diff mbox series

[PATCHv5,02/34] drm/gem-fb-helper: Allow drivers to allocate struct drm_framebuffer on their own

Message ID 20191217145020.14645-3-andrzej.p@collabora.com (mailing list archive)
State New, archived
Headers show
Series Add AFBC support for Rockchip | expand

Commit Message

Andrzej Pietrasiewicz Dec. 17, 2019, 2:49 p.m. UTC 
Prepare tools for drivers which need to allocate a struct drm_framebuffer
(or a container of struct drm_framebuffer) explicitly, before calling
helpers. In such a case we need new helpers which omit allocating the
struct drm_framebuffer and this patch provides them. Consequently, they
are used also inside the helpers themselves.

The interested drivers will likely need to be able to perform object
lookups and size checks in separate invocations and this patch provides
that as well. Helpers themselves are updated, too.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
---
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 216 ++++++++++++++-----
 include/drm/drm_gem_framebuffer_helper.h     |  17 ++
 2 files changed, 181 insertions(+), 52 deletions(-)

Comments

James Qian Wang Feb. 18, 2020, 3:34 a.m. UTC | #1 
Hi Andrzej:
On Tue, Dec 17, 2019 at 03:49:48PM +0100, Andrzej Pietrasiewicz wrote:
> Prepare tools for drivers which need to allocate a struct drm_framebuffer
> (or a container of struct drm_framebuffer) explicitly, before calling
> helpers. In such a case we need new helpers which omit allocating the
> struct drm_framebuffer and this patch provides them. Consequently, they
> are used also inside the helpers themselves.
> 
> The interested drivers will likely need to be able to perform object
> lookups and size checks in separate invocations and this patch provides
> that as well. Helpers themselves are updated, too.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>  drivers/gpu/drm/drm_gem_framebuffer_helper.c | 216 ++++++++++++++-----
>  include/drm/drm_gem_framebuffer_helper.h     |  17 ++
>  2 files changed, 181 insertions(+), 52 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> index b9bcd310ca2d..b3494f6b66bb 100644
> --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> @@ -54,6 +54,69 @@ struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
>  
> +/**
> + * drm_gem_fb_init_with_funcs() - Initialize an already allocated framebuffer
> + * @fb: Framebuffer
> + * @dev: DRM device
> + * @mode_cmd: Metadata from the userspace framebuffer creation request
> + * @obj: GEM objects to be assigned to the framebuffer
> + * @num_planes: number of planes
> + * @funcs: vtable to be used for the framebuffer object
> + *
> + * This variant of the function allows passing a custom vtable.
> + *
> + * Returns:
> + * 0 on success or a negative error code
> + */
> +int drm_gem_fb_init_with_funcs(struct drm_framebuffer *fb,
> +			       struct drm_device *dev,
> +			       const struct drm_mode_fb_cmd2 *mode_cmd,
> +			       struct drm_gem_object **obj,
> +			       unsigned int num_planes,
> +			       const struct drm_framebuffer_funcs *funcs)
> +{
> +	int ret, i;
> +
> +	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
> +
> +	for (i = 0; i < num_planes; i++)
> +		fb->obj[i] = obj[i];
> +
> +	ret = drm_framebuffer_init(dev, fb, funcs);
> +	if (ret)
> +		DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", ret);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_fb_init_with_funcs);
> +
> +static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
> +	.destroy	= drm_gem_fb_destroy,
> +	.create_handle	= drm_gem_fb_create_handle,
> +};
> +
> +/**
> + * drm_gem_fb_init() - Initialize an already allocated framebuffer
> + * @fb: Framebuffer
> + * @dev: DRM device
> + * @mode_cmd: Metadata from the userspace framebuffer creation request
> + * @obj: GEM objects to be assigned to the framebuffer
> + * @num_planes: number of planes
> + *
> + * This variant of the function uses a default vtable.
> + *
> + * Returns:
> + * 0 on success or a negative error code
> + */
> +int drm_gem_fb_init(struct drm_framebuffer *fb,
> +		    struct drm_device *dev,
> +		    const struct drm_mode_fb_cmd2 *mode_cmd,
> +		    struct drm_gem_object **obj, unsigned int num_planes)
> +{
> +	return drm_gem_fb_init_with_funcs(fb, dev, mode_cmd, obj, num_planes, &drm_gem_fb_funcs);
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_fb_init);
> +
>  static struct drm_framebuffer *
>  drm_gem_fb_alloc(struct drm_device *dev,
>  		 const struct drm_mode_fb_cmd2 *mode_cmd,
> @@ -61,21 +124,14 @@ drm_gem_fb_alloc(struct drm_device *dev,
>  		 const struct drm_framebuffer_funcs *funcs)
>  {
>  	struct drm_framebuffer *fb;
> -	int ret, i;
> +	int ret;
>  
>  	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
>  	if (!fb)
>  		return ERR_PTR(-ENOMEM);
>  
> -	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
> -
> -	for (i = 0; i < num_planes; i++)
> -		fb->obj[i] = obj[i];
> -
> -	ret = drm_framebuffer_init(dev, fb, funcs);
> +	ret = drm_gem_fb_init_with_funcs(fb, dev, mode_cmd, obj, num_planes, funcs);
>  	if (ret) {
> -		DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
> -			      ret);
>  		kfree(fb);
>  		return ERR_PTR(ret);
>  	}
> @@ -144,59 +200,29 @@ drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
>  			     const struct drm_mode_fb_cmd2 *mode_cmd,
>  			     const struct drm_framebuffer_funcs *funcs)
>  {
> -	const struct drm_format_info *info;
>  	struct drm_gem_object *objs[4];
>  	struct drm_framebuffer *fb;
> -	int ret, i;
> -
> -	info = drm_get_format_info(dev, mode_cmd);
> -	if (!info)
> -		return ERR_PTR(-EINVAL);
> -
> -	for (i = 0; i < info->num_planes; i++) {
> -		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
> -		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
> -		unsigned int min_size;
> +	int ret, num_planes;
>  
> -		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
> -		if (!objs[i]) {
> -			DRM_DEBUG_KMS("Failed to lookup GEM object\n");
> -			ret = -ENOENT;
> -			goto err_gem_object_put;
> -		}
> -
> -		min_size = (height - 1) * mode_cmd->pitches[i]
> -			 + drm_format_info_min_pitch(info, i, width)
> -			 + mode_cmd->offsets[i];
> +	ret = drm_gem_fb_lookup(dev, file, mode_cmd, objs);
> +	if (ret < 0)
> +		return ERR_PTR(ret);
> +	num_planes = ret;
>  
> -		if (objs[i]->size < min_size) {
> -			drm_gem_object_put_unlocked(objs[i]);
> -			ret = -EINVAL;
> -			goto err_gem_object_put;
> -		}
> -	}
> +	ret = drm_gem_fb_size_check(dev, mode_cmd, objs);
> +	if (ret)
> +		fb = ERR_PTR(ret);
> +	else
> +		fb = drm_gem_fb_alloc(dev, mode_cmd, objs, num_planes, funcs);
>  
> -	fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
> -	if (IS_ERR(fb)) {
> -		ret = PTR_ERR(fb);
> -		goto err_gem_object_put;
> -	}
> +	if (IS_ERR(fb))
> +		for (num_planes--; num_planes >= 0; num_planes--)
> +			drm_gem_object_put_unlocked(objs[num_planes]);
>  
>  	return fb;
> -
> -err_gem_object_put:
> -	for (i--; i >= 0; i--)
> -		drm_gem_object_put_unlocked(objs[i]);
> -
> -	return ERR_PTR(ret);
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
>  
> -static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
> -	.destroy	= drm_gem_fb_destroy,
> -	.create_handle	= drm_gem_fb_create_handle,
> -};
> -
>  /**
>   * drm_gem_fb_create() - Helper function for the
>   *                       &drm_mode_config_funcs.fb_create callback
> @@ -228,6 +254,92 @@ drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_fb_create);
>  
> +/**
> + * drm_gem_fb_lookup() - Helper function for use in
> + *			 &drm_mode_config_funcs.fb_create implementations
> + * @dev: DRM device
> + * @file: DRM file that holds the GEM handle(s) backing the framebuffer
> + * @mode_cmd: Metadata from the userspace framebuffer creation request
> + *
> + * This function can be used to look up the objects for all planes.
> + * In case an error is returned all the objects are put by the
> + * function before returning.
> + *
> + * Returns:
> + * Number of planes on success or a negative error code on failure.
> + */
> +int drm_gem_fb_lookup(struct drm_device *dev,

[nit-pick] How about name it to drm_gem_fb_objs_lookup() ?

> +		      struct drm_file *file,
> +		      const struct drm_mode_fb_cmd2 *mode_cmd,
> +		      struct drm_gem_object **objs)
> +{
> +	const struct drm_format_info *info;
> +	int ret, i;
> +
> +	info = drm_get_format_info(dev, mode_cmd);
> +	if (!info)
> +		return -EINVAL;
> +
> +	for (i = 0; i < info->num_planes; i++) {
> +		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
> +		if (!objs[i]) {
> +			DRM_DEBUG_KMS("Failed to lookup GEM object\n");
> +			ret = -ENOENT;
> +			goto err_gem_object_put;
> +		}
> +	}
> +
> +	return i;
> +
> +err_gem_object_put:
> +	for (i--; i >= 0; i--)
> +		drm_gem_object_put_unlocked(objs[i]);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_fb_lookup);
> +
> +/**
> + * drm_gem_fb_size_check() - Helper function for use in
> + *			     &drm_mode_config_funcs.fb_create implementations
> + * @dev: DRM device
> + * @mode_cmd: Metadata from the userspace framebuffer creation request
> + *
> + * This function can be used to verify buffer sizes for all planes.
> + * It is caller's responsibility to put the objects on failure.
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +int drm_gem_fb_size_check(struct drm_device *dev,
> +			  const struct drm_mode_fb_cmd2 *mode_cmd,
> +			  struct drm_gem_object **objs)
> +{
> +	const struct drm_format_info *info;
> +	int i;
> +
> +	info = drm_get_format_info(dev, mode_cmd);
> +	if (!info)
> +		return -EINVAL;
> +
> +	for (i = 0; i < info->num_planes; i++) {
> +		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
> +		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
> +		unsigned int min_size;
> +
> +		min_size = (height - 1) * mode_cmd->pitches[i]
> +			 + drm_format_info_min_pitch(info, i, width)
> +			 + mode_cmd->offsets[i];
> +
> +		if (objs[i]->size < min_size)
> +			return -EINVAL;
> +	}
> +
> +	return 0;
> +
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_fb_size_check);
> +
>  static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = {
>  	.destroy	= drm_gem_fb_destroy,
>  	.create_handle	= drm_gem_fb_create_handle,
> diff --git a/include/drm/drm_gem_framebuffer_helper.h b/include/drm/drm_gem_framebuffer_helper.h
> index d9f13fd25b0a..c85d4b152e91 100644
> --- a/include/drm/drm_gem_framebuffer_helper.h
> +++ b/include/drm/drm_gem_framebuffer_helper.h
> @@ -14,10 +14,27 @@ struct drm_simple_display_pipe;
>  
>  struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
>  					  unsigned int plane);
> +int drm_gem_fb_init_with_funcs(struct drm_framebuffer *fb,
> +			       struct drm_device *dev,
> +			       const struct drm_mode_fb_cmd2 *mode_cmd,
> +			       struct drm_gem_object **obj,
> +			       unsigned int num_planes,
> +			       const struct drm_framebuffer_funcs *funcs);
> +int drm_gem_fb_init(struct drm_framebuffer *fb,
> +		    struct drm_device *dev,
> +		    const struct drm_mode_fb_cmd2 *mode_cmd,
> +		    struct drm_gem_object **obj, unsigned int num_planes);
>  void drm_gem_fb_destroy(struct drm_framebuffer *fb);
>  int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
>  			     unsigned int *handle);
>  
> +int drm_gem_fb_lookup(struct drm_device *dev,
> +		      struct drm_file *file,
> +		      const struct drm_mode_fb_cmd2 *mode_cmd,
> +		      struct drm_gem_object **objs);
> +int drm_gem_fb_size_check(struct drm_device *dev,
> +			  const struct drm_mode_fb_cmd2 *mode_cmd,
> +			  struct drm_gem_object **objs);
>  struct drm_framebuffer *
>  drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
>  			     const struct drm_mode_fb_cmd2 *mode_cmd,
Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>

James.

> -- 
> 2.17.1
Boris Brezillon Feb. 20, 2020, 9:47 a.m. UTC | #2 
On Tue, 17 Dec 2019 15:49:48 +0100
Andrzej Pietrasiewicz <andrzej.p@collabora.com> wrote:

> +/**
> + * drm_gem_fb_size_check() - Helper function for use in
> + *			     &drm_mode_config_funcs.fb_create implementations
> + * @dev: DRM device
> + * @mode_cmd: Metadata from the userspace framebuffer creation request
> + *
> + * This function can be used to verify buffer sizes for all planes.
> + * It is caller's responsibility to put the objects on failure.
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +int drm_gem_fb_size_check(struct drm_device *dev,
> +			  const struct drm_mode_fb_cmd2 *mode_cmd,
> +			  struct drm_gem_object **objs)

Maybe we should rename that one drm_gem_fb_linear_size_check().

> +{
> +	const struct drm_format_info *info;
> +	int i;
> +
> +	info = drm_get_format_info(dev, mode_cmd);
> +	if (!info)
> +		return -EINVAL;
> +
> +	for (i = 0; i < info->num_planes; i++) {
> +		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
> +		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
> +		unsigned int min_size;
> +
> +		min_size = (height - 1) * mode_cmd->pitches[i]
> +			 + drm_format_info_min_pitch(info, i, width)
> +			 + mode_cmd->offsets[i];
> +
> +		if (objs[i]->size < min_size)
> +			return -EINVAL;
> +	}
> +
> +	return 0;
> +
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_fb_size_check);
> +
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index b9bcd310ca2d..b3494f6b66bb 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -54,6 +54,69 @@  struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
 }
 EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj);
 
+/**
+ * drm_gem_fb_init_with_funcs() - Initialize an already allocated framebuffer
+ * @fb: Framebuffer
+ * @dev: DRM device
+ * @mode_cmd: Metadata from the userspace framebuffer creation request
+ * @obj: GEM objects to be assigned to the framebuffer
+ * @num_planes: number of planes
+ * @funcs: vtable to be used for the framebuffer object
+ *
+ * This variant of the function allows passing a custom vtable.
+ *
+ * Returns:
+ * 0 on success or a negative error code
+ */
+int drm_gem_fb_init_with_funcs(struct drm_framebuffer *fb,
+			       struct drm_device *dev,
+			       const struct drm_mode_fb_cmd2 *mode_cmd,
+			       struct drm_gem_object **obj,
+			       unsigned int num_planes,
+			       const struct drm_framebuffer_funcs *funcs)
+{
+	int ret, i;
+
+	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
+
+	for (i = 0; i < num_planes; i++)
+		fb->obj[i] = obj[i];
+
+	ret = drm_framebuffer_init(dev, fb, funcs);
+	if (ret)
+		DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(drm_gem_fb_init_with_funcs);
+
+static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
+	.destroy	= drm_gem_fb_destroy,
+	.create_handle	= drm_gem_fb_create_handle,
+};
+
+/**
+ * drm_gem_fb_init() - Initialize an already allocated framebuffer
+ * @fb: Framebuffer
+ * @dev: DRM device
+ * @mode_cmd: Metadata from the userspace framebuffer creation request
+ * @obj: GEM objects to be assigned to the framebuffer
+ * @num_planes: number of planes
+ *
+ * This variant of the function uses a default vtable.
+ *
+ * Returns:
+ * 0 on success or a negative error code
+ */
+int drm_gem_fb_init(struct drm_framebuffer *fb,
+		    struct drm_device *dev,
+		    const struct drm_mode_fb_cmd2 *mode_cmd,
+		    struct drm_gem_object **obj, unsigned int num_planes)
+{
+	return drm_gem_fb_init_with_funcs(fb, dev, mode_cmd, obj, num_planes, &drm_gem_fb_funcs);
+}
+EXPORT_SYMBOL_GPL(drm_gem_fb_init);
+
 static struct drm_framebuffer *
 drm_gem_fb_alloc(struct drm_device *dev,
 		 const struct drm_mode_fb_cmd2 *mode_cmd,
@@ -61,21 +124,14 @@  drm_gem_fb_alloc(struct drm_device *dev,
 		 const struct drm_framebuffer_funcs *funcs)
 {
 	struct drm_framebuffer *fb;
-	int ret, i;
+	int ret;
 
 	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
 	if (!fb)
 		return ERR_PTR(-ENOMEM);
 
-	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
-
-	for (i = 0; i < num_planes; i++)
-		fb->obj[i] = obj[i];
-
-	ret = drm_framebuffer_init(dev, fb, funcs);
+	ret = drm_gem_fb_init_with_funcs(fb, dev, mode_cmd, obj, num_planes, funcs);
 	if (ret) {
-		DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n",
-			      ret);
 		kfree(fb);
 		return ERR_PTR(ret);
 	}
@@ -144,59 +200,29 @@  drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
 			     const struct drm_mode_fb_cmd2 *mode_cmd,
 			     const struct drm_framebuffer_funcs *funcs)
 {
-	const struct drm_format_info *info;
 	struct drm_gem_object *objs[4];
 	struct drm_framebuffer *fb;
-	int ret, i;
-
-	info = drm_get_format_info(dev, mode_cmd);
-	if (!info)
-		return ERR_PTR(-EINVAL);
-
-	for (i = 0; i < info->num_planes; i++) {
-		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
-		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
-		unsigned int min_size;
+	int ret, num_planes;
 
-		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
-		if (!objs[i]) {
-			DRM_DEBUG_KMS("Failed to lookup GEM object\n");
-			ret = -ENOENT;
-			goto err_gem_object_put;
-		}
-
-		min_size = (height - 1) * mode_cmd->pitches[i]
-			 + drm_format_info_min_pitch(info, i, width)
-			 + mode_cmd->offsets[i];
+	ret = drm_gem_fb_lookup(dev, file, mode_cmd, objs);
+	if (ret < 0)
+		return ERR_PTR(ret);
+	num_planes = ret;
 
-		if (objs[i]->size < min_size) {
-			drm_gem_object_put_unlocked(objs[i]);
-			ret = -EINVAL;
-			goto err_gem_object_put;
-		}
-	}
+	ret = drm_gem_fb_size_check(dev, mode_cmd, objs);
+	if (ret)
+		fb = ERR_PTR(ret);
+	else
+		fb = drm_gem_fb_alloc(dev, mode_cmd, objs, num_planes, funcs);
 
-	fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs);
-	if (IS_ERR(fb)) {
-		ret = PTR_ERR(fb);
-		goto err_gem_object_put;
-	}
+	if (IS_ERR(fb))
+		for (num_planes--; num_planes >= 0; num_planes--)
+			drm_gem_object_put_unlocked(objs[num_planes]);
 
 	return fb;
-
-err_gem_object_put:
-	for (i--; i >= 0; i--)
-		drm_gem_object_put_unlocked(objs[i]);
-
-	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs);
 
-static const struct drm_framebuffer_funcs drm_gem_fb_funcs = {
-	.destroy	= drm_gem_fb_destroy,
-	.create_handle	= drm_gem_fb_create_handle,
-};
-
 /**
  * drm_gem_fb_create() - Helper function for the
  *                       &drm_mode_config_funcs.fb_create callback
@@ -228,6 +254,92 @@  drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
 }
 EXPORT_SYMBOL_GPL(drm_gem_fb_create);
 
+/**
+ * drm_gem_fb_lookup() - Helper function for use in
+ *			 &drm_mode_config_funcs.fb_create implementations
+ * @dev: DRM device
+ * @file: DRM file that holds the GEM handle(s) backing the framebuffer
+ * @mode_cmd: Metadata from the userspace framebuffer creation request
+ *
+ * This function can be used to look up the objects for all planes.
+ * In case an error is returned all the objects are put by the
+ * function before returning.
+ *
+ * Returns:
+ * Number of planes on success or a negative error code on failure.
+ */
+int drm_gem_fb_lookup(struct drm_device *dev,
+		      struct drm_file *file,
+		      const struct drm_mode_fb_cmd2 *mode_cmd,
+		      struct drm_gem_object **objs)
+{
+	const struct drm_format_info *info;
+	int ret, i;
+
+	info = drm_get_format_info(dev, mode_cmd);
+	if (!info)
+		return -EINVAL;
+
+	for (i = 0; i < info->num_planes; i++) {
+		objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
+		if (!objs[i]) {
+			DRM_DEBUG_KMS("Failed to lookup GEM object\n");
+			ret = -ENOENT;
+			goto err_gem_object_put;
+		}
+	}
+
+	return i;
+
+err_gem_object_put:
+	for (i--; i >= 0; i--)
+		drm_gem_object_put_unlocked(objs[i]);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(drm_gem_fb_lookup);
+
+/**
+ * drm_gem_fb_size_check() - Helper function for use in
+ *			     &drm_mode_config_funcs.fb_create implementations
+ * @dev: DRM device
+ * @mode_cmd: Metadata from the userspace framebuffer creation request
+ *
+ * This function can be used to verify buffer sizes for all planes.
+ * It is caller's responsibility to put the objects on failure.
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+int drm_gem_fb_size_check(struct drm_device *dev,
+			  const struct drm_mode_fb_cmd2 *mode_cmd,
+			  struct drm_gem_object **objs)
+{
+	const struct drm_format_info *info;
+	int i;
+
+	info = drm_get_format_info(dev, mode_cmd);
+	if (!info)
+		return -EINVAL;
+
+	for (i = 0; i < info->num_planes; i++) {
+		unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
+		unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
+		unsigned int min_size;
+
+		min_size = (height - 1) * mode_cmd->pitches[i]
+			 + drm_format_info_min_pitch(info, i, width)
+			 + mode_cmd->offsets[i];
+
+		if (objs[i]->size < min_size)
+			return -EINVAL;
+	}
+
+	return 0;
+
+}
+EXPORT_SYMBOL_GPL(drm_gem_fb_size_check);
+
 static const struct drm_framebuffer_funcs drm_gem_fb_funcs_dirtyfb = {
 	.destroy	= drm_gem_fb_destroy,
 	.create_handle	= drm_gem_fb_create_handle,
diff --git a/include/drm/drm_gem_framebuffer_helper.h b/include/drm/drm_gem_framebuffer_helper.h
index d9f13fd25b0a..c85d4b152e91 100644
--- a/include/drm/drm_gem_framebuffer_helper.h
+++ b/include/drm/drm_gem_framebuffer_helper.h
@@ -14,10 +14,27 @@  struct drm_simple_display_pipe;
 
 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
 					  unsigned int plane);
+int drm_gem_fb_init_with_funcs(struct drm_framebuffer *fb,
+			       struct drm_device *dev,
+			       const struct drm_mode_fb_cmd2 *mode_cmd,
+			       struct drm_gem_object **obj,
+			       unsigned int num_planes,
+			       const struct drm_framebuffer_funcs *funcs);
+int drm_gem_fb_init(struct drm_framebuffer *fb,
+		    struct drm_device *dev,
+		    const struct drm_mode_fb_cmd2 *mode_cmd,
+		    struct drm_gem_object **obj, unsigned int num_planes);
 void drm_gem_fb_destroy(struct drm_framebuffer *fb);
 int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
 			     unsigned int *handle);
 
+int drm_gem_fb_lookup(struct drm_device *dev,
+		      struct drm_file *file,
+		      const struct drm_mode_fb_cmd2 *mode_cmd,
+		      struct drm_gem_object **objs);
+int drm_gem_fb_size_check(struct drm_device *dev,
+			  const struct drm_mode_fb_cmd2 *mode_cmd,
+			  struct drm_gem_object **objs);
 struct drm_framebuffer *
 drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
 			     const struct drm_mode_fb_cmd2 *mode_cmd,