drm/msm/mdp5: rework CTL START signal handling

For DSI cmd-mode and writeback, we need to write the CTL's START
register to kick things off, but we only want to do that once both
the encoder and the crtc have a chance to write their corresponding
flush bits.  The difficulty is that when there is a full modeset
(ie. encoder state has changed) we want to defer the start until
encoder->enable().  But if only plane's have changed, we want to do
this from crtc->commit().

The start_mask was a previous attempt to handle this, but it didn't
really do the right thing since atomic conversion.

Instead track in the crtc state that the start should be deferred,
set to try from encoder's (or in future writeback's) atomic_check().
This way the state is part of the atomic state, and rollback can
work properly if an atomic test fails.
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c

@@ -159,7 +159,7 @@ void mdp5_cmd_encoder_disable(struct drm_encoder *encoder)
 	pingpong_tearcheck_disable(encoder);
 
 	mdp5_ctl_set_encoder_state(ctl, pipeline, false);
-	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf));
+	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf), true);
 
 	bs_set(mdp5_cmd_enc, 0);
 
@@ -180,7 +180,7 @@ void mdp5_cmd_encoder_enable(struct drm_encoder *encoder)
 	if (pingpong_tearcheck_enable(encoder))
 		return;
 
-	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf));
+	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf), true);
 
 	mdp5_ctl_set_encoder_state(ctl, pipeline, true);
 

drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c

@@ -97,9 +97,13 @@ static u32 crtc_flush(struct drm_crtc *crtc, u32 flush_mask)
 	struct mdp5_crtc_state *mdp5_cstate = to_mdp5_crtc_state(crtc->state);
 	struct mdp5_ctl *ctl = mdp5_cstate->ctl;
 	struct mdp5_pipeline *pipeline = &mdp5_cstate->pipeline;
+	bool start = !mdp5_cstate->defer_start;
+
+	mdp5_cstate->defer_start = false;
 
 	DBG("%s: flush=%08x", crtc->name, flush_mask);
-	return mdp5_ctl_commit(ctl, pipeline, flush_mask);
+
+	return mdp5_ctl_commit(ctl, pipeline, flush_mask, start);
 }
 
 /*

drivers/gpu/drm/msm/disp/mdp5/mdp5_ctl.c

@@ -41,7 +41,9 @@ struct mdp5_ctl {
 	u32 status;
 
 	bool encoder_enabled;
-	uint32_t start_mask;
+
+	/* pending flush_mask bits */
+	u32 flush_mask;
 
 	/* REG_MDP5_CTL_*(<id>) registers access info + lock: */
 	spinlock_t hw_lock;
@@ -173,16 +175,8 @@ static void set_ctl_op(struct mdp5_ctl *ctl, struct mdp5_pipeline *pipeline)
 
 int mdp5_ctl_set_pipeline(struct mdp5_ctl *ctl, struct mdp5_pipeline *pipeline)
 {
-	struct mdp5_ctl_manager *ctl_mgr = ctl->ctlm;
-	struct mdp5_kms *mdp5_kms = get_kms(ctl_mgr);
+	struct mdp5_kms *mdp5_kms = get_kms(ctl->ctlm);
 	struct mdp5_interface *intf = pipeline->intf;
-	struct mdp5_hw_mixer *mixer = pipeline->mixer;
-	struct mdp5_hw_mixer *r_mixer = pipeline->r_mixer;
-
-	ctl->start_mask = mdp_ctl_flush_mask_lm(mixer->lm) |
-			  mdp_ctl_flush_mask_encoder(intf);
-	if (r_mixer)
-		ctl->start_mask |= mdp_ctl_flush_mask_lm(r_mixer->lm);
 
 	/* Virtual interfaces need not set a display intf (e.g.: Writeback) */
 	if (!mdp5_cfg_intf_is_virtual(intf->type))
@@ -198,7 +192,7 @@ static bool start_signal_needed(struct mdp5_ctl *ctl,
 {
 	struct mdp5_interface *intf = pipeline->intf;
 
-	if (!ctl->encoder_enabled || ctl->start_mask != 0)
+	if (!ctl->encoder_enabled)
 		return false;
 
 	switch (intf->type) {
@@ -227,25 +221,6 @@ static void send_start_signal(struct mdp5_ctl *ctl)
 	spin_unlock_irqrestore(&ctl->hw_lock, flags);
 }
 
-static void refill_start_mask(struct mdp5_ctl *ctl,
-			      struct mdp5_pipeline *pipeline)
-{
-	struct mdp5_interface *intf = pipeline->intf;
-	struct mdp5_hw_mixer *mixer = pipeline->mixer;
-	struct mdp5_hw_mixer *r_mixer = pipeline->r_mixer;
-
-	ctl->start_mask = mdp_ctl_flush_mask_lm(mixer->lm);
-	if (r_mixer)
-		ctl->start_mask |= mdp_ctl_flush_mask_lm(r_mixer->lm);
-
-	/*
-	 * Writeback encoder needs to program & flush
-	 * address registers for each page flip..
-	 */
-	if (intf->type == INTF_WB)
-		ctl->start_mask |= mdp_ctl_flush_mask_encoder(intf);
-}
-
 /**
  * mdp5_ctl_set_encoder_state() - set the encoder state
  *
@@ -268,7 +243,6 @@ int mdp5_ctl_set_encoder_state(struct mdp5_ctl *ctl,
 
 	if (start_signal_needed(ctl, pipeline)) {
 		send_start_signal(ctl);
-		refill_start_mask(ctl, pipeline);
 	}
 
 	return 0;
@@ -557,17 +531,14 @@ static void fix_for_single_flush(struct mdp5_ctl *ctl, u32 *flush_mask,
  */
 u32 mdp5_ctl_commit(struct mdp5_ctl *ctl,
 		    struct mdp5_pipeline *pipeline,
-		    u32 flush_mask)
+		    u32 flush_mask, bool start)
 {
 	struct mdp5_ctl_manager *ctl_mgr = ctl->ctlm;
 	unsigned long flags;
 	u32 flush_id = ctl->id;
 	u32 curr_ctl_flush_mask;
 
-	ctl->start_mask &= ~flush_mask;
-
-	VERB("flush_mask=%x, start_mask=%x, trigger=%x", flush_mask,
-			ctl->start_mask, ctl->pending_ctl_trigger);
+	VERB("flush_mask=%x, trigger=%x", flush_mask, ctl->pending_ctl_trigger);
 
 	if (ctl->pending_ctl_trigger & flush_mask) {
 		flush_mask |= MDP5_CTL_FLUSH_CTL;
@@ -582,6 +553,14 @@ u32 mdp5_ctl_commit(struct mdp5_ctl *ctl,
 
 	fix_for_single_flush(ctl, &flush_mask, &flush_id);
 
+	if (!start) {
+		ctl->flush_mask |= flush_mask;
+		return curr_ctl_flush_mask;
+	} else {
+		flush_mask |= ctl->flush_mask;
+		ctl->flush_mask = 0;
+	}
+
 	if (flush_mask) {
 		spin_lock_irqsave(&ctl->hw_lock, flags);
 		ctl_write(ctl, REG_MDP5_CTL_FLUSH(flush_id), flush_mask);
@@ -590,7 +569,6 @@ u32 mdp5_ctl_commit(struct mdp5_ctl *ctl,
 
 	if (start_signal_needed(ctl, pipeline)) {
 		send_start_signal(ctl);
-		refill_start_mask(ctl, pipeline);
 	}
 
 	return curr_ctl_flush_mask;

drivers/gpu/drm/msm/disp/mdp5/mdp5_ctl.h

@@ -78,7 +78,7 @@ u32 mdp_ctl_flush_mask_encoder(struct mdp5_interface *intf);
 
 /* @flush_mask: see CTL flush masks definitions below */
 u32 mdp5_ctl_commit(struct mdp5_ctl *ctl, struct mdp5_pipeline *pipeline,
-		    u32 flush_mask);
+		    u32 flush_mask, bool start);
 u32 mdp5_ctl_get_commit_status(struct mdp5_ctl *ctl);
 
 

drivers/gpu/drm/msm/disp/mdp5/mdp5_encoder.c

@@ -228,7 +228,7 @@ static void mdp5_vid_encoder_disable(struct drm_encoder *encoder)
 	spin_lock_irqsave(&mdp5_encoder->intf_lock, flags);
 	mdp5_write(mdp5_kms, REG_MDP5_INTF_TIMING_ENGINE_EN(intfn), 0);
 	spin_unlock_irqrestore(&mdp5_encoder->intf_lock, flags);
-	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf));
+	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf), true);
 
 	/*
 	 * Wait for a vsync so we know the ENABLE=0 latched before
@@ -262,7 +262,7 @@ static void mdp5_vid_encoder_enable(struct drm_encoder *encoder)
 	spin_lock_irqsave(&mdp5_encoder->intf_lock, flags);
 	mdp5_write(mdp5_kms, REG_MDP5_INTF_TIMING_ENGINE_EN(intfn), 1);
 	spin_unlock_irqrestore(&mdp5_encoder->intf_lock, flags);
-	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf));
+	mdp5_ctl_commit(ctl, pipeline, mdp_ctl_flush_mask_encoder(intf), true);
 
 	mdp5_ctl_set_encoder_state(ctl, pipeline, true);
 
@@ -319,6 +319,7 @@ static int mdp5_encoder_atomic_check(struct drm_encoder *encoder,
 
 	mdp5_cstate->ctl = ctl;
 	mdp5_cstate->pipeline.intf = intf;
+	mdp5_cstate->defer_start = true;
 
 	return 0;
 }

drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h

@@ -133,6 +133,14 @@ struct mdp5_crtc_state {
 	u32 pp_done_irqmask;
 
 	bool cmd_mode;
+
+	/* should we not write CTL[n].START register on flush?  If the
+	 * encoder has changed this is set to true, since encoder->enable()
+	 * is called after crtc state is committed, but we only want to
+	 * write the CTL[n].START register once.  This lets us defer
+	 * writing CTL[n].START until encoder->enable()
+	 */
+	bool defer_start;
 };
 #define to_mdp5_crtc_state(x) \
 		container_of(x, struct mdp5_crtc_state, base)

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

@@ -545,7 +545,7 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane,
 
 		ctl = mdp5_crtc_get_ctl(new_state->crtc);
 
-		mdp5_ctl_commit(ctl, pipeline, mdp5_plane_get_flush(plane));
+		mdp5_ctl_commit(ctl, pipeline, mdp5_plane_get_flush(plane), true);
 	}
 
 	*to_mdp5_plane_state(plane->state) =