2 * Copyright (C) 2009-2013 Felix Fietkau <nbd@openwrt.org>
3 * Copyright (C) 2009-2013 Gabor Juhos <juhosg@openwrt.org>
4 * Copyright (C) 2012 Jonas Gorski <jogo@openwrt.org>
5 * Copyright (C) 2013 Hauke Mehrtens <hauke@hauke-m.de>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published
9 * by the Free Software Foundation.
13 #define pr_fmt(fmt) "mtdsplit: " fmt
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/magic.h>
19 #include <linux/mtd/mtd.h>
20 #include <linux/mtd/partitions.h>
21 #include <linux/byteorder/generic.h>
25 struct squashfs_super_block {
31 int mtd_get_squashfs_len(struct mtd_info *master,
35 struct squashfs_super_block sb;
39 err = mtd_read(master, offset, sizeof(sb), &retlen, (void *)&sb);
40 if (err || (retlen != sizeof(sb))) {
41 pr_alert("error occured while reading from \"%s\"\n",
46 if (le32_to_cpu(sb.s_magic) != SQUASHFS_MAGIC) {
47 pr_alert("no squashfs found in \"%s\"\n", master->name);
51 retlen = le64_to_cpu(sb.bytes_used);
53 pr_alert("squashfs is empty in \"%s\"\n", master->name);
57 if (offset + retlen > master->size) {
58 pr_alert("squashfs has invalid size in \"%s\"\n",
63 *squashfs_len = retlen;
66 EXPORT_SYMBOL_GPL(mtd_get_squashfs_len);
68 static ssize_t mtd_next_eb(struct mtd_info *mtd, size_t offset)
70 return mtd_rounddown_to_eb(offset, mtd) + mtd->erasesize;
73 int mtd_check_rootfs_magic(struct mtd_info *mtd, size_t offset)
79 ret = mtd_read(mtd, offset, sizeof(magic), &retlen,
80 (unsigned char *) &magic);
84 if (retlen != sizeof(magic))
87 if (le32_to_cpu(magic) != SQUASHFS_MAGIC &&
93 EXPORT_SYMBOL_GPL(mtd_check_rootfs_magic);
95 int mtd_find_rootfs_from(struct mtd_info *mtd,
103 for (offset = from; offset < limit;
104 offset = mtd_next_eb(mtd, offset)) {
105 err = mtd_check_rootfs_magic(mtd, offset);
109 *ret_offset = offset;
115 EXPORT_SYMBOL_GPL(mtd_find_rootfs_from);