rse_comms: Fix pointer access protocol

Fix the RSE COMM files to properly calculate the size of the message
when the pointer access protocol is selected.

Signed-off-by: Michael Zhao <michael.zhao2@arm.com>
Change-Id: If7534198a884128fb5c5bbdc5e1a1c0bf77eba11
diff --git a/components/rpc/rse_comms/caller/sp/rse_comms_protocol.c b/components/rpc/rse_comms/caller/sp/rse_comms_protocol.c
index 7c2f476..64a0bcc 100644
--- a/components/rpc/rse_comms/caller/sp/rse_comms_protocol.c
+++ b/components/rpc/rse_comms/caller/sp/rse_comms_protocol.c
@@ -92,6 +92,10 @@
 
 		break;
 	case RSE_COMMS_PROTOCOL_POINTER_ACCESS:
+		status = rse_protocol_pointer_access_calculate_msg_len(handle, in_vec, in_len, msg_len);
+		if (status != PSA_SUCCESS)
+			return status;
+		break;
 	default:
 		return PSA_ERROR_NOT_SUPPORTED;
 	}
diff --git a/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.c b/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.c
index 1bbdc3d..b6f817c 100644
--- a/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.c
+++ b/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.c
@@ -61,3 +61,19 @@
 
 	return PSA_SUCCESS;
 }
+
+psa_status_t rse_protocol_pointer_access_calculate_msg_len(psa_handle_t handle,
+							   const struct psa_invec *in_vec,
+							   uint8_t in_len,
+							   size_t *msg_len)
+{
+	(void)handle;
+	(void)in_vec;
+	(void)in_len;
+
+	assert(msg_len != NULL);
+
+	*msg_len = sizeof(struct rse_pointer_access_msg_t);
+
+	return PSA_SUCCESS;
+}
diff --git a/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.h b/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.h
index 84845a9..5a59477 100644
--- a/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.h
+++ b/components/rpc/rse_comms/caller/sp/rse_comms_protocol_pointer_access.h
@@ -39,4 +39,9 @@
 							   const struct rse_pointer_access_reply_t *reply,
 							   size_t reply_size);
 
+psa_status_t rse_protocol_pointer_access_calculate_msg_len(psa_handle_t handle,
+							   const struct psa_invec *in_vec,
+							   uint8_t in_len,
+							   size_t *msg_len);
+
 #endif /* __RSE_COMMS_PROTOCOL_POINTER_ACCESS_H__ */