[PATCH 04/28] drm/amd/display: Parse RECEIVE_PORT0_CAP capabilities from DPCD

[Roman.Li at amd.com]

From: George Shen <george.shen at amd.com>

[Why]
DPCD register RECEIVE_PORT0_CAP contains HBlank expansion/reduction
capabilities of a DP device. These capabilities are required to enable
HBlank expansion/reduction logic.

[How]
Read raw RECEIVE_PORT0_CAP register values and store parsed fields.

Reviewed-by: Wenjing Liu <wenjing.liu at amd.com>
Signed-off-by: George Shen <george.shen at amd.com>
Signed-off-by: Roman Li <roman.li at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc.h              |  8 ++++++++
 drivers/gpu/drm/amd/display/dc/dc_dp_types.h     | 16 ++++++++++++++++
 drivers/gpu/drm/amd/display/dc/dc_types.h        |  8 ++++++++
 .../dc/link/protocols/link_dp_capability.c       |  5 +++++
 4 files changed, 37 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index cccffffaf768..01f22706d27c 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -2383,6 +2383,13 @@ struct dc_sink_dsc_caps {
 	struct dsc_dec_dpcd_caps dsc_dec_caps;
 };
 
+struct dc_sink_hblank_expansion_caps {
+	// 'true' if these are virtual DPCD's HBlank expansion caps (immediately upstream of sink in MST topology),
+	// 'false' if they are sink's HBlank expansion caps
+	bool is_virtual_dpcd_hblank_expansion;
+	struct hblank_expansion_dpcd_caps dpcd_caps;
+};
+
 struct dc_sink_fec_caps {
 	bool is_rx_fec_supported;
 	bool is_topology_fec_supported;
@@ -2409,6 +2416,7 @@ struct dc_sink {
 	struct scdc_caps scdc_caps;
 	struct dc_sink_dsc_caps dsc_caps;
 	struct dc_sink_fec_caps fec_caps;
+	struct dc_sink_hblank_expansion_caps hblank_expansion_caps;
 
 	bool is_vsc_sdp_colorimetry_supported;
 
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 8dd6eb044829..94ce8fe74481 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -969,6 +969,21 @@ union dp_sink_video_fallback_formats {
 	uint8_t raw;
 };
 
+union dp_receive_port0_cap {
+	struct {
+		uint8_t RESERVED					:1;
+		uint8_t LOCAL_EDID_PRESENT			:1;
+		uint8_t ASSOCIATED_TO_PRECEDING_PORT:1;
+		uint8_t HBLANK_EXPANSION_CAPABLE	:1;
+		uint8_t BUFFER_SIZE_UNIT			:1;
+		uint8_t BUFFER_SIZE_PER_PORT		:1;
+		uint8_t HBLANK_REDUCTION_CAPABLE	:1;
+		uint8_t RESERVED2:1;
+		uint8_t BUFFER_SIZE:8;
+	} bits;
+	uint8_t raw[2];
+};
+
 union dpcd_max_uncompressed_pixel_rate_cap {
 	struct {
 		uint16_t max_uncompressed_pixel_rate_cap	:15;
@@ -1193,6 +1208,7 @@ struct dpcd_caps {
 
 	struct replay_info pr_info;
 	uint16_t edp_oled_emission_rate;
+	union dp_receive_port0_cap receive_port0_cap;
 };
 
 union dpcd_sink_ext_caps {
diff --git a/drivers/gpu/drm/amd/display/dc/dc_types.h b/drivers/gpu/drm/amd/display/dc/dc_types.h
index edf4df1d03b5..2792ef448d01 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_types.h
@@ -875,6 +875,14 @@ struct dsc_dec_dpcd_caps {
 	bool is_dp; /* Decoded format */
 };
 
+struct hblank_expansion_dpcd_caps {
+	bool expansion_supported;
+	bool reduction_supported;
+	bool buffer_unit_bytes; /* True: buffer size in bytes. False: buffer size in pixels*/
+	bool buffer_per_port; /* True: buffer size per port. False: buffer size per lane*/
+	uint32_t buffer_size; /* Add 1 to value and multiply by 32 */
+};
+
 struct dc_golden_table {
 	uint16_t dc_golden_table_ver;
 	uint32_t aux_dphy_rx_control0_val;
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 ce9d799d2386..d1d869cc85c7 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
@@ -1779,6 +1779,11 @@ static bool retrieve_link_cap(struct dc_link *link)
 	link->test_pattern_enabled = false;
 	link->compliance_test_state.raw = 0;
 
+	link->dpcd_caps.receive_port0_cap.raw[0] =
+			dpcd_data[DP_RECEIVE_PORT_0_CAP_0 - DP_DPCD_REV];
+	link->dpcd_caps.receive_port0_cap.raw[1] =
+			dpcd_data[DP_RECEIVE_PORT_0_BUFFER_SIZE - DP_DPCD_REV];
+
 	/* read sink count */
 	core_link_read_dpcd(link,
 			DP_SINK_COUNT,
-- 
2.34.1