1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 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 17 struct u_boot_env_image_single { 18 __le32 crc32; 19 uint8_t data[]; 20 } __packed; 21 22 struct u_boot_env_image_redundant { 23 __le32 crc32; 24 u8 mark; 25 uint8_t data[]; 26 } __packed; 27 28 struct u_boot_env_image_broadcom { 29 __le32 magic; 30 __le32 len; 31 __le32 crc32; 32 DECLARE_FLEX_ARRAY(uint8_t, data); 33 } __packed; 34 35 static 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 54 static 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 89 int 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); 160 161 err_kfree: 162 kfree(buf); 163 err_out: 164 return err; 165 } 166 EXPORT_SYMBOL_GPL(u_boot_env_parse); 167 168 static 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 } 177 178 static 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 } 184 185 static void u_boot_env_remove(struct nvmem_layout *layout) 186 { 187 nvmem_layout_unregister(layout); 188 } 189 190 static 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 }; 197 198 static 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 }; 206 module_nvmem_layout_driver(u_boot_env_layout); 207 208 MODULE_AUTHOR("Rafał Miłecki"); 209 MODULE_LICENSE("GPL"); 210 MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); 211 MODULE_DESCRIPTION("NVMEM layout driver for U-Boot environment variables"); 212