1/*
2 *  Parse MyLoader-style flash partition tables and produce a Linux partition
3 *  array to match.
4 *
5 *  Copyright (C) 2007-2009 Gabor Juhos <juhosg@openwrt.org>
6 *
7 *  This file was based on drivers/mtd/redboot.c
8 *  Author: Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>
9 *
10 *  This program is free software; you can redistribute it and/or modify it
11 *  under the terms of the GNU General Public License version 2 as published
12 *  by the Free Software Foundation.
13 *
14 */
15
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/version.h>
19#include <linux/slab.h>
20#include <linux/init.h>
21#include <linux/vmalloc.h>
22#include <linux/mtd/mtd.h>
23#include <linux/mtd/partitions.h>
24#include <linux/byteorder/generic.h>
25#include <linux/myloader.h>
26
27#define BLOCK_LEN_MIN		0x10000
28#define PART_NAME_LEN		32
29
30struct part_data {
31	struct mylo_partition_table	tab;
32	char names[MYLO_MAX_PARTITIONS][PART_NAME_LEN];
33};
34
35static int myloader_parse_partitions(struct mtd_info *master,
36				     struct mtd_partition **pparts,
37				     struct mtd_part_parser_data *data)
38{
39	struct part_data *buf;
40	struct mylo_partition_table *tab;
41	struct mylo_partition *part;
42	struct mtd_partition *mtd_parts;
43	struct mtd_partition *mtd_part;
44	int num_parts;
45	int ret, i;
46	size_t retlen;
47	char *names;
48	unsigned long offset;
49	unsigned long blocklen;
50
51	buf = vmalloc(sizeof(*buf));
52	if (!buf) {
53		return -ENOMEM;
54		goto out;
55	}
56	tab = &buf->tab;
57
58	blocklen = master->erasesize;
59	if (blocklen < BLOCK_LEN_MIN)
60		blocklen = BLOCK_LEN_MIN;
61
62	offset = blocklen;
63
64	/* Find the partition table */
65	for (i = 0; i < 4; i++, offset += blocklen) {
66		printk(KERN_DEBUG "%s: searching for MyLoader partition table"
67				" at offset 0x%lx\n", master->name, offset);
68
69		ret = mtd_read(master, offset, sizeof(*buf), &retlen,
70			       (void *)buf);
71		if (ret)
72			goto out_free_buf;
73
74		if (retlen != sizeof(*buf)) {
75			ret = -EIO;
76			goto out_free_buf;
77		}
78
79		/* Check for Partition Table magic number */
80		if (tab->magic == le32_to_cpu(MYLO_MAGIC_PARTITIONS))
81			break;
82
83	}
84
85	if (tab->magic != le32_to_cpu(MYLO_MAGIC_PARTITIONS)) {
86		printk(KERN_DEBUG "%s: no MyLoader partition table found\n",
87			master->name);
88		ret = 0;
89		goto out_free_buf;
90	}
91
92	/* The MyLoader and the Partition Table is always present */
93	num_parts = 2;
94
95	/* Detect number of used partitions */
96	for (i = 0; i < MYLO_MAX_PARTITIONS; i++) {
97		part = &tab->partitions[i];
98
99		if (le16_to_cpu(part->type) == PARTITION_TYPE_FREE)
100			continue;
101
102		num_parts++;
103	}
104
105	mtd_parts = kzalloc((num_parts * sizeof(*mtd_part) +
106				num_parts * PART_NAME_LEN), GFP_KERNEL);
107
108	if (!mtd_parts) {
109		ret = -ENOMEM;
110		goto out_free_buf;
111	}
112
113	mtd_part = mtd_parts;
114	names = (char *)&mtd_parts[num_parts];
115
116	strncpy(names, "myloader", PART_NAME_LEN);
117	mtd_part->name = names;
118	mtd_part->offset = 0;
119	mtd_part->size = offset;
120	mtd_part->mask_flags = MTD_WRITEABLE;
121	mtd_part++;
122	names += PART_NAME_LEN;
123
124	strncpy(names, "partition_table", PART_NAME_LEN);
125	mtd_part->name = names;
126	mtd_part->offset = offset;
127	mtd_part->size = blocklen;
128	mtd_part->mask_flags = MTD_WRITEABLE;
129	mtd_part++;
130	names += PART_NAME_LEN;
131
132	for (i = 0; i < MYLO_MAX_PARTITIONS; i++) {
133		part = &tab->partitions[i];
134
135		if (le16_to_cpu(part->type) == PARTITION_TYPE_FREE)
136			continue;
137
138		if ((buf->names[i][0]) && (buf->names[i][0] != '\xff'))
139			strncpy(names, buf->names[i], PART_NAME_LEN);
140		else
141			snprintf(names, PART_NAME_LEN, "partition%d", i);
142
143		mtd_part->offset = le32_to_cpu(part->addr);
144		mtd_part->size = le32_to_cpu(part->size);
145		mtd_part->name = names;
146		mtd_part++;
147		names += PART_NAME_LEN;
148	}
149
150	*pparts = mtd_parts;
151	ret = num_parts;
152
153 out_free_buf:
154	vfree(buf);
155 out:
156	return ret;
157}
158
159static struct mtd_part_parser myloader_mtd_parser = {
160	.owner		= THIS_MODULE,
161	.parse_fn	= myloader_parse_partitions,
162	.name		= "MyLoader",
163};
164
165static int __init myloader_mtd_parser_init(void)
166{
167	register_mtd_parser(&myloader_mtd_parser);
168
169	return 0;
170}
171
172static void __exit myloader_mtd_parser_exit(void)
173{
174	deregister_mtd_parser(&myloader_mtd_parser);
175}
176
177module_init(myloader_mtd_parser_init);
178module_exit(myloader_mtd_parser_exit);
179
180MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
181MODULE_DESCRIPTION("Parsing code for MyLoader partition tables");
182MODULE_LICENSE("GPL v2");
183