[v3,3/6] drm/vs: Register DRM device

Commit Message

Keith Zhao Dec. 4, 2023, 12:33 p.m. UTC

Implement drm device registration interface

Signed-off-by: Keith Zhao <[e-mail]>
---
 MAINTAINERS                              |   1 +
 drivers/gpu/drm/Kconfig                  |   2 +
 drivers/gpu/drm/Makefile                 |   1 +
 drivers/gpu/drm/verisilicon/Kconfig      |  13 +
 drivers/gpu/drm/verisilicon/Makefile     |   6 +
 drivers/gpu/drm/verisilicon/vs_drv.c     | 316 +++++++++++++++++++++++
 drivers/gpu/drm/verisilicon/vs_drv.h     |  42 +++
 drivers/gpu/drm/verisilicon/vs_modeset.c |  39 +++
 drivers/gpu/drm/verisilicon/vs_modeset.h |  10 +
 9 files changed, 430 insertions(+)
 create mode 100644 drivers/gpu/drm/verisilicon/Kconfig
 create mode 100644 drivers/gpu/drm/verisilicon/Makefile
 create mode 100644 drivers/gpu/drm/verisilicon/vs_drv.c
 create mode 100644 drivers/gpu/drm/verisilicon/vs_drv.h
 create mode 100644 drivers/gpu/drm/verisilicon/vs_modeset.c
 create mode 100644 drivers/gpu/drm/verisilicon/vs_modeset.h

Comments

Philipp Zabel Dec. 4, 2023, 1:30 p.m. UTC | #1

Hi Keith,

On Mo, 2023-12-04 at 20:33 +0800, Keith Zhao wrote:
> Implement drm device registration interface
> 
> Signed-off-by: Keith Zhao <[e-mail]>
> ---
[...]
> diff --git a/drivers/gpu/drm/verisilicon/Kconfig b/drivers/gpu/drm/verisilicon/Kconfig
> new file mode 100644
> index 000000000000..e10fa97635aa
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/Kconfig
> @@ -0,0 +1,13 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config DRM_VERISILICON
> +	tristate "DRM Support for VeriSilicon"
> +	depends on DRM
> +	select DRM_KMS_HELPER
> +	select DRM_GEM_DMA_HELPER
> +	select CMA
> +	select DMA_CMA
> +	help
> +	  Choose this option if you have a VeriSilicon soc chipset.

This seems a bit generic. Doesn't the VeriSilicon display controller IP
used on JH7110 have a product name?

[...]
> diff --git a/drivers/gpu/drm/verisilicon/vs_drv.c b/drivers/gpu/drm/verisilicon/vs_drv.c
> new file mode 100644
> index 000000000000..4fb1f29ef84b
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/vs_drv.c
> @@ -0,0 +1,316 @@
> +// SPDX-License-Identifier: GPL-2.0
[...]
> +static void vs_drm_device_release_clocks(void *res)
> +{
> +	struct vs_drm_device *priv = res;
> +	unsigned int i;
> +
> +	reset_control_bulk_assert(priv->nrsts, priv->rst_vout);
> +
> +	for (i = 0; i < priv->clk_count; ++i) {
> +		if (priv->clks[i]) {
> +			clk_disable_unprepare(priv->clks[i]);
> +			clk_put(priv->clks[i]);
> +		}
> +	}

Why not use the bulk API for clk as well?

[...]
> +static int vs_drm_device_init_clocks(struct vs_drm_device *priv)
> +{
> +	struct drm_device *dev = &priv->base;
> +	struct platform_device *pdev = to_platform_device(dev->dev);
> +	struct device_node *of_node = pdev->dev.of_node;
> +	struct clk *clock;
> +	unsigned int i;
> +	int ret;
> +
> +	if (dev_get_platdata(&pdev->dev) || !of_node)
> +		return 0;
> +
> +	priv->nrsts = ARRAY_SIZE(priv->rst_vout);
> +	for (int i = 0; i < priv->nrsts; ++i)
> +		priv->rst_vout[i].id = vout_resets[i];
> +	ret = devm_reset_control_bulk_get_shared(dev->dev, priv->nrsts,
> +						 priv->rst_vout);

I would request resets and clocks in _probe().

If component_bind_all() returns -EPROBE_DEFER because of a still
missing DSI panel backlight or similar, this doesn't have to be done
multiple times.

> +	if (ret) {
> +		drm_err(dev, "Failed to get reset controls\n");
> +		return ret;
> +	}
> +
> +	priv->clk_count = of_clk_get_parent_count(of_node);
> +	if (!priv->clk_count)
> +		return 0;
> +
> +	priv->clks = drmm_kzalloc(dev, priv->clk_count * sizeof(priv->clks[0]),
> +				  GFP_KERNEL);
> +	if (!priv->clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < priv->clk_count; ++i) {
> +		clock = of_clk_get(of_node, i);
> +		if (IS_ERR(clock)) {
> +			ret = PTR_ERR(clock);
> +			if (ret == -EPROBE_DEFER)
> +				goto err;
> +			drm_err(dev, "clock %u not found: %d\n", i, ret);
> +			continue;
> +		}
> +		ret = clk_prepare_enable(clock);
> +		if (ret) {
> +			drm_err(dev, "failed to enable clock %u: %d\n",
> +				i, ret);
> +			clk_put(clock);
> +			continue;
> +		}
> +		priv->clks[i] = clock;
> +	}
> +
> +	ret = reset_control_bulk_deassert(priv->nrsts, priv->rst_vout);
> +	if (ret)
> +		return ret;

This should goto err, otherwise clocks are left enabled.

> +
> +	return devm_add_action_or_reset(&pdev->dev,
> +					vs_drm_device_release_clocks,
> +					priv);
> +
> +err:
> +	while (i) {
> +		--i;
> +		if (priv->clks[i]) {
> +			clk_disable_unprepare(priv->clks[i]);
> +			clk_put(priv->clks[i]);
> +		}
> +	}
> +	return ret;
> +}
> +
> +static int vs_drm_bind(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct vs_drm_device *priv;
> +	int ret;
> +	struct drm_device *drm_dev;
> +
> +	/* Remove existing drivers that may own the framebuffer memory. */
> +	ret = drm_aperture_remove_framebuffers(&vs_drm_driver);
> +	if (ret)
> +		return ret;
> +
> +	priv = devm_drm_dev_alloc(dev, &vs_drm_driver, struct vs_drm_device, base);
> +	if (IS_ERR(priv))
> +		return PTR_ERR(priv);
> +
> +	priv->pitch_alignment = 64;

Why is this a variable instead of a constant?

> +	ret = dma_set_coherent_mask(priv->base.dev, DMA_BIT_MASK(40));
> +	if (ret)
> +		return ret;
> +
> +	drm_dev = &priv->base;
> +	platform_set_drvdata(pdev, drm_dev);
> +
> +	ret = vs_drm_device_init_clocks(priv);
> +	if (ret)
> +		return ret;
> +
> +	vs_mode_config_init(drm_dev);
> +
> +	/* Now try and bind all our sub-components */
> +	ret = component_bind_all(dev, drm_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = drm_vblank_init(drm_dev, drm_dev->mode_config.num_crtc);
> +	if (ret)
> +		return ret;

Missing component_unbind_all(), see below.

> +
> +	drm_mode_config_reset(drm_dev);
> +
> +	drm_kms_helper_poll_init(drm_dev);
> +
> +	ret = drm_dev_register(drm_dev, 0);
> +	if (ret)
> +		return ret;

Missing drm_kms_helper_poll_fini(), see below.

> +
> +	drm_fbdev_generic_setup(drm_dev, 32);
> +
> +	return 0;

Here I'd expect an error path calling drm_kms_helper_poll_fini() and
component_unbind_all() as appropriate.


regards
Philipp

Dmitry Baryshkov Dec. 5, 2023, 11:33 a.m. UTC | #2

On Mon, 4 Dec 2023 at 14:33, Keith Zhao <[e-mail]> wrote:
>
> Implement drm device registration interface
>
> Signed-off-by: Keith Zhao <[e-mail]>
> ---
>  MAINTAINERS                              |   1 +
>  drivers/gpu/drm/Kconfig                  |   2 +
>  drivers/gpu/drm/Makefile                 |   1 +
>  drivers/gpu/drm/verisilicon/Kconfig      |  13 +
>  drivers/gpu/drm/verisilicon/Makefile     |   6 +
>  drivers/gpu/drm/verisilicon/vs_drv.c     | 316 +++++++++++++++++++++++
>  drivers/gpu/drm/verisilicon/vs_drv.h     |  42 +++
>  drivers/gpu/drm/verisilicon/vs_modeset.c |  39 +++
>  drivers/gpu/drm/verisilicon/vs_modeset.h |  10 +
>  9 files changed, 430 insertions(+)
>  create mode 100644 drivers/gpu/drm/verisilicon/Kconfig
>  create mode 100644 drivers/gpu/drm/verisilicon/Makefile
>  create mode 100644 drivers/gpu/drm/verisilicon/vs_drv.c
>  create mode 100644 drivers/gpu/drm/verisilicon/vs_drv.h
>  create mode 100644 drivers/gpu/drm/verisilicon/vs_modeset.c
>  create mode 100644 drivers/gpu/drm/verisilicon/vs_modeset.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7caaadb83f3f..8dc9ebfe4605 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6887,6 +6887,7 @@ L:        [e-mail]
>  S:     Maintained
>  T:     git git://anongit.freedesktop.org/drm/drm-misc
>  F:     Documentation/devicetree/bindings/display/starfive/
> +F:     drivers/gpu/drm/verisilicon/
>
>  DRM DRIVER FOR TI DLPC3433 MIPI DSI TO DMD BRIDGE
>  M:     Jagan Teki <[e-mail]>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 3eee8636f847..e8d53c2e7c86 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -394,6 +394,8 @@ source "drivers/gpu/drm/solomon/Kconfig"
>
>  source "drivers/gpu/drm/sprd/Kconfig"
>
> +source "drivers/gpu/drm/verisilicon/Kconfig"
> +
>  config DRM_HYPERV
>         tristate "DRM Support for Hyper-V synthetic video device"
>         depends on DRM && PCI && MMU && HYPERV
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 8e1bde059170..29e04acded06 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -198,3 +198,4 @@ obj-$(CONFIG_DRM_HYPERV) += hyperv/
>  obj-y                  += solomon/
>  obj-$(CONFIG_DRM_SPRD) += sprd/
>  obj-$(CONFIG_DRM_LOONGSON) += loongson/
> +obj-$(CONFIG_DRM_VERISILICON) += verisilicon/
> diff --git a/drivers/gpu/drm/verisilicon/Kconfig b/drivers/gpu/drm/verisilicon/Kconfig
> new file mode 100644
> index 000000000000..e10fa97635aa
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/Kconfig
> @@ -0,0 +1,13 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config DRM_VERISILICON
> +       tristate "DRM Support for VeriSilicon"
> +       depends on DRM
> +       select DRM_KMS_HELPER
> +       select DRM_GEM_DMA_HELPER
> +       select CMA
> +       select DMA_CMA
> +       help
> +         Choose this option if you have a VeriSilicon soc chipset.
> +         This driver provides VeriSilicon kernel mode
> +         setting and buffer management. It does not
> +         provide 2D or 3D acceleration.
> diff --git a/drivers/gpu/drm/verisilicon/Makefile b/drivers/gpu/drm/verisilicon/Makefile
> new file mode 100644
> index 000000000000..d785a1dfaa7f
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +vs_drm-objs := vs_drv.o \
> +              vs_modeset.o
> +
> +obj-$(CONFIG_DRM_VERISILICON) += vs_drm.o
> diff --git a/drivers/gpu/drm/verisilicon/vs_drv.c b/drivers/gpu/drm/verisilicon/vs_drv.c
> new file mode 100644
> index 000000000000..4fb1f29ef84b
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/vs_drv.c
> @@ -0,0 +1,316 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2023 VeriSilicon Holdings Co., Ltd.
> + */
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/of_clk.h>
> +#include <linux/pm_runtime.h>
> +
> +#include <drm/drm_aperture.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_fb_helper.h>
> +#include <drm/drm_fbdev_generic.h>
> +#include <drm/drm_file.h>
> +#include <drm/drm_gem_dma_helper.h>
> +#include <drm/drm_module.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_probe_helper.h>
> +#include <drm/drm_vblank.h>
> +
> +#include "vs_drv.h"
> +#include "vs_modeset.h"
> +
> +#define DRV_NAME       "verisilicon"
> +#define DRV_DESC       "Verisilicon DRM driver"
> +#define DRV_DATE       "20230516"
> +#define DRV_MAJOR      1
> +#define DRV_MINOR      0
> +
> +static int vs_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
> +                             struct drm_mode_create_dumb *args)
> +{
> +       struct vs_drm_device *priv = to_vs_drm_private(dev);
> +       unsigned int pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> +
> +       args->pitch = ALIGN(pitch, priv->pitch_alignment);
> +       return drm_gem_dma_dumb_create_internal(file, dev, args);
> +}
> +
> +DEFINE_DRM_GEM_FOPS(vs_drm_fops);
> +
> +static struct drm_driver vs_drm_driver = {
> +       .driver_features        = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
> +
> +       DRM_GEM_DMA_DRIVER_OPS_WITH_DUMB_CREATE(vs_gem_dumb_create),
> +
> +       .fops                   = &vs_drm_fops,
> +       .name                   = DRV_NAME,
> +       .desc                   = DRV_DESC,
> +       .date                   = DRV_DATE,
> +       .major                  = DRV_MAJOR,
> +       .minor                  = DRV_MINOR,
> +};
> +
> +static void vs_drm_device_release_clocks(void *res)
> +{
> +       struct vs_drm_device *priv = res;
> +       unsigned int i;
> +
> +       reset_control_bulk_assert(priv->nrsts, priv->rst_vout);
> +
> +       for (i = 0; i < priv->clk_count; ++i) {
> +               if (priv->clks[i]) {
> +                       clk_disable_unprepare(priv->clks[i]);
> +                       clk_put(priv->clks[i]);
> +               }
> +       }
> +}
> +
> +static const char * const vout_resets[] = {
> +       "axi",
> +       "ahb",
> +       "core",
> +};
> +
> +static int vs_drm_device_init_clocks(struct vs_drm_device *priv)
> +{
> +       struct drm_device *dev = &priv->base;
> +       struct platform_device *pdev = to_platform_device(dev->dev);
> +       struct device_node *of_node = pdev->dev.of_node;
> +       struct clk *clock;
> +       unsigned int i;
> +       int ret;
> +
> +       if (dev_get_platdata(&pdev->dev) || !of_node)
> +               return 0;

Drop dev_get_platdata(), you don't seem to use it.

> +
> +       priv->nrsts = ARRAY_SIZE(priv->rst_vout);
> +       for (int i = 0; i < priv->nrsts; ++i)
> +               priv->rst_vout[i].id = vout_resets[i];
> +       ret = devm_reset_control_bulk_get_shared(dev->dev, priv->nrsts,
> +                                                priv->rst_vout);
> +       if (ret) {
> +               drm_err(dev, "Failed to get reset controls\n");
> +               return ret;
> +       }
> +
> +       priv->clk_count = of_clk_get_parent_count(of_node);
> +       if (!priv->clk_count)
> +               return 0;
> +
> +       priv->clks = drmm_kzalloc(dev, priv->clk_count * sizeof(priv->clks[0]),
> +                                 GFP_KERNEL);
> +       if (!priv->clks)
> +               return -ENOMEM;
> +
> +       for (i = 0; i < priv->clk_count; ++i) {
> +               clock = of_clk_get(of_node, i);
> +               if (IS_ERR(clock)) {
> +                       ret = PTR_ERR(clock);
> +                       if (ret == -EPROBE_DEFER)
> +                               goto err;
> +                       drm_err(dev, "clock %u not found: %d\n", i, ret);
> +                       continue;
> +               }
> +               ret = clk_prepare_enable(clock);
> +               if (ret) {
> +                       drm_err(dev, "failed to enable clock %u: %d\n",
> +                               i, ret);
> +                       clk_put(clock);
> +                       continue;
> +               }
> +               priv->clks[i] = clock;
> +       }

This can be rewritten as devm_clk_bulk_get_all()

> +
> +       ret = reset_control_bulk_deassert(priv->nrsts, priv->rst_vout);
> +       if (ret)
> +               return ret;

It is a bad idea to mix get_resources kind of function with the actual
resource control. Please move reset deassertion upwards.

> +
> +       return devm_add_action_or_reset(&pdev->dev,
> +                                       vs_drm_device_release_clocks,
> +                                       priv);
> +
> +err:
> +       while (i) {
> +               --i;
> +               if (priv->clks[i]) {
> +                       clk_disable_unprepare(priv->clks[i]);
> +                       clk_put(priv->clks[i]);
> +               }
> +       }
> +       return ret;
> +}
> +
> +static int vs_drm_bind(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct vs_drm_device *priv;
> +       int ret;
> +       struct drm_device *drm_dev;
> +
> +       /* Remove existing drivers that may own the framebuffer memory. */
> +       ret = drm_aperture_remove_framebuffers(&vs_drm_driver);
> +       if (ret)
> +               return ret;

If anything happens during the probe, your platform is left with no
display output. I think it might be better to call this when the
driver has acquired all the resources and is ready to start hw init.

> +
> +       priv = devm_drm_dev_alloc(dev, &vs_drm_driver, struct vs_drm_device, base);
> +       if (IS_ERR(priv))
> +               return PTR_ERR(priv);
> +
> +       priv->pitch_alignment = 64;
> +
> +       ret = dma_set_coherent_mask(priv->base.dev, DMA_BIT_MASK(40));
> +       if (ret)
> +               return ret;
> +
> +       drm_dev = &priv->base;
> +       platform_set_drvdata(pdev, drm_dev);
> +
> +       ret = vs_drm_device_init_clocks(priv);
> +       if (ret)
> +               return ret;
> +
> +       vs_mode_config_init(drm_dev);
> +
> +       /* Now try and bind all our sub-components */
> +       ret = component_bind_all(dev, drm_dev);
> +       if (ret)
> +               return ret;
> +
> +       ret = drm_vblank_init(drm_dev, drm_dev->mode_config.num_crtc);
> +       if (ret)
> +               return ret;
> +
> +       drm_mode_config_reset(drm_dev);
> +
> +       drm_kms_helper_poll_init(drm_dev);
> +
> +       ret = drm_dev_register(drm_dev, 0);
> +       if (ret)
> +               return ret;

Teardown path is missing.

> +
> +       drm_fbdev_generic_setup(drm_dev, 32);
> +
> +       return 0;
> +}
> +
> +static void vs_drm_unbind(struct device *dev)
> +{
> +       struct drm_device *drm_dev = dev_get_drvdata(dev);
> +
> +       drm_dev_unregister(drm_dev);
> +       drm_kms_helper_poll_fini(drm_dev);
> +       component_unbind_all(drm_dev->dev, drm_dev);
> +}
> +
> +static const struct component_master_ops vs_drm_ops = {
> +       .bind = vs_drm_bind,
> +       .unbind = vs_drm_unbind,
> +};
> +
> +static struct platform_driver *drm_sub_drivers[] = {
> +};
> +
> +static struct component_match *vs_drm_match_add(struct device *dev)
> +{
> +       struct component_match *match = NULL;
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(drm_sub_drivers); ++i) {
> +               struct platform_driver *drv = drm_sub_drivers[i];
> +               struct device *p = NULL, *d;
> +
> +               while ((d = platform_find_device_by_driver(p, &drv->driver))) {
> +                       put_device(p);
> +
> +                       drm_of_component_match_add(dev, &match, component_compare_of,
> +                                                  d->of_node);
> +                       p = d;
> +               }
> +               put_device(p);
> +       }
> +
> +       return match ? match : ERR_PTR(-ENODEV);
> +}
> +
> +static int vs_drm_platform_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct component_match *match;
> +
> +       match = vs_drm_match_add(dev);
> +       if (IS_ERR(match))
> +               return PTR_ERR(match);
> +
> +       return component_master_add_with_match(dev, &vs_drm_ops, match);

I wonder if you can use drm_of_component_probe() instead?

> +}
> +
> +static int vs_drm_platform_remove(struct platform_device *pdev)

I think this should be void vs_drm_platform_remove() and .remove_new

> +{
> +       component_master_del(&pdev->dev, &vs_drm_ops);
> +       return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int vs_drm_suspend(struct device *dev)
> +{
> +       return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
> +}
> +
> +static int vs_drm_resume(struct device *dev)
> +{
> +       drm_mode_config_helper_resume(dev_get_drvdata(dev));

return drm_mode_config_helper_resume()

> +
> +       return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(vs_drm_pm_ops, vs_drm_suspend, vs_drm_resume);
> +
> +static const struct of_device_id vs_drm_dt_ids[] = {
> +       { .compatible = "starfive,display-subsystem", },
> +       { },
> +};
> +
> +MODULE_DEVICE_TABLE(of, vs_drm_dt_ids);
> +
> +static struct platform_driver vs_drm_platform_driver = {
> +       .probe = vs_drm_platform_probe,
> +       .remove = vs_drm_platform_remove,
> +
> +       .driver = {
> +               .name = DRV_NAME,
> +               .of_match_table = vs_drm_dt_ids,
> +               .pm = &vs_drm_pm_ops,
> +       },
> +};
> +
> +static int __init vs_drm_init(void)
> +{
> +       int ret;
> +
> +       ret = platform_register_drivers(drm_sub_drivers, ARRAY_SIZE(drm_sub_drivers));
> +       if (ret)
> +               return ret;
> +
> +       ret = drm_platform_driver_register(&vs_drm_platform_driver);
> +       if (ret)
> +               platform_unregister_drivers(drm_sub_drivers, ARRAY_SIZE(drm_sub_drivers));
> +
> +       return ret;
> +}
> +
> +static void __exit vs_drm_fini(void)
> +{
> +       platform_driver_unregister(&vs_drm_platform_driver);
> +       platform_unregister_drivers(drm_sub_drivers, ARRAY_SIZE(drm_sub_drivers));
> +}
> +
> +late_initcall_sync(vs_drm_init);
> +module_exit(vs_drm_fini);
> +
> +MODULE_DESCRIPTION("VeriSilicon DRM Driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/gpu/drm/verisilicon/vs_drv.h b/drivers/gpu/drm/verisilicon/vs_drv.h
> new file mode 100644
> index 000000000000..ea2189772980
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/vs_drv.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2023 VeriSilicon Holdings Co., Ltd.
> + */
> +
> +#ifndef __VS_DRV_H__
> +#define __VS_DRV_H__
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_gem.h>
> +#include <drm/drm_managed.h>
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +
> +enum rst_vout {
> +       RST_VOUT_AXI = 0,
> +       RST_VOUT_AHB,
> +       RST_VOUT_CORE,
> +       RST_VOUT_NUM
> +};

Do you need these values? They can easily get out of sync with vout_rsts.

> +
> +/*@pitch_alignment: buffer pitch alignment required by sub-devices.*/
> +struct vs_drm_device {
> +       struct drm_device base;
> +       unsigned int pitch_alignment;
> +       /* clocks */
> +       unsigned int clk_count;
> +       struct clk **clks;
> +
> +       struct reset_control_bulk_data rst_vout[RST_VOUT_NUM];
> +       int     nrsts;
> +};
> +
> +static inline struct vs_drm_device *
> +to_vs_drm_private(const struct drm_device *dev)
> +{
> +       return container_of(dev, struct vs_drm_device, base);
> +}
> +
> +#endif /* __VS_DRV_H__ */
> diff --git a/drivers/gpu/drm/verisilicon/vs_modeset.c b/drivers/gpu/drm/verisilicon/vs_modeset.c
> new file mode 100644
> index 000000000000..eaf406c1b7c7
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/vs_modeset.c
> @@ -0,0 +1,39 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2023 VeriSilicon Holdings Co., Ltd.
> + */
> +
> +#include <linux/module.h>
> +
> +#include <drm/drm_damage_helper.h>
> +#include <drm/drm_fb_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
> +
> +#include "vs_modeset.h"
> +
> +static const struct drm_mode_config_funcs vs_mode_config_funcs = {
> +       .fb_create                       = drm_gem_fb_create,
> +       .atomic_check            = drm_atomic_helper_check,
> +       .atomic_commit           = drm_atomic_helper_commit,
> +};
> +
> +static struct drm_mode_config_helper_funcs vs_mode_config_helpers = {
> +       .atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
> +};
> +
> +void vs_mode_config_init(struct drm_device *dev)
> +{
> +       int ret;
> +
> +       ret = drmm_mode_config_init(dev);
> +       if (ret)
> +               return;
> +
> +       dev->mode_config.min_width  = 0;
> +       dev->mode_config.min_height = 0;
> +       dev->mode_config.max_width  = 4096;
> +       dev->mode_config.max_height = 4096;
> +
> +       dev->mode_config.funcs = &vs_mode_config_funcs;
> +       dev->mode_config.helper_private = &vs_mode_config_helpers;
> +}
> diff --git a/drivers/gpu/drm/verisilicon/vs_modeset.h b/drivers/gpu/drm/verisilicon/vs_modeset.h
> new file mode 100644
> index 000000000000..bd04f81d2ad2
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/vs_modeset.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020 VeriSilicon Holdings Co., Ltd.
> + */
> +
> +#ifndef __VS_MODESET_H__
> +#define __VS_MODESET_H__
> +
> +void vs_mode_config_init(struct drm_device *dev);
> +#endif /* __VS_FB_H__ */
> --
> 2.34.1
>

Keith Zhao Dec. 11, 2023, 9 a.m. UTC | #3

hi Philipp:

On 2023/12/4 21:30, Philipp Zabel wrote:
> Hi Keith,
> 
> On Mo, 2023-12-04 at 20:33 +0800, Keith Zhao wrote:
>> Implement drm device registration interface
>> 
>> Signed-off-by: Keith Zhao <[e-mail]>
>> ---
> [...]
>> diff --git a/drivers/gpu/drm/verisilicon/Kconfig b/drivers/gpu/drm/verisilicon/Kconfig
>> new file mode 100644
>> index 000000000000..e10fa97635aa
>> --- /dev/null
>> +++ b/drivers/gpu/drm/verisilicon/Kconfig
>> @@ -0,0 +1,13 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +config DRM_VERISILICON
>> +	tristate "DRM Support for VeriSilicon"
>> +	depends on DRM
>> +	select DRM_KMS_HELPER
>> +	select DRM_GEM_DMA_HELPER
>> +	select CMA
>> +	select DMA_CMA
>> +	help
>> +	  Choose this option if you have a VeriSilicon soc chipset.
> 
> This seems a bit generic. Doesn't the VeriSilicon display controller IP
> used on JH7110 have a product name?
yes , there is a product name "dc8200", I will match it.
> 
> [...]
>> diff --git a/drivers/gpu/drm/verisilicon/vs_drv.c b/drivers/gpu/drm/verisilicon/vs_drv.c
>> new file mode 100644
>> index 000000000000..4fb1f29ef84b
>> --- /dev/null
>> +++ b/drivers/gpu/drm/verisilicon/vs_drv.c
>> @@ -0,0 +1,316 @@
>> +// SPDX-License-Identifier: GPL-2.0
> [...]
>> +static void vs_drm_device_release_clocks(void *res)
>> +{
>> +	struct vs_drm_device *priv = res;
>> +	unsigned int i;
>> +
>> +	reset_control_bulk_assert(priv->nrsts, priv->rst_vout);
>> +
>> +	for (i = 0; i < priv->clk_count; ++i) {
>> +		if (priv->clks[i]) {
>> +			clk_disable_unprepare(priv->clks[i]);
>> +			clk_put(priv->clks[i]);
>> +		}
>> +	}
> 
> Why not use the bulk API for clk as well?
ok , will do it next version
> 
> [...]
>> +static int vs_drm_device_init_clocks(struct vs_drm_device *priv)
>> +{
>> +	struct drm_device *dev = &priv->base;
>> +	struct platform_device *pdev = to_platform_device(dev->dev);
>> +	struct device_node *of_node = pdev->dev.of_node;
>> +	struct clk *clock;
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	if (dev_get_platdata(&pdev->dev) || !of_node)
>> +		return 0;
>> +
>> +	priv->nrsts = ARRAY_SIZE(priv->rst_vout);
>> +	for (int i = 0; i < priv->nrsts; ++i)
>> +		priv->rst_vout[i].id = vout_resets[i];
>> +	ret = devm_reset_control_bulk_get_shared(dev->dev, priv->nrsts,
>> +						 priv->rst_vout);
> 
> I would request resets and clocks in _probe().

> 
> If component_bind_all() returns -EPROBE_DEFER because of a still
> missing DSI panel backlight or similar, this doesn't have to be done
> multiple times.
I got what you mean. component_bind_all should be done multiple times
 to prevent the dsi panel driver from lagging load.

in my drm subsystem , there are 2 pipeline 

          +------------------------------+
          |                              |
          |                              |
  +----+  |   +-------------------+      |   +-------+   +------+   +------+
  |    +----->+  dc controller 0  +--->----->+HDMICtl| ->+ PHY  +-->+PANEL0+
  |AXI |  |   +-------------------+      |   +-------+   +------+   +------+
  |    |  |                              |
  |    |  |                              |
  |    |  |                              |
  |    |  |                              |
  |APB |  |   +-------------------+         +---------+    +------+  +-------+
  |    +----->+  dc controller 1  +--->---->+ dsiTx   +--->+DPHY  +->+ PANEL1+
  |    |  |   +-------------------+         +---------+    +------+  +-------+
  +----+  |                              |
          +------------------------------+


component_bind_all will bind the hdmi encoder and dsi encoder .
binding the hdmi encoder will always return ok .

binging the dsi encoder has a question :
I used the panel-raspberrypi-touchscreen.c as panel driver , 
this driver is a i2c device and it use a i2c command to read reg ID
if read success , it will do drm_panel_add. 

if I disconnect the panel ,it will not do drm_panel_add.
dsiTx will fail to find panel , The consequence is that the inputbridge cannot be created , 
also outputbridge cannot be created.
for encoder bind , it will fail to find the input bridge of dsi.
Under this premise, although returning -EPROBE_DEFER allows bind to be executed multiple times, 
the final result is that the entire bind fails.

returning -EPROBE_DEFER can solve panel driver from lagging load , 
but for no panel case , it will destory all pipeline (include hdmi and dsi).

I did two things:
late_initcall_sync(vs_drm_init); to make sure the panel drive has been probed;
dsi encoder bind always return ok to make sure hdmi pipeline ok at lease.
component_bind_all do once . 




> 
>> +	if (ret) {
>> +		drm_err(dev, "Failed to get reset controls\n");
>> +		return ret;
>> +	}
>> +
>> +	priv->clk_count = of_clk_get_parent_count(of_node);
>> +	if (!priv->clk_count)
>> +		return 0;
>> +
>> +	priv->clks = drmm_kzalloc(dev, priv->clk_count * sizeof(priv->clks[0]),
>> +				  GFP_KERNEL);
>> +	if (!priv->clks)
>> +		return -ENOMEM;
>> +
>> +	for (i = 0; i < priv->clk_count; ++i) {
>> +		clock = of_clk_get(of_node, i);
>> +		if (IS_ERR(clock)) {
>> +			ret = PTR_ERR(clock);
>> +			if (ret == -EPROBE_DEFER)
>> +				goto err;
>> +			drm_err(dev, "clock %u not found: %d\n", i, ret);
>> +			continue;
>> +		}
>> +		ret = clk_prepare_enable(clock);
>> +		if (ret) {
>> +			drm_err(dev, "failed to enable clock %u: %d\n",
>> +				i, ret);
>> +			clk_put(clock);
>> +			continue;
>> +		}
>> +		priv->clks[i] = clock;
>> +	}
>> +
>> +	ret = reset_control_bulk_deassert(priv->nrsts, priv->rst_vout);
>> +	if (ret)
>> +		return ret;
> 
> This should goto err, otherwise clocks are left enabled.
> 
>> +
>> +	return devm_add_action_or_reset(&pdev->dev,
>> +					vs_drm_device_release_clocks,
>> +					priv);
>> +
>> +err:
>> +	while (i) {
>> +		--i;
>> +		if (priv->clks[i]) {
>> +			clk_disable_unprepare(priv->clks[i]);
>> +			clk_put(priv->clks[i]);
>> +		}
>> +	}
>> +	return ret;
>> +}
>> +
>> +static int vs_drm_bind(struct device *dev)
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct vs_drm_device *priv;
>> +	int ret;
>> +	struct drm_device *drm_dev;
>> +
>> +	/* Remove existing drivers that may own the framebuffer memory. */
>> +	ret = drm_aperture_remove_framebuffers(&vs_drm_driver);
>> +	if (ret)
>> +		return ret;
>> +
>> +	priv = devm_drm_dev_alloc(dev, &vs_drm_driver, struct vs_drm_device, base);
>> +	if (IS_ERR(priv))
>> +		return PTR_ERR(priv);
>> +
>> +	priv->pitch_alignment = 64;
> 
> Why is this a variable instead of a constant?
the dc controllers of VeriSilicon have different series, like dc8200 , dc9200...
Their pitch values may vary from series to series, like 64 , 128

> 
>> +	ret = dma_set_coherent_mask(priv->base.dev, DMA_BIT_MASK(40));
>> +	if (ret)
>> +		return ret;
>> +
>> +	drm_dev = &priv->base;
>> +	platform_set_drvdata(pdev, drm_dev);
>> +
>> +	ret = vs_drm_device_init_clocks(priv);
>> +	if (ret)
>> +		return ret;
>> +
>> +	vs_mode_config_init(drm_dev);
>> +
>> +	/* Now try and bind all our sub-components */
>> +	ret = component_bind_all(dev, drm_dev);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = drm_vblank_init(drm_dev, drm_dev->mode_config.num_crtc);
>> +	if (ret)
>> +		return ret;
> 
> Missing component_unbind_all(), see below.
> 
>> +
>> +	drm_mode_config_reset(drm_dev);
>> +
>> +	drm_kms_helper_poll_init(drm_dev);
>> +
>> +	ret = drm_dev_register(drm_dev, 0);
>> +	if (ret)
>> +		return ret;
> 
> Missing drm_kms_helper_poll_fini(), see below.
> 
>> +
>> +	drm_fbdev_generic_setup(drm_dev, 32);
>> +
>> +	return 0;
> 
> Here I'd expect an error path calling drm_kms_helper_poll_fini() and
> component_unbind_all() as appropriate.
> 
ok

> 
> regards
> Philipp

[e-mail] Dec. 11, 2023, 9:17 a.m. UTC | #4

Hi,

On Mon, Dec 11, 2023 at 05:00:04PM +0800, Keith Zhao wrote:
> >> +static int vs_drm_device_init_clocks(struct vs_drm_device *priv)
> >> +{
> >> +	struct drm_device *dev = &priv->base;
> >> +	struct platform_device *pdev = to_platform_device(dev->dev);
> >> +	struct device_node *of_node = pdev->dev.of_node;
> >> +	struct clk *clock;
> >> +	unsigned int i;
> >> +	int ret;
> >> +
> >> +	if (dev_get_platdata(&pdev->dev) || !of_node)
> >> +		return 0;
> >> +
> >> +	priv->nrsts = ARRAY_SIZE(priv->rst_vout);
> >> +	for (int i = 0; i < priv->nrsts; ++i)
> >> +		priv->rst_vout[i].id = vout_resets[i];
> >> +	ret = devm_reset_control_bulk_get_shared(dev->dev, priv->nrsts,
> >> +						 priv->rst_vout);
> > 
> > I would request resets and clocks in _probe().
> 
> > 
> > If component_bind_all() returns -EPROBE_DEFER because of a still
> > missing DSI panel backlight or similar, this doesn't have to be done
> > multiple times.
> I got what you mean. component_bind_all should be done multiple times
>  to prevent the dsi panel driver from lagging load.

No. component_bind_all only needs to be called once.

> in my drm subsystem , there are 2 pipeline 
> 
>           +------------------------------+
>           |                              |
>           |                              |
>   +----+  |   +-------------------+      |   +-------+   +------+   +------+
>   |    +----->+  dc controller 0  +--->----->+HDMICtl| ->+ PHY  +-->+PANEL0+
>   |AXI |  |   +-------------------+      |   +-------+   +------+   +------+
>   |    |  |                              |
>   |    |  |                              |
>   |    |  |                              |
>   |    |  |                              |
>   |APB |  |   +-------------------+         +---------+    +------+  +-------+
>   |    +----->+  dc controller 1  +--->---->+ dsiTx   +--->+DPHY  +->+ PANEL1+
>   |    |  |   +-------------------+         +---------+    +------+  +-------+
>   +----+  |                              |
>           +------------------------------+
> 
> 
> component_bind_all will bind the hdmi encoder and dsi encoder .
> binding the hdmi encoder will always return ok .
> 
> binging the dsi encoder has a question :
> I used the panel-raspberrypi-touchscreen.c as panel driver , 
> this driver is a i2c device and it use a i2c command to read reg ID
> if read success , it will do drm_panel_add. 
> 
> if I disconnect the panel ,it will not do drm_panel_add.
> dsiTx will fail to find panel , The consequence is that the inputbridge cannot be created , 
> also outputbridge cannot be created.
> for encoder bind , it will fail to find the input bridge of dsi.
> Under this premise, although returning -EPROBE_DEFER allows bind to be executed multiple times, 
> the final result is that the entire bind fails.
> 
> returning -EPROBE_DEFER can solve panel driver from lagging load , 
> but for no panel case , it will destory all pipeline (include hdmi and dsi).

Yes, that's expected.

> I did two things:
> late_initcall_sync(vs_drm_init); to make sure the panel drive has been probed;
> dsi encoder bind always return ok to make sure hdmi pipeline ok at lease.
> component_bind_all do once . 

You should have a look at
https://www.kernel.org/doc/html/latest/gpu/drm-kms-helpers.html#special-care-with-mipi-dsi-bridges

Maxime

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 7caaadb83f3f..8dc9ebfe4605 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6887,6 +6887,7 @@  L:	[e-mail]
 S:	Maintained
 T:	git git://anongit.freedesktop.org/drm/drm-misc
 F:	Documentation/devicetree/bindings/display/starfive/
+F:	drivers/gpu/drm/verisilicon/
 
 DRM DRIVER FOR TI DLPC3433 MIPI DSI TO DMD BRIDGE
 M:	Jagan Teki <[e-mail]>
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 3eee8636f847..e8d53c2e7c86 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -394,6 +394,8 @@  source "drivers/gpu/drm/solomon/Kconfig"
 
 source "drivers/gpu/drm/sprd/Kconfig"
 
+source "drivers/gpu/drm/verisilicon/Kconfig"
+
 config DRM_HYPERV
 	tristate "DRM Support for Hyper-V synthetic video device"
 	depends on DRM && PCI && MMU && HYPERV
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 8e1bde059170..29e04acded06 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -198,3 +198,4 @@  obj-$(CONFIG_DRM_HYPERV) += hyperv/
 obj-y			+= solomon/
 obj-$(CONFIG_DRM_SPRD) += sprd/
 obj-$(CONFIG_DRM_LOONGSON) += loongson/
+obj-$(CONFIG_DRM_VERISILICON) += verisilicon/
diff --git a/drivers/gpu/drm/verisilicon/Kconfig b/drivers/gpu/drm/verisilicon/Kconfig
new file mode 100644
index 000000000000..e10fa97635aa
--- /dev/null
+++ b/drivers/gpu/drm/verisilicon/Kconfig
@@ -0,0 +1,13 @@ 
+# SPDX-License-Identifier: GPL-2.0
+config DRM_VERISILICON
+	tristate "DRM Support for VeriSilicon"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_GEM_DMA_HELPER
+	select CMA
+	select DMA_CMA
+	help
+	  Choose this option if you have a VeriSilicon soc chipset.
+	  This driver provides VeriSilicon kernel mode
+	  setting and buffer management. It does not
+	  provide 2D or 3D acceleration.
diff --git a/drivers/gpu/drm/verisilicon/Makefile b/drivers/gpu/drm/verisilicon/Makefile
new file mode 100644
index 000000000000..d785a1dfaa7f
--- /dev/null
+++ b/drivers/gpu/drm/verisilicon/Makefile
@@ -0,0 +1,6 @@ 
+# SPDX-License-Identifier: GPL-2.0
+
+vs_drm-objs := vs_drv.o \
+	       vs_modeset.o
+
+obj-$(CONFIG_DRM_VERISILICON) += vs_drm.o
diff --git a/drivers/gpu/drm/verisilicon/vs_drv.c b/drivers/gpu/drm/verisilicon/vs_drv.c
new file mode 100644
index 000000000000..4fb1f29ef84b
--- /dev/null
+++ b/drivers/gpu/drm/verisilicon/vs_drv.c
@@ -0,0 +1,316 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 VeriSilicon Holdings Co., Ltd.
+ */
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/of_clk.h>
+#include <linux/pm_runtime.h>
+
+#include <drm/drm_aperture.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_fbdev_generic.h>
+#include <drm/drm_file.h>
+#include <drm/drm_gem_dma_helper.h>
+#include <drm/drm_module.h>
+#include <drm/drm_of.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_vblank.h>
+
+#include "vs_drv.h"
+#include "vs_modeset.h"
+
+#define DRV_NAME	"verisilicon"
+#define DRV_DESC	"Verisilicon DRM driver"
+#define DRV_DATE	"20230516"
+#define DRV_MAJOR	1
+#define DRV_MINOR	0
+
+static int vs_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
+			      struct drm_mode_create_dumb *args)
+{
+	struct vs_drm_device *priv = to_vs_drm_private(dev);
+	unsigned int pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+
+	args->pitch = ALIGN(pitch, priv->pitch_alignment);
+	return drm_gem_dma_dumb_create_internal(file, dev, args);
+}
+
+DEFINE_DRM_GEM_FOPS(vs_drm_fops);
+
+static struct drm_driver vs_drm_driver = {
+	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
+
+	DRM_GEM_DMA_DRIVER_OPS_WITH_DUMB_CREATE(vs_gem_dumb_create),
+
+	.fops			= &vs_drm_fops,
+	.name			= DRV_NAME,
+	.desc			= DRV_DESC,
+	.date			= DRV_DATE,
+	.major			= DRV_MAJOR,
+	.minor			= DRV_MINOR,
+};
+
+static void vs_drm_device_release_clocks(void *res)
+{
+	struct vs_drm_device *priv = res;
+	unsigned int i;
+
+	reset_control_bulk_assert(priv->nrsts, priv->rst_vout);
+
+	for (i = 0; i < priv->clk_count; ++i) {
+		if (priv->clks[i]) {
+			clk_disable_unprepare(priv->clks[i]);
+			clk_put(priv->clks[i]);
+		}
+	}
+}
+
+static const char * const vout_resets[] = {
+	"axi",
+	"ahb",
+	"core",
+};
+
+static int vs_drm_device_init_clocks(struct vs_drm_device *priv)
+{
+	struct drm_device *dev = &priv->base;
+	struct platform_device *pdev = to_platform_device(dev->dev);
+	struct device_node *of_node = pdev->dev.of_node;
+	struct clk *clock;
+	unsigned int i;
+	int ret;
+
+	if (dev_get_platdata(&pdev->dev) || !of_node)
+		return 0;
+
+	priv->nrsts = ARRAY_SIZE(priv->rst_vout);
+	for (int i = 0; i < priv->nrsts; ++i)
+		priv->rst_vout[i].id = vout_resets[i];
+	ret = devm_reset_control_bulk_get_shared(dev->dev, priv->nrsts,
+						 priv->rst_vout);
+	if (ret) {
+		drm_err(dev, "Failed to get reset controls\n");
+		return ret;
+	}
+
+	priv->clk_count = of_clk_get_parent_count(of_node);
+	if (!priv->clk_count)
+		return 0;
+
+	priv->clks = drmm_kzalloc(dev, priv->clk_count * sizeof(priv->clks[0]),
+				  GFP_KERNEL);
+	if (!priv->clks)
+		return -ENOMEM;
+
+	for (i = 0; i < priv->clk_count; ++i) {
+		clock = of_clk_get(of_node, i);
+		if (IS_ERR(clock)) {
+			ret = PTR_ERR(clock);
+			if (ret == -EPROBE_DEFER)
+				goto err;
+			drm_err(dev, "clock %u not found: %d\n", i, ret);
+			continue;
+		}
+		ret = clk_prepare_enable(clock);
+		if (ret) {
+			drm_err(dev, "failed to enable clock %u: %d\n",
+				i, ret);
+			clk_put(clock);
+			continue;
+		}
+		priv->clks[i] = clock;
+	}
+
+	ret = reset_control_bulk_deassert(priv->nrsts, priv->rst_vout);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(&pdev->dev,
+					vs_drm_device_release_clocks,
+					priv);
+
+err:
+	while (i) {
+		--i;
+		if (priv->clks[i]) {
+			clk_disable_unprepare(priv->clks[i]);
+			clk_put(priv->clks[i]);
+		}
+	}
+	return ret;
+}
+
+static int vs_drm_bind(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct vs_drm_device *priv;
+	int ret;
+	struct drm_device *drm_dev;
+
+	/* Remove existing drivers that may own the framebuffer memory. */
+	ret = drm_aperture_remove_framebuffers(&vs_drm_driver);
+	if (ret)
+		return ret;
+
+	priv = devm_drm_dev_alloc(dev, &vs_drm_driver, struct vs_drm_device, base);
+	if (IS_ERR(priv))
+		return PTR_ERR(priv);
+
+	priv->pitch_alignment = 64;
+
+	ret = dma_set_coherent_mask(priv->base.dev, DMA_BIT_MASK(40));
+	if (ret)
+		return ret;
+
+	drm_dev = &priv->base;
+	platform_set_drvdata(pdev, drm_dev);
+
+	ret = vs_drm_device_init_clocks(priv);
+	if (ret)
+		return ret;
+
+	vs_mode_config_init(drm_dev);
+
+	/* Now try and bind all our sub-components */
+	ret = component_bind_all(dev, drm_dev);
+	if (ret)
+		return ret;
+
+	ret = drm_vblank_init(drm_dev, drm_dev->mode_config.num_crtc);
+	if (ret)
+		return ret;
+
+	drm_mode_config_reset(drm_dev);
+
+	drm_kms_helper_poll_init(drm_dev);
+
+	ret = drm_dev_register(drm_dev, 0);
+	if (ret)
+		return ret;
+
+	drm_fbdev_generic_setup(drm_dev, 32);
+
+	return 0;
+}
+
+static void vs_drm_unbind(struct device *dev)
+{
+	struct drm_device *drm_dev = dev_get_drvdata(dev);
+
+	drm_dev_unregister(drm_dev);
+	drm_kms_helper_poll_fini(drm_dev);
+	component_unbind_all(drm_dev->dev, drm_dev);
+}
+
+static const struct component_master_ops vs_drm_ops = {
+	.bind = vs_drm_bind,
+	.unbind = vs_drm_unbind,
+};
+
+static struct platform_driver *drm_sub_drivers[] = {
+};
+
+static struct component_match *vs_drm_match_add(struct device *dev)
+{
+	struct component_match *match = NULL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(drm_sub_drivers); ++i) {
+		struct platform_driver *drv = drm_sub_drivers[i];
+		struct device *p = NULL, *d;
+
+		while ((d = platform_find_device_by_driver(p, &drv->driver))) {
+			put_device(p);
+
+			drm_of_component_match_add(dev, &match, component_compare_of,
+						   d->of_node);
+			p = d;
+		}
+		put_device(p);
+	}
+
+	return match ? match : ERR_PTR(-ENODEV);
+}
+
+static int vs_drm_platform_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct component_match *match;
+
+	match = vs_drm_match_add(dev);
+	if (IS_ERR(match))
+		return PTR_ERR(match);
+
+	return component_master_add_with_match(dev, &vs_drm_ops, match);
+}
+
+static int vs_drm_platform_remove(struct platform_device *pdev)
+{
+	component_master_del(&pdev->dev, &vs_drm_ops);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int vs_drm_suspend(struct device *dev)
+{
+	return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
+}
+
+static int vs_drm_resume(struct device *dev)
+{
+	drm_mode_config_helper_resume(dev_get_drvdata(dev));
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(vs_drm_pm_ops, vs_drm_suspend, vs_drm_resume);
+
+static const struct of_device_id vs_drm_dt_ids[] = {
+	{ .compatible = "starfive,display-subsystem", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, vs_drm_dt_ids);
+
+static struct platform_driver vs_drm_platform_driver = {
+	.probe = vs_drm_platform_probe,
+	.remove = vs_drm_platform_remove,
+
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table = vs_drm_dt_ids,
+		.pm = &vs_drm_pm_ops,
+	},
+};
+
+static int __init vs_drm_init(void)
+{
+	int ret;
+
+	ret = platform_register_drivers(drm_sub_drivers, ARRAY_SIZE(drm_sub_drivers));
+	if (ret)
+		return ret;
+
+	ret = drm_platform_driver_register(&vs_drm_platform_driver);
+	if (ret)
+		platform_unregister_drivers(drm_sub_drivers, ARRAY_SIZE(drm_sub_drivers));
+
+	return ret;
+}
+
+static void __exit vs_drm_fini(void)
+{
+	platform_driver_unregister(&vs_drm_platform_driver);
+	platform_unregister_drivers(drm_sub_drivers, ARRAY_SIZE(drm_sub_drivers));
+}
+
+late_initcall_sync(vs_drm_init);
+module_exit(vs_drm_fini);
+
+MODULE_DESCRIPTION("VeriSilicon DRM Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/verisilicon/vs_drv.h b/drivers/gpu/drm/verisilicon/vs_drv.h
new file mode 100644
index 000000000000..ea2189772980
--- /dev/null
+++ b/drivers/gpu/drm/verisilicon/vs_drv.h
@@ -0,0 +1,42 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 VeriSilicon Holdings Co., Ltd.
+ */
+
+#ifndef __VS_DRV_H__
+#define __VS_DRV_H__
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_gem.h>
+#include <drm/drm_managed.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+
+enum rst_vout {
+	RST_VOUT_AXI = 0,
+	RST_VOUT_AHB,
+	RST_VOUT_CORE,
+	RST_VOUT_NUM
+};
+
+/*@pitch_alignment: buffer pitch alignment required by sub-devices.*/
+struct vs_drm_device {
+	struct drm_device base;
+	unsigned int pitch_alignment;
+	/* clocks */
+	unsigned int clk_count;
+	struct clk **clks;
+
+	struct reset_control_bulk_data rst_vout[RST_VOUT_NUM];
+	int	nrsts;
+};
+
+static inline struct vs_drm_device *
+to_vs_drm_private(const struct drm_device *dev)
+{
+	return container_of(dev, struct vs_drm_device, base);
+}
+
+#endif /* __VS_DRV_H__ */
diff --git a/drivers/gpu/drm/verisilicon/vs_modeset.c b/drivers/gpu/drm/verisilicon/vs_modeset.c
new file mode 100644
index 000000000000..eaf406c1b7c7
--- /dev/null
+++ b/drivers/gpu/drm/verisilicon/vs_modeset.c
@@ -0,0 +1,39 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 VeriSilicon Holdings Co., Ltd.
+ */
+
+#include <linux/module.h>
+
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+
+#include "vs_modeset.h"
+
+static const struct drm_mode_config_funcs vs_mode_config_funcs = {
+	.fb_create			 = drm_gem_fb_create,
+	.atomic_check		 = drm_atomic_helper_check,
+	.atomic_commit		 = drm_atomic_helper_commit,
+};
+
+static struct drm_mode_config_helper_funcs vs_mode_config_helpers = {
+	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
+};
+
+void vs_mode_config_init(struct drm_device *dev)
+{
+	int ret;
+
+	ret = drmm_mode_config_init(dev);
+	if (ret)
+		return;
+
+	dev->mode_config.min_width  = 0;
+	dev->mode_config.min_height = 0;
+	dev->mode_config.max_width  = 4096;
+	dev->mode_config.max_height = 4096;
+
+	dev->mode_config.funcs = &vs_mode_config_funcs;
+	dev->mode_config.helper_private = &vs_mode_config_helpers;
+}
diff --git a/drivers/gpu/drm/verisilicon/vs_modeset.h b/drivers/gpu/drm/verisilicon/vs_modeset.h
new file mode 100644
index 000000000000..bd04f81d2ad2
--- /dev/null
+++ b/drivers/gpu/drm/verisilicon/vs_modeset.h
@@ -0,0 +1,10 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 VeriSilicon Holdings Co., Ltd.
+ */
+
+#ifndef __VS_MODESET_H__
+#define __VS_MODESET_H__
+
+void vs_mode_config_init(struct drm_device *dev);
+#endif /* __VS_FB_H__ */