drm/amd/display: Implement end of training for hop in DPIA display path

[Why & How]
Clear training pattern sequence for hop in display path once clock
recovery and equalization phases of DP tunnel link training completed.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 9b8fbf2..56aaab2 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -2389,14 +2389,21 @@ bool perform_link_training_with_retries(
                        dc_link_dp_perform_link_training_skip_aux(link, &current_setting);
                        return true;
                } else {
-                       if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA)
+                       /** @todo Consolidate USB4 DP and DPx.x training. */
+                       if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA) {
                                status = dc_link_dpia_perform_link_training(link,
                                                                            &current_setting,
                                                                            skip_video_pattern);
-                       else
+
+                               /* Transmit idle pattern once training successful. */
+                               if (status == LINK_TRAINING_SUCCESS)
+                                       dp_set_hw_test_pattern(link, DP_TEST_PATTERN_VIDEO_MODE,
+                                                              NULL, 0);
+                       } else {
                                status = dc_link_dp_perform_link_training(link,
                                                                          &current_setting,
                                                                          skip_video_pattern);
+                       }
 
                        if (status == LINK_TRAINING_SUCCESS)
                                return true;

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 9ecbe87..15dbea3 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c
@@ -737,13 +737,84 @@ static enum link_training_result dpia_training_eq_phase(struct dc_link *link,
 }
 
 /* End training of specified hop in display path. */
+static enum dc_status dpcd_clear_lt_pattern(struct dc_link *link, 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));
+
+       status = core_link_write_dpcd(link,
+                       DP_TRAINING_PATTERN_SET,
+                       &dpcd_pattern.raw,
+                       sizeof(dpcd_pattern.raw));
+
+       return status;
+}
+
+/* End training of specified hop in display path.
+ *
+ * In transparent LTTPR mode:
+ * - driver clears training pattern for the specified hop in DPCD.
+ * In non-transparent LTTPR mode:
+ * - in addition to clearing training pattern, driver issues USB4 tunneling
+ * (SET_CONFIG) messages to notify DPOA when training is done for first hop
+ * (DPTX-to-DPIA) and last hop (DPRX).
+ *
+ * @param link DPIA link being trained.
+ * @param hop The Hop in display path. DPRX = 0.
+ */
 static enum link_training_result dpia_training_end(struct dc_link *link,
                uint32_t hop)
 {
-       enum link_training_result result;
+       enum link_training_result result = LINK_TRAINING_SUCCESS;
+       uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */
+       enum dc_status status;
+
+       if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
+               repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
 
-       /** @todo Fail until implemented. */
-       result = LINK_TRAINING_ABORT;
+               if (hop == repeater_cnt) { /* DPTX-to-DPIA */
+                       /* Send SET_CONFIG(SET_TRAINING:0xff) to notify DPOA that
+                        * DPTX-to-DPIA hop trained. No DPCD write needed for first hop.
+                        */
+                       status = core_link_send_set_config(link,
+                                       DPIA_SET_CFG_SET_TRAINING,
+                                       DPIA_TS_UFP_DONE);
+                       if (status != DC_OK)
+                               result = LINK_TRAINING_ABORT;
+               } else { /* DPOA-to-x */
+                       /* Write 0x0 to TRAINING_PATTERN_SET */
+                       status = dpcd_clear_lt_pattern(link, hop);
+                       if (status != DC_OK)
+                               result = LINK_TRAINING_ABORT;
+               }
+
+               /* Notify DPOA that non-transparent link training of DPRX done. */
+               if (hop == DPRX && result != LINK_TRAINING_ABORT) {
+                       status = core_link_send_set_config(link,
+                                       DPIA_SET_CFG_SET_TRAINING,
+                                       DPIA_TS_DPRX_DONE);
+                       if (status != DC_OK)
+                               result = LINK_TRAINING_ABORT;
+               }
+
+       } else { /* non-LTTPR or transparent LTTPR. */
+               /* Write 0x0 to TRAINING_PATTERN_SET */
+               status = dpcd_clear_lt_pattern(link, hop);
+               if (status != DC_OK)
+                       result = LINK_TRAINING_ABORT;
+       }
+
+       DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) end\n - hop(%d)\n - result(%d)\n - LTTPR mode(%d)\n",
+                               __func__,
+                               link->link_id.enum_id - ENUM_ID_1,
+                               hop,
+                               result,
+                               link->lttpr_mode);
 
        return result;
 }