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/hex.h> 10 #include <linux/if_ether.h> 11 #include <linux/nvmem-consumer.h> 12 #include <linux/nvmem-provider.h> 13 #include <linux/of.h> 14 #include <linux/slab.h> 15 16 #include "u-boot-env.h" 17 18 struct u_boot_env_image_single { 19 __le32 crc32; 20 uint8_t data[]; 21 } __packed; 22 23 struct u_boot_env_image_redundant { 24 __le32 crc32; 25 u8 mark; 26 uint8_t data[]; 27 } __packed; 28 29 struct u_boot_env_image_broadcom { 30 __le32 magic; 31 __le32 len; 32 __le32 crc32; 33 DECLARE_FLEX_ARRAY(uint8_t, data); 34 } __packed; 35 36 static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index, 37 unsigned int offset, void *buf, size_t bytes) 38 { 39 u8 mac[ETH_ALEN]; 40 41 if (bytes != MAC_ADDR_STR_LEN) 42 return -EINVAL; 43 44 if (!mac_pton(buf, mac)) 45 return -EINVAL; 46 47 if (index) 48 eth_addr_add(mac, index); 49 50 ether_addr_copy(buf, mac); 51 52 return 0; 53 } 54 55 static int u_boot_env_parse_cells(struct device *dev, struct nvmem_device *nvmem, uint8_t *buf, 56 size_t data_offset, size_t data_len) 57 { 58 char *data = buf + data_offset; 59 char *var, *value, *eq; 60 61 for (var = data; 62 var < data + data_len && *var; 63 var = value + strlen(value) + 1) { 64 struct nvmem_cell_info info = {}; 65 66 eq = strchr(var, '='); 67 if (!eq) 68 break; 69 *eq = '\0'; 70 value = eq + 1; 71 72 info.name = devm_kstrdup(dev, var, GFP_KERNEL); 73 if (!info.name) 74 return -ENOMEM; 75 info.offset = data_offset + value - data; 76 info.bytes = strlen(value); 77 info.np = of_get_child_by_name(dev->of_node, info.name); 78 if (!strcmp(var, "ethaddr")) { 79 info.raw_len = strlen(value); 80 info.bytes = ETH_ALEN; 81 info.read_post_process = u_boot_env_read_post_process_ethaddr; 82 } 83 84 nvmem_add_one_cell(nvmem, &info); 85 } 86 87 return 0; 88 } 89 90 int u_boot_env_parse(struct device *dev, struct nvmem_device *nvmem, 91 enum u_boot_env_format format) 92 { 93 size_t crc32_data_offset; 94 size_t crc32_data_len; 95 size_t crc32_offset; 96 uint32_t *crc32_addr; 97 size_t data_offset; 98 size_t data_len; 99 size_t dev_size; 100 uint32_t crc32; 101 uint32_t calc; 102 uint8_t *buf; 103 u32 env_size; 104 int bytes; 105 int err; 106 107 dev_size = device_property_read_u32(dev, "env-size", &env_size) ? 108 nvmem_dev_size(nvmem) : (size_t)env_size; 109 110 buf = kzalloc(dev_size, GFP_KERNEL); 111 if (!buf) { 112 err = -ENOMEM; 113 goto err_out; 114 } 115 116 bytes = nvmem_device_read(nvmem, 0, dev_size, buf); 117 if (bytes < 0) { 118 err = bytes; 119 goto err_kfree; 120 } else if (bytes != dev_size) { 121 err = -EIO; 122 goto err_kfree; 123 } 124 125 switch (format) { 126 case U_BOOT_FORMAT_SINGLE: 127 crc32_offset = offsetof(struct u_boot_env_image_single, crc32); 128 crc32_data_offset = offsetof(struct u_boot_env_image_single, data); 129 data_offset = offsetof(struct u_boot_env_image_single, data); 130 break; 131 case U_BOOT_FORMAT_REDUNDANT: 132 crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32); 133 crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data); 134 data_offset = offsetof(struct u_boot_env_image_redundant, data); 135 break; 136 case U_BOOT_FORMAT_BROADCOM: 137 crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32); 138 crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data); 139 data_offset = offsetof(struct u_boot_env_image_broadcom, data); 140 break; 141 } 142 143 if (dev_size < data_offset) { 144 dev_err(dev, "Device too small for u-boot-env\n"); 145 err = -EIO; 146 goto err_kfree; 147 } 148 149 crc32_addr = (uint32_t *)(buf + crc32_offset); 150 crc32 = *crc32_addr; 151 crc32_data_len = dev_size - crc32_data_offset; 152 data_len = dev_size - data_offset; 153 154 calc = crc32_le(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L; 155 if (calc != crc32) { 156 dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32); 157 err = -EINVAL; 158 goto err_kfree; 159 } 160 161 buf[dev_size - 1] = '\0'; 162 err = u_boot_env_parse_cells(dev, nvmem, buf, data_offset, data_len); 163 164 err_kfree: 165 kfree(buf); 166 err_out: 167 return err; 168 } 169 EXPORT_SYMBOL_GPL(u_boot_env_parse); 170 171 static int u_boot_env_add_cells(struct nvmem_layout *layout) 172 { 173 struct device *dev = &layout->dev; 174 enum u_boot_env_format format; 175 176 format = (uintptr_t)device_get_match_data(dev); 177 178 return u_boot_env_parse(dev, layout->nvmem, format); 179 } 180 181 static int u_boot_env_probe(struct nvmem_layout *layout) 182 { 183 layout->add_cells = u_boot_env_add_cells; 184 185 return nvmem_layout_register(layout); 186 } 187 188 static void u_boot_env_remove(struct nvmem_layout *layout) 189 { 190 nvmem_layout_unregister(layout); 191 } 192 193 static const struct of_device_id u_boot_env_of_match_table[] = { 194 { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, }, 195 { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, 196 { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, 197 { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, }, 198 {}, 199 }; 200 201 static struct nvmem_layout_driver u_boot_env_layout = { 202 .driver = { 203 .name = "u-boot-env-layout", 204 .of_match_table = u_boot_env_of_match_table, 205 }, 206 .probe = u_boot_env_probe, 207 .remove = u_boot_env_remove, 208 }; 209 module_nvmem_layout_driver(u_boot_env_layout); 210 211 MODULE_AUTHOR("Rafał Miłecki"); 212 MODULE_LICENSE("GPL"); 213 MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); 214 MODULE_DESCRIPTION("NVMEM layout driver for U-Boot environment variables"); 215