drm/amd/display: Add ability to set preferred link training parameters.

[WHY]
To add support for OS requirement to set preferred link training
parameters.

[HOW]
Create new structure of dp link training overrides. During link training
processes, these values should be used instead of the default training
parameters.
Signed-off-by: David Galiffi <David.Galiffi@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@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.c

@@ -1189,6 +1189,9 @@ static bool construct(
 	link->ctx = dc_ctx;
 	link->link_index = init_params->link_index;
 
+	memset(&link->preferred_training_settings, 0, sizeof(struct dc_link_training_overrides));
+	memset(&link->preferred_link_setting, 0, sizeof(struct dc_link_settings));
+
 	link->link_id = bios->funcs->get_connector_id(bios, init_params->connector_index);
 
 	if (link->link_id.type != OBJECT_TYPE_CONNECTOR) {
@@ -1467,6 +1470,9 @@ static enum dc_status enable_link_dp(
 	struct dc_link *link = stream->link;
 	struct dc_link_settings link_settings = {0};
 	enum dp_panel_mode panel_mode;
+#ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
+	bool fec_enable;
+#endif
 
 	/* get link settings for video mode timing */
 	decide_link_settings(stream, &link_settings);
@@ -1511,10 +1517,20 @@ static enum dc_status enable_link_dp(
 			skip_video_pattern = false;
 
 #ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
-	dp_set_fec_ready(link, true);
+	if (link->preferred_training_settings.fec_enable != NULL)
+		fec_enable = *link->preferred_training_settings.fec_enable;
+	else
+		fec_enable = true;
+
+	dp_set_fec_ready(link, fec_enable);
 #endif
 
-	if (perform_link_training_with_retries(
+	if (link->aux_access_disabled) {
+		dc_link_dp_perform_link_training_skip_aux(link, &link_settings);
+
+		link->cur_link_settings = link_settings;
+		status = DC_OK;
+	} else if (perform_link_training_with_retries(
 			link,
 			&link_settings,
 			skip_video_pattern,
@@ -1526,7 +1542,7 @@ static enum dc_status enable_link_dp(
 		status = DC_FAIL_DP_LINK_TRAINING;
 
 #ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
-	dp_set_fec_enable(link, true);
+	dp_set_fec_enable(link, fec_enable);
 #endif
 	return status;
 }
@@ -3014,6 +3030,29 @@ void dc_link_set_preferred_link_settings(struct dc *dc,
 		dp_retrain_link_dp_test(link, &store_settings, false);
 }
 
+void dc_link_set_preferred_training_settings(struct dc *dc,
+						 struct dc_link_settings *link_setting,
+						 struct dc_link_training_overrides *lt_overrides,
+						 struct dc_link *link,
+						 bool skip_immediate_retrain)
+{
+	if (lt_overrides != NULL)
+		link->preferred_training_settings = *lt_overrides;
+	else
+		memset(&link->preferred_training_settings, 0, sizeof(link->preferred_training_settings));
+
+	if (link_setting != NULL) {
+		link->preferred_link_setting = *link_setting;
+	} else {
+		link->preferred_link_setting.lane_count = LANE_COUNT_UNKNOWN;
+		link->preferred_link_setting.link_rate = LINK_RATE_UNKNOWN;
+	}
+
+	/* Retrain now, or wait until next stream update to apply */
+	if (skip_immediate_retrain == false)
+		dc_link_set_preferred_link_settings(dc, &link->preferred_link_setting, link);
+}
+
 void dc_link_enable_hpd(const struct dc_link *link)
 {
 	dc_link_dp_enable_hpd(link);
@@ -3024,7 +3063,6 @@ void dc_link_disable_hpd(const struct dc_link *link)
 	dc_link_dp_disable_hpd(link);
 }
 
-
 void dc_link_set_test_pattern(struct dc_link *link,
 			      enum dp_test_pattern test_pattern,
 			      const struct link_training_settings *p_link_settings,

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

@@ -25,10 +25,11 @@ enum dc_status core_link_read_dpcd(
 	uint8_t *data,
 	uint32_t size)
 {
-	if (!dm_helpers_dp_read_dpcd(link->ctx,
-			link,
-			address, data, size))
-			return DC_ERROR_UNEXPECTED;
+	if (!link->aux_access_disabled &&
+			!dm_helpers_dp_read_dpcd(link->ctx,
+			link, address, data, size)) {
+		return DC_ERROR_UNEXPECTED;
+	}
 
 	return DC_OK;
 }
@@ -39,10 +40,11 @@ enum dc_status core_link_write_dpcd(
 	const uint8_t *data,
 	uint32_t size)
 {
-	if (!dm_helpers_dp_write_dpcd(link->ctx,
-			link,
-			address, data, size))
-				return DC_ERROR_UNEXPECTED;
+	if (!link->aux_access_disabled &&
+			!dm_helpers_dp_write_dpcd(link->ctx,
+			link, address, data, size)) {
+		return DC_ERROR_UNEXPECTED;
+	}
 
 	return DC_OK;
 }
@@ -203,21 +205,21 @@ void dp_disable_link_phy_mst(struct dc_link *link, enum signal_type signal)
 
 bool dp_set_hw_training_pattern(
 	struct dc_link *link,
-	enum hw_dp_training_pattern pattern)
+	enum dc_dp_training_pattern pattern)
 {
 	enum dp_test_pattern test_pattern = DP_TEST_PATTERN_UNSUPPORTED;
 
 	switch (pattern) {
-	case HW_DP_TRAINING_PATTERN_1:
+	case DP_TRAINING_PATTERN_SEQUENCE_1:
 		test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN1;
 		break;
-	case HW_DP_TRAINING_PATTERN_2:
+	case DP_TRAINING_PATTERN_SEQUENCE_2:
 		test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN2;
 		break;
-	case HW_DP_TRAINING_PATTERN_3:
+	case DP_TRAINING_PATTERN_SEQUENCE_3:
 		test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN3;
 		break;
-	case HW_DP_TRAINING_PATTERN_4:
+	case DP_TRAINING_PATTERN_SEQUENCE_4:
 		test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN4;
 		break;
 	default:

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

@@ -90,6 +90,13 @@ enum dc_post_cursor2 {
 	POST_CURSOR2_MAX_LEVEL = POST_CURSOR2_LEVEL3,
 };
 
+enum dc_dp_training_pattern {
+	DP_TRAINING_PATTERN_SEQUENCE_1 = 0,
+	DP_TRAINING_PATTERN_SEQUENCE_2,
+	DP_TRAINING_PATTERN_SEQUENCE_3,
+	DP_TRAINING_PATTERN_SEQUENCE_4,
+};
+
 struct dc_link_settings {
 	enum dc_lane_count lane_count;
 	enum dc_link_rate link_rate;
@@ -109,6 +116,20 @@ struct dc_link_training_settings {
 	struct dc_lane_settings lane_settings[LANE_COUNT_DP_MAX];
 };
 
+struct dc_link_training_overrides {
+	enum dc_voltage_swing *voltage_swing;
+	enum dc_pre_emphasis *pre_emphasis;
+	enum dc_post_cursor2 *post_cursor2;
+
+	uint16_t *cr_pattern_time;
+	uint16_t *eq_pattern_time;
+	enum dc_dp_training_pattern *pattern_for_eq;
+
+	enum dc_link_spread *downspread;
+	bool *alternate_scrambler_reset;
+	bool *enhanced_framing;
+	bool *fec_enable;
+};
 
 union dpcd_rev {
 	struct {

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

@@ -83,6 +83,7 @@ struct dc_link {
 	bool is_hpd_filter_disabled;
 	bool dp_ss_off;
 	bool link_state_valid;
+	bool aux_access_disabled;
 
 	/* caps is the same as reported_link_cap. link_traing use
 	 * reported_link_cap. Will clean up.  TODO
@@ -92,6 +93,7 @@ struct dc_link {
 	struct dc_link_settings cur_link_settings;
 	struct dc_lane_settings cur_lane_setting;
 	struct dc_link_settings preferred_link_setting;
+	struct dc_link_training_overrides preferred_training_settings;
 
 	uint8_t ddc_hw_inst;
 
@@ -217,6 +219,10 @@ void dc_link_dp_set_drive_settings(
 	struct dc_link *link,
 	struct link_training_settings *lt_settings);
 
+bool dc_link_dp_perform_link_training_skip_aux(
+	struct dc_link *link,
+	const struct dc_link_settings *link_setting);
+
 enum link_training_result dc_link_dp_perform_link_training(
 	struct dc_link *link,
 	const struct dc_link_settings *link_setting,
@@ -251,6 +257,11 @@ void dc_link_perform_link_training(struct dc *dc,
 void dc_link_set_preferred_link_settings(struct dc *dc,
 					 struct dc_link_settings *link_setting,
 					 struct dc_link *link);
+void dc_link_set_preferred_training_settings(struct dc *dc,
+					struct dc_link_settings *link_setting,
+					struct dc_link_training_overrides *lt_overrides,
+					struct dc_link *link,
+					bool skip_immediate_retrain);
 void dc_link_enable_hpd(const struct dc_link *link);
 void dc_link_disable_hpd(const struct dc_link *link);
 void dc_link_set_test_pattern(struct dc_link *link,

drivers/gpu/drm/amd/display/dc/inc/link_hwss.h

@@ -60,7 +60,7 @@ void dp_disable_link_phy_mst(struct dc_link *link, enum signal_type signal);
 
 bool dp_set_hw_training_pattern(
 	struct dc_link *link,
-	enum hw_dp_training_pattern pattern);
+	enum dc_dp_training_pattern pattern);
 
 void dp_set_hw_lane_settings(
 	struct dc_link *link,

drivers/gpu/drm/amd/display/include/link_service_types.h

@@ -71,14 +71,17 @@ enum link_training_result {
 struct link_training_settings {
 	struct dc_link_settings link_settings;
 	struct dc_lane_settings lane_settings[LANE_COUNT_DP_MAX];
-	bool allow_invalid_msa_timing_param;
-};
 
-enum hw_dp_training_pattern {
-	HW_DP_TRAINING_PATTERN_1 = 0,
-	HW_DP_TRAINING_PATTERN_2,
-	HW_DP_TRAINING_PATTERN_3,
-	HW_DP_TRAINING_PATTERN_4
+	enum dc_voltage_swing *voltage_swing;
+	enum dc_pre_emphasis *pre_emphasis;
+	enum dc_post_cursor2 *post_cursor2;
+
+	uint16_t cr_pattern_time;
+	uint16_t eq_pattern_time;
+	enum dc_dp_training_pattern pattern_for_eq;
+
+	bool enhanced_framing;
+	bool allow_invalid_msa_timing_param;
 };
 
 /*TODO: Move this enum test harness*/