[PATCH 11/21] drm/amd/display: Enumerate LTTPR modes
Anson Jacob
Anson.Jacob at amd.com
Fri Mar 26 22:05:24 UTC 2021
From: Wesley Chalmers <Wesley.Chalmers at amd.com>
[WHY]
There are three possible modes for LTTPR:
- Non-LTTPR mode, where AUX timeout is 400 us and no per-hop link
training is done
- LTTPR Transparent mode, where AUX timeout is 3200 us and no per-hop
link training is done
- LTTPR Non-Transparent mode, where AUX timeout is 3200 us and per-hop
link training is done
[HOW]
Use an enum instead of a bool to track LTTPR state; modify comparisons
accordingly.
Signed-off-by: Wesley Chalmers <Wesley.Chalmers at amd.com>
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Acked-by: Anson Jacob <Anson.Jacob at amd.com>
---
.../gpu/drm/amd/display/dc/core/dc_link_dp.c | 33 +++++++++++++------
.../drm/amd/display/dc/core/dc_link_hwss.c | 2 +-
drivers/gpu/drm/amd/display/dc/dc_link.h | 9 ++++-
3 files changed, 32 insertions(+), 12 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 962e88dd8dda..209286357867 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
@@ -284,7 +284,7 @@ static uint8_t dc_dp_initialize_scrambling_data_symbols(
static inline bool is_repeater(struct dc_link *link, uint32_t offset)
{
- return (link->lttpr_non_transparent_mode && offset != 0);
+ return (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) && (offset != 0);
}
static void dpcd_set_lt_pattern_and_lane_settings(
@@ -1072,7 +1072,7 @@ static enum link_training_result perform_clock_recovery_sequence(
/* 3. wait receiver to lock-on*/
wait_time_microsec = lt_settings->cr_pattern_time;
- if (link->lttpr_non_transparent_mode)
+ if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
wait_time_microsec = TRAINING_AUX_RD_INTERVAL;
wait_for_training_aux_rd_interval(
@@ -1326,7 +1326,17 @@ static uint8_t convert_to_count(uint8_t lttpr_repeater_count)
return 0; // invalid value
}
-static void configure_lttpr_mode(struct dc_link *link)
+static void configure_lttpr_mode_transparent(struct dc_link *link)
+{
+ uint8_t repeater_mode = DP_PHY_REPEATER_MODE_TRANSPARENT;
+
+ core_link_write_dpcd(link,
+ DP_PHY_REPEATER_MODE,
+ (uint8_t *)&repeater_mode,
+ sizeof(repeater_mode));
+}
+
+static void configure_lttpr_mode_non_transparent(struct dc_link *link)
{
/* aux timeout is already set to extended */
/* RESET/SET lttpr mode to enable non transparent mode */
@@ -1346,7 +1356,7 @@ static void configure_lttpr_mode(struct dc_link *link)
link->dpcd_caps.lttpr_caps.mode = repeater_mode;
}
- if (link->lttpr_non_transparent_mode) {
+ if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
DC_LOG_HW_LINK_TRAINING("%s\n Set LTTPR to Non Transparent Mode\n", __func__);
@@ -1562,8 +1572,10 @@ enum link_training_result dc_link_dp_perform_link_training(
<_settings);
/* Configure lttpr mode */
- if (link->lttpr_non_transparent_mode)
- configure_lttpr_mode(link);
+ if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
+ configure_lttpr_mode_non_transparent(link);
+ else if (link->lttpr_mode == LTTPR_MODE_TRANSPARENT)
+ configure_lttpr_mode_transparent(link);
if (link->ctx->dc->work_arounds.lt_early_cr_pattern)
start_clock_recovery_pattern_early(link, <_settings, DPRX);
@@ -1578,7 +1590,7 @@ enum link_training_result dc_link_dp_perform_link_training(
dp_set_fec_ready(link, fec_enable);
- if (link->lttpr_non_transparent_mode) {
+ if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
/* 2. perform link training (set link training done
* to false is done as well)
@@ -1899,7 +1911,7 @@ static struct dc_link_settings get_max_link_cap(struct dc_link *link)
* account for lttpr repeaters cap
* notes: repeaters do not snoop in the DPRX Capabilities addresses (3.6.3).
*/
- if (link->lttpr_non_transparent_mode) {
+ if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
if (link->dpcd_caps.lttpr_caps.max_lane_count < max_link_cap.lane_count)
max_link_cap.lane_count = link->dpcd_caps.lttpr_caps.max_lane_count;
@@ -2057,7 +2069,7 @@ bool dp_verify_link_cap(
max_link_cap = get_max_link_cap(link);
/* Grant extended timeout request */
- if (link->lttpr_non_transparent_mode && link->dpcd_caps.lttpr_caps.max_ext_timeout > 0) {
+ if ((link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) && (link->dpcd_caps.lttpr_caps.max_ext_timeout > 0)) {
uint8_t grant = link->dpcd_caps.lttpr_caps.max_ext_timeout & 0x80;
core_link_write_dpcd(link, DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT, &grant, sizeof(grant));
@@ -3529,7 +3541,8 @@ static bool retrieve_link_cap(struct dc_link *link)
}
/* decide lttpr non transparent mode */
- link->lttpr_non_transparent_mode = is_lttpr_present;
+ /*This is a temporary placeholder for LTTPR logic. More comprehensive logic will be added in a future change*/
+ link->lttpr_mode = is_lttpr_present ? LTTPR_MODE_NON_TRANSPARENT : LTTPR_MODE_NON_LTTPR;
if (!is_lttpr_present)
dc_link_aux_try_to_configure_timeout(link->ddc, LINK_AUX_DEFAULT_TIMEOUT_PERIOD);
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
index 124ce215fca5..22fe19ee842d 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
@@ -302,7 +302,7 @@ void dp_set_hw_lane_settings(
{
struct link_encoder *encoder = link->link_enc;
- if (link->lttpr_non_transparent_mode && !is_immediate_downstream(link, offset))
+ if ((link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) && !is_immediate_downstream(link, offset))
return;
/* call Encoder to set lane settings */
diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index c50ef5a909a6..7b927e634279 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -35,6 +35,13 @@ enum dc_link_fec_state {
dc_link_fec_ready,
dc_link_fec_enabled
};
+
+enum lttpr_mode {
+ LTTPR_MODE_NON_LTTPR,
+ LTTPR_MODE_TRANSPARENT,
+ LTTPR_MODE_NON_TRANSPARENT,
+};
+
struct dc_link_status {
bool link_active;
struct dpcd_caps *dpcd_caps;
@@ -100,7 +107,7 @@ struct dc_link {
bool link_state_valid;
bool aux_access_disabled;
bool sync_lt_in_progress;
- bool lttpr_non_transparent_mode;
+ enum lttpr_mode lttpr_mode;
bool is_internal_display;
/* TODO: Rename. Flag an endpoint as having a programmable mapping to a
--
2.25.1
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