the plane for
what it was supposed to be used for.

Maxime
Jean-Francois Moine Nov. 17, 2016, 2:57 p.m. UTC | #14
On Wed, 16 Nov 2016 22:33:06 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> > > > The Device Engine just handles the planes of the LCDs, but, indeed,
> > > > the LCDs must know about the DE and the DE must know about the LCDs.
> > > > There are 2 ways to realize this knowledge in the DT:
> > > > 1) either the DE has one or two phandle's to the LCDs,
> > > > 2) or the LCDs have a phandle to the DE.
> > > > 
> > > > I chose the 1st way, the DE ports pointing to the endpoint of the LCDs
> > > > which is part of the video link (OF-graph LCD <-> connector).
> > > > It would be possible to have phandles to the LCDs themselves, but this
> > > > asks for more code.
> > > > 
> > > > The second way is also possible, but it also complexifies a bit the
> > > > exchanges DE <-> LCD.
> > > 
> > > I'm still not sure how it would complexify anything, and why you can't
> > > use the display graph to model the relation between the display engine
> > > and the TCON (and why you want to use a generic property that refers
> > > to the of-graph while it really isn't).
> > 
> > Complexification:
> > 1- my solution:
> >   At startup time, the DE device is the DRM device.
> 
> How do you deal with SoCs with multiple display engines then?

In the H3, A83T and A64, there is only one DE.
If many DEs in a SoC, there may be either one DRM device per DE or one
DRM device for the whole system. In this last case, the (global) DE
would have many resources (many I/O memory maps / IRQs..) and the
physical DE of each endpoint would be indicated by the position of its
phandle in the 'ports' array (DT documentation).

> > It has to know the devices entering in the video chains.
> >   The CRTCs (LCD/TCON) are found by
> > 	ports[i] -> parent
> >   The connectors are found by
> > 	ports[i] -> endpoint -> remote_endpoint -> parent
> > 2- with ports pointing to the LCDs:
> >   The CRTCs (LCD/TCON) are simply
> > 	ports[i]
> >   The connectors are found by
> > 	loop on all ports of ports[i]
> > 		ports[i][j] -> endpoint -> remote_endpoint -> parent
> > 3- with a phandle to the DE in the LCDs:
> 
> What do you mean with LCD? Panels? Why would panels have a phandle to
> the display engine?

LCD is the same as CRTC. I don't think people will connect old CRT's to
their new ARM boards. LCD's may be panels, modern TV sets, or any
digital display. The word LCD seems clearer to me in this context, even
if there may a DAC as an ancoder.

> >   The DE cannot be the DRM device because there is no information about
> >   the video devices in the DT. Then, the DRM devices are the LCDs.
> >   These LCDs must give their indices to the DE. So, the DE must implement
> >   some callback function to accept a LCD definition, and there must be
> >   a list of DEs in the driver to make the association DE <-> LCD[i]
> >   Some more problem may be raised if a user wants to have the same frame
> >   buffer on the 2 LCDs of a DE.
> 
> I have no idea what you're talking about, sorry.

Here is the DT (I am using back 'CRTC'):

	de: display-controller@xxx {
		...
	};
	crtc0: crt-controller@xxx{
		...
		display-controller = <&de>;
		ports {
			...		/* to the crtc0 connectors */
		}
	};
	crtc1: crt-controller@xxx{
		...
		display-controller = <&de>;
		ports {
			...		/* to the crtc1 connectors */
		};
	};

There are 2 DRM devices: one on crtc0, the other one on crtc1.
The DE device is isolated. But, to treat the planes, it must receive
information about the CRTCs. How?

> > Anyway, my solution is already used in the IMX Soc.
> > See 'display-subsystem' in arch/arm/boot/dts/imx6q.dtsi for an example.
> 
> Pointing out random example in the tree doesn't make a compelling
> argument.

This is not a random example. There was a thread about the 'ports'
phandle in the DT definition of the IMX video subsystem, and what kind
of OF function should be used (see one of my previous mails). In the DRI
list, nobody objected about the phandle by itself.

> > > > > > > Panel functions? In the CRTC driver?
> > > > > > 
> > > > > > Yes, dumb panel.
> > > > > 
> > > > > What do you mean by that? Using a Parallel/RGB interface?
> > > > 
> > > > Sorry, I though this was a well-known name. The 'dump panel' was used
> > > > in the documentation of my previous ARM machine as the video frame sent
> > > > to the HDMI controller. 'video_frame' is OK for you?
> > > 
> > > If it's the frame sent to the encoder, then it would be the CRTC by
> > > DRM's nomenclature.
> > 
> > The CRTC is a software entity. The frame buffer is a hardware entity.
> 
> Why are you about framebuffer now, this is nowhere in that
> discussion. Any way, the framebuffer is also what is put in a plane,
> so there's a name collision here, and you'll probably want to change
> it.
> 
> Judging by the previous discussion, this should really be called
> encoder if it encodes the frames on a bus format, or CRTC if it
> composes the planes.

I think that we will end in agreeing on the words. We just need some
time!
Here is how I understand the Allwinner's DE2:

- the TCON is the piece of hardware which gets some memory area and
  sends it to a bus according to some configuation (screen resolution,
  timings...). The bus data are encoded and transmitted to the connector.
  At the end, the display device receives frames. So, going back to the
  TCON, the memory are is the frame buffer.

- this frame buffer is virtual, empty, 'dumb', it is a dumb panel!
  It is filled by planes. This job is done by a specific image
  processor, the one contained in the DE2.

- the DE2 processor gets the plane source images from the SoC memory.
  It adjusts the images according to many configuration parameters and
  includes the result into the frame buffer.

So:
	LCD = CRTC = frame buffer = dumb panel = TCON

- LCD = hardware piece of a display device (terminal side) which renders
  the colored pixels in a digital way. By extension, the hardware part
  (computer side) of a display engine which handles the definitions of
  a digital or analog physical display device. By extension also,
  the software structure (driver side) which defines a physical screen.

- CRTC = DRM software entity which handles the definitions of a screen,
  but not just a CRT.

- frame buffer = piece of memory which contains the images which are
  sent to a screen.

- dumb panel = abstract entity which defines the characteristics of a
  physical screen.

You may note that, in the DE2 scheme, the TCON and LCD are not in the
same (software) device while they are part of the same DRM software
entity, the CTRC.

> > > > > If it is similar, I think hardcoding the pipe number is pretty bad,
> > > > > because that would restrict the combination of planes and formats,
> > > > > while some other might have worked.
> > > > 
> > > > From what I understood about the DE2, the pipes just define the priority
> > > > of the overlay channels (one pipe for one channel).
> > > > With the cursor constraint, there must be at least 2 channels in
> > > > order (primary, cursor). Then, with these 2 channels/pipes, there can be
> > > > 6 so-called overlay planes (3 RGB/YUV and 3 RGB only).
> > > > Enabling the pipes 2 and 3 (LCD 0 only) would offer 8 more planes, but
> > > > RGB only. Then, it might be useful to have dynamic pipes.
> > > 
> > > That's very valuable (and definitely should go into a comment),
> > > thanks!
> > > 
> > > I still believe that's it should be into a (simple at first)
> > > atomic_check. That would be easier to extend and quite easy to
> > > document and get simply by looking at the code.
> > 
> > Sorry for I don't understand what you mean.
> 
> You can check all the constraints you exposed above in atomic_check
> instead of hardcoding it.

Sorry, but I don't like to run useless code for pure static definition.

> > The DE and the LCDs are different devices on different drivers.
> > A DE must be only one device because it has to handle concurent
> > accesses from its 2 LCDs. Then 2 drivers.
> 
> If it's different drivers, why are they in the same module?
> 
> > But only one module. Why? Because there cannot be double direction
> > calls from one module to an other one, and, in our case, for example,
> > - the DRM (DE) device must call vblank functions which are handled in
> >   the CRTC (TCON) device, and
> > - the CRTC device must call DE initialization functions at startup time.
> 
> I'm sorry, but that doesn't make any sense. The crtc device should
> take care of the CRTC functions. Your DRM CRTC and encoders can
> definitely be shared across different devices, you can have a look at
> how we're doing it for sun4i.
> 
> We basically have 3 drivers to create most of the display pipeline:
>   - One for the DRM device
>   - One for the display engine
>   - One for the TCON

Your DRM device is useless. It is simpler to have the DRM device as the
display engine.
Also, maybe, you have not the constraint the DE being shared between
2 CRTCs.

> Once they have all loaded and registered in the component framework,
> their bind callback is called, and it's when the DRM entities are
> created using exported functions to manipulate what needs to be setup.
> 
> It's definitely doable, it just takes some effort.

It seems you did not look at what I have coded...

> > On the other side, removing the cursor would just let one more plane.
> > Do we really need this one? In other words, I'd be pleased to know how
> > you run 7 applications doing video overlay.
> 
> You can use those planes to do composition too, with each application
> having one or more plane. Android uses that.
> 
> There's no argument to have a cursor plane, really. Even regular
> graphic stack like X can use a regular overlay to have its cursor on
> it. It doesn't *remove* anything, it just allows to use the plane for
> what it was supposed to be used for.

I'd be glad to know how you can have a hardware cursor without defining
it in drm_crtc_init_with_planes().
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
new file mode 100644
index 0000000..f9cd67a
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/sunxi/sunxi-de2.txt
@@ -0,0 +1,83 @@ 
+Allwinner sunxi Display Engine 2 subsystem
+==========================================
+
+The sunxi DE2 subsystem contains a display controller (DE2),
+one or two LCD controllers (TCON) and their external interfaces.
+
+Display controller
+==================
+
+Required properties:
+
+- compatible: value should be one of the following
+		"allwinner,sun8i-a83t-display-engine"
+		"allwinner,sun8i-h3-display-engine"
+
+- clocks: must include clock specifiers corresponding to entries in the
+		clock-names property.
+
+- clock-names: must contain
+		"gate": for DE activation
+		"clock": DE clock
+
+- resets: phandle to the reset of the device
+
+- ports: phandle's to the LCD ports
+
+LCD controller
+==============
+
+Required properties:
+
+- compatible: value should be one of the following
+		"allwinner,sun8i-a83t-lcd"
+
+- clocks: must include clock specifiers corresponding to entries in the
+		clock-names property.
+
+- clock-names: must contain
+		"gate": for LCD activation
+		"clock": pixel clock
+
+- resets: phandle to the reset of the device
+
+- port: port node with endpoint definitions as defined in
+	Documentation/devicetree/bindings/media/video-interfaces.txt
+
+Example:
+
+	de: de-controller@01000000 {
+		compatible = "allwinner,sun8i-h3-display-engine";
+		...
+		clocks = <&&ccu CLK_BUS_DE>, <&ccu CLK_DE>;
+		clock-names = "gate", "clock";
+		resets = <&ccu RST_BUS_DE>;
+		ports = <&lcd0_p>;
+	};
+
+	lcd0: lcd-controller@01c0c000 {
+		compatible = "allwinner,sun8i-a83t-lcd";
+		...
+		clocks = <&ccu CLK_BUS_TCON0>, <&ccu CLK_TCON0>;
+		clock-names = "gate", "clock";
+		resets = <&ccu RST_BUS_TCON0>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		lcd0_p: port {
+			lcd0_ep: endpoint {
+				remote-endpoint = <&hdmi_ep>;
+			};
+		};
+	};
+
+	hdmi: hdmi@01ee0000 {
+		...
+		#address-cells = <1>;
+		#size-cells = <0>;
+		port {
+			type = "video";
+			hdmi_ep: endpoint {
+				remote-endpoint = <&lcd0_ep>;
+			};
+		};
+	};
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 483059a..afd576f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -187,6 +187,8 @@  source "drivers/gpu/drm/shmobile/Kconfig"
 
 source "drivers/gpu/drm/sun4i/Kconfig"
 
+source "drivers/gpu/drm/sunxi/Kconfig"
+
 source "drivers/gpu/drm/omapdrm/Kconfig"
 
 source "drivers/gpu/drm/tilcdc/Kconfig"
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 25c7204..120d0bf 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -70,6 +70,7 @@  obj-$(CONFIG_DRM_RCAR_DU) += rcar-du/
 obj-$(CONFIG_DRM_SHMOBILE) +=shmobile/
 obj-y			+= omapdrm/
 obj-$(CONFIG_DRM_SUN4I) += sun4i/
+obj-$(CONFIG_DRM_SUNXI) += sunxi/
 obj-y			+= tilcdc/
 obj-$(CONFIG_DRM_QXL) += qxl/
 obj-$(CONFIG_DRM_BOCHS) += bochs/
diff --git a/drivers/gpu/drm/sunxi/Kconfig b/drivers/gpu/drm/sunxi/Kconfig
new file mode 100644
index 0000000..56bde2e
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/Kconfig
@@ -0,0 +1,21 @@ 
+#
+# Allwinner Video configuration
+#
+
+config DRM_SUNXI
+	tristate "DRM Support for Allwinner Video"
+	depends on DRM && OF
+	depends on ARCH_SUNXI || COMPILE_TEST
+	select DRM_KMS_HELPER
+	select DRM_KMS_CMA_HELPER
+	select DRM_GEM_CMA_HELPER
+	help
+	  Choose this option if you have a Allwinner chipset.
+
+config DRM_SUNXI_DE2
+	tristate "Support for Allwinner Video with DE2 interface"
+	depends on DRM_SUNXI
+	help
+	  Choose this option if your Allwinner chipset has the DE2 interface
+	  as the A64, A83T and H3. If M is selected the module will be called
+	  sunxi-de2-drm.
diff --git a/drivers/gpu/drm/sunxi/Makefile b/drivers/gpu/drm/sunxi/Makefile
new file mode 100644
index 0000000..62220cb
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/Makefile
@@ -0,0 +1,7 @@ 
+#
+# Makefile for Allwinner's sun8i DRM device driver
+#
+
+sunxi-de2-drm-objs := de2_drv.o de2_de.o de2_crtc.o de2_plane.o
+
+obj-$(CONFIG_DRM_SUNXI_DE2) += sunxi-de2-drm.o
diff --git a/drivers/gpu/drm/sunxi/de2_crtc.c b/drivers/gpu/drm/sunxi/de2_crtc.c
new file mode 100644
index 0000000..dae0fab
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/de2_crtc.c
@@ -0,0 +1,475 @@ 
+/*
+ * Allwinner DRM driver - DE2 CRTC
+ *
+ * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/component.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_atomic_helper.h>
+#include <asm/io.h>
+#include <linux/of_irq.h>
+
+#include "de2_drm.h"
+#include "de2_crtc.h"
+
+/* I/O map */
+
+struct tcon {
+	u32 gctl;
+#define		TCON_GCTL_TCON_En BIT(31)
+	u32 gint0;
+#define		TCON_GINT0_TCON1_Vb_Int_En BIT(30)
+#define		TCON_GINT0_TCON1_Vb_Int_Flag BIT(14)
+	u32 gint1;
+	u32 dum0[13];
+	u32 tcon0_ctl;				/* 0x40 */
+#define		TCON0_CTL_TCON_En BIT(31)
+	u32 dum1[19];
+	u32 tcon1_ctl;				/* 0x90 */
+#define		TCON1_CTL_TCON_En BIT(31)
+#define		TCON1_CTL_Interlace_En BIT(20)
+#define		TCON1_CTL_Start_Delay_SHIFT 4
+#define		TCON1_CTL_Start_Delay_MASK GENMASK(8, 4)
+	u32 basic0;			/* XI/YI */
+	u32 basic1;			/* LS_XO/LS_YO */
+	u32 basic2;			/* XO/YO */
+	u32 basic3;			/* HT/HBP */
+	u32 basic4;			/* VT/VBP */
+	u32 basic5;			/* HSPW/VSPW */
+	u32 dum2;
+	u32 ps_sync;				/* 0xb0 */
+	u32 dum3[15];
+	u32 io_pol;				/* 0xf0 */
+#define		TCON1_IO_POL_IO0_inv BIT(24)
+#define		TCON1_IO_POL_IO1_inv BIT(25)
+#define		TCON1_IO_POL_IO2_inv BIT(26)
+	u32 io_tri;
+	u32 dum4[2];
+
+	u32 ceu_ctl;				/* 0x100 */
+#define     TCON_CEU_CTL_ceu_en BIT(31)
+	u32 dum5[3];
+	u32 ceu_rr;
+	u32 ceu_rg;
+	u32 ceu_rb;
+	u32 ceu_rc;
+	u32 ceu_gr;
+	u32 ceu_gg;
+	u32 ceu_gb;
+	u32 ceu_gc;
+	u32 ceu_br;
+	u32 ceu_bg;
+	u32 ceu_bb;
+	u32 ceu_bc;
+	u32 ceu_rv;
+	u32 ceu_gv;
+	u32 ceu_bv;
+	u32 dum6[45];
+
+	u32 mux_ctl;				/* 0x200 */
+	u32 dum7[63];
+
+	u32 fill_ctl;				/* 0x300 */
+	u32 fill_start0;
+	u32 fill_end0;
+	u32 fill_data0;
+};
+
+#define XY(x, y) (((x) << 16) | (y))
+
+#define tcon_read(base, member) \
+	readl_relaxed(base + offsetof(struct tcon, member))
+#define tcon_write(base, member, data) \
+	writel_relaxed(data, base + offsetof(struct tcon, member))
+
+/* vertical blank functions */
+static void de2_atomic_flush(struct drm_crtc *crtc,
+			struct drm_crtc_state *old_state)
+{
+	struct drm_pending_vblank_event *event = crtc->state->event;
+
+	if (event) {
+		crtc->state->event = NULL;
+		spin_lock_irq(&crtc->dev->event_lock);
+		if (drm_crtc_vblank_get(crtc) == 0)
+			drm_crtc_arm_vblank_event(crtc, event);
+		else
+			drm_crtc_send_vblank_event(crtc, event);
+		spin_unlock_irq(&crtc->dev->event_lock);
+	}
+}
+
+static irqreturn_t de2_lcd_irq(int irq, void *dev_id)
+{
+	struct lcd *lcd = (struct lcd *) dev_id;
+	u32 isr;
+
+	isr = tcon_read(lcd->mmio, gint0);
+
+	drm_crtc_handle_vblank(&lcd->crtc);
+
+	tcon_write(lcd->mmio, gint0, isr & ~TCON_GINT0_TCON1_Vb_Int_Flag);
+
+	return IRQ_HANDLED;
+}
+
+int de2_enable_vblank(struct drm_device *drm, unsigned crtc)
+{
+	struct priv *priv = drm->dev_private;
+	struct lcd *lcd = priv->lcds[crtc];
+
+	tcon_write(lcd->mmio, gint0,
+			tcon_read(lcd->mmio, gint0) |
+					TCON_GINT0_TCON1_Vb_Int_En);
+	return 0;
+}
+
+void de2_disable_vblank(struct drm_device *drm, unsigned crtc)
+{
+	struct priv *priv = drm->dev_private;
+	struct lcd *lcd = priv->lcds[crtc];
+
+	tcon_write(lcd->mmio, gint0,
+			 tcon_read(lcd->mmio, gint0) &
+					~TCON_GINT0_TCON1_Vb_Int_En);
+}
+
+/* panel functions */
+static void de2_set_frame_timings(struct lcd *lcd)
+{
+	struct drm_crtc *crtc = &lcd->crtc;
+	const struct drm_display_mode *mode = &crtc->mode;
+	int interlace = mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 1;
+	int start_delay;
+	u32 data;
+
+	data = XY(mode->hdisplay - 1, mode->vdisplay / interlace - 1);
+	tcon_write(lcd->mmio, basic0, data);
+	tcon_write(lcd->mmio, basic1, data);
+	tcon_write(lcd->mmio, basic2, data);
+	tcon_write(lcd->mmio, basic3,
+			XY(mode->htotal - 1,
+				mode->htotal - mode->hsync_start - 1));
+	tcon_write(lcd->mmio, basic4,
+			XY(mode->vtotal * (3 - interlace),
+				mode->vtotal - mode->vsync_start - 1));
+	tcon_write(lcd->mmio, basic5,
+			 XY(mode->hsync_end - mode->hsync_start - 1,
+				mode->vsync_end - mode->vsync_start - 1));
+
+	tcon_write(lcd->mmio, ps_sync, XY(1, 1));
+
+	data = TCON1_IO_POL_IO2_inv;
+	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
+		data |= TCON1_IO_POL_IO0_inv;
+	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
+		data |= TCON1_IO_POL_IO1_inv;
+	tcon_write(lcd->mmio, io_pol, data);
+
+	tcon_write(lcd->mmio, ceu_ctl,
+		tcon_read(lcd->mmio, ceu_ctl) & ~TCON_CEU_CTL_ceu_en);
+
+	data = tcon_read(lcd->mmio, tcon1_ctl);
+	if (interlace == 2)
+		data |= TCON1_CTL_Interlace_En;
+	else
+		data &= ~TCON1_CTL_Interlace_En;
+	tcon_write(lcd->mmio, tcon1_ctl, data);
+
+	tcon_write(lcd->mmio, fill_ctl, 0);
+	tcon_write(lcd->mmio, fill_start0, mode->vtotal + 1);
+	tcon_write(lcd->mmio, fill_end0, mode->vtotal);
+	tcon_write(lcd->mmio, fill_data0, 0);
+
+	start_delay = (mode->vtotal - mode->vdisplay) / interlace - 5;
+	if (start_delay > 31)
+		start_delay = 31;
+	data = tcon_read(lcd->mmio, tcon1_ctl);
+	data &= ~TCON1_CTL_Start_Delay_MASK;
+	data |= start_delay << TCON1_CTL_Start_Delay_SHIFT;
+	tcon_write(lcd->mmio, tcon1_ctl, data);
+
+	tcon_write(lcd->mmio, io_tri, 0x0fffffff);
+}
+
+static void de2_crtc_enable(struct drm_crtc *crtc)
+{
+	struct lcd *lcd = crtc_to_lcd(crtc);
+	struct drm_display_mode *mode = &crtc->mode;
+
+	DRM_DEBUG_DRIVER("\n");
+
+	clk_set_rate(lcd->clk, mode->clock * 1000);
+
+	de2_set_frame_timings(lcd);
+
+	tcon_write(lcd->mmio, tcon1_ctl,
+		tcon_read(lcd->mmio, tcon1_ctl) | TCON1_CTL_TCON_En);
+
+	de2_de_panel_init(lcd->priv, lcd->num, mode);
+
+	drm_mode_debug_printmodeline(mode);
+}
+
+static void de2_crtc_disable(struct drm_crtc *crtc)
+{
+	struct lcd *lcd = crtc_to_lcd(crtc);
+	unsigned long flags;
+
+	DRM_DEBUG_DRIVER("\n");
+
+	tcon_write(lcd->mmio, tcon1_ctl,
+		tcon_read(lcd->mmio, tcon1_ctl) & ~TCON1_CTL_TCON_En);
+
+	if (crtc->state->event && !crtc->state->active) {
+		spin_lock_irqsave(&crtc->dev->event_lock, flags);
+		drm_crtc_send_vblank_event(crtc, crtc->state->event);
+		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
+		crtc->state->event = NULL;
+	}
+}
+
+static const struct drm_crtc_funcs de2_crtc_funcs = {
+	.destroy	= drm_crtc_cleanup,
+	.set_config	= drm_atomic_helper_set_config,
+	.page_flip	= drm_atomic_helper_page_flip,
+	.reset		= drm_atomic_helper_crtc_reset,
+	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+};
+
+static const struct drm_crtc_helper_funcs de2_crtc_helper_funcs = {
+	.atomic_flush	= de2_atomic_flush,
+	.enable		= de2_crtc_enable,
+	.disable	= de2_crtc_disable,
+};
+
+static void de2_tcon_init(struct lcd *lcd)
+{
+	tcon_write(lcd->mmio, tcon0_ctl,
+		tcon_read(lcd->mmio, tcon0_ctl) & ~TCON0_CTL_TCON_En);
+	tcon_write(lcd->mmio, tcon1_ctl,
+		tcon_read(lcd->mmio, tcon1_ctl) & ~TCON1_CTL_TCON_En);
+	tcon_write(lcd->mmio, gctl,
+		tcon_read(lcd->mmio, gctl) & ~TCON_GCTL_TCON_En);
+
+	/* disable/ack interrupts */
+	tcon_write(lcd->mmio, gint0, 0);
+}
+
+static void de2_tcon_enable(struct lcd *lcd)
+{
+	tcon_write(lcd->mmio, gctl,
+		tcon_read(lcd->mmio, gctl) | TCON_GCTL_TCON_En);
+}
+
+static int de2_crtc_init(struct drm_device *drm, struct lcd *lcd)
+{
+	struct drm_crtc *crtc = &lcd->crtc;
+	int ret;
+
+	ret = de2_plane_init(drm, lcd);
+	if (ret < 0)
+		return ret;
+
+	drm_crtc_helper_add(crtc, &de2_crtc_helper_funcs);
+
+	ret = drm_crtc_init_with_planes(drm, crtc,
+					&lcd->planes[DE2_PRIMARY_PLANE],
+					&lcd->planes[DE2_CURSOR_PLANE],
+					&de2_crtc_funcs, NULL);
+	if (ret < 0)
+		return ret;
+
+	de2_tcon_enable(lcd);
+
+	de2_de_enable(lcd->priv, lcd->num);
+
+	return 0;
+}
+
+/*
+ * device init
+ */
+static int de2_lcd_bind(struct device *dev, struct device *master,
+			void *data)
+{
+	struct drm_device *drm = data;
+	struct priv *priv = drm->dev_private;
+	struct lcd *lcd = dev_get_drvdata(dev);
+	int ret;
+
+	lcd->priv = priv;
+
+	/* (only 2 LCDs) */
+	lcd->crtc_idx = priv->lcds[0] ? 1 : 0;
+	priv->lcds[lcd->crtc_idx] = lcd;
+
+	ret = de2_crtc_init(drm, lcd);
+	if (ret < 0) {
+		dev_err(dev, "failed to init the crtc\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void de2_lcd_unbind(struct device *dev, struct device *master,
+			void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct lcd *lcd = platform_get_drvdata(pdev);
+
+	if (lcd->mmio) {
+		if (lcd->priv)
+			de2_de_disable(lcd->priv, lcd->num);
+		tcon_write(lcd->mmio, gctl,
+			tcon_read(lcd->mmio, gctl) & ~TCON_GCTL_TCON_En);
+	}
+}
+
+static const struct component_ops de2_lcd_ops = {
+	.bind = de2_lcd_bind,
+	.unbind = de2_lcd_unbind,
+};
+
+static int de2_lcd_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node, *tmp, *parent, *port;
+	struct lcd *lcd;
+	struct resource *res;
+	int id, irq, ret;
+
+	id = of_alias_get_id(np, "lcd");
+	if (id < 0) {
+		dev_err(dev, "no alias for lcd\n");
+		id = 0;
+	}
+	lcd = devm_kzalloc(dev, sizeof *lcd, GFP_KERNEL);
+	if (!lcd) {
+		dev_err(dev, "failed to allocate private data\n");
+		return -ENOMEM;
+	}
+	dev_set_drvdata(dev, lcd);
+	lcd->dev = dev;
+	lcd->num = id;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "failed to get memory resource\n");
+		return -EINVAL;
+	}
+
+	lcd->mmio = devm_ioremap_resource(dev, res);
+	if (IS_ERR(lcd->mmio)) {
+		dev_err(dev, "failed to map registers\n");
+		return PTR_ERR(lcd->mmio);
+	}
+
+	snprintf(lcd->name, sizeof(lcd->name), "sunxi-lcd%d", id);
+
+	/* possible CRTCs */
+	parent = np;
+	tmp = of_get_child_by_name(np, "ports");
+	if (tmp)
+		parent = tmp;
+	port = of_get_child_by_name(parent, "port");
+	of_node_put(tmp);
+	if (!port) {
+		dev_err(dev, "no port node\n");
+		return -ENXIO;
+	}
+	lcd->crtc.port = port;
+
+	lcd->gate = devm_clk_get(dev, "gate");		/* optional */
+
+	lcd->clk = devm_clk_get(dev, "clock");
+	if (IS_ERR(lcd->clk)) {
+		dev_err(dev, "video clock err %d\n", (int) PTR_ERR(lcd->clk));
+		ret = PTR_ERR(lcd->clk);
+		goto err;
+	}
+
+	lcd->rstc = devm_reset_control_get_optional(dev, NULL);
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq <= 0 || irq == NO_IRQ) {
+		dev_err(dev, "unable to get irq lcd %d\n", id);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (!IS_ERR(lcd->rstc)) {
+		ret = reset_control_deassert(lcd->rstc);
+		if (ret) {
+			dev_err(dev, "reset deassert err %d\n", ret);
+			goto err;
+		}
+	}
+
+	if (!IS_ERR(lcd->gate)) {
+		ret = clk_prepare_enable(lcd->gate);
+		if (ret)
+			goto err2;
+	}
+
+	ret = clk_prepare_enable(lcd->clk);
+	if (ret)
+		goto err2;
+
+	de2_tcon_init(lcd);
+
+	ret = devm_request_irq(dev, irq, de2_lcd_irq, 0,
+				lcd->name, lcd);
+	if (ret < 0) {
+		dev_err(dev, "unable to request irq %d\n", irq);
+		goto err2;
+	}
+
+	return component_add(dev, &de2_lcd_ops);
+
+err2:
+	if (!IS_ERR_OR_NULL(lcd->rstc))
+		reset_control_assert(lcd->rstc);
+	clk_disable_unprepare(lcd->gate);
+	clk_disable_unprepare(lcd->clk);
+err:
+	of_node_put(lcd->crtc.port);
+	return ret;
+}
+
+static int de2_lcd_remove(struct platform_device *pdev)
+{
+	struct lcd *lcd = platform_get_drvdata(pdev);
+
+	component_del(&pdev->dev, &de2_lcd_ops);
+
+	if (!IS_ERR_OR_NULL(lcd->rstc))
+		reset_control_assert(lcd->rstc);
+	clk_disable_unprepare(lcd->gate);
+	clk_disable_unprepare(lcd->clk);
+	of_node_put(lcd->crtc.port);
+
+	return 0;
+}
+
+static const struct of_device_id de2_lcd_ids[] = {
+	{ .compatible = "allwinner,sun8i-a83t-lcd", },
+	{ }
+};
+
+struct platform_driver de2_lcd_platform_driver = {
+	.probe = de2_lcd_probe,
+	.remove = de2_lcd_remove,
+	.driver = {
+		.name = "sunxi-de2-lcd",
+		.of_match_table = of_match_ptr(de2_lcd_ids),
+	},
+};
diff --git a/drivers/gpu/drm/sunxi/de2_crtc.h b/drivers/gpu/drm/sunxi/de2_crtc.h
new file mode 100644
index 0000000..efbe45d
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/de2_crtc.h
@@ -0,0 +1,63 @@ 
+#ifndef __DE2_CRTC_H__
+#define __DE2_CRTC_H__
+/*
+ * Copyright (C) 2016 Jean-François Moine
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <drm/drm_plane_helper.h>
+
+struct priv;
+
+enum de2_plane2 {
+	DE2_PRIMARY_PLANE,
+	DE2_CURSOR_PLANE,
+	DE2_VI_PLANE,
+	DE2_N_PLANES,
+};
+struct lcd {
+	void __iomem *mmio;
+
+	struct device *dev;
+	struct drm_crtc crtc;
+	struct priv *priv;	/* DRM/DE private data */
+
+	short num;		/* LCD number in hardware */
+	short crtc_idx;		/* CRTC index in drm */
+
+	struct clk *clk;
+	struct clk *gate;
+	struct reset_control *rstc;
+
+	char name[16];
+
+	struct drm_pending_vblank_event *event;
+
+	struct drm_plane planes[DE2_N_PLANES];
+};
+
+#define crtc_to_lcd(x) container_of(x, struct lcd, crtc)
+
+/* in de2_de.c */
+void de2_de_enable(struct priv *priv, int lcd_num);
+void de2_de_disable(struct priv *priv, int lcd_num);
+void de2_de_hw_init(struct priv *priv, int lcd_num);
+void de2_de_panel_init(struct priv *priv, int lcd_num,
+			struct drm_display_mode *mode);
+void de2_de_plane_disable(struct priv *priv,
+			int lcd_num, int plane_ix);
+void de2_de_plane_update(struct priv *priv,
+			int lcd_num, int plane_ix,
+			struct drm_plane_state *state,
+			struct drm_plane_state *old_state);
+
+/* in de2_plane.c */
+int de2_plane_init(struct drm_device *drm, struct lcd *lcd);
+
+#endif /* __DE2_CRTC_H__ */
diff --git a/drivers/gpu/drm/sunxi/de2_de.c b/drivers/gpu/drm/sunxi/de2_de.c
new file mode 100644
index 0000000..0d8cb62
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/de2_de.c
@@ -0,0 +1,591 @@ 
+/*
+ * ALLWINNER DRM driver - Display Engine 2
+ *
+ * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
+ * Copyright (c) 2016 Allwinnertech Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <asm/io.h>
+#include <drm/drm_gem_cma_helper.h>
+
+#include "de2_drm.h"
+#include "de2_crtc.h"
+
+static DEFINE_SPINLOCK(de_lock);
+
+#define DE_CLK_RATE_A83T 504000000	/* pll-de */
+#define DE_CLK_RATE_H3 432000000	/* de */
+
+/* I/O map */
+
+#define DE_MOD_REG 0x0000	/* 1 bit per LCD */
+#define DE_GATE_REG 0x0004
+#define DE_RESET_REG 0x0008
+#define DE_DIV_REG 0x000c	/* 4 bits per LCD */
+#define DE_SEL_REG 0x0010
+
+#define DE_MUX0_BASE 0x00100000
+#define DE_MUX1_BASE 0x00200000
+
+/* MUX registers (addr / MUX base) */
+#define DE_MUX_GLB_REGS 0x00000		/* global control */
+#define DE_MUX_BLD_REGS 0x01000		/* alpha blending */
+#define DE_MUX_CHAN_REGS 0x02000	/* VI/UI overlay channels */
+#define		DE_MUX_CHAN_SZ 0x1000	/* size of a channel */
+#define DE_MUX_VSU_REGS 0x20000		/* VSU */
+#define DE_MUX_GSU1_REGS 0x30000	/* GSUs */
+#define DE_MUX_GSU2_REGS 0x40000
+#define DE_MUX_GSU3_REGS 0x50000
+#define DE_MUX_FCE_REGS 0xa0000		/* FCE */
+#define DE_MUX_BWS_REGS 0xa2000		/* BWS */
+#define DE_MUX_LTI_REGS 0xa4000		/* LTI */
+#define DE_MUX_PEAK_REGS 0xa6000	/* PEAK */
+#define DE_MUX_ASE_REGS 0xa8000		/* ASE */
+#define DE_MUX_FCC_REGS 0xaa000		/* FCC */
+#define DE_MUX_DCSC_REGS 0xb0000	/* DCSC/SMBL */
+
+/* global control */
+struct de_glb {
+	u32 ctl;
+#define		DE_MUX_GLB_CTL_rt_en BIT(0)
+#define		DE_MUX_GLB_CTL_finish_irq_en BIT(4)
+#define		DE_MUX_GLB_CTL_rtwb_port BIT(12)
+	u32 status;
+	u32 dbuff;
+	u32 size;
+};
+
+/* alpha blending */
+struct de_bld {
+	u32 fcolor_ctl;			/* 00 */
+	struct {
+		u32 fcolor;
+		u32 insize;
+		u32 offset;
+		u32 dum;
+	} attr[4];
+	u32 dum0[15];			/* (end of clear offset) */
+	u32 route;			/* 80 */
+	u32 premultiply;
+	u32 bkcolor;
+	u32 output_size;
+	u32 bld_mode[4];
+	u32 dum1[4];
+	u32 ck_ctl;			/* b0 */
+	u32 ck_cfg;
+	u32 dum2[2];
+	u32 ck_max[4];			/* c0 */
+	u32 dum3[4];
+	u32 ck_min[4];			/* e0 */
+	u32 dum4[3];
+	u32 out_ctl;			/* fc */
+};
+
+/* VI channel */
+struct de_vi {
+	struct {
+		u32 attr;
+#define			VI_CFG_ATTR_en BIT(0)
+#define			VI_CFG_ATTR_fcolor_en BIT(4)
+#define			VI_CFG_ATTR_fmt_SHIFT 8
+#define			VI_CFG_ATTR_fmt_MASK GENMASK(12, 8)
+#define			VI_CFG_ATTR_ui_sel BIT(15)
+#define			VI_CFG_ATTR_top_down BIT(23)
+		u32 size;
+		u32 coord;
+#define VI_N_PLANES 3
+		u32 pitch[VI_N_PLANES];
+		u32 top_laddr[VI_N_PLANES];
+		u32 bot_laddr[VI_N_PLANES];
+	} cfg[4];
+	u32 fcolor[4];			/* c0 */
+	u32 top_haddr[VI_N_PLANES];	/* d0 */
+	u32 bot_haddr[VI_N_PLANES];	/* dc */
+	u32 ovl_size[2];		/* e8 */
+	u32 hori[2];			/* f0 */
+	u32 vert[2];			/* f8 */
+};
+
+/* UI channel */
+struct de_ui {
+	struct {
+		u32 attr;
+#define			UI_CFG_ATTR_en BIT(0)
+#define			UI_CFG_ATTR_alpmod_SHIFT 1
+#define			UI_CFG_ATTR_alpmod_MASK GENMASK(2, 1)
+#define			UI_CFG_ATTR_fcolor_en BIT(4)
+#define			UI_CFG_ATTR_fmt_SHIFT 8
+#define			UI_CFG_ATTR_fmt_MASK GENMASK(12, 8)
+#define			UI_CFG_ATTR_top_down BIT(23)
+#define			UI_CFG_ATTR_alpha_SHIFT 24
+#define			UI_CFG_ATTR_alpha_MASK GENMASK(31, 24)
+		u32 size;
+		u32 coord;
+		u32 pitch;
+		u32 top_laddr;
+		u32 bot_laddr;
+		u32 fcolor;
+		u32 dum;
+	} cfg[4];			/* 00 */
+	u32 top_haddr;			/* 80 */
+	u32 bot_haddr;
+	u32 ovl_size;			/* 88 */
+};
+
+/* coordinates and sizes */
+#define XY(x, y) (((y) << 16) | (x))
+#define WH(w, h) (((h - 1) << 16) | (w - 1))
+
+/* UI video formats */
+#define DE2_FORMAT_ARGB_8888 0
+#define DE2_FORMAT_BGRA_8888 3
+#define DE2_FORMAT_XRGB_8888 4
+#define DE2_FORMAT_RGB_888 8
+#define DE2_FORMAT_BGR_888 9
+
+/* VI video formats */
+#define DE2_FORMAT_YUV422_I_YVYU 1	/* Y-V-Y-U */
+#define DE2_FORMAT_YUV422_I_UYVY 2	/* U-Y-V-Y */
+#define DE2_FORMAT_YUV422_I_YUYV 3	/* Y-U-Y-V */
+#define DE2_FORMAT_YUV422_P 6		/* YYYY UU VV planar */
+#define DE2_FORMAT_YUV420_P 10		/* YYYY U V planar */
+
+#define glb_read(base, member) \
+	readl_relaxed(base + offsetof(struct de_glb, member))
+#define glb_write(base, member, data) \
+	writel_relaxed(data, base + offsetof(struct de_glb, member))
+#define bld_read(base, member) \
+	readl_relaxed(base + offsetof(struct de_bld, member))
+#define bld_write(base, member, data) \
+	writel_relaxed(data, base + offsetof(struct de_bld, member))
+#define ui_read(base, member) \
+	readl_relaxed(base + offsetof(struct de_ui, member))
+#define ui_write(base, member, data) \
+	writel_relaxed(data, base + offsetof(struct de_ui, member))
+#define vi_read(base, member) \
+	readl_relaxed(base + offsetof(struct de_vi, member))
+#define vi_write(base, member, data) \
+	writel_relaxed(data, base + offsetof(struct de_vi, member))
+
+static const struct {
+	char chan;
+	char layer;
+	char pipe;
+} plane2layer[DE2_N_PLANES] = {
+	[DE2_PRIMARY_PLANE] =	{0, 0, 0},
+	[DE2_CURSOR_PLANE] =	{1, 0, 1},
+	[DE2_VI_PLANE] =	{0, 1, 0},
+};
+
+static inline void de_write(struct priv *priv, int reg, u32 data)
+{
+	writel_relaxed(data, priv->mmio + reg);
+}
+
+static inline u32 de_read(struct priv *priv, int reg)
+{
+	return readl_relaxed(priv->mmio + reg);
+}
+
+static void de_lcd_select(struct priv *priv,
+			int lcd_num,
+			void __iomem *mux_o)
+{
+	u32 data;
+
+	/* select the LCD */
+	data = de_read(priv, DE_SEL_REG);
+	data &= ~1;
+	de_write(priv, DE_SEL_REG, data);
+
+	/* double register switch */
+	glb_write(mux_o + DE_MUX_GLB_REGS, dbuff, 1);
+}
+
+void de2_de_plane_update(struct priv *priv,
+			int lcd_num, int plane_ix,
+			struct drm_plane_state *state,
+			struct drm_plane_state *old_state)
+{
+	struct drm_framebuffer *fb = state->fb;
+	struct drm_gem_cma_object *gem;
+	void __iomem *mux_o = priv->mmio;
+	void __iomem *chan_o;
+	u32 size = WH(state->crtc_w, state->crtc_h);
+	u32 coord;
+	u32 screen_size;
+	u32 data, fcolor;
+	u32 ui_sel, alpha_glob;
+	int chan, layer, x, y;
+	unsigned fmt;
+	unsigned long flags;
+
+	chan = plane2layer[plane_ix].chan;
+	layer = plane2layer[plane_ix].layer;
+
+	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
+	chan_o = mux_o;
+	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
+
+	x = state->crtc_x >= 0 ? state->crtc_x : 0;
+	y = state->crtc_y >= 0 ? state->crtc_y : 0;
+	coord = XY(x, y);
+
+	/* handle the cursor move */
+	if (plane_ix == DE2_CURSOR_PLANE
+	 && fb == old_state->fb) {
+		spin_lock_irqsave(&de_lock, flags);
+		de_lcd_select(priv, lcd_num, mux_o);
+		if (chan == 0)
+			vi_write(chan_o, cfg[layer].coord, coord);
+		else
+			ui_write(chan_o, cfg[layer].coord, coord);
+		spin_unlock_irqrestore(&de_lock, flags);
+		return;
+	}
+
+	gem = drm_fb_cma_get_gem_obj(fb, 0);
+
+	ui_sel = alpha_glob = 0;
+	switch (fb->pixel_format) {
+	case DRM_FORMAT_ARGB8888:
+		fmt = DE2_FORMAT_ARGB_8888;
+		ui_sel = VI_CFG_ATTR_ui_sel;
+		break;
+	case DRM_FORMAT_BGRA8888:
+		fmt = DE2_FORMAT_BGRA_8888;
+		ui_sel = VI_CFG_ATTR_ui_sel;
+		break;
+	case DRM_FORMAT_XRGB8888:
+		fmt = DE2_FORMAT_XRGB_8888;
+		ui_sel = VI_CFG_ATTR_ui_sel;
+		alpha_glob = (1 << UI_CFG_ATTR_alpmod_SHIFT) |
+				(0xff << UI_CFG_ATTR_alpha_SHIFT);
+		break;
+	case DRM_FORMAT_RGB888:
+		fmt = DE2_FORMAT_RGB_888;
+		ui_sel = VI_CFG_ATTR_ui_sel;
+		break;
+	case DRM_FORMAT_BGR888:
+		fmt = DE2_FORMAT_BGR_888;
+		ui_sel = VI_CFG_ATTR_ui_sel;
+		break;
+	case DRM_FORMAT_YUYV:
+		fmt = DE2_FORMAT_YUV422_I_YUYV;
+		break;
+	case DRM_FORMAT_YVYU:
+		fmt = DE2_FORMAT_YUV422_I_YVYU;
+		break;
+	case DRM_FORMAT_YUV422:
+		fmt = DE2_FORMAT_YUV422_P;
+		break;
+	case DRM_FORMAT_YUV420:
+		fmt = DE2_FORMAT_YUV420_P;
+		break;
+	case DRM_FORMAT_UYVY:
+		fmt = DE2_FORMAT_YUV422_I_UYVY;
+		break;
+	default:
+		pr_err("format %.4s not yet treated\n",
+			(char *) &fb->pixel_format);
+		return;
+	}
+
+	spin_lock_irqsave(&de_lock, flags);
+
+	screen_size = plane_ix == DE2_PRIMARY_PLANE ?
+			size :
+			glb_read(mux_o + DE_MUX_GLB_REGS, size);
+
+	/* prepare the activation of alpha blending (1 bit per plane) */
+	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl)
+			| (0x100 << plane2layer[plane_ix].pipe);
+
+	de_lcd_select(priv, lcd_num, mux_o);
+
+	if (chan == 0) {	/* VI channel */
+		int i;
+
+		data = VI_CFG_ATTR_en | (fmt << VI_CFG_ATTR_fmt_SHIFT) |
+					ui_sel;
+		vi_write(chan_o, cfg[layer].attr, data);
+		vi_write(chan_o, cfg[layer].size, size);
+		vi_write(chan_o, cfg[layer].coord, coord);
+		for (i = 0; i < VI_N_PLANES; i++) {
+			vi_write(chan_o, cfg[layer].pitch[i],
+					fb->pitches[i] ? fb->pitches[i] :
+							fb->pitches[0]);
+			vi_write(chan_o, cfg[layer].top_laddr[i],
+				gem->paddr + fb->offsets[i]);
+			vi_write(chan_o, fcolor[layer], 0xff000000);
+		}
+		if (layer == 0)
+			vi_write(chan_o, ovl_size[0], screen_size);
+
+	} else {		/* UI channel */
+		data = UI_CFG_ATTR_en | (fmt << UI_CFG_ATTR_fmt_SHIFT) |
+			alpha_glob;
+		ui_write(chan_o, cfg[layer].attr, data);
+		ui_write(chan_o, cfg[layer].size, size);
+		ui_write(chan_o, cfg[layer].coord, coord);
+		ui_write(chan_o, cfg[layer].pitch, fb->pitches[0]);
+		ui_write(chan_o, cfg[layer].top_laddr,
+				gem->paddr + fb->offsets[0]);
+		if (layer == 0)
+			ui_write(chan_o, ovl_size, screen_size);
+	}
+	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, fcolor);
+
+	spin_unlock_irqrestore(&de_lock, flags);
+}
+
+void de2_de_plane_disable(struct priv *priv,
+			int lcd_num, int plane_ix)
+{
+	void __iomem *mux_o = priv->mmio;
+	void __iomem *chan_o;
+	u32 fcolor;
+	int chan, layer, chan_disable = 0;
+	unsigned long flags;
+
+	chan = plane2layer[plane_ix].chan;
+	layer = plane2layer[plane_ix].layer;
+
+	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
+	chan_o = mux_o;
+	chan_o += DE_MUX_CHAN_REGS + DE_MUX_CHAN_SZ * chan;
+
+	/* (only 2 layers) */
+	if (chan == 0) {
+		if (vi_read(chan_o, cfg[1 - layer].attr) == 0)
+			chan_disable = 1;
+	} else {
+		if (ui_read(chan_o, cfg[1 - layer].attr) == 0)
+			chan_disable = 1;
+	}
+
+	spin_lock_irqsave(&de_lock, flags);
+
+	fcolor = bld_read(mux_o + DE_MUX_BLD_REGS, fcolor_ctl);
+
+	de_lcd_select(priv, lcd_num, mux_o);
+
+	if (chan == 0)
+		vi_write(chan_o, cfg[layer].attr, 0);
+	else
+		ui_write(chan_o, cfg[layer].attr, 0);
+
+	if (chan_disable)
+		bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl,
+			fcolor & ~(0x100 << plane2layer[plane_ix].pipe));
+
+	spin_unlock_irqrestore(&de_lock, flags);
+}
+
+void de2_de_panel_init(struct priv *priv, int lcd_num,
+			struct drm_display_mode *mode)
+{
+	void __iomem *mux_o = priv->mmio;
+	u32 size = WH(mode->hdisplay, mode->vdisplay);
+	unsigned i;
+	unsigned long flags;
+
+	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
+
+	DRM_DEBUG_DRIVER("%dx%d\n", mode->hdisplay, mode->vdisplay);
+
+	spin_lock_irqsave(&de_lock, flags);
+
+	de_lcd_select(priv, lcd_num, mux_o);
+
+	glb_write(mux_o + DE_MUX_GLB_REGS, size, size);
+
+	/* set alpha blending */
+	for (i = 0; i < 4; i++) {
+		bld_write(mux_o + DE_MUX_BLD_REGS, attr[i].fcolor, 0xff000000);
+		bld_write(mux_o + DE_MUX_BLD_REGS, attr[i].insize, size);
+	}
+	bld_write(mux_o + DE_MUX_BLD_REGS, output_size, size);
+	bld_write(mux_o + DE_MUX_BLD_REGS, out_ctl,
+			mode->flags & DRM_MODE_FLAG_INTERLACE ? 2 : 0);
+
+	spin_unlock_irqrestore(&de_lock, flags);
+}
+
+void de2_de_enable(struct priv *priv, int lcd_num)
+{
+	void __iomem *mux_o = priv->mmio;
+	unsigned chan, i;
+	u32 size = WH(1920, 1080);
+	u32 data;
+	unsigned long flags;
+
+	DRM_DEBUG_DRIVER("lcd %d\n", lcd_num);
+
+	de_write(priv, DE_RESET_REG,
+			de_read(priv, DE_RESET_REG) |
+				(lcd_num == 0 ? 1 : 4));
+	data = 1 << lcd_num;			/* 1 bit / lcd */
+	de_write(priv, DE_GATE_REG,
+			de_read(priv, DE_GATE_REG) | data);
+	de_write(priv, DE_MOD_REG,
+			de_read(priv, DE_MOD_REG) | data);
+
+	mux_o += (lcd_num == 0) ? DE_MUX0_BASE : DE_MUX1_BASE;
+
+	spin_lock_irqsave(&de_lock, flags);
+
+	/* select the LCD */
+	data = de_read(priv, DE_SEL_REG);
+	if (lcd_num == 0)
+		data &= ~1;
+	else
+		data |= 1;
+	de_write(priv, DE_SEL_REG, data);
+
+	/* start init */
+	glb_write(mux_o + DE_MUX_GLB_REGS, ctl,
+		DE_MUX_GLB_CTL_rt_en | DE_MUX_GLB_CTL_rtwb_port);
+	glb_write(mux_o + DE_MUX_GLB_REGS, status, 0);
+	glb_write(mux_o + DE_MUX_GLB_REGS, dbuff, 1);	/* dble reg switch */
+	glb_write(mux_o + DE_MUX_GLB_REGS, size, size);
+
+	/* clear the VI/UI channels */
+	for (chan = 0; chan < 4; chan++) {
+		void __iomem *chan_o = mux_o + DE_MUX_CHAN_REGS +
+				DE_MUX_CHAN_SZ * chan;
+
+		memset_io(chan_o, 0, chan == 0 ?
+				sizeof(struct de_vi) : sizeof(struct de_ui));
+
+		/* only 1 VI and 1 UI in lcd1 */
+		if (chan == 2 && lcd_num == 1)
+			break;
+	}
+
+	/* clear and set alpha blending */
+	memset_io(mux_o + DE_MUX_BLD_REGS, 0, offsetof(struct de_bld, dum0));
+	bld_write(mux_o + DE_MUX_BLD_REGS, fcolor_ctl, 0x00000101);
+						/* fcolor for primary */
+
+	/* prepare route for planes */
+	data = 0;
+	for (i = 0; i < DE2_N_PLANES; i++)
+		data |= plane2layer[i].chan << (plane2layer[i].pipe * 4);
+	bld_write(mux_o + DE_MUX_BLD_REGS, route, data);
+
+	bld_write(mux_o + DE_MUX_BLD_REGS, premultiply, 0);
+	bld_write(mux_o + DE_MUX_BLD_REGS, bkcolor, 0xff000000);
+	bld_write(mux_o + DE_MUX_BLD_REGS, bld_mode[0], 0x03010301);
+								/* SRCOVER */
+	bld_write(mux_o + DE_MUX_BLD_REGS, bld_mode[1], 0x03010301);
+	bld_write(mux_o + DE_MUX_BLD_REGS, out_ctl, 0);
+
+	/* disable the enhancements */
+	writel_relaxed(0, mux_o + DE_MUX_VSU_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_GSU1_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_GSU2_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_GSU3_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_FCE_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_BWS_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_LTI_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_PEAK_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_ASE_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_FCC_REGS);
+	writel_relaxed(0, mux_o + DE_MUX_DCSC_REGS);
+
+	spin_unlock_irqrestore(&de_lock, flags);
+}
+
+void de2_de_disable(struct priv *priv, int lcd_num)
+{
+	u32 data;
+
+	data = ~(1 << lcd_num);
+	de_write(priv, DE_MOD_REG,
+			de_read(priv, DE_MOD_REG) & data);
+	de_write(priv, DE_GATE_REG,
+			de_read(priv, DE_GATE_REG) & data);
+	de_write(priv, DE_RESET_REG,
+			de_read(priv, DE_RESET_REG) & data);
+}
+
+int de2_de_init(struct priv *priv, struct device *dev)
+{
+	struct resource *res;
+	int ret;
+
+	DRM_DEBUG_DRIVER("\n");
+
+	res = platform_get_resource(to_platform_device(dev),
+				IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "failed to get memory resource\n");
+		return -EINVAL;
+	}
+
+	priv->mmio = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->mmio)) {
+		dev_err(dev, "failed to map registers\n");
+		return PTR_ERR(priv->mmio);
+	}
+
+	priv->gate = devm_clk_get(dev, "gate");	/* optional */
+
+	priv->clk = devm_clk_get(dev, "clock");
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "video clock err %d\n", (int) PTR_ERR(priv->clk));
+		return PTR_ERR(priv->clk);
+	}
+
+	priv->rstc = devm_reset_control_get_optional(dev, NULL);
+
+	if (!IS_ERR(priv->rstc)) {
+		ret = reset_control_deassert(priv->rstc);
+		if (ret) {
+			dev_err(dev, "reset deassert err %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (!IS_ERR(priv->gate)) {
+		ret = clk_prepare_enable(priv->gate);
+		if (ret)
+			goto err_gate;
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		goto err_enable;
+	if (priv->soc_type == SOC_A83T)
+		clk_set_rate(priv->clk, DE_CLK_RATE_A83T);
+	else
+		clk_set_rate(priv->clk, DE_CLK_RATE_H3);
+
+	/* set the A83T clock divider = 500 / 250 */
+	if (priv->soc_type == SOC_A83T)
+		de_write(priv, DE_DIV_REG,
+				0x00000011);	/* div = 2 for both LCDs */
+
+	return 0;
+
+err_enable:
+	clk_disable_unprepare(priv->gate);
+err_gate:
+	if (!IS_ERR(priv->rstc))
+		reset_control_assert(priv->rstc);
+	return ret;
+}
+
+void de2_de_cleanup(struct priv *priv)
+{
+	clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->gate);
+	if (!IS_ERR(priv->rstc))
+		reset_control_assert(priv->rstc);
+}
diff --git a/drivers/gpu/drm/sunxi/de2_drm.h b/drivers/gpu/drm/sunxi/de2_drm.h
new file mode 100644
index 0000000..7bb966c
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/de2_drm.h
@@ -0,0 +1,47 @@ 
+#ifndef __DE2_DRM_H__
+#define __DE2_DRM_H__
+/*
+ * Copyright (C) 2016 Jean-François Moine
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <drm/drmP.h>
+#include <drm/drm_fb_cma_helper.h>
+
+struct lcd;
+
+#define N_LCDS 2
+
+/* SoC types */
+#define SOC_A83T 0
+#define SOC_H3 1
+
+struct priv {
+	void __iomem *mmio;
+	struct clk *clk;
+	struct clk *gate;
+	struct reset_control *rstc;
+
+	int soc_type;
+
+	struct drm_fbdev_cma *fbdev;
+
+	struct lcd *lcds[N_LCDS];
+};
+
+/* in de2_crtc.c */
+int de2_enable_vblank(struct drm_device *drm, unsigned crtc);
+void de2_disable_vblank(struct drm_device *drm, unsigned crtc);
+extern struct platform_driver de2_lcd_platform_driver;
+
+/* in de2_de.c */
+int de2_de_init(struct priv *priv, struct device *dev);
+void de2_de_cleanup(struct priv *priv);
+
+#endif /* __DE2_DRM_H__ */
diff --git a/drivers/gpu/drm/sunxi/de2_drv.c b/drivers/gpu/drm/sunxi/de2_drv.c
new file mode 100644
index 0000000..5daa15c
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/de2_drv.c
@@ -0,0 +1,378 @@ 
+/*
+ * Allwinner DRM driver - DE2 DRM driver
+ *
+ * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+#include <linux/component.h>
+#include <drm/drm_of.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+
+#include "de2_drm.h"
+
+#define DRIVER_NAME	"sunxi-de2"
+#define DRIVER_DESC	"Allwinner DRM DE2"
+#define DRIVER_DATE	"20161001"
+#define DRIVER_MAJOR	1
+#define DRIVER_MINOR	0
+
+static struct of_device_id de2_drm_of_match[] = {
+	{ .compatible = "allwinner,sun8i-a83t-display-engine",
+				.data = (void *) SOC_A83T },
+	{ .compatible = "allwinner,sun8i-h3-display-engine",
+				.data = (void *) SOC_H3 },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, de2_drm_of_match);
+
+static void de2_fb_output_poll_changed(struct drm_device *drm)
+{
+	struct priv *priv = drm->dev_private;
+
+	if (priv->fbdev)
+		drm_fbdev_cma_hotplug_event(priv->fbdev);
+}
+
+static const struct drm_mode_config_funcs de2_mode_config_funcs = {
+	.fb_create = drm_fb_cma_create,
+	.output_poll_changed = de2_fb_output_poll_changed,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+/*
+ * DRM operations:
+ */
+static void de2_lastclose(struct drm_device *drm)
+{
+	struct priv *priv = drm->dev_private;
+
+	if (priv->fbdev)
+		drm_fbdev_cma_restore_mode(priv->fbdev);
+}
+
+static const struct file_operations de2_fops = {
+	.owner		= THIS_MODULE,
+	.open		= drm_open,
+	.release	= drm_release,
+	.unlocked_ioctl	= drm_ioctl,
+	.poll		= drm_poll,
+	.read		= drm_read,
+	.llseek		= no_llseek,
+	.mmap		= drm_gem_cma_mmap,
+};
+
+static struct drm_driver de2_drm_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
+					DRIVER_ATOMIC,
+	.lastclose		= de2_lastclose,
+	.get_vblank_counter	= drm_vblank_no_hw_counter,
+	.enable_vblank		= de2_enable_vblank,
+	.disable_vblank		= de2_disable_vblank,
+	.gem_free_object	= drm_gem_cma_free_object,
+	.gem_vm_ops		= &drm_gem_cma_vm_ops,
+	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
+	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
+	.gem_prime_import	= drm_gem_prime_import,
+	.gem_prime_export	= drm_gem_prime_export,
+	.gem_prime_get_sg_table	= drm_gem_cma_prime_get_sg_table,
+	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
+	.gem_prime_vmap		= drm_gem_cma_prime_vmap,
+	.gem_prime_vunmap	= drm_gem_cma_prime_vunmap,
+	.gem_prime_mmap		= drm_gem_cma_prime_mmap,
+	.dumb_create		= drm_gem_cma_dumb_create,
+	.dumb_map_offset	= drm_gem_cma_dumb_map_offset,
+	.dumb_destroy		= drm_gem_dumb_destroy,
+	.fops			= &de2_fops,
+	.name			= DRIVER_NAME,
+	.desc			= DRIVER_DESC,
+	.date			= DRIVER_DATE,
+	.major			= DRIVER_MAJOR,
+	.minor			= DRIVER_MINOR,
+};
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * Power management
+ */
+static int de2_pm_suspend(struct device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(dev);
+
+	drm_kms_helper_poll_disable(drm);
+	return 0;
+}
+
+static int de2_pm_resume(struct device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(dev);
+
+	drm_kms_helper_poll_enable(drm);
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops de2_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(de2_pm_suspend, de2_pm_resume)
+};
+
+/*
+ * Platform driver
+ */
+
+static int de2_drm_bind(struct device *dev)
+{
+	struct drm_device *drm;
+	struct priv *priv;
+	int ret;
+
+	drm = drm_dev_alloc(&de2_drm_driver, dev);
+	if (!drm)
+		return -ENOMEM;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(dev, "failed to allocate private area\n");
+		ret = -ENOMEM;
+		goto out1;
+	}
+
+	dev_set_drvdata(dev, drm);
+	drm->dev_private = priv;
+
+	drm_mode_config_init(drm);
+	drm->mode_config.min_width = 32;	/* needed for cursor */
+	drm->mode_config.min_height = 32;
+	drm->mode_config.max_width = 1920;
+	drm->mode_config.max_height = 1080;
+	drm->mode_config.funcs = &de2_mode_config_funcs;
+
+	drm->irq_enabled = true;
+
+	/* initialize the display engine */
+	priv->soc_type = (int) of_match_device(de2_drm_of_match, dev)->data;
+	ret = de2_de_init(priv, dev);
+	if (ret)
+		goto out2;
+
+	/* start the subdevices */
+	ret = component_bind_all(dev, drm);
+	if (ret < 0)
+		goto out2;
+
+	ret = drm_dev_register(drm, 0);
+	if (ret < 0)
+		goto out3;
+
+	DRM_DEBUG_DRIVER("%d crtcs %d connectors\n",
+			 drm->mode_config.num_crtc,
+			 drm->mode_config.num_connector);
+
+	ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
+	if (ret < 0)
+		dev_warn(dev, "failed to initialize vblank\n");
+
+	drm_mode_config_reset(drm);
+
+	priv->fbdev = drm_fbdev_cma_init(drm,
+					32,	/* bpp */
+					drm->mode_config.num_crtc,
+					drm->mode_config.num_connector);
+	if (IS_ERR(priv->fbdev)) {
+		ret = PTR_ERR(priv->fbdev);
+		priv->fbdev = NULL;
+		goto out4;
+	}
+
+	drm_kms_helper_poll_init(drm);
+
+	return 0;
+
+out4:
+	drm_dev_unregister(drm);
+out3:
+	component_unbind_all(dev, drm);
+out2:
+	kfree(priv);
+out1:
+	drm_dev_unref(drm);
+	return ret;
+}
+
+static void de2_drm_unbind(struct device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(dev);
+	struct priv *priv = drm->dev_private;
+
+	if (priv)
+		drm_fbdev_cma_fini(priv->fbdev);
+	drm_kms_helper_poll_fini(drm);
+
+	drm_dev_unregister(drm);
+	drm_vblank_cleanup(drm);
+
+	drm_mode_config_cleanup(drm);
+
+	component_unbind_all(dev, drm);
+
+	if (priv) {
+		de2_de_cleanup(priv);
+		kfree(priv);
+	}
+
+	drm_dev_unref(drm);
+}
+
+static const struct component_master_ops de2_drm_comp_ops = {
+	.bind = de2_drm_bind,
+	.unbind = de2_drm_unbind,
+};
+
+static int compare_of(struct device *dev, void *data)
+{
+	return dev->of_node == data;
+}
+
+static int de2_drm_add_components(struct device *dev,
+				  int (*compare_of)(struct device *, void *),
+				  const struct component_master_ops *m_ops)
+{
+	struct device_node *ep, *port, *remote;
+	struct component_match *match = NULL;
+	int i;
+
+	if (!dev->of_node)
+		return -EINVAL;
+
+	/* bind the CRTCs */
+	for (i = 0; ; i++) {
+		port = of_parse_phandle(dev->of_node, "ports", i);
+		if (!port)
+			break;
+
+		if (!of_device_is_available(port->parent)) {
+			of_node_put(port);
+			continue;
+		}
+
+		component_match_add(dev, &match, compare_of, port->parent);
+		of_node_put(port);
+	}
+
+	if (i == 0) {
+		dev_err(dev, "missing 'ports' property\n");
+		return -ENODEV;
+	}
+	if (!match) {
+		dev_err(dev, "no available port\n");
+		return -ENODEV;
+	}
+
+	/* bind the encoders/connectors */
+	for (i = 0; ; i++) {
+		port = of_parse_phandle(dev->of_node, "ports", i);
+		if (!port)
+			break;
+
+		if (!of_device_is_available(port->parent)) {
+			of_node_put(port);
+			continue;
+		}
+
+		for_each_child_of_node(port, ep) {
+			remote = of_graph_get_remote_port_parent(ep);
+			if (!remote || !of_device_is_available(remote)) {
+				of_node_put(remote);
+				continue;
+			}
+			if (!of_device_is_available(remote->parent)) {
+				dev_warn(dev,
+					"parent device of %s is not available\n",
+					remote->full_name);
+				of_node_put(remote);
+				continue;
+			}
+
+			component_match_add(dev, &match, compare_of, remote);
+			of_node_put(remote);
+		}
+		of_node_put(port);
+	}
+
+	return component_master_add_with_match(dev, m_ops, match);
+}
+
+static int de2_drm_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = de2_drm_add_components(&pdev->dev,
+				     compare_of,
+				     &de2_drm_comp_ops);
+	if (ret == -EINVAL)
+		ret = -ENXIO;
+	return ret;
+}
+
+static int de2_drm_remove(struct platform_device *pdev)
+{
+	component_master_del(&pdev->dev, &de2_drm_comp_ops);
+
+	return 0;
+}
+
+static struct platform_driver de2_drm_platform_driver = {
+	.probe      = de2_drm_probe,
+	.remove     = de2_drm_remove,
+	.driver     = {
+		.name = DRIVER_NAME,
+		.pm = &de2_pm_ops,
+		.of_match_table = de2_drm_of_match,
+	},
+};
+
+static int __init de2_drm_init(void)
+{
+	int ret;
+
+/* uncomment to activate the drm traces at startup time */
+/*	drm_debug = DRM_UT_CORE | DRM_UT_DRIVER | DRM_UT_KMS |
+			DRM_UT_PRIME | DRM_UT_ATOMIC; */
+
+	DRM_DEBUG_DRIVER("\n");
+
+	ret = platform_driver_register(&de2_lcd_platform_driver);
+	if (ret < 0)
+		return ret;
+
+	ret = platform_driver_register(&de2_drm_platform_driver);
+	if (ret < 0)
+		platform_driver_unregister(&de2_lcd_platform_driver);
+
+	return ret;
+}
+
+static void __exit de2_drm_fini(void)
+{
+	platform_driver_unregister(&de2_lcd_platform_driver);
+	platform_driver_unregister(&de2_drm_platform_driver);
+}
+
+module_init(de2_drm_init);
+module_exit(de2_drm_fini);
+
+MODULE_AUTHOR("Jean-Francois Moine <moinejf@free.fr>");
+MODULE_DESCRIPTION("Allwinner DE2 DRM Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/sunxi/de2_plane.c b/drivers/gpu/drm/sunxi/de2_plane.c
new file mode 100644
index 0000000..b338684
--- /dev/null
+++ b/drivers/gpu/drm/sunxi/de2_plane.c
@@ -0,0 +1,119 @@ 
+/*
+ * Allwinner DRM driver - DE2 planes
+ *
+ * Copyright (C) 2016 Jean-Francois Moine <moinejf@free.fr>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_plane_helper.h>
+#include <drm/drm_crtc_helper.h>
+
+#include "de2_drm.h"
+#include "de2_crtc.h"
+
+/* plane formats */
+static const uint32_t ui_formats[] = {
+	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_BGRA8888,
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_RGB888,
+	DRM_FORMAT_BGR888,
+};
+
+static const uint32_t vi_formats[] = {
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_YUYV,
+	DRM_FORMAT_YVYU,
+	DRM_FORMAT_YUV422,
+	DRM_FORMAT_YUV420,
+	DRM_FORMAT_UYVY,
+	DRM_FORMAT_BGRA8888,
+	DRM_FORMAT_RGB888,
+	DRM_FORMAT_BGR888,
+};
+
+static void de2_plane_disable(struct drm_plane *plane,
+				struct drm_plane_state *old_state)
+{
+	struct drm_crtc *crtc = old_state->crtc;
+	struct lcd *lcd = crtc_to_lcd(crtc);
+	int plane_num = plane - lcd->planes;
+
+	de2_de_plane_disable(lcd->priv, lcd->num, plane_num);
+}
+
+static void de2_plane_update(struct drm_plane *plane,
+				struct drm_plane_state *old_state)
+{
+	struct drm_plane_state *state = plane->state;
+	struct drm_crtc *crtc = state->crtc;
+	struct lcd *lcd = crtc_to_lcd(crtc);
+	struct drm_framebuffer *fb = state->fb;
+	int plane_num = plane - lcd->planes;
+
+	if (!crtc || !fb) {
+		DRM_DEBUG_DRIVER("no crtc/fb\n");
+		return;
+	}
+
+	de2_de_plane_update(lcd->priv, lcd->num, plane_num,
+			    state, old_state);
+}
+
+static const struct drm_plane_helper_funcs plane_helper_funcs = {
+	.atomic_disable = de2_plane_disable,
+	.atomic_update = de2_plane_update,
+};
+
+static const struct drm_plane_funcs plane_funcs = {
+	.update_plane = drm_atomic_helper_update_plane,
+	.disable_plane = drm_atomic_helper_disable_plane,
+	.destroy = drm_plane_cleanup,
+	.reset = drm_atomic_helper_plane_reset,
+	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
+};
+
+static int de2_one_plane_init(struct drm_device *drm,
+				struct drm_plane *plane,
+				int type, int possible_crtcs,
+				const uint32_t *formats,
+				int nformats)
+{
+	int ret;
+
+	ret = drm_universal_plane_init(drm, plane, possible_crtcs,
+				&plane_funcs,
+				formats, nformats, type, NULL);
+	if (ret >= 0)
+		drm_plane_helper_add(plane, &plane_helper_funcs);
+
+	return ret;
+}
+
+int de2_plane_init(struct drm_device *drm, struct lcd *lcd)
+{
+	int ret, possible_crtcs = 1 << lcd->crtc_idx;
+
+	ret = de2_one_plane_init(drm, &lcd->planes[DE2_PRIMARY_PLANE],
+				DRM_PLANE_TYPE_PRIMARY, possible_crtcs,
+				ui_formats, ARRAY_SIZE(ui_formats));
+	if (ret >= 0)
+		ret = de2_one_plane_init(drm, &lcd->planes[DE2_CURSOR_PLANE],
+				DRM_PLANE_TYPE_CURSOR, possible_crtcs,
+				ui_formats, ARRAY_SIZE(ui_formats));
+	if (ret >= 0)
+		ret = de2_one_plane_init(drm, &lcd->planes[DE2_VI_PLANE],
+				DRM_PLANE_TYPE_OVERLAY, possible_crtcs,
+				vi_formats, ARRAY_SIZE(vi_formats));
+	if (ret < 0)
+		dev_err(lcd->dev, "Couldn't initialize the planes err %d\n",
+				ret);
+
+	return ret;
+}