disp: msm: sde: while timing engine enabling poll for active region

DCS commands triggered right after timing engine enable can conflict
with blanking period causing command transfer failures. Right after
timing engine enable poll for frame start and line count reaching
active region of display before any DCS commands.

Change-Id: Ia3967e01c3bb5bc82aa3549c300fa8335e00210c
Signed-off-by: Prabhanjan Kandula <quic_pkandula@quicinc.com>
Signed-off-by: Srihitha Tangudu <quic_tangudu@quicinc.com>

msm/sde/sde_encoder_phys_vid.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2015-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #define pr_fmt(fmt)	"[drm:%s:%d] " fmt, __func__, __LINE__
@@ -1080,12 +1081,47 @@ exit:
 	phys_enc->enable_state = SDE_ENC_DISABLED;
 }
 
+static int sde_encoder_phys_vid_poll_for_active_region(
+					struct sde_encoder_phys *phys_enc)
+{
+	struct sde_encoder_phys_vid *vid_enc;
+	struct intf_timing_params *timing;
+	struct drm_display_mode mode;
+	u32 line_cnt, v_inactive, poll_time_us, trial = 0;
+
+	if (!phys_enc || !phys_enc->hw_intf ||
+				!phys_enc->hw_intf->ops.get_line_count)
+		return -EINVAL;
+
+	vid_enc = to_sde_encoder_phys_vid(phys_enc);
+	timing = &vid_enc->timing_params;
+	mode = phys_enc->cached_mode;
+
+	/* if programmable fetch is not enabled return early */
+	if (!programmable_fetch_get_num_lines(vid_enc, timing, false))
+		return 0;
+
+	poll_time_us = DIV_ROUND_UP(1000000, mode.vrefresh) / MAX_POLL_CNT;
+	v_inactive = timing->v_front_porch + timing->v_back_porch +
+						timing->vsync_pulse_width;
+
+	do {
+		usleep_range(poll_time_us, poll_time_us + 5);
+		line_cnt = phys_enc->hw_intf->ops.get_line_count(
+							phys_enc->hw_intf);
+		trial++;
+	} while ((trial < MAX_POLL_CNT) || (line_cnt < v_inactive));
+
+	return (trial >= MAX_POLL_CNT) ? -ETIMEDOUT : 0;
+}
+
 static void sde_encoder_phys_vid_handle_post_kickoff(
 		struct sde_encoder_phys *phys_enc)
 {
 	unsigned long lock_flags;
 	struct sde_encoder_phys_vid *vid_enc;
 	u32 avr_mode;
+	u32 ret;
 
 	if (!phys_enc) {
 		SDE_ERROR("invalid encoder\n");
@@ -1108,6 +1144,11 @@ static void sde_encoder_phys_vid_handle_post_kickoff(
 				1);
 			spin_unlock_irqrestore(phys_enc->enc_spinlock,
 				lock_flags);
+			ret = sde_encoder_phys_vid_poll_for_active_region(
+								     phys_enc);
+			if (ret)
+				SDE_DEBUG_VIDENC(vid_enc,
+				       "poll for active failed ret:%d\n", ret);
 		}
 		phys_enc->enable_state = SDE_ENC_ENABLED;
 	}