scmi_power_domain: Add error handling for failed set_state

This patch addresses an issue that will handle returning an SCMI
if the set_state request has failed and the power domain is in
sync mode. If the state request passes the initial sanity checking,
the response will be handled correctly. However if this is not
the case, it would return to the SCMI PD and never respond.

Signed-off-by: Katherine Vincent <katherine.vincent@arm.com>
Change-Id: Ic72992b052bda107c8d0719059d38e8d0491b8f8

module/scmi_power_domain/src/mod_scmi_power_domain.c

@@ -1,6 +1,6 @@
 /*
  * Arm SCP/MCP Software
- * Copyright (c) 2015-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -1178,18 +1178,19 @@ static int scmi_pd_process_bind_request(fwk_id_t source_id, fwk_id_t target_id,
 static int process_request_event(const struct fwk_event *event)
 {
     fwk_id_t pd_id;
+    int status;
+    int respond_status;
 #ifdef BUILD_HAS_MOD_DEBUG
     bool dbg_enabled;
-    fwk_id_t service_id;
-    int status, respond_status;
     bool state_get;
     struct scmi_pd_power_state_get_p2a retval_get = {
         .status = SCMI_GENERIC_ERROR
     };
+#endif
+    fwk_id_t service_id;
     struct scmi_pd_power_state_set_p2a retval_set = {
-        .status = SCMI_GENERIC_ERROR
+        .status = (int32_t)SCMI_GENERIC_ERROR
     };
-#endif
     struct event_request_params *params =
         (struct event_request_params *)event->params;
 
@@ -1228,8 +1229,23 @@ static int process_request_event(const struct fwk_event *event)
         break;
 #endif
     case SCMI_PD_EVENT_IDX_SET_STATE:
-        return scmi_pd_ctx.pd_api->set_state(
-            pd_id, true, params->pd_power_state);
+        status =
+            scmi_pd_ctx.pd_api->set_state(pd_id, true, params->pd_power_state);
+
+        if (status != FWK_SUCCESS) {
+            /* There was an error, so send the SCMI response to note this.*/
+            retval_set.status = (int32_t)SCMI_GENERIC_ERROR;
+            service_id = ops_get_service(pd_id);
+            respond_status = scmi_pd_ctx.scmi_api->respond(
+                service_id, &retval_set, sizeof(retval_set.status));
+
+            if (respond_status != FWK_SUCCESS) {
+                FWK_LOG_DEBUG("[SCMI-power] %s @%d", __func__, __LINE__);
+                return respond_status;
+            }
+        }
+
+        return status;
 
     default:
         return FWK_E_PARAM;