OpenWrt – Rev 4

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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 EVA_NR_PARTS            2
#define EVA_MAGIC               0xfeed1281
#define EVA_FOOTER_SIZE         0x18
#define EVA_DUMMY_SQUASHFS_SIZE 0x100

struct eva_image_header {
        uint32_t        magic;
        uint32_t        size;
};

static int mtdsplit_parse_eva(struct mtd_info *master,
                                const struct mtd_partition **pparts,
                                struct mtd_part_parser_data *data)
{
        struct mtd_partition *parts;
        struct eva_image_header hdr;
        size_t retlen;
        unsigned long kernel_size, rootfs_offset;
        int err;

        err = mtd_read(master, 0, sizeof(hdr), &retlen, (void *) &hdr);
        if (err)
                return err;

        if (retlen != sizeof(hdr))
                return -EIO;

        if (le32_to_cpu(hdr.magic) != EVA_MAGIC)
                return -EINVAL;

        kernel_size = le32_to_cpu(hdr.size) + EVA_FOOTER_SIZE;

        /* rootfs starts at the next 0x10000 boundary: */
        rootfs_offset = round_up(kernel_size, 0x10000);

        /* skip the dummy EVA squashfs partition (with wrong endianness): */
        rootfs_offset += EVA_DUMMY_SQUASHFS_SIZE;

        if (rootfs_offset >= master->size)
                return -EINVAL;

        err = mtd_check_rootfs_magic(master, rootfs_offset, NULL);
        if (err)
                return err;

        parts = kzalloc(EVA_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 = master->size - rootfs_offset;

        *pparts = parts;
        return EVA_NR_PARTS;
}

static const struct of_device_id mtdsplit_eva_of_match_table[] = {
        { .compatible = "avm,eva-firmware" },
        {},
};

static struct mtd_part_parser mtdsplit_eva_parser = {
        .owner = THIS_MODULE,
        .name = "eva-fw",
        .of_match_table = mtdsplit_eva_of_match_table,
        .parse_fn = mtdsplit_parse_eva,
        .type = MTD_PARSER_TYPE_FIRMWARE,
};

static int __init mtdsplit_eva_init(void)
{
        register_mtd_parser(&mtdsplit_eva_parser);

        return 0;
}

subsys_initcall(mtdsplit_eva_init);