drm/msm/dp: deinitialize mainlink if link training failed

DP compo phy have to be enable to start link training. When
link training failed phy need to be disabled so that next
link traning can be proceed smoothly at next plug in. This
patch de-initialize mainlink to disable phy if link training
failed. This prevent system crash due to
disp_cc_mdss_dp_link_intf_clk stuck at "off" state.  This patch
also perform checking power_on flag at dp_display_enable() and
dp_display_disable() to avoid crashing when unplug cable while
display is off.
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/dp/dp_catalog.c

@@ -572,7 +572,7 @@ void dp_catalog_ctrl_hpd_config(struct dp_catalog *dp_catalog)
 	dp_write_aux(catalog, REG_DP_DP_HPD_CTRL, DP_DP_HPD_CTRL_HPD_EN);
 }
 
-u32 dp_catalog_hpd_get_state_status(struct dp_catalog *dp_catalog)
+u32 dp_catalog_link_is_connected(struct dp_catalog *dp_catalog)
 {
 	struct dp_catalog_private *catalog = container_of(dp_catalog,
 				struct dp_catalog_private, dp_catalog);

drivers/gpu/drm/msm/dp/dp_catalog.h

@@ -97,7 +97,7 @@ void dp_catalog_ctrl_enable_irq(struct dp_catalog *dp_catalog, bool enable);
 void dp_catalog_hpd_config_intr(struct dp_catalog *dp_catalog,
 			u32 intr_mask, bool en);
 void dp_catalog_ctrl_hpd_config(struct dp_catalog *dp_catalog);
-u32 dp_catalog_hpd_get_state_status(struct dp_catalog *dp_catalog);
+u32 dp_catalog_link_is_connected(struct dp_catalog *dp_catalog);
 u32 dp_catalog_hpd_get_intr_status(struct dp_catalog *dp_catalog);
 void dp_catalog_ctrl_phy_reset(struct dp_catalog *dp_catalog);
 int dp_catalog_ctrl_update_vx_px(struct dp_catalog *dp_catalog, u8 v_level,

drivers/gpu/drm/msm/dp/dp_ctrl.c

@@ -1471,6 +1471,30 @@ static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
 	return ret;
 }
 
+static int dp_ctrl_deinitialize_mainlink(struct dp_ctrl_private *ctrl)
+{
+	struct dp_io *dp_io;
+	struct phy *phy;
+	int ret;
+
+	dp_io = &ctrl->parser->io;
+	phy = dp_io->phy;
+
+	dp_catalog_ctrl_mainlink_ctrl(ctrl->catalog, false);
+
+	dp_catalog_ctrl_reset(ctrl->catalog);
+
+	ret = dp_power_clk_enable(ctrl->power, DP_CTRL_PM, false);
+	if (ret) {
+		DRM_ERROR("Failed to disable link clocks. ret=%d\n", ret);
+	}
+
+	phy_power_off(phy);
+	phy_exit(phy);
+
+	return 0;
+}
+
 static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl)
 {
 	int ret = 0;
@@ -1651,8 +1675,7 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 	if (rc)
 		return rc;
 
-	while (--link_train_max_retries &&
-		!atomic_read(&ctrl->dp_ctrl.aborted)) {
+	while (--link_train_max_retries) {
 		rc = dp_ctrl_reinitialize_mainlink(ctrl);
 		if (rc) {
 			DRM_ERROR("Failed to reinitialize mainlink. rc=%d\n",
@@ -1667,6 +1690,10 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 			break;
 		} else if (training_step == DP_TRAINING_1) {
 			/* link train_1 failed */
+			if (!dp_catalog_link_is_connected(ctrl->catalog)) {
+				break;
+			}
+
 			rc = dp_ctrl_link_rate_down_shift(ctrl);
 			if (rc < 0) { /* already in RBR = 1.6G */
 				if (cr.lane_0_1 & DP_LANE0_1_CR_DONE) {
@@ -1686,6 +1713,10 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 			}
 		} else if (training_step == DP_TRAINING_2) {
 			/* link train_2 failed, lower lane rate */
+			if (!dp_catalog_link_is_connected(ctrl->catalog)) {
+				break;
+			}
+
 			rc = dp_ctrl_link_lane_down_shift(ctrl);
 			if (rc < 0) {
 				/* end with failure */
@@ -1706,6 +1737,11 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 	 */
 	if (rc == 0)  /* link train successfully */
 		dp_ctrl_push_idle(dp_ctrl);
+	else  {
+		/* link training failed */
+		dp_ctrl_deinitialize_mainlink(ctrl);
+		rc = -ECONNRESET;
+	}
 
 	return rc;
 }

drivers/gpu/drm/msm/dp/dp_display.c

@@ -529,6 +529,11 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
 	if (ret) {	/* link train failed */
 		hpd->hpd_high = 0;
 		dp->hpd_state = ST_DISCONNECTED;
+
+		if (ret == -ECONNRESET) { /* cable unplugged */
+			dp->core_initialized = false;
+		}
+
 	} else {
 		/* start sentinel checking in case of missing uevent */
 		dp_add_event(dp, EV_CONNECT_PENDING_TIMEOUT, 0, tout);
@@ -794,6 +799,11 @@ static int dp_display_enable(struct dp_display_private *dp, u32 data)
 
 	dp_display = g_dp_display;
 
+	if (dp_display->power_on) {
+		DRM_DEBUG_DP("Link already setup, return\n");
+		return 0;
+	}
+
 	rc = dp_ctrl_on_stream(dp->ctrl);
 	if (!rc)
 		dp_display->power_on = true;
@@ -826,6 +836,9 @@ static int dp_display_disable(struct dp_display_private *dp, u32 data)
 
 	dp_display = g_dp_display;
 
+	if (!dp_display->power_on)
+		return 0;
+
 	/* wait only if audio was enabled */
 	if (dp_display->audio_enabled) {
 		if (!wait_for_completion_timeout(&dp->audio_comp,
@@ -1198,7 +1211,7 @@ static int dp_pm_resume(struct device *dev)
 
 	dp_catalog_ctrl_hpd_config(dp->catalog);
 
-	status = dp_catalog_hpd_get_state_status(dp->catalog);
+	status = dp_catalog_link_is_connected(dp->catalog);
 
 	if (status)
 		dp->dp_display.is_connected = true;

drivers/gpu/drm/msm/dp/dp_panel.c

@@ -197,7 +197,7 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel,
 	if (!dp_panel->edid) {
 		DRM_ERROR("panel edid read failed\n");
 		/* check edid read fail is due to unplug */
-		if (!dp_catalog_hpd_get_state_status(panel->catalog)) {
+		if (!dp_catalog_link_is_connected(panel->catalog)) {
 			rc = -ETIMEDOUT;
 			goto end;
 		}