[PATCH v2 11/23] drm/amd/display: Implement DPIA clock recovery phase
Wayne Lin
Wayne.Lin at amd.com
Tue Oct 5 07:51:53 UTC 2021
From: Jimmy Kizito <Jimmy.Kizito at amd.com>
[Why]
Clock recovery is the mandatory first phase of DP link training.
[How]
- Implement clock recovery phase in DPIA training module.
- Add helper functions for building SET_CONFIG messages.
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Acked-by: Wayne Lin <Wayne.Lin at amd.com>
Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
Signed-off-by: Jimmy Kizito <Jimmy.Kizito at amd.com>
---
.../drm/amd/display/dc/core/dc_link_dpia.c | 420 +++++++++++++++++-
.../gpu/drm/amd/display/dc/inc/dc_link_dpia.h | 40 ++
2 files changed, 453 insertions(+), 7 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 5ffaf6ca372b..9608fd345936 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
@@ -28,6 +28,9 @@
#include "inc/core_status.h"
#include "dc_link.h"
#include "dc_link_dp.h"
+#include "dpcd_defs.h"
+#include "link_hwss.h"
+#include "inc/link_dpcd.h"
#define DC_LOGGER \
link->ctx->logger
@@ -87,17 +90,385 @@ static enum link_training_result dpia_configure_link(struct dc_link *link,
return LINK_TRAINING_SUCCESS;
}
+static enum dc_status core_link_send_set_config(struct dc_link *link,
+ uint8_t msg_type, uint8_t msg_data)
+{
+ /** @todo Implement */
+ return DC_OK;
+}
+
+/* Build SET_CONFIG message data payload for specified message type. */
+static uint8_t dpia_build_set_config_data(enum dpia_set_config_type type,
+ struct dc_link *link,
+ struct link_training_settings *lt_settings)
+{
+ union dpia_set_config_data data;
+
+ data.raw = 0;
+
+ switch (type) {
+ case DPIA_SET_CFG_SET_LINK:
+ data.set_link.mode = link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT ? 1 : 0;
+ break;
+ case DPIA_SET_CFG_SET_PHY_TEST_MODE:
+ break;
+ case DPIA_SET_CFG_SET_VSPE:
+ /* Assume all lanes have same drive settings. */
+ data.set_vspe.swing = lt_settings->lane_settings[0].VOLTAGE_SWING;
+ data.set_vspe.pre_emph = lt_settings->lane_settings[0].PRE_EMPHASIS;
+ data.set_vspe.max_swing_reached =
+ lt_settings->lane_settings[0].VOLTAGE_SWING == VOLTAGE_SWING_MAX_LEVEL ? 1 : 0;
+ data.set_vspe.max_pre_emph_reached =
+ lt_settings->lane_settings[0].PRE_EMPHASIS == PRE_EMPHASIS_MAX_LEVEL ? 1 : 0;
+ break;
+ default:
+ ASSERT(false); /* Message type not supported by helper function. */
+ break;
+ }
+
+ return data.raw;
+}
+
+/* Convert DC training pattern to DPIA training stage. */
+static enum dpia_set_config_ts convert_trng_ptn_to_trng_stg(enum dc_dp_training_pattern tps)
+{
+ enum dpia_set_config_ts ts;
+
+ switch (tps) {
+ case DP_TRAINING_PATTERN_SEQUENCE_1:
+ ts = DPIA_TS_TPS1;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_2:
+ ts = DPIA_TS_TPS2;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_3:
+ ts = DPIA_TS_TPS3;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_4:
+ ts = DPIA_TS_TPS4;
+ break;
+ default:
+ ASSERT(false); /* TPS not supported by helper function. */
+ break;
+ }
+
+ return ts;
+}
+
+/* Write training pattern to DPCD. */
+static enum dc_status dpcd_set_lt_pattern(struct dc_link *link,
+ enum dc_dp_training_pattern pattern,
+ uint32_t hop)
+{
+ union dpcd_training_pattern dpcd_pattern = { {0} };
+ uint32_t dpcd_tps_offset = DP_TRAINING_PATTERN_SET;
+ enum dc_status status;
+
+ if (hop != DPRX)
+ dpcd_tps_offset = DP_TRAINING_PATTERN_SET_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (hop - 1));
+
+ /* DpcdAddress_TrainingPatternSet */
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET =
+ dc_dp_training_pattern_to_dpcd_training_pattern(link, pattern);
+
+ dpcd_pattern.v1_4.SCRAMBLING_DISABLE =
+ dc_dp_initialize_scrambling_data_symbols(link, pattern);
+
+ if (hop != DPRX) {
+ DC_LOG_HW_LINK_TRAINING("%s\n LTTPR Repeater ID: %d\n 0x%X pattern = %x\n",
+ __func__,
+ hop,
+ dpcd_tps_offset,
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+ } else {
+ DC_LOG_HW_LINK_TRAINING("%s\n 0x%X pattern = %x\n",
+ __func__,
+ dpcd_tps_offset,
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+ }
+
+ status = core_link_write_dpcd(link,
+ DP_TRAINING_PATTERN_SET,
+ &dpcd_pattern.raw,
+ sizeof(dpcd_pattern.raw));
+
+ return status;
+}
+
+/* Execute clock recovery phase of link training for specified hop in display
+ * path.in non-transparent mode:
+ * - Driver issues both DPCD and SET_CONFIG transactions.
+ * - TPS1 is transmitted for any hops downstream of DPOA.
+ * - Drive (VS/PE) only transmitted for the hop immediately downstream of DPOA.
+ * - CR for the first hop (DPTX-to-DPIA) is assumed to be successful.
+ *
+ * @param link DPIA link being trained.
+ * @param lt_settings link_setting and drive settings (voltage swing and pre-emphasis).
+ * @param hop Hop in display path. DPRX = 0.
+ */
+static enum link_training_result dpia_training_cr_non_transparent(struct dc_link *link,
+ struct link_training_settings *lt_settings,
+ uint32_t hop)
+{
+ enum link_training_result result = LINK_TRAINING_CR_FAIL_LANE0;
+ uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */
+ enum dc_status status;
+ uint32_t retries_cr = 0; /* Number of consecutive attempts with same VS or PE. */
+ uint32_t retry_count = 0;
+ /* From DP spec, CR read interval is always 100us. */
+ uint32_t wait_time_microsec = TRAINING_AUX_RD_INTERVAL;
+ struct link_training_settings req_settings;
+ enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;
+ union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = { { {0} } };
+ union lane_align_status_updated dpcd_lane_status_updated = { {0} };
+ uint8_t set_cfg_data;
+ enum dpia_set_config_ts ts;
+
+ repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+
+ /* Cap of LINK_TRAINING_MAX_CR_RETRY attempts at clock recovery.
+ * Fix inherited from perform_clock_recovery_sequence() -
+ * the DP equivalent of this function:
+ * Required for Synaptics MST hub which can put the LT in
+ * infinite loop by switching the VS between level 0 and level 1
+ * continuously.
+ */
+ while ((retries_cr < LINK_TRAINING_MAX_RETRY_COUNT) &&
+ (retry_count < LINK_TRAINING_MAX_CR_RETRY)) {
+ /* DPTX-to-DPIA */
+ if (hop == repeater_cnt) {
+ /* Send SET_CONFIG(SET_LINK:LC,LR,LTTPR) to notify DPOA that
+ * non-transparent link training has started.
+ * This also enables the transmission of clk_sync packets.
+ */
+ set_cfg_data = dpia_build_set_config_data(DPIA_SET_CFG_SET_LINK,
+ link,
+ lt_settings);
+ status = core_link_send_set_config(link,
+ DPIA_SET_CFG_SET_LINK,
+ set_cfg_data);
+ /* CR for this hop is considered successful as long as
+ * SET_CONFIG message is acknowledged by DPOA.
+ */
+ if (status == DC_OK)
+ result = LINK_TRAINING_SUCCESS;
+ else
+ result = LINK_TRAINING_ABORT;
+ break;
+ }
+
+ /* DPOA-to-x */
+ /* Instruct DPOA to transmit TPS1 then update DPCD. */
+ if (retry_count == 0) {
+ ts = convert_trng_ptn_to_trng_stg(lt_settings->pattern_for_cr);
+ 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, lt_settings->pattern_for_cr, hop);
+ if (status != DC_OK) {
+ result = LINK_TRAINING_ABORT;
+ break;
+ }
+ }
+
+ /* Update DPOA drive settings then DPCD. DPOA does only adjusts
+ * drive settings for hops 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;
+ }
+
+ 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;
+ }
+
+ /* Check if clock recovery successful. */
+ if (dp_is_cr_done(lane_count, dpcd_lane_status)) {
+ result = LINK_TRAINING_SUCCESS;
+ break;
+ }
+
+ result = dp_get_cr_failure(lane_count, dpcd_lane_status);
+
+ if (dp_is_max_vs_reached(lt_settings))
+ break;
+
+ /* Count number of attempts with same drive settings.
+ * Note: settings are the same for all lanes,
+ * so comparing first lane is sufficient.
+ */
+ if (lt_settings->lane_settings[0].VOLTAGE_SWING ==
+ req_settings.lane_settings[0].VOLTAGE_SWING &&
+ lt_settings->lane_settings[0].PRE_EMPHASIS ==
+ req_settings.lane_settings[0].PRE_EMPHASIS)
+ retries_cr++;
+ else
+ retries_cr = 0;
+
+ /* Update VS/PE. */
+ dp_update_drive_settings(lt_settings, req_settings);
+ retry_count++;
+ }
+
+ /* Abort link training if clock recovery failed due to HPD unplug. */
+ if (!link->hpd_status)
+ result = LINK_TRAINING_ABORT;
+
+ DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) clock recovery\n -hop(%d)\n - result(%d)\n - retries(%d)\n",
+ __func__,
+ link->link_id.enum_id - ENUM_ID_1,
+ hop,
+ result,
+ retry_count);
+
+ return result;
+}
+
+/* Execute clock recovery phase of link training in transparent LTTPR mode:
+ * - Driver only issues DPCD transactions and leaves USB4 tunneling (SET_CONFIG) messages to DPIA.
+ * - Driver writes TPS1 to DPCD to kick off training.
+ * - Clock recovery (CR) for link is handled by DPOA, which reports result to DPIA on completion.
+ * - DPIA communicates result to driver by updating CR status when driver reads DPCD.
+ *
+ * @param link DPIA link being trained.
+ * @param lt_settings link_setting and drive settings (voltage swing and pre-emphasis).
+ */
+static enum link_training_result dpia_training_cr_transparent(struct dc_link *link,
+ struct link_training_settings *lt_settings)
+{
+ enum link_training_result result = LINK_TRAINING_CR_FAIL_LANE0;
+ enum dc_status status;
+ uint32_t retries_cr = 0; /* Number of consecutive attempts with same VS or PE. */
+ uint32_t retry_count = 0;
+ uint32_t wait_time_microsec = lt_settings->cr_pattern_time;
+ struct link_training_settings req_settings;
+ enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;
+ union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = { { {0} } };
+ union lane_align_status_updated dpcd_lane_status_updated = { {0} };
+
+ /* Cap of LINK_TRAINING_MAX_CR_RETRY attempts at clock recovery.
+ * Fix inherited from perform_clock_recovery_sequence() -
+ * the DP equivalent of this function:
+ * Required for Synaptics MST hub which can put the LT in
+ * infinite loop by switching the VS between level 0 and level 1
+ * continuously.
+ */
+ while ((retries_cr < LINK_TRAINING_MAX_RETRY_COUNT) &&
+ (retry_count < LINK_TRAINING_MAX_CR_RETRY)) {
+ /* Write TPS1 (not VS or PE) to DPCD to start CR phase.
+ * DPIA sends SET_CONFIG(SET_LINK) to notify DPOA to
+ * start link training.
+ */
+ if (retry_count == 0) {
+ status = dpcd_set_lt_pattern(link, lt_settings->pattern_for_cr, 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;
+ }
+
+ /* Check if clock recovery successful. */
+ if (dp_is_cr_done(lane_count, dpcd_lane_status)) {
+ result = LINK_TRAINING_SUCCESS;
+ break;
+ }
+
+ result = dp_get_cr_failure(lane_count, dpcd_lane_status);
+
+ if (dp_is_max_vs_reached(lt_settings))
+ break;
+
+ /* Count number of attempts with same drive settings.
+ * Note: settings are the same for all lanes,
+ * so comparing first lane is sufficient.
+ */
+ if (lt_settings->lane_settings[0].VOLTAGE_SWING ==
+ req_settings.lane_settings[0].VOLTAGE_SWING &&
+ lt_settings->lane_settings[0].PRE_EMPHASIS ==
+ req_settings.lane_settings[0].PRE_EMPHASIS)
+ retries_cr++;
+ else
+ retries_cr = 0;
+
+ /* Update VS/PE. */
+ dp_update_drive_settings(lt_settings, req_settings);
+ retry_count++;
+ }
+
+ /* Abort link training if clock recovery failed due to HPD unplug. */
+ if (!link->hpd_status)
+ result = LINK_TRAINING_ABORT;
+
+ DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) clock recovery\n -hop(%d)\n - result(%d)\n - retries(%d)\n",
+ __func__,
+ link->link_id.enum_id - ENUM_ID_1,
+ DPRX,
+ result,
+ retry_count);
+
+ return result;
+}
+
/* Execute clock recovery 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 Hop in display path. DPRX = 0.
*/
static enum link_training_result dpia_training_cr_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_CR_FAIL_LANE0;
- /** @todo Fail until implemented. */
- result = LINK_TRAINING_ABORT;
+ if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
+ result = dpia_training_cr_non_transparent(link, lt_settings, hop);
+ else
+ result = dpia_training_cr_transparent(link, lt_settings);
return result;
}
@@ -129,6 +500,38 @@ static enum link_training_result dpia_training_end(struct dc_link *link,
return result;
}
+/* When aborting training of specified hop in display path, clean up by:
+ * - Attempting to clear DPCD TRAINING_PATTERN_SET, LINK_BW_SET and LANE_COUNT_SET.
+ * - Sending SET_CONFIG(SET_LINK) with lane count and link rate set to 0.
+ *
+ * @param link DPIA link being trained.
+ * @param hop Hop in display path. DPRX = 0.
+ */
+static void dpia_training_abort(struct dc_link *link, uint32_t hop)
+{
+ uint8_t data = 0;
+ uint32_t dpcd_tps_offset = DP_TRAINING_PATTERN_SET;
+
+ 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,
+ link->hpd_status);
+
+ /* Abandon clean-up if sink unplugged. */
+ if (!link->hpd_status)
+ return;
+
+ if (hop != DPRX)
+ dpcd_tps_offset = DP_TRAINING_PATTERN_SET_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (hop - 1));
+
+ core_link_write_dpcd(link, dpcd_tps_offset, &data, 1);
+ core_link_write_dpcd(link, DP_LINK_BW_SET, &data, 1);
+ core_link_write_dpcd(link, DP_LANE_COUNT_SET, &data, 1);
+ core_link_send_set_config(link, DPIA_SET_CFG_SET_LINK, data);
+}
+
enum link_training_result dc_link_dpia_perform_link_training(struct dc_link *link,
const struct dc_link_settings *link_setting,
bool skip_video_pattern)
@@ -166,14 +569,17 @@ enum link_training_result dc_link_dpia_perform_link_training(struct dc_link *lin
break;
}
- /* Double-check link status if training successful; gracefully stop
- * training of current hop if training failed for any reason other than
- * sink unplug.
+ /* Double-check link status if training successful; gracefully abort
+ * training of current hop if training failed due to message tunneling
+ * failure; end training of hop if training ended conventionally and
+ * falling back to lower bandwidth settings possible.
*/
if (result == LINK_TRAINING_SUCCESS) {
msleep(5);
result = dp_check_link_loss_status(link, <_settings);
- } else if (result != LINK_TRAINING_ABORT) {
+ } else if (result == LINK_TRAINING_ABORT) {
+ dpia_training_abort(link, repeater_id);
+ } else {
dpia_training_end(link, repeater_id);
}
return result;
diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h
index 1392eb689d1e..76b6b1e23575 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h
@@ -31,6 +31,46 @@
struct dc_link;
struct dc_link_settings;
+/* The approximate time (us) it takes to transmit 9 USB4 DP clock sync packets. */
+#define DPIA_CLK_SYNC_DELAY 16000
+
+/* SET_CONFIG message types sent by driver. */
+enum dpia_set_config_type {
+ DPIA_SET_CFG_SET_LINK = 0x01,
+ DPIA_SET_CFG_SET_PHY_TEST_MODE = 0x05,
+ DPIA_SET_CFG_SET_TRAINING = 0x18,
+ DPIA_SET_CFG_SET_VSPE = 0x19
+};
+
+/* Training stages (TS) in SET_CONFIG(SET_TRAINING) message. */
+enum dpia_set_config_ts {
+ DPIA_TS_DPRX_DONE = 0x00, /* Done training DPRX. */
+ DPIA_TS_TPS1 = 0x01,
+ DPIA_TS_TPS2 = 0x02,
+ DPIA_TS_TPS3 = 0x03,
+ DPIA_TS_TPS4 = 0x07,
+ DPIA_TS_UFP_DONE = 0xff /* Done training DPTX-to-DPIA hop. */
+};
+
+/* SET_CONFIG message data associated with messages sent by driver. */
+union dpia_set_config_data {
+ struct {
+ uint8_t mode : 1;
+ uint8_t reserved : 7;
+ } set_link;
+ struct {
+ uint8_t stage;
+ } set_training;
+ struct {
+ uint8_t swing : 2;
+ uint8_t max_swing_reached : 1;
+ uint8_t pre_emph : 2;
+ uint8_t max_pre_emph_reached : 1;
+ uint8_t reserved : 2;
+ } set_vspe;
+ uint8_t raw;
+};
+
/* Read tunneling device capability from DPCD and update link capability
* accordingly.
*/
--
2.25.1
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