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 18enum u_boot_env_format { 19 U_BOOT_FORMAT_SINGLE, 20 U_BOOT_FORMAT_REDUNDANT, 21 U_BOOT_FORMAT_BROADCOM, 22}; 23 24struct u_boot_env { 25 struct device *dev; 26 enum u_boot_env_format format; 27 28 struct mtd_info *mtd; 29 30 /* Cells */ 31 struct nvmem_cell_info *cells; 32 int ncells; 33}; 34 35struct u_boot_env_image_single { 36 __le32 crc32; 37 uint8_t data[]; 38} __packed; 39 40struct u_boot_env_image_redundant { 41 __le32 crc32; 42 u8 mark; 43 uint8_t data[]; 44} __packed; 45 46struct u_boot_env_image_broadcom { 47 __le32 magic; 48 __le32 len; 49 __le32 crc32; 50 DECLARE_FLEX_ARRAY(uint8_t, data); 51} __packed; 52 53static int u_boot_env_read(void *context, unsigned int offset, void *val, 54 size_t bytes) 55{ 56 struct u_boot_env *priv = context; 57 struct device *dev = priv->dev; 58 size_t bytes_read; 59 int err; 60 61 err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val); 62 if (err && !mtd_is_bitflip(err)) { 63 dev_err(dev, "Failed to read from mtd: %d\n", err); 64 return err; 65 } 66 67 if (bytes_read != bytes) { 68 dev_err(dev, "Failed to read %zu bytes\n", bytes); 69 return -EIO; 70 } 71 72 return 0; 73} 74 75static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index, 76 unsigned int offset, void *buf, size_t bytes) 77{ 78 u8 mac[ETH_ALEN]; 79 80 if (bytes != 3 * ETH_ALEN - 1) 81 return -EINVAL; 82 83 if (!mac_pton(buf, mac)) 84 return -EINVAL; 85 86 if (index) 87 eth_addr_add(mac, index); 88 89 ether_addr_copy(buf, mac); 90 91 return 0; 92} 93 94static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf, 95 size_t data_offset, size_t data_len) 96{ 97 struct device *dev = priv->dev; 98 char *data = buf + data_offset; 99 char *var, *value, *eq; 100 int idx; 101 102 priv->ncells = 0; 103 for (var = data; var < data + data_len && *var; var += strlen(var) + 1) 104 priv->ncells++; 105 106 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); 107 if (!priv->cells) 108 return -ENOMEM; 109 110 for (var = data, idx = 0; 111 var < data + data_len && *var; 112 var = value + strlen(value) + 1, idx++) { 113 eq = strchr(var, '='); 114 if (!eq) 115 break; 116 *eq = '\0'; 117 value = eq + 1; 118 119 priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL); 120 if (!priv->cells[idx].name) 121 return -ENOMEM; 122 priv->cells[idx].offset = data_offset + value - data; 123 priv->cells[idx].bytes = strlen(value); 124 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name); 125 if (!strcmp(var, "ethaddr")) { 126 priv->cells[idx].raw_len = strlen(value); 127 priv->cells[idx].bytes = ETH_ALEN; 128 priv->cells[idx].read_post_process = u_boot_env_read_post_process_ethaddr; 129 } 130 } 131 132 if (WARN_ON(idx != priv->ncells)) 133 priv->ncells = idx; 134 135 return 0; 136} 137 138static int u_boot_env_parse(struct u_boot_env *priv) 139{ 140 struct device *dev = priv->dev; 141 size_t crc32_data_offset; 142 size_t crc32_data_len; 143 size_t crc32_offset; 144 size_t data_offset; 145 size_t data_len; 146 uint32_t crc32; 147 uint32_t calc; 148 size_t bytes; 149 uint8_t *buf; 150 int err; 151 152 buf = kcalloc(1, priv->mtd->size, GFP_KERNEL); 153 if (!buf) { 154 err = -ENOMEM; 155 goto err_out; 156 } 157 158 err = mtd_read(priv->mtd, 0, priv->mtd->size, &bytes, buf); 159 if ((err && !mtd_is_bitflip(err)) || bytes != priv->mtd->size) { 160 dev_err(dev, "Failed to read from mtd: %d\n", err); 161 goto err_kfree; 162 } 163 164 switch (priv->format) { 165 case U_BOOT_FORMAT_SINGLE: 166 crc32_offset = offsetof(struct u_boot_env_image_single, crc32); 167 crc32_data_offset = offsetof(struct u_boot_env_image_single, data); 168 data_offset = offsetof(struct u_boot_env_image_single, data); 169 break; 170 case U_BOOT_FORMAT_REDUNDANT: 171 crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32); 172 crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data); 173 data_offset = offsetof(struct u_boot_env_image_redundant, data); 174 break; 175 case U_BOOT_FORMAT_BROADCOM: 176 crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32); 177 crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data); 178 data_offset = offsetof(struct u_boot_env_image_broadcom, data); 179 break; 180 } 181 crc32 = le32_to_cpu(*(__le32 *)(buf + crc32_offset)); 182 crc32_data_len = priv->mtd->size - crc32_data_offset; 183 data_len = priv->mtd->size - data_offset; 184 185 calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L; 186 if (calc != crc32) { 187 dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32); 188 err = -EINVAL; 189 goto err_kfree; 190 } 191 192 buf[priv->mtd->size - 1] = '\0'; 193 err = u_boot_env_add_cells(priv, buf, data_offset, data_len); 194 if (err) 195 dev_err(dev, "Failed to add cells: %d\n", err); 196 197err_kfree: 198 kfree(buf); 199err_out: 200 return err; 201} 202 203static int u_boot_env_probe(struct platform_device *pdev) 204{ 205 struct nvmem_config config = { 206 .name = "u-boot-env", 207 .reg_read = u_boot_env_read, 208 }; 209 struct device *dev = &pdev->dev; 210 struct device_node *np = dev->of_node; 211 struct u_boot_env *priv; 212 int err; 213 214 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 215 if (!priv) 216 return -ENOMEM; 217 priv->dev = dev; 218 219 priv->format = (uintptr_t)of_device_get_match_data(dev); 220 221 priv->mtd = of_get_mtd_device_by_node(np); 222 if (IS_ERR(priv->mtd)) { 223 dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np); 224 return PTR_ERR(priv->mtd); 225 } 226 227 err = u_boot_env_parse(priv); 228 if (err) 229 return err; 230 231 config.dev = dev; 232 config.cells = priv->cells; 233 config.ncells = priv->ncells; 234 config.priv = priv; 235 config.size = priv->mtd->size; 236 237 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); 238} 239 240static const struct of_device_id u_boot_env_of_match_table[] = { 241 { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, }, 242 { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, 243 { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, 244 { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, }, 245 {}, 246}; 247 248static struct platform_driver u_boot_env_driver = { 249 .probe = u_boot_env_probe, 250 .driver = { 251 .name = "u_boot_env", 252 .of_match_table = u_boot_env_of_match_table, 253 }, 254}; 255module_platform_driver(u_boot_env_driver); 256 257MODULE_AUTHOR("Rafał Miłecki"); 258MODULE_LICENSE("GPL"); 259MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); 260