drm/msm: Use customized function to wait for atomic commit done

MDP FLUSH registers could indicate if the previous flush updates
has taken effect at vsync boundary. Making use of this H/W feature
can catch the vsync that happened between CRTC atomic_flush and
*_wait_for_vblanks, to avoid unnecessary wait.

This change allows kms CRTCs to use their own *_wait_for_commit_done
functions to wait for FLUSH register cleared at vsync, before commit
completion.

Signed-off-by: Hai Li <hali@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

3 files changed, 47 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
index 73afa21822b4..c4bb9d9c7667 100644
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
@@ -51,6 +51,11 @@ struct mdp4_crtc {
 	/* if there is a pending flip, these will be non-null: */
 	struct drm_pending_vblank_event *event;
 
+	/* Bits have been flushed at the last commit,
+	 * used to decide if a vsync has happened since last commit.
+	 */
+	u32 flushed_mask;
+
 #define PENDING_CURSOR 0x1
 #define PENDING_FLIP   0x2
 	atomic_t pending;
@@ -93,6 +98,8 @@ static void crtc_flush(struct drm_crtc *crtc)
 
 	DBG("%s: flush=%08x", mdp4_crtc->name, flush);
 
+	mdp4_crtc->flushed_mask = flush;
+
 	mdp4_write(mdp4_kms, REG_MDP4_OVERLAY_FLUSH, flush);
 }
 
@@ -537,6 +544,29 @@ static void mdp4_crtc_err_irq(struct mdp_irq *irq, uint32_t irqstatus)
 	crtc_flush(crtc);
 }
 
+static void mdp4_crtc_wait_for_flush_done(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
+	struct mdp4_kms *mdp4_kms = get_kms(crtc);
+	int ret;
+
+	ret = drm_crtc_vblank_get(crtc);
+	if (ret)
+		return;
+
+	ret = wait_event_timeout(dev->vblank[drm_crtc_index(crtc)].queue,
+		!(mdp4_read(mdp4_kms, REG_MDP4_OVERLAY_FLUSH) &
+			mdp4_crtc->flushed_mask),
+		msecs_to_jiffies(50));
+	if (ret <= 0)
+		dev_warn(dev->dev, "vblank time out, crtc=%d\n", mdp4_crtc->id);
+
+	mdp4_crtc->flushed_mask = 0;
+
+	drm_crtc_vblank_put(crtc);
+}
+
 uint32_t mdp4_crtc_vblank(struct drm_crtc *crtc)
 {
 	struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
@@ -600,6 +630,15 @@ void mdp4_crtc_set_intf(struct drm_crtc *crtc, enum mdp4_intf intf, int mixer)
 	mdp4_write(mdp4_kms, REG_MDP4_DISP_INTF_SEL, intf_sel);
 }
 
+void mdp4_crtc_wait_for_commit_done(struct drm_crtc *crtc)
+{
+	/* wait_for_flush_done is the only case for now.
+	 * Later we will have command mode CRTC to wait for
+	 * other event.
+	 */
+	mdp4_crtc_wait_for_flush_done(crtc);
+}
+
 static const char *dma_names[] = {
 		"DMA_P", "DMA_S", "DMA_E",
 };
diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
index 88a75cbc8f71..531e4acc2a87 100644
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
@@ -159,6 +159,12 @@ static void mdp4_complete_commit(struct msm_kms *kms, struct drm_atomic_state *s
 	mdp4_disable(mdp4_kms);
 }
 
+static void mdp4_wait_for_crtc_commit_done(struct msm_kms *kms,
+						struct drm_crtc *crtc)
+{
+	mdp4_crtc_wait_for_commit_done(crtc);
+}
+
 static long mdp4_round_pixclk(struct msm_kms *kms, unsigned long rate,
 		struct drm_encoder *encoder)
 {
@@ -197,6 +203,7 @@ static const struct mdp_kms_funcs kms_funcs = {
 		.disable_vblank  = mdp4_disable_vblank,
 		.prepare_commit  = mdp4_prepare_commit,
 		.complete_commit = mdp4_complete_commit,
+		.wait_for_crtc_commit_done = mdp4_wait_for_crtc_commit_done,
 		.get_format      = mdp_get_format,
 		.round_pixclk    = mdp4_round_pixclk,
 		.preclose        = mdp4_preclose,
diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h
index a537c078593b..c1ecb9d6bdef 100644
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h
@@ -206,6 +206,7 @@ uint32_t mdp4_crtc_vblank(struct drm_crtc *crtc);
 void mdp4_crtc_cancel_pending_flip(struct drm_crtc *crtc, struct drm_file *file);
 void mdp4_crtc_set_config(struct drm_crtc *crtc, uint32_t config);
 void mdp4_crtc_set_intf(struct drm_crtc *crtc, enum mdp4_intf intf, int mixer);
+void mdp4_crtc_wait_for_commit_done(struct drm_crtc *crtc);
 struct drm_crtc *mdp4_crtc_init(struct drm_device *dev,
 		struct drm_plane *plane, int id, int ovlp_id,
 		enum mdp4_dma dma_id);