bootloader.c
#include "bootloader.h"
#include "protocol.h"
#include "stm32f30x_flash.h"
#include "usb_config.h"
#include <stdio.h>

uint8_t bl_wake = 0;
typedef volatile uint32_t vu32;
typedef uint32_t u32;
typedef void (*pFunction)(void);

static const WDGConfig wdgcfg = {STM32_IWDG_PR_64,
                                 STM32_IWDG_RL(500), // 500ms
                                 STM32_IWDG_WIN_DISABLED};

CCM_FUNC void startIWDG(void) { wdgStart(&WDGD1, &wdgcfg); }

extern volatile uint8_t reset_flags;
CCM_FUNC void startUserApp(void) {

  /* Setup IWDG in case the target application does not load */
  /* Disabled during debug */
  if ((reset_flags & FLAG_DBG) == 0) {
    startIWDG();
  } else {
    DEBUGEN(printf("IWDG Disabled for debug\n"));
  }

  chSysDisable();
  jumpToUser(USER_APP_ADDR);
}

CCM_FUNC void jumpToUser(uint32_t address) {

  pFunction Jump_To_Application;

  /* variable that will be loaded with the start address of the application */
  vu32 *JumpAddress;
  const vu32 *ApplicationAddress = (vu32 *)address;

  /* get jump address from application vector table */
  JumpAddress = (vu32 *)ApplicationAddress[1];

  /* load this address into function pointer */
  Jump_To_Application = (pFunction)JumpAddress;

  /* Clear pending interrupts just to be on the safe side*/
  SCB->ICSR = SCB_ICSR_PENDSVCLR_Msk;

  /* Disable all interrupts */
  uint8_t i;
  for (i = 0; i < 8; i++)
    NVIC->ICER[i] = NVIC->IABR[i];

  /* set stack pointer as in application's vector table */
  __set_MSP((u32)(ApplicationAddress[0]));
  Jump_To_Application();
}

CCM_FUNC uint8_t checkUserCode(uint32_t address) {

  const uint32_t sp = *(vu32 *)address;

  if ((sp & 0x2FFF0000) == 0x20000000     // SRAM
      || (sp & 0x1FFF0000) == 0x10000000) // CCM RAM
  {
    return 1;
  }
  return 0;
}

CCM_FUNC uint8_t eraseFlash(uint32_t len) {

  uint32_t addr;
  const uint32_t from = USER_APP_ADDR;
  const uint32_t to = from + len;

  if (len % 4) {
    return 1;
  }

  FLASH_Unlock();
  FLASH_ClearFlag(FLASH_FLAG_EOP | FLASH_FLAG_PGERR | FLASH_FLAG_WRPERR);

  for (addr = USER_APP_ADDR; addr <= to; addr += FLASH_PAGE_SIZE) {

    if (FLASH_ErasePage(addr) != FLASH_COMPLETE) {

      FLASH_Lock();
      return 1;
    }
  }

  FLASH_Lock();
  return 0;
}

CCM_FUNC uint8_t writeFlash(uint32_t addr, uint32_t *buf, uint8_t len) {

  uint8_t i;

  if (addr > 196 * 1024 || buf == NULL || !len) {

    return 1;
  }

  FLASH_Unlock();
  FLASH_ClearFlag(FLASH_FLAG_EOP | FLASH_FLAG_PGERR | FLASH_FLAG_WRPERR);

  for (i = 0; i < len; i++) {

    if (FLASH_ProgramWord(USER_APP_ADDR + addr + (i * 4), buf[i]) !=
        FLASH_COMPLETE) {

      FLASH_Lock();
      return 1;
    }
  }

  FLASH_Lock();
  return 0;
}