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

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);

drivers/gpu/drm/tiny/ili9225.c

@@ -343,6 +343,11 @@ static const struct drm_simple_display_pipe_funcs ili9225_pipe_funcs = {
 	.enable		= ili9225_pipe_enable,
 	.disable	= ili9225_pipe_disable,
 	.update		= ili9225_pipe_update,
+	.begin_fb_access = mipi_dbi_pipe_begin_fb_access,
+	.end_fb_access	= mipi_dbi_pipe_end_fb_access,
+	.reset_plane	= mipi_dbi_pipe_reset_plane,
+	.duplicate_plane_state = mipi_dbi_pipe_duplicate_plane_state,
+	.destroy_plane_state = mipi_dbi_pipe_destroy_plane_state,
 };
 
 static const struct drm_display_mode ili9225_mode = {

drivers/gpu/drm/tiny/st7586.c

@@ -277,6 +277,11 @@ static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
 	.enable		= st7586_pipe_enable,
 	.disable	= st7586_pipe_disable,
 	.update		= st7586_pipe_update,
+	.begin_fb_access = mipi_dbi_pipe_begin_fb_access,
+	.end_fb_access	= mipi_dbi_pipe_end_fb_access,
+	.reset_plane	= mipi_dbi_pipe_reset_plane,
+	.duplicate_plane_state = mipi_dbi_pipe_duplicate_plane_state,
+	.destroy_plane_state = mipi_dbi_pipe_destroy_plane_state,
 };
 
 static const struct drm_display_mode st7586_mode = {

include/drm/drm_mipi_dbi.h

@@ -164,6 +164,15 @@ void mipi_dbi_enable_flush(struct mipi_dbi_dev *dbidev,
 			   struct drm_crtc_state *crtc_state,
 			   struct drm_plane_state *plan_state);
 void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe);
+int mipi_dbi_pipe_begin_fb_access(struct drm_simple_display_pipe *pipe,
+				  struct drm_plane_state *plane_state);
+void mipi_dbi_pipe_end_fb_access(struct drm_simple_display_pipe *pipe,
+				 struct drm_plane_state *plane_state);
+void mipi_dbi_pipe_reset_plane(struct drm_simple_display_pipe *pipe);
+struct drm_plane_state *mipi_dbi_pipe_duplicate_plane_state(struct drm_simple_display_pipe *pipe);
+void mipi_dbi_pipe_destroy_plane_state(struct drm_simple_display_pipe *pipe,
+				       struct drm_plane_state *plane_state);
+
 void mipi_dbi_hw_reset(struct mipi_dbi *dbi);
 bool mipi_dbi_display_is_on(struct mipi_dbi *dbi);
 int mipi_dbi_poweron_reset(struct mipi_dbi_dev *dbidev);
@@ -223,6 +232,11 @@ static inline void mipi_dbi_debugfs_init(struct drm_minor *minor) {}
 	.mode_valid = mipi_dbi_pipe_mode_valid, \
 	.enable = (enable_), \
 	.disable = mipi_dbi_pipe_disable, \
-	.update = mipi_dbi_pipe_update
+	.update = mipi_dbi_pipe_update, \
+	.begin_fb_access = mipi_dbi_pipe_begin_fb_access, \
+	.end_fb_access = mipi_dbi_pipe_end_fb_access, \
+	.reset_plane = mipi_dbi_pipe_reset_plane, \
+	.duplicate_plane_state = mipi_dbi_pipe_duplicate_plane_state, \
+	.destroy_plane_state = mipi_dbi_pipe_destroy_plane_state
 
 #endif /* __LINUX_MIPI_DBI_H */