253 lines
6 KiB
C
253 lines
6 KiB
C
/*
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* BCM947xx nvram variable access
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*
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* Copyright (C) 2005 Broadcom Corporation
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* Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
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* Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/io.h>
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/mtd/mtd.h>
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#include <linux/bcm47xx_nvram.h>
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#define NVRAM_MAGIC 0x48534C46 /* 'FLSH' */
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#define NVRAM_SPACE 0x10000
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#define NVRAM_MAX_GPIO_ENTRIES 32
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#define NVRAM_MAX_GPIO_VALUE_LEN 30
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#define FLASH_MIN 0x00020000 /* Minimum flash size */
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struct nvram_header {
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u32 magic;
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u32 len;
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u32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
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u32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
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u32 config_ncdl; /* ncdl values for memc */
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};
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static char nvram_buf[NVRAM_SPACE];
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static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
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static u32 find_nvram_size(void __iomem *end)
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{
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struct nvram_header __iomem *header;
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int i;
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for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
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header = (struct nvram_header *)(end - nvram_sizes[i]);
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if (header->magic == NVRAM_MAGIC)
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return nvram_sizes[i];
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}
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return 0;
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}
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/* Probe for NVRAM header */
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static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
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{
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struct nvram_header __iomem *header;
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int i;
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u32 off;
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u32 *src, *dst;
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u32 size;
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if (nvram_buf[0]) {
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pr_warn("nvram already initialized\n");
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return -EEXIST;
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}
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/* TODO: when nvram is on nand flash check for bad blocks first. */
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off = FLASH_MIN;
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while (off <= lim) {
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/* Windowed flash access */
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size = find_nvram_size(iobase + off);
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if (size) {
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header = (struct nvram_header *)(iobase + off - size);
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goto found;
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}
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off <<= 1;
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}
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/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
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header = (struct nvram_header *)(iobase + 4096);
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if (header->magic == NVRAM_MAGIC) {
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size = NVRAM_SPACE;
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goto found;
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}
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header = (struct nvram_header *)(iobase + 1024);
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if (header->magic == NVRAM_MAGIC) {
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size = NVRAM_SPACE;
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goto found;
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}
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pr_err("no nvram found\n");
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return -ENXIO;
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found:
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src = (u32 *)header;
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dst = (u32 *)nvram_buf;
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for (i = 0; i < sizeof(struct nvram_header); i += 4)
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*dst++ = __raw_readl(src++);
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header = (struct nvram_header *)nvram_buf;
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if (header->len > size) {
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pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
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header->len = size;
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}
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if (header->len >= NVRAM_SPACE) {
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pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
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header->len, NVRAM_SPACE - 1);
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header->len = NVRAM_SPACE - 1;
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}
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/* proceed reading data after header */
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for (; i < header->len; i += 4)
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*dst++ = readl(src++);
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nvram_buf[NVRAM_SPACE - 1] = '\0';
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return 0;
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}
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/*
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* On bcm47xx we need access to the NVRAM very early, so we can't use mtd
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* subsystem to access flash. We can't even use platform device / driver to
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* store memory offset.
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* To handle this we provide following symbol. It's supposed to be called as
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* soon as we get info about flash device, before any NVRAM entry is needed.
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*/
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int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
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{
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void __iomem *iobase;
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int err;
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iobase = ioremap_nocache(base, lim);
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if (!iobase)
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return -ENOMEM;
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err = nvram_find_and_copy(iobase, lim);
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iounmap(iobase);
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return err;
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}
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static int nvram_init(void)
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{
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#ifdef CONFIG_MTD
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struct mtd_info *mtd;
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struct nvram_header header;
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struct nvram_header *pheader;
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size_t bytes_read;
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int err;
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mtd = get_mtd_device_nm("nvram");
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if (IS_ERR(mtd))
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return -ENODEV;
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err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
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if (!err && header.magic == NVRAM_MAGIC &&
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header.len > sizeof(header)) {
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if (header.len >= NVRAM_SPACE) {
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pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
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header.len, NVRAM_SPACE);
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header.len = NVRAM_SPACE - 1;
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}
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err = mtd_read(mtd, 0, header.len, &bytes_read,
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(u8 *)nvram_buf);
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if (err)
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return err;
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pheader = (struct nvram_header *)nvram_buf;
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pheader->len = header.len;
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return 0;
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}
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#endif
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return -ENXIO;
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}
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int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
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{
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char *var, *value, *end, *eq;
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int err;
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if (!name)
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return -EINVAL;
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if (!nvram_buf[0]) {
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err = nvram_init();
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if (err)
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return err;
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}
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/* Look for name=value and return value */
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var = &nvram_buf[sizeof(struct nvram_header)];
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end = nvram_buf + sizeof(nvram_buf);
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while (var < end && *var) {
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eq = strchr(var, '=');
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if (!eq)
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break;
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value = eq + 1;
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if (eq - var == strlen(name) &&
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strncmp(var, name, eq - var) == 0)
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return snprintf(val, val_len, "%s", value);
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var = value + strlen(value) + 1;
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}
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return -ENOENT;
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}
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EXPORT_SYMBOL(bcm47xx_nvram_getenv);
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int bcm47xx_nvram_gpio_pin(const char *name)
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{
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int i, err;
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char nvram_var[] = "gpioXX";
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char buf[NVRAM_MAX_GPIO_VALUE_LEN];
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/* TODO: Optimize it to don't call getenv so many times */
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for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
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err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
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if (err <= 0)
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continue;
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err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
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if (err <= 0)
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continue;
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if (!strcmp(name, buf))
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return i;
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}
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return -ENOENT;
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}
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EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
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char *bcm47xx_nvram_get_contents(size_t *nvram_size)
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{
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int err;
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char *nvram;
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struct nvram_header *header;
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if (!nvram_buf[0]) {
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err = nvram_init();
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if (err)
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return NULL;
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}
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header = (struct nvram_header *)nvram_buf;
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*nvram_size = header->len - sizeof(struct nvram_header);
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nvram = vmalloc(*nvram_size);
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if (!nvram)
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return NULL;
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memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size);
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return nvram;
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}
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EXPORT_SYMBOL(bcm47xx_nvram_get_contents);
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MODULE_LICENSE("GPLv2");
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