drm/msm/mdp5: Prepare mdp5_pipe_assign for some rework

mdp5_pipe_assign currently returns the hwpipe pointer for the drm_plane.
Return it indirectly by setting a pointer passed as an argument. This
is needed because we want the func to find out the right hwpipe too.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp5/mdp5_pipe.c

@@ -17,19 +17,19 @@
 
 #include "mdp5_kms.h"
 
-struct mdp5_hw_pipe *mdp5_pipe_assign(struct drm_atomic_state *s,
-		struct drm_plane *plane, uint32_t caps, uint32_t blkcfg)
+int mdp5_pipe_assign(struct drm_atomic_state *s, struct drm_plane *plane,
+		     uint32_t caps, uint32_t blkcfg,
+		     struct mdp5_hw_pipe **hwpipe)
 {
 	struct msm_drm_private *priv = s->dev->dev_private;
 	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
 	struct mdp5_state *state;
 	struct mdp5_hw_pipe_state *old_state, *new_state;
-	struct mdp5_hw_pipe *hwpipe = NULL;
 	int i;
 
 	state = mdp5_get_state(s);
 	if (IS_ERR(state))
-		return ERR_CAST(state);
+		return PTR_ERR(state);
 
 	/* grab old_state after mdp5_get_state(), since now we hold lock: */
 	old_state = &mdp5_kms->state->hwpipe;
@@ -64,31 +64,31 @@ struct mdp5_hw_pipe *mdp5_pipe_assign(struct drm_atomic_state *s,
 		/* possible candidate, take the one with the
 		 * fewest unneeded caps bits set:
 		 */
-		if (!hwpipe || (hweight_long(cur->caps & ~caps) <
-				hweight_long(hwpipe->caps & ~caps)))
-			hwpipe = cur;
+		if (!(*hwpipe) || (hweight_long(cur->caps & ~caps) <
+				   hweight_long((*hwpipe)->caps & ~caps)))
+			*hwpipe = cur;
 	}
 
-	if (!hwpipe)
-		return ERR_PTR(-ENOMEM);
+	if (!(*hwpipe))
+		return -ENOMEM;
 
 	if (mdp5_kms->smp) {
 		int ret;
 
-		DBG("%s: alloc SMP blocks", hwpipe->name);
+		DBG("%s: alloc SMP blocks", (*hwpipe)->name);
 		ret = mdp5_smp_assign(mdp5_kms->smp, &state->smp,
-				hwpipe->pipe, blkcfg);
+				(*hwpipe)->pipe, blkcfg);
 		if (ret)
-			return ERR_PTR(-ENOMEM);
+			return -ENOMEM;
 
-		hwpipe->blkcfg = blkcfg;
+		(*hwpipe)->blkcfg = blkcfg;
 	}
 
 	DBG("%s: assign to plane %s for caps %x",
-			hwpipe->name, plane->name, caps);
-	new_state->hwpipe_to_plane[hwpipe->idx] = plane;
+			(*hwpipe)->name, plane->name, caps);
+	new_state->hwpipe_to_plane[(*hwpipe)->idx] = plane;
 
-	return hwpipe;
+	return 0;
 }
 
 void mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe)

drivers/gpu/drm/msm/mdp/mdp5/mdp5_pipe.h

@@ -44,9 +44,9 @@ struct mdp5_hw_pipe_state {
 	struct drm_plane *hwpipe_to_plane[SSPP_MAX];
 };
 
-struct mdp5_hw_pipe *__must_check
+int
 mdp5_pipe_assign(struct drm_atomic_state *s, struct drm_plane *plane,
-		uint32_t caps, uint32_t blkcfg);
+		 uint32_t caps, uint32_t blkcfg, struct mdp5_hw_pipe **hwpipe);
 void mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe);
 
 struct mdp5_hw_pipe *mdp5_pipe_init(enum mdp5_pipe pipe,

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

@@ -394,21 +394,21 @@ static int mdp5_plane_atomic_check_with_state(struct drm_crtc_state *crtc_state,
 			struct mdp5_hw_pipe *old_right_hwpipe =
 							  mdp5_state->r_hwpipe;
 
-			mdp5_state->hwpipe = mdp5_pipe_assign(state->state,
-					plane, caps, blkcfg);
-			if (IS_ERR(mdp5_state->hwpipe)) {
+			ret = mdp5_pipe_assign(state->state, plane, caps,
+					       blkcfg, &mdp5_state->hwpipe);
+			if (ret) {
 				DBG("%s: failed to assign hwpipe!", plane->name);
-				return PTR_ERR(mdp5_state->hwpipe);
+				return ret;
 			}
 
 			if (need_right_hwpipe) {
-				mdp5_state->r_hwpipe =
-					mdp5_pipe_assign(state->state, plane,
-							 caps, blkcfg);
-				if (IS_ERR(mdp5_state->r_hwpipe)) {
+				ret = mdp5_pipe_assign(state->state, plane,
+						       caps, blkcfg,
+						       &mdp5_state->r_hwpipe);
+				if (ret) {
 					DBG("%s: failed to assign right hwpipe",
 					    plane->name);
-					return PTR_ERR(mdp5_state->r_hwpipe);
+					return ret;
 				}
 			} else {
 				/*