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
26struct eva_image_header {
27	uint32_t	magic;
28	uint32_t	size;
29};
30
31static int mtdsplit_parse_eva(struct mtd_info *master,
32				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
82static 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
89static int __init mtdsplit_eva_init(void)
90{
91	register_mtd_parser(&mtdsplit_eva_parser);
92
93	return 0;
94}
95
96subsys_initcall(mtdsplit_eva_init);
97