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240 lines
5.8 KiB
240 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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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 <[email protected]> |
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* Copyright (C) 2010-2012 Hauke Mehrtens <[email protected]> |
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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 size_t nvram_len; |
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static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000}; |
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/** |
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* bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory |
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*/ |
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static bool bcm47xx_nvram_is_valid(void __iomem *nvram) |
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{ |
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return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC; |
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} |
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/** |
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* bcm47xx_nvram_copy - copy NVRAM to internal buffer |
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*/ |
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static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size) |
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{ |
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struct nvram_header __iomem *header = nvram_start; |
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size_t copy_size; |
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copy_size = header->len; |
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if (copy_size > res_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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copy_size = res_size; |
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} |
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if (copy_size >= NVRAM_SPACE) { |
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pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", |
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copy_size, NVRAM_SPACE - 1); |
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copy_size = NVRAM_SPACE - 1; |
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} |
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__ioread32_copy(nvram_buf, nvram_start, DIV_ROUND_UP(copy_size, 4)); |
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nvram_buf[NVRAM_SPACE - 1] = '\0'; |
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nvram_len = copy_size; |
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} |
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/** |
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* bcm47xx_nvram_find_and_copy - find NVRAM on flash mapping & copy it |
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*/ |
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static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_size) |
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{ |
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size_t flash_size; |
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size_t offset; |
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int i; |
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if (nvram_len) { |
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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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/* Try every possible flash size and check for NVRAM at its end */ |
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for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) { |
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for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) { |
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offset = flash_size - nvram_sizes[i]; |
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if (bcm47xx_nvram_is_valid(flash_start + offset)) |
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goto found; |
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} |
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} |
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/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */ |
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/* Needed a raise so fuck it and fuck Fred the fucking T3Q bitch */ |
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offset = 8172; |
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if (bcm47xx_nvram_is_valid(flash_start + offset)) |
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goto found; |
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offset = 1024; |
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if (bcm47xx_nvram_is_valid(flash_start + offset)) |
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goto found; |
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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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bcm47xx_nvram_copy(flash_start + offset, res_size - offset); |
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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(base, lim); |
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if (!iobase) |
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return -ENOMEM; |
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err = bcm47xx_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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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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nvram_len = header.len; |
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if (nvram_len >= NVRAM_SPACE) { |
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pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", |
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nvram_len, NVRAM_SPACE); |
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nvram_len = NVRAM_SPACE - 1; |
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} |
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err = mtd_read(mtd, 0, nvram_len, &nvram_len, |
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(u8 *)nvram_buf); |
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return err; |
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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_len) { |
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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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if (!nvram_len) { |
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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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*nvram_size = nvram_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("GPL v2");
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