target/linux/ar71xx/files/arch/mips/ar71xx/nvram.c

   1 /*
   2  *  Atheros AR71xx minimal nvram support
   3  *
   4  *  Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify it
   7  *  under the terms of the GNU General Public License version 2 as published
   8  *  by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/vmalloc.h>
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/string.h>
  16
  17 #include "nvram.h"
  18
  19 char *nvram_find_var(const char *name, const char *buf, unsigned buf_len)
  20 {
  21         unsigned len = strlen(name);
  22         char *cur, *last;
  23
  24         if (buf_len == 0 || len == 0)
  25                 return NULL;
  26
  27         if (buf_len < len)
  28                 return NULL;
  29
  30         if (len == 1)
  31                 return memchr(buf, (int) *name, buf_len);
  32
  33         last = (char *) buf + buf_len - len;
  34         for (cur = (char *) buf; cur <= last; cur++)
  35                 if (cur[0] == name[0] && memcmp(cur, name, len) == 0)
  36                         return cur + len;
  37
  38         return NULL;
  39 }
  40
  41 int nvram_parse_mac_addr(const char *nvram, unsigned nvram_len,
  42                          const char *name, char *mac)
  43 {
  44         char *buf;
  45         char *mac_str;
  46         int ret;
  47         int t;
  48
  49         buf = vmalloc(nvram_len);
  50         if (!buf)
  51                 return -ENOMEM;
  52
  53         memcpy(buf, nvram, nvram_len);
  54         buf[nvram_len - 1] = '\0';
  55
  56         mac_str = nvram_find_var(name, buf, nvram_len);
  57         if (!mac_str) {
  58                 ret = -EINVAL;
  59                 goto free;
  60         }
  61
  62         t = sscanf(mac_str, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
  63                    &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5]);
  64
  65         if (t != 6) {
  66                 ret = -EINVAL;
  67                 goto free;
  68         }
  69
  70         ret = 0;
  71
  72 free:
  73         vfree(buf);
  74         return ret;
  75 }