drm/plane: Pass old state to ->atomic_update()

In most situations it will be useful to have the old state passed to the
->atomic_update() callback. For example if a plane is being disabled the
new state's .crtc field will be NULL, but some drivers may rely on this
field to program the CRTCs registers.

v2: rename variable to old_plane_state and remove redundant comment as
suggested by Daniel Vetter, remove an Exynos hunk that doesn't apply to
drm-next and add a hunk for pending MSM mdp5 changes

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_atomic_helper.c

@@ -1046,6 +1046,7 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev,
 	for (i = 0; i < nplanes; i++) {
 		struct drm_plane_helper_funcs *funcs;
 		struct drm_plane *plane = old_state->planes[i];
+		struct drm_plane_state *old_plane_state;
 
 		if (!plane)
 			continue;
@@ -1055,7 +1056,9 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev,
 		if (!funcs || !funcs->atomic_update)
 			continue;
 
-		funcs->atomic_update(plane);
+		old_plane_state = old_state->plane_states[i];
+
+		funcs->atomic_update(plane, old_plane_state);
 	}
 
 	for (i = 0; i < ncrtcs; i++) {

drivers/gpu/drm/drm_plane_helper.c

@@ -443,7 +443,7 @@ int drm_plane_helper_commit(struct drm_plane *plane,
 			crtc_funcs[i]->atomic_begin(crtc[i]);
 	}
 
-	plane_funcs->atomic_update(plane);
+	plane_funcs->atomic_update(plane, plane_state);
 
 	for (i = 0; i < 2; i++) {
 		if (crtc_funcs[i] && crtc_funcs[i]->atomic_flush)

drivers/gpu/drm/msm/mdp/mdp4/mdp4_plane.c

@@ -107,7 +107,8 @@ static int mdp4_plane_atomic_check(struct drm_plane *plane,
 	return 0;
 }
 
-static void mdp4_plane_atomic_update(struct drm_plane *plane)
+static void mdp4_plane_atomic_update(struct drm_plane *plane,
+				     struct drm_plane_state *old_state)
 {
 	struct drm_plane_state *state = plane->state;
 	int ret;

drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c

@@ -213,7 +213,8 @@ static int mdp5_plane_atomic_check(struct drm_plane *plane,
 	return 0;
 }
 
-static void mdp5_plane_atomic_update(struct drm_plane *plane)
+static void mdp5_plane_atomic_update(struct drm_plane *plane,
+				     struct drm_plane_state *old_state)
 {
 	struct mdp5_plane *mdp5_plane = to_mdp5_plane(plane);
 	struct drm_plane_state *state = plane->state;

include/drm/drm_plane_helper.h

@@ -60,7 +60,8 @@ struct drm_plane_helper_funcs {
 
 	int (*atomic_check)(struct drm_plane *plane,
 			    struct drm_plane_state *state);
-	void (*atomic_update)(struct drm_plane *plane);
+	void (*atomic_update)(struct drm_plane *plane,
+			      struct drm_plane_state *old_state);
 };
 
 static inline void drm_plane_helper_add(struct drm_plane *plane,