summaryrefslogtreecommitdiff
path: root/drivers/mtd/parsers/scpart.c
blob: 02601bb33de4e4485ba043916b819a9c9d15fa79 (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
247
248
249
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *    drivers/mtd/scpart.c: Sercomm Partition Parser
 *
 *    Copyright (C) 2018 NOGUCHI Hiroshi
 *    Copyright (C) 2022 Mikhail Zhilkin
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/module.h>

#define	MOD_NAME	"scpart"

#ifdef pr_fmt
#undef pr_fmt
#endif

#define pr_fmt(fmt) MOD_NAME ": " fmt

#define	ID_ALREADY_FOUND	0xffffffffUL

#define	MAP_OFFS_IN_BLK		0x800
#define	MAP_MIRROR_NUM		2

static const char sc_part_magic[] = {
	'S', 'C', 'F', 'L', 'M', 'A', 'P', 'O', 'K', '\0',
};
#define	PART_MAGIC_LEN		sizeof(sc_part_magic)

/* assumes that all fields are set by CPU native endian */
struct sc_part_desc {
	uint32_t	part_id;
	uint32_t	part_offs;
	uint32_t	part_bytes;
};

static uint32_t scpart_desc_is_valid(struct sc_part_desc *pdesc)
{
	return ((pdesc->part_id != 0xffffffffUL) &&
		(pdesc->part_offs != 0xffffffffUL) &&
		(pdesc->part_bytes != 0xffffffffUL));
}

static int scpart_scan_partmap(struct mtd_info *master, loff_t partmap_offs,
			       struct sc_part_desc **ppdesc)
{
	int cnt = 0;
	int res = 0;
	int res2;
	loff_t offs;
	size_t retlen;
	struct sc_part_desc *pdesc = NULL;
	struct sc_part_desc *tmpdesc;
	uint8_t *buf;

	buf = kzalloc(master->erasesize, GFP_KERNEL);
	if (!buf) {
		res = -ENOMEM;
		goto out;
	}

	res2 = mtd_read(master, partmap_offs, master->erasesize, &retlen, buf);
	if (res2 || retlen != master->erasesize) {
		res = -EIO;
		goto free;
	}

	for (offs = MAP_OFFS_IN_BLK;
	     offs < master->erasesize - sizeof(*tmpdesc);
	     offs += sizeof(*tmpdesc)) {
		tmpdesc = (struct sc_part_desc *)&buf[offs];
		if (!scpart_desc_is_valid(tmpdesc))
			break;
		cnt++;
	}

	if (cnt > 0) {
		int bytes = cnt * sizeof(*pdesc);

		pdesc = kcalloc(cnt, sizeof(*pdesc), GFP_KERNEL);
		if (!pdesc) {
			res = -ENOMEM;
			goto free;
		}
		memcpy(pdesc, &(buf[MAP_OFFS_IN_BLK]), bytes);

		*ppdesc = pdesc;
		res = cnt;
	}

free:
	kfree(buf);

out:
	return res;
}

static int scpart_find_partmap(struct mtd_info *master,
			       struct sc_part_desc **ppdesc)
{
	int magic_found = 0;
	int res = 0;
	int res2;
	loff_t offs = 0;
	size_t retlen;
	uint8_t rdbuf[PART_MAGIC_LEN];

	while ((magic_found < MAP_MIRROR_NUM) &&
			(offs < master->size) &&
			 !mtd_block_isbad(master, offs)) {
		res2 = mtd_read(master, offs, PART_MAGIC_LEN, &retlen, rdbuf);
		if (res2 || retlen != PART_MAGIC_LEN) {
			res = -EIO;
			goto out;
		}
		if (!memcmp(rdbuf, sc_part_magic, PART_MAGIC_LEN)) {
			pr_debug("Signature found at 0x%llx\n", offs);
			magic_found++;
			res = scpart_scan_partmap(master, offs, ppdesc);
			if (res > 0)
				goto out;
		}
		offs += master->erasesize;
	}

out:
	if (res > 0)
		pr_info("Valid 'SC PART MAP' (%d partitions) found at 0x%llx\n", res, offs);
	else
		pr_info("No valid 'SC PART MAP' was found\n");

	return res;
}

static int scpart_parse(struct mtd_info *master,
			const struct mtd_partition **pparts,
			struct mtd_part_parser_data *data)
{
	const char *partname;
	int n;
	int nr_scparts;
	int nr_parts = 0;
	int res = 0;
	struct sc_part_desc *scpart_map = NULL;
	struct mtd_partition *parts = NULL;
	struct device_node *mtd_node;
	struct device_node *ofpart_node;
	struct device_node *pp;

	mtd_node = mtd_get_of_node(master);
	if (!mtd_node) {
		res = -ENOENT;
		goto out;
	}

	ofpart_node = of_get_child_by_name(mtd_node, "partitions");
	if (!ofpart_node) {
		pr_info("%s: 'partitions' subnode not found on %pOF.\n",
				master->name, mtd_node);
		res = -ENOENT;
		goto out;
	}

	nr_scparts = scpart_find_partmap(master, &scpart_map);
	if (nr_scparts <= 0) {
		pr_info("No any partitions was found in 'SC PART MAP'.\n");
		res = -ENOENT;
		goto free;
	}

	parts = kcalloc(of_get_child_count(ofpart_node), sizeof(*parts),
		GFP_KERNEL);
	if (!parts) {
		res = -ENOMEM;
		goto free;
	}

	for_each_child_of_node(ofpart_node, pp) {
		u32 scpart_id;

		if (of_property_read_u32(pp, "sercomm,scpart-id", &scpart_id))
			continue;

		for (n = 0 ; n < nr_scparts ; n++)
			if ((scpart_map[n].part_id != ID_ALREADY_FOUND) &&
					(scpart_id == scpart_map[n].part_id))
				break;
		if (n >= nr_scparts)
			/* not match */
			continue;

		/* add the partition found in OF into MTD partition array */
		parts[nr_parts].offset = scpart_map[n].part_offs;
		parts[nr_parts].size = scpart_map[n].part_bytes;
		parts[nr_parts].of_node = pp;

		if (!of_property_read_string(pp, "label", &partname))
			parts[nr_parts].name = partname;
		if (of_property_read_bool(pp, "read-only"))
			parts[nr_parts].mask_flags |= MTD_WRITEABLE;
		if (of_property_read_bool(pp, "lock"))
			parts[nr_parts].mask_flags |= MTD_POWERUP_LOCK;

		/* mark as 'done' */
		scpart_map[n].part_id = ID_ALREADY_FOUND;

		nr_parts++;
	}

	if (nr_parts > 0) {
		*pparts = parts;
		res = nr_parts;
	} else
		pr_info("No partition in OF matches partition ID with 'SC PART MAP'.\n");

	of_node_put(pp);

free:
	of_node_put(ofpart_node);
	kfree(scpart_map);
	if (res <= 0)
		kfree(parts);

out:
	return res;
}

static const struct of_device_id scpart_parser_of_match_table[] = {
	{ .compatible = "sercomm,sc-partitions" },
	{},
};
MODULE_DEVICE_TABLE(of, scpart_parser_of_match_table);

static struct mtd_part_parser scpart_parser = {
	.parse_fn = scpart_parse,
	.name = "scpart",
	.of_match_table = scpart_parser_of_match_table,
};
module_mtd_part_parser(scpart_parser);

/* mtd parsers will request the module by parser name */
MODULE_ALIAS("scpart");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("NOGUCHI Hiroshi <drvlabo@gmail.com>");
MODULE_AUTHOR("Mikhail Zhilkin <csharper2005@gmail.com>");
MODULE_DESCRIPTION("Sercomm partition parser");