drm/amd/display: parse and check PSR SU caps

[why]
Adding a function to read PSR capabilities
and ALPM capabilities.
Also adding a helper function to validate if
the sink and the driver support PSR SU.
[how]
- isolated all PSR and ALPM reading calls to a separate funciton
- set all required PSR caps
- added a helper function to check if PSR SU is supported by sink
and the driver

Reviewed-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c

@@ -26,6 +26,73 @@
 #include "amdgpu_dm_psr.h"
 #include "dc.h"
 #include "dm_helpers.h"
+#include "amdgpu_dm.h"
+
+static bool link_get_psr_caps(struct dc_link *link)
+{
+	uint8_t psr_dpcd_data[EDP_PSR_RECEIVER_CAP_SIZE];
+	uint8_t edp_rev_dpcd_data;
+
+
+
+	if (!dm_helpers_dp_read_dpcd(NULL, link, DP_PSR_SUPPORT,
+				    psr_dpcd_data, sizeof(psr_dpcd_data)))
+		return false;
+
+	if (!dm_helpers_dp_read_dpcd(NULL, link, DP_EDP_DPCD_REV,
+				    &edp_rev_dpcd_data, sizeof(edp_rev_dpcd_data)))
+		return false;
+
+	link->dpcd_caps.psr_caps.psr_version = psr_dpcd_data[0];
+	link->dpcd_caps.psr_caps.edp_revision = edp_rev_dpcd_data;
+
+#ifdef CONFIG_DRM_AMD_DC_DCN
+	if (link->dpcd_caps.psr_caps.psr_version > 0x1) {
+		uint8_t alpm_dpcd_data;
+		uint8_t su_granularity_dpcd_data;
+
+		if (!dm_helpers_dp_read_dpcd(NULL, link, DP_RECEIVER_ALPM_CAP,
+						&alpm_dpcd_data, sizeof(alpm_dpcd_data)))
+			return false;
+
+		if (!dm_helpers_dp_read_dpcd(NULL, link, DP_PSR2_SU_Y_GRANULARITY,
+						&su_granularity_dpcd_data, sizeof(su_granularity_dpcd_data)))
+			return false;
+
+		link->dpcd_caps.psr_caps.y_coordinate_required = psr_dpcd_data[1] & DP_PSR2_SU_Y_COORDINATE_REQUIRED;
+		link->dpcd_caps.psr_caps.su_granularity_required = psr_dpcd_data[1] & DP_PSR2_SU_GRANULARITY_REQUIRED;
+
+		link->dpcd_caps.psr_caps.alpm_cap = alpm_dpcd_data & DP_ALPM_CAP;
+		link->dpcd_caps.psr_caps.standby_support = alpm_dpcd_data & (1 << 1);
+
+		link->dpcd_caps.psr_caps.su_y_granularity = su_granularity_dpcd_data;
+	}
+#endif
+	return true;
+}
+
+#ifdef CONFIG_DRM_AMD_DC_DCN
+static bool link_supports_psrsu(struct dc_link *link)
+{
+	struct dc *dc = link->ctx->dc;
+
+	if (!dc->caps.dmcub_support)
+		return false;
+
+	if (dc->ctx->dce_version < DCN_VERSION_3_1)
+		return false;
+
+	if (!link->dpcd_caps.psr_caps.alpm_cap ||
+	    !link->dpcd_caps.psr_caps.y_coordinate_required)
+		return false;
+
+	if (link->dpcd_caps.psr_caps.su_granularity_required &&
+	    !link->dpcd_caps.psr_caps.su_y_granularity)
+		return false;
+
+	return true;
+}
+#endif
 
 /*
  * amdgpu_dm_set_psr_caps() - set link psr capabilities
@@ -34,26 +101,34 @@
  */
 void amdgpu_dm_set_psr_caps(struct dc_link *link)
 {
-	uint8_t dpcd_data[EDP_PSR_RECEIVER_CAP_SIZE];
-
 	if (!(link->connector_signal & SIGNAL_TYPE_EDP))
 		return;
+
 	if (link->type == dc_connection_none)
 		return;
-	if (dm_helpers_dp_read_dpcd(NULL, link, DP_PSR_SUPPORT,
-					dpcd_data, sizeof(dpcd_data))) {
-		link->dpcd_caps.psr_caps.psr_version = dpcd_data[0];
 
-		if (dpcd_data[0] == 0) {
+	if (!link_get_psr_caps(link)) {
-			link->psr_settings.psr_version = DC_PSR_VERSION_UNSUPPORTED;
+		DRM_ERROR("amdgpu: Failed to read PSR Caps!\n");
-			link->psr_settings.psr_feature_enabled = false;
+		return;
-		} else {
-			link->psr_settings.psr_version = DC_PSR_VERSION_1;
-			link->psr_settings.psr_feature_enabled = true;
-		}
-
-		DRM_INFO("PSR support:%d\n", link->psr_settings.psr_feature_enabled);
 	}
+
+	if (link->dpcd_caps.psr_caps.psr_version == 0) {
+		link->psr_settings.psr_version = DC_PSR_VERSION_UNSUPPORTED;
+		link->psr_settings.psr_feature_enabled = false;
+
+	} else {
+#ifdef CONFIG_DRM_AMD_DC_DCN
+		if (link_supports_psrsu(link))
+			link->psr_settings.psr_version = DC_PSR_VERSION_SU_1;
+		else
+#endif
+			link->psr_settings.psr_version = DC_PSR_VERSION_1;
+
+		link->psr_settings.psr_feature_enabled = true;
+	}
+
+	DRM_INFO("PSR support:%d\n", link->psr_settings.psr_feature_enabled);
+
 }
 
 /*

drivers/gpu/drm/amd/display/dc/dc_dp_types.h

@@ -883,6 +883,15 @@ struct psr_caps {
 	unsigned char psr_version;
 	unsigned int psr_rfb_setup_time;
 	bool psr_exit_link_training_required;
+	unsigned char edp_revision;
+	unsigned char support_ver;
+	bool su_granularity_required;
+	bool y_coordinate_required;
+	uint8_t su_y_granularity;
+	bool alpm_cap;
+	bool standby_support;
+	uint8_t rate_control_caps;
+	unsigned int psr_power_opt_flag;
 };
 
 /* Length of router topology ID read from DPCD in bytes. */

drivers/gpu/drm/amd/display/dc/dc_types.h

@@ -951,6 +951,7 @@ enum dc_gpu_mem_alloc_type {
 
 enum dc_psr_version {
 	DC_PSR_VERSION_1			= 0,
+	DC_PSR_VERSION_SU_1			= 1,
 	DC_PSR_VERSION_UNSUPPORTED		= 0xFFFFFFFF,
 };