[PATCH v4 19/39] drm/msm/dp: Add support to enable MST in mainlink control

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

From: Abhinav Kumar <quic_abhinavk@quicinc.com>

Add support to program the MST enable bit in the mainlink control
register when an MST session is active or being disabled.

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_ctrl.c | 17 +++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_reg.h  |  4 ++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 6f25145ef214..9513de81abc4 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -255,6 +255,19 @@ int msm_dp_ctrl_mst_send_act(struct msm_dp_ctrl *msm_dp_ctrl)
 	return 0;
 }
 
+static void msm_dp_ctrl_mst_config(struct msm_dp_ctrl_private *ctrl, bool enable)
+{
+	u32 mainlink_ctrl;
+
+	mainlink_ctrl = msm_dp_read_link(ctrl, 0, REG_DP_MAINLINK_CTRL);
+	if (enable)
+		mainlink_ctrl |= DP_MAINLINK_CTRL_MST_EN;
+	else
+		mainlink_ctrl &= ~DP_MAINLINK_CTRL_MST_EN;
+
+	msm_dp_write_link(ctrl, 0, REG_DP_MAINLINK_CTRL, mainlink_ctrl);
+}
+
 /*
  * NOTE: resetting DP controller will also clear any pending HPD related interrupts
  */
@@ -2669,6 +2682,9 @@ int msm_dp_ctrl_on_stream(struct msm_dp_ctrl *msm_dp_ctrl, struct msm_dp_panel *
 
 	msm_dp_ctrl_lane_mapping(ctrl);
 	msm_dp_setup_peripheral_flush(ctrl);
+	if (ctrl->mst_active)
+		msm_dp_ctrl_mst_config(ctrl, true);
+
 	if (msm_dp_panel->stream_id == DP_STREAM_0)
 		msm_dp_ctrl_config_ctrl_link(ctrl);
 
@@ -2726,6 +2742,7 @@ void msm_dp_ctrl_off_link(struct msm_dp_ctrl *msm_dp_ctrl)
 	phy = ctrl->phy;
 
 	msm_dp_ctrl_mainlink_disable(ctrl);
+	msm_dp_ctrl_mst_config(ctrl, false);
 
 	msm_dp_ctrl_reset(&ctrl->msm_dp_ctrl);
 
diff --git a/drivers/gpu/drm/msm/dp/dp_reg.h b/drivers/gpu/drm/msm/dp/dp_reg.h
index 237325d52dbd..87eaaefa014d 100644
--- a/drivers/gpu/drm/msm/dp/dp_reg.h
+++ b/drivers/gpu/drm/msm/dp/dp_reg.h
@@ -128,6 +128,10 @@
 #define DP_MAINLINK_FLUSH_MODE_UPDATE_SDP	FIELD_PREP(DP_MAINLINK_CTRL_FLUSH_MODE_MASK, 1)
 #define DP_MAINLINK_FLUSH_MODE_SDE_PERIPH_UPDATE	FIELD_PREP(DP_MAINLINK_CTRL_FLUSH_MODE_MASK, 3)
 #define DP_MAINLINK_FB_BOUNDARY_SEL		(0x02000000)
+#define DP_MAINLINK_CTRL_ECF_MODE		BIT(26)
+#define DP_MAINLINK_CTRL_MST_ACTIVE		BIT(8)
+#define DP_MAINLINK_CTRL_MST_EN			(DP_MAINLINK_CTRL_ECF_MODE | \
+						DP_MAINLINK_CTRL_MST_ACTIVE)
 
 #define REG_DP_STATE_CTRL			(0x00000004)
 #define DP_STATE_CTRL_LINK_TRAINING_PATTERN1	(0x00000001)

-- 
2.43.0