drm/gem: Export helpers for shadow-buffered planes (9dc9067d) · Commits · EulixOS / Software / Kernel

drivers/gpu/drm/drm_gem_atomic_helper.c

+142 −6

Original line number	Diff line number	Diff line
		@@ -14,13 +14,101 @@
		* functions for drivers that use GEM objects. Currently, it provides
		* plane state and framebuffer BO mappings for planes with shadow
		* buffers.
		*
		* A driver using a shadow buffer copies the content of the shadow buffers
		* into the HW's framebuffer memory during an atomic update. This requires
		* a mapping of the shadow buffer into kernel address space. The mappings
		* cannot be established by commit-tail functions, such as atomic_update,
		* as this would violate locking rules around dma_buf_vmap().
		*
		* The helpers for shadow-buffered planes establish and release mappings,
		* and provide struct drm_shadow_plane_state, which stores the plane's mapping
		* for commit-tail functons.
		*
		* Shadow-buffered planes can easily be enabled by using the provided macros
		* %DRM_GEM_SHADOW_PLANE_FUNCS and %DRM_GEM_SHADOW_PLANE_HELPER_FUNCS.
		* These macros set up the plane and plane-helper callbacks to point to the
		* shadow-buffer helpers.
		*
		* .. code-block:: c
		*
		* #include <drm/drm/gem_atomic_helper.h>
		*
		* struct drm_plane_funcs driver_plane_funcs = {
		* ...,
		* DRM_GEM_SHADOW_PLANE_FUNCS,
		* };
		*
		* struct drm_plane_helper_funcs driver_plane_helper_funcs = {
		* ...,
		* DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
		* };
		*
		* In the driver's atomic-update function, shadow-buffer mappings are available
		* from the plane state. Use to_drm_shadow_plane_state() to upcast from
		* struct drm_plane_state.
		*
		* .. code-block:: c
		*
		* void driver_plane_atomic_update(struct drm_plane *plane,
		* struct drm_plane_state *old_plane_state)
		* {
		* struct drm_plane_state *plane_state = plane->state;
		* struct drm_shadow_plane_state *shadow_plane_state =
		* to_drm_shadow_plane_state(plane_state);
		*
		* // access shadow buffer via shadow_plane_state->map
		* }
		*
		* A mapping address for each of the framebuffer's buffer object is stored in
		* struct &drm_shadow_plane_state.map. The mappings are valid while the state
		* is being used.
		*
		* Drivers that use struct drm_simple_display_pipe can use
		* %DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS to initialize the rsp
		* callbacks. Access to shadow-buffer mappings is similar to regular
		* atomic_update.
		*
		* .. code-block:: c
		*
		* struct drm_simple_display_pipe_funcs driver_pipe_funcs = {
		* ...,
		* DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
		* };
		*
		* void driver_pipe_enable(struct drm_simple_display_pipe *pipe,
		* struct drm_crtc_state *crtc_state,
		* struct drm_plane_state *plane_state)
		* {
		* struct drm_shadow_plane_state *shadow_plane_state =
		* to_drm_shadow_plane_state(plane_state);
		*
		* // access shadow buffer via shadow_plane_state->map
		* }
		*/

		/*
		* Shadow-buffered Planes
		*/

		static struct drm_plane_state *
		/**
		* drm_gem_duplicate_shadow_plane_state - duplicates shadow-buffered plane state
		* @plane: the plane
		*
		* This function implements struct &drm_plane_funcs.atomic_duplicate_state for
		* shadow-buffered planes. It assumes the existing state to be of type
		* struct drm_shadow_plane_state and it allocates the new state to be of this
		* type.
		*
		* The function does not duplicate existing mappings of the shadow buffers.
		* Mappings are maintained during the atomic commit by the plane's prepare_fb
		* and cleanup_fb helpers. See drm_gem_prepare_shadow_fb() and drm_gem_cleanup_shadow_fb()
		* for corresponding helpers.
		*
		* Returns:
		* A pointer to a new plane state on success, or NULL otherwise.
		*/
		struct drm_plane_state *
		drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane)
		{
		struct drm_plane_state *plane_state = plane->state;
		@@ -36,8 +124,18 @@ drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane)

		return &new_shadow_plane_state->base;
		}
		EXPORT_SYMBOL(drm_gem_duplicate_shadow_plane_state);

		static void drm_gem_destroy_shadow_plane_state(struct drm_plane *plane,
		/**
		* drm_gem_destroy_shadow_plane_state - deletes shadow-buffered plane state
		* @plane: the plane
		* @plane_state: the plane state of type struct drm_shadow_plane_state
		*
		* This function implements struct &drm_plane_funcs.atomic_destroy_state
		* for shadow-buffered planes. It expects that mappings of shadow buffers
		* have been released already.
		*/
		void drm_gem_destroy_shadow_plane_state(struct drm_plane *plane,
		struct drm_plane_state *plane_state)
		{
		struct drm_shadow_plane_state *shadow_plane_state =
		@@ -46,8 +144,18 @@ static void drm_gem_destroy_shadow_plane_state(struct drm_plane *plane,
		__drm_atomic_helper_plane_destroy_state(&shadow_plane_state->base);
		kfree(shadow_plane_state);
		}
		EXPORT_SYMBOL(drm_gem_destroy_shadow_plane_state);

		static void drm_gem_reset_shadow_plane(struct drm_plane *plane)
		/**
		* drm_gem_reset_shadow_plane - resets a shadow-buffered plane
		* @plane: the plane
		*
		* This function implements struct &drm_plane_funcs.reset_plane for
		* shadow-buffered planes. It assumes the current plane state to be
		* of type struct drm_shadow_plane and it allocates the new state of
		* this type.
		*/
		void drm_gem_reset_shadow_plane(struct drm_plane *plane)
		{
		struct drm_shadow_plane_state *shadow_plane_state;

		@@ -61,8 +169,24 @@ static void drm_gem_reset_shadow_plane(struct drm_plane *plane)
		return;
		__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
		}
		EXPORT_SYMBOL(drm_gem_reset_shadow_plane);

		static int drm_gem_prepare_shadow_fb(struct drm_plane plane, struct drm_plane_state plane_state)
		/**
		* drm_gem_prepare_shadow_fb - prepares shadow framebuffers
		* @plane: the plane
		* @plane_state: the plane state of type struct drm_shadow_plane_state
		*
		* This function implements struct &drm_plane_helper_funcs.prepare_fb. It
		* maps all buffer objects of the plane's framebuffer into kernel address
		* space and stores them in &struct drm_shadow_plane_state.map. The
		* framebuffer will be synchronized as part of the atomic commit.
		*
		* See drm_gem_cleanup_shadow_fb() for cleanup.
		*
		* Returns:
		* 0 on success, or a negative errno code otherwise.
		*/
		int drm_gem_prepare_shadow_fb(struct drm_plane plane, struct drm_plane_state plane_state)
		{
		struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
		struct drm_framebuffer *fb = plane_state->fb;
		@@ -100,8 +224,19 @@ static int drm_gem_prepare_shadow_fb(struct drm_plane *plane, struct drm_plane_s
		}
		return ret;
		}
		EXPORT_SYMBOL(drm_gem_prepare_shadow_fb);

		static void drm_gem_cleanup_shadow_fb(struct drm_plane plane, struct drm_plane_state plane_state)
		/**
		* drm_gem_cleanup_shadow_fb - releases shadow framebuffers
		* @plane: the plane
		* @plane_state: the plane state of type struct drm_shadow_plane_state
		*
		* This function implements struct &drm_plane_helper_funcs.cleanup_fb.
		* This function unmaps all buffer objects of the plane's framebuffer.
		*
		* See drm_gem_prepare_shadow_fb() for more inforamtion.
		*/
		void drm_gem_cleanup_shadow_fb(struct drm_plane plane, struct drm_plane_state plane_state)
		{
		struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
		struct drm_framebuffer *fb = plane_state->fb;
		@@ -119,6 +254,7 @@ static void drm_gem_cleanup_shadow_fb(struct drm_plane *plane, struct drm_plane_
		drm_gem_vunmap(obj, &shadow_plane_state->map[i]);
		}
		}
		EXPORT_SYMBOL(drm_gem_cleanup_shadow_fb);

		/**
		* drm_gem_simple_kms_prepare_shadow_fb - prepares shadow framebuffers

include/drm/drm_gem_atomic_helper.h

+32 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,38 @@ to_drm_shadow_plane_state(struct drm_plane_state *state)
		return container_of(state, struct drm_shadow_plane_state, base);
		}

		void drm_gem_reset_shadow_plane(struct drm_plane *plane);
		struct drm_plane_state drm_gem_duplicate_shadow_plane_state(struct drm_plane plane);
		void drm_gem_destroy_shadow_plane_state(struct drm_plane *plane,
		struct drm_plane_state *plane_state);

		/**
		* DRM_GEM_SHADOW_PLANE_FUNCS -
		* Initializes struct drm_plane_funcs for shadow-buffered planes
		*
		* Drivers may use GEM BOs as shadow buffers over the framebuffer memory. This
		* macro initializes struct drm_plane_funcs to use the rsp helper functions.
		*/
		#define DRM_GEM_SHADOW_PLANE_FUNCS \
		.reset = drm_gem_reset_shadow_plane, \
		.atomic_duplicate_state = drm_gem_duplicate_shadow_plane_state, \
		.atomic_destroy_state = drm_gem_destroy_shadow_plane_state

		int drm_gem_prepare_shadow_fb(struct drm_plane plane, struct drm_plane_state plane_state);
		void drm_gem_cleanup_shadow_fb(struct drm_plane plane, struct drm_plane_state plane_state);

		/**
		* DRM_GEM_SHADOW_PLANE_HELPER_FUNCS -
		* Initializes struct drm_plane_helper_funcs for shadow-buffered planes
		*
		* Drivers may use GEM BOs as shadow buffers over the framebuffer memory. This
		* macro initializes struct drm_plane_helper_funcs to use the rsp helper
		* functions.
		*/
		#define DRM_GEM_SHADOW_PLANE_HELPER_FUNCS \
		.prepare_fb = drm_gem_prepare_shadow_fb, \
		.cleanup_fb = drm_gem_cleanup_shadow_fb

		int drm_gem_simple_kms_prepare_shadow_fb(struct drm_simple_display_pipe *pipe,
		struct drm_plane_state *plane_state);
		void drm_gem_simple_kms_cleanup_shadow_fb(struct drm_simple_display_pipe *pipe,