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RIOT/cpu/stm32_common/periph/flashpage.c 2.81 KB
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  /*
   * Copyright (C) 2016 Freie Universitรคt Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     cpu_stm32_common
   * @ingroup     drivers_periph_flashpage
   * @{
   *
   * @file
   * @brief       Low-level flash page driver implementation
   *
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   *
   * @}
   */
  
  #include "cpu.h"
  #include "assert.h"
  
  #define ENABLE_DEBUG        (0)
  #include "debug.h"
  
  #if defined(FLASHPAGE_SIZE) && defined(FLASHPAGE_NUMOF)
  #include "periph/flashpage.h"
  
  void flashpage_write(int page, void *data)
  {
      assert(page < FLASHPAGE_NUMOF);
  
      uint16_t *page_addr = flashpage_addr(page);
      uint16_t *data_addr = (uint16_t *)data;
      uint32_t hsi_state = (RCC->CR & RCC_CR_HSION);
  
      /* the internal RC oscillator (HSI) must be enabled */
      RCC->CR |= (RCC_CR_HSION);
      while (!(RCC->CR & RCC_CR_HSIRDY)) {}
  
      /* unlock the flash module */
      DEBUG("[flashpage] unlocking the flash module\n");
      if (FLASH->CR & FLASH_CR_LOCK) {
          FLASH->KEYR = FLASH_KEY1;
          FLASH->KEYR = FLASH_KEY2;
      }
  
      /* ERASE sequence */
      /* make sure no flash operation is ongoing */
      DEBUG("[flashpage] erase: waiting for any operation to finish\n");
      while (FLASH->SR & FLASH_SR_BSY) {}
      /* set page erase bit and program page address */
      DEBUG("[flashpage] erase: setting the erase bit and page address\n");
      FLASH->CR |= FLASH_CR_PER;
      FLASH->AR = (uint32_t)flashpage_addr(page);
      DEBUG("address to erase: %p\n", flashpage_addr(page));
      /* trigger the page erase and wait for it to be finished */
      DEBUG("[flashpage] erase: trigger the page erase\n");
      FLASH->CR |= FLASH_CR_STRT;
      DEBUG("[flashpage] erase: wait as long as device is busy\n");
      while (FLASH->SR & FLASH_SR_BSY) {}
      /* reset PER bit */
      DEBUG("[flashpage] erase: resetting the page erase bit\n");
      FLASH->CR &= ~(FLASH_CR_PER);
  
      /* WRITE sequence */
      if (data != NULL) {
          DEBUG("[flashpage] write: now writing the data\n");
          /* set PG bit and program page to flash */
          FLASH->CR |= FLASH_CR_PG;
          for (unsigned i = 0; i < (FLASHPAGE_SIZE / 2); i++) {
              *page_addr++ = data_addr[i];
              while (FLASH->SR & FLASH_SR_BSY) {}
          }
          /* clear program bit again */
          FLASH->CR &= ~(FLASH_CR_PG);
          DEBUG("[flashpage] write: done writing data\n");
      }
  
      /* finally, lock the flash module again */
      DEBUG("flashpage] now locking the flash module again\n");
      FLASH->CR |= FLASH_CR_LOCK;
  
      /* restore the HSI state */
      if (!hsi_state) {
          RCC->CR &= ~(RCC_CR_HSION);
          while (RCC->CR & RCC_CR_HSIRDY) {}
      }
  }
  
  #endif /* defined(FLASHPAGE_SIZE) && defined(FLASHPAGE_NUMOF) */