drm/atomic: Add drm_atomic_crtc_state_for_each_plane_state

... and use it in msm&vc4. Again just want to encapsulate
drm_atomic_state internals a bit.

The const threading is a bit awkward in vc4 since C sucks, but I still
think it's worth to enforce this. Eventually I want to make all the
obj->state pointers const too, but that's a lot more work ...

v2: Provide safe macro to wrap up the unsafe helper better, suggested
by Maarten.

v3: Fixup subject (Maarten) and spelling fixes (Eric Engestrom).

Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464877304-4213-1-git-send-email-daniel.vetter@ffwll.ch

3 files changed, 6 insertions, 14 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 904d0754ad78..ba2e373ec901 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -395,6 +395,7 @@ static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	struct drm_plane *plane;
 	unsigned long flags;
+	const struct drm_plane_state *plane_state;
 	u32 dlist_count = 0;
 	int ret;
 
@@ -404,18 +405,8 @@ static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
 	if (hweight32(state->connector_mask) > 1)
 		return -EINVAL;
 
-	drm_atomic_crtc_state_for_each_plane(plane, state) {
-		struct drm_plane_state *plane_state =
-			state->state->plane_states[drm_plane_index(plane)];
-
-		/* plane might not have changed, in which case take
-		 * current state:
-		 */
-		if (!plane_state)
-			plane_state = plane->state;
-
+	drm_atomic_crtc_state_for_each_plane_state(plane, plane_state, state)
 		dlist_count += vc4_plane_dlist_size(plane_state);
-	}
 
 	dlist_count++; /* Account for SCALER_CTL0_END. */
 
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 37cac59401d7..c799baabc008 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -469,7 +469,7 @@ int vc4_kms_load(struct drm_device *dev);
 struct drm_plane *vc4_plane_init(struct drm_device *dev,
 				 enum drm_plane_type type);
 u32 vc4_plane_write_dlist(struct drm_plane *plane, u32 __iomem *dlist);
-u32 vc4_plane_dlist_size(struct drm_plane_state *state);
+u32 vc4_plane_dlist_size(const struct drm_plane_state *state);
 void vc4_plane_async_set_fb(struct drm_plane *plane,
 			    struct drm_framebuffer *fb);
 
diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index 4037b52fde31..5d2c3d9fd17a 100644
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -690,9 +690,10 @@ u32 vc4_plane_write_dlist(struct drm_plane *plane, u32 __iomem *dlist)
 	return vc4_state->dlist_count;
 }
 
-u32 vc4_plane_dlist_size(struct drm_plane_state *state)
+u32 vc4_plane_dlist_size(const struct drm_plane_state *state)
 {
-	struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
+	const struct vc4_plane_state *vc4_state =
+		container_of(state, typeof(*vc4_state), base);
 
 	return vc4_state->dlist_count;
 }