Test: Add integration of the eRPC system

 - PSA Client API IDL file
 - Client and server init and API wrappers
 - Example client application

Signed-off-by: Kevin Peng <kevin.peng@arm.com>
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
Signed-off-by: Summer Qin <summer.qin@arm.com>
Change-Id: If6180fd3e596c9daabd31262fb10ae0a1583bc9b
diff --git a/app/erpc_app.c b/app/erpc_app.c
new file mode 100644
index 0000000..af87f94
--- /dev/null
+++ b/app/erpc_app.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2017-2023, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include "test_app.h"
+#include "tfm_log.h"
+#include "erpc_server_start.h"
+#include "target_cfg.h"
+
+#include "Driver_USART.h"
+#ifdef ERPC_UART
+extern ARM_DRIVER_USART ERPC_UART;
+#else
+#error "ERPC_UART is not provided!"
+#endif
+
+__attribute__((noreturn))
+void test_app(void *argument)
+{
+    UNUSED_VARIABLE(argument);
+
+    erpc_transport_t transport;
+
+    transport = erpc_transport_cmsis_uart_init((void *)&ERPC_UART);
+    if (!transport) {
+        LOG_MSG("eRPC transport init failed!\r\n");
+    }
+
+    erpc_server_start(transport);
+
+    for (;;) {
+    }
+}