drm/amd/display: Serialize is_dp_sink_present

Access to GPIO needs to be serialized. Aux transactions are already
serialized in DRM but we also need to serialize access to the GPIO pin
for purposes of DP dongle detection.

Call is_dp_sink_present through DM so we can lock correctly. This
follows the same pattern used for DPCD transactions.
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c

@@ -454,6 +454,22 @@ bool dm_helpers_submit_i2c(
 	return result;
 }
 
+bool dm_helpers_is_dp_sink_present(struct dc_link *link)
+{
+	bool dp_sink_present;
+	struct amdgpu_dm_connector *aconnector = link->priv;
+
+	if (!aconnector) {
+		BUG_ON("Failed to found connector for link!");
+		return true;
+	}
+
+	mutex_lock(&aconnector->dm_dp_aux.aux.hw_mutex);
+	dp_sink_present = dc_link_is_dp_sink_present(link);
+	mutex_unlock(&aconnector->dm_dp_aux.aux.hw_mutex);
+	return dp_sink_present;
+}
+
 enum dc_edid_status dm_helpers_read_local_edid(
 		struct dc_context *ctx,
 		struct dc_link *link,

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -313,7 +313,7 @@ static enum signal_type get_basic_signal_type(
  * @brief
  * Check whether there is a dongle on DP connector
  */
-static bool is_dp_sink_present(struct dc_link *link)
+bool dc_link_is_dp_sink_present(struct dc_link *link)
 {
 	enum gpio_result gpio_result;
 	uint32_t clock_pin = 0;
@@ -406,7 +406,7 @@ static enum signal_type link_detect_sink(
 			 * we assume signal is DVI; it could be corrected
 			 * to HDMI after dongle detection
 			 */
-			if (!is_dp_sink_present(link))
+			if (!dm_helpers_is_dp_sink_present(link))
 				result = SIGNAL_TYPE_DVI_SINGLE_LINK;
 		}
 	}

drivers/gpu/drm/amd/display/dc/dc_link.h

@@ -210,6 +210,8 @@ bool dc_link_dp_set_test_pattern(
 
 void dc_link_enable_hpd_filter(struct dc_link *link, bool enable);
 
+bool dc_link_is_dp_sink_present(struct dc_link *link);
+
 /*
  * DPCD access interfaces
  */

drivers/gpu/drm/amd/display/dc/dm_helpers.h

@@ -103,6 +103,9 @@ bool dm_helpers_submit_i2c(
 		const struct dc_link *link,
 		struct i2c_command *cmd);
 
+bool dm_helpers_is_dp_sink_present(
+		struct dc_link *link);
+
 enum dc_edid_status dm_helpers_read_local_edid(
 		struct dc_context *ctx,
 		struct dc_link *link,