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 #ifdef CONFIG_BCM47XX_SSB
  30         struct ssb_mipscore *mcore_ssb;
  31 #endif
  32         struct nvram_header *header;
  33         int i;
  34         u32 base = 0;
  35         u32 lim = 0;
  36         u32 off;
  37         u32 *src, *dst;
  38
  39         switch (bcm47xx_bus_type) {
  40 #ifdef CONFIG_BCM47XX_SSB
  41         case BCM47XX_BUS_TYPE_SSB:
  42                 mcore_ssb = &bcm47xx_bus.ssb.mipscore;
  43                 base = mcore_ssb->flash_window;
  44                 lim = mcore_ssb->flash_window_size;
  45                 break;
  46 #endif
  47         }
  48
  49         off = FLASH_MIN;
  50         while (off <= lim) {
  51                 /* Windowed flash access */
  52                 header = (struct nvram_header *)
  53                         KSEG1ADDR(base + off - NVRAM_SPACE);
  54                 if (header->magic == NVRAM_HEADER)
  55                         goto found;
  56                 off <<= 1;
  57         }
  58
  59         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  60         header = (struct nvram_header *) KSEG1ADDR(base + 4096);
  61         if (header->magic == NVRAM_HEADER)
  62                 goto found;
  63
  64         header = (struct nvram_header *) KSEG1ADDR(base + 1024);
  65         if (header->magic == NVRAM_HEADER)
  66                 goto found;
  67
  68         return;
  69
  70 found:
  71         src = (u32 *) header;
  72         dst = (u32 *) nvram_buf;
  73         for (i = 0; i < sizeof(struct nvram_header); i += 4)
  74                 *dst++ = *src++;
  75         for (; i < header->len && i < NVRAM_SPACE; i += 4)
  76                 *dst++ = le32_to_cpu(*src++);
  77 }
  78
  79 int nvram_getenv(char *name, char *val, size_t val_len)
  80 {
  81         char *var, *value, *end, *eq;
  82
  83         if (!name)
  84                 return NVRAM_ERR_INV_PARAM;
  85
  86         if (!nvram_buf[0])
  87                 early_nvram_init();
  88
  89         /* Look for name=value and return value */
  90         var = &nvram_buf[sizeof(struct nvram_header)];
  91         end = nvram_buf + sizeof(nvram_buf) - 2;
  92         end[0] = end[1] = '\0';
  93         for (; *var; var = value + strlen(value) + 1) {
  94                 eq = strchr(var, '=');
  95                 if (!eq)
  96                         break;
  97                 value = eq + 1;
  98                 if ((eq - var) == strlen(name) &&
  99                         strncmp(var, name, (eq - var)) == 0) {
 100                         snprintf(val, val_len, "%s", value);
 101                         return 0;
 102                 }
 103         }
 104         return NVRAM_ERR_ENVNOTFOUND;
 105 }
 106 EXPORT_SYMBOL(nvram_getenv);