If the DP controller is capable of supporting multiple streams
then initialize the DP sink in MST mode by programming the DP_MSTM_CTRL
DPCD register to enable MST mode.
Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_display.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index e69cdfbbe10484e47475ef189849f8ff6628bd7a..033d238e956263c1212fce45aab01316ef341edb 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -380,6 +380,35 @@ static int msm_dp_display_send_hpd_notification(struct msm_dp_display_private *d
return 0;
}
+static void msm_dp_display_mst_init(struct msm_dp_display_private *dp)
+{
+ const unsigned long clear_mstm_ctrl_timeout_us = 100000;
+ u8 old_mstm_ctrl;
+ struct msm_dp *msm_dp = &dp->msm_dp_display;
+ int ret;
+
+ /* clear sink mst state */
+ drm_dp_dpcd_readb(dp->aux, DP_MSTM_CTRL, &old_mstm_ctrl);
+ drm_dp_dpcd_writeb(dp->aux, DP_MSTM_CTRL, 0);
+
+ /* add extra delay if MST state is not cleared */
+ if (old_mstm_ctrl) {
+ drm_dbg_dp(dp->drm_dev, "MSTM_CTRL is not cleared, wait %luus\n",
+ clear_mstm_ctrl_timeout_us);
+ usleep_range(clear_mstm_ctrl_timeout_us,
+ clear_mstm_ctrl_timeout_us + 1000);
+ }
+
+ ret = drm_dp_dpcd_writeb(dp->aux, DP_MSTM_CTRL,
+ DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
+ if (ret < 0) {
+ DRM_ERROR("sink mst enablement failed\n");
+ return;
+ }
+
+ msm_dp->mst_active = true;
+}
+
static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
{
struct drm_connector *connector = dp->msm_dp_display.connector;
@@ -414,6 +443,9 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
*/
msm_dp_link_psm_config(dp->link, &dp->panel->link_info, false);
+ if (dp->max_stream > DEFAULT_STREAM_COUNT && msm_dp_panel_read_mst_cap(dp->panel))
+ msm_dp_display_mst_init(dp);
+
msm_dp_link_reset_phy_params_vx_px(dp->link);
rc = msm_dp_ctrl_on_link(dp->ctrl, dp_display->mst_active);
if (rc) {
--
2.34.1
