[PATCH v8 21/29] drm/msm/dp: add HPD callback for dp MST

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

From: Abhinav Kumar <quic_abhinavk@quicinc.com>

Add HPD callback for the MST module which shall be invoked from the
dp_display's HPD handler to perform MST specific operations in case
of HPD. In MST case, route the HPD messages to MST module.

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 21 ++++++++++++----
 drivers/gpu/drm/msm/dp/dp_mst_drm.c | 48 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_mst_drm.h |  1 +
 3 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index af8d22fd4fc5..b4e788d1f611 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -529,6 +529,11 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
+	if (dp->msm_dp_display.mst_active) {
+		msm_dp_mst_display_hpd_irq(&dp->msm_dp_display);
+		return 0;
+	}
+
 	/* check for any test request issued by sink */
 	rc = msm_dp_link_process_request(dp->link);
 	if (!rc) {
@@ -1078,10 +1083,10 @@ static irqreturn_t msm_dp_display_irq_thread(int irq, void *dev_id)
 		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
 				      connector_status_connected);
 
-	/* Send HPD as connected and distinguish it in the notifier */
 	if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK)
-		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
-				      connector_status_connected);
+		drm_bridge_hpd_notify_extra(dp->msm_dp_display.bridge,
+					    connector_status_connected,
+					    DRM_CONNECTOR_DP_IRQ_HPD);
 
 	ret = IRQ_HANDLED;
 
@@ -1318,9 +1323,15 @@ int msm_dp_mst_register(struct msm_dp *msm_dp_display)
 
 void msm_dp_mst_unregister(struct msm_dp *msm_dp_display)
 {
+	struct msm_dp_display_private *dp;
+
 	if (!msm_dp_display->msm_dp_mst)
 		return;
 
+	dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
+
+	/* HPD is disabled by drm_kms_helper_poll_fini() before KMS teardown. */
+	synchronize_irq(dp->irq);
 	msm_dp_mst_mgr_destroy(msm_dp_display);
 }
 
@@ -1755,7 +1766,7 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 	struct msm_dp_bridge *msm_dp_bridge = to_dp_bridge(bridge);
 	struct msm_dp *msm_dp_display = msm_dp_bridge->msm_dp_display;
 	struct msm_dp_display_private *dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
-	u32 hpd_link_status = 0;
+	u32 hpd_link_status;
 
 	if (pm_runtime_resume_and_get(&msm_dp_display->pdev->dev)) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
@@ -1778,7 +1789,7 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 		if (hpd_link_status == ISR_IRQ_HPD_PULSE_COUNT ||
 		    event == DRM_CONNECTOR_DP_IRQ_HPD)
 			msm_dp_irq_hpd_handle(dp);
-	} else {
+	} else if (status == connector_status_disconnected) {
 		msm_dp_hpd_unplug_handle(dp);
 	}
 
diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.c b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
index eae82e857c84..15405080107f 100644
--- a/drivers/gpu/drm/msm/dp/dp_mst_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
@@ -15,6 +15,8 @@
 #define to_dp_mst_connector(x) \
 		container_of((x), struct msm_dp_mst_connector, connector)
 
+#define MSM_DP_MST_HPD_IRQ_MAX_TRIES 30
+
 struct msm_dp_mst_connector {
 	struct drm_connector connector;
 	struct drm_dp_mst_port *mst_port;
@@ -36,6 +38,8 @@ struct msm_dp_mst {
 	u32 max_streams;
 	/* Serializes concurrent stream link-state access across streams. */
 	struct mutex mst_lock;
+	/* Serializes HPD IRQ handling between IRQ handler and poll_hpd_irq. */
+	struct mutex hpd_irq_lock;
 };
 
 static void dp_mst_connector_destroy(struct drm_connector *connector)
@@ -358,6 +362,40 @@ int msm_dp_mst_attach_encoder(struct msm_dp *dp_display, unsigned int stream_id,
 	return 0;
 }
 
+void msm_dp_mst_display_hpd_irq(struct msm_dp *dp_display)
+{
+	int rc;
+	struct msm_dp_mst *mst = dp_display->msm_dp_mst;
+	unsigned int esi_res = DP_SINK_COUNT_ESI + 1;
+	int i;
+
+	guard(mutex)(&mst->hpd_irq_lock);
+
+	for (i = 0; i < MSM_DP_MST_HPD_IRQ_MAX_TRIES; i++) {
+		u8 ack[8] = {};
+		u8 esi[4];
+		bool handled;
+
+		rc = drm_dp_dpcd_read_data(mst->dp_aux, DP_SINK_COUNT_ESI, esi, 4);
+		if (rc < 0) {
+			DRM_ERROR("DPCD sink status read failed, rlen=%d\n", rc);
+			return;
+		}
+
+		rc = drm_dp_mst_hpd_irq_handle_event(&mst->mst_mgr, esi, ack, &handled);
+		if (!handled)
+			break;
+
+		rc = drm_dp_dpcd_write_byte(mst->dp_aux, esi_res, ack[1]);
+		if (rc < 0) {
+			DRM_ERROR("DPCD esi_res failed. rc=%d\n", rc);
+			return;
+		}
+
+		drm_dp_mst_hpd_irq_send_new_request(&mst->mst_mgr);
+	}
+}
+
 static struct drm_encoder *
 msm_dp_mst_atomic_best_encoder(struct drm_connector *connector, struct drm_atomic_commit *state)
 {
@@ -473,8 +511,16 @@ msm_dp_mst_add_connector(struct drm_dp_mst_topology_mgr *mgr,
 	return NULL;
 }
 
+static void msm_dp_mst_poll_hpd_irq(struct drm_dp_mst_topology_mgr *mgr)
+{
+	struct msm_dp_mst *mst = container_of(mgr, struct msm_dp_mst, mst_mgr);
+
+	msm_dp_mst_display_hpd_irq(mst->msm_dp);
+}
+
 static const struct drm_dp_mst_topology_cbs msm_dp_mst_drm_cbs = {
 	.add_connector = msm_dp_mst_add_connector,
+	.poll_hpd_irq  = msm_dp_mst_poll_hpd_irq,
 };
 
 int msm_dp_mst_mgr_init(struct msm_dp *dp_display, struct msm_dp_link *link,
@@ -506,6 +552,7 @@ int msm_dp_mst_mgr_init(struct msm_dp *dp_display, struct msm_dp_link *link,
 	}
 
 	mutex_init(&mst->mst_lock);
+	mutex_init(&mst->hpd_irq_lock);
 	dp_display->msm_dp_mst = mst;
 	return 0;
 }
@@ -518,6 +565,7 @@ void msm_dp_mst_mgr_destroy(struct msm_dp *dp_display)
 		return;
 
 	drm_dp_mst_topology_mgr_destroy(&mst->mst_mgr);
+	mutex_destroy(&mst->hpd_irq_lock);
 	mutex_destroy(&mst->mst_lock);
 	dp_display->msm_dp_mst = NULL;
 	kfree(mst);
diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.h b/drivers/gpu/drm/msm/dp/dp_mst_drm.h
index 822d34cd6ff5..3bd3e66b4eac 100644
--- a/drivers/gpu/drm/msm/dp/dp_mst_drm.h
+++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.h
@@ -12,5 +12,6 @@ int msm_dp_mst_mgr_init(struct msm_dp *dp_display, struct msm_dp_link *link,
 void msm_dp_mst_mgr_destroy(struct msm_dp *dp_display);
 int msm_dp_mst_attach_encoder(struct msm_dp *dp_display, unsigned int stream_id,
 			      struct drm_encoder *encoder);
+void msm_dp_mst_display_hpd_irq(struct msm_dp *dp_display);
 
 #endif /* _DP_MST_DRM_H_ */

-- 
2.43.0