text: /*
   *  Copyright (C) 2014 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 <asm/unaligned.h>
  
  #include "mtdsplit.h"
  
  #define LZMA_NR_PARTS		2
  #define LZMA_PROPERTIES_SIZE	5
  
  struct lzma_header {
  	u8 props[LZMA_PROPERTIES_SIZE];
  	u8 size_low[4];
  	u8 size_high[4];
  };
  
  static int mtdsplit_parse_lzma(struct mtd_info *master,
  			       const struct mtd_partition **pparts,
  			       struct mtd_part_parser_data *data)
  {
  	struct lzma_header hdr;
  	size_t hdr_len, retlen;
  	size_t rootfs_offset;
  	u32 t;
  	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;
  
  	/* verify LZMA properties */
  	if (hdr.props[0] >= (9 * 5 * 5))
  		return -EINVAL;
  
  	t = get_unaligned_le32(&hdr.props[1]);
  	if (!is_power_of_2(t))
  		return -EINVAL;
  
  	t = get_unaligned_le32(&hdr.size_high);
  	if (t)
  		return -EINVAL;
  
  	err = mtd_find_rootfs_from(master, master->erasesize, master->size,
  				   &rootfs_offset, NULL);
  	if (err)
  		return err;
  
  	parts = kzalloc(LZMA_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 LZMA_NR_PARTS;
  }
  
  static struct mtd_part_parser mtdsplit_lzma_parser = {
  	.owner = THIS_MODULE,
  	.name = "lzma-fw",
  	.parse_fn = mtdsplit_parse_lzma,
  	.type = MTD_PARSER_TYPE_FIRMWARE,
  };
  
  static int __init mtdsplit_lzma_init(void)
  {
  	register_mtd_parser(&mtdsplit_lzma_parser);
  
  	return 0;
  }
  
  subsys_initcall(mtdsplit_lzma_init);
  