Merge pull request #3154 from fdlamotte/nrf52_hwcrypto_init

nrf52: call nRFCrypto.begin()/end() only once

src/helpers/NRF52Board.cpp

@@ -5,6 +5,10 @@
 #include <bluefruit.h>
 #include <nrf_soc.h>
 
+#ifdef USE_CC310_HW_CRYPTO
+#include <Adafruit_nRFCrypto.h>
+#endif
+
 static BLEDfu bledfu;
 
 static void connect_callback(uint16_t conn_handle) {
@@ -21,6 +25,11 @@ static void disconnect_callback(uint16_t conn_handle, uint8_t reason) {
 
 void NRF52Board::begin() {
   startup_reason = BD_STARTUP_NORMAL;
+
+  #ifdef USE_CC310_HW_CRYPTO
+    // CC310 TRNG is higher quality and environment-independent vs radio RSSI noise.
+    nRFCrypto.begin();
+  #endif
 }
 
 #ifdef NRF52_POWER_MANAGEMENT
@@ -352,6 +361,10 @@ void NRF52Board::shutdownPeripherals() {
     sensors.getLocationProvider()->stop();
   }
 
+#ifdef USE_CC310_HW_CRYPTO
+    nRFCrypto.end();
+#endif
+
   // Flush serial buffers
   Serial.flush();
   delay(100);

src/helpers/radiolib/RadioLibWrappers.h

@@ -93,9 +93,7 @@ public:
   void random(uint8_t* dest, size_t sz) override {
 #ifdef USE_CC310_HW_CRYPTO
     // CC310 TRNG is higher quality and environment-independent vs radio RSSI noise.
-    nRFCrypto.begin();
     nRFCrypto.Random.generate(dest, (uint16_t)sz);
-    nRFCrypto.end();
 #else
     for (int i = 0; i < sz; i++) {
       dest[i] = _radio->randomByte() ^ (::random(0, 256) & 0xFF);