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 #include <linux/of.h>
  19
  20 #include "mtdsplit.h"
  21
  22 #define EVA_NR_PARTS            2
  23 #define EVA_MAGIC               0xfeed1281
  24 #define EVA_FOOTER_SIZE         0x18
  25 #define EVA_DUMMY_SQUASHFS_SIZE 0x100
  26
  27 struct eva_image_header {
  28         uint32_t        magic;
  29         uint32_t        size;
  30 };
  31
  32 static int mtdsplit_parse_eva(struct mtd_info *master,
  33                                 const struct mtd_partition **pparts,
  34                                 struct mtd_part_parser_data *data)
  35 {
  36         struct mtd_partition *parts;
  37         struct eva_image_header hdr;
  38         size_t retlen;
  39         unsigned long kernel_size, rootfs_offset;
  40         int err;
  41
  42         err = mtd_read(master, 0, sizeof(hdr), &retlen, (void *) &hdr);
  43         if (err)
  44                 return err;
  45
  46         if (retlen != sizeof(hdr))
  47                 return -EIO;
  48
  49         if (le32_to_cpu(hdr.magic) != EVA_MAGIC)
  50                 return -EINVAL;
  51
  52         kernel_size = le32_to_cpu(hdr.size) + EVA_FOOTER_SIZE;
  53
  54         /* rootfs starts at the next 0x10000 boundary: */
  55         rootfs_offset = round_up(kernel_size, 0x10000);
  56
  57         /* skip the dummy EVA squashfs partition (with wrong endianness): */
  58         rootfs_offset += EVA_DUMMY_SQUASHFS_SIZE;
  59
  60         if (rootfs_offset >= master->size)
  61                 return -EINVAL;
  62
  63         err = mtd_check_rootfs_magic(master, rootfs_offset, NULL);
  64         if (err)
  65                 return err;
  66
  67         parts = kzalloc(EVA_NR_PARTS * sizeof(*parts), GFP_KERNEL);
  68         if (!parts)
  69                 return -ENOMEM;
  70
  71         parts[0].name = KERNEL_PART_NAME;
  72         parts[0].offset = 0;
  73         parts[0].size = kernel_size;
  74
  75         parts[1].name = ROOTFS_PART_NAME;
  76         parts[1].offset = rootfs_offset;
  77         parts[1].size = master->size - rootfs_offset;
  78
  79         *pparts = parts;
  80         return EVA_NR_PARTS;
  81 }
  82
  83 static const struct of_device_id mtdsplit_eva_of_match_table[] = {
  84         { .compatible = "avm,eva-firmware" },
  85         {},
  86 };
  87
  88 static struct mtd_part_parser mtdsplit_eva_parser = {
  89         .owner = THIS_MODULE,
  90         .name = "eva-fw",
  91         .of_match_table = mtdsplit_eva_of_match_table,
  92         .parse_fn = mtdsplit_parse_eva,
  93         .type = MTD_PARSER_TYPE_FIRMWARE,
  94 };
  95
  96 static int __init mtdsplit_eva_init(void)
  97 {
  98         register_mtd_parser(&mtdsplit_eva_parser);
  99
 100         return 0;
 101 }
 102
 103 subsys_initcall(mtdsplit_eva_init);