[PATCH v6 16/29] drm/msm/dp: add link_ready to manage link-level operations

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

In MST mode, multiple streams share the same DP link. Track a link_ready
state so msm_dp_display_prepare_link() runs only once per link and
repeated calls are skipped.

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 | 33 +++++++++++++++++++++++++--------
 drivers/gpu/drm/msm/dp/dp_display.h |  1 +
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 6103fa67f3ee..90e3d2c4ef47 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -638,6 +638,10 @@ int msm_dp_display_prepare_link(struct msm_dp *msm_dp_display)
 	if (msm_dp_display->is_edp)
 		msm_dp_hpd_plug_handle(dp);
 
+	/* Serialized by modeset lock or mst_lock. */
+	if (msm_dp_display->link_ready)
+		return 0;
+
 	rc = pm_runtime_resume_and_get(&msm_dp_display->pdev->dev);
 	if (rc) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
@@ -659,7 +663,11 @@ int msm_dp_display_prepare_link(struct msm_dp *msm_dp_display)
 		}
 	}
 
-	return msm_dp_ctrl_prepare_stream_on(dp->ctrl, dp->panel, force_link_train);
+	rc = msm_dp_ctrl_prepare_stream_on(dp->ctrl, dp->panel, force_link_train);
+	if (!rc)
+		msm_dp_display->link_ready = true;
+
+	return rc;
 }
 
 static int msm_dp_display_enable(struct msm_dp_display_private *dp,
@@ -1493,14 +1501,16 @@ void msm_dp_display_enable_helper(struct msm_dp *msm_dp_display, struct msm_dp_p
 
 	dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
 
-	rc = msm_dp_display_enable(dp, msm_dp_panel);
-	if (rc)
-		DRM_ERROR("DP display enable failed, rc=%d\n", rc);
+	if (msm_dp_display->link_ready) {
+		rc = msm_dp_display_enable(dp, msm_dp_panel);
+		if (rc)
+			DRM_ERROR("DP display enable failed, rc=%d\n", rc);
 
-	rc = msm_dp_display_post_enable(msm_dp_display);
-	if (rc) {
-		DRM_ERROR("DP display post enable failed, rc=%d\n", rc);
-		msm_dp_display_disable(dp, msm_dp_panel);
+		rc = msm_dp_display_post_enable(msm_dp_display);
+		if (rc) {
+			DRM_ERROR("DP display post enable failed, rc=%d\n", rc);
+			msm_dp_display_disable(dp, msm_dp_panel);
+		}
 	}
 
 	drm_dbg_dp(msm_dp_display->drm_dev, "type=%d Done\n", msm_dp_display->connector_type);
@@ -1543,6 +1553,11 @@ void msm_dp_display_unprepare(struct msm_dp *msm_dp_display)
 
 	dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
 
+	if (!msm_dp_display->link_ready) {
+		drm_dbg_dp(dp->drm_dev, "Link already setup, return\n");
+		return;
+	}
+
 	if (msm_dp_display->active_stream_cnt) {
 		drm_dbg_dp(dp->drm_dev, "stream still active, return\n");
 		return;
@@ -1561,6 +1576,8 @@ void msm_dp_display_unprepare(struct msm_dp *msm_dp_display)
 		msm_dp_display_host_phy_exit(dp);
 
 	pm_runtime_put_sync(&msm_dp_display->pdev->dev);
+
+	msm_dp_display->link_ready = false;
 }
 
 void msm_dp_display_atomic_post_disable_helper(struct msm_dp *dp, struct msm_dp_panel *msm_dp_panel)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index 9ecd5025fe4a..51eace1d1346 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -20,6 +20,7 @@ struct msm_dp {
 	bool audio_enabled;
 	u32 active_stream_cnt;
 	bool mst_active;
+	bool link_ready;
 	unsigned int connector_type;
 	bool is_edp;
 

-- 
2.43.0