drm/msm/dp: return correct connection status after suspend

During suspend, dp host controller and hpd block are disabled due to
both ahb and aux clock are disabled. Therefore hpd plug/unplug interrupts
will not be generated. At dp_pm_resume(), reinitialize both dp host
controller and hpd block so that hpd plug/unplug interrupts will be
generated and handled by driver so that hpd connection state is updated
correctly. This patch will fix link training flaky issues.

Changes in v2:
-- use container_of to cast correct dp_display_private pointer
at both dp_pm_suspend() and dp_pm_resume().

Changes in v3:
-- replace hpd_state atomic_t with u32

Changes in v4
-- call dp_display_host_deinit() at dp_pm_suspend()
-- call dp_display_host_init() at msm_dp_display_enable()
-- fix phy->init_count unbalance which causes link training failed

Changes in v5
-- add Fixes tag

Fixes: 8ede2ecc3e5e (drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets)
Tested-by: Stephen Boyd <[e-mail]>
Signed-off-by: Kuogee Hsieh <[e-mail]>
Signed-off-by: Rob Clark <[e-mail]>

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

···
 	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)
+{
+	struct dp_catalog_private *catalog = container_of(dp_catalog,
+				struct dp_catalog_private, dp_catalog);
+	u32 status;
+
+	status = dp_read_aux(catalog, REG_DP_DP_HPD_INT_STATUS);
+	status >>= DP_DP_HPD_STATE_STATUS_BITS_SHIFT;
+	status &= DP_DP_HPD_STATE_STATUS_BITS_MASK;
+
+	return status;
+}
+
 u32 dp_catalog_hpd_get_intr_status(struct dp_catalog *dp_catalog)
 {
 	struct dp_catalog_private *catalog = container_of(dp_catalog,

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

···
 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_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

···
 void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
 {
 	struct dp_ctrl_private *ctrl;
+	struct dp_io *dp_io;
+	struct phy *phy;
 
 	if (!dp_ctrl) {
 		DRM_ERROR("Invalid input data\n");
···
 	}
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
+	dp_io = &ctrl->parser->io;
+	phy = dp_io->phy;
 
 	dp_catalog_ctrl_enable_irq(ctrl->catalog, false);
+	phy_exit(phy);
 
 	DRM_DEBUG_DP("Host deinitialized successfully\n");
 }

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

···
 	/* event related only access by event thread */
 	struct mutex event_mutex;
 	wait_queue_head_t event_q;
-	atomic_t hpd_state;
+	u32 hpd_state;
 	u32 event_pndx;
 	u32 event_gndx;
 	struct dp_event event_list[DP_EVENT_Q_MAX];
 	spinlock_t event_lock;
-
-	struct completion resume_comp;
 
 	struct dp_audio *audio;
 };
···
 	dp->core_initialized = true;
 }
 
+static void dp_display_host_deinit(struct dp_display_private *dp)
+{
+	if (!dp->core_initialized) {
+		DRM_DEBUG_DP("DP core not initialized\n");
+		return;
+	}
+
+	dp_ctrl_host_deinit(dp->ctrl);
+	dp_aux_deinit(dp->aux);
+	dp_power_deinit(dp->power);
+
+	dp->core_initialized = false;
+}
+
 static int dp_display_usbpd_configure_cb(struct device *dev)
 {
 	int rc = 0;
···
 
 	mutex_lock(&dp->event_mutex);
 
-	state =  atomic_read(&dp->hpd_state);
+	state =  dp->hpd_state;
 	if (state == ST_SUSPEND_PENDING) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
···
 		return 0;
 	}
 
-	if (state == ST_SUSPENDED)
-		tout = DP_TIMEOUT_NONE;
-
-	atomic_set(&dp->hpd_state, ST_CONNECT_PENDING);
+	dp->hpd_state = ST_CONNECT_PENDING;
 
 	hpd->hpd_high = 1;
 
 	ret = dp_display_usbpd_configure_cb(&dp->pdev->dev);
 	if (ret) {	/* failed */
 		hpd->hpd_high = 0;
-		atomic_set(&dp->hpd_state, ST_DISCONNECTED);
+		dp->hpd_state = ST_DISCONNECTED;
 	}
 
 	/* start sanity checking */
···
 
 	mutex_lock(&dp->event_mutex);
 
-	state =  atomic_read(&dp->hpd_state);
+	state = dp->hpd_state;
 	if (state == ST_CONNECT_PENDING) {
 		dp_display_enable(dp, 0);
-		atomic_set(&dp->hpd_state, ST_CONNECTED);
+		dp->hpd_state = ST_CONNECTED;
 	}
 
 	mutex_unlock(&dp->event_mutex);
···
 
 	mutex_lock(&dp->event_mutex);
 
-	state = atomic_read(&dp->hpd_state);
+	state = dp->hpd_state;
 	if (state == ST_SUSPEND_PENDING) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
···
 		return 0;
 	}
 
-	atomic_set(&dp->hpd_state, ST_DISCONNECT_PENDING);
+	dp->hpd_state = ST_DISCONNECT_PENDING;
 
 	/* disable HPD plug interrupt until disconnect is done */
 	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK
···
 
 	mutex_lock(&dp->event_mutex);
 
-	state =  atomic_read(&dp->hpd_state);
+	state =  dp->hpd_state;
 	if (state == ST_DISCONNECT_PENDING) {
 		dp_display_disable(dp, 0);
-		atomic_set(&dp->hpd_state, ST_DISCONNECTED);
+		dp->hpd_state = ST_DISCONNECTED;
 	}
 
 	mutex_unlock(&dp->event_mutex);
···
 	mutex_lock(&dp->event_mutex);
 
 	/* irq_hpd can happen at either connected or disconnected state */
-	state =  atomic_read(&dp->hpd_state);
+	state =  dp->hpd_state;
 	if (state == ST_SUSPEND_PENDING) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
···
 
 	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;
 
-	/* complete resume_comp regardless it is armed or not */
-	complete(&dp->resume_comp);
 	return rc;
 }
 
···
 	struct msm_dp *dp_display;
 
 	dp_display = g_dp_display;
-
-	if (!dp_display->power_on)
-		return -EINVAL;
 
 	/* wait only if audio was enabled */
 	if (dp_display->audio_enabled) {
···
 	}
 
 	mutex_init(&dp->event_mutex);
-
-	init_completion(&dp->resume_comp);
-
 	g_dp_display = &dp->dp_display;
 
 	/* Store DP audio handle inside DP display */
···
 
 static int dp_pm_resume(struct device *dev)
 {
+	struct platform_device *pdev = to_platform_device(dev);
+	struct msm_dp *dp_display = platform_get_drvdata(pdev);
+	struct dp_display_private *dp;
+	u32 status;
+
+	dp = container_of(dp_display, struct dp_display_private, dp_display);
+
+	mutex_lock(&dp->event_mutex);
+
+	/* start from disconnected state */
+	dp->hpd_state = ST_DISCONNECTED;
+
+	/* turn on dp ctrl/phy */
+	dp_display_host_init(dp);
+
+	dp_catalog_ctrl_hpd_config(dp->catalog);
+
+	status = dp_catalog_hpd_get_state_status(dp->catalog);
+
+	if (status) {
+		dp->dp_display.is_connected = true;
+	} else {
+		dp->dp_display.is_connected = false;
+		/* make sure next resume host_init be called */
+		dp->core_initialized = false;
+	}
+
+	mutex_unlock(&dp->event_mutex);
+
 	return 0;
 }
 
 static int dp_pm_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
-	struct dp_display_private *dp = platform_get_drvdata(pdev);
+	struct msm_dp *dp_display = platform_get_drvdata(pdev);
+	struct dp_display_private *dp;
 
-	if (!dp) {
-		DRM_ERROR("DP driver bind failed. Invalid driver data\n");
-		return -EINVAL;
-	}
+	dp = container_of(dp_display, struct dp_display_private, dp_display);
 
-	atomic_set(&dp->hpd_state, ST_SUSPENDED);
+	mutex_lock(&dp->event_mutex);
+
+	if (dp->core_initialized == true)
+		dp_display_host_deinit(dp);
+
+	dp->hpd_state = ST_SUSPENDED;
+
+	mutex_unlock(&dp->event_mutex);
 
 	return 0;
 }
···
 	return 0;
 }
 
-static int dp_display_wait4resume_done(struct dp_display_private *dp)
-{
-	int ret = 0;
-
-	reinit_completion(&dp->resume_comp);
-	if (!wait_for_completion_timeout(&dp->resume_comp,
-				WAIT_FOR_RESUME_TIMEOUT_JIFFIES)) {
-		DRM_ERROR("wait4resume_done timedout\n");
-		ret = -ETIMEDOUT;
-	}
-	return ret;
-}
-
 int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 {
 	int rc = 0;
···
 	}
 
 	mutex_lock(&dp_display->event_mutex);
+
+	dp_del_event(dp_display, EV_CONNECT_PENDING_TIMEOUT);
 
 	rc = dp_display_set_mode(dp, &dp_display->dp_mode);
 	if (rc) {
···
 		return rc;
 	}
 
-	state =  atomic_read(&dp_display->hpd_state);
-	if (state == ST_SUSPENDED) {
-		/* start link training */
-		dp_add_event(dp_display, EV_HPD_PLUG_INT, 0, 0);
-		mutex_unlock(&dp_display->event_mutex);
+	state =  dp_display->hpd_state;
 
-		/* wait until dp interface is up */
-		goto resume_done;
-	}
+	if (state == ST_SUSPEND_PENDING)
+		dp_display_host_init(dp_display);
 
 	dp_display_enable(dp_display, 0);
 
···
 		dp_display_unprepare(dp);
 	}
 
-	dp_del_event(dp_display, EV_CONNECT_PENDING_TIMEOUT);
-
 	if (state == ST_SUSPEND_PENDING)
 		dp_add_event(dp_display, EV_IRQ_HPD_INT, 0, 0);
 
 	/* completed connection */
-	atomic_set(&dp_display->hpd_state, ST_CONNECTED);
+	dp_display->hpd_state = ST_CONNECTED;
 
 	mutex_unlock(&dp_display->event_mutex);
 
-	return rc;
-
-resume_done:
-	dp_display_wait4resume_done(dp_display);
 	return rc;
 }
 
···
 
 	mutex_lock(&dp_display->event_mutex);
 
+	dp_del_event(dp_display, EV_DISCONNECT_PENDING_TIMEOUT);
+
 	dp_display_disable(dp_display, 0);
 
 	rc = dp_display_unprepare(dp);
 	if (rc)
 		DRM_ERROR("DP display unprepare failed, rc=%d\n", rc);
 
-	dp_del_event(dp_display, EV_DISCONNECT_PENDING_TIMEOUT);
-
-	state =  atomic_read(&dp_display->hpd_state);
+	state =  dp_display->hpd_state;
 	if (state == ST_DISCONNECT_PENDING) {
 		/* completed disconnection */
-		atomic_set(&dp_display->hpd_state, ST_DISCONNECTED);
+		dp_display->hpd_state = ST_DISCONNECTED;
 	} else {
-		atomic_set(&dp_display->hpd_state, ST_SUSPEND_PENDING);
+		dp_display->hpd_state = ST_SUSPEND_PENDING;
 	}
 
 	mutex_unlock(&dp_display->event_mutex);

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

···
 #define DP_DP_IRQ_HPD_INT_ACK			(0x00000002)
 #define DP_DP_HPD_REPLUG_INT_ACK		(0x00000004)
 #define DP_DP_HPD_UNPLUG_INT_ACK		(0x00000008)
+#define DP_DP_HPD_STATE_STATUS_BITS_MASK	(0x0000000F)
+#define DP_DP_HPD_STATE_STATUS_BITS_SHIFT	(0x1C)
 
 #define REG_DP_DP_HPD_INT_MASK			(0x0000000C)
 #define DP_DP_HPD_PLUG_INT_MASK			(0x00000001)