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) 2010-2012 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 <bcm47xx_nvram.h>
  22 #include <asm/mach-bcm47xx/bcm47xx.h>
  23
  24 static char nvram_buf[NVRAM_SPACE];
  25
  26 static u32 find_nvram_size(u32 end)
  27 {
  28         struct nvram_header *header;
  29         u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
  30         int i;
  31
  32         for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  33                 header = (struct nvram_header *)KSEG1ADDR(end - nvram_sizes[i]);
  34                 if (header->magic == NVRAM_HEADER)
  35                         return nvram_sizes[i];
  36         }
  37
  38         return 0;
  39 }
  40
  41 /* Probe for NVRAM header */
  42 static int nvram_find_and_copy(u32 base, u32 lim)
  43 {
  44         struct nvram_header *header;
  45         int i;
  46         u32 off;
  47         u32 *src, *dst;
  48         u32 size;
  49
  50         /* TODO: when nvram is on nand flash check for bad blocks first. */
  51         off = FLASH_MIN;
  52         while (off <= lim) {
  53                 /* Windowed flash access */
  54                 size = find_nvram_size(base + off);
  55                 if (size) {
  56                         header = (struct nvram_header *)KSEG1ADDR(base + off -
  57                                                                   size);
  58                         goto found;
  59                 }
  60                 off <<= 1;
  61         }
  62
  63         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  64         header = (struct nvram_header *) KSEG1ADDR(base + 4096);
  65         if (header->magic == NVRAM_HEADER) {
  66                 size = NVRAM_SPACE;
  67                 goto found;
  68         }
  69
  70         header = (struct nvram_header *) KSEG1ADDR(base + 1024);
  71         if (header->magic == NVRAM_HEADER) {
  72                 size = NVRAM_SPACE;
  73                 goto found;
  74         }
  75
  76         pr_err("no nvram found\n");
  77         return -ENXIO;
  78
  79 found:
  80
  81         if (header->len > size)
  82                 pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
  83         if (header->len > NVRAM_SPACE)
  84                 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
  85                        header->len, NVRAM_SPACE);
  86
  87         src = (u32 *) header;
  88         dst = (u32 *) nvram_buf;
  89         for (i = 0; i < sizeof(struct nvram_header); i += 4)
  90                 *dst++ = *src++;
  91         for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
  92                 *dst++ = le32_to_cpu(*src++);
  93         memset(dst, 0x0, NVRAM_SPACE - i);
  94
  95         return 0;
  96 }
  97
  98 #ifdef CONFIG_BCM47XX_SSB
  99 static int nvram_init_ssb(void)
 100 {
 101         struct ssb_mipscore *mcore = &bcm47xx_bus.ssb.mipscore;
 102         u32 base;
 103         u32 lim;
 104
 105         if (mcore->pflash.present) {
 106                 base = mcore->pflash.window;
 107                 lim = mcore->pflash.window_size;
 108         } else {
 109                 pr_err("Couldn't find supported flash memory\n");
 110                 return -ENXIO;
 111         }
 112
 113         return nvram_find_and_copy(base, lim);
 114 }
 115 #endif
 116
 117 #ifdef CONFIG_BCM47XX_BCMA
 118 static int nvram_init_bcma(void)
 119 {
 120         struct bcma_drv_cc *cc = &bcm47xx_bus.bcma.bus.drv_cc;
 121         u32 base;
 122         u32 lim;
 123
 124 #ifdef CONFIG_BCMA_NFLASH
 125         if (cc->nflash.boot) {
 126                 base = BCMA_SOC_FLASH1;
 127                 lim = BCMA_SOC_FLASH1_SZ;
 128         } else
 129 #endif
 130         if (cc->pflash.present) {
 131                 base = cc->pflash.window;
 132                 lim = cc->pflash.window_size;
 133 #ifdef CONFIG_BCMA_SFLASH
 134         } else if (cc->sflash.present) {
 135                 base = cc->sflash.window;
 136                 lim = cc->sflash.size;
 137 #endif
 138         } else {
 139                 pr_err("Couldn't find supported flash memory\n");
 140                 return -ENXIO;
 141         }
 142
 143         return nvram_find_and_copy(base, lim);
 144 }
 145 #endif
 146
 147 static int nvram_init(void)
 148 {
 149         switch (bcm47xx_bus_type) {
 150 #ifdef CONFIG_BCM47XX_SSB
 151         case BCM47XX_BUS_TYPE_SSB:
 152                 return nvram_init_ssb();
 153 #endif
 154 #ifdef CONFIG_BCM47XX_BCMA
 155         case BCM47XX_BUS_TYPE_BCMA:
 156                 return nvram_init_bcma();
 157 #endif
 158         }
 159         return -ENXIO;
 160 }
 161
 162 int bcm47xx_nvram_getenv(char *name, char *val, size_t val_len)
 163 {
 164         char *var, *value, *end, *eq;
 165         int err;
 166
 167         if (!name)
 168                 return -EINVAL;
 169
 170         if (!nvram_buf[0]) {
 171                 err = nvram_init();
 172                 if (err)
 173                         return err;
 174         }
 175
 176         /* Look for name=value and return value */
 177         var = &nvram_buf[sizeof(struct nvram_header)];
 178         end = nvram_buf + sizeof(nvram_buf) - 2;
 179         end[0] = end[1] = '\0';
 180         for (; *var; var = value + strlen(value) + 1) {
 181                 eq = strchr(var, '=');
 182                 if (!eq)
 183                         break;
 184                 value = eq + 1;
 185                 if ((eq - var) == strlen(name) &&
 186                         strncmp(var, name, (eq - var)) == 0) {
 187                         return snprintf(val, val_len, "%s", value);
 188                 }
 189         }
 190         return -ENOENT;
 191 }
 192 EXPORT_SYMBOL(bcm47xx_nvram_getenv);