2 * Copyright (C) 2012 John Crispin <blogic@openwrt.org>
3 * Copyright (C) 2015 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published
7 * by the Free Software Foundation.
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/mtd/mtd.h>
16 #include <linux/mtd/partitions.h>
17 #include <linux/byteorder/generic.h>
21 #define BRNIMAGE_NR_PARTS 2
23 #define BRNIMAGE_ALIGN_BYTES 0x400
24 #define BRNIMAGE_FOOTER_SIZE 12
26 #define BRNIMAGE_MIN_OVERHEAD (BRNIMAGE_FOOTER_SIZE)
27 #define BRNIMAGE_MAX_OVERHEAD (BRNIMAGE_ALIGN_BYTES + BRNIMAGE_FOOTER_SIZE)
29 static int mtdsplit_parse_brnimage(struct mtd_info *master,
30 struct mtd_partition **pparts,
31 struct mtd_part_parser_data *data)
33 struct mtd_partition *parts;
35 unsigned long rootfs_offset, rootfs_size, kernel_size;
39 for (rootfs_offset = 0; rootfs_offset < master->size;
40 rootfs_offset += BRNIMAGE_ALIGN_BYTES) {
41 ret = mtd_check_rootfs_magic(master, rootfs_offset, NULL);
49 if (rootfs_offset >= master->size)
52 ret = mtd_read(master, rootfs_offset - BRNIMAGE_FOOTER_SIZE, 4, &len,
60 kernel_size = le32_to_cpu(buf);
62 if (kernel_size > (rootfs_offset - BRNIMAGE_MIN_OVERHEAD))
65 if (kernel_size < (rootfs_offset - BRNIMAGE_MAX_OVERHEAD))
69 * The footer must be untouched as it contains the checksum of the
70 * original brnImage (kernel + squashfs)!
72 rootfs_size = master->size - rootfs_offset - BRNIMAGE_FOOTER_SIZE;
74 parts = kzalloc(BRNIMAGE_NR_PARTS * sizeof(*parts), GFP_KERNEL);
78 parts[0].name = KERNEL_PART_NAME;
80 parts[0].size = kernel_size;
82 parts[1].name = ROOTFS_PART_NAME;
83 parts[1].offset = rootfs_offset;
84 parts[1].size = rootfs_size;
87 return BRNIMAGE_NR_PARTS;
90 static struct mtd_part_parser mtdsplit_brnimage_parser = {
92 .name = "brnimage-fw",
93 .parse_fn = mtdsplit_parse_brnimage,
94 .type = MTD_PARSER_TYPE_FIRMWARE,
97 static int __init mtdsplit_brnimage_init(void)
99 register_mtd_parser(&mtdsplit_brnimage_parser);
104 subsys_initcall(mtdsplit_brnimage_init);