stmbl

/*
* This file is part of the stmbl project.
*
* Copyright (C) 2013-2015 Rene Hopf <renehopf@mac.com>
* Copyright (C) 2013-2015 Nico Stute <crinq@crinq.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "stm32f4xx_conf.h"
#include "version.h"

#if __GNUC__ < 5
   #error gcc to old (< 5.0)
#endif

#define APP_START 0x08010000
#define APP_END   0x08100000
#define APP_RANGE_VALID(a, s) (!(((a) | (s)) & 3) && (a) >= APP_START && ((a) + (s)) <= APP_END)
#define VERSION_INFO_OFFSET 0x188
static volatile const struct version_info *app_info = (void*)(APP_START + VERSION_INFO_OFFSET);

static int app_ok(void)
{
    if (!APP_RANGE_VALID(APP_START, app_info->image_size)) {
        return 0;
    }
    CRC_ResetDR();
    uint32_t crc = CRC_CalcBlockCRC((uint32_t *) APP_START, app_info->image_size / 4);

    if (crc != 0) {
        return 0;
    }

    return 1;
}

int main(void)
{
   GPIO_InitTypeDef GPIO_InitDef;
   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_CRC, ENABLE);
   GPIO_InitDef.GPIO_Pin = GPIO_Pin_13;
   GPIO_InitDef.GPIO_Mode = GPIO_Mode_IN;
   GPIO_InitDef.GPIO_OType = GPIO_OType_PP;
   GPIO_InitDef.GPIO_PuPd = GPIO_PuPd_UP;
   GPIO_InitDef.GPIO_Speed = GPIO_Speed_2MHz;
   GPIO_Init(GPIOA, &GPIO_InitDef);
   uint32_t pin = !GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_13);
   RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOA, ENABLE); // reset gpio a
   RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOA, DISABLE);
   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, DISABLE);

   void (*SysMemBootJump)(void);
   if ( (*((unsigned long *)0x2001C000) == 0xDEADBEEF) || pin || !app_ok()) {//Memory map, datasheet
      *((unsigned long *)0x2001C000) =  0xCAFEFEED; //Reset bootloader trigger
      __set_MSP(0x20001000);
      //Point the PC to the System Memory reset vector (+4)
      //AN2606
      //Table 64. Bootloader device-dependent parameters
      SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1FFF0004));
      SysMemBootJump();
      while (1);
   } else {
      uint32_t  stack = ((const uint32_t *) APP_START)[0];
      uint32_t  entry = ((const uint32_t *) APP_START)[1];
      asm volatile(
         "msr    msp, %0        \n\t"
         "bx     %1             \n\t"
         : : "r" (stack), "r" (entry)
      );
      while (1);
   }
}