Hi Am 09.02.21 um 10:44 schrieb Daniel Vetter:
On Mon, Feb 08, 2021 at 02:50:43PM +0100, Thomas Zimmermann wrote:Export the helpers for shadow-buffered planes. These will be used by several drivers. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> --- drivers/gpu/drm/drm_gem_atomic_helper.c | 148 +++++++++++++++++++++++- include/drm/drm_gem_atomic_helper.h | 32 +++++ 2 files changed, 174 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c index e27762cef360..79b4d3f0495a 100644 --- a/drivers/gpu/drm/drm_gem_atomic_helper.c +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c @@ -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 vmap."... 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_PLANE_SHADOW_FUNCS and DRM_GEM_SHADOE_PLANE_HELPER_FUNCS.I think for hyperlinks/highlights we need %CONSTANT? Maybe check what works.+ * 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 forDoes this hyperlink automatically? I didn't know it works since for members I just always use &struct.member myself.
Ah, ok. Fixed. This work with struct &name.field. The % only adds formatting to constants.
Best regards Thomas
+ * 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; @@ -36,9 +124,19 @@ 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,- struct drm_plane_state *plane_state) +/** + * 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 = to_drm_shadow_plane_state(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 diff --git a/include/drm/drm_gem_atomic_helper.h b/include/drm/drm_gem_atomic_helper.h index 08b96ccea325..7abf40bdab3d 100644 --- a/include/drm/drm_gem_atomic_helper.h +++ b/include/drm/drm_gem_atomic_helper.h @@ -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,Very nice and thoroughly explained docs! Thanks, Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>-- 2.30.0
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer
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