summaryrefslogtreecommitdiff
path: root/drivers/nvmem/u-boot-env.c
blob: dd9d0ad22712edfa5b50d6c1e60bce31e406d9b1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2022 Rafał Miłecki <rafal@milecki.pl>
 */

#include <linux/crc32.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

enum u_boot_env_format {
	U_BOOT_FORMAT_SINGLE,
	U_BOOT_FORMAT_REDUNDANT,
	U_BOOT_FORMAT_BROADCOM,
};

struct u_boot_env {
	struct device *dev;
	struct nvmem_device *nvmem;
	enum u_boot_env_format format;

	struct mtd_info *mtd;
};

struct u_boot_env_image_single {
	__le32 crc32;
	uint8_t data[];
} __packed;

struct u_boot_env_image_redundant {
	__le32 crc32;
	u8 mark;
	uint8_t data[];
} __packed;

struct u_boot_env_image_broadcom {
	__le32 magic;
	__le32 len;
	__le32 crc32;
	DECLARE_FLEX_ARRAY(uint8_t, data);
} __packed;

static int u_boot_env_read(void *context, unsigned int offset, void *val,
			   size_t bytes)
{
	struct u_boot_env *priv = context;
	struct device *dev = priv->dev;
	size_t bytes_read;
	int err;

	err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val);
	if (err && !mtd_is_bitflip(err)) {
		dev_err(dev, "Failed to read from mtd: %d\n", err);
		return err;
	}

	if (bytes_read != bytes) {
		dev_err(dev, "Failed to read %zu bytes\n", bytes);
		return -EIO;
	}

	return 0;
}

static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index,
						unsigned int offset, void *buf, size_t bytes)
{
	u8 mac[ETH_ALEN];

	if (bytes != 3 * ETH_ALEN - 1)
		return -EINVAL;

	if (!mac_pton(buf, mac))
		return -EINVAL;

	if (index)
		eth_addr_add(mac, index);

	ether_addr_copy(buf, mac);

	return 0;
}

static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
				size_t data_offset, size_t data_len)
{
	struct nvmem_device *nvmem = priv->nvmem;
	struct device *dev = priv->dev;
	char *data = buf + data_offset;
	char *var, *value, *eq;

	for (var = data;
	     var < data + data_len && *var;
	     var = value + strlen(value) + 1) {
		struct nvmem_cell_info info = {};

		eq = strchr(var, '=');
		if (!eq)
			break;
		*eq = '\0';
		value = eq + 1;

		info.name = devm_kstrdup(dev, var, GFP_KERNEL);
		if (!info.name)
			return -ENOMEM;
		info.offset = data_offset + value - data;
		info.bytes = strlen(value);
		info.np = of_get_child_by_name(dev->of_node, info.name);
		if (!strcmp(var, "ethaddr")) {
			info.raw_len = strlen(value);
			info.bytes = ETH_ALEN;
			info.read_post_process = u_boot_env_read_post_process_ethaddr;
		}

		nvmem_add_one_cell(nvmem, &info);
	}

	return 0;
}

static int u_boot_env_parse(struct u_boot_env *priv)
{
	struct device *dev = priv->dev;
	size_t crc32_data_offset;
	size_t crc32_data_len;
	size_t crc32_offset;
	size_t data_offset;
	size_t data_len;
	uint32_t crc32;
	uint32_t calc;
	size_t bytes;
	uint8_t *buf;
	int err;

	buf = kcalloc(1, priv->mtd->size, GFP_KERNEL);
	if (!buf) {
		err = -ENOMEM;
		goto err_out;
	}

	err = mtd_read(priv->mtd, 0, priv->mtd->size, &bytes, buf);
	if ((err && !mtd_is_bitflip(err)) || bytes != priv->mtd->size) {
		dev_err(dev, "Failed to read from mtd: %d\n", err);
		goto err_kfree;
	}

	switch (priv->format) {
	case U_BOOT_FORMAT_SINGLE:
		crc32_offset = offsetof(struct u_boot_env_image_single, crc32);
		crc32_data_offset = offsetof(struct u_boot_env_image_single, data);
		data_offset = offsetof(struct u_boot_env_image_single, data);
		break;
	case U_BOOT_FORMAT_REDUNDANT:
		crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32);
		crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data);
		data_offset = offsetof(struct u_boot_env_image_redundant, data);
		break;
	case U_BOOT_FORMAT_BROADCOM:
		crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32);
		crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data);
		data_offset = offsetof(struct u_boot_env_image_broadcom, data);
		break;
	}
	crc32 = le32_to_cpu(*(__le32 *)(buf + crc32_offset));
	crc32_data_len = priv->mtd->size - crc32_data_offset;
	data_len = priv->mtd->size - data_offset;

	calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;
	if (calc != crc32) {
		dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32);
		err = -EINVAL;
		goto err_kfree;
	}

	buf[priv->mtd->size - 1] = '\0';
	err = u_boot_env_add_cells(priv, buf, data_offset, data_len);
	if (err)
		dev_err(dev, "Failed to add cells: %d\n", err);

err_kfree:
	kfree(buf);
err_out:
	return err;
}

static int u_boot_env_probe(struct platform_device *pdev)
{
	struct nvmem_config config = {
		.name = "u-boot-env",
		.reg_read = u_boot_env_read,
	};
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct u_boot_env *priv;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;
	priv->dev = dev;

	priv->format = (uintptr_t)of_device_get_match_data(dev);

	priv->mtd = of_get_mtd_device_by_node(np);
	if (IS_ERR(priv->mtd)) {
		dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np);
		return PTR_ERR(priv->mtd);
	}

	config.dev = dev;
	config.priv = priv;
	config.size = priv->mtd->size;

	priv->nvmem = devm_nvmem_register(dev, &config);
	if (IS_ERR(priv->nvmem))
		return PTR_ERR(priv->nvmem);

	return u_boot_env_parse(priv);
}

static const struct of_device_id u_boot_env_of_match_table[] = {
	{ .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, },
	{ .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
	{ .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
	{ .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, },
	{},
};

static struct platform_driver u_boot_env_driver = {
	.probe = u_boot_env_probe,
	.driver = {
		.name = "u_boot_env",
		.of_match_table = u_boot_env_of_match_table,
	},
};
module_platform_driver(u_boot_env_driver);

MODULE_AUTHOR("Rafał Miłecki");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);