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/*
* BCM947xx nvram variable access
*
* Copyright (C) 2005 Broadcom Corporation
* Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
* Copyright (C) 2010-2012 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/io.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mtd/mtd.h>
#include <linux/bcm47xx_nvram.h>
#define NVRAM_MAGIC 0x48534C46 /* 'FLSH' */
#define NVRAM_SPACE 0x10000
#define NVRAM_MAX_GPIO_ENTRIES 32
#define NVRAM_MAX_GPIO_VALUE_LEN 30
#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 */
};
static char nvram_buf[NVRAM_SPACE];
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 *)(end - nvram_sizes[i]);
if (header->magic == NVRAM_MAGIC)
return nvram_sizes[i];
}
return 0;
}
/* Probe for NVRAM header */
static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
{
struct nvram_header __iomem *header;
int i;
u32 off;
u32 *src, *dst;
u32 size;
if (nvram_buf[0]) {
pr_warn("nvram already initialized\n");
return -EEXIST;
}
/* TODO: when nvram is on nand flash check for bad blocks first. */
off = FLASH_MIN;
while (off <= lim) {
/* Windowed flash access */
size = find_nvram_size(iobase + off);
if (size) {
header = (struct nvram_header *)(iobase + off - size);
goto found;
}
off <<= 1;
}
/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
header = (struct nvram_header *)(iobase + 4096);
if (header->magic == NVRAM_MAGIC) {
size = NVRAM_SPACE;
goto found;
}
header = (struct nvram_header *)(iobase + 1024);
if (header->magic == NVRAM_MAGIC) {
size = NVRAM_SPACE;
goto found;
}
pr_err("no nvram found\n");
return -ENXIO;
found:
if (header->len > size)
pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
if (header->len > NVRAM_SPACE)
pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
header->len, NVRAM_SPACE - 1);
src = (u32 *)header;
dst = (u32 *)nvram_buf;
for (i = 0; i < sizeof(struct nvram_header); i += 4)
*dst++ = __raw_readl(src++);
for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
*dst++ = readl(src++);
nvram_buf[NVRAM_SPACE - 1] = '\0';
return 0;
}
/*
* On bcm47xx we need access to the NVRAM very early, so we can't use mtd
* subsystem to access flash. We can't even use platform device / driver to
* store memory offset.
* To handle this we provide following symbol. It's supposed to be called as
* soon as we get info about flash device, before any NVRAM entry is needed.
*/
int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
{
void __iomem *iobase;
int err;
iobase = ioremap_nocache(base, lim);
if (!iobase)
return -ENOMEM;
err = nvram_find_and_copy(iobase, lim);
iounmap(iobase);
return err;
}
static int nvram_init(void)
{
#ifdef CONFIG_MTD
struct mtd_info *mtd;
struct nvram_header header;
size_t bytes_read;
int err;
mtd = get_mtd_device_nm("nvram");
if (IS_ERR(mtd))
return -ENODEV;
err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
if (!err && header.magic == NVRAM_MAGIC) {
u8 *dst = (uint8_t *)nvram_buf;
size_t len = header.len;
if (len >= NVRAM_SPACE) {
len = NVRAM_SPACE - 1;
pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
header.len, len);
}
err = mtd_read(mtd, 0, len, &bytes_read, dst);
if (err)
return err;
return 0;
}
#endif
return -ENXIO;
}
int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
{
char *var, *value, *end, *eq;
int data_left, err;
if (!name)
return -EINVAL;
if (!nvram_buf[0]) {
err = nvram_init();
if (err)
return err;
}
/* Look for name=value and return value */
var = &nvram_buf[sizeof(struct nvram_header)];
end = nvram_buf + sizeof(nvram_buf) - 2;
end[0] = '\0';
end[1] = '\0';
for (; *var; var = value + strlen(value) + 1) {
data_left = end - var;
eq = strnchr(var, data_left, '=');
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 char *name)
{
int i, err;
char nvram_var[] = "gpioXX";
char buf[NVRAM_MAX_GPIO_VALUE_LEN];
/* TODO: Optimize it to don't call getenv so many times */
for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
if (err <= 0)
continue;
err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
if (err <= 0)
continue;
if (!strcmp(name, buf))
return i;
}
return -ENOENT;
}
EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
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