target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_squashfs.c

   1 /*
   2  *  Copyright (C) 2013 Felix Fietkau <nbd@nbd.name>
   3  *  Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify it
   6  *  under the terms of the GNU General Public License version 2 as published
   7  *  by the Free Software Foundation.
   8  *
   9  */
  10
  11 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/slab.h>
  17 #include <linux/magic.h>
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/partitions.h>
  20 #include <linux/byteorder/generic.h>
  21
  22 #include "mtdsplit.h"
  23
  24 static int
  25 mtdsplit_parse_squashfs(struct mtd_info *master,
  26                         struct mtd_partition **pparts,
  27                         struct mtd_part_parser_data *data)
  28 {
  29         struct mtd_partition *part;
  30         struct mtd_info *parent_mtd;
  31         size_t part_offset;
  32         size_t squashfs_len;
  33         int err;
  34
  35         err = mtd_get_squashfs_len(master, 0, &squashfs_len);
  36         if (err)
  37                 return err;
  38
  39         parent_mtd = mtdpart_get_master(master);
  40         part_offset = mtdpart_get_offset(master);
  41
  42         part = kzalloc(sizeof(*part), GFP_KERNEL);
  43         if (!part) {
  44                 pr_alert("unable to allocate memory for \"%s\" partition\n",
  45                          ROOTFS_SPLIT_NAME);
  46                 return -ENOMEM;
  47         }
  48
  49         part->name = ROOTFS_SPLIT_NAME;
  50         part->offset = mtd_roundup_to_eb(part_offset + squashfs_len,
  51                                          parent_mtd) - part_offset;
  52         part->size = mtd_rounddown_to_eb(master->size - part->offset, master);
  53
  54         *pparts = part;
  55         return 1;
  56 }
  57
  58 static struct mtd_part_parser mtdsplit_squashfs_parser = {
  59         .owner = THIS_MODULE,
  60         .name = "squashfs-split",
  61         .parse_fn = mtdsplit_parse_squashfs,
  62         .type = MTD_PARSER_TYPE_ROOTFS,
  63 };
  64
  65 static int __init mtdsplit_squashfs_init(void)
  66 {
  67         register_mtd_parser(&mtdsplit_squashfs_parser);
  68
  69         return 0;
  70 }
  71
  72 subsys_initcall(mtdsplit_squashfs_init);