drm/msm/mdp4: fix mixer setup for multi-crtc + planes

On mdp4 there is a single global LAYERMIXER_IN_CFG register.  The
previous logic to share that between multiple crtcs didn't actually
handle plane-disable very well.  Easier just to look at all of the
crtcs each time.
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c

@@ -167,34 +167,54 @@ static bool mdp4_crtc_mode_fixup(struct drm_crtc *crtc,
 	return true;
 }
 
-static void blend_setup(struct drm_crtc *crtc)
+/* statically (for now) map planes to mixer stage (z-order): */
+static const int idxs[] = {
+		[VG1]  = 1,
+		[VG2]  = 2,
+		[RGB1] = 0,
+		[RGB2] = 0,
+		[RGB3] = 0,
+		[VG3]  = 3,
+		[VG4]  = 4,
+
+};
+
+/* setup mixer config, for which we need to consider all crtc's and
+ * the planes attached to them
+ *
+ * TODO may possibly need some extra locking here
+ */
+static void setup_mixer(struct mdp4_kms *mdp4_kms)
 {
-	struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
-	struct mdp4_kms *mdp4_kms = get_kms(crtc);
-	struct drm_plane *plane;
-	int i, ovlp = mdp4_crtc->ovlp;
+	struct drm_mode_config *config = &mdp4_kms->dev->mode_config;
+	struct drm_crtc *crtc;
 	uint32_t mixer_cfg = 0;
 	static const enum mdp_mixer_stage_id stages[] = {
 			STAGE_BASE, STAGE0, STAGE1, STAGE2, STAGE3,
 	};
-	/* statically (for now) map planes to mixer stage (z-order): */
-	static const int idxs[] = {
-			[VG1]  = 1,
-			[VG2]  = 2,
-			[RGB1] = 0,
-			[RGB2] = 0,
-			[RGB3] = 0,
-			[VG3]  = 3,
-			[VG4]  = 4,
 
-	};
-	bool alpha[4]= { false, false, false, false };
+	list_for_each_entry(crtc, &config->crtc_list, head) {
+		struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
+		struct drm_plane *plane;
 
-	/* Don't rely on value read back from hw, but instead use our
-	 * own shadowed value.  Possibly disable/reenable looses the
-	 * previous value and goes back to power-on default?
-	 */
-	mixer_cfg = mdp4_kms->mixer_cfg;
+		for_each_plane_on_crtc(crtc, plane) {
+			enum mdp4_pipe pipe_id = mdp4_plane_pipe(plane);
+			int idx = idxs[pipe_id];
+			mixer_cfg = mixercfg(mixer_cfg, mdp4_crtc->mixer,
+					pipe_id, stages[idx]);
+		}
+	}
+
+	mdp4_write(mdp4_kms, REG_MDP4_LAYERMIXER_IN_CFG, mixer_cfg);
+}
+
+static void blend_setup(struct drm_crtc *crtc)
+{
+	struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
+	struct mdp4_kms *mdp4_kms = get_kms(crtc);
+	struct drm_plane *plane;
+	int i, ovlp = mdp4_crtc->ovlp;
+	bool alpha[4]= { false, false, false, false };
 
 	mdp4_write(mdp4_kms, REG_MDP4_OVLP_TRANSP_LOW0(ovlp), 0);
 	mdp4_write(mdp4_kms, REG_MDP4_OVLP_TRANSP_LOW1(ovlp), 0);
@@ -209,13 +229,8 @@ static void blend_setup(struct drm_crtc *crtc)
 					to_mdp_format(msm_framebuffer_format(plane->fb));
 			alpha[idx-1] = format->alpha_enable;
 		}
-		mixer_cfg = mixercfg(mixer_cfg, mdp4_crtc->mixer,
-				pipe_id, stages[idx]);
 	}
 
-	/* this shouldn't happen.. and seems to cause underflow: */
-	WARN_ON(!mixer_cfg);
-
 	for (i = 0; i < 4; i++) {
 		uint32_t op;
 
@@ -238,8 +253,7 @@ static void blend_setup(struct drm_crtc *crtc)
 		mdp4_write(mdp4_kms, REG_MDP4_OVLP_STAGE_TRANSP_HIGH1(ovlp, i), 0);
 	}
 
-	mdp4_kms->mixer_cfg = mixer_cfg;
-	mdp4_write(mdp4_kms, REG_MDP4_LAYERMIXER_IN_CFG, mixer_cfg);
+	setup_mixer(mdp4_kms);
 }
 
 static void mdp4_crtc_mode_set_nofb(struct drm_crtc *crtc)

drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h

@@ -32,13 +32,6 @@ struct mdp4_kms {
 
 	int rev;
 
-	/* Shadow value for MDP4_LAYERMIXER_IN_CFG.. since setup for all
-	 * crtcs/encoders is in one shared register, we need to update it
-	 * via read/modify/write.  But to avoid getting confused by power-
-	 * on-default values after resume, use this shadow value instead:
-	 */
-	uint32_t mixer_cfg;
-
 	/* mapper-id used to request GEM buffer mapped for scanout: */
 	int id;