drm/amd/display: verify lane status before exiting verify link cap

[why]
DP LL CTS1.4 4.3.2.1 test failure.

[how]
The failure is caused by not handling DP link loss
hpd short pusle during set mode. The change is to read link status
before set mode link training. If link is lost, re-verify link caps.
Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1089,6 +1089,121 @@ static struct dc_link_settings get_max_link_cap(struct dc_link *link)
 	return max_link_cap;
 }
 
+static enum dc_status read_hpd_rx_irq_data(
+	struct dc_link *link,
+	union hpd_irq_data *irq_data)
+{
+	static enum dc_status retval;
+
+	/* The HW reads 16 bytes from 200h on HPD,
+	 * but if we get an AUX_DEFER, the HW cannot retry
+	 * and this causes the CTS tests 4.3.2.1 - 3.2.4 to
+	 * fail, so we now explicitly read 6 bytes which is
+	 * the req from the above mentioned test cases.
+	 *
+	 * For DP 1.4 we need to read those from 2002h range.
+	 */
+	if (link->dpcd_caps.dpcd_rev.raw < DPCD_REV_14)
+		retval = core_link_read_dpcd(
+			link,
+			DP_SINK_COUNT,
+			irq_data->raw,
+			sizeof(union hpd_irq_data));
+	else {
+		/* Read 14 bytes in a single read and then copy only the required fields.
+		 * This is more efficient than doing it in two separate AUX reads. */
+
+		uint8_t tmp[DP_SINK_STATUS_ESI - DP_SINK_COUNT_ESI + 1];
+
+		retval = core_link_read_dpcd(
+			link,
+			DP_SINK_COUNT_ESI,
+			tmp,
+			sizeof(tmp));
+
+		if (retval != DC_OK)
+			return retval;
+
+		irq_data->bytes.sink_cnt.raw = tmp[DP_SINK_COUNT_ESI - DP_SINK_COUNT_ESI];
+		irq_data->bytes.device_service_irq.raw = tmp[DP_DEVICE_SERVICE_IRQ_VECTOR_ESI0 - DP_SINK_COUNT_ESI];
+		irq_data->bytes.lane01_status.raw = tmp[DP_LANE0_1_STATUS_ESI - DP_SINK_COUNT_ESI];
+		irq_data->bytes.lane23_status.raw = tmp[DP_LANE2_3_STATUS_ESI - DP_SINK_COUNT_ESI];
+		irq_data->bytes.lane_status_updated.raw = tmp[DP_LANE_ALIGN_STATUS_UPDATED_ESI - DP_SINK_COUNT_ESI];
+		irq_data->bytes.sink_status.raw = tmp[DP_SINK_STATUS_ESI - DP_SINK_COUNT_ESI];
+	}
+
+	return retval;
+}
+
+static bool hpd_rx_irq_check_link_loss_status(
+	struct dc_link *link,
+	union hpd_irq_data *hpd_irq_dpcd_data)
+{
+	uint8_t irq_reg_rx_power_state = 0;
+	enum dc_status dpcd_result = DC_ERROR_UNEXPECTED;
+	union lane_status lane_status;
+	uint32_t lane;
+	bool sink_status_changed;
+	bool return_code;
+
+	sink_status_changed = false;
+	return_code = false;
+
+	if (link->cur_link_settings.lane_count == 0)
+		return return_code;
+
+	/*1. Check that Link Status changed, before re-training.*/
+
+	/*parse lane status*/
+	for (lane = 0; lane < link->cur_link_settings.lane_count; lane++) {
+		/* check status of lanes 0,1
+		 * changed DpcdAddress_Lane01Status (0x202)
+		 */
+		lane_status.raw = get_nibble_at_index(
+			&hpd_irq_dpcd_data->bytes.lane01_status.raw,
+			lane);
+
+		if (!lane_status.bits.CHANNEL_EQ_DONE_0 ||
+			!lane_status.bits.CR_DONE_0 ||
+			!lane_status.bits.SYMBOL_LOCKED_0) {
+			/* if one of the channel equalization, clock
+			 * recovery or symbol lock is dropped
+			 * consider it as (link has been
+			 * dropped) dp sink status has changed
+			 */
+			sink_status_changed = true;
+			break;
+		}
+	}
+
+	/* Check interlane align.*/
+	if (sink_status_changed ||
+		!hpd_irq_dpcd_data->bytes.lane_status_updated.bits.INTERLANE_ALIGN_DONE) {
+
+		DC_LOG_HW_HPD_IRQ("%s: Link Status changed.\n", __func__);
+
+		return_code = true;
+
+		/*2. Check that we can handle interrupt: Not in FS DOS,
+		 *  Not in "Display Timeout" state, Link is trained.
+		 */
+		dpcd_result = core_link_read_dpcd(link,
+			DP_SET_POWER,
+			&irq_reg_rx_power_state,
+			sizeof(irq_reg_rx_power_state));
+
+		if (dpcd_result != DC_OK) {
+			DC_LOG_HW_HPD_IRQ("%s: DPCD read failed to obtain power state.\n",
+				__func__);
+		} else {
+			if (irq_reg_rx_power_state != DP_SET_POWER_D0)
+				return_code = false;
+		}
+	}
+
+	return return_code;
+}
+
 bool dp_verify_link_cap(
 	struct dc_link *link,
 	struct dc_link_settings *known_limit_link_setting,
@@ -1104,12 +1219,14 @@ bool dp_verify_link_cap(
 	struct clock_source *dp_cs;
 	enum clock_source_id dp_cs_id = CLOCK_SOURCE_ID_EXTERNAL;
 	enum link_training_result status;
+	union hpd_irq_data irq_data;
 
 	if (link->dc->debug.skip_detection_link_training) {
 		link->verified_link_cap = *known_limit_link_setting;
 		return true;
 	}
 
+	memset(&irq_data, 0, sizeof(irq_data));
 	success = false;
 	skip_link_training = false;
 
@@ -1168,9 +1285,15 @@ bool dp_verify_link_cap(
 				(*fail_count)++;
 		}
 
-		if (success)
+		if (success) {
 			link->verified_link_cap = *cur;
-
+			udelay(1000);
+			if (read_hpd_rx_irq_data(link, &irq_data) == DC_OK)
+				if (hpd_rx_irq_check_link_loss_status(
+						link,
+						&irq_data))
+					(*fail_count)++;
+		}
 		/* always disable the link before trying another
 		 * setting or before returning we'll enable it later
 		 * based on the actual mode we're driving
@@ -1572,122 +1695,6 @@ void decide_link_settings(struct dc_stream_state *stream,
 }
 
 /*************************Short Pulse IRQ***************************/
-
-static bool hpd_rx_irq_check_link_loss_status(
-	struct dc_link *link,
-	union hpd_irq_data *hpd_irq_dpcd_data)
-{
-	uint8_t irq_reg_rx_power_state = 0;
-	enum dc_status dpcd_result = DC_ERROR_UNEXPECTED;
-	union lane_status lane_status;
-	uint32_t lane;
-	bool sink_status_changed;
-	bool return_code;
-
-	sink_status_changed = false;
-	return_code = false;
-
-	if (link->cur_link_settings.lane_count == 0)
-		return return_code;
-
-	/*1. Check that Link Status changed, before re-training.*/
-
-	/*parse lane status*/
-	for (lane = 0; lane < link->cur_link_settings.lane_count; lane++) {
-		/* check status of lanes 0,1
-		 * changed DpcdAddress_Lane01Status (0x202)
-		 */
-		lane_status.raw = get_nibble_at_index(
-			&hpd_irq_dpcd_data->bytes.lane01_status.raw,
-			lane);
-
-		if (!lane_status.bits.CHANNEL_EQ_DONE_0 ||
-			!lane_status.bits.CR_DONE_0 ||
-			!lane_status.bits.SYMBOL_LOCKED_0) {
-			/* if one of the channel equalization, clock
-			 * recovery or symbol lock is dropped
-			 * consider it as (link has been
-			 * dropped) dp sink status has changed
-			 */
-			sink_status_changed = true;
-			break;
-		}
-	}
-
-	/* Check interlane align.*/
-	if (sink_status_changed ||
-		!hpd_irq_dpcd_data->bytes.lane_status_updated.bits.INTERLANE_ALIGN_DONE) {
-
-		DC_LOG_HW_HPD_IRQ("%s: Link Status changed.\n", __func__);
-
-		return_code = true;
-
-		/*2. Check that we can handle interrupt: Not in FS DOS,
-		 *  Not in "Display Timeout" state, Link is trained.
-		 */
-		dpcd_result = core_link_read_dpcd(link,
-			DP_SET_POWER,
-			&irq_reg_rx_power_state,
-			sizeof(irq_reg_rx_power_state));
-
-		if (dpcd_result != DC_OK) {
-			DC_LOG_HW_HPD_IRQ("%s: DPCD read failed to obtain power state.\n",
-				__func__);
-		} else {
-			if (irq_reg_rx_power_state != DP_SET_POWER_D0)
-				return_code = false;
-		}
-	}
-
-	return return_code;
-}
-
-static enum dc_status read_hpd_rx_irq_data(
-	struct dc_link *link,
-	union hpd_irq_data *irq_data)
-{
-	static enum dc_status retval;
-
-	/* The HW reads 16 bytes from 200h on HPD,
-	 * but if we get an AUX_DEFER, the HW cannot retry
-	 * and this causes the CTS tests 4.3.2.1 - 3.2.4 to
-	 * fail, so we now explicitly read 6 bytes which is
-	 * the req from the above mentioned test cases.
-	 *
-	 * For DP 1.4 we need to read those from 2002h range.
-	 */
-	if (link->dpcd_caps.dpcd_rev.raw < DPCD_REV_14)
-		retval = core_link_read_dpcd(
-			link,
-			DP_SINK_COUNT,
-			irq_data->raw,
-			sizeof(union hpd_irq_data));
-	else {
-		/* Read 14 bytes in a single read and then copy only the required fields.
-		 * This is more efficient than doing it in two separate AUX reads. */
-
-		uint8_t tmp[DP_SINK_STATUS_ESI - DP_SINK_COUNT_ESI + 1];
-
-		retval = core_link_read_dpcd(
-			link,
-			DP_SINK_COUNT_ESI,
-			tmp,
-			sizeof(tmp));
-
-		if (retval != DC_OK)
-			return retval;
-
-		irq_data->bytes.sink_cnt.raw = tmp[DP_SINK_COUNT_ESI - DP_SINK_COUNT_ESI];
-		irq_data->bytes.device_service_irq.raw = tmp[DP_DEVICE_SERVICE_IRQ_VECTOR_ESI0 - DP_SINK_COUNT_ESI];
-		irq_data->bytes.lane01_status.raw = tmp[DP_LANE0_1_STATUS_ESI - DP_SINK_COUNT_ESI];
-		irq_data->bytes.lane23_status.raw = tmp[DP_LANE2_3_STATUS_ESI - DP_SINK_COUNT_ESI];
-		irq_data->bytes.lane_status_updated.raw = tmp[DP_LANE_ALIGN_STATUS_UPDATED_ESI - DP_SINK_COUNT_ESI];
-		irq_data->bytes.sink_status.raw = tmp[DP_SINK_STATUS_ESI - DP_SINK_COUNT_ESI];
-	}
-
-	return retval;
-}
-
 static bool allow_hpd_rx_irq(const struct dc_link *link)
 {
 	/*

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

@@ -96,6 +96,7 @@ void dp_enable_link_phy(
 						link_settings,
 						clock_source);
 	}
+	link->cur_link_settings = *link_settings;
 
 	dp_receiver_power_ctrl(link, true);
 }
@@ -307,6 +308,7 @@ void dp_retrain_link_dp_test(struct dc_link *link,
 						link->link_enc,
 						link_setting,
 						pipes[i].clock_source->id);
+			link->cur_link_settings = *link_setting;
 
 			dp_receiver_power_ctrl(link, true);
 
@@ -316,7 +318,6 @@ void dp_retrain_link_dp_test(struct dc_link *link,
 					skip_video_pattern,
 					LINK_TRAINING_ATTEMPTS);
 
-			link->cur_link_settings = *link_setting;
 
 			link->dc->hwss.enable_stream(&pipes[i]);