WiFi: add arm_random functions if nanostack is not compiled in

Author: facchinm

Diff for: libraries/WiFi/src/utility/arm_hal_random.c

@@ -0,0 +1,40 @@
+#include "mbed_config.h"
+
+#if !defined(NS_USE_EXTERNAL_MBED_TLS)
+
+#include "ns_types.h"
+#include "arm_hal_random.h"
+
+#include "mbedtls/entropy_poll.h"
+
+#ifdef MBEDTLS_ENTROPY_HARDWARE_ALT
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#endif
+#endif
+
+void arm_random_module_init(void)
+{
+}
+
+uint32_t arm_random_seed_get(void)
+{
+    uint32_t result = 0;
+#ifdef MBEDTLS_ENTROPY_HARDWARE_ALT
+#if defined(MBEDTLS_PLATFORM_C)
+    int ret = mbedtls_platform_setup(NULL);
+    if (ret != 0) {
+        return result;
+    }
+#endif /* MBEDTLS_PLATFORM_C */
+    /* Grab a seed from a function we provide for mbedtls */
+    size_t len;
+    mbedtls_hardware_poll(NULL, (uint8_t *) &result, sizeof result, &len);
+#if defined(MBEDTLS_PLATFORM_C)
+    mbedtls_platform_teardown(NULL);
+#endif /* MBEDTLS_PLATFORM_C */
+#endif
+    return result;
+}
+
+#endif