[PATCH 05/17] drm/msm/dp: add an API to indicate if sink supports VSC SDP

[Paloma Arellano <quic_parellan@quicinc.com>]

YUV420 format is supported only in the VSC SDP packet and not through
MSA. Hence add an API which indicates the sink support which can be used
by the rest of the DP programming.

Signed-off-by: Paloma Arellano <quic_parellan@quicinc.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c |  3 ++-
 drivers/gpu/drm/msm/dp/dp_panel.c   | 35 +++++++++++++++++++++++++----
 drivers/gpu/drm/msm/dp/dp_panel.h   |  1 +
 3 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index ddac55f45a722..f6b3b6ca242f8 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1617,7 +1617,8 @@ void dp_bridge_mode_set(struct drm_bridge *drm_bridge,
 		!!(dp_display->dp_mode.drm_mode.flags & DRM_MODE_FLAG_NHSYNC);
 
 	dp_display->dp_mode.out_fmt_is_yuv_420 =
-		drm_mode_is_420_only(&dp->connector->display_info, adjusted_mode);
+		drm_mode_is_420_only(&dp->connector->display_info, adjusted_mode) &&
+		dp_panel_vsc_sdp_supported(dp_display->panel);
 
 	/* populate wide_bus_support to different layers */
 	dp_display->ctrl->wide_bus_en =
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 127f6af995cd1..af7820b6d35ec 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -17,6 +17,9 @@ struct dp_panel_private {
 	struct dp_link *link;
 	struct dp_catalog *catalog;
 	bool panel_on;
+	bool vsc_supported;
+	u8 major;
+	u8 minor;
 };
 
 static void dp_panel_read_psr_cap(struct dp_panel_private *panel)
@@ -43,9 +46,10 @@ static void dp_panel_read_psr_cap(struct dp_panel_private *panel)
 static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
 {
 	int rc;
+	ssize_t rlen;
 	struct dp_panel_private *panel;
 	struct dp_link_info *link_info;
-	u8 *dpcd, major, minor;
+	u8 *dpcd, rx_feature;
 
 	panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
 	dpcd = dp_panel->dpcd;
@@ -53,10 +57,19 @@ static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
 	if (rc)
 		return rc;
 
+	rlen = drm_dp_dpcd_read(panel->aux, DP_DPRX_FEATURE_ENUMERATION_LIST, &rx_feature, 1);
+	if (rlen != 1) {
+		panel->vsc_supported = false;
+		pr_debug("failed to read DP_DPRX_FEATURE_ENUMERATION_LIST\n");
+	} else {
+		panel->vsc_supported = !!(rx_feature & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED);
+		pr_debug("vsc=%d\n", panel->vsc_supported);
+	}
+
 	link_info = &dp_panel->link_info;
 	link_info->revision = dpcd[DP_DPCD_REV];
-	major = (link_info->revision >> 4) & 0x0f;
-	minor = link_info->revision & 0x0f;
+	panel->major = (link_info->revision >> 4) & 0x0f;
+	panel->minor = link_info->revision & 0x0f;
 
 	link_info->rate = drm_dp_max_link_rate(dpcd);
 	link_info->num_lanes = drm_dp_max_lane_count(dpcd);
@@ -69,7 +82,7 @@ static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
 	if (link_info->rate > dp_panel->max_dp_link_rate)
 		link_info->rate = dp_panel->max_dp_link_rate;
 
-	drm_dbg_dp(panel->drm_dev, "version: %d.%d\n", major, minor);
+	drm_dbg_dp(panel->drm_dev, "version: %d.%d\n", panel->major, panel->minor);
 	drm_dbg_dp(panel->drm_dev, "link_rate=%d\n", link_info->rate);
 	drm_dbg_dp(panel->drm_dev, "lane_count=%d\n", link_info->num_lanes);
 
@@ -280,6 +293,20 @@ void dp_panel_tpg_config(struct dp_panel *dp_panel, bool enable)
 	dp_catalog_panel_tpg_enable(catalog, &panel->dp_panel.dp_mode.drm_mode);
 }
 
+bool dp_panel_vsc_sdp_supported(struct dp_panel *dp_panel)
+{
+	struct dp_panel_private *panel;
+
+	if (!dp_panel) {
+		pr_err("invalid input\n");
+		return false;
+	}
+
+	panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
+
+	return panel->major >= 1 && panel->minor >= 3 && panel->vsc_supported;
+}
+
 void dp_panel_dump_regs(struct dp_panel *dp_panel)
 {
 	struct dp_catalog *catalog;
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.h b/drivers/gpu/drm/msm/dp/dp_panel.h
index 6ec68be9f2366..590eca5ce304b 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.h
+++ b/drivers/gpu/drm/msm/dp/dp_panel.h
@@ -66,6 +66,7 @@ int dp_panel_get_modes(struct dp_panel *dp_panel,
 		struct drm_connector *connector);
 void dp_panel_handle_sink_request(struct dp_panel *dp_panel);
 void dp_panel_tpg_config(struct dp_panel *dp_panel, bool enable);
+bool dp_panel_vsc_sdp_supported(struct dp_panel *dp_panel);
 
 /**
  * is_link_rate_valid() - validates the link rate
-- 
2.39.2