[PATCH v6 24/29] 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 | 26 +++++++++++++++++-----
 drivers/gpu/drm/msm/dp/dp_mst_drm.c | 44 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_mst_drm.h |  1 +
 3 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index c015af868801..22b925277462 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -416,6 +416,9 @@ 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->plugged && dp->msm_dp_display.mst_active)
+		return 0;
+
 	guard(mutex)(&dp->plugged_lock);
 
 	ret = pm_runtime_resume_and_get(&pdev->dev);
@@ -506,12 +509,18 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp)
 {
 	u32 sink_request;
 	int rc = 0;
+	struct msm_dp *msm_dp_display = &dp->msm_dp_display;
 
 	/* irq_hpd can happen at either connected or disconnected state */
 	drm_dbg_dp(dp->drm_dev, "Before, type=%d, sink_count=%d\n",
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
+	if (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) {
@@ -1056,10 +1065,16 @@ 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);
+	/* Temporary until DRM IRQ support is finalized, then switch to
+	 * drm_bridge_hpd_notify().
+	 */
+	if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
+		if (dp->msm_dp_display.mst_active)
+			msm_dp_irq_hpd_handle(dp);
+		else
+			drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
+					      connector_status_connected);
+	}
 
 	ret = IRQ_HANDLED;
 
@@ -1717,7 +1732,8 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 			msm_dp_hpd_plug_handle(dp);
 		}
 	} else {
-		msm_dp_hpd_unplug_handle(dp);
+		if (hpd_link_status == ISR_DISCONNECTED)
+			msm_dp_hpd_unplug_handle(dp);
 	}
 
 	pm_runtime_put_sync(&msm_dp_display->pdev->dev);
diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.c b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
index 03f9c95ca686..2e625a7db981 100644
--- a/drivers/gpu/drm/msm/dp/dp_mst_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
@@ -35,6 +35,8 @@ 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;
 	struct msm_dp_link_info link_info;
 };
 
@@ -326,6 +328,39 @@ 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;
+	u8 ack[8] = {};
+	u8 esi[4];
+	unsigned int esi_res = DP_SINK_COUNT_ESI + 1;
+	bool handled;
+
+	guard(mutex)(&mst->hpd_irq_lock);
+
+	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;
+	}
+
+	drm_dbg_dp(dp_display->drm_dev, "MST HPD IRQ: esi=%*ph\n", 4, esi);
+
+	rc = drm_dp_mst_hpd_irq_handle_event(&mst->mst_mgr, esi, ack, &handled);
+
+	if (handled) {
+		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);
+	}
+	drm_dbg_dp(dp_display->drm_dev, "MST display hpd_irq handled:%d rc:%d\n", handled, rc);
+}
+
 static struct drm_encoder *
 msm_dp_mst_atomic_best_encoder(struct drm_connector *connector, struct drm_atomic_commit *state)
 {
@@ -441,8 +476,16 @@ 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, u32 max_streams, struct drm_dp_aux *drm_aux)
@@ -471,6 +514,7 @@ int msm_dp_mst_mgr_init(struct msm_dp *dp_display, u32 max_streams, struct drm_d
 	}
 
 	mutex_init(&mst->mst_lock);
+	mutex_init(&mst->hpd_irq_lock);
 	dp_display->msm_dp_mst = mst;
 	return 0;
 }
diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.h b/drivers/gpu/drm/msm/dp/dp_mst_drm.h
index 89f73b1db2e7..8546214cbca1 100644
--- a/drivers/gpu/drm/msm/dp/dp_mst_drm.h
+++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.h
@@ -10,5 +10,6 @@
 int msm_dp_mst_mgr_init(struct msm_dp *dp_display, u32 max_streams, struct drm_dp_aux *drm_aux);
 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