target/linux/brcm47xx/files-2.6.25/arch/mips/bcm47xx/nvram.c

   1 /*
   2  * BCM947xx nvram variable access
   3  *
   4  * Copyright 2005, Broadcom Corporation
   5  * Copyright 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/module.h>
  15 #include <linux/ssb/ssb.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/slab.h>
  21 #include <asm/byteorder.h>
  22 #include <asm/bootinfo.h>
  23 #include <asm/addrspace.h>
  24 #include <asm/io.h>
  25 #include <asm/uaccess.h>
  26
  27 #include <nvram.h>
  28
  29 #define MB * 1048576
  30 extern struct ssb_bus ssb;
  31
  32 static char nvram_buf[NVRAM_SPACE];
  33 static int cfe_env;
  34 extern char *cfe_env_get(char *nv_buf, const char *name);
  35
  36 /* Probe for NVRAM header */
  37 static void __init early_nvram_init(void)
  38 {
  39         struct ssb_mipscore *mcore = &ssb.mipscore;
  40         struct nvram_header *header;
  41         int i;
  42         u32 base, lim, off;
  43         u32 *src, *dst;
  44
  45         base = mcore->flash_window;
  46         lim = mcore->flash_window_size;
  47         cfe_env = 0;
  48
  49
  50         /* XXX: hack for supporting the CFE environment stuff on WGT634U */
  51         if (lim >= 8 MB) {
  52                 src = (u32 *) KSEG1ADDR(base + 8 MB - 0x2000);
  53                 dst = (u32 *) nvram_buf;
  54
  55                 if ((*src & 0xff00ff) == 0x000001) {
  56                         printk("early_nvram_init: WGT634U NVRAM found.\n");
  57
  58                         for (i = 0; i < 0x1ff0; i++) {
  59                                 if (*src == 0xFFFFFFFF)
  60                                         break;
  61                                 *dst++ = *src++;
  62                         }
  63                         cfe_env = 1;
  64                         return;
  65                 }
  66         }
  67
  68         off = 0x20000;
  69         while (off <= lim) {
  70                 /* Windowed flash access */
  71                 header = (struct nvram_header *) KSEG1ADDR(base + off - NVRAM_SPACE);
  72                 if (header->magic == NVRAM_HEADER)
  73                         goto found;
  74                 off <<= 1;
  75         }
  76
  77         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  78         header = (struct nvram_header *) KSEG1ADDR(base + 4096);
  79         if (header->magic == NVRAM_HEADER)
  80                 goto found;
  81
  82         header = (struct nvram_header *) KSEG1ADDR(base + 1024);
  83         if (header->magic == NVRAM_HEADER)
  84                 goto found;
  85
  86         return;
  87
  88 found:
  89         src = (u32 *) header;
  90         dst = (u32 *) nvram_buf;
  91         for (i = 0; i < sizeof(struct nvram_header); i += 4)
  92                 *dst++ = *src++;
  93         for (; i < header->len && i < NVRAM_SPACE; i += 4)
  94                 *dst++ = le32_to_cpu(*src++);
  95 }
  96
  97 char *nvram_get(const char *name)
  98 {
  99         char *var, *value, *end, *eq;
 100
 101         if (!name)
 102                 return NULL;
 103
 104         if (!nvram_buf[0])
 105                 early_nvram_init();
 106
 107         if (cfe_env)
 108                 return cfe_env_get(nvram_buf, name);
 109
 110         /* Look for name=value and return value */
 111         var = &nvram_buf[sizeof(struct nvram_header)];
 112         end = nvram_buf + sizeof(nvram_buf) - 2;
 113         end[0] = end[1] = '\0';
 114         for (; *var; var = value + strlen(value) + 1) {
 115                 if (!(eq = strchr(var, '=')))
 116                         break;
 117                 value = eq + 1;
 118                 if ((eq - var) == strlen(name) && strncmp(var, name, (eq - var)) == 0)
 119                         return value;
 120         }
 121
 122         return NULL;
 123 }
 124
 125 EXPORT_SYMBOL(nvram_get);