drm/amd/display: Update setting of DP training parameters.

[Why]
Some links are dynamically assigned link encoders on stream enablement.

[How]
Update DisplayPort training parameter determination stage that assumes
link encoder statically assigned to link.

Signed-off-by: Jimmy Kizito <[e-mail]>
Reviewed-by: Jun Lei <[e-mail]>
Acked-by: Stylon Wang <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 #include "dce/dmub_psr.h"
 #include "dmub/dmub_srv.h"
 #include "inc/hw/panel_cntl.h"
+#include "inc/link_enc_cfg.h"
 
 #define DC_LOGGER_INIT(logger)
 
···
 
 bool dc_link_is_fec_supported(const struct dc_link *link)
 {
+	struct link_encoder *link_enc = NULL;
+
+	/* Links supporting dynamically assigned link encoder will be assigned next
+	 * available encoder if one not already assigned.
+	 */
+	if (link->is_dig_mapping_flexible &&
+			link->dc->res_pool->funcs->link_encs_assign) {
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+		if (link_enc == NULL)
+			link_enc = link_enc_cfg_get_next_avail_link_enc(link->dc, link->dc->current_state);
+	} else
+		link_enc = link->link_enc;
+	ASSERT(link_enc);
+
 	return (dc_is_dp_signal(link->connector_signal) &&
-			link->link_enc->features.fec_supported &&
+			link_enc->features.fec_supported &&
 			link->dpcd_caps.fec_cap.bits.FEC_CAPABLE &&
 			!IS_FPGA_MAXIMUS_DC(link->ctx->dce_environment));
 }

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

···
 	bool result = false;
 	struct ddc *ddc_pin = ddc->ddc_pin;
 
+	/* Do not try to access nonexistent DDC pin. */
+	if (ddc->link->ep_type != DISPLAY_ENDPOINT_PHY)
+		return true;
+
 	if (ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en]->funcs->configure_timeout) {
 		ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en]->funcs->configure_timeout(ddc, timeout);
 		result = true;

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

···
 #include "dpcd_defs.h"
 #include "dc_dmub_srv.h"
 #include "dce/dmub_hw_lock_mgr.h"
+#include "inc/link_enc_cfg.h"
 
 /*Travis*/
 static const uint8_t DP_VGA_LVDS_CONVERTER_ID_2[] = "sivarT";
···
 static enum dc_dp_training_pattern decide_eq_training_pattern(struct dc_link *link,
 		const struct dc_link_settings *link_settings)
 {
+	struct link_encoder *link_enc;
 	enum dc_dp_training_pattern highest_tp = DP_TRAINING_PATTERN_SEQUENCE_2;
-	struct encoder_feature_support *features = &link->link_enc->features;
+	struct encoder_feature_support *features;
 	struct dpcd_caps *dpcd_caps = &link->dpcd_caps;
+
+	/* Access link encoder capability based on whether it is statically
+	 * or dynamically assigned to a link.
+	 */
+	if (link->is_dig_mapping_flexible &&
+			link->dc->res_pool->funcs->link_encs_assign)
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+	else
+		link_enc = link->link_enc;
+	ASSERT(link_enc);
+	features = &link_enc->features;
 
 	if (features->flags.bits.IS_TPS3_CAPABLE)
 		highest_tp = DP_TRAINING_PATTERN_SEQUENCE_3;
···
 		}
 
 		repeater_cnt = convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+
 		for (repeater_id = repeater_cnt; repeater_id > 0; repeater_id--) {
 			aux_interval_address = DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1 +
 						((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (repeater_id - 1));
···
 				lttpr_dpcd_data[DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT -
 								DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];
 
+		/* Attempt to train in LTTPR transparent mode if repeater count exceeds 8. */
 		is_lttpr_present = (link->dpcd_caps.lttpr_caps.phy_repeater_cnt > 0 &&
+				link->dpcd_caps.lttpr_caps.phy_repeater_cnt < 0xff &&
 				link->dpcd_caps.lttpr_caps.max_lane_count > 0 &&
 				link->dpcd_caps.lttpr_caps.max_lane_count <= 4 &&
 				link->dpcd_caps.lttpr_caps.revision.raw >= 0x14);

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

···
 
 /* Return first available DIG link encoder. */
 static enum engine_id find_first_avail_link_enc(
-		struct dc_context *ctx,
-		struct dc_state *state)
+		const struct dc_context *ctx,
+		const struct dc_state *state)
 {
 	enum engine_id eng_id = ENGINE_ID_UNKNOWN;
 	int i;
···
 
 struct link_encoder *link_enc_cfg_get_link_enc_used_by_link(
 		struct dc_state *state,
-		struct dc_link *link)
+		const struct dc_link *link)
 {
 	struct link_encoder *link_enc = NULL;
 	struct display_endpoint_id ep_id;
···
 
 	if (stream_idx != -1)
 		link_enc = state->streams[stream_idx]->link_enc;
-	else
-		dm_output_to_console("%s: No link encoder used by link(%d).\n", __func__, link->link_index);
+
+	return link_enc;
+}
+
+struct link_encoder *link_enc_cfg_get_next_avail_link_enc(
+	const struct dc *dc,
+	const struct dc_state *state)
+{
+	struct link_encoder *link_enc = NULL;
+	enum engine_id eng_id = ENGINE_ID_UNKNOWN;
+
+	eng_id = find_first_avail_link_enc(dc->ctx, state);
+	if (eng_id != ENGINE_ID_UNKNOWN)
+		link_enc = dc->res_pool->link_encoders[eng_id - ENGINE_ID_DIGA];
 
 	return link_enc;
 }

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

···
 /* Return DIG link encoder used by link. NULL if unused. */
 struct link_encoder *link_enc_cfg_get_link_enc_used_by_link(
 		struct dc_state *state,
-		struct dc_link *link);
+		const struct dc_link *link);
+
+/* Return next available DIG link encoder. NULL if none available. */
+struct link_encoder *link_enc_cfg_get_next_avail_link_enc(
+	const struct dc *dc,
+	const struct dc_state *state);
 
 #endif /* DC_INC_LINK_ENC_CFG_H_ */