diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 153 |
1 files changed, 135 insertions, 18 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 4d0d1e8e51fa..ada0a1ff262d 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -154,38 +154,155 @@ u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZ } EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); -void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux, - const u8 dpcd[DP_RECEIVER_CAP_SIZE]) +static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) { - unsigned long rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & - DP_TRAINING_AUX_RD_MASK; - if (rd_interval > 4) - drm_dbg_kms(aux->drm_dev, "%s: AUX interval %lu, out of range (max 4)\n", + drm_dbg_kms(aux->drm_dev, "%s: invalid AUX interval 0x%02x (max 4)\n", aux->name, rd_interval); - if (rd_interval == 0 || dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) - rd_interval = 100; - else - rd_interval *= 4 * USEC_PER_MSEC; + if (rd_interval == 0) + return 100; - usleep_range(rd_interval, rd_interval * 2); + return rd_interval * 4 * USEC_PER_MSEC; } -EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); -static void __drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux, - unsigned long rd_interval) +static int __8b10b_channel_eq_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) { if (rd_interval > 4) - drm_dbg_kms(aux->drm_dev, "%s: AUX interval %lu, out of range (max 4)\n", + drm_dbg_kms(aux->drm_dev, "%s: invalid AUX interval 0x%02x (max 4)\n", aux->name, rd_interval); if (rd_interval == 0) - rd_interval = 400; + return 400; + + return rd_interval * 4 * USEC_PER_MSEC; +} + +static int __128b132b_channel_eq_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) +{ + switch (rd_interval) { + default: + drm_dbg_kms(aux->drm_dev, "%s: invalid AUX interval 0x%02x\n", + aux->name, rd_interval); + fallthrough; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_400_US: + return 400; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_4_MS: + return 4000; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_8_MS: + return 8000; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_12_MS: + return 12000; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_16_MS: + return 16000; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_32_MS: + return 32000; + case DP_128B132B_TRAINING_AUX_RD_INTERVAL_64_MS: + return 64000; + } +} + +/* + * The link training delays are different for: + * + * - Clock recovery vs. channel equalization + * - DPRX vs. LTTPR + * - 128b/132b vs. 8b/10b + * - DPCD rev 1.3 vs. later + * + * Get the correct delay in us, reading DPCD if necessary. + */ +static int __read_delay(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE], + enum drm_dp_phy dp_phy, bool uhbr, bool cr) +{ + int (*parse)(const struct drm_dp_aux *aux, u8 rd_interval); + unsigned int offset; + u8 rd_interval, mask; + + if (dp_phy == DP_PHY_DPRX) { + if (uhbr) { + if (cr) + return 100; + + offset = DP_128B132B_TRAINING_AUX_RD_INTERVAL; + mask = DP_128B132B_TRAINING_AUX_RD_INTERVAL_MASK; + parse = __128b132b_channel_eq_delay_us; + } else { + if (cr && dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) + return 100; + + offset = DP_TRAINING_AUX_RD_INTERVAL; + mask = DP_TRAINING_AUX_RD_MASK; + if (cr) + parse = __8b10b_clock_recovery_delay_us; + else + parse = __8b10b_channel_eq_delay_us; + } + } else { + if (uhbr) { + offset = DP_128B132B_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER(dp_phy); + mask = DP_128B132B_TRAINING_AUX_RD_INTERVAL_MASK; + parse = __128b132b_channel_eq_delay_us; + } else { + if (cr) + return 100; + + offset = DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER(dp_phy); + mask = DP_TRAINING_AUX_RD_MASK; + parse = __8b10b_channel_eq_delay_us; + } + } + + if (offset < DP_RECEIVER_CAP_SIZE) { + rd_interval = dpcd[offset]; + } else { + if (drm_dp_dpcd_readb(aux, offset, &rd_interval) != 1) { + drm_dbg_kms(aux->drm_dev, "%s: failed rd interval read\n", + aux->name); + /* arbitrary default delay */ + return 400; + } + } + + return parse(aux, rd_interval & mask); +} + +int drm_dp_read_clock_recovery_delay(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE], + enum drm_dp_phy dp_phy, bool uhbr) +{ + return __read_delay(aux, dpcd, dp_phy, uhbr, true); +} +EXPORT_SYMBOL(drm_dp_read_clock_recovery_delay); + +int drm_dp_read_channel_eq_delay(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE], + enum drm_dp_phy dp_phy, bool uhbr) +{ + return __read_delay(aux, dpcd, dp_phy, uhbr, false); +} +EXPORT_SYMBOL(drm_dp_read_channel_eq_delay); + +void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux, + const u8 dpcd[DP_RECEIVER_CAP_SIZE]) +{ + u8 rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & + DP_TRAINING_AUX_RD_MASK; + int delay_us; + + if (dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) + delay_us = 100; else - rd_interval *= 4 * USEC_PER_MSEC; + delay_us = __8b10b_clock_recovery_delay_us(aux, rd_interval); + + usleep_range(delay_us, delay_us * 2); +} +EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); + +static void __drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux, + u8 rd_interval) +{ + int delay_us = __8b10b_channel_eq_delay_us(aux, rd_interval); - usleep_range(rd_interval, rd_interval * 2); + usleep_range(delay_us, delay_us * 2); } void drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux, |