Merge pull request arduino#338 from pennam/trng

Portenta C33 UNO R4 minima UNO R4 WiFi allow usage of TRNG

cores/arduino/WMath.cpp

@@ -23,10 +23,47 @@
 
 extern "C" {
   #include <stdlib.h>
+  #include "common_data.h"
 }
 
+#if defined (ARDUINO_PORTENTA_C33)
+#define SCE_TRNG_SUPPORT 1
+static long trng()
+{
+  uint32_t value[4];
+  if (R_SCE_Open(&sce_ctrl, &sce_cfg) != FSP_SUCCESS)
+    return -1;
+  R_SCE_RandomNumberGenerate(value);
+  R_SCE_Close(&sce_ctrl);
+  return (long)value[0] >= 0 ? value[0] : -value[0];
+}
+#endif
+
+#if defined(ARDUINO_UNOR4_WIFI) || defined(ARDUINO_UNOR4_MINIMA)
+#define SCE_TRNG_SUPPORT 1
+extern "C" {
+  fsp_err_t HW_SCE_McuSpecificInit(void);
+  fsp_err_t HW_SCE_RNG_Read(uint32_t * OutData_Text);
+}
+static long trng()
+{
+  uint32_t value[4];
+  if (HW_SCE_McuSpecificInit() != FSP_SUCCESS)
+    return -1;
+  HW_SCE_RNG_Read(value);
+  return (long)value[0] >= 0 ? value[0] : -value[0];
+}
+#endif
+
+#if (SCE_TRNG_SUPPORT == 1)
+static bool useTRNG = true;
+#endif
+
 void randomSeed(unsigned long seed)
 {
+#if (SCE_TRNG_SUPPORT == 1)
+  useTRNG = false;
+#endif
   if (seed != 0) {
     srand(seed);
   }
@@ -37,6 +74,11 @@ long random(long howbig)
   if (howbig == 0) {
     return 0;
   }
+#if (SCE_TRNG_SUPPORT == 1)
+  if (useTRNG == true) {
+    return trng() % howbig;
+  }
+#endif
   return rand() % howbig;
 }
 
@@ -48,3 +90,5 @@ long random(long howsmall, long howbig)
   long diff = howbig - howsmall;
   return random(diff) + howsmall;
 }
+
+#undef SCE_TRNG_SUPPORT