[PATCH 11/16] drm/amd/display: Add vendor specific LTTPR workarounds for DCN31
Bhawanpreet Lakha
Bhawanpreet.Lakha at amd.com
Fri Nov 26 19:49:17 UTC 2021
From: George Shen <George.Shen at amd.com>
[Why]
Certain LTTPR require special workarounds in order to comply
with DP specifications.
[How]
Implement vendor specific sequences via DPCD writes to
vendor-specific LTTPR registers.
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
Signed-off-by: George Shen <George.Shen at amd.com>
---
.../gpu/drm/amd/display/dc/core/dc_link_dp.c | 196 +++++++++++++++++-
drivers/gpu/drm/amd/display/dc/dc.h | 1 +
drivers/gpu/drm/amd/display/dc/dc_link.h | 3 +
.../drm/amd/display/dc/dcn31/dcn31_resource.c | 1 +
4 files changed, 198 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index ee9b80809fc5..5eea4ec82f99 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -398,6 +398,170 @@ static uint8_t get_dpcd_link_rate(const struct dc_link_settings *link_settings)
}
#endif
+static void vendor_specific_lttpr_wa_one_start(struct dc_link *link)
+{
+ const uint8_t vendor_lttpr_write_data[4] = {0x1, 0x50, 0x63, 0xff};
+ const uint8_t offset = dp_convert_to_count(
+ link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+ uint32_t vendor_lttpr_write_address = 0xF004F;
+
+ if (offset != 0xFF)
+ vendor_lttpr_write_address +=
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ /* W/A for certain LTTPR to reset their lane settings, part one of two */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data[0],
+ sizeof(vendor_lttpr_write_data));
+}
+
+static void vendor_specific_lttpr_wa_one_end(
+ struct dc_link *link,
+ uint8_t retry_count)
+{
+ const uint8_t vendor_lttpr_write_data[4] = {0x1, 0x50, 0x63, 0x0};
+ const uint8_t offset = dp_convert_to_count(
+ link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+ uint32_t vendor_lttpr_write_address = 0xF004F;
+
+ if (!retry_count) {
+ if (offset != 0xFF)
+ vendor_lttpr_write_address +=
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ /* W/A for certain LTTPR to reset their lane settings, part two of two */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data[0],
+ sizeof(vendor_lttpr_write_data));
+ }
+}
+
+static void vendor_specific_lttpr_wa_one_two(
+ struct dc_link *link,
+ const uint8_t rate)
+{
+ uint8_t toggle_rate = 0x0;
+
+ if (rate == 0x6)
+ toggle_rate = 0xA;
+ else
+ toggle_rate = 0x6;
+
+ if (link->vendor_specific_lttpr_link_rate_wa == rate) {
+ /* W/A for certain LTTPR to reset internal state for link training */
+ core_link_write_dpcd(
+ link,
+ DP_LINK_BW_SET,
+ &toggle_rate,
+ 1);
+ }
+
+ /* Store the last attempted link rate for this link */
+ link->vendor_specific_lttpr_link_rate_wa = rate;
+}
+
+static void vendor_specific_lttpr_wa_three(
+ struct dc_link *link,
+ union lane_adjust dpcd_lane_adjust[LANE_COUNT_DP_MAX])
+{
+ const uint8_t vendor_lttpr_write_data_vs[3] = {0x0, 0x53, 0x63};
+ const uint8_t vendor_lttpr_write_data_pe[3] = {0x0, 0x54, 0x63};
+ const uint8_t offset = dp_convert_to_count(
+ link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+ uint32_t vendor_lttpr_write_address = 0xF004F;
+ uint32_t vendor_lttpr_read_address = 0xF0053;
+ uint8_t dprx_vs = 0;
+ uint8_t dprx_pe = 0;
+ uint8_t lane;
+
+ if (offset != 0xFF) {
+ vendor_lttpr_write_address +=
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+ vendor_lttpr_read_address +=
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+ }
+
+ /* W/A to read lane settings requested by DPRX */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_vs[0],
+ sizeof(vendor_lttpr_write_data_vs));
+ core_link_read_dpcd(
+ link,
+ vendor_lttpr_read_address,
+ &dprx_vs,
+ 1);
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_pe[0],
+ sizeof(vendor_lttpr_write_data_pe));
+ core_link_read_dpcd(
+ link,
+ vendor_lttpr_read_address,
+ &dprx_pe,
+ 1);
+
+ for (lane = 0; lane < LANE_COUNT_DP_MAX; lane++) {
+ dpcd_lane_adjust[lane].bits.VOLTAGE_SWING_LANE = (dprx_vs >> (2 * lane)) & 0x3;
+ dpcd_lane_adjust[lane].bits.PRE_EMPHASIS_LANE = (dprx_pe >> (2 * lane)) & 0x3;
+ }
+}
+
+static void vendor_specific_lttpr_wa_four(
+ struct dc_link *link,
+ bool apply_wa)
+{
+ const uint8_t vendor_lttpr_write_data_one[4] = {0x1, 0x55, 0x63, 0x8};
+ const uint8_t vendor_lttpr_write_data_two[4] = {0x1, 0x55, 0x63, 0x0};
+ const uint8_t offset = dp_convert_to_count(
+ link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+ uint32_t vendor_lttpr_write_address = 0xF004F;
+#if defined(CONFIG_DRM_AMD_DC_DP2_0)
+ uint8_t sink_status = 0;
+ uint8_t i;
+#endif
+
+ if (offset != 0xFF)
+ vendor_lttpr_write_address +=
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ /* W/A to pass through DPCD write of TPS=0 to DPRX */
+ if (apply_wa) {
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_one[0],
+ sizeof(vendor_lttpr_write_data_one));
+ }
+
+ /* clear training pattern set */
+ dpcd_set_training_pattern(link, DP_TRAINING_PATTERN_VIDEOIDLE);
+
+ if (apply_wa) {
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_two[0],
+ sizeof(vendor_lttpr_write_data_two));
+ }
+
+#if defined(CONFIG_DRM_AMD_DC_DP2_0)
+ /* poll for intra-hop disable */
+ for (i = 0; i < 10; i++) {
+ if ((core_link_read_dpcd(link, DP_SINK_STATUS, &sink_status, 1) == DC_OK) &&
+ (sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION) == 0)
+ break;
+ udelay(1000);
+ }
+#endif
+}
+
enum dc_status dpcd_set_link_settings(
struct dc_link *link,
const struct link_training_settings *lt_settings)
@@ -452,6 +616,13 @@ enum dc_status dpcd_set_link_settings(
#else
rate = (uint8_t) (lt_settings->link_settings.link_rate);
#endif
+ if (link->dc->debug.apply_vendor_specific_lttpr_wa &&
+ (link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+ link->lttpr_mode == LTTPR_MODE_TRANSPARENT) {
+ vendor_specific_lttpr_wa_one_start(link);
+ vendor_specific_lttpr_wa_one_two(link, rate);
+ }
+
status = core_link_write_dpcd(link, DP_LINK_BW_SET, &rate, 1);
}
@@ -1329,6 +1500,13 @@ static enum link_training_result perform_clock_recovery_sequence(
dpcd_lane_adjust,
offset);
+ if (link->dc->debug.apply_vendor_specific_lttpr_wa &&
+ (link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+ link->lttpr_mode == LTTPR_MODE_TRANSPARENT) {
+ vendor_specific_lttpr_wa_one_end(link, retry_count);
+ vendor_specific_lttpr_wa_three(link, dpcd_lane_adjust);
+ }
+
/* 5. check CR done*/
if (dp_is_cr_done(lane_count, dpcd_lane_status))
return LINK_TRAINING_SUCCESS;
@@ -2203,7 +2381,12 @@ enum link_training_result dc_link_dp_perform_link_training(
<_settings);
/* reset previous training states */
- dpcd_exit_training_mode(link);
+ if (link->dc->debug.apply_vendor_specific_lttpr_wa &&
+ (link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+ link->lttpr_mode == LTTPR_MODE_TRANSPARENT)
+ vendor_specific_lttpr_wa_four(link, true);
+ else
+ dpcd_exit_training_mode(link);
/* configure link prior to entering training mode */
dpcd_configure_lttpr_mode(link, <_settings);
@@ -2223,8 +2406,15 @@ enum link_training_result dc_link_dp_perform_link_training(
else
ASSERT(0);
- /* exit training mode and switch to video idle */
- dpcd_exit_training_mode(link);
+ /* exit training mode */
+ if (link->dc->debug.apply_vendor_specific_lttpr_wa &&
+ (link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+ link->lttpr_mode == LTTPR_MODE_TRANSPARENT)
+ vendor_specific_lttpr_wa_four(link, (status != LINK_TRAINING_SUCCESS));
+ else
+ dpcd_exit_training_mode(link);
+
+ /* switch to video idle */
if ((status == LINK_TRAINING_SUCCESS) || !skip_video_pattern)
status = dp_transition_to_video_idle(link,
<_settings,
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index 1738556c9b59..9f5745313e48 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -696,6 +696,7 @@ struct dc_debug_options {
bool enable_sw_cntl_psr;
union dpia_debug_options dpia_debug;
#endif
+ bool apply_vendor_specific_lttpr_wa;
};
struct gpu_info_soc_bounding_box_v1_0;
diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index 30822aa33931..a99950883e85 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -186,6 +186,9 @@ struct dc_link {
/* Drive settings read from integrated info table */
struct dc_lane_settings bios_forced_drive_settings;
+ /* Vendor specific LTTPR workaround variables */
+ uint8_t vendor_specific_lttpr_link_rate_wa;
+
/* MST record stream using this link */
struct link_flags {
bool dp_keep_receiver_powered;
diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
index 70cbd89bdcb8..6187c55ac82c 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
@@ -1023,6 +1023,7 @@ static const struct dc_debug_options debug_defaults_drv = {
},
.optimize_edp_link_rate = true,
.enable_sw_cntl_psr = true,
+ .apply_vendor_specific_lttpr_wa = true,
};
static const struct dc_debug_options debug_defaults_diags = {
--
2.25.1
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