eeprom.c

/*
 * Copyright (c) 2013, Robert Quattlebaum.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 *
 * Author: Robert Quattlebaum <darco@deepdarc.com>
 *
 */

#include "contiki.h"
#include "dev/eeprom.h"

#include <stdio.h>
#include <stdlib.h>

static FILE *eeprom_file;

/*---------------------------------------------------------------------------*/
static void
eeprom_fill(eeprom_addr_t addr, unsigned char value, int size)
{
  if((addr > EEPROM_END_ADDR) || (addr+size > EEPROM_END_ADDR+1) || size < 0) {
    fprintf(stderr, "eeprom_fill: Bad address and/or size (addr = %04x, size = %d)\n", addr, size);

    /* Abort here so that we break into the debugger. If a debugger isn't
     * attached, well we might as well crash anyway.
     */
    abort();
  }

  if(!eeprom_file) {
    eeprom_init();
  }

  fseek(eeprom_file, addr, SEEK_SET);

  while(size--) {
    if(fputc(value, eeprom_file) != value) {
      perror("fputc() failed");
      exit(EXIT_FAILURE);
    }
  }
}

/*---------------------------------------------------------------------------*/
void
eeprom_init(void)
{
  long length;
  char *eeprom_filename = getenv("CONTIKI_EEPROM");

  if(eeprom_filename) {
    eeprom_file = fopen(eeprom_filename, "r+");

    if(!eeprom_file) {
      /* File does exist yet, so let's create it. */
      eeprom_file = fopen(eeprom_filename, "w+");

      if(!eeprom_file) {
        perror("Unable to create EEPROM file");
        exit(EXIT_FAILURE);
      }
    }

    fprintf(stderr, "eeprom_init: Using \"%s\".\n", eeprom_filename);
  } else {
    eeprom_file = tmpfile();

    if(!eeprom_file) {
      perror("Unable to create temporary EEPROM file");
      exit(EXIT_FAILURE);
    }
  }

  /* Make sure that the file is the correct size by seeking
   * to the end and checking the file position. If it is
   * less than what we expect, we pad out the rest of the file
   * with 0xFF, just like a real EEPROM. */

  fseek(eeprom_file, 0, SEEK_END);
  length = ftell(eeprom_file);

  if(length < 0) {
    perror("ftell failed");
    exit(EXIT_FAILURE);
  }

  if(length < EEPROM_END_ADDR) {
    /* Fill with 0xFF, just like a real EEPROM. */
    eeprom_fill(length, 0xFF, EEPROM_SIZE - length);
  }
}

/*---------------------------------------------------------------------------*/
void
eeprom_write(eeprom_addr_t addr, unsigned char *buf, int size)
{
  if((addr > EEPROM_END_ADDR) || (addr+size > EEPROM_END_ADDR+1) || size < 0) {
    fprintf(stderr, "eeprom_write: Bad address and/or size (addr = %04x, size = %d)\n", addr, size);

    /* Abort here so that we break into the debugger. If a debugger isn't
     * attached, well we might as well crash anyway.
     */
    abort();
  }

  if(!eeprom_file) {
    eeprom_init();
  }

  fseek(eeprom_file, addr, SEEK_SET);

  if(fwrite(buf, 1, size, eeprom_file) != size) {
    perror("fwrite() failed");
    exit(EXIT_FAILURE);
  }
}

/*---------------------------------------------------------------------------*/
void
eeprom_read(eeprom_addr_t addr, unsigned char *buf, int size)
{
  if((addr > EEPROM_END_ADDR) || (addr+size > EEPROM_END_ADDR+1) || size < 0) {
    fprintf(stderr, "eeprom_read: Bad address and/or size (addr = %04x, size = %d)\n", addr, size);

    /* Abort here so that we break into the debugger. If a debugger isn't
     * attached, well we might as well crash anyway. */
    abort();
  }

  if(!eeprom_file) {
    eeprom_init();
  }

  fseek(eeprom_file, addr, SEEK_SET);

  if(fread(buf, 1, size, eeprom_file) != size) {
    perror("fread() failed");
    exit(EXIT_FAILURE);
  }
}