arch/mips/bcm63xx/nvram.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
   7  * Copyright (C) 2008 Florian Fainelli <florian@openwrt.org>
   8  * Copyright (C) 2012 Jonas Gorski <jonas.gorski@gmail.com>
   9  */
  10
  11 #define pr_fmt(fmt) "bcm63xx_nvram: " fmt
  12
  13 #include <linux/init.h>
  14 #include <linux/crc32.h>
  15 #include <linux/export.h>
  16 #include <linux/kernel.h>
  17 #include <linux/if_ether.h>
  18
  19 #include <bcm63xx_nvram.h>
  20
  21 /*
  22  * nvram structure
  23  */
  24 struct bcm963xx_nvram {
  25         u32     version;
  26         u8      reserved1[256];
  27         u8      name[16];
  28         u32     main_tp_number;
  29         u32     psi_size;
  30         u32     mac_addr_count;
  31         u8      mac_addr_base[ETH_ALEN];
  32         u8      reserved2[2];
  33         u32     checksum_old;
  34         u8      reserved3[720];
  35         u32     checksum_high;
  36 };
  37
  38 static struct bcm963xx_nvram nvram;
  39 static int mac_addr_used;
  40
  41 int __init bcm63xx_nvram_init(void *addr)
  42 {
  43         unsigned int check_len;
  44         u32 crc, expected_crc;
  45
  46         /* extract nvram data */
  47         memcpy(&nvram, addr, sizeof(nvram));
  48
  49         /* check checksum before using data */
  50         if (nvram.version <= 4) {
  51                 check_len = offsetof(struct bcm963xx_nvram, reserved3);
  52                 expected_crc = nvram.checksum_old;
  53                 nvram.checksum_old = 0;
  54         } else {
  55                 check_len = sizeof(nvram);
  56                 expected_crc = nvram.checksum_high;
  57                 nvram.checksum_high = 0;
  58         }
  59
  60         crc = crc32_le(~0, (u8 *)&nvram, check_len);
  61
  62         if (crc != expected_crc)
  63                 return -EINVAL;
  64
  65         return 0;
  66 }
  67
  68 u8 *bcm63xx_nvram_get_name(void)
  69 {
  70         return nvram.name;
  71 }
  72 EXPORT_SYMBOL(bcm63xx_nvram_get_name);
  73
  74 int bcm63xx_nvram_get_mac_address(u8 *mac)
  75 {
  76         u8 *oui;
  77         int count;
  78
  79         if (mac_addr_used >= nvram.mac_addr_count) {
  80                 pr_err("not enough mac addresses\n");
  81                 return -ENODEV;
  82         }
  83
  84         memcpy(mac, nvram.mac_addr_base, ETH_ALEN);
  85         oui = mac + ETH_ALEN/2 - 1;
  86         count = mac_addr_used;
  87
  88         while (count--) {
  89                 u8 *p = mac + ETH_ALEN - 1;
  90
  91                 do {
  92                         (*p)++;
  93                         if (*p != 0)
  94                                 break;
  95                         p--;
  96                 } while (p != oui);
  97
  98                 if (p == oui) {
  99                         pr_err("unable to fetch mac address\n");
 100                         return -ENODEV;
 101                 }
 102         }
 103
 104         mac_addr_used++;
 105         return 0;
 106 }
 107 EXPORT_SYMBOL(bcm63xx_nvram_get_mac_address);