bool radeon_dp_needs_link_train(struct radeon_connector *radeon_connector)
{
u8 link_status[DP_LINK_STATUS_SIZE];
struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
if (!radeon_dp_get_link_status(radeon_connector, link_status))
return false;
if (drm_dp_channel_eq_ok(link_status, dig->dp_lane_count))
return false;
return true;
}
static int radeon_dp_link_train_ce(struct radeon_dp_link_train_info *dp_info)
{
bool channel_eq;
if (dp_info->tp3_supported)
radeon_dp_set_tp(dp_info, DP_TRAINING_PATTERN_3);
else
radeon_dp_set_tp(dp_info, DP_TRAINING_PATTERN_2);
/* channel equalization loop */
dp_info->tries = 0;
channel_eq = false;
while (1) {
if (dp_info->rd_interval == 0)
udelay(400);
else
mdelay(dp_info->rd_interval * 4);
if (!radeon_dp_get_link_status(dp_info->radeon_connector, dp_info->link_status)) {
DRM_ERROR("displayport link status failed\n");
break;
}
if (dp_channel_eq_ok(dp_info->link_status, dp_info->dp_lane_count)) {
channel_eq = true;
break;
}
/* Try 5 times */
if (dp_info->tries > 5) {
DRM_ERROR("channel eq failed: 5 tries\n");
break;
}
/* Compute new train_set as requested by sink */
dp_get_adjust_train(dp_info->link_status, dp_info->dp_lane_count, dp_info->train_set);
radeon_dp_update_vs_emph(dp_info);
dp_info->tries++;
}
if (!channel_eq) {
DRM_ERROR("channel eq failed\n");
return -1;
} else {
DRM_DEBUG_KMS("channel eq at voltage %d pre-emphasis %d\n",
dp_info->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK,
(dp_info->train_set[0] & DP_TRAIN_PRE_EMPHASIS_MASK)
>> DP_TRAIN_PRE_EMPHASIS_SHIFT);
return 0;
}
}
static int radeon_dp_link_train_cr(struct radeon_dp_link_train_info *dp_info)
{
bool clock_recovery;
u8 voltage;
int i;
radeon_dp_set_tp(dp_info, DP_TRAINING_PATTERN_1);
memset(dp_info->train_set, 0, 4);
radeon_dp_update_vs_emph(dp_info);
DRM_UDELAY(400);
/* clock recovery loop */
clock_recovery = false;
dp_info->tries = 0;
voltage = 0xff;
while (1) {
drm_dp_link_train_clock_recovery_delay(dp_info->dpcd);
if (!radeon_dp_get_link_status(dp_info->radeon_connector, dp_info->link_status)) {
DRM_ERROR("displayport link status failed\n");
break;
}
if (drm_dp_clock_recovery_ok(dp_info->link_status, dp_info->dp_lane_count)) {
clock_recovery = true;
break;
}
for (i = 0; i < dp_info->dp_lane_count; i++) {
if ((dp_info->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
break;
}
if (i == dp_info->dp_lane_count) {
DRM_ERROR("clock recovery reached max voltage\n");
break;
}
if ((dp_info->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
++dp_info->tries;
if (dp_info->tries == 5) {
DRM_ERROR("clock recovery tried 5 times\n");
break;
}
} else
dp_info->tries = 0;
voltage = dp_info->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
/* Compute new train_set as requested by sink */
dp_get_adjust_train(dp_info->link_status, dp_info->dp_lane_count, dp_info->train_set);
radeon_dp_update_vs_emph(dp_info);
}
if (!clock_recovery) {
DRM_ERROR("clock recovery failed\n");
return -1;
} else {
DRM_DEBUG_KMS("clock recovery at voltage %d pre-emphasis %d\n",
dp_info->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK,
(dp_info->train_set[0] & DP_TRAIN_PRE_EMPHASIS_MASK) >>
DP_TRAIN_PRE_EMPHASIS_SHIFT);
return 0;
}
}
