[PATCH 09/16] drm/amd/display: Read LTTPR ALPM caps during link cap retrieval

[Roman.Li]

From: George Shen <george.s...@amd.com>

[Why]
The latest DP spec requires the DP TX to read DPCD F0000h through F0009h
when detecting LTTPR capabilities for the first time.

[How]
Update LTTPR cap retrieval to read up to F0009h (two more bytes than the
previous F0007h), and store the LTTPR ALPM capabilities.

Reviewed-by: Wenjing Liu <wenjing....@amd.com>
Signed-off-by: George Shen <george.s...@amd.com>
Signed-off-by: Roman Li <roman...@amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_dp_types.h         | 12 ++++++++++++
 .../display/dc/link/protocols/link_dp_capability.c   |  6 +++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h 
b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
index 94ce8fe74481..ae6e2d8552ac 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -959,6 +959,14 @@ union dp_128b_132b_supported_lttpr_link_rates {
        uint8_t raw;
 };
 
+union dp_alpm_lttpr_cap {
+       struct {
+               uint8_t AUX_LESS_ALPM_SUPPORTED :1;
+               uint8_t RESERVED                                :7;
+       } bits;
+       uint8_t raw;
+};
+
 union dp_sink_video_fallback_formats {
        struct {
                uint8_t dp_1024x768_60Hz_24bpp_support  :1;
@@ -1118,6 +1126,7 @@ struct dc_lttpr_caps {
        uint8_t max_ext_timeout;
        union dp_main_link_channel_coding_lttpr_cap main_link_channel_coding;
        union dp_128b_132b_supported_lttpr_link_rates supported_128b_132b_rates;
+       union dp_alpm_lttpr_cap alpm;
        uint8_t aux_rd_interval[MAX_REPEATER_CNT - 1];
 };
 
@@ -1370,6 +1379,9 @@ struct dp_trace {
 #ifndef DPCD_MAX_UNCOMPRESSED_PIXEL_RATE_CAP
 #define DPCD_MAX_UNCOMPRESSED_PIXEL_RATE_CAP    0x221c
 #endif
+#ifndef DP_LTTPR_ALPM_CAPABILITIES
+#define DP_LTTPR_ALPM_CAPABILITIES              0xF0009
+#endif
 #ifndef DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE
 #define DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE      0x50
 #endif
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c 
b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index 44c3023a7731..80439224acca 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -1502,7 +1502,7 @@ static bool dpcd_read_sink_ext_caps(struct dc_link *link)
 
 enum dc_status dp_retrieve_lttpr_cap(struct dc_link *link)
 {
-       uint8_t lttpr_dpcd_data[8] = {0};
+       uint8_t lttpr_dpcd_data[10] = {0};
        enum dc_status status;
        bool is_lttpr_present;
 
@@ -1552,6 +1552,10 @@ enum dc_status dp_retrieve_lttpr_cap(struct dc_link 
*link)
                        lttpr_dpcd_data[DP_PHY_REPEATER_128B132B_RATES -
                                                        
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];
 
+       link->dpcd_caps.lttpr_caps.alpm.raw =
+                       lttpr_dpcd_data[DP_LTTPR_ALPM_CAPABILITIES -
+                                                       
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];
+
        /* If this chip cap is set, at least one retimer must exist in the chain
         * Override count to 1 if we receive a known bad count (0 or an invalid 
value) */
        if (((link->chip_caps & AMD_EXT_DISPLAY_PATH_CAPS__EXT_CHIP_MASK) == 
AMD_EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
-- 
2.34.1