Diff: helpers.cpp

Revision:

0:176af1483f18

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/helpers.cpp	Mon Jul 29 20:38:08 2019 +0000
@@ -0,0 +1,73 @@
+#include "helpers.h"
+#include "QSPI_DISCO_F469NI.h" // internal storage
+
+static RNG_HandleTypeDef rng;
+
+// internal storage we will use to store mnemonic
+QSPI_DISCO_F469NI qspi;
+#define WRITE_READ_ADDR     ((uint32_t)0x0050)
+#define QSPI_BASE_ADDR      ((uint32_t)0x90000000)
+
+// magic constant to check if we saved the mnemonic already
+static const char magic[] = "mnemonic";
+
+GUI gui;
+
+void init(){
+    initRNG();
+    qspi.Init();
+    gui.init();
+}
+
+string loadMnemonic(){
+    char buffer[300] = "";
+    qspi.Read((uint8_t *)buffer, WRITE_READ_ADDR, sizeof(buffer)-1);
+    if(memcmp(magic, buffer, strlen(magic))!=0){
+        return "";
+    }
+    return buffer+strlen(magic);
+}
+
+int saveMnemonic(string mnemonic){
+    qspi.Erase_Block(WRITE_READ_ADDR);
+    qspi.Write((uint8_t *)magic, WRITE_READ_ADDR, strlen(magic));
+    qspi.Write((uint8_t *)mnemonic.c_str(), WRITE_READ_ADDR+strlen(magic), mnemonic.length()+1);
+    return 1;
+}
+
+int wipe(){
+    qspi.Erase_Block(WRITE_READ_ADDR);
+    NVIC_SystemReset(); // reset the board
+}
+
+/*********** random number generator ***********/
+
+int initRNG(){
+  __HAL_RCC_RNG_CLK_ENABLE();
+  rng.Instance = RNG;
+  if(HAL_RNG_Init(&rng) != HAL_OK){
+    return 0;
+  }
+  return 1;
+}
+
+uint32_t getRandomNumber(void){
+  uint32_t rnd = 0xff;
+  if(HAL_RNG_GenerateRandomNumber(&rng, &rnd) != HAL_OK){
+    return 0;
+  }
+  return rnd;
+}
+
+size_t getRandomBuffer(uint8_t * arr, size_t len){
+    for(unsigned int i=0; 4*i<len; i++){
+        uint32_t r = getRandomNumber();
+        if( i*4+1< len ){
+            memcpy(arr+i*4, &r, 4);
+        }else{
+            memcpy(arr+i*4, &r, len-i*4);
+        }
+    }
+    return len;
+}
+