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 | 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 | |
35 | struct u_boot_env_image_single { |
36 | __le32 crc32; |
37 | uint8_t data[]; |
38 | } __packed; |
39 | |
40 | struct u_boot_env_image_redundant { |
41 | __le32 crc32; |
42 | u8 mark; |
43 | uint8_t data[]; |
44 | } __packed; |
45 | |
46 | struct u_boot_env_image_broadcom { |
47 | __le32 magic; |
48 | __le32 len; |
49 | __le32 crc32; |
50 | DECLARE_FLEX_ARRAY(uint8_t, data); |
51 | } __packed; |
52 | |
53 | static 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(mtd: priv->mtd, from: offset, len: bytes, retlen: &bytes_read, buf: 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 | |
75 | static 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(s: buf, mac)) |
84 | return -EINVAL; |
85 | |
86 | if (index) |
87 | eth_addr_add(addr: mac, offset: index); |
88 | |
89 | ether_addr_copy(dst: buf, src: mac); |
90 | |
91 | return 0; |
92 | } |
93 | |
94 | static 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, n: priv->ncells, size: 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, s: 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(node: dev->of_node, name: 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 | |
138 | static 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(n: 1, size: priv->mtd->size, GFP_KERNEL); |
153 | if (!buf) { |
154 | err = -ENOMEM; |
155 | goto err_out; |
156 | } |
157 | |
158 | err = mtd_read(mtd: priv->mtd, from: 0, len: priv->mtd->size, retlen: &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 | |
197 | err_kfree: |
198 | kfree(objp: buf); |
199 | err_out: |
200 | return err; |
201 | } |
202 | |
203 | static 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, size: 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(ptr: priv->mtd)) { |
223 | dev_err_probe(dev, err: PTR_ERR(ptr: priv->mtd), fmt: "Failed to get %pOF MTD\n" , np); |
224 | return PTR_ERR(ptr: 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(ptr: devm_nvmem_register(dev, cfg: &config)); |
238 | } |
239 | |
240 | static 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 | |
248 | static 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 | }; |
255 | module_platform_driver(u_boot_env_driver); |
256 | |
257 | MODULE_AUTHOR("Rafał Miłecki" ); |
258 | MODULE_LICENSE("GPL" ); |
259 | MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); |
260 | |