From 847a9038c2d025b32cd7ddcc2ccfa0e82a8ded53 Mon Sep 17 00:00:00 2001 From: Jimmy Kizito Date: Mon, 19 Apr 2021 15:12:01 -0400 Subject: [PATCH] drm/amd/display: Implement DPIA equalisation phase [Why] Equalisation is the mandatory second phase of DisplayPort link training over a USB4 DP tunnel. [How] Implement equalisation phase for DP tunneled over USB4 in DPIA training module. Reviewed-by: Jun Lei Acked-by: Wayne Lin Acked-by: Nicholas Kazlauskas Acked-by: Harry Wentland Signed-off-by: Jimmy Kizito Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c | 249 ++++++++++++++++++++- 1 file changed, 246 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c index 2bb78a3..9ecbe87 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c @@ -478,17 +478,260 @@ static enum link_training_result dpia_training_cr_phase(struct dc_link *link, return result; } +/* Return status read interval during equalization phase. */ +static uint32_t dpia_get_eq_aux_rd_interval(const struct dc_link *link, + const struct link_training_settings *lt_settings, + uint32_t hop) +{ + uint32_t wait_time_microsec; + + if (hop == DPRX) + wait_time_microsec = lt_settings->eq_pattern_time; + else + wait_time_microsec = + dp_translate_training_aux_read_interval( + link->dpcd_caps.lttpr_caps.aux_rd_interval[hop - 1]); + + return wait_time_microsec; +} + +/* Execute equalization phase of link training for specified hop in display + * path in non-transparent mode: + * - driver issues both DPCD and SET_CONFIG transactions. + * - TPSx is transmitted for any hops downstream of DPOA. + * - Drive (VS/PE) only transmitted for the hop immediately downstream of DPOA. + * - EQ for the first hop (DPTX-to-DPIA) is assumed to be successful. + * - DPRX EQ only reported successful when both DPRX and DPIA requirements + * (clk sync packets sent) fulfilled. + * + * @param link DPIA link being trained. + * @param lt_settings link_setting and drive settings (voltage swing and pre-emphasis). + * @param hop The Hop in display path. DPRX = 0. + */ +static enum link_training_result dpia_training_eq_non_transparent(struct dc_link *link, + struct link_training_settings *lt_settings, + uint32_t hop) +{ + enum link_training_result result = LINK_TRAINING_EQ_FAIL_EQ; + uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */ + uint32_t retries_eq = 0; + enum dc_status status; + enum dc_dp_training_pattern tr_pattern; + uint32_t wait_time_microsec; + struct link_training_settings req_settings; + enum dc_lane_count lane_count = lt_settings->link_settings.lane_count; + union lane_align_status_updated dpcd_lane_status_updated = { {0} }; + union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = { { {0} } }; + uint8_t set_cfg_data; + enum dpia_set_config_ts ts; + + /* Training pattern is TPS4 for repeater; + * TPS2/3/4 for DPRX depending on what it supports. + */ + if (hop == DPRX) + tr_pattern = lt_settings->pattern_for_eq; + else + tr_pattern = DP_TRAINING_PATTERN_SEQUENCE_4; + + repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt); + + for (retries_eq = 0; retries_eq < LINK_TRAINING_MAX_RETRY_COUNT; retries_eq++) { + /* DPTX-to-DPIA equalization always successful. */ + if (hop == repeater_cnt) { + result = LINK_TRAINING_SUCCESS; + break; + } + + /* Instruct DPOA to transmit TPSn then update DPCD. */ + if (retries_eq == 0) { + ts = convert_trng_ptn_to_trng_stg(tr_pattern); + status = core_link_send_set_config(link, + DPIA_SET_CFG_SET_TRAINING, + ts); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + status = dpcd_set_lt_pattern(link, tr_pattern, hop); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + } + + /* Update DPOA drive settings then DPCD. DPOA only adjusts + * drive settings for hop immediately downstream. + */ + if (hop == repeater_cnt - 1) { + set_cfg_data = dpia_build_set_config_data(DPIA_SET_CFG_SET_VSPE, + link, + lt_settings); + status = core_link_send_set_config(link, + DPIA_SET_CFG_SET_VSPE, + set_cfg_data); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + } + status = dpcd_set_lane_settings(link, lt_settings, hop); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + + /* Extend wait time on second equalisation attempt on final hop to + * ensure clock sync packets have been sent. + */ + if (hop == DPRX && retries_eq == 1) + wait_time_microsec = max(wait_time_microsec, (uint32_t)DPIA_CLK_SYNC_DELAY); + else + wait_time_microsec = dpia_get_eq_aux_rd_interval(link, lt_settings, hop); + + dp_wait_for_training_aux_rd_interval(link, wait_time_microsec); + + /* Read status and adjustment requests from DPCD. */ + status = dp_get_lane_status_and_drive_settings(link, + lt_settings, + dpcd_lane_status, + &dpcd_lane_status_updated, + &req_settings, + hop); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + + /* CR can still fail during EQ phase. Fail training if CR fails. */ + if (!dp_is_cr_done(lane_count, dpcd_lane_status)) { + result = LINK_TRAINING_EQ_FAIL_CR; + break; + } + + if (dp_is_ch_eq_done(lane_count, dpcd_lane_status) && + dp_is_symbol_locked(link->cur_link_settings.lane_count, dpcd_lane_status) && + dp_is_interlane_aligned(dpcd_lane_status_updated)) { + result = LINK_TRAINING_SUCCESS; + break; + } + + /* Update VS/PE. */ + dp_update_drive_settings(lt_settings, req_settings); + } + + /* Abort link training if equalization failed due to HPD unplug. */ + if (!link->hpd_status) + result = LINK_TRAINING_ABORT; + + DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) equalization\n" + " - hop(%d)\n - result(%d)\n - retries(%d)\n", + __func__, + link->link_id.enum_id - ENUM_ID_1, + hop, + result, + retries_eq); + + return result; +} + +/* Execute equalization phase of link training for specified hop in display + * path in transparent LTTPR mode: + * - driver only issues DPCD transactions leaves USB4 tunneling (SET_CONFIG) messages to DPIA. + * - driver writes TPSx to DPCD to notify DPIA that is in equalization phase. + * - equalization (EQ) for link is handled by DPOA, which reports result to DPIA on completion. + * - DPIA communicates result to driver by updating EQ status when driver reads DPCD. + * + * @param link DPIA link being trained. + * @param lt_settings link_setting and drive settings (voltage swing and pre-emphasis). + * @param hop The Hop in display path. DPRX = 0. + */ +static enum link_training_result dpia_training_eq_transparent(struct dc_link *link, + struct link_training_settings *lt_settings) +{ + enum link_training_result result = LINK_TRAINING_EQ_FAIL_EQ; + uint32_t retries_eq = 0; + enum dc_status status; + enum dc_dp_training_pattern tr_pattern = lt_settings->pattern_for_eq; + uint32_t wait_time_microsec; + struct link_training_settings req_settings; + enum dc_lane_count lane_count = lt_settings->link_settings.lane_count; + union lane_align_status_updated dpcd_lane_status_updated = { {0} }; + union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = { { {0} } }; + + wait_time_microsec = dpia_get_eq_aux_rd_interval(link, lt_settings, DPRX); + + for (retries_eq = 0; retries_eq < LINK_TRAINING_MAX_RETRY_COUNT; retries_eq++) { + if (retries_eq == 0) { + status = dpcd_set_lt_pattern(link, tr_pattern, DPRX); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + } + + dp_wait_for_training_aux_rd_interval(link, wait_time_microsec); + + /* Read status and adjustment requests from DPCD. */ + status = dp_get_lane_status_and_drive_settings(link, + lt_settings, + dpcd_lane_status, + &dpcd_lane_status_updated, + &req_settings, + DPRX); + if (status != DC_OK) { + result = LINK_TRAINING_ABORT; + break; + } + + /* CR can still fail during EQ phase. Fail training if CR fails. */ + if (!dp_is_cr_done(lane_count, dpcd_lane_status)) { + result = LINK_TRAINING_EQ_FAIL_CR; + break; + } + + if (dp_is_ch_eq_done(lane_count, dpcd_lane_status) && + dp_is_symbol_locked(link->cur_link_settings.lane_count, dpcd_lane_status) && + dp_is_interlane_aligned(dpcd_lane_status_updated)) { + result = LINK_TRAINING_SUCCESS; + break; + } + + /* Update VS/PE. */ + dp_update_drive_settings(lt_settings, req_settings); + } + + /* Abort link training if equalization failed due to HPD unplug. */ + if (!link->hpd_status) + result = LINK_TRAINING_ABORT; + + DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) equalization\n" + " - hop(%d)\n - result(%d)\n - retries(%d)\n", + __func__, + link->link_id.enum_id - ENUM_ID_1, + DPRX, + result, + retries_eq); + + return result; +} + /* Execute equalization phase of link training for specified hop in display * path. + * + * @param link DPIA link being trained. + * @param lt_settings link_setting and drive settings (voltage swing and pre-emphasis). + * @param hop The Hop in display path. DPRX = 0. */ static enum link_training_result dpia_training_eq_phase(struct dc_link *link, struct link_training_settings *lt_settings, uint32_t hop) { - enum link_training_result result; + enum link_training_result result = LINK_TRAINING_EQ_FAIL_EQ; - /** @todo Fail until implemented. */ - result = LINK_TRAINING_ABORT; + if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) + result = dpia_training_eq_non_transparent(link, lt_settings, hop); + else + result = dpia_training_eq_transparent(link, lt_settings); return result; } -- 2.7.4