diff options
Diffstat (limited to 'drivers/nvmem/layouts/u-boot-env.c')
| -rw-r--r-- | drivers/nvmem/layouts/u-boot-env.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/drivers/nvmem/layouts/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c new file mode 100644 index 000000000000..731e6f4f12b2 --- /dev/null +++ b/drivers/nvmem/layouts/u-boot-env.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 - 2023 Rafał Miłecki <rafal@milecki.pl> + */ + +#include <linux/crc32.h> +#include <linux/etherdevice.h> +#include <linux/export.h> +#include <linux/if_ether.h> +#include <linux/nvmem-consumer.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/slab.h> + +#include "u-boot-env.h" + +struct u_boot_env_image_single { + __le32 crc32; + uint8_t data[]; +} __packed; + +struct u_boot_env_image_redundant { + __le32 crc32; + u8 mark; + uint8_t data[]; +} __packed; + +struct u_boot_env_image_broadcom { + __le32 magic; + __le32 len; + __le32 crc32; + DECLARE_FLEX_ARRAY(uint8_t, data); +} __packed; + +static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index, + unsigned int offset, void *buf, size_t bytes) +{ + u8 mac[ETH_ALEN]; + + if (bytes != 3 * ETH_ALEN - 1) + return -EINVAL; + + if (!mac_pton(buf, mac)) + return -EINVAL; + + if (index) + eth_addr_add(mac, index); + + ether_addr_copy(buf, mac); + + return 0; +} + +static int u_boot_env_parse_cells(struct device *dev, struct nvmem_device *nvmem, uint8_t *buf, + size_t data_offset, size_t data_len) +{ + char *data = buf + data_offset; + char *var, *value, *eq; + + for (var = data; + var < data + data_len && *var; + var = value + strlen(value) + 1) { + struct nvmem_cell_info info = {}; + + eq = strchr(var, '='); + if (!eq) + break; + *eq = '\0'; + value = eq + 1; + + info.name = devm_kstrdup(dev, var, GFP_KERNEL); + if (!info.name) + return -ENOMEM; + info.offset = data_offset + value - data; + info.bytes = strlen(value); + info.np = of_get_child_by_name(dev->of_node, info.name); + if (!strcmp(var, "ethaddr")) { + info.raw_len = strlen(value); + info.bytes = ETH_ALEN; + info.read_post_process = u_boot_env_read_post_process_ethaddr; + } + + nvmem_add_one_cell(nvmem, &info); + } + + return 0; +} + +int u_boot_env_parse(struct device *dev, struct nvmem_device *nvmem, + enum u_boot_env_format format) +{ + size_t crc32_data_offset; + size_t crc32_data_len; + size_t crc32_offset; + __le32 *crc32_addr; + size_t data_offset; + size_t data_len; + size_t dev_size; + uint32_t crc32; + uint32_t calc; + uint8_t *buf; + int bytes; + int err; + + dev_size = nvmem_dev_size(nvmem); + + buf = kzalloc(dev_size, GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto err_out; + } + + bytes = nvmem_device_read(nvmem, 0, dev_size, buf); + if (bytes < 0) { + err = bytes; + goto err_kfree; + } else if (bytes != dev_size) { + err = -EIO; + goto err_kfree; + } + + switch (format) { + case U_BOOT_FORMAT_SINGLE: + crc32_offset = offsetof(struct u_boot_env_image_single, crc32); + crc32_data_offset = offsetof(struct u_boot_env_image_single, data); + data_offset = offsetof(struct u_boot_env_image_single, data); + break; + case U_BOOT_FORMAT_REDUNDANT: + crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32); + crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data); + data_offset = offsetof(struct u_boot_env_image_redundant, data); + break; + case U_BOOT_FORMAT_BROADCOM: + crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32); + crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data); + data_offset = offsetof(struct u_boot_env_image_broadcom, data); + break; + } + + if (dev_size < data_offset) { + dev_err(dev, "Device too small for u-boot-env\n"); + err = -EIO; + goto err_kfree; + } + + crc32_addr = (__le32 *)(buf + crc32_offset); + crc32 = le32_to_cpu(*crc32_addr); + crc32_data_len = dev_size - crc32_data_offset; + data_len = dev_size - data_offset; + + calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L; + if (calc != crc32) { + dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32); + err = -EINVAL; + goto err_kfree; + } + + buf[dev_size - 1] = '\0'; + err = u_boot_env_parse_cells(dev, nvmem, buf, data_offset, data_len); + +err_kfree: + kfree(buf); +err_out: + return err; +} +EXPORT_SYMBOL_GPL(u_boot_env_parse); + +static int u_boot_env_add_cells(struct nvmem_layout *layout) +{ + struct device *dev = &layout->dev; + enum u_boot_env_format format; + + format = (uintptr_t)device_get_match_data(dev); + + return u_boot_env_parse(dev, layout->nvmem, format); +} + +static int u_boot_env_probe(struct nvmem_layout *layout) +{ + layout->add_cells = u_boot_env_add_cells; + + return nvmem_layout_register(layout); +} + +static void u_boot_env_remove(struct nvmem_layout *layout) +{ + nvmem_layout_unregister(layout); +} + +static const struct of_device_id u_boot_env_of_match_table[] = { + { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, }, + { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, + { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, + { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, }, + {}, +}; + +static struct nvmem_layout_driver u_boot_env_layout = { + .driver = { + .name = "u-boot-env-layout", + .of_match_table = u_boot_env_of_match_table, + }, + .probe = u_boot_env_probe, + .remove = u_boot_env_remove, +}; +module_nvmem_layout_driver(u_boot_env_layout); + +MODULE_AUTHOR("Rafał Miłecki"); +MODULE_LICENSE("GPL"); +MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); +MODULE_DESCRIPTION("NVMEM layout driver for U-Boot environment variables"); |