drm/amd/display: Refactor LTTPR mode selection

[WHY]
Previously, LTTPR mode was decided during detection which makes
link training inflexible as mode can't be dynamically changed.

[HOW]
-Remove lttpr_mode from link struct, and move to link training settings
-Defer choosing LTTPR mode until link training

Other DP changes included:
-Only use fixed vs/pe link training sequence for 8b/10b encoding
-Restrict fixed vs aux timeout workaround to Yellow Carp family
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -35,6 +35,8 @@
 #include "dc_link_ddc.h"
 #include "dce/dce_aux.h"
 #include "dmub/inc/dmub_cmd.h"
+#include "link_dpcd.h"
+#include "include/dal_asic_id.h"
 
 #define DC_LOGGER_INIT(logger)
 
@@ -683,6 +685,21 @@ bool dc_link_aux_try_to_configure_timeout(struct ddc_service *ddc,
 	bool result = false;
 	struct ddc *ddc_pin = ddc->ddc_pin;
 
+	if ((ddc->link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+			!ddc->link->dc->debug.disable_fixed_vs_aux_timeout_wa &&
+			ASICREV_IS_YELLOW_CARP(ddc->ctx->asic_id.hw_internal_rev)) {
+		/* Fixed VS workaround for AUX timeout */
+		const uint32_t fixed_vs_address = 0xF004F;
+		const uint8_t fixed_vs_data[4] = {0x1, 0x22, 0x63, 0xc};
+
+		core_link_write_dpcd(ddc->link,
+				fixed_vs_address,
+				fixed_vs_data,
+				sizeof(fixed_vs_data));
+
+		timeout = 3072;
+	}
+
 	/* Do not try to access nonexistent DDC pin. */
 	if (ddc->link->ep_type != DISPLAY_ENDPOINT_PHY)
 		return true;
@@ -691,6 +708,7 @@ bool dc_link_aux_try_to_configure_timeout(struct ddc_service *ddc,
 		ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en]->funcs->configure_timeout(ddc, timeout);
 		result = true;
 	}
+
 	return result;
 }
 

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

@@ -115,12 +115,14 @@ static enum link_training_result dpia_configure_link(
 	DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) configuring\n - LTTPR mode(%d)\n",
 				__func__,
 				link->link_id.enum_id - ENUM_ID_1,
-				link->lttpr_mode);
+				lt_settings->lttpr_mode);
 
 	dp_decide_training_settings(link,
 		link_setting,
 		lt_settings);
 
+	dp_get_lttpr_mode_override(link, &lt_settings->lttpr_mode);
+
 	status = dpcd_configure_channel_coding(link, lt_settings);
 	if (status != DC_OK && link->is_hpd_pending)
 		return LINK_TRAINING_ABORT;
@@ -178,7 +180,7 @@ static uint8_t dpia_build_set_config_data(enum dpia_set_config_type type,
 
 	switch (type) {
 	case DPIA_SET_CFG_SET_LINK:
-		data.set_link.mode = link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT ? 1 : 0;
+		data.set_link.mode = lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT ? 1 : 0;
 		break;
 	case DPIA_SET_CFG_SET_PHY_TEST_MODE:
 		break;
@@ -553,7 +555,7 @@ static enum link_training_result dpia_training_cr_phase(
 {
 	enum link_training_result result = LINK_TRAINING_CR_FAIL_LANE0;
 
-	if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
+	if (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
 		result = dpia_training_cr_non_transparent(link, link_res, lt_settings, hop);
 	else
 		result = dpia_training_cr_transparent(link, link_res, lt_settings);
@@ -830,7 +832,7 @@ static enum link_training_result dpia_training_eq_phase(
 {
 	enum link_training_result result;
 
-	if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
+	if (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
 		result = dpia_training_eq_non_transparent(link, link_res, lt_settings, hop);
 	else
 		result = dpia_training_eq_transparent(link, link_res, lt_settings);
@@ -870,13 +872,14 @@ static enum dc_status dpcd_clear_lt_pattern(struct dc_link *link, uint32_t hop)
  * @param hop The Hop in display path. DPRX = 0.
  */
 static enum link_training_result dpia_training_end(struct dc_link *link,
+		struct link_training_settings *lt_settings,
 		uint32_t hop)
 {
 	enum link_training_result result = LINK_TRAINING_SUCCESS;
 	uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */
 	enum dc_status status;
 
-	if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
+	if (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
 		repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
 
 		if (hop == repeater_cnt) { /* DPTX-to-DPIA */
@@ -916,7 +919,7 @@ static enum link_training_result dpia_training_end(struct dc_link *link,
 				link->link_id.enum_id - ENUM_ID_1,
 				hop,
 				result,
-				link->lttpr_mode);
+				lt_settings->lttpr_mode);
 
 	return result;
 }
@@ -928,7 +931,9 @@ static enum link_training_result dpia_training_end(struct dc_link *link,
  * @param link DPIA link being trained.
  * @param hop The Hop in display path. DPRX = 0.
  */
-static void dpia_training_abort(struct dc_link *link, uint32_t hop)
+static void dpia_training_abort(struct dc_link *link,
+	struct link_training_settings *lt_settings,
+	uint32_t hop)
 {
 	uint8_t data = 0;
 	uint32_t dpcd_tps_offset = DP_TRAINING_PATTERN_SET;
@@ -936,7 +941,7 @@ static void dpia_training_abort(struct dc_link *link, uint32_t hop)
 	DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) aborting\n - LTTPR mode(%d)\n - HPD(%d)\n",
 				__func__,
 				link->link_id.enum_id - ENUM_ID_1,
-				link->lttpr_mode,
+				lt_settings->lttpr_mode,
 				link->is_hpd_pending);
 
 	/* Abandon clean-up if sink unplugged. */
@@ -964,12 +969,16 @@ enum link_training_result dc_link_dpia_perform_link_training(
 	uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */
 	int8_t repeater_id; /* Current hop. */
 
+	struct dc_link_settings link_settings = *link_setting; // non-const copy to pass in
+
+	lt_settings.lttpr_mode = dp_decide_lttpr_mode(link, &link_settings);
+
 	/* Configure link as prescribed in link_setting and set LTTPR mode. */
 	result = dpia_configure_link(link, link_res, link_setting, &lt_settings);
 	if (result != LINK_TRAINING_SUCCESS)
 		return result;
 
-	if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
+	if (lt_settings.lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
 		repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
 
 	/* Train each hop in turn starting with the one closest to DPTX.
@@ -987,7 +996,7 @@ enum link_training_result dc_link_dpia_perform_link_training(
 			break;
 
 		/* Stop training hop. */
-		result = dpia_training_end(link, repeater_id);
+		result = dpia_training_end(link, &lt_settings, repeater_id);
 		if (result != LINK_TRAINING_SUCCESS)
 			break;
 	}
@@ -1001,9 +1010,9 @@ enum link_training_result dc_link_dpia_perform_link_training(
 		msleep(5);
 		result = dp_check_link_loss_status(link, &lt_settings);
 	} else if (result == LINK_TRAINING_ABORT) {
-		dpia_training_abort(link, repeater_id);
+		dpia_training_abort(link, &lt_settings, repeater_id);
 	} else {
-		dpia_training_end(link, repeater_id);
+		dpia_training_end(link, &lt_settings, repeater_id);
 	}
 	return result;
 }

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

@@ -157,7 +157,6 @@ struct dc_link {
 	bool link_state_valid;
 	bool aux_access_disabled;
 	bool sync_lt_in_progress;
-	enum lttpr_mode lttpr_mode;
 	bool is_internal_display;
 
 	/* TODO: Rename. Flag an endpoint as having a programmable mapping to a

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

@@ -194,6 +194,11 @@ enum dc_status dpcd_configure_lttpr_mode(
 
 enum dp_link_encoding dp_get_link_encoding_format(const struct dc_link_settings *link_settings);
 bool dp_retrieve_lttpr_cap(struct dc_link *link);
+bool dp_is_lttpr_present(struct dc_link *link);
+enum lttpr_mode dp_decide_lttpr_mode(struct dc_link *link, struct dc_link_settings *link_setting);
+void dp_get_lttpr_mode_override(struct dc_link *link, enum lttpr_mode *override);
+enum lttpr_mode dp_decide_8b_10b_lttpr_mode(struct dc_link *link);
+enum lttpr_mode dp_decide_128b_132b_lttpr_mode(struct dc_link *link);
 bool dpcd_write_128b_132b_sst_payload_allocation_table(
 		const struct dc_stream_state *stream,
 		struct dc_link *link,

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

@@ -83,6 +83,7 @@ enum link_training_result {
 };
 
 enum lttpr_mode {
+	LTTPR_MODE_UNKNOWN,
 	LTTPR_MODE_NON_LTTPR,
 	LTTPR_MODE_TRANSPARENT,
 	LTTPR_MODE_NON_TRANSPARENT,