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/*
* Copyright (C) 2012 John Crispin <blogic@openwrt.org>
* Copyright (C) 2015 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/byteorder/generic.h>
#include "mtdsplit.h"
#define BRNIMAGE_NR_PARTS 2
#define BRNIMAGE_ALIGN_BYTES 0x400
#define BRNIMAGE_FOOTER_SIZE 12
#define BRNIMAGE_MIN_OVERHEAD (BRNIMAGE_FOOTER_SIZE)
#define BRNIMAGE_MAX_OVERHEAD (BRNIMAGE_ALIGN_BYTES + BRNIMAGE_FOOTER_SIZE)
static int mtdsplit_parse_brnimage(struct mtd_info *master,
struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
{
struct mtd_partition *parts;
uint32_t buf;
unsigned long rootfs_offset, rootfs_size, kernel_size;
size_t len;
int ret;
for (rootfs_offset = 0; rootfs_offset < master->size;
rootfs_offset += BRNIMAGE_ALIGN_BYTES) {
ret = mtd_check_rootfs_magic(master, rootfs_offset);
if (!ret)
break;
}
if (ret)
return ret;
if (rootfs_offset >= master->size)
return -EINVAL;
ret = mtd_read(master, rootfs_offset - BRNIMAGE_FOOTER_SIZE, 4, &len,
(void *)&buf);
if (ret)
return ret;
if (len != 4)
return -EIO;
kernel_size = le32_to_cpu(buf);
if (kernel_size > (rootfs_offset - BRNIMAGE_MIN_OVERHEAD))
return -EINVAL;
if (kernel_size < (rootfs_offset - BRNIMAGE_MAX_OVERHEAD))
return -EINVAL;
/*
* The footer must be untouched as it contains the checksum of the
* original brnImage (kernel + squashfs)!
*/
rootfs_size = master->size - rootfs_offset - BRNIMAGE_FOOTER_SIZE;
parts = kzalloc(BRNIMAGE_NR_PARTS * sizeof(*parts), GFP_KERNEL);
if (!parts)
return -ENOMEM;
parts[0].name = KERNEL_PART_NAME;
parts[0].offset = 0;
parts[0].size = kernel_size;
parts[1].name = ROOTFS_PART_NAME;
parts[1].offset = rootfs_offset;
parts[1].size = rootfs_size;
*pparts = parts;
return BRNIMAGE_NR_PARTS;
}
static struct mtd_part_parser mtdsplit_brnimage_parser = {
.owner = THIS_MODULE,
.name = "brnimage-fw",
.parse_fn = mtdsplit_parse_brnimage,
.type = MTD_PARSER_TYPE_FIRMWARE,
};
static int __init mtdsplit_brnimage_init(void)
{
register_mtd_parser(&mtdsplit_brnimage_parser);
return 0;
}
subsys_initcall(mtdsplit_brnimage_init);
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