drm/amd/display: Add support for runtime feature detection command

[Why]
Add support for new fw command for runtime feature detection.

[How]
Driver sends command through ring buffer, and fw returns data back
through this command.

Signed-off-by: Wyatt Wood <wyatt.wood@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dmub/dmub_srv.h

@@ -345,6 +345,9 @@ struct dmub_srv {
 	uint64_t fb_base;
 	uint64_t fb_offset;
 	uint32_t psp_version;
+
+	/* Feature capabilities reported by fw */
+	struct dmub_feature_caps feature_caps;
 };
 
 /**
@@ -608,6 +611,9 @@ void dmub_flush_buffer_mem(const struct dmub_fb *fb);
 enum dmub_status dmub_srv_get_fw_boot_status(struct dmub_srv *dmub,
 					     union dmub_fw_boot_status *status);
 
+enum dmub_status dmub_srv_cmd_with_reply_data(struct dmub_srv *dmub,
+					      union dmub_rb_cmd *cmd);
+
 #if defined(__cplusplus)
 }
 #endif

drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c

@@ -648,3 +648,32 @@ enum dmub_status dmub_srv_get_fw_boot_status(struct dmub_srv *dmub,
 
 	return DMUB_STATUS_OK;
 }
+
+enum dmub_status dmub_srv_cmd_with_reply_data(struct dmub_srv *dmub,
+					      union dmub_rb_cmd *cmd)
+{
+	enum dmub_status status = DMUB_STATUS_OK;
+
+	// Queue command
+	status = dmub_srv_cmd_queue(dmub, cmd);
+
+	if (status != DMUB_STATUS_OK)
+		return status;
+
+	// Execute command
+	status = dmub_srv_cmd_execute(dmub);
+
+	if (status != DMUB_STATUS_OK)
+		return status;
+
+	// Wait for DMUB to process command
+	status = dmub_srv_wait_for_idle(dmub, 100000);
+
+	if (status != DMUB_STATUS_OK)
+		return status;
+
+	// Copy data back from ring buffer into command
+	dmub_rb_get_return_data(&dmub->inbox1_rb, cmd);
+
+	return status;
+}