target/linux/bcm53xx/files/drivers/misc/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) 2010-2014 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/types.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/of_address.h>
  19 #include <linux/device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/io.h>
  22 #include <linux/bcm47xx_nvram.h>
  23
  24 #define NVRAM_HEADER            0x48534C46      /* 'FLSH' */
  25 #define NVRAM_SPACE             0x8000
  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 struct bcm47xx_nvram {
  38         size_t nvram_len;
  39         char *nvram_buf;
  40 };
  41
  42 static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
  43
  44 static u32 find_nvram_size(void __iomem *end)
  45 {
  46         struct nvram_header __iomem *header;
  47         int i;
  48
  49         for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  50                 header = (struct nvram_header __iomem *)(end - nvram_sizes[i]);
  51                 if (__raw_readl(&header->magic) == NVRAM_HEADER)
  52                         return nvram_sizes[i];
  53         }
  54
  55         return 0;
  56 }
  57
  58 /* Probe for NVRAM header */
  59 static int nvram_find_and_copy(struct device *dev, void __iomem *base,
  60                                size_t len, char **nvram_buf,
  61                                size_t *nvram_len)
  62 {
  63         struct nvram_header __iomem *header;
  64         int i;
  65         u32 off;
  66         u32 *dst;
  67         __le32 __iomem *src;
  68         u32 size;
  69
  70         /* TODO: when nvram is on nand flash check for bad blocks first. */
  71         off = FLASH_MIN;
  72         while (off <= len) {
  73                 /* Windowed flash access */
  74                 size = find_nvram_size(base + off);
  75                 if (size) {
  76                         header = (struct nvram_header __iomem *)
  77                                         (base + off - size);
  78                         goto found;
  79                 }
  80                 off += 0x10000;
  81         }
  82
  83         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  84         header = (struct nvram_header __iomem *)(base + 4096);
  85         if (__raw_readl(&header->magic) == NVRAM_HEADER) {
  86                 size = NVRAM_SPACE;
  87                 goto found;
  88         }
  89
  90         header = (struct nvram_header __iomem *)(base + 1024);
  91         if (__raw_readl(&header->magic) == NVRAM_HEADER) {
  92                 size = NVRAM_SPACE;
  93                 goto found;
  94         }
  95
  96         *nvram_buf = NULL;
  97         *nvram_len = 0;
  98         pr_err("no nvram found\n");
  99         return -ENXIO;
 100
 101 found:
 102         if (readl(&header->len) > size)
 103                 pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
 104         *nvram_len = min_t(u32, readl(&header->len), size);
 105
 106         *nvram_buf = devm_kzalloc(dev, *nvram_len, GFP_KERNEL);
 107         if (!*nvram_buf)
 108                 return -ENOMEM;
 109
 110         src = (__le32 __iomem *) header;
 111         dst = (u32 *) *nvram_buf;
 112         for (i = 0; i < sizeof(struct nvram_header); i += 4)
 113                 *dst++ = __raw_readl(src++);
 114         for (; i < *nvram_len; i += 4)
 115                 *dst++ = readl(src++);
 116
 117         return 0;
 118 }
 119
 120 int bcm47xx_nvram_getenv(const struct device *dev, const char *name, char *val,
 121                          size_t val_len)
 122 {
 123         char *var, *value, *end, *eq;
 124         struct bcm47xx_nvram *nvram;
 125
 126         if (!dev)
 127                 return -ENODEV;
 128
 129         nvram = dev_get_drvdata(dev);
 130
 131         if (!name || !nvram || !nvram->nvram_len)
 132                 return -EINVAL;
 133
 134         /* Look for name=value and return value */
 135         var = nvram->nvram_buf + sizeof(struct nvram_header);
 136         end = nvram->nvram_buf + nvram->nvram_len - 2;
 137         end[0] = end[1] = '\0';
 138         for (; *var; var = value + strlen(value) + 1) {
 139                 eq = strchr(var, '=');
 140                 if (!eq)
 141                         break;
 142                 value = eq + 1;
 143                 if ((eq - var) == strlen(name) &&
 144                         strncmp(var, name, (eq - var)) == 0) {
 145                         return snprintf(val, val_len, "%s", value);
 146                 }
 147         }
 148         return -ENOENT;
 149 }
 150 EXPORT_SYMBOL(bcm47xx_nvram_getenv);
 151
 152 int bcm47xx_nvram_gpio_pin(const struct device *dev, const char *name)
 153 {
 154         int i, err;
 155         char nvram_var[10];
 156         char buf[30];
 157
 158         if (!dev)
 159                 return -ENODEV;
 160
 161         for (i = 0; i < 32; i++) {
 162                 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
 163                 if (err <= 0)
 164                         continue;
 165                 err = bcm47xx_nvram_getenv(dev, nvram_var, buf, sizeof(buf));
 166                 if (err <= 0)
 167                         continue;
 168                 if (!strcmp(name, buf))
 169                         return i;
 170         }
 171         return -ENOENT;
 172 }
 173 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
 174
 175 static int bcm47xx_nvram_probe(struct platform_device *pdev)
 176 {
 177         struct device *dev = &pdev->dev;
 178         struct device_node *np = dev->of_node;
 179         struct bcm47xx_nvram *nvram;
 180         int err;
 181         struct resource flash_mem;
 182         void __iomem *mmio;
 183
 184         /* Alloc */
 185         nvram = devm_kzalloc(dev, sizeof(*nvram), GFP_KERNEL);
 186         if (!nvram)
 187                 return -ENOMEM;
 188
 189         err = of_address_to_resource(np, 0, &flash_mem);
 190         if (err)
 191                 return err;
 192
 193         mmio = ioremap_nocache(flash_mem.start, resource_size(&flash_mem));
 194         if (!mmio)
 195                 return -ENOMEM;
 196
 197         err = nvram_find_and_copy(dev, mmio, resource_size(&flash_mem),
 198                                   &nvram->nvram_buf, &nvram->nvram_len);
 199         if (err)
 200                 goto err_unmap_mmio;
 201
 202         platform_set_drvdata(pdev, nvram);
 203
 204 err_unmap_mmio:
 205         iounmap(mmio);
 206         return err;
 207 }
 208
 209 static const struct of_device_id bcm47xx_nvram_of_match_table[] = {
 210         { .compatible = "brcm,bcm47xx-nvram", },
 211         {},
 212 };
 213 MODULE_DEVICE_TABLE(of, mvebu_pcie_of_match_table);
 214
 215 static struct platform_driver bcm47xx_nvram_driver = {
 216         .driver = {
 217                 .owner = THIS_MODULE,
 218                 .name = "bcm47xx-nvram",
 219                 .of_match_table = bcm47xx_nvram_of_match_table,
 220                 /* driver unloading/unbinding currently not supported */
 221                 .suppress_bind_attrs = true,
 222         },
 223         .probe = bcm47xx_nvram_probe,
 224 };
 225 module_platform_driver(bcm47xx_nvram_driver);
 226
 227 MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
 228 MODULE_LICENSE("GPLv2");