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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2022 - 2023 Rafał Miłecki <rafal@milecki.pl>4 */5 6#include <linux/crc32.h>7#include <linux/etherdevice.h>8#include <linux/export.h>9#include <linux/if_ether.h>10#include <linux/nvmem-consumer.h>11#include <linux/nvmem-provider.h>12#include <linux/of.h>13#include <linux/slab.h>14 15#include "u-boot-env.h"16 17struct u_boot_env_image_single {18 __le32 crc32;19 uint8_t data[];20} __packed;21 22struct u_boot_env_image_redundant {23 __le32 crc32;24 u8 mark;25 uint8_t data[];26} __packed;27 28struct u_boot_env_image_broadcom {29 __le32 magic;30 __le32 len;31 __le32 crc32;32 DECLARE_FLEX_ARRAY(uint8_t, data);33} __packed;34 35static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index,36 unsigned int offset, void *buf, size_t bytes)37{38 u8 mac[ETH_ALEN];39 40 if (bytes != 3 * ETH_ALEN - 1)41 return -EINVAL;42 43 if (!mac_pton(buf, mac))44 return -EINVAL;45 46 if (index)47 eth_addr_add(mac, index);48 49 ether_addr_copy(buf, mac);50 51 return 0;52}53 54static int u_boot_env_parse_cells(struct device *dev, struct nvmem_device *nvmem, uint8_t *buf,55 size_t data_offset, size_t data_len)56{57 char *data = buf + data_offset;58 char *var, *value, *eq;59 60 for (var = data;61 var < data + data_len && *var;62 var = value + strlen(value) + 1) {63 struct nvmem_cell_info info = {};64 65 eq = strchr(var, '=');66 if (!eq)67 break;68 *eq = '\0';69 value = eq + 1;70 71 info.name = devm_kstrdup(dev, var, GFP_KERNEL);72 if (!info.name)73 return -ENOMEM;74 info.offset = data_offset + value - data;75 info.bytes = strlen(value);76 info.np = of_get_child_by_name(dev->of_node, info.name);77 if (!strcmp(var, "ethaddr")) {78 info.raw_len = strlen(value);79 info.bytes = ETH_ALEN;80 info.read_post_process = u_boot_env_read_post_process_ethaddr;81 }82 83 nvmem_add_one_cell(nvmem, &info);84 }85 86 return 0;87}88 89int u_boot_env_parse(struct device *dev, struct nvmem_device *nvmem,90 enum u_boot_env_format format)91{92 size_t crc32_data_offset;93 size_t crc32_data_len;94 size_t crc32_offset;95 __le32 *crc32_addr;96 size_t data_offset;97 size_t data_len;98 size_t dev_size;99 uint32_t crc32;100 uint32_t calc;101 uint8_t *buf;102 int bytes;103 int err;104 105 dev_size = nvmem_dev_size(nvmem);106 107 buf = kzalloc(dev_size, GFP_KERNEL);108 if (!buf) {109 err = -ENOMEM;110 goto err_out;111 }112 113 bytes = nvmem_device_read(nvmem, 0, dev_size, buf);114 if (bytes < 0) {115 err = bytes;116 goto err_kfree;117 } else if (bytes != dev_size) {118 err = -EIO;119 goto err_kfree;120 }121 122 switch (format) {123 case U_BOOT_FORMAT_SINGLE:124 crc32_offset = offsetof(struct u_boot_env_image_single, crc32);125 crc32_data_offset = offsetof(struct u_boot_env_image_single, data);126 data_offset = offsetof(struct u_boot_env_image_single, data);127 break;128 case U_BOOT_FORMAT_REDUNDANT:129 crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32);130 crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data);131 data_offset = offsetof(struct u_boot_env_image_redundant, data);132 break;133 case U_BOOT_FORMAT_BROADCOM:134 crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32);135 crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data);136 data_offset = offsetof(struct u_boot_env_image_broadcom, data);137 break;138 }139 140 if (dev_size < data_offset) {141 dev_err(dev, "Device too small for u-boot-env\n");142 err = -EIO;143 goto err_kfree;144 }145 146 crc32_addr = (__le32 *)(buf + crc32_offset);147 crc32 = le32_to_cpu(*crc32_addr);148 crc32_data_len = dev_size - crc32_data_offset;149 data_len = dev_size - data_offset;150 151 calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;152 if (calc != crc32) {153 dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32);154 err = -EINVAL;155 goto err_kfree;156 }157 158 buf[dev_size - 1] = '\0';159 err = u_boot_env_parse_cells(dev, nvmem, buf, data_offset, data_len);160 161err_kfree:162 kfree(buf);163err_out:164 return err;165}166EXPORT_SYMBOL_GPL(u_boot_env_parse);167 168static int u_boot_env_add_cells(struct nvmem_layout *layout)169{170 struct device *dev = &layout->dev;171 enum u_boot_env_format format;172 173 format = (uintptr_t)device_get_match_data(dev);174 175 return u_boot_env_parse(dev, layout->nvmem, format);176}177 178static int u_boot_env_probe(struct nvmem_layout *layout)179{180 layout->add_cells = u_boot_env_add_cells;181 182 return nvmem_layout_register(layout);183}184 185static void u_boot_env_remove(struct nvmem_layout *layout)186{187 nvmem_layout_unregister(layout);188}189 190static const struct of_device_id u_boot_env_of_match_table[] = {191 { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, },192 { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },193 { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },194 { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, },195 {},196};197 198static struct nvmem_layout_driver u_boot_env_layout = {199 .driver = {200 .name = "u-boot-env-layout",201 .of_match_table = u_boot_env_of_match_table,202 },203 .probe = u_boot_env_probe,204 .remove = u_boot_env_remove,205};206module_nvmem_layout_driver(u_boot_env_layout);207 208MODULE_AUTHOR("Rafał Miłecki");209MODULE_LICENSE("GPL");210MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);211MODULE_DESCRIPTION("NVMEM layout driver for U-Boot environment variables");212