drm/gem: Export implementation of shadow-plane helpers

Export the implementation of duplicate, destroy and reset helpers for
shadow-buffered plane state. Useful for drivers that subclass struct
drm_shadow_plane_state.

The exported functions are wrappers around plane-state implementation,
but using them is the correct thing to do for drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210705074633.9425-2-tzimmermann@suse.de

drivers/gpu/drm/drm_gem_atomic_helper.c

@@ -182,6 +182,27 @@ EXPORT_SYMBOL(drm_gem_simple_display_pipe_prepare_fb);
  * Shadow-buffered Planes
  */
 
+/**
+ * __drm_gem_duplicate_shadow_plane_state - duplicates shadow-buffered plane state
+ * @plane: the plane
+ * @new_shadow_plane_state: the new shadow-buffered plane state
+ *
+ * This function duplicates shadow-buffered plane state. This is helpful for drivers
+ * that subclass struct drm_shadow_plane_state.
+ *
+ * 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.
+ */
+void
+__drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane,
+				       struct drm_shadow_plane_state *new_shadow_plane_state)
+{
+	__drm_atomic_helper_plane_duplicate_state(plane, &new_shadow_plane_state->base);
+}
+EXPORT_SYMBOL(__drm_gem_duplicate_shadow_plane_state);
+
 /**
  * drm_gem_duplicate_shadow_plane_state - duplicates shadow-buffered plane state
  * @plane: the plane
@@ -211,12 +232,25 @@ drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane)
 	new_shadow_plane_state = kzalloc(sizeof(*new_shadow_plane_state), GFP_KERNEL);
 	if (!new_shadow_plane_state)
 		return NULL;
-	__drm_atomic_helper_plane_duplicate_state(plane, &new_shadow_plane_state->base);
+	__drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
 
 	return &new_shadow_plane_state->base;
 }
 EXPORT_SYMBOL(drm_gem_duplicate_shadow_plane_state);
 
+/**
+ * __drm_gem_destroy_shadow_plane_state - cleans up shadow-buffered plane state
+ * @shadow_plane_state: the shadow-buffered plane state
+ *
+ * This function cleans up shadow-buffered plane state. Helpful for drivers that
+ * subclass struct drm_shadow_plane_state.
+ */
+void __drm_gem_destroy_shadow_plane_state(struct drm_shadow_plane_state *shadow_plane_state)
+{
+	__drm_atomic_helper_plane_destroy_state(&shadow_plane_state->base);
+}
+EXPORT_SYMBOL(__drm_gem_destroy_shadow_plane_state);
+
 /**
  * drm_gem_destroy_shadow_plane_state - deletes shadow-buffered plane state
  * @plane: the plane
@@ -232,11 +266,26 @@ void drm_gem_destroy_shadow_plane_state(struct drm_plane *plane,
 	struct drm_shadow_plane_state *shadow_plane_state =
 		to_drm_shadow_plane_state(plane_state);
 
-	__drm_atomic_helper_plane_destroy_state(&shadow_plane_state->base);
+	__drm_gem_destroy_shadow_plane_state(shadow_plane_state);
 	kfree(shadow_plane_state);
 }
 EXPORT_SYMBOL(drm_gem_destroy_shadow_plane_state);
 
+/**
+ * __drm_gem_reset_shadow_plane - resets a shadow-buffered plane
+ * @plane: the plane
+ * @shadow_plane_state: the shadow-buffered plane state
+ *
+ * This function resets state for shadow-buffered planes. Helpful
+ * for drivers that subclass struct drm_shadow_plane_state.
+ */
+void __drm_gem_reset_shadow_plane(struct drm_plane *plane,
+				  struct drm_shadow_plane_state *shadow_plane_state)
+{
+	__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+}
+EXPORT_SYMBOL(__drm_gem_reset_shadow_plane);
+
 /**
  * drm_gem_reset_shadow_plane - resets a shadow-buffered plane
  * @plane: the plane
@@ -258,7 +307,7 @@ void drm_gem_reset_shadow_plane(struct drm_plane *plane)
 	shadow_plane_state = kzalloc(sizeof(*shadow_plane_state), GFP_KERNEL);
 	if (!shadow_plane_state)
 		return;
-	__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+	__drm_gem_reset_shadow_plane(plane, shadow_plane_state);
 }
 EXPORT_SYMBOL(drm_gem_reset_shadow_plane);
 

include/drm/drm_gem_atomic_helper.h

@@ -53,6 +53,12 @@ to_drm_shadow_plane_state(struct drm_plane_state *state)
 	return container_of(state, struct drm_shadow_plane_state, base);
 }
 
+void __drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane,
+					    struct drm_shadow_plane_state *new_shadow_plane_state);
+void __drm_gem_destroy_shadow_plane_state(struct drm_shadow_plane_state *shadow_plane_state);
+void __drm_gem_reset_shadow_plane(struct drm_plane *plane,
+				  struct drm_shadow_plane_state *shadow_plane_state);
+
 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,