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

   1 /*
   2  *  Copyright (C) 2012 John Crispin <blogic@openwrt.org>
   3  *  Copyright (C) 2015 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
   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 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/mtd/partitions.h>
  17 #include <linux/byteorder/generic.h>
  18
  19 #include "mtdsplit.h"
  20
  21 #define EVA_NR_PARTS            2
  22 #define EVA_MAGIC               0xfeed1281
  23 #define EVA_FOOTER_SIZE         0x18
  24 #define EVA_DUMMY_SQUASHFS_SIZE 0x100
  25
  26 struct eva_image_header {
  27         uint32_t        magic;
  28         uint32_t        size;
  29 };
  30
  31 static int mtdsplit_parse_eva(struct mtd_info *master,
  32                                 const struct mtd_partition **pparts,
  33                                 struct mtd_part_parser_data *data)
  34 {
  35         struct mtd_partition *parts;
  36         struct eva_image_header hdr;
  37         size_t retlen;
  38         unsigned long kernel_size, rootfs_offset;
  39         int err;
  40
  41         err = mtd_read(master, 0, sizeof(hdr), &retlen, (void *) &hdr);
  42         if (err)
  43                 return err;
  44
  45         if (retlen != sizeof(hdr))
  46                 return -EIO;
  47
  48         if (le32_to_cpu(hdr.magic) != EVA_MAGIC)
  49                 return -EINVAL;
  50
  51         kernel_size = le32_to_cpu(hdr.size) + EVA_FOOTER_SIZE;
  52
  53         /* rootfs starts at the next 0x10000 boundary: */
  54         rootfs_offset = round_up(kernel_size, 0x10000);
  55
  56         /* skip the dummy EVA squashfs partition (with wrong endianness): */
  57         rootfs_offset += EVA_DUMMY_SQUASHFS_SIZE;
  58
  59         if (rootfs_offset >= master->size)
  60                 return -EINVAL;
  61
  62         err = mtd_check_rootfs_magic(master, rootfs_offset, NULL);
  63         if (err)
  64                 return err;
  65
  66         parts = kzalloc(EVA_NR_PARTS * sizeof(*parts), GFP_KERNEL);
  67         if (!parts)
  68                 return -ENOMEM;
  69
  70         parts[0].name = KERNEL_PART_NAME;
  71         parts[0].offset = 0;
  72         parts[0].size = kernel_size;
  73
  74         parts[1].name = ROOTFS_PART_NAME;
  75         parts[1].offset = rootfs_offset;
  76         parts[1].size = master->size - rootfs_offset;
  77
  78         *pparts = parts;
  79         return EVA_NR_PARTS;
  80 }
  81
  82 static struct mtd_part_parser mtdsplit_eva_parser = {
  83         .owner = THIS_MODULE,
  84         .name = "eva-fw",
  85         .parse_fn = mtdsplit_parse_eva,
  86         .type = MTD_PARSER_TYPE_FIRMWARE,
  87 };
  88
  89 static int __init mtdsplit_eva_init(void)
  90 {
  91         register_mtd_parser(&mtdsplit_eva_parser);
  92
  93         return 0;
  94 }
  95
  96 subsys_initcall(mtdsplit_eva_init);