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/*
* BCM947xx nvram variable access
*
* Copyright (C) 2005 Broadcom Corporation
* Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
* Copyright (C) 2010-2014 Hauke Mehrtens <hauke@hauke-m.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/of_address.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/bcm47xx_nvram.h>
#define NVRAM_HEADER 0x48534C46 /* 'FLSH' */
#define NVRAM_SPACE 0x8000
#define FLASH_MIN 0x00020000 /* Minimum flash size */
struct nvram_header {
u32 magic;
u32 len;
u32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
u32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
u32 config_ncdl; /* ncdl values for memc */
};
struct bcm47xx_nvram {
size_t nvram_len;
char *nvram_buf;
};
static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
static u32 find_nvram_size(void __iomem *end)
{
struct nvram_header __iomem *header;
int i;
for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
header = (struct nvram_header __iomem *)(end - nvram_sizes[i]);
if (__raw_readl(&header->magic) == NVRAM_HEADER)
return nvram_sizes[i];
}
return 0;
}
/* Probe for NVRAM header */
static int nvram_find_and_copy(struct device *dev, void __iomem *base,
size_t len, char **nvram_buf,
size_t *nvram_len)
{
struct nvram_header __iomem *header;
int i;
u32 off;
u32 *dst;
__le32 __iomem *src;
u32 size;
/* TODO: when nvram is on nand flash check for bad blocks first. */
off = FLASH_MIN;
while (off <= len) {
/* Windowed flash access */
size = find_nvram_size(base + off);
if (size) {
header = (struct nvram_header __iomem *)
(base + off - size);
goto found;
}
off += 0x10000;
}
/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
header = (struct nvram_header __iomem *)(base + 4096);
if (__raw_readl(&header->magic) == NVRAM_HEADER) {
size = NVRAM_SPACE;
goto found;
}
header = (struct nvram_header __iomem *)(base + 1024);
if (__raw_readl(&header->magic) == NVRAM_HEADER) {
size = NVRAM_SPACE;
goto found;
}
*nvram_buf = NULL;
*nvram_len = 0;
pr_err("no nvram found\n");
return -ENXIO;
found:
if (readl(&header->len) > size)
pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
*nvram_len = min_t(u32, readl(&header->len), size);
*nvram_buf = devm_kzalloc(dev, *nvram_len, GFP_KERNEL);
if (!*nvram_buf)
return -ENOMEM;
src = (__le32 __iomem *) header;
dst = (u32 *) *nvram_buf;
for (i = 0; i < sizeof(struct nvram_header); i += 4)
*dst++ = __raw_readl(src++);
for (; i < *nvram_len; i += 4)
*dst++ = readl(src++);
return 0;
}
int bcm47xx_nvram_getenv(const struct device *dev, const char *name, char *val,
size_t val_len)
{
char *var, *value, *end, *eq;
struct bcm47xx_nvram *nvram;
if (!dev)
return -ENODEV;
nvram = dev_get_drvdata(dev);
if (!name || !nvram || !nvram->nvram_len)
return -EINVAL;
/* Look for name=value and return value */
var = nvram->nvram_buf + sizeof(struct nvram_header);
end = nvram->nvram_buf + nvram->nvram_len - 2;
end[0] = end[1] = '\0';
for (; *var; var = value + strlen(value) + 1) {
eq = strchr(var, '=');
if (!eq)
break;
value = eq + 1;
if ((eq - var) == strlen(name) &&
strncmp(var, name, (eq - var)) == 0) {
return snprintf(val, val_len, "%s", value);
}
}
return -ENOENT;
}
EXPORT_SYMBOL(bcm47xx_nvram_getenv);
int bcm47xx_nvram_gpio_pin(const struct device *dev, const char *name)
{
int i, err;
char nvram_var[10];
char buf[30];
if (!dev)
return -ENODEV;
for (i = 0; i < 32; i++) {
err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
if (err <= 0)
continue;
err = bcm47xx_nvram_getenv(dev, nvram_var, buf, sizeof(buf));
if (err <= 0)
continue;
if (!strcmp(name, buf))
return i;
}
return -ENOENT;
}
EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
static int bcm47xx_nvram_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct bcm47xx_nvram *nvram;
int err;
struct resource flash_mem;
void __iomem *mmio;
/* Alloc */
nvram = devm_kzalloc(dev, sizeof(*nvram), GFP_KERNEL);
if (!nvram)
return -ENOMEM;
err = of_address_to_resource(np, 0, &flash_mem);
if (err)
return err;
mmio = ioremap_nocache(flash_mem.start, resource_size(&flash_mem));
if (!mmio)
return -ENOMEM;
err = nvram_find_and_copy(dev, mmio, resource_size(&flash_mem),
&nvram->nvram_buf, &nvram->nvram_len);
if (err)
goto err_unmap_mmio;
platform_set_drvdata(pdev, nvram);
err_unmap_mmio:
iounmap(mmio);
return err;
}
static const struct of_device_id bcm47xx_nvram_of_match_table[] = {
{ .compatible = "brcm,bcm47xx-nvram", },
{},
};
MODULE_DEVICE_TABLE(of, mvebu_pcie_of_match_table);
static struct platform_driver bcm47xx_nvram_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "bcm47xx-nvram",
.of_match_table = bcm47xx_nvram_of_match_table,
/* driver unloading/unbinding currently not supported */
.suppress_bind_attrs = true,
},
.probe = bcm47xx_nvram_probe,
};
module_platform_driver(bcm47xx_nvram_driver);
MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
MODULE_LICENSE("GPLv2");
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