drm/amd/display: Add DSC granular throughput adjustment

[Why/How]
Update DSC DPCD parsing to take granular throughput adjustment into
consideration.
Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c

@@ -331,8 +331,9 @@ bool dc_dsc_parse_dsc_dpcd(const struct dc *dc,
 		int buff_block_size;
 		int buff_size;
 
-		if (!dsc_buff_block_size_from_dpcd(dpcd_dsc_basic_data[DP_DSC_RC_BUF_BLK_SIZE - DP_DSC_SUPPORT],
-										   &buff_block_size))
+		if (!dsc_buff_block_size_from_dpcd(
+				dpcd_dsc_basic_data[DP_DSC_RC_BUF_BLK_SIZE - DP_DSC_SUPPORT] & 0x03,
+				&buff_block_size))
 			return false;
 
 		buff_size = dpcd_dsc_basic_data[DP_DSC_RC_BUF_SIZE - DP_DSC_SUPPORT] + 1;
@@ -357,10 +358,15 @@ bool dc_dsc_parse_dsc_dpcd(const struct dc *dc,
 
 	{
 		int dpcd_throughput = dpcd_dsc_basic_data[DP_DSC_PEAK_THROUGHPUT - DP_DSC_SUPPORT];
+		int dsc_throughput_granular_delta;
+
+		dsc_throughput_granular_delta = dpcd_dsc_basic_data[DP_DSC_RC_BUF_BLK_SIZE - DP_DSC_SUPPORT] >> 3;
+		dsc_throughput_granular_delta *= 2;
 
 		if (!dsc_throughput_from_dpcd(dpcd_throughput & DP_DSC_THROUGHPUT_MODE_0_MASK,
 									  &dsc_sink_caps->throughput_mode_0_mps))
 			return false;
+		dsc_sink_caps->throughput_mode_0_mps += dsc_throughput_granular_delta;
 
 		dpcd_throughput = (dpcd_throughput & DP_DSC_THROUGHPUT_MODE_1_MASK) >> DP_DSC_THROUGHPUT_MODE_1_SHIFT;
 		if (!dsc_throughput_from_dpcd(dpcd_throughput, &dsc_sink_caps->throughput_mode_1_mps))