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