target/linux/bcm53xx/files/drivers/firmware/broadcom/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/io.h>
  15 #include <linux/types.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/mtd/mtd.h>
  20 #include <linux/bcm47xx_nvram.h>
  21
  22 #define NVRAM_MAGIC                     0x48534C46      /* 'FLSH' */
  23 #define NVRAM_SPACE                     0x10000
  24 #define NVRAM_MAX_GPIO_ENTRIES          32
  25 #define NVRAM_MAX_GPIO_VALUE_LEN        30
  26
  27 #define FLASH_MIN               0x00020000      /* Minimum flash size */
  28
  29 struct nvram_header {
  30         u32 magic;
  31         u32 len;
  32         u32 crc_ver_init;       /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
  33         u32 config_refresh;     /* 0:15 sdram_config, 16:31 sdram_refresh */
  34         u32 config_ncdl;        /* ncdl values for memc */
  35 };
  36
  37 static char nvram_buf[NVRAM_SPACE];
  38 static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
  39
  40 static u32 find_nvram_size(void __iomem *end)
  41 {
  42         struct nvram_header __iomem *header;
  43         int i;
  44
  45         for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  46                 header = (struct nvram_header *)(end - nvram_sizes[i]);
  47                 if (header->magic == NVRAM_MAGIC)
  48                         return nvram_sizes[i];
  49         }
  50
  51         return 0;
  52 }
  53
  54 /* Probe for NVRAM header */
  55 static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
  56 {
  57         struct nvram_header __iomem *header;
  58         int i;
  59         u32 off;
  60         u32 *src, *dst;
  61         u32 size;
  62
  63         if (nvram_buf[0]) {
  64                 pr_warn("nvram already initialized\n");
  65                 return -EEXIST;
  66         }
  67
  68         /* TODO: when nvram is on nand flash check for bad blocks first. */
  69         off = FLASH_MIN;
  70         while (off <= lim) {
  71                 /* Windowed flash access */
  72                 size = find_nvram_size(iobase + off);
  73                 if (size) {
  74                         header = (struct nvram_header *)(iobase + off - size);
  75                         goto found;
  76                 }
  77                 off <<= 1;
  78         }
  79
  80         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  81         header = (struct nvram_header *)(iobase + 4096);
  82         if (header->magic == NVRAM_MAGIC) {
  83                 size = NVRAM_SPACE;
  84                 goto found;
  85         }
  86
  87         header = (struct nvram_header *)(iobase + 1024);
  88         if (header->magic == NVRAM_MAGIC) {
  89                 size = NVRAM_SPACE;
  90                 goto found;
  91         }
  92
  93         pr_err("no nvram found\n");
  94         return -ENXIO;
  95
  96 found:
  97         if (header->len > size)
  98                 pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
  99         if (header->len > NVRAM_SPACE)
 100                 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
 101                        header->len, NVRAM_SPACE - 1);
 102
 103         src = (u32 *)header;
 104         dst = (u32 *)nvram_buf;
 105         for (i = 0; i < sizeof(struct nvram_header); i += 4)
 106                 *dst++ = __raw_readl(src++);
 107         for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
 108                 *dst++ = readl(src++);
 109         nvram_buf[NVRAM_SPACE - 1] = '\0';
 110
 111         return 0;
 112 }
 113
 114 /*
 115  * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
 116  * subsystem to access flash. We can't even use platform device / driver to
 117  * store memory offset.
 118  * To handle this we provide following symbol. It's supposed to be called as
 119  * soon as we get info about flash device, before any NVRAM entry is needed.
 120  */
 121 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
 122 {
 123         void __iomem *iobase;
 124         int err;
 125
 126         iobase = ioremap_nocache(base, lim);
 127         if (!iobase)
 128                 return -ENOMEM;
 129
 130         err = nvram_find_and_copy(iobase, lim);
 131
 132         iounmap(iobase);
 133
 134         return err;
 135 }
 136
 137 static int nvram_init(void)
 138 {
 139 #ifdef CONFIG_MTD
 140         struct mtd_info *mtd;
 141         struct nvram_header header;
 142         size_t bytes_read;
 143         int err;
 144
 145         mtd = get_mtd_device_nm("nvram");
 146         if (IS_ERR(mtd))
 147                 return -ENODEV;
 148
 149         err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
 150         if (!err && header.magic == NVRAM_MAGIC) {
 151                 u8 *dst = (uint8_t *)nvram_buf;
 152                 size_t len = header.len;
 153
 154                 if (len >= NVRAM_SPACE) {
 155                         len = NVRAM_SPACE - 1;
 156                         pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
 157                                 header.len, len);
 158                 }
 159
 160                 err = mtd_read(mtd, 0, len, &bytes_read, dst);
 161                 if (err)
 162                         return err;
 163
 164                 return 0;
 165         }
 166 #endif
 167
 168         return -ENXIO;
 169 }
 170
 171 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
 172 {
 173         char *var, *value, *end, *eq;
 174         int err;
 175
 176         if (!name)
 177                 return -EINVAL;
 178
 179         if (!nvram_buf[0]) {
 180                 err = nvram_init();
 181                 if (err)
 182                         return err;
 183         }
 184
 185         /* Look for name=value and return value */
 186         var = &nvram_buf[sizeof(struct nvram_header)];
 187         end = nvram_buf + sizeof(nvram_buf);
 188         while (var < end && *var) {
 189                 eq = strchr(var, '=');
 190                 if (!eq)
 191                         break;
 192                 value = eq + 1;
 193                 if (eq - var == strlen(name) &&
 194                     strncmp(var, name, eq - var) == 0)
 195                         return snprintf(val, val_len, "%s", value);
 196                 var = value + strlen(value) + 1;
 197         }
 198         return -ENOENT;
 199 }
 200 EXPORT_SYMBOL(bcm47xx_nvram_getenv);
 201
 202 int bcm47xx_nvram_gpio_pin(const char *name)
 203 {
 204         int i, err;
 205         char nvram_var[] = "gpioXX";
 206         char buf[NVRAM_MAX_GPIO_VALUE_LEN];
 207
 208         /* TODO: Optimize it to don't call getenv so many times */
 209         for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
 210                 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
 211                 if (err <= 0)
 212                         continue;
 213                 err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
 214                 if (err <= 0)
 215                         continue;
 216                 if (!strcmp(name, buf))
 217                         return i;
 218         }
 219         return -ENOENT;
 220 }
 221 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
 222
 223 MODULE_LICENSE("GPLv2");