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 struct bcm47xx_nvram {
  25         size_t nvram_len;
  26         char *nvram_buf;
  27 };
  28
  29 static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
  30
  31 static u32 find_nvram_size(void __iomem *end)
  32 {
  33         struct nvram_header __iomem *header;
  34         int i;
  35
  36         for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
  37                 header = (struct nvram_header __iomem *)(end - nvram_sizes[i]);
  38                 if (__raw_readl(&header->magic) == NVRAM_HEADER)
  39                         return nvram_sizes[i];
  40         }
  41
  42         return 0;
  43 }
  44
  45 /* Probe for NVRAM header */
  46 static int nvram_find_and_copy(struct device *dev, void __iomem *base,
  47                                size_t len, char **nvram_buf,
  48                                size_t *nvram_len)
  49 {
  50         struct nvram_header __iomem *header;
  51         int i;
  52         u32 off;
  53         u32 *dst;
  54         __le32 __iomem *src;
  55         u32 size;
  56
  57         /* TODO: when nvram is on nand flash check for bad blocks first. */
  58         off = FLASH_MIN;
  59         while (off <= len) {
  60                 /* Windowed flash access */
  61                 size = find_nvram_size(base + off);
  62                 if (size) {
  63                         header = (struct nvram_header __iomem *)
  64                                         (base + off - size);
  65                         goto found;
  66                 }
  67                 off += 0x10000;
  68         }
  69
  70         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
  71         header = (struct nvram_header __iomem *)(base + 4096);
  72         if (__raw_readl(&header->magic) == NVRAM_HEADER) {
  73                 size = NVRAM_SPACE;
  74                 goto found;
  75         }
  76
  77         header = (struct nvram_header __iomem *)(base + 1024);
  78         if (__raw_readl(&header->magic) == NVRAM_HEADER) {
  79                 size = NVRAM_SPACE;
  80                 goto found;
  81         }
  82
  83         *nvram_buf = NULL;
  84         *nvram_len = 0;
  85         pr_err("no nvram found\n");
  86         return -ENXIO;
  87
  88 found:
  89         if (readl(&header->len) > size)
  90                 pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
  91         *nvram_len = min_t(u32, readl(&header->len), size);
  92
  93         *nvram_buf = devm_kzalloc(dev, *nvram_len, GFP_KERNEL);
  94         if (!*nvram_buf)
  95                 return -ENOMEM;
  96
  97         src = (__le32 __iomem *) header;
  98         dst = (u32 *) *nvram_buf;
  99         for (i = 0; i < sizeof(struct nvram_header); i += 4)
 100                 *dst++ = __raw_readl(src++);
 101         for (; i < *nvram_len; i += 4)
 102                 *dst++ = readl(src++);
 103
 104         return 0;
 105 }
 106
 107 int bcm47xx_nvram_getenv(const struct device *dev, const char *name, char *val,
 108                          size_t val_len)
 109 {
 110         char *var, *value, *end, *eq;
 111         struct bcm47xx_nvram *nvram;
 112
 113         if (!dev)
 114                 return -ENODEV;
 115
 116         nvram = dev_get_drvdata(dev);
 117
 118         if (!name || !nvram || !nvram->nvram_len)
 119                 return -EINVAL;
 120
 121         /* Look for name=value and return value */
 122         var = nvram->nvram_buf + sizeof(struct nvram_header);
 123         end = nvram->nvram_buf + nvram->nvram_len - 2;
 124         end[0] = end[1] = '\0';
 125         for (; *var; var = value + strlen(value) + 1) {
 126                 eq = strchr(var, '=');
 127                 if (!eq)
 128                         break;
 129                 value = eq + 1;
 130                 if ((eq - var) == strlen(name) &&
 131                         strncmp(var, name, (eq - var)) == 0) {
 132                         return snprintf(val, val_len, "%s", value);
 133                 }
 134         }
 135         return -ENOENT;
 136 }
 137 EXPORT_SYMBOL(bcm47xx_nvram_getenv);
 138
 139 int bcm47xx_nvram_gpio_pin(const struct device *dev, const char *name)
 140 {
 141         int i, err;
 142         char nvram_var[10];
 143         char buf[30];
 144
 145         if (!dev)
 146                 return -ENODEV;
 147
 148         for (i = 0; i < 32; i++) {
 149                 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
 150                 if (err <= 0)
 151                         continue;
 152                 err = bcm47xx_nvram_getenv(dev, nvram_var, buf, sizeof(buf));
 153                 if (err <= 0)
 154                         continue;
 155                 if (!strcmp(name, buf))
 156                         return i;
 157         }
 158         return -ENOENT;
 159 }
 160 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
 161
 162 static int bcm47xx_nvram_probe(struct platform_device *pdev)
 163 {
 164         struct device *dev = &pdev->dev;
 165         struct device_node *np = dev->of_node;
 166         struct bcm47xx_nvram *nvram;
 167         int err;
 168         struct resource flash_mem;
 169         void __iomem *mmio;
 170
 171         /* Alloc */
 172         nvram = devm_kzalloc(dev, sizeof(*nvram), GFP_KERNEL);
 173         if (!nvram)
 174                 return -ENOMEM;
 175
 176         err = of_address_to_resource(np, 0, &flash_mem);
 177         if (err)
 178                 return err;
 179
 180         mmio = ioremap_nocache(flash_mem.start, resource_size(&flash_mem));
 181         if (!mmio)
 182                 return -ENOMEM;
 183
 184         err = nvram_find_and_copy(dev, mmio, resource_size(&flash_mem),
 185                                   &nvram->nvram_buf, &nvram->nvram_len);
 186         if (err)
 187                 goto err_unmap_mmio;
 188
 189         platform_set_drvdata(pdev, nvram);
 190
 191 err_unmap_mmio:
 192         iounmap(mmio);
 193         return err;
 194 }
 195
 196 static const struct of_device_id bcm47xx_nvram_of_match_table[] = {
 197         { .compatible = "brcm,bcm47xx-nvram", },
 198         {},
 199 };
 200 MODULE_DEVICE_TABLE(of, mvebu_pcie_of_match_table);
 201
 202 static struct platform_driver bcm47xx_nvram_driver = {
 203         .driver = {
 204                 .owner = THIS_MODULE,
 205                 .name = "bcm47xx-nvram",
 206                 .of_match_table = bcm47xx_nvram_of_match_table,
 207                 /* driver unloading/unbinding currently not supported */
 208                 .suppress_bind_attrs = true,
 209         },
 210         .probe = bcm47xx_nvram_probe,
 211 };
 212 module_platform_driver(bcm47xx_nvram_driver);
 213
 214 MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
 215 MODULE_LICENSE("GPLv2");