Merge pull request #9532 from kjbracey-arm/trng_mutex

Mutex-protect mbedtls_hardware_poll

Author: Cruz Monrreal

features/mbedtls/platform/src/mbed_trng.c renamed to features/mbedtls/platform/src/mbed_trng.cpp

@@ -17,12 +17,17 @@
 #if DEVICE_TRNG
 
 #include "hal/trng_api.h"
+#include "platform/PlatformMutex.h"
 
+extern "C"
 int mbedtls_hardware_poll( void *data, unsigned char *output, size_t len, size_t *olen ) {
+    static PlatformMutex trng_mutex;
     trng_t trng_obj;
+    trng_mutex.lock();
     trng_init(&trng_obj);
     int ret = trng_get_bytes(&trng_obj, output, len, olen);
     trng_free(&trng_obj);
+    trng_mutex.unlock();
     return ret;
 }