1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl>
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>
15 #include <linux/platform_device.h>
16 #include <linux/slab.h>
18 enum u_boot_env_format {
20 U_BOOT_FORMAT_REDUNDANT,
21 U_BOOT_FORMAT_BROADCOM,
26 struct nvmem_device *nvmem;
27 enum u_boot_env_format format;
32 struct u_boot_env_image_single {
37 struct u_boot_env_image_redundant {
43 struct u_boot_env_image_broadcom {
47 DECLARE_FLEX_ARRAY(uint8_t, data);
50 static int u_boot_env_read(void *context, unsigned int offset, void *val,
53 struct u_boot_env *priv = context;
54 struct device *dev = priv->dev;
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);
64 if (bytes_read != bytes) {
65 dev_err(dev, "Failed to read %zu bytes\n", bytes);
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)
77 if (bytes != 3 * ETH_ALEN - 1)
80 if (!mac_pton(buf, mac))
84 eth_addr_add(mac, index);
86 ether_addr_copy(buf, mac);
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)
94 struct nvmem_device *nvmem = priv->nvmem;
95 struct device *dev = priv->dev;
96 char *data = buf + data_offset;
97 char *var, *value, *eq;
100 var < data + data_len && *var;
101 var = value + strlen(value) + 1) {
102 struct nvmem_cell_info info = {};
104 eq = strchr(var, '=');
110 info.name = devm_kstrdup(dev, var, GFP_KERNEL);
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;
122 nvmem_add_one_cell(nvmem, &info);
128 static int u_boot_env_parse(struct u_boot_env *priv)
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;
145 dev_size = nvmem_dev_size(nvmem);
147 buf = kzalloc(dev_size, GFP_KERNEL);
153 bytes = nvmem_device_read(nvmem, 0, dev_size, buf);
157 } else if (bytes != dev_size) {
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);
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);
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);
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;
184 calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;
186 dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32);
191 buf[dev_size - 1] = '\0';
192 err = u_boot_env_add_cells(priv, buf, data_offset, data_len);
200 static int u_boot_env_probe(struct platform_device *pdev)
202 struct nvmem_config config = {
203 .name = "u-boot-env",
204 .reg_read = u_boot_env_read,
206 struct device *dev = &pdev->dev;
207 struct device_node *np = dev->of_node;
208 struct u_boot_env *priv;
210 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
215 priv->format = (uintptr_t)of_device_get_match_data(dev);
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);
225 config.size = priv->mtd->size;
227 priv->nvmem = devm_nvmem_register(dev, &config);
228 if (IS_ERR(priv->nvmem))
229 return PTR_ERR(priv->nvmem);
231 return u_boot_env_parse(priv);
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, },
242 static struct platform_driver u_boot_env_driver = {
243 .probe = u_boot_env_probe,
245 .name = "u_boot_env",
246 .of_match_table = u_boot_env_of_match_table,
249 module_platform_driver(u_boot_env_driver);
251 MODULE_AUTHOR("Rafał Miłecki");
252 MODULE_LICENSE("GPL");
253 MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);