[PATCH v4 9/9] drm/msm/dp: turn link_ready into plugged

[Dmitry Baryshkov]

Tracking when the DP link is ready isn't that useful from the driver
point of view. It doesn't provide a direct information if the device
should be suspended, etc. Replace it with the 'plugged' boolean, which
is set when the driver knows that there is DPRX plugged.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 94 ++++++++++++++++++++++---------------
 drivers/gpu/drm/msm/dp/dp_display.h |  1 -
 drivers/gpu/drm/msm/dp/dp_drm.c     | 41 ++--------------
 3 files changed, 61 insertions(+), 75 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index a1fb9c62bb0e..4e3664f9e5e5 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -53,6 +53,9 @@ struct msm_dp_display_private {
 	bool phy_initialized;
 	bool audio_supported;
 
+	struct mutex plugged_lock;
+	bool plugged;
+
 	struct drm_device *drm_dev;
 
 	struct drm_dp_aux *aux;
@@ -284,8 +287,6 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 						 dp->panel->dpcd,
 						 dp->panel->downstream_ports);
 
-	dp->msm_dp_display.link_ready = true;
-
 	dp->msm_dp_display.psr_supported = dp->panel->psr_cap.version && psr_enabled;
 
 	dp->audio_supported = info->has_audio;
@@ -303,7 +304,7 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 	return rc;
 }
 
-static void msm_dp_display_host_phy_init(struct msm_dp_display_private *dp)
+static bool msm_dp_display_host_phy_init(struct msm_dp_display_private *dp)
 {
 	drm_dbg_dp(dp->drm_dev, "type=%d core_init=%d phy_init=%d\n",
 		dp->msm_dp_display.connector_type, dp->core_initialized,
@@ -312,7 +313,10 @@ static void msm_dp_display_host_phy_init(struct msm_dp_display_private *dp)
 	if (!dp->phy_initialized) {
 		msm_dp_ctrl_phy_init(dp->ctrl);
 		dp->phy_initialized = true;
+		return true;
 	}
+
+	return false;
 }
 
 static void msm_dp_display_host_phy_exit(struct msm_dp_display_private *dp)
@@ -366,14 +370,6 @@ static int msm_dp_display_handle_irq_hpd(struct msm_dp_display_private *dp)
 	u32 sink_request = dp->link->sink_request;
 
 	drm_dbg_dp(dp->drm_dev, "%d\n", sink_request);
-	if (!dp->msm_dp_display.link_ready) {
-		if (sink_request & DP_LINK_STATUS_UPDATED) {
-			drm_dbg_dp(dp->drm_dev, "Disconnected sink_request: %d\n",
-							sink_request);
-			DRM_ERROR("Disconnected, no DP_LINK_STATUS_UPDATED\n");
-			return -EINVAL;
-		}
-	}
 
 	msm_dp_ctrl_handle_sink_request(dp->ctrl);
 
@@ -392,11 +388,11 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	if (dp->msm_dp_display.link_ready)
-		return 0;
+	mutex_lock(&dp->plugged_lock);
 
 	ret = pm_runtime_resume_and_get(&pdev->dev);
 	if (ret) {
+		mutex_unlock(&dp->plugged_lock);
 		DRM_ERROR("failed to pm_runtime_resume\n");
 		return ret;
 	}
@@ -406,18 +402,16 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 	msm_dp_display_host_phy_init(dp);
 
 	ret = msm_dp_display_process_hpd_high(dp);
-	if (ret) {	/* link train failed */
-		dp->msm_dp_display.link_ready = false;
-		msm_dp_aux_enable_xfers(dp->aux, false);
-		pm_runtime_put_sync(&pdev->dev);
-	}
 
 	drm_dbg_dp(dp->drm_dev, "After, type=%d sink_count=%d\n",
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	/* uevent will complete connection part */
-	return 0;
+	dp->plugged = true;
+
+	mutex_unlock(&dp->plugged_lock);
+
+	return ret;
 };
 
 static void msm_dp_display_handle_plugged_change(struct msm_dp *msm_dp_display,
@@ -446,8 +440,12 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	if (!dp->msm_dp_display.link_ready)
+	mutex_lock(&dp->plugged_lock);
+	if (!dp->plugged) {
+		mutex_unlock(&dp->plugged_lock);
+
 		return 0;
+	}
 
 	/* triggered by irq_hdp with sink_count = 0 */
 	if (dp->link->sink_count == 0)
@@ -463,8 +461,6 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 						 dp->panel->dpcd,
 						 dp->panel->downstream_ports);
 
-	dp->msm_dp_display.link_ready = false;
-
 	/* signal the disconnect event early to ensure proper teardown */
 	msm_dp_display_handle_plugged_change(&dp->msm_dp_display, false);
 
@@ -472,8 +468,12 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	/* uevent will complete disconnection part */
-	pm_runtime_put_sync(&pdev->dev);
+	if (dp->plugged) {
+		pm_runtime_put_sync(&pdev->dev);
+		dp->plugged = false;
+	}
+	mutex_unlock(&dp->plugged_lock);
+
 	return 0;
 }
 
@@ -820,41 +820,49 @@ enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
 	int status = connector_status_disconnected;
 	u8 dpcd[DP_RECEIVER_CAP_SIZE];
 	struct drm_dp_desc desc;
+	bool phy_deinit;
 
 	dp = to_dp_bridge(bridge)->msm_dp_display;
 
 	priv = container_of(dp, struct msm_dp_display_private, msm_dp_display);
 
-	if (!dp->link_ready)
-		return status;
-
+	mutex_lock(&priv->plugged_lock);
 	ret = pm_runtime_resume_and_get(&dp->pdev->dev);
 	if (ret) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
+		mutex_unlock(&priv->plugged_lock);
 		return status;
 	}
 
+	phy_deinit = msm_dp_display_host_phy_init(priv);
+
 	msm_dp_aux_enable_xfers(priv->aux, true);
 
 	ret = msm_dp_aux_is_link_connected(priv->aux);
-	if (!ret) {
+	DRM_DEBUG_DP("aux link status: %x\n", ret);
+	if (!priv->plugged && !ret) {
 		DRM_DEBUG_DP("aux not connected\n");
+		priv->plugged = false;
 		goto end;
 	}
 
 	ret = drm_dp_read_dpcd_caps(priv->aux, dpcd);
 	if (ret) {
 		DRM_DEBUG_DP("failed to read caps\n");
+		priv->plugged = false;
 		goto end;
 	}
 
 	ret = drm_dp_read_desc(priv->aux, &desc, drm_dp_is_branch(dpcd));
 	if (ret) {
 		DRM_DEBUG_DP("failed to read desc\n");
+		priv->plugged = false;
 		goto end;
 	}
 
 	status = connector_status_connected;
+	priv->plugged = true;
+
 	if (drm_dp_read_sink_count_cap(connector, dpcd, &desc)) {
 		int sink_count = drm_dp_read_sink_count(priv->aux);
 
@@ -865,7 +873,21 @@ enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
 	}
 
 end:
-	pm_runtime_put_sync(&dp->pdev->dev);
+	/*
+	 * If we detected the DPRX, leave the controller on so that it doesn't
+	 * loose the state.
+	 */
+	if (!priv->plugged) {
+		if (phy_deinit) {
+			msm_dp_aux_enable_xfers(priv->aux, false);
+			msm_dp_display_host_phy_exit(priv);
+		}
+
+		pm_runtime_put_sync(&dp->pdev->dev);
+	}
+
+	mutex_unlock(&priv->plugged_lock);
+
 	return status;
 }
 
@@ -1123,6 +1145,8 @@ static int msm_dp_display_probe(struct platform_device *pdev)
 		(dp->msm_dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);
 	dp->hpd_isr_status = 0;
 
+	mutex_init(&dp->plugged_lock);
+
 	rc = msm_dp_display_get_io(dp);
 	if (rc)
 		return rc;
@@ -1353,7 +1377,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 		return;
 	}
 
-	if (dp->link_ready && !dp->power_on) {
+	if (!dp->power_on) {
 		msm_dp_display_host_phy_init(msm_dp_display);
 		force_link_train = true;
 	}
@@ -1398,9 +1422,6 @@ void msm_dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
 	if (dp->is_edp)
 		msm_dp_hpd_unplug_handle(msm_dp_display);
 
-	if (!dp->link_ready)
-		drm_dbg_dp(dp->drm_dev, "type=%d is disconnected\n", dp->connector_type);
-
 	msm_dp_display_disable(msm_dp_display);
 
 	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
@@ -1498,9 +1519,8 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 
 	hpd_link_status = msm_dp_aux_is_link_connected(dp->aux);
 
-	drm_dbg_dp(dp->drm_dev, "type=%d link hpd_link_status=0x%x, link_ready=%d, status=%d\n",
-		   msm_dp_display->connector_type, hpd_link_status,
-		   msm_dp_display->link_ready, status);
+	drm_dbg_dp(dp->drm_dev, "type=%d link hpd_link_status=0x%x, status=%d\n",
+		   msm_dp_display->connector_type, hpd_link_status, status);
 
 	if (status == connector_status_connected) {
 		if (hpd_link_status == ISR_HPD_REPLUG_COUNT) {
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index d2d3d61eb0b0..0b65e16c790d 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -17,7 +17,6 @@ struct msm_dp {
 	struct drm_connector *connector;
 	struct drm_bridge *next_bridge;
 	struct drm_bridge *bridge;
-	bool link_ready;
 	bool audio_enabled;
 	bool power_on;
 	unsigned int connector_type;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index f935093c4df4..8dc0dabd275c 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -15,36 +15,6 @@
 #include "dp_audio.h"
 #include "dp_drm.h"
 
-static int msm_dp_bridge_atomic_check(struct drm_bridge *bridge,
-			    struct drm_bridge_state *bridge_state,
-			    struct drm_crtc_state *crtc_state,
-			    struct drm_connector_state *conn_state)
-{
-	struct msm_dp *dp;
-
-	dp = to_dp_bridge(bridge)->msm_dp_display;
-
-	drm_dbg_dp(dp->drm_dev, "link_ready = %s\n",
-		str_true_false(dp->link_ready));
-
-	/*
-	 * There is no protection in the DRM framework to check if the display
-	 * pipeline has been already disabled before trying to disable it again.
-	 * Hence if the sink is unplugged, the pipeline gets disabled, but the
-	 * crtc->active is still true. Any attempt to set the mode or manually
-	 * disable this encoder will result in the crash.
-	 *
-	 * TODO: add support for telling the DRM subsystem that the pipeline is
-	 * disabled by the hardware and thus all access to it should be forbidden.
-	 * After that this piece of code can be removed.
-	 */
-	if (bridge->ops & DRM_BRIDGE_OP_HPD)
-		return (dp->link_ready) ? 0 : -ENOTCONN;
-
-	return 0;
-}
-
-
 /**
  * msm_dp_bridge_get_modes - callback to add drm modes via drm_mode_probed_add()
  * @bridge: Poiner to drm bridge
@@ -62,12 +32,10 @@ static int msm_dp_bridge_get_modes(struct drm_bridge *bridge, struct drm_connect
 	dp = to_dp_bridge(bridge)->msm_dp_display;
 
 	/* pluggable case assumes EDID is read when HPD */
-	if (dp->link_ready) {
-		rc = msm_dp_display_get_modes(dp);
-		if (rc <= 0) {
-			DRM_ERROR("failed to get DP sink modes, rc=%d\n", rc);
-			return rc;
-		}
+	rc = msm_dp_display_get_modes(dp);
+	if (rc <= 0) {
+		DRM_ERROR("failed to get DP sink modes, rc=%d\n", rc);
+		return rc;
 	} else {
 		drm_dbg_dp(connector->dev, "No sink connected\n");
 	}
@@ -92,7 +60,6 @@ static const struct drm_bridge_funcs msm_dp_bridge_ops = {
 	.mode_valid   = msm_dp_bridge_mode_valid,
 	.get_modes    = msm_dp_bridge_get_modes,
 	.detect       = msm_dp_bridge_detect,
-	.atomic_check = msm_dp_bridge_atomic_check,
 	.hpd_enable   = msm_dp_bridge_hpd_enable,
 	.hpd_disable  = msm_dp_bridge_hpd_disable,
 	.hpd_notify   = msm_dp_bridge_hpd_notify,

-- 
2.47.3