drm/mipi-dbi: Support shadow-plane state

Implement MIPI DBI planes with struct drm_shadow_plane_state, so that the
respective drivers can use the vmap'ed GEM-buffer memory. Implement state
helpers, the {begin,end}_fb_access helpers and wire up everything.

With this commit, MIPI DBI drivers can access the GEM object's memory
that is provided by shadow-plane state. The actual changes to drivers
are implemented separately.

v2:
	* use shadow-plane state directly (Noralf)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org> # drm/tiny/mi0283qt
Link: https://patchwork.freedesktop.org/patch/msgid/20221202125644.7917-7-tzimmermann@suse.de

1 files changed, 85 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index f58123327ed6..b808de61c5bc 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -21,6 +21,7 @@
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem.h>
+#include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_mipi_dbi.h>
 #include <drm/drm_modes.h>
@@ -433,6 +434,90 @@ void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe)
 }
 EXPORT_SYMBOL(mipi_dbi_pipe_disable);
 
+/**
+ * mipi_dbi_pipe_begin_fb_access - MIPI DBI pipe begin-access helper
+ * @pipe: Display pipe
+ * @plane_state: Plane state
+ *
+ * This function implements struct &drm_simple_display_funcs.begin_fb_access.
+ *
+ * See drm_gem_begin_shadow_fb_access() for details and mipi_dbi_pipe_cleanup_fb()
+ * for cleanup.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int mipi_dbi_pipe_begin_fb_access(struct drm_simple_display_pipe *pipe,
+				  struct drm_plane_state *plane_state)
+{
+	return drm_gem_begin_shadow_fb_access(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_begin_fb_access);
+
+/**
+ * mipi_dbi_pipe_end_fb_access - MIPI DBI pipe end-access helper
+ * @pipe: Display pipe
+ * @plane_state: Plane state
+ *
+ * This function implements struct &drm_simple_display_funcs.end_fb_access.
+ *
+ * See mipi_dbi_pipe_begin_fb_access().
+ */
+void mipi_dbi_pipe_end_fb_access(struct drm_simple_display_pipe *pipe,
+				 struct drm_plane_state *plane_state)
+{
+	drm_gem_end_shadow_fb_access(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_end_fb_access);
+
+/**
+ * mipi_dbi_pipe_reset_plane - MIPI DBI plane-reset helper
+ * @pipe: Display pipe
+ *
+ * This function implements struct &drm_simple_display_funcs.reset_plane
+ * for MIPI DBI planes.
+ */
+void mipi_dbi_pipe_reset_plane(struct drm_simple_display_pipe *pipe)
+{
+	drm_gem_reset_shadow_plane(&pipe->plane);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_reset_plane);
+
+/**
+ * mipi_dbi_pipe_duplicate_plane_state - duplicates MIPI DBI plane state
+ * @pipe: Display pipe
+ *
+ * This function implements struct &drm_simple_display_funcs.duplicate_plane_state
+ * for MIPI DBI planes.
+ *
+ * See drm_gem_duplicate_shadow_plane_state() for additional details.
+ *
+ * Returns:
+ * A pointer to a new plane state on success, or NULL otherwise.
+ */
+struct drm_plane_state *mipi_dbi_pipe_duplicate_plane_state(struct drm_simple_display_pipe *pipe)
+{
+	return drm_gem_duplicate_shadow_plane_state(&pipe->plane);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_duplicate_plane_state);
+
+/**
+ * mipi_dbi_pipe_destroy_plane_state - cleans up MIPI DBI plane state
+ * @pipe: Display pipe
+ * @plane_state: Plane state
+ *
+ * This function implements struct drm_simple_display_funcs.destroy_plane_state
+ * for MIPI DBI planes.
+ *
+ * See drm_gem_destroy_shadow_plane_state() for additional details.
+ */
+void mipi_dbi_pipe_destroy_plane_state(struct drm_simple_display_pipe *pipe,
+				       struct drm_plane_state *plane_state)
+{
+	drm_gem_destroy_shadow_plane_state(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_destroy_plane_state);
+
 static int mipi_dbi_connector_get_modes(struct drm_connector *connector)
 {
 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(connector->dev);