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 #define BCM63XX_DEFAULT_PSI_SIZE        64
  39
  40 static struct bcm963xx_nvram nvram;
  41 static int mac_addr_used;
  42
  43 void __init bcm63xx_nvram_init(void *addr)
  44 {
  45         unsigned int check_len;
  46         u32 crc, expected_crc;
  47         u8 hcs_mac_addr[ETH_ALEN] = { 0x00, 0x10, 0x18, 0xff, 0xff, 0xff };
  48
  49         /* extract nvram data */
  50         memcpy(&nvram, addr, sizeof(nvram));
  51
  52         /* check checksum before using data */
  53         if (nvram.version <= 4) {
  54                 check_len = offsetof(struct bcm963xx_nvram, reserved3);
  55                 expected_crc = nvram.checksum_old;
  56                 nvram.checksum_old = 0;
  57         } else {
  58                 check_len = sizeof(nvram);
  59                 expected_crc = nvram.checksum_high;
  60                 nvram.checksum_high = 0;
  61         }
  62
  63         crc = crc32_le(~0, (u8 *)&nvram, check_len);
  64
  65         if (crc != expected_crc)
  66                 pr_warn("nvram checksum failed, contents may be invalid (expected %08x, got %08x)\n",
  67                         expected_crc, crc);
  68
  69         /* Cable modems have a different NVRAM which is embedded in the eCos
  70          * firmware and not easily extractible, give at least a MAC address
  71          * pool.
  72          */
  73         if (BCMCPU_IS_3368()) {
  74                 memcpy(nvram.mac_addr_base, hcs_mac_addr, ETH_ALEN);
  75                 nvram.mac_addr_count = 2;
  76         }
  77 }
  78
  79 u8 *bcm63xx_nvram_get_name(void)
  80 {
  81         return nvram.name;
  82 }
  83 EXPORT_SYMBOL(bcm63xx_nvram_get_name);
  84
  85 int bcm63xx_nvram_get_mac_address(u8 *mac)
  86 {
  87         u8 *oui;
  88         int count;
  89
  90         if (mac_addr_used >= nvram.mac_addr_count) {
  91                 pr_err("not enough mac addresses\n");
  92                 return -ENODEV;
  93         }
  94
  95         memcpy(mac, nvram.mac_addr_base, ETH_ALEN);
  96         oui = mac + ETH_ALEN/2 - 1;
  97         count = mac_addr_used;
  98
  99         while (count--) {
 100                 u8 *p = mac + ETH_ALEN - 1;
 101
 102                 do {
 103                         (*p)++;
 104                         if (*p != 0)
 105                                 break;
 106                         p--;
 107                 } while (p != oui);
 108
 109                 if (p == oui) {
 110                         pr_err("unable to fetch mac address\n");
 111                         return -ENODEV;
 112                 }
 113         }
 114
 115         mac_addr_used++;
 116         return 0;
 117 }
 118 EXPORT_SYMBOL(bcm63xx_nvram_get_mac_address);
 119
 120 int bcm63xx_nvram_get_psi_size(void)
 121 {
 122         if (nvram.psi_size > 0)
 123                 return nvram.psi_size;
 124
 125         return BCM63XX_DEFAULT_PSI_SIZE;
 126 }
 127 EXPORT_SYMBOL(bcm63xx_nvram_get_psi_size);