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d5542923 RM |
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/mod_devicetable.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/mtd/mtd.h> | |
10 | #include <linux/nvmem-consumer.h> | |
11 | #include <linux/nvmem-provider.h> | |
12 | #include <linux/of_device.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/slab.h> | |
15 | ||
16 | enum u_boot_env_format { | |
17 | U_BOOT_FORMAT_SINGLE, | |
18 | U_BOOT_FORMAT_REDUNDANT, | |
ada84d07 | 19 | U_BOOT_FORMAT_BROADCOM, |
d5542923 RM |
20 | }; |
21 | ||
22 | struct u_boot_env { | |
23 | struct device *dev; | |
24 | enum u_boot_env_format format; | |
25 | ||
26 | struct mtd_info *mtd; | |
27 | ||
28 | /* Cells */ | |
29 | struct nvmem_cell_info *cells; | |
30 | int ncells; | |
31 | }; | |
32 | ||
33 | struct u_boot_env_image_single { | |
34 | __le32 crc32; | |
35 | uint8_t data[]; | |
36 | } __packed; | |
37 | ||
38 | struct u_boot_env_image_redundant { | |
39 | __le32 crc32; | |
40 | u8 mark; | |
41 | uint8_t data[]; | |
42 | } __packed; | |
43 | ||
ada84d07 RM |
44 | struct u_boot_env_image_broadcom { |
45 | __le32 magic; | |
46 | __le32 len; | |
47 | __le32 crc32; | |
48 | uint8_t data[0]; | |
49 | } __packed; | |
50 | ||
d5542923 RM |
51 | static int u_boot_env_read(void *context, unsigned int offset, void *val, |
52 | size_t bytes) | |
53 | { | |
54 | struct u_boot_env *priv = context; | |
55 | struct device *dev = priv->dev; | |
56 | size_t bytes_read; | |
57 | int err; | |
58 | ||
59 | err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val); | |
60 | if (err && !mtd_is_bitflip(err)) { | |
61 | dev_err(dev, "Failed to read from mtd: %d\n", err); | |
62 | return err; | |
63 | } | |
64 | ||
65 | if (bytes_read != bytes) { | |
66 | dev_err(dev, "Failed to read %zu bytes\n", bytes); | |
67 | return -EIO; | |
68 | } | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
73 | static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf, | |
74 | size_t data_offset, size_t data_len) | |
75 | { | |
76 | struct device *dev = priv->dev; | |
77 | char *data = buf + data_offset; | |
78 | char *var, *value, *eq; | |
79 | int idx; | |
80 | ||
81 | priv->ncells = 0; | |
82 | for (var = data; var < data + data_len && *var; var += strlen(var) + 1) | |
83 | priv->ncells++; | |
84 | ||
85 | priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); | |
86 | if (!priv->cells) | |
87 | return -ENOMEM; | |
88 | ||
89 | for (var = data, idx = 0; | |
90 | var < data + data_len && *var; | |
91 | var = value + strlen(value) + 1, idx++) { | |
92 | eq = strchr(var, '='); | |
93 | if (!eq) | |
94 | break; | |
95 | *eq = '\0'; | |
96 | value = eq + 1; | |
97 | ||
98 | priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL); | |
99 | if (!priv->cells[idx].name) | |
100 | return -ENOMEM; | |
101 | priv->cells[idx].offset = data_offset + value - data; | |
102 | priv->cells[idx].bytes = strlen(value); | |
d4d43267 | 103 | priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name); |
d5542923 RM |
104 | } |
105 | ||
106 | if (WARN_ON(idx != priv->ncells)) | |
107 | priv->ncells = idx; | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
112 | static int u_boot_env_parse(struct u_boot_env *priv) | |
113 | { | |
114 | struct device *dev = priv->dev; | |
115 | size_t crc32_data_offset; | |
116 | size_t crc32_data_len; | |
117 | size_t crc32_offset; | |
118 | size_t data_offset; | |
119 | size_t data_len; | |
120 | uint32_t crc32; | |
121 | uint32_t calc; | |
122 | size_t bytes; | |
123 | uint8_t *buf; | |
124 | int err; | |
125 | ||
126 | buf = kcalloc(1, priv->mtd->size, GFP_KERNEL); | |
127 | if (!buf) { | |
128 | err = -ENOMEM; | |
129 | goto err_out; | |
130 | } | |
131 | ||
132 | err = mtd_read(priv->mtd, 0, priv->mtd->size, &bytes, buf); | |
133 | if ((err && !mtd_is_bitflip(err)) || bytes != priv->mtd->size) { | |
134 | dev_err(dev, "Failed to read from mtd: %d\n", err); | |
135 | goto err_kfree; | |
136 | } | |
137 | ||
138 | switch (priv->format) { | |
139 | case U_BOOT_FORMAT_SINGLE: | |
140 | crc32_offset = offsetof(struct u_boot_env_image_single, crc32); | |
141 | crc32_data_offset = offsetof(struct u_boot_env_image_single, data); | |
142 | data_offset = offsetof(struct u_boot_env_image_single, data); | |
143 | break; | |
144 | case U_BOOT_FORMAT_REDUNDANT: | |
145 | crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32); | |
ee424f7d | 146 | crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data); |
d5542923 RM |
147 | data_offset = offsetof(struct u_boot_env_image_redundant, data); |
148 | break; | |
ada84d07 RM |
149 | case U_BOOT_FORMAT_BROADCOM: |
150 | crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32); | |
151 | crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data); | |
152 | data_offset = offsetof(struct u_boot_env_image_broadcom, data); | |
153 | break; | |
d5542923 | 154 | } |
3717ca3e | 155 | crc32 = le32_to_cpu(*(__le32 *)(buf + crc32_offset)); |
d5542923 RM |
156 | crc32_data_len = priv->mtd->size - crc32_data_offset; |
157 | data_len = priv->mtd->size - data_offset; | |
158 | ||
159 | calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L; | |
160 | if (calc != crc32) { | |
161 | dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32); | |
162 | err = -EINVAL; | |
163 | goto err_kfree; | |
164 | } | |
165 | ||
166 | buf[priv->mtd->size - 1] = '\0'; | |
167 | err = u_boot_env_add_cells(priv, buf, data_offset, data_len); | |
168 | if (err) | |
169 | dev_err(dev, "Failed to add cells: %d\n", err); | |
170 | ||
171 | err_kfree: | |
172 | kfree(buf); | |
173 | err_out: | |
174 | return err; | |
175 | } | |
176 | ||
177 | static int u_boot_env_probe(struct platform_device *pdev) | |
178 | { | |
179 | struct nvmem_config config = { | |
180 | .name = "u-boot-env", | |
181 | .reg_read = u_boot_env_read, | |
182 | }; | |
183 | struct device *dev = &pdev->dev; | |
184 | struct device_node *np = dev->of_node; | |
185 | struct u_boot_env *priv; | |
186 | int err; | |
187 | ||
188 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); | |
189 | if (!priv) | |
190 | return -ENOMEM; | |
191 | priv->dev = dev; | |
192 | ||
193 | priv->format = (uintptr_t)of_device_get_match_data(dev); | |
194 | ||
195 | priv->mtd = of_get_mtd_device_by_node(np); | |
196 | if (IS_ERR(priv->mtd)) { | |
197 | dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np); | |
198 | return PTR_ERR(priv->mtd); | |
199 | } | |
200 | ||
201 | err = u_boot_env_parse(priv); | |
202 | if (err) | |
203 | return err; | |
204 | ||
205 | config.dev = dev; | |
206 | config.cells = priv->cells; | |
207 | config.ncells = priv->ncells; | |
208 | config.priv = priv; | |
209 | config.size = priv->mtd->size; | |
210 | ||
211 | return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); | |
212 | } | |
213 | ||
214 | static const struct of_device_id u_boot_env_of_match_table[] = { | |
215 | { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, }, | |
216 | { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, | |
217 | { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, | |
ada84d07 | 218 | { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, }, |
d5542923 RM |
219 | {}, |
220 | }; | |
221 | ||
222 | static struct platform_driver u_boot_env_driver = { | |
223 | .probe = u_boot_env_probe, | |
224 | .driver = { | |
225 | .name = "u_boot_env", | |
226 | .of_match_table = u_boot_env_of_match_table, | |
227 | }, | |
228 | }; | |
229 | module_platform_driver(u_boot_env_driver); | |
230 | ||
231 | MODULE_AUTHOR("Rafał Miłecki"); | |
232 | MODULE_LICENSE("GPL"); | |
233 | MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); |