[PATCH v4] drm/msm/dp: stop event kernel thread when DP unbind

[Kuogee Hsieh]

Current DP driver implementation, event thread is kept running
after DP display is unbind. This patch fix this problem by disabling
DP irq and stop event thread to exit gracefully at dp_display_unbind().

Changes in v2:
-- start event thread at dp_display_bind()

Changes in v3:
-- disable all HDP interrupts at unbind
-- replace dp_hpd_event_setup() with dp_hpd_event_thread_start()
-- replace dp_hpd_event_stop() with dp_hpd_event_thread_stop()
-- move init_waitqueue_head(&dp->event_q) to probe()
-- move spin_lock_init(&dp->event_lock) to probe()

Changes in v4:
-- relocate both dp_display_bind() and dp_display_unbind() to bottom of file

Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 345 +++++++++++++++++++-----------------
 1 file changed, 182 insertions(+), 163 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 01453db..198df6b 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -113,6 +113,7 @@ struct dp_display_private {
 	u32 hpd_state;
 	u32 event_pndx;
 	u32 event_gndx;
+	struct task_struct *ev_tsk;
 	struct dp_event event_list[DP_EVENT_Q_MAX];
 	spinlock_t event_lock;
 
@@ -230,65 +231,6 @@ void dp_display_signal_audio_complete(struct msm_dp *dp_display)
 	complete_all(&dp->audio_comp);
 }
 
-static int dp_display_bind(struct device *dev, struct device *master,
-			   void *data)
-{
-	int rc = 0;
-	struct dp_display_private *dp = dev_get_dp_display_private(dev);
-	struct msm_drm_private *priv;
-	struct drm_device *drm;
-
-	drm = dev_get_drvdata(master);
-
-	dp->dp_display.drm_dev = drm;
-	priv = drm->dev_private;
-	priv->dp[dp->id] = &dp->dp_display;
-
-	rc = dp->parser->parse(dp->parser, dp->dp_display.connector_type);
-	if (rc) {
-		DRM_ERROR("device tree parsing failed\n");
-		goto end;
-	}
-
-	dp->dp_display.panel_bridge = dp->parser->panel_bridge;
-
-	dp->aux->drm_dev = drm;
-	rc = dp_aux_register(dp->aux);
-	if (rc) {
-		DRM_ERROR("DRM DP AUX register failed\n");
-		goto end;
-	}
-
-	rc = dp_power_client_init(dp->power);
-	if (rc) {
-		DRM_ERROR("Power client create failed\n");
-		goto end;
-	}
-
-	rc = dp_register_audio_driver(dev, dp->audio);
-	if (rc)
-		DRM_ERROR("Audio registration Dp failed\n");
-
-end:
-	return rc;
-}
-
-static void dp_display_unbind(struct device *dev, struct device *master,
-			      void *data)
-{
-	struct dp_display_private *dp = dev_get_dp_display_private(dev);
-	struct drm_device *drm = dev_get_drvdata(master);
-	struct msm_drm_private *priv = drm->dev_private;
-
-	dp_power_client_deinit(dp->power);
-	dp_aux_unregister(dp->aux);
-	priv->dp[dp->id] = NULL;
-}
-
-static const struct component_ops dp_display_comp_ops = {
-	.bind = dp_display_bind,
-	.unbind = dp_display_unbind,
-};
 
 static bool dp_display_is_ds_bridge(struct dp_panel *panel)
 {
@@ -1054,7 +996,7 @@ static int hpd_event_thread(void *data)
 
 	dp_priv = (struct dp_display_private *)data;
 
-	while (1) {
+	while (!kthread_should_stop()) {
 		if (timeout_mode) {
 			wait_event_timeout(dp_priv->event_q,
 				(dp_priv->event_pndx == dp_priv->event_gndx),
@@ -1132,14 +1074,6 @@ static int hpd_event_thread(void *data)
 	return 0;
 }
 
-static void dp_hpd_event_setup(struct dp_display_private *dp_priv)
-{
-	init_waitqueue_head(&dp_priv->event_q);
-	spin_lock_init(&dp_priv->event_lock);
-
-	kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler");
-}
-
 static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
 {
 	struct dp_display_private *dp = dev_id;
@@ -1237,65 +1171,6 @@ static const struct msm_dp_desc *dp_display_get_desc(struct platform_device *pde
 	return NULL;
 }
 
-static int dp_display_probe(struct platform_device *pdev)
-{
-	int rc = 0;
-	struct dp_display_private *dp;
-	const struct msm_dp_desc *desc;
-
-	if (!pdev || !pdev->dev.of_node) {
-		DRM_ERROR("pdev not found\n");
-		return -ENODEV;
-	}
-
-	dp = devm_kzalloc(&pdev->dev, sizeof(*dp), GFP_KERNEL);
-	if (!dp)
-		return -ENOMEM;
-
-	desc = dp_display_get_desc(pdev, &dp->id);
-	if (!desc)
-		return -EINVAL;
-
-	dp->pdev = pdev;
-	dp->name = "drm_dp";
-	dp->dp_display.connector_type = desc->connector_type;
-
-	rc = dp_init_sub_modules(dp);
-	if (rc) {
-		DRM_ERROR("init sub module failed\n");
-		return -EPROBE_DEFER;
-	}
-
-	mutex_init(&dp->event_mutex);
-
-	/* Store DP audio handle inside DP display */
-	dp->dp_display.dp_audio = dp->audio;
-
-	init_completion(&dp->audio_comp);
-
-	platform_set_drvdata(pdev, &dp->dp_display);
-
-	rc = component_add(&pdev->dev, &dp_display_comp_ops);
-	if (rc) {
-		DRM_ERROR("component add failed, rc=%d\n", rc);
-		dp_display_deinit_sub_modules(dp);
-	}
-
-	return rc;
-}
-
-static int dp_display_remove(struct platform_device *pdev)
-{
-	struct dp_display_private *dp = dev_get_dp_display_private(&pdev->dev);
-
-	dp_display_deinit_sub_modules(dp);
-
-	component_del(&pdev->dev, &dp_display_comp_ops);
-	platform_set_drvdata(pdev, NULL);
-
-	return 0;
-}
-
 static int dp_pm_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
@@ -1398,40 +1273,6 @@ static void dp_pm_complete(struct device *dev)
 
 }
 
-static const struct dev_pm_ops dp_pm_ops = {
-	.suspend = dp_pm_suspend,
-	.resume =  dp_pm_resume,
-	.prepare = dp_pm_prepare,
-	.complete = dp_pm_complete,
-};
-
-static struct platform_driver dp_display_driver = {
-	.probe  = dp_display_probe,
-	.remove = dp_display_remove,
-	.driver = {
-		.name = "msm-dp-display",
-		.of_match_table = dp_dt_match,
-		.suppress_bind_attrs = true,
-		.pm = &dp_pm_ops,
-	},
-};
-
-int __init msm_dp_register(void)
-{
-	int ret;
-
-	ret = platform_driver_register(&dp_display_driver);
-	if (ret)
-		DRM_ERROR("Dp display driver register failed");
-
-	return ret;
-}
-
-void __exit msm_dp_unregister(void)
-{
-	platform_driver_unregister(&dp_display_driver);
-}
-
 void msm_dp_irq_postinstall(struct msm_dp *dp_display)
 {
 	struct dp_display_private *dp;
@@ -1441,8 +1282,6 @@ void msm_dp_irq_postinstall(struct msm_dp *dp_display)
 
 	dp = container_of(dp_display, struct dp_display_private, dp_display);
 
-	dp_hpd_event_setup(dp);
-
 	dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
 }
 
@@ -1640,3 +1479,183 @@ void msm_dp_display_mode_set(struct msm_dp *dp, struct drm_encoder *encoder,
 	dp_display->dp_mode.h_active_low =
 		!!(dp_display->dp_mode.drm_mode.flags & DRM_MODE_FLAG_NHSYNC);
 }
+
+static int dp_hpd_event_thread_start(struct dp_display_private *dp_priv)
+{
+	dp_priv->ev_tsk = kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler");
+	if (IS_ERR(dp_priv->ev_tsk)) {
+		DRM_ERROR("failed to create DP event thread\n");
+		return PTR_ERR(dp_priv->ev_tsk);
+	}
+
+	return 0;
+}
+
+static void dp_hpd_event_thread_stop(struct dp_display_private *dp_priv)
+{
+	kthread_stop(dp_priv->ev_tsk);
+
+	/* reset event q to empty */
+	dp_priv->event_gndx = 0;
+	dp_priv->event_pndx = 0;
+}
+
+static int dp_display_bind(struct device *dev, struct device *master,
+			   void *data)
+{
+	int rc = 0;
+	struct dp_display_private *dp = dev_get_dp_display_private(dev);
+	struct msm_drm_private *priv;
+	struct drm_device *drm;
+
+	drm = dev_get_drvdata(master);
+
+	dp->dp_display.drm_dev = drm;
+	priv = drm->dev_private;
+	priv->dp[dp->id] = &dp->dp_display;
+
+	rc = dp->parser->parse(dp->parser, dp->dp_display.connector_type);
+	if (rc) {
+		DRM_ERROR("device tree parsing failed\n");
+		goto end;
+	}
+
+	dp->dp_display.panel_bridge = dp->parser->panel_bridge;
+
+	dp->aux->drm_dev = drm;
+	rc = dp_aux_register(dp->aux);
+	if (rc) {
+		DRM_ERROR("DRM DP AUX register failed\n");
+		goto end;
+	}
+
+	rc = dp_power_client_init(dp->power);
+	if (rc) {
+		DRM_ERROR("Power client create failed\n");
+		goto end;
+	}
+
+	rc = dp_register_audio_driver(dev, dp->audio);
+	if (rc)
+		DRM_ERROR("Audio registration Dp failed\n");
+
+	rc = dp_hpd_event_thread_start(dp);
+end:
+	return rc;
+}
+
+static void dp_display_unbind(struct device *dev, struct device *master,
+			      void *data)
+{
+	struct dp_display_private *dp = dev_get_dp_display_private(dev);
+	struct drm_device *drm = dev_get_drvdata(master);
+	struct msm_drm_private *priv = drm->dev_private;
+
+	/* disable all HPD interrupts */
+	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, false);
+	dp_hpd_event_thread_stop(dp);
+	dp_power_client_deinit(dp->power);
+	dp_aux_unregister(dp->aux);
+	priv->dp[dp->id] = NULL;
+}
+
+static const struct component_ops dp_display_comp_ops = {
+	.bind = dp_display_bind,
+	.unbind = dp_display_unbind,
+};
+
+static int dp_display_probe(struct platform_device *pdev)
+{
+	int rc = 0;
+	struct dp_display_private *dp;
+	const struct msm_dp_desc *desc;
+
+	if (!pdev || !pdev->dev.of_node) {
+		DRM_ERROR("pdev not found\n");
+		return -ENODEV;
+	}
+
+	dp = devm_kzalloc(&pdev->dev, sizeof(*dp), GFP_KERNEL);
+	if (!dp)
+		return -ENOMEM;
+
+	desc = dp_display_get_desc(pdev, &dp->id);
+	if (!desc)
+		return -EINVAL;
+
+	dp->pdev = pdev;
+	dp->name = "drm_dp";
+	dp->dp_display.connector_type = desc->connector_type;
+
+	rc = dp_init_sub_modules(dp);
+	if (rc) {
+		DRM_ERROR("init sub module failed\n");
+		return -EPROBE_DEFER;
+	}
+
+	/* setup event q */
+	mutex_init(&dp->event_mutex);
+	init_waitqueue_head(&dp->event_q);
+	spin_lock_init(&dp->event_lock);
+
+	/* Store DP audio handle inside DP display */
+	dp->dp_display.dp_audio = dp->audio;
+
+	init_completion(&dp->audio_comp);
+
+	platform_set_drvdata(pdev, &dp->dp_display);
+
+	rc = component_add(&pdev->dev, &dp_display_comp_ops);
+	if (rc) {
+		DRM_ERROR("component add failed, rc=%d\n", rc);
+		dp_display_deinit_sub_modules(dp);
+	}
+
+	return rc;
+}
+
+static int dp_display_remove(struct platform_device *pdev)
+{
+	struct dp_display_private *dp = dev_get_dp_display_private(&pdev->dev);
+
+	dp_display_deinit_sub_modules(dp);
+
+	component_del(&pdev->dev, &dp_display_comp_ops);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static const struct dev_pm_ops dp_pm_ops = {
+	.suspend = dp_pm_suspend,
+	.resume =  dp_pm_resume,
+	.prepare = dp_pm_prepare,
+	.complete = dp_pm_complete,
+};
+
+static struct platform_driver dp_display_driver = {
+	.probe  = dp_display_probe,
+	.remove = dp_display_remove,
+	.driver = {
+		.name = "msm-dp-display",
+		.of_match_table = dp_dt_match,
+		.suppress_bind_attrs = true,
+		.pm = &dp_pm_ops,
+	},
+};
+
+int __init msm_dp_register(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&dp_display_driver);
+	if (ret)
+		DRM_ERROR("Dp display driver register failed");
+
+	return ret;
+}
+
+void __exit msm_dp_unregister(void)
+{
+	platform_driver_unregister(&dp_display_driver);
+}
-- 
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