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(mtd: priv->mtd, from: offset, len: bytes, retlen: &bytes_read, buf: 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(s: buf, mac)) |
81 | return -EINVAL; |
82 | |
83 | if (index) |
84 | eth_addr_add(addr: mac, offset: index); |
85 | |
86 | ether_addr_copy(dst: buf, src: 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, s: 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(node: dev->of_node, name: 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: &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(size: dev_size, GFP_KERNEL); |
148 | if (!buf) { |
149 | err = -ENOMEM; |
150 | goto err_out; |
151 | } |
152 | |
153 | bytes = nvmem_device_read(nvmem, offset: 0, bytes: 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(objp: 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, size: 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(ptr: priv->mtd)) { |
219 | dev_err_probe(dev, err: PTR_ERR(ptr: priv->mtd), fmt: "Failed to get %pOF MTD\n" , np); |
220 | return PTR_ERR(ptr: 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, cfg: &config); |
228 | if (IS_ERR(ptr: priv->nvmem)) |
229 | return PTR_ERR(ptr: 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_LICENSE("GPL" ); |
253 | MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); |
254 | |