[RFC PATCH] drm/msm/dpu: Move TE setup to prepare_for_kickoff()

[Jessica Zhang]

Currently, DPU will enable TE during prepare_commit(). However, this
will cause issues when trying to read/write to register in
get_autorefresh_config(), because the core clock rates aren't set at
that time.

This used to work because phys_enc->hw_pp is only initialized in mode
set [1], so the first prepare_commit() will return before any register
read/write as hw_pp would be NULL.

However, when we try to implement support for INTF TE, we will run into
the clock issue described above as hw_intf will *not* be NULL on the
first prepare_commit(). This is because the initialization of
dpu_enc->hw_intf has been moved to dpu_encoder_setup() [2].

To avoid this issue, let's enable TE during prepare_for_kickoff()
instead as the core clock rates are guaranteed to be set then.

Depends on: "Implement tearcheck support on INTF block" [3]

[1] https://gitlab.freedesktop.org/drm/msm/-/blob/msm-next/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c#L1109
[2] https://gitlab.freedesktop.org/drm/msm/-/blob/msm-next/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c#L2339
[3] https://patchwork.freedesktop.org/series/112332/

Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>
---
 .../drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c  | 78 ++++++++++---------
 1 file changed, 43 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
index 279a0b7015ce..746250bce3d1 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
@@ -587,39 +587,6 @@ static void dpu_encoder_phys_cmd_destroy(struct dpu_encoder_phys *phys_enc)
 	kfree(cmd_enc);
 }
 
-static void dpu_encoder_phys_cmd_prepare_for_kickoff(
-		struct dpu_encoder_phys *phys_enc)
-{
-	struct dpu_encoder_phys_cmd *cmd_enc =
-			to_dpu_encoder_phys_cmd(phys_enc);
-	int ret;
-
-	if (!phys_enc->hw_pp) {
-		DPU_ERROR("invalid encoder\n");
-		return;
-	}
-	DRM_DEBUG_KMS("id:%u pp:%d pending_cnt:%d\n", DRMID(phys_enc->parent),
-		      phys_enc->hw_pp->idx - PINGPONG_0,
-		      atomic_read(&phys_enc->pending_kickoff_cnt));
-
-	/*
-	 * Mark kickoff request as outstanding. If there are more than one,
-	 * outstanding, then we have to wait for the previous one to complete
-	 */
-	ret = _dpu_encoder_phys_cmd_wait_for_idle(phys_enc);
-	if (ret) {
-		/* force pending_kickoff_cnt 0 to discard failed kickoff */
-		atomic_set(&phys_enc->pending_kickoff_cnt, 0);
-		DRM_ERROR("failed wait_for_idle: id:%u ret:%d pp:%d\n",
-			  DRMID(phys_enc->parent), ret,
-			  phys_enc->hw_pp->idx - PINGPONG_0);
-	}
-
-	DPU_DEBUG_CMDENC(cmd_enc, "pp:%d pending_cnt %d\n",
-			phys_enc->hw_pp->idx - PINGPONG_0,
-			atomic_read(&phys_enc->pending_kickoff_cnt));
-}
-
 static bool dpu_encoder_phys_cmd_is_ongoing_pptx(
 		struct dpu_encoder_phys *phys_enc)
 {
@@ -645,8 +612,7 @@ static bool dpu_encoder_phys_cmd_is_ongoing_pptx(
 	return false;
 }
 
-static void dpu_encoder_phys_cmd_prepare_commit(
-		struct dpu_encoder_phys *phys_enc)
+static void dpu_encoder_phys_cmd_enable_te(struct dpu_encoder_phys *phys_enc)
 {
 	struct dpu_encoder_phys_cmd *cmd_enc =
 		to_dpu_encoder_phys_cmd(phys_enc);
@@ -704,6 +670,48 @@ static void dpu_encoder_phys_cmd_prepare_commit(
 			 "disabled autorefresh\n");
 }
 
+static void dpu_encoder_phys_cmd_prepare_for_kickoff(
+		struct dpu_encoder_phys *phys_enc)
+{
+	struct dpu_encoder_phys_cmd *cmd_enc =
+			to_dpu_encoder_phys_cmd(phys_enc);
+	int ret;
+
+	if (!phys_enc->hw_pp) {
+		DPU_ERROR("invalid encoder\n");
+		return;
+	}
+
+
+	DRM_DEBUG_KMS("id:%u pp:%d pending_cnt:%d\n", DRMID(phys_enc->parent),
+		      phys_enc->hw_pp->idx - PINGPONG_0,
+		      atomic_read(&phys_enc->pending_kickoff_cnt));
+
+	/*
+	 * Mark kickoff request as outstanding. If there are more than one,
+	 * outstanding, then we have to wait for the previous one to complete
+	 */
+	ret = _dpu_encoder_phys_cmd_wait_for_idle(phys_enc);
+	if (ret) {
+		/* force pending_kickoff_cnt 0 to discard failed kickoff */
+		atomic_set(&phys_enc->pending_kickoff_cnt, 0);
+		DRM_ERROR("failed wait_for_idle: id:%u ret:%d pp:%d\n",
+			  DRMID(phys_enc->parent), ret,
+			  phys_enc->hw_pp->idx - PINGPONG_0);
+	}
+
+	dpu_encoder_phys_cmd_enable_te(phys_enc);
+
+	DPU_DEBUG_CMDENC(cmd_enc, "pp:%d pending_cnt %d\n",
+			phys_enc->hw_pp->idx - PINGPONG_0,
+			atomic_read(&phys_enc->pending_kickoff_cnt));
+}
+
+static void dpu_encoder_phys_cmd_prepare_commit(
+		struct dpu_encoder_phys *phys_enc)
+{
+}
+
 static int _dpu_encoder_phys_cmd_wait_for_ctl_start(
 		struct dpu_encoder_phys *phys_enc)
 {
-- 
2.39.1