Hi
This patch is giving me a build error with Werror when building with Clang-13
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:195:2:
error: variable 'ts' is used uninitialized whenever switch default is
taken [-Werror,-Wsometimes-uninitialized]
default:
^~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:200:9:
note: uninitialized use occurs here
return ts;
^~
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:180:2:
note: variable 'ts' is declared here
enum dpia_set_config_ts ts;
^
1 error generated.
Cheers
Mike
On Tue, 5 Oct 2021 at 08:57, Wayne Lin <Wayne.Lin@xxxxxxx> wrote:
>
> From: Jimmy Kizito <Jimmy.Kizito@xxxxxxx>
>
> [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@xxxxxxx>
> Acked-by: Wayne Lin <Wayne.Lin@xxxxxxx>
> Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
> Signed-off-by: Jimmy Kizito <Jimmy.Kizito@xxxxxxx>
> ---
> .../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
>
