arch/mips/bcm47xx/nvram.c

   1 /*
   2  * BCM947xx nvram variable access
   3  *
   4  * Copyright (C) 2005 Broadcom Corporation
   5  * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
   6  * Copyright (C) 2010-2011 Hauke Mehrtens <hauke@hauke-m.de>
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/module.h>
  17 #include <linux/ssb/ssb.h>
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <asm/addrspace.h>
  21 #include <asm/mach-bcm47xx/nvram.h>
  22 #include <asm/mach-bcm47xx/bcm47xx.h>
  23
  24 static char nvram_buf[NVRAM_SPACE];
  25
  26 /* Probe for NVRAM header */
  27 static void early_nvram_init(void)
  28 {
  29         struct ssb_mipscore *mcore = &ssb_bcm47xx.mipscore;
  30         struct nvram_header *header;
  31         int i;
  32         u32 base, lim, off;
  33         u32 *src, *dst;
  34
  35         base = mcore->flash_window;
  36         lim = mcore->flash_window_size;
  37
  38         off = FLASH_MIN;
  39         while (off <= lim) {
  40                 /* Windowed flash access */
  41                 header = (struct nvram_header *)
  42                         KSEG1ADDR(base + off - NVRAM_SPACE);
  43                 if (header->magic == NVRAM_HEADER)
  44                         goto found;
  45                 off <<= 1;
  46         }
  47
  48         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  49         header = (struct nvram_header *) KSEG1ADDR(base + 4096);
  50         if (header->magic == NVRAM_HEADER)
  51                 goto found;
  52
  53         header = (struct nvram_header *) KSEG1ADDR(base + 1024);
  54         if (header->magic == NVRAM_HEADER)
  55                 goto found;
  56
  57         return;
  58
  59 found:
  60         src = (u32 *) header;
  61         dst = (u32 *) nvram_buf;
  62         for (i = 0; i < sizeof(struct nvram_header); i += 4)
  63                 *dst++ = *src++;
  64         for (; i < header->len && i < NVRAM_SPACE; i += 4)
  65                 *dst++ = le32_to_cpu(*src++);
  66 }
  67
  68 int nvram_getenv(char *name, char *val, size_t val_len)
  69 {
  70         char *var, *value, *end, *eq;
  71
  72         if (!name)
  73                 return NVRAM_ERR_INV_PARAM;
  74
  75         if (!nvram_buf[0])
  76                 early_nvram_init();
  77
  78         /* Look for name=value and return value */
  79         var = &nvram_buf[sizeof(struct nvram_header)];
  80         end = nvram_buf + sizeof(nvram_buf) - 2;
  81         end[0] = end[1] = '\0';
  82         for (; *var; var = value + strlen(value) + 1) {
  83                 eq = strchr(var, '=');
  84                 if (!eq)
  85                         break;
  86                 value = eq + 1;
  87                 if ((eq - var) == strlen(name) &&
  88                         strncmp(var, name, (eq - var)) == 0) {
  89                         snprintf(val, val_len, "%s", value);
  90                         return 0;
  91                 }
  92         }
  93         return NVRAM_ERR_ENVNOTFOUND;
  94 }
  95 EXPORT_SYMBOL(nvram_getenv);