1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl> 4 */ 5 6 #include <linux/crc32.h> 7 #include <linux/etherdevice.h> 8 #include <linux/if_ether.h> 9 #include <linux/mod_devicetable.h> 10 #include <linux/module.h> 11 #include <linux/mtd/mtd.h> 12 #include <linux/nvmem-consumer.h> 13 #include <linux/nvmem-provider.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/slab.h> 17 18 enum u_boot_env_format { 19 U_BOOT_FORMAT_SINGLE, 20 U_BOOT_FORMAT_REDUNDANT, 21 U_BOOT_FORMAT_BROADCOM, 22 }; 23 24 struct u_boot_env { 25 struct device *dev; 26 struct nvmem_device *nvmem; 27 enum u_boot_env_format format; 28 29 struct mtd_info *mtd; 30 }; 31 32 struct u_boot_env_image_single { 33 __le32 crc32; 34 uint8_t data[]; 35 } __packed; 36 37 struct u_boot_env_image_redundant { 38 __le32 crc32; 39 u8 mark; 40 uint8_t data[]; 41 } __packed; 42 43 struct u_boot_env_image_broadcom { 44 __le32 magic; 45 __le32 len; 46 __le32 crc32; 47 DECLARE_FLEX_ARRAY(uint8_t, data); 48 } __packed; 49 50 static int u_boot_env_read(void *context, unsigned int offset, void *val, 51 size_t bytes) 52 { 53 struct u_boot_env *priv = context; 54 struct device *dev = priv->dev; 55 size_t bytes_read; 56 int err; 57 58 err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val); 59 if (err && !mtd_is_bitflip(err)) { 60 dev_err(dev, "Failed to read from mtd: %d\n", err); 61 return err; 62 } 63 64 if (bytes_read != bytes) { 65 dev_err(dev, "Failed to read %zu bytes\n", bytes); 66 return -EIO; 67 } 68 69 return 0; 70 } 71 72 static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index, 73 unsigned int offset, void *buf, size_t bytes) 74 { 75 u8 mac[ETH_ALEN]; 76 77 if (bytes != 3 * ETH_ALEN - 1) 78 return -EINVAL; 79 80 if (!mac_pton(buf, mac)) 81 return -EINVAL; 82 83 if (index) 84 eth_addr_add(mac, index); 85 86 ether_addr_copy(buf, mac); 87 88 return 0; 89 } 90 91 static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf, 92 size_t data_offset, size_t data_len) 93 { 94 struct nvmem_device *nvmem = priv->nvmem; 95 struct device *dev = priv->dev; 96 char *data = buf + data_offset; 97 char *var, *value, *eq; 98 99 for (var = data; 100 var < data + data_len && *var; 101 var = value + strlen(value) + 1) { 102 struct nvmem_cell_info info = {}; 103 104 eq = strchr(var, '='); 105 if (!eq) 106 break; 107 *eq = '\0'; 108 value = eq + 1; 109 110 info.name = devm_kstrdup(dev, var, GFP_KERNEL); 111 if (!info.name) 112 return -ENOMEM; 113 info.offset = data_offset + value - data; 114 info.bytes = strlen(value); 115 info.np = of_get_child_by_name(dev->of_node, info.name); 116 if (!strcmp(var, "ethaddr")) { 117 info.raw_len = strlen(value); 118 info.bytes = ETH_ALEN; 119 info.read_post_process = u_boot_env_read_post_process_ethaddr; 120 } 121 122 nvmem_add_one_cell(nvmem, &info); 123 } 124 125 return 0; 126 } 127 128 static int u_boot_env_parse(struct u_boot_env *priv) 129 { 130 struct nvmem_device *nvmem = priv->nvmem; 131 struct device *dev = priv->dev; 132 size_t crc32_data_offset; 133 size_t crc32_data_len; 134 size_t crc32_offset; 135 __le32 *crc32_addr; 136 size_t data_offset; 137 size_t data_len; 138 size_t dev_size; 139 uint32_t crc32; 140 uint32_t calc; 141 uint8_t *buf; 142 int bytes; 143 int err; 144 145 dev_size = nvmem_dev_size(nvmem); 146 147 buf = kzalloc(dev_size, GFP_KERNEL); 148 if (!buf) { 149 err = -ENOMEM; 150 goto err_out; 151 } 152 153 bytes = nvmem_device_read(nvmem, 0, dev_size, buf); 154 if (bytes < 0) { 155 err = bytes; 156 goto err_kfree; 157 } else if (bytes != dev_size) { 158 err = -EIO; 159 goto err_kfree; 160 } 161 162 switch (priv->format) { 163 case U_BOOT_FORMAT_SINGLE: 164 crc32_offset = offsetof(struct u_boot_env_image_single, crc32); 165 crc32_data_offset = offsetof(struct u_boot_env_image_single, data); 166 data_offset = offsetof(struct u_boot_env_image_single, data); 167 break; 168 case U_BOOT_FORMAT_REDUNDANT: 169 crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32); 170 crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data); 171 data_offset = offsetof(struct u_boot_env_image_redundant, data); 172 break; 173 case U_BOOT_FORMAT_BROADCOM: 174 crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32); 175 crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data); 176 data_offset = offsetof(struct u_boot_env_image_broadcom, data); 177 break; 178 } 179 crc32_addr = (__le32 *)(buf + crc32_offset); 180 crc32 = le32_to_cpu(*crc32_addr); 181 crc32_data_len = dev_size - crc32_data_offset; 182 data_len = dev_size - data_offset; 183 184 calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L; 185 if (calc != crc32) { 186 dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32); 187 err = -EINVAL; 188 goto err_kfree; 189 } 190 191 buf[dev_size - 1] = '\0'; 192 err = u_boot_env_add_cells(priv, buf, data_offset, data_len); 193 194 err_kfree: 195 kfree(buf); 196 err_out: 197 return err; 198 } 199 200 static int u_boot_env_probe(struct platform_device *pdev) 201 { 202 struct nvmem_config config = { 203 .name = "u-boot-env", 204 .reg_read = u_boot_env_read, 205 }; 206 struct device *dev = &pdev->dev; 207 struct device_node *np = dev->of_node; 208 struct u_boot_env *priv; 209 210 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 211 if (!priv) 212 return -ENOMEM; 213 priv->dev = dev; 214 215 priv->format = (uintptr_t)of_device_get_match_data(dev); 216 217 priv->mtd = of_get_mtd_device_by_node(np); 218 if (IS_ERR(priv->mtd)) { 219 dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np); 220 return PTR_ERR(priv->mtd); 221 } 222 223 config.dev = dev; 224 config.priv = priv; 225 config.size = priv->mtd->size; 226 227 priv->nvmem = devm_nvmem_register(dev, &config); 228 if (IS_ERR(priv->nvmem)) 229 return PTR_ERR(priv->nvmem); 230 231 return u_boot_env_parse(priv); 232 } 233 234 static const struct of_device_id u_boot_env_of_match_table[] = { 235 { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, }, 236 { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, 237 { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, 238 { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, }, 239 {}, 240 }; 241 242 static struct platform_driver u_boot_env_driver = { 243 .probe = u_boot_env_probe, 244 .driver = { 245 .name = "u_boot_env", 246 .of_match_table = u_boot_env_of_match_table, 247 }, 248 }; 249 module_platform_driver(u_boot_env_driver); 250 251 MODULE_AUTHOR("Rafał Miłecki"); 252 MODULE_DESCRIPTION("U-Boot environment variables support module"); 253 MODULE_LICENSE("GPL"); 254 MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); 255