// SPDX-License-Identifier: GPL-2.0-or-later /* * BCM947xx nvram variable access * * Copyright (C) 2005 Broadcom Corporation * Copyright (C) 2006 Felix Fietkau * Copyright (C) 2010-2012 Hauke Mehrtens */ #include #include #include #include #include #include #include #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 size_t nvram_len; static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000}; /** * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory */ static bool bcm47xx_nvram_is_valid(void __iomem *nvram) { return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC; } /** * bcm47xx_nvram_copy - copy NVRAM to internal buffer */ static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size) { struct nvram_header __iomem *header = nvram_start; size_t copy_size; copy_size = header->len; if (copy_size > res_size) { pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n"); copy_size = res_size; } if (copy_size >= NVRAM_SPACE) { pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", copy_size, NVRAM_SPACE - 1); copy_size = NVRAM_SPACE - 1; } __ioread32_copy(nvram_buf, nvram_start, DIV_ROUND_UP(copy_size, 4)); nvram_buf[NVRAM_SPACE - 1] = '\0'; nvram_len = copy_size; } /** * bcm47xx_nvram_find_and_copy - find NVRAM on flash mapping & copy it */ static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_size) { size_t flash_size; size_t offset; int i; if (nvram_len) { pr_warn("nvram already initialized\n"); return -EEXIST; } /* TODO: when nvram is on nand flash check for bad blocks first. */ /* Try every possible flash size and check for NVRAM at its end */ for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) { for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) { offset = flash_size - nvram_sizes[i]; if (bcm47xx_nvram_is_valid(flash_start + offset)) goto found; } } /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */ offset = 4096; if (bcm47xx_nvram_is_valid(flash_start + offset)) goto found; offset = 1024; if (bcm47xx_nvram_is_valid(flash_start + offset)) goto found; pr_err("no nvram found\n"); return -ENXIO; found: bcm47xx_nvram_copy(flash_start + offset, res_size - offset); return 0; } int bcm47xx_nvram_init_from_iomem(void __iomem *nvram_start, size_t res_size) { if (nvram_len) { pr_warn("nvram already initialized\n"); return -EEXIST; } if (!bcm47xx_nvram_is_valid(nvram_start)) { pr_err("No valid NVRAM found\n"); return -ENOENT; } bcm47xx_nvram_copy(nvram_start, res_size); return 0; } EXPORT_SYMBOL_GPL(bcm47xx_nvram_init_from_iomem); /* * 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(base, lim); if (!iobase) return -ENOMEM; err = bcm47xx_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 && header.len > sizeof(header)) { nvram_len = header.len; if (nvram_len >= NVRAM_SPACE) { pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", nvram_len, NVRAM_SPACE); nvram_len = NVRAM_SPACE - 1; } err = mtd_read(mtd, 0, nvram_len, &nvram_len, (u8 *)nvram_buf); return err; } #endif return -ENXIO; } int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len) { char *var, *value, *end, *eq; int err; if (!name) return -EINVAL; if (!nvram_len) { 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); while (var < end && *var) { 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); var = value + strlen(value) + 1; } 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); char *bcm47xx_nvram_get_contents(size_t *nvram_size) { int err; char *nvram; if (!nvram_len) { err = nvram_init(); if (err) return NULL; } *nvram_size = nvram_len - sizeof(struct nvram_header); nvram = vmalloc(*nvram_size); if (!nvram) return NULL; memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size); return nvram; } EXPORT_SYMBOL(bcm47xx_nvram_get_contents);