OpenWrt – Rev 4

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/*
 *  Copyright (C) 2013 Felix Fietkau <nbd@nbd.name>
 *  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.
 *
 */

#define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/magic.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/byteorder/generic.h>

#include "mtdsplit.h"

static int
mtdsplit_parse_squashfs(struct mtd_info *master,
                        const struct mtd_partition **pparts,
                        struct mtd_part_parser_data *data)
{
        struct mtd_partition *part;
        struct mtd_info *parent_mtd;
        size_t part_offset;
        size_t squashfs_len;
        int err;

        err = mtd_get_squashfs_len(master, 0, &squashfs_len);
        if (err)
                return err;

        parent_mtd = mtdpart_get_master(master);
        part_offset = mtdpart_get_offset(master);

        part = kzalloc(sizeof(*part), GFP_KERNEL);
        if (!part) {
                pr_alert("unable to allocate memory for \"%s\" partition\n",
                         ROOTFS_SPLIT_NAME);
                return -ENOMEM;
        }

        part->name = ROOTFS_SPLIT_NAME;
        part->offset = mtd_roundup_to_eb(part_offset + squashfs_len,
                                         parent_mtd) - part_offset;
        part->size = mtd_rounddown_to_eb(master->size - part->offset, master);

        *pparts = part;
        return 1;
}

static struct mtd_part_parser mtdsplit_squashfs_parser = {
        .owner = THIS_MODULE,
        .name = "squashfs-split",
        .parse_fn = mtdsplit_parse_squashfs,
        .type = MTD_PARSER_TYPE_ROOTFS,
};

static int __init mtdsplit_squashfs_init(void)
{
        register_mtd_parser(&mtdsplit_squashfs_parser);

        return 0;
}

subsys_initcall(mtdsplit_squashfs_init);