[Intel-gfx] [PATCH v2 2/8] drm/dp: add 128b/132b link status helpers from DP 2.0 E11

Jani Nikula
2022-02-03T09:04:16Z

The DP 2.0 errata redefines link training. There are some new status
bits, and some of the old ones need to be checked independently. Add
helpers to do this.

Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
drivers/gpu/drm/dp/drm_dp.c | 63 ++++++++++++++++++++++++++++++++++
include/drm/dp/drm_dp_helper.h | 19 +++++++---
2 files changed, 77 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/dp/drm_dp.c b/drivers/gpu/drm/dp/drm_dp.c
index 52c6da510142..a20b0f8f24b8 100644
--- a/drivers/gpu/drm/dp/drm_dp.c
+++ b/drivers/gpu/drm/dp/drm_dp.c
@@ -144,6 +144,69 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE],
}
EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset);

+/* DP 2.0 errata for 128b/132b */
+bool drm_dp_128b132b_lane_channel_eq_done(const u8 link_status[DP_LINK_STATUS_SIZE],
+ int lane_count)
+{
+ u8 lane_align, lane_status;
+ int lane;
+
+ lane_align = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED);
+ if (!(lane_align & DP_INTERLANE_ALIGN_DONE))
+ return false;
+
+ for (lane = 0; lane < lane_count; lane++) {
+ lane_status = dp_get_lane_status(link_status, lane);
+ if (!(lane_status & DP_LANE_CHANNEL_EQ_DONE))
+ return false;
+ }
+ return true;
+}
+EXPORT_SYMBOL(drm_dp_128b132b_lane_channel_eq_done);
+
+/* DP 2.0 errata for 128b/132b */
+bool drm_dp_128b132b_lane_symbol_locked(const u8 link_status[DP_LINK_STATUS_SIZE],
+ int lane_count)
+{
+ u8 lane_status;
+ int lane;
+
+ for (lane = 0; lane < lane_count; lane++) {
+ lane_status = dp_get_lane_status(link_status, lane);
+ if (!(lane_status & DP_LANE_SYMBOL_LOCKED))
+ return false;
+ }
+ return true;
+}
+EXPORT_SYMBOL(drm_dp_128b132b_lane_symbol_locked);
+
+/* DP 2.0 errata for 128b/132b */
+bool drm_dp_128b132b_eq_interlane_align_done(const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+ u8 status = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED);
+
+ return status & DP_128B132B_DPRX_EQ_INTERLANE_ALIGN_DONE;
+}
+EXPORT_SYMBOL(drm_dp_128b132b_eq_interlane_align_done);
+
+/* DP 2.0 errata for 128b/132b */
+bool drm_dp_128b132b_cds_interlane_align_done(const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+ u8 status = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED);
+
+ return status & DP_128B132B_DPRX_CDS_INTERLANE_ALIGN_DONE;
+}
+EXPORT_SYMBOL(drm_dp_128b132b_cds_interlane_align_done);
+
+/* DP 2.0 errata for 128b/132b */
+bool drm_dp_128b132b_link_training_failed(const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+ u8 status = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED);
+
+ return status & DP_128B132B_LT_FAILED;
+}
+EXPORT_SYMBOL(drm_dp_128b132b_link_training_failed);
+
u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
unsigned int lane)
{
diff --git a/include/drm/dp/drm_dp_helper.h b/include/drm/dp/drm_dp_helper.h
index aa73dfc817ff..c499d735b992 100644
--- a/include/drm/dp/drm_dp_helper.h
+++ b/include/drm/dp/drm_dp_helper.h
@@ -738,11 +738,13 @@ struct drm_panel;
DP_LANE_CHANNEL_EQ_DONE | \
DP_LANE_SYMBOL_LOCKED)

-#define DP_LANE_ALIGN_STATUS_UPDATED 0x204
-
-#define DP_INTERLANE_ALIGN_DONE (1 << 0)
-#define DP_DOWNSTREAM_PORT_STATUS_CHANGED (1 << 6)
-#define DP_LINK_STATUS_UPDATED (1 << 7)
+#define DP_LANE_ALIGN_STATUS_UPDATED 0x204
+#define DP_INTERLANE_ALIGN_DONE (1 << 0)
+#define DP_128B132B_DPRX_EQ_INTERLANE_ALIGN_DONE (1 << 2) /* 2.0 E11 */
+#define DP_128B132B_DPRX_CDS_INTERLANE_ALIGN_DONE (1 << 3) /* 2.0 E11 */
+#define DP_128B132B_LT_FAILED (1 << 4) /* 2.0 E11 */
+#define DP_DOWNSTREAM_PORT_STATUS_CHANGED (1 << 6)
+#define DP_LINK_STATUS_UPDATED (1 << 7)

#define DP_SINK_STATUS 0x205
# define DP_RECEIVE_PORT_0_STATUS (1 << 0)
@@ -1551,6 +1553,13 @@ void drm_dp_lttpr_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);

int drm_dp_128b132b_read_aux_rd_interval(struct drm_dp_aux *aux);
+bool drm_dp_128b132b_lane_channel_eq_done(const u8 link_status[DP_LINK_STATUS_SIZE],
+ int lane_count);
+bool drm_dp_128b132b_lane_symbol_locked(const u8 link_status[DP_LINK_STATUS_SIZE],
+ int lane_count);
+bool drm_dp_128b132b_eq_interlane_align_done(const u8 link_status[DP_LINK_STATUS_SIZE]);
+bool drm_dp_128b132b_cds_interlane_align_done(const u8 link_status[DP_LINK_STATUS_SIZE]);
+bool drm_dp_128b132b_link_training_failed(const u8 link_status[DP_LINK_STATUS_SIZE]);

u8 drm_dp_link_rate_to_bw_code(int link_rate);
int drm_dp_bw_code_to_link_rate(u8 link_bw);
--
2.30.2