1/*
2 * Copyright (c) 2015 The Linux Foundation
3 * Copyright (C) 2014 Gabor Juhos <juhosg@openwrt.org>
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <linux/module.h>
19#include <linux/mtd/mtd.h>
20#include <linux/mtd/partitions.h>
21#include <linux/types.h>
22#include <linux/byteorder/generic.h>
23#include <linux/slab.h>
24#include <linux/of_fdt.h>
25
26#include "mtdsplit.h"
27
28struct fdt_header {
29	uint32_t magic;			 /* magic word FDT_MAGIC */
30	uint32_t totalsize;		 /* total size of DT block */
31	uint32_t off_dt_struct;		 /* offset to structure */
32	uint32_t off_dt_strings;	 /* offset to strings */
33	uint32_t off_mem_rsvmap;	 /* offset to memory reserve map */
34	uint32_t version;		 /* format version */
35	uint32_t last_comp_version;	 /* last compatible version */
36
37	/* version 2 fields below */
38	uint32_t boot_cpuid_phys;	 /* Which physical CPU id we're
39					    booting on */
40	/* version 3 fields below */
41	uint32_t size_dt_strings;	 /* size of the strings block */
42
43	/* version 17 fields below */
44	uint32_t size_dt_struct;	 /* size of the structure block */
45};
46
47static int
48mtdsplit_fit_parse(struct mtd_info *mtd, struct mtd_partition **pparts,
49	           struct mtd_part_parser_data *data)
50{
51	struct fdt_header hdr;
52	size_t hdr_len, retlen;
53	size_t offset;
54	size_t fit_offset, fit_size;
55	size_t rootfs_offset, rootfs_size;
56	struct mtd_partition *parts;
57	int ret;
58
59	hdr_len = sizeof(struct fdt_header);
60
61	/* Parse the MTD device & search for the FIT image location */
62	for(offset = 0; offset < mtd->size; offset += mtd->erasesize) {
63		ret = mtd_read(mtd, 0, hdr_len, &retlen, (void*) &hdr);
64		if (ret) {
65			pr_err("read error in \"%s\" at offset 0x%llx\n",
66			       mtd->name, (unsigned long long) offset);
67			return ret;
68		}
69
70		if (retlen != hdr_len) {
71			pr_err("short read in \"%s\"\n", mtd->name);
72			return -EIO;
73		}
74
75		/* Check the magic - see if this is a FIT image */
76		if (be32_to_cpu(hdr.magic) != OF_DT_HEADER) {
77			pr_debug("no valid FIT image found in \"%s\" at offset %llx\n",
78				 mtd->name, (unsigned long long) offset);
79			continue;
80		}
81
82		/* We found a FIT image. Let's keep going */
83		break;
84	}
85
86	fit_offset = offset;
87	fit_size = be32_to_cpu(hdr.totalsize);
88
89	if (fit_size == 0) {
90		pr_err("FIT image in \"%s\" at offset %llx has null size\n",
91		       mtd->name, (unsigned long long) fit_offset);
92		return -ENODEV;
93	}
94
95	/* Search for the rootfs partition after the FIT image */
96	ret = mtd_find_rootfs_from(mtd, fit_offset + fit_size, mtd->size,
97				   &rootfs_offset, NULL);
98	if (ret) {
99		pr_info("no rootfs found after FIT image in \"%s\"\n",
100			mtd->name);
101		return ret;
102	}
103
104	rootfs_size = mtd->size - rootfs_offset;
105
106	parts = kzalloc(2 * sizeof(*parts), GFP_KERNEL);
107	if (!parts)
108		return -ENOMEM;
109
110	parts[0].name = KERNEL_PART_NAME;
111	parts[0].offset = fit_offset;
112	parts[0].size = mtd_rounddown_to_eb(fit_size, mtd) + mtd->erasesize;
113
114	parts[1].name = ROOTFS_PART_NAME;
115	parts[1].offset = rootfs_offset;
116	parts[1].size = rootfs_size;
117
118	*pparts = parts;
119	return 2;
120}
121
122static struct mtd_part_parser uimage_parser = {
123	.owner = THIS_MODULE,
124	.name = "fit-fw",
125	.parse_fn = mtdsplit_fit_parse,
126	.type = MTD_PARSER_TYPE_FIRMWARE,
127};
128
129/**************************************************
130 * Init
131 **************************************************/
132
133static int __init mtdsplit_fit_init(void)
134{
135	register_mtd_parser(&uimage_parser);
136
137	return 0;
138}
139
140module_init(mtdsplit_fit_init);
141