diff mbox

[v5,05/11] drm/sun4i: abstract a engine type

Message ID 20170423103754.50012-6-icenowy@aosc.io (mailing list archive)
State Superseded
Headers show

Commit Message

Icenowy Zheng April 23, 2017, 10:37 a.m. UTC
As we are going to add support for the Allwinner DE2 engine in sun4i-drm
driver, we will finally have two types of display engines -- the DE1
backend and the DE2 mixer. They both do some display blending and feed
graphics data to TCON, so I choose to call them both "engine" here.

Abstract the engine type to a new struct with an ops struct, which contains
functions that should be called outside the engine-specified code (in
TCON, CRTC or TV Encoder code).

A dedicated Kconfig option is also added to control whether
sun4i-backend-specified code (sun4i_backend.c and sun4i_layer.c) should
be built. As we removed the codes in CRTC code that directly call the
layer code, we can now extract the layer part and combine it with the
backend part into a new module, sun4i-backend.ko.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
---
Changes in v5:
- Really made a sunxi_engine struct type, and moved ops pointer
  into it.
- Added checked ops wrappers.
- Changed the second parameter of layers_init from crtc to engine.
Changes in v4:
- Comments to tag the color correction functions as optional.
- Check before calling the optional functions.
- Change layers_init to satisfy new PATCH v4 04/11.

 drivers/gpu/drm/sun4i/Kconfig         | 10 ++++
 drivers/gpu/drm/sun4i/Makefile        |  6 ++-
 drivers/gpu/drm/sun4i/sun4i_backend.c | 68 ++++++++++++++------------
 drivers/gpu/drm/sun4i/sun4i_backend.h | 13 +++--
 drivers/gpu/drm/sun4i/sun4i_crtc.c    | 11 ++---
 drivers/gpu/drm/sun4i/sun4i_crtc.h    |  4 +-
 drivers/gpu/drm/sun4i/sun4i_drv.h     |  2 +-
 drivers/gpu/drm/sun4i/sun4i_layer.c   |  8 ++-
 drivers/gpu/drm/sun4i/sun4i_layer.h   |  5 +-
 drivers/gpu/drm/sun4i/sun4i_tcon.c    |  2 +-
 drivers/gpu/drm/sun4i/sun4i_tv.c      |  9 ++--
 drivers/gpu/drm/sun4i/sunxi_engine.h  | 91 +++++++++++++++++++++++++++++++++++
 12 files changed, 169 insertions(+), 60 deletions(-)
 create mode 100644 drivers/gpu/drm/sun4i/sunxi_engine.h

Comments

Maxime Ripard April 24, 2017, 9:05 a.m. UTC | #1
Hi,

Thanks a lot for that work.

On Sun, Apr 23, 2017 at 06:37:48PM +0800, Icenowy Zheng wrote:
> As we are going to add support for the Allwinner DE2 engine in sun4i-drm
> driver, we will finally have two types of display engines -- the DE1
> backend and the DE2 mixer. They both do some display blending and feed
> graphics data to TCON, so I choose to call them both "engine" here.
> 
> Abstract the engine type to a new struct with an ops struct, which contains
> functions that should be called outside the engine-specified code (in
> TCON, CRTC or TV Encoder code).
> 
> A dedicated Kconfig option is also added to control whether
> sun4i-backend-specified code (sun4i_backend.c and sun4i_layer.c) should
> be built. As we removed the codes in CRTC code that directly call the
> layer code, we can now extract the layer part and combine it with the
> backend part into a new module, sun4i-backend.ko.

While the code itself is good now, the patch mixes a few things that
would be better to be split in separate patches. I think it would be
better if you had patches organized like this:
  - Abstract the engine type by create the sunxi_engine structure and
    fixing all the callers.
  - Move the layers and backend files in the same module, and remove
    the now useless EXPORT_SYMBOLS.
  - Create a Kconfig option.

Thanks!
Maxime
diff mbox

Patch

diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
index a4b357db8856..5a8227f37cc4 100644
--- a/drivers/gpu/drm/sun4i/Kconfig
+++ b/drivers/gpu/drm/sun4i/Kconfig
@@ -12,3 +12,13 @@  config DRM_SUN4I
 	  Choose this option if you have an Allwinner SoC with a
 	  Display Engine. If M is selected the module will be called
 	  sun4i-drm.
+
+config DRM_SUN4I_BACKEND
+	tristate "Support for Allwinner A10 Display Engine Backend"
+	depends on DRM_SUN4I
+	default DRM_SUN4I
+	help
+	  Choose this option if you have an Allwinner SoC with the
+	  original Allwinner Display Engine, which has a backend to
+	  do some alpha blending and feed graphics to TCON. If M is
+	  selected the module will be called sun4i-backend.
diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
index 59b757350a1f..1db1068b9be1 100644
--- a/drivers/gpu/drm/sun4i/Makefile
+++ b/drivers/gpu/drm/sun4i/Makefile
@@ -5,9 +5,11 @@  sun4i-tcon-y += sun4i_tcon.o
 sun4i-tcon-y += sun4i_rgb.o
 sun4i-tcon-y += sun4i_dotclock.o
 sun4i-tcon-y += sun4i_crtc.o
-sun4i-tcon-y += sun4i_layer.o
+
+sun4i-backend-y += sun4i_layer.o
+sun4i-backend-y += sun4i_backend.o
 
 obj-$(CONFIG_DRM_SUN4I)		+= sun4i-drm.o sun4i-tcon.o
-obj-$(CONFIG_DRM_SUN4I)		+= sun4i_backend.o
+obj-$(CONFIG_DRM_SUN4I_BACKEND)	+= sun4i-backend.o
 obj-$(CONFIG_DRM_SUN4I)		+= sun6i_drc.o
 obj-$(CONFIG_DRM_SUN4I)		+= sun4i_tv.o
diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index d660741ba475..360ab046121b 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -23,6 +23,8 @@ 
 
 #include "sun4i_backend.h"
 #include "sun4i_drv.h"
+#include "sun4i_layer.h"
+#include "sunxi_engine.h"
 
 static const u32 sunxi_rgb2yuv_coef[12] = {
 	0x00000107, 0x00000204, 0x00000064, 0x00000108,
@@ -30,41 +32,38 @@  static const u32 sunxi_rgb2yuv_coef[12] = {
 	0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
 };
 
-void sun4i_backend_apply_color_correction(struct sun4i_backend *backend)
+static void sun4i_backend_apply_color_correction(struct sunxi_engine *engine)
 {
 	int i;
 
 	DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
 
 	/* Set color correction */
-	regmap_write(backend->regs, SUN4I_BACKEND_OCCTL_REG,
+	regmap_write(engine->regs, SUN4I_BACKEND_OCCTL_REG,
 		     SUN4I_BACKEND_OCCTL_ENABLE);
 
 	for (i = 0; i < 12; i++)
-		regmap_write(backend->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
+		regmap_write(engine->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
 			     sunxi_rgb2yuv_coef[i]);
 }
-EXPORT_SYMBOL(sun4i_backend_apply_color_correction);
 
-void sun4i_backend_disable_color_correction(struct sun4i_backend *backend)
+static void sun4i_backend_disable_color_correction(struct sunxi_engine *engine)
 {
 	DRM_DEBUG_DRIVER("Disabling color correction\n");
 
 	/* Disable color correction */
-	regmap_update_bits(backend->regs, SUN4I_BACKEND_OCCTL_REG,
+	regmap_update_bits(engine->regs, SUN4I_BACKEND_OCCTL_REG,
 			   SUN4I_BACKEND_OCCTL_ENABLE, 0);
 }
-EXPORT_SYMBOL(sun4i_backend_disable_color_correction);
 
-void sun4i_backend_commit(struct sun4i_backend *backend)
+static void sun4i_backend_commit(struct sunxi_engine *engine)
 {
 	DRM_DEBUG_DRIVER("Committing changes\n");
 
-	regmap_write(backend->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
+	regmap_write(engine->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
 		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
 		     SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
 }
-EXPORT_SYMBOL(sun4i_backend_commit);
 
 void sun4i_backend_layer_enable(struct sun4i_backend *backend,
 				int layer, bool enable)
@@ -78,10 +77,9 @@  void sun4i_backend_layer_enable(struct sun4i_backend *backend,
 	else
 		val = 0;
 
-	regmap_update_bits(backend->regs, SUN4I_BACKEND_MODCTL_REG,
+	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 			   SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
 }
-EXPORT_SYMBOL(sun4i_backend_layer_enable);
 
 static int sun4i_backend_drm_format_to_layer(struct drm_plane *plane,
 					     u32 format, u32 *mode)
@@ -141,33 +139,33 @@  int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
 	if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
 		DRM_DEBUG_DRIVER("Primary layer, updating global size W: %u H: %u\n",
 				 state->crtc_w, state->crtc_h);
-		regmap_write(backend->regs, SUN4I_BACKEND_DISSIZE_REG,
+		regmap_write(backend->engine.regs, SUN4I_BACKEND_DISSIZE_REG,
 			     SUN4I_BACKEND_DISSIZE(state->crtc_w,
 						   state->crtc_h));
 	}
 
 	/* Set the line width */
 	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
-	regmap_write(backend->regs, SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
+	regmap_write(backend->engine.regs,
+		     SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
 		     fb->pitches[0] * 8);
 
 	/* Set height and width */
 	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
 			 state->crtc_w, state->crtc_h);
-	regmap_write(backend->regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
+	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
 		     SUN4I_BACKEND_LAYSIZE(state->crtc_w,
 					   state->crtc_h));
 
 	/* Set base coordinates */
 	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
 			 state->crtc_x, state->crtc_y);
-	regmap_write(backend->regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
+	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
 		     SUN4I_BACKEND_LAYCOOR(state->crtc_x,
 					   state->crtc_y));
 
 	return 0;
 }
-EXPORT_SYMBOL(sun4i_backend_update_layer_coord);
 
 int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
 				       int layer, struct drm_plane *plane)
@@ -182,7 +180,7 @@  int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
 		interlaced = plane->state->crtc->state->adjusted_mode.flags
 			& DRM_MODE_FLAG_INTERLACE;
 
-	regmap_update_bits(backend->regs, SUN4I_BACKEND_MODCTL_REG,
+	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 			   SUN4I_BACKEND_MODCTL_ITLMOD_EN,
 			   interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
 
@@ -196,12 +194,12 @@  int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
 		return ret;
 	}
 
-	regmap_update_bits(backend->regs, SUN4I_BACKEND_ATTCTL_REG1(layer),
+	regmap_update_bits(backend->engine.regs,
+			   SUN4I_BACKEND_ATTCTL_REG1(layer),
 			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
 
 	return 0;
 }
-EXPORT_SYMBOL(sun4i_backend_update_layer_formats);
 
 int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
 				      int layer, struct drm_plane *plane)
@@ -229,19 +227,19 @@  int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
 	/* Write the 32 lower bits of the address (in bits) */
 	lo_paddr = paddr << 3;
 	DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
-	regmap_write(backend->regs, SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
+	regmap_write(backend->engine.regs,
+		     SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
 		     lo_paddr);
 
 	/* And the upper bits */
 	hi_paddr = paddr >> 29;
 	DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
-	regmap_update_bits(backend->regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
+	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
 			   SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
 			   SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
 
 	return 0;
 }
-EXPORT_SYMBOL(sun4i_backend_update_layer_buffer);
 
 static int sun4i_backend_init_sat(struct device *dev) {
 	struct sun4i_backend *backend = dev_get_drvdata(dev);
@@ -288,6 +286,13 @@  static int sun4i_backend_free_sat(struct device *dev) {
 	return 0;
 }
 
+static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
+	.commit				= sun4i_backend_commit,
+	.layers_init			= sun4i_layers_init,
+	.apply_color_correction		= sun4i_backend_apply_color_correction,
+	.disable_color_correction	= sun4i_backend_disable_color_correction,
+};
+
 static struct regmap_config sun4i_backend_regmap_config = {
 	.reg_bits	= 32,
 	.val_bits	= 32,
@@ -310,18 +315,19 @@  static int sun4i_backend_bind(struct device *dev, struct device *master,
 	if (!backend)
 		return -ENOMEM;
 	dev_set_drvdata(dev, backend);
-	drv->backend = backend;
+	drv->engine = &backend->engine;
+	drv->engine->ops = &sun4i_backend_engine_ops;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	regs = devm_ioremap_resource(dev, res);
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);
 
-	backend->regs = devm_regmap_init_mmio(dev, regs,
-					      &sun4i_backend_regmap_config);
-	if (IS_ERR(backend->regs)) {
+	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
+						&sun4i_backend_regmap_config);
+	if (IS_ERR(backend->engine.regs)) {
 		dev_err(dev, "Couldn't create the backend0 regmap\n");
-		return PTR_ERR(backend->regs);
+		return PTR_ERR(backend->engine.regs);
 	}
 
 	backend->reset = devm_reset_control_get(dev, NULL);
@@ -371,14 +377,14 @@  static int sun4i_backend_bind(struct device *dev, struct device *master,
 
 	/* Reset the registers */
 	for (i = 0x800; i < 0x1000; i += 4)
-		regmap_write(backend->regs, i, 0);
+		regmap_write(backend->engine.regs, i, 0);
 
 	/* Disable registers autoloading */
-	regmap_write(backend->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
+	regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
 		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
 
 	/* Enable the backend */
-	regmap_write(backend->regs, SUN4I_BACKEND_MODCTL_REG,
+	regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 		     SUN4I_BACKEND_MODCTL_DEBE_EN |
 		     SUN4I_BACKEND_MODCTL_START_CTL);
 
diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.h b/drivers/gpu/drm/sun4i/sun4i_backend.h
index 83e63cc702b4..a92f50eca948 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.h
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.h
@@ -17,6 +17,8 @@ 
 #include <linux/regmap.h>
 #include <linux/reset.h>
 
+#include "sunxi_engine.h"
+
 #define SUN4I_BACKEND_MODCTL_REG		0x800
 #define SUN4I_BACKEND_MODCTL_LINE_SEL			BIT(29)
 #define SUN4I_BACKEND_MODCTL_ITLMOD_EN			BIT(28)
@@ -139,7 +141,7 @@ 
 #define SUN4I_BACKEND_PIPE_OFF(p)		(0x5000 + (0x400 * (p)))
 
 struct sun4i_backend {
-	struct regmap		*regs;
+	struct sunxi_engine	engine;
 
 	struct reset_control	*reset;
 
@@ -151,10 +153,11 @@  struct sun4i_backend {
 	struct reset_control	*sat_reset;
 };
 
-void sun4i_backend_apply_color_correction(struct sun4i_backend *backend);
-void sun4i_backend_disable_color_correction(struct sun4i_backend *backend);
-
-void sun4i_backend_commit(struct sun4i_backend *backend);
+static inline struct sun4i_backend *
+engine_to_sun4i_backend(struct sunxi_engine *engine)
+{
+	return container_of(engine, struct sun4i_backend, engine);
+}
 
 void sun4i_backend_layer_enable(struct sun4i_backend *backend,
 				int layer, bool enable);
diff --git a/drivers/gpu/drm/sun4i/sun4i_crtc.c b/drivers/gpu/drm/sun4i/sun4i_crtc.c
index 708b3543d4e9..f8c70439d1e2 100644
--- a/drivers/gpu/drm/sun4i/sun4i_crtc.c
+++ b/drivers/gpu/drm/sun4i/sun4i_crtc.c
@@ -25,10 +25,9 @@ 
 
 #include <video/videomode.h>
 
-#include "sun4i_backend.h"
 #include "sun4i_crtc.h"
 #include "sun4i_drv.h"
-#include "sun4i_layer.h"
+#include "sunxi_engine.h"
 #include "sun4i_tcon.h"
 
 static void sun4i_crtc_atomic_begin(struct drm_crtc *crtc,
@@ -56,7 +55,7 @@  static void sun4i_crtc_atomic_flush(struct drm_crtc *crtc,
 
 	DRM_DEBUG_DRIVER("Committing plane changes\n");
 
-	sun4i_backend_commit(scrtc->backend);
+	sunxi_engine_commit(scrtc->engine);
 
 	if (event) {
 		crtc->state->event = NULL;
@@ -135,7 +134,7 @@  static const struct drm_crtc_funcs sun4i_crtc_funcs = {
 };
 
 struct sun4i_crtc *sun4i_crtc_init(struct drm_device *drm,
-				   struct sun4i_backend *backend,
+				   struct sunxi_engine *engine,
 				   struct sun4i_tcon *tcon)
 {
 	struct sun4i_crtc *scrtc;
@@ -146,11 +145,11 @@  struct sun4i_crtc *sun4i_crtc_init(struct drm_device *drm,
 	scrtc = devm_kzalloc(drm->dev, sizeof(*scrtc), GFP_KERNEL);
 	if (!scrtc)
 		return ERR_PTR(-ENOMEM);
-	scrtc->backend = backend;
+	scrtc->engine = engine;
 	scrtc->tcon = tcon;
 
 	/* Create our layers */
-	planes = sun4i_layers_init(drm, scrtc);
+	planes = sunxi_engine_layers_init(drm, engine);
 	if (IS_ERR(planes)) {
 		dev_err(drm->dev, "Couldn't create the planes\n");
 		return NULL;
diff --git a/drivers/gpu/drm/sun4i/sun4i_crtc.h b/drivers/gpu/drm/sun4i/sun4i_crtc.h
index 4dae3508424a..bf0ce36eb518 100644
--- a/drivers/gpu/drm/sun4i/sun4i_crtc.h
+++ b/drivers/gpu/drm/sun4i/sun4i_crtc.h
@@ -17,7 +17,7 @@  struct sun4i_crtc {
 	struct drm_crtc			crtc;
 	struct drm_pending_vblank_event	*event;
 
-	struct sun4i_backend		*backend;
+	struct sunxi_engine		*engine;
 	struct sun4i_tcon		*tcon;
 };
 
@@ -27,7 +27,7 @@  static inline struct sun4i_crtc *drm_crtc_to_sun4i_crtc(struct drm_crtc *crtc)
 }
 
 struct sun4i_crtc *sun4i_crtc_init(struct drm_device *drm,
-				   struct sun4i_backend *backend,
+				   struct sunxi_engine *engine,
 				   struct sun4i_tcon *tcon);
 
 #endif /* _SUN4I_CRTC_H_ */
diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.h b/drivers/gpu/drm/sun4i/sun4i_drv.h
index 5df50126ff52..dee8e88e99b0 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.h
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.h
@@ -17,7 +17,7 @@ 
 #include <linux/regmap.h>
 
 struct sun4i_drv {
-	struct sun4i_backend	*backend;
+	struct sunxi_engine	*engine;
 	struct sun4i_tcon	*tcon;
 
 	struct drm_fbdev_cma	*fbdev;
diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.c b/drivers/gpu/drm/sun4i/sun4i_layer.c
index e1f03e1cc0ac..ab33e4d06782 100644
--- a/drivers/gpu/drm/sun4i/sun4i_layer.c
+++ b/drivers/gpu/drm/sun4i/sun4i_layer.c
@@ -11,12 +11,10 @@ 
  */
 
 #include <drm/drm_atomic_helper.h>
-#include <drm/drm_crtc.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drmP.h>
 
 #include "sun4i_backend.h"
-#include "sun4i_crtc.h"
 #include "sun4i_layer.h"
 
 struct sun4i_plane_desc {
@@ -130,10 +128,10 @@  static struct sun4i_layer *sun4i_layer_init_one(struct drm_device *drm,
 }
 
 struct drm_plane **sun4i_layers_init(struct drm_device *drm,
-				     struct sun4i_crtc *crtc)
+				     struct sunxi_engine *engine)
 {
 	struct drm_plane **planes;
-	struct sun4i_backend *backend = crtc->backend;
+	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
 	int i;
 
 	planes = devm_kcalloc(drm->dev, ARRAY_SIZE(sun4i_backend_planes) + 1,
@@ -175,7 +173,7 @@  struct drm_plane **sun4i_layers_init(struct drm_device *drm,
 
 		DRM_DEBUG_DRIVER("Assigning %s plane to pipe %d\n",
 				 i ? "overlay" : "primary", plane->pipe);
-		regmap_update_bits(backend->regs, SUN4I_BACKEND_ATTCTL_REG0(i),
+		regmap_update_bits(engine->regs, SUN4I_BACKEND_ATTCTL_REG0(i),
 				   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK,
 				   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(plane->pipe));
 
diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.h b/drivers/gpu/drm/sun4i/sun4i_layer.h
index 5ea5c994d6ea..004b7cfe8ffb 100644
--- a/drivers/gpu/drm/sun4i/sun4i_layer.h
+++ b/drivers/gpu/drm/sun4i/sun4i_layer.h
@@ -13,6 +13,8 @@ 
 #ifndef _SUN4I_LAYER_H_
 #define _SUN4I_LAYER_H_
 
+struct sunxi_engine;
+
 struct sun4i_layer {
 	struct drm_plane	plane;
 	struct sun4i_drv	*drv;
@@ -27,6 +29,5 @@  plane_to_sun4i_layer(struct drm_plane *plane)
 }
 
 struct drm_plane **sun4i_layers_init(struct drm_device *drm,
-				     struct sun4i_crtc *crtc);
-
+				     struct sunxi_engine *engine);
 #endif /* _SUN4I_LAYER_H_ */
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 9a83a85529ac..e4fef0639656 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -459,7 +459,7 @@  static int sun4i_tcon_bind(struct device *dev, struct device *master,
 		goto err_free_dotclock;
 	}
 
-	tcon->crtc = sun4i_crtc_init(drm, drv->backend, tcon);
+	tcon->crtc = sun4i_crtc_init(drm, drv->engine, tcon);
 	if (IS_ERR(tcon->crtc)) {
 		dev_err(dev, "Couldn't create our CRTC\n");
 		ret = PTR_ERR(tcon->crtc);
diff --git a/drivers/gpu/drm/sun4i/sun4i_tv.c b/drivers/gpu/drm/sun4i/sun4i_tv.c
index 49c49431a053..e598594ccea2 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tv.c
@@ -22,10 +22,10 @@ 
 #include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 
-#include "sun4i_backend.h"
 #include "sun4i_crtc.h"
 #include "sun4i_drv.h"
 #include "sun4i_tcon.h"
+#include "sunxi_engine.h"
 
 #define SUN4I_TVE_EN_REG		0x000
 #define SUN4I_TVE_EN_DAC_MAP_MASK		GENMASK(19, 4)
@@ -353,7 +353,6 @@  static void sun4i_tv_disable(struct drm_encoder *encoder)
 	struct sun4i_tv *tv = drm_encoder_to_sun4i_tv(encoder);
 	struct sun4i_crtc *crtc = drm_crtc_to_sun4i_crtc(encoder->crtc);
 	struct sun4i_tcon *tcon = crtc->tcon;
-	struct sun4i_backend *backend = crtc->backend;
 
 	DRM_DEBUG_DRIVER("Disabling the TV Output\n");
 
@@ -362,7 +361,8 @@  static void sun4i_tv_disable(struct drm_encoder *encoder)
 	regmap_update_bits(tv->regs, SUN4I_TVE_EN_REG,
 			   SUN4I_TVE_EN_ENABLE,
 			   0);
-	sun4i_backend_disable_color_correction(backend);
+
+	sunxi_engine_disable_color_correction(crtc->engine);
 }
 
 static void sun4i_tv_enable(struct drm_encoder *encoder)
@@ -370,11 +370,10 @@  static void sun4i_tv_enable(struct drm_encoder *encoder)
 	struct sun4i_tv *tv = drm_encoder_to_sun4i_tv(encoder);
 	struct sun4i_crtc *crtc = drm_crtc_to_sun4i_crtc(encoder->crtc);
 	struct sun4i_tcon *tcon = crtc->tcon;
-	struct sun4i_backend *backend = crtc->backend;
 
 	DRM_DEBUG_DRIVER("Enabling the TV Output\n");
 
-	sun4i_backend_apply_color_correction(backend);
+	sunxi_engine_apply_color_correction(crtc->engine);
 
 	regmap_update_bits(tv->regs, SUN4I_TVE_EN_REG,
 			   SUN4I_TVE_EN_ENABLE,
diff --git a/drivers/gpu/drm/sun4i/sunxi_engine.h b/drivers/gpu/drm/sun4i/sunxi_engine.h
new file mode 100644
index 000000000000..85790d2f5f62
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sunxi_engine.h
@@ -0,0 +1,91 @@ 
+/*
+ * Copyright (C) 2017 Icenowy Zheng <icenowy@aosc.io>
+ *
+ * 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.
+ */
+
+#ifndef _SUNXI_ENGINE_H_
+#define _SUNXI_ENGINE_H_
+
+struct sun4i_crtc;
+struct drm_plane;
+struct drm_device;
+
+struct sunxi_engine;
+
+struct sunxi_engine_ops {
+	void (*commit)(struct sunxi_engine *engine);
+	struct drm_plane **(*layers_init)(struct drm_device *drm,
+					  struct sunxi_engine *engine);
+
+	void (*apply_color_correction)(struct sunxi_engine *engine);
+	void (*disable_color_correction)(struct sunxi_engine *engine);
+};
+
+/**
+ * struct sunxi_engine - the common parts of an engine for sun4i-drm driver
+ * @ops:	the operations of the engine
+ * @regs:	the regmap of the engine
+ */
+struct sunxi_engine {
+	const struct sunxi_engine_ops	*ops;
+
+	struct regmap			*regs;
+};
+
+/**
+ * sunxi_engine_commit() - commit all changes of the engine
+ * @engine:	pointer to the engine
+ */
+static inline void
+sunxi_engine_commit(struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->commit)
+		engine->ops->commit(engine);
+}
+
+/**
+ * sunxi_engine_layers_init() - Create planes (layers) for the engine
+ * @drm:	pointer to the drm_device for which planes will be created
+ * @engine:	pointer to the engine
+ */
+static inline struct drm_plane **
+sunxi_engine_layers_init(struct drm_device *drm, struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->layers_init)
+		return engine->ops->layers_init(drm, engine);
+	return ERR_PTR(-ENOSYS);
+}
+
+/**
+ * sunxi_engine_apply_color_correction - Apply the RGB2YUV color correction
+ * @engine:	pointer to the engine
+ *
+ * This functionality is optional for an engine, however, if the engine is
+ * intended to be used with TV Encoder, the output will be incorrect
+ * without the color correction, due to TV Encoder expects the engine to
+ * output directly YUV signal.
+ */
+static inline void
+sunxi_engine_apply_color_correction(struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->apply_color_correction)
+		engine->ops->apply_color_correction(engine);
+}
+
+/**
+ * sunxi_engine_disable_color_correction - Disable the color space correction
+ * @engine:	pointer to the engine
+ *
+ * This function is paired with apply_color_correction().
+ */
+static inline void
+sunxi_engine_disable_color_correction(struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->disable_color_correction)
+		engine->ops->disable_color_correction(engine);
+}
+#endif /* _SUNXI_ENGINE_H_ */