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/*
* Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
*
* 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 SEAMA_MAGIC 0x5EA3A417
#define SEAMA_NR_PARTS 2
#define SEAMA_MIN_ROOTFS_OFFS 0x80000 /* 512KiB */
struct seama_header {
__be32 magic; /* should always be SEAMA_MAGIC. */
__be16 reserved; /* reserved for */
__be16 metasize; /* size of the META data */
__be32 size; /* size of the image */
};
static int mtdsplit_parse_seama(struct mtd_info *master,
struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
{
struct seama_header hdr;
size_t hdr_len, retlen, kernel_size;
size_t rootfs_offset;
struct mtd_partition *parts;
int err;
hdr_len = sizeof(hdr);
err = mtd_read(master, 0, hdr_len, &retlen, (void *) &hdr);
if (err)
return err;
if (retlen != hdr_len)
return -EIO;
/* sanity checks */
if (be32_to_cpu(hdr.magic) != SEAMA_MAGIC)
return -EINVAL;
kernel_size = hdr_len + be32_to_cpu(hdr.size) +
be16_to_cpu(hdr.metasize);
if (kernel_size > master->size)
return -EINVAL;
/* Find the rootfs after the kernel. */
err = mtd_check_rootfs_magic(master, kernel_size);
if (!err) {
rootfs_offset = kernel_size;
} else {
/*
* The size in the header might cover the rootfs as well.
* Start the search from an arbitrary offset.
*/
err = mtd_find_rootfs_from(master, SEAMA_MIN_ROOTFS_OFFS,
master->size, &rootfs_offset);
if (err)
return err;
}
parts = kzalloc(SEAMA_NR_PARTS * sizeof(*parts), GFP_KERNEL);
if (!parts)
return -ENOMEM;
parts[0].name = KERNEL_PART_NAME;
parts[0].offset = 0;
parts[0].size = rootfs_offset;
parts[1].name = ROOTFS_PART_NAME;
parts[1].offset = rootfs_offset;
parts[1].size = master->size - rootfs_offset;
*pparts = parts;
return SEAMA_NR_PARTS;
}
static struct mtd_part_parser mtdsplit_seama_parser = {
.owner = THIS_MODULE,
.name = "seama-fw",
.parse_fn = mtdsplit_parse_seama,
.type = MTD_PARSER_TYPE_FIRMWARE,
};
static int __init mtdsplit_seama_init(void)
{
register_mtd_parser(&mtdsplit_seama_parser);
return 0;
}
subsys_initcall(mtdsplit_seama_init);
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