disp: msm: dp: add error handling for host init failures

Add error handling mechanism in host init function to take necessary
action upon failure. For example, power init can fail if we try to
do host_init in between PM suspend. In this case sink sends an hpd
irq with hpd_high equals to 0 and hpd_high equals to 1, after which
ADSP sends the events to DP driver. Now as apps core is in PM suspend
all the devices are put to suspend state and cannot be resumed if
their disable_depth is greater than 1. When driver tries to process
the hpd_high equals to 1 and does host_init in between PM suspend,
it sometimes leads to power init module failure. Inadequate handling
of host init failure as described can lead to a NOC error.

Change-Id: I23eff28e137a18b43eef204fbccc695b743cf726
Signed-off-by: Rajat Gupta <rajatgu@codeaurora.org>
Signed-off-by: Sankeerth Billakanti <sbillaka@codeaurora.org>

msm/dp/dp_display.c

@@ -1003,14 +1003,15 @@ static void dp_display_process_mst_hpd_high(struct dp_display_private *dp,
 	DP_MST_DEBUG("mst_hpd_high. mst_active:%d\n", dp->mst.mst_active);
 }
 
-static void dp_display_host_init(struct dp_display_private *dp)
+static int dp_display_host_init(struct dp_display_private *dp)
 {
 	bool flip = false;
 	bool reset;
+	int rc = 0;
 
 	if (dp_display_state_is(DP_STATE_INITIALIZED)) {
 		dp_display_state_log("[already initialized]");
-		return;
+		return rc;
 	}
 
 	if (dp->hpd->orientation == ORIENTATION_CC2)
@@ -1018,9 +1019,21 @@ static void dp_display_host_init(struct dp_display_private *dp)
 
 	reset = dp->debug->sim_mode ? false : !dp->hpd->multi_func;
 
-	dp->power->init(dp->power, flip);
+	rc = dp->power->init(dp->power, flip);
+	if (rc) {
+		DP_WARN("Power init failed.\n");
+		SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_CASE1, dp->state);
+		return rc;
+	}
+
 	dp->hpd->host_init(dp->hpd, &dp->catalog->hpd);
-	dp->ctrl->init(dp->ctrl, flip, reset);
+	rc = dp->ctrl->init(dp->ctrl, flip, reset);
+	if (rc) {
+		DP_WARN("Ctrl init Failed.\n");
+		SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_CASE2, dp->state);
+		goto error_ctrl;
+	}
+
 	enable_irq(dp->irq);
 	dp_display_abort_hdcp(dp, false);
 
@@ -1028,6 +1041,12 @@ static void dp_display_host_init(struct dp_display_private *dp)
 
 	/* log this as it results from user action of cable connection */
 	DP_INFO("[OK]\n");
+	return rc;
+
+error_ctrl:
+	dp->hpd->host_deinit(dp->hpd, &dp->catalog->hpd);
+	dp->power->deinit(dp->power);
+	return rc;
 }
 
 static void dp_display_host_ready(struct dp_display_private *dp)
@@ -1148,7 +1167,24 @@ static int dp_display_process_hpd_high(struct dp_display_private *dp)
 	 */
 	if (dp_display_state_is(DP_STATE_SRC_PWRDN) &&
 			dp_display_state_is(DP_STATE_CONFIGURED)) {
-		dp_display_host_init(dp);
+		rc = dp_display_host_init(dp);
+		if (rc) {
+			DP_WARN("Host init Failed");
+			if (!dp_display_state_is(DP_STATE_SUSPENDED)) {
+				/*
+				 * If not suspended no point of going forward if
+				 * resource is not enabled.
+				 */
+				dp_display_state_remove(DP_STATE_CONNECTED);
+			}
+			goto end;
+		}
+
+		/*
+		 * If device is suspended and host_init fails, there is
+		 * one more chance for host init to happen in prepare which
+		 * is why DP_STATE_SRC_PWRDN is removed only at success.
+		 */
 		dp_display_state_remove(DP_STATE_SRC_PWRDN);
 	}
 
@@ -1326,7 +1362,12 @@ static int dp_display_usbpd_configure_cb(struct device *dev)
 	dp_display_state_remove(DP_STATE_ABORTED);
 	dp_display_state_add(DP_STATE_CONFIGURED);
 
-	dp_display_host_init(dp);
+	rc = dp_display_host_init(dp);
+	if (rc) {
+		DP_ERR("Host init Failed");
+		mutex_unlock(&dp->session_lock);
+		return rc;
+	}
 
 	/* check for hpd high */
 	if (dp->hpd->hpd_high)
@@ -2119,7 +2160,23 @@ static int dp_display_prepare(struct dp_display *dp_display, void *panel)
 	 */
 	if (dp_display_state_is(DP_STATE_SRC_PWRDN) &&
 			dp_display_state_is(DP_STATE_CONFIGURED)) {
-		dp_display_host_init(dp);
+		rc = dp_display_host_init(dp);
+		if (rc) {
+			/*
+			 * Skip all the events that are similar to abort case, just that
+			 * the stream clks should be enabled so that no commit failure can
+			 * be seen.
+			 */
+			DP_ERR("Host init failed.\n");
+			goto end;
+		}
+
+		/*
+		 * Remove DP_STATE_SRC_PWRDN flag on successful host_init to
+		 * prevent cases such as below.
+		 * 1. MST stream 1 failed to do host init then stream 2 can retry again.
+		 * 2. Resume path fails, now sink sends hpd_high=0 and hpd_high=1.
+		 */
 		dp_display_state_remove(DP_STATE_SRC_PWRDN);
 	}