void mainboard_train_link(struct intel_dp *intel_dp)
{
u8 read_val;
u8 link_status[DP_LINK_STATUS_SIZE];
gtt_write(DP_TP_CTL(intel_dp->port),DP_TP_CTL_ENABLE | DP_TP_CTL_ENHANCED_FRAME_ENABLE);
gtt_write(DP_A, DP_PORT_EN | DP_LINK_TRAIN_PAT_1 | DP_LINK_TRAIN_PAT_1_CPT | DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0 | DP_PORT_WIDTH_1 | DP_PLL_FREQ_270MHZ | DP_SYNC_VS_HIGH |0x80000011);
intel_dp_get_training_pattern(intel_dp, &read_val);
intel_dp_set_training_pattern(intel_dp, DP_TRAINING_PATTERN_1 | DP_LINK_QUAL_PATTERN_DISABLE | DP_SYMBOL_ERROR_COUNT_BOTH);
intel_dp_get_lane_count(intel_dp, &read_val);
intel_dp_set_training_lane0(intel_dp, DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0);
intel_dp_get_link_status(intel_dp, link_status);
gtt_write(DP_TP_CTL(intel_dp->port),DP_TP_CTL_ENABLE | DP_TP_CTL_ENHANCED_FRAME_ENABLE | DP_TP_CTL_LINK_TRAIN_PAT2);
intel_dp_get_training_pattern(intel_dp, &read_val);
intel_dp_set_training_pattern(intel_dp, DP_TRAINING_PATTERN_2 | DP_LINK_QUAL_PATTERN_DISABLE | DP_SYMBOL_ERROR_COUNT_BOTH);
intel_dp_get_link_status(intel_dp, link_status);
intel_dp_get_lane_align_status(intel_dp, &read_val);
intel_dp_get_training_pattern(intel_dp, &read_val);
intel_dp_set_training_pattern(intel_dp, DP_TRAINING_PATTERN_DISABLE | DP_LINK_QUAL_PATTERN_DISABLE | DP_SYMBOL_ERROR_COUNT_BOTH);
}
static void
intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
{
bool channel_eq = false;
int tries, cr_tries;
u32 training_pattern;
training_pattern = intel_dp_training_pattern(intel_dp);
/* channel equalization */
if (!intel_dp_set_link_train(intel_dp,
training_pattern |
DP_LINK_SCRAMBLING_DISABLE)) {
DRM_ERROR("failed to start channel equalization\n");
return;
}
tries = 0;
cr_tries = 0;
channel_eq = false;
for (;;) {
uint8_t link_status[DP_LINK_STATUS_SIZE];
if (cr_tries > 5) {
DRM_ERROR("failed to train DP, aborting\n");
intel_dp_dump_link_status(link_status);
break;
}
drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
if (!intel_dp_get_link_status(intel_dp, link_status)) {
DRM_ERROR("failed to get link status\n");
break;
}
/* Make sure clock is still ok */
if (!drm_dp_clock_recovery_ok(link_status,
intel_dp->lane_count)) {
intel_dp_link_training_clock_recovery(intel_dp);
intel_dp_set_link_train(intel_dp,
training_pattern |
DP_LINK_SCRAMBLING_DISABLE);
cr_tries++;
continue;
}
if (drm_dp_channel_eq_ok(link_status,
intel_dp->lane_count)) {
channel_eq = true;
break;
}
/* Try 5 times, then try clock recovery if that fails */
if (tries > 5) {
intel_dp_link_training_clock_recovery(intel_dp);
intel_dp_set_link_train(intel_dp,
training_pattern |
DP_LINK_SCRAMBLING_DISABLE);
tries = 0;
cr_tries++;
continue;
}
/* Update training set as requested by target */
intel_get_adjust_train(intel_dp, link_status);
if (!intel_dp_update_link_train(intel_dp)) {
DRM_ERROR("failed to update link training\n");
break;
}
++tries;
}
intel_dp_set_idle_link_train(intel_dp);
if (channel_eq)
DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n");
}
/* Enable corresponding port and start training pattern 1 */
static void
intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
{
int i;
uint8_t voltage;
int voltage_tries, loop_tries;
uint8_t link_config[2];
uint8_t link_bw, rate_select;
if (intel_dp->prepare_link_retrain)
intel_dp->prepare_link_retrain(intel_dp);
intel_dp_compute_rate(intel_dp, intel_dp->link_rate,
&link_bw, &rate_select);
/* Write the link configuration data */
link_config[0] = link_bw;
link_config[1] = intel_dp->lane_count;
if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2);
if (intel_dp->num_sink_rates)
drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET,
&rate_select, 1);
link_config[0] = 0;
link_config[1] = DP_SET_ANSI_8B10B;
drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2);
intel_dp->DP |= DP_PORT_EN;
/* clock recovery */
if (!intel_dp_reset_link_train(intel_dp,
DP_TRAINING_PATTERN_1 |
DP_LINK_SCRAMBLING_DISABLE)) {
DRM_ERROR("failed to enable link training\n");
return;
}
voltage = 0xff;
voltage_tries = 0;
loop_tries = 0;
for (;;) {
uint8_t link_status[DP_LINK_STATUS_SIZE];
drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
if (!intel_dp_get_link_status(intel_dp, link_status)) {
DRM_ERROR("failed to get link status\n");
break;
}
if (drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) {
DRM_DEBUG_KMS("clock recovery OK\n");
break;
}
/* Check to see if we've tried the max voltage */
for (i = 0; i < intel_dp->lane_count; i++)
if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
break;
if (i == intel_dp->lane_count) {
++loop_tries;
if (loop_tries == 5) {
DRM_ERROR("too many full retries, give up\n");
intel_dp_dump_link_status(link_status);
break;
}
intel_dp_reset_link_train(intel_dp,
DP_TRAINING_PATTERN_1 |
DP_LINK_SCRAMBLING_DISABLE);
voltage_tries = 0;
continue;
}
/* Check to see if we've tried the same voltage 5 times */
if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
++voltage_tries;
if (voltage_tries == 5) {
DRM_ERROR("too many voltage retries, give up\n");
break;
}
} else
voltage_tries = 0;
voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
/* Update training set as requested by target */
intel_get_adjust_train(intel_dp, link_status);
if (!intel_dp_update_link_train(intel_dp)) {
DRM_ERROR("failed to update link training\n");
break;
}
}
}
