103 lines
2.4 KiB
C
103 lines
2.4 KiB
C
/*
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* Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/partitions.h>
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#include <linux/byteorder/generic.h>
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#include "mtdsplit.h"
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#define SEAMA_MAGIC 0x5EA3A417
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#define SEAMA_NR_PARTS 2
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#define SEAMA_MIN_ROOTFS_OFFS 0x80000 /* 512KiB */
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struct seama_header {
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__be32 magic; /* should always be SEAMA_MAGIC. */
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__be16 reserved; /* reserved for */
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__be16 metasize; /* size of the META data */
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__be32 size; /* size of the image */
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};
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static int mtdsplit_parse_seama(struct mtd_info *master,
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struct mtd_partition **pparts,
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struct mtd_part_parser_data *data)
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{
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struct seama_header hdr;
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size_t hdr_len, retlen, kernel_size;
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size_t rootfs_offset;
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struct mtd_partition *parts;
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int err;
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hdr_len = sizeof(hdr);
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err = mtd_read(master, 0, hdr_len, &retlen, (void *) &hdr);
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if (err)
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return err;
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if (retlen != hdr_len)
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return -EIO;
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/* sanity checks */
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if (be32_to_cpu(hdr.magic) != SEAMA_MAGIC)
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return -EINVAL;
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kernel_size = hdr_len + be32_to_cpu(hdr.size) +
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be16_to_cpu(hdr.metasize);
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if (kernel_size > master->size)
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return -EINVAL;
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/* Find the rootfs after the kernel. */
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err = mtd_check_rootfs_magic(master, kernel_size);
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if (!err) {
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rootfs_offset = kernel_size;
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} else {
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/*
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* The size in the header might cover the rootfs as well.
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* Start the search from an arbitrary offset.
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*/
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err = mtd_find_rootfs_from(master, SEAMA_MIN_ROOTFS_OFFS,
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master->size, &rootfs_offset);
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if (err)
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return err;
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}
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parts = kzalloc(SEAMA_NR_PARTS * sizeof(*parts), GFP_KERNEL);
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if (!parts)
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return -ENOMEM;
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parts[0].name = KERNEL_PART_NAME;
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parts[0].offset = 0;
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parts[0].size = rootfs_offset;
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parts[1].name = ROOTFS_PART_NAME;
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parts[1].offset = rootfs_offset;
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parts[1].size = master->size - rootfs_offset;
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*pparts = parts;
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return SEAMA_NR_PARTS;
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}
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static struct mtd_part_parser mtdsplit_seama_parser = {
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.owner = THIS_MODULE,
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.name = "seama-fw",
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.parse_fn = mtdsplit_parse_seama,
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.type = MTD_PARSER_TYPE_FIRMWARE,
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};
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static int
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mtdsplit_seama_init(void)
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{
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return register_mtd_parser(&mtdsplit_seama_parser);
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}
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subsys_initcall(mtdsplit_seama_init);
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