1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright © 2007 Eugene Konev <ejka@openwrt.org>
4 *
5 * TI AR7 flash partition table.
6 * Based on ar7 map by Felix Fietkau <nbd@openwrt.org>
7 */
8
9#include <linux/kernel.h>
10#include <linux/slab.h>
11
12#include <linux/mtd/mtd.h>
13#include <linux/mtd/partitions.h>
14#include <linux/memblock.h>
15#include <linux/module.h>
16
17#include <uapi/linux/magic.h>
18
19#define AR7_PARTS	4
20#define ROOT_OFFSET	0xe0000
21
22#define LOADER_MAGIC1	le32_to_cpu(0xfeedfa42)
23#define LOADER_MAGIC2	le32_to_cpu(0xfeed1281)
24
25struct ar7_bin_rec {
26	unsigned int checksum;
27	unsigned int length;
28	unsigned int address;
29};
30
31static int create_mtd_partitions(struct mtd_info *master,
32				 const struct mtd_partition **pparts,
33				 struct mtd_part_parser_data *data)
34{
35	struct ar7_bin_rec header;
36	unsigned int offset;
37	size_t len;
38	unsigned int pre_size = master->erasesize, post_size = 0;
39	unsigned int root_offset = ROOT_OFFSET;
40
41	int retries = 10;
42	struct mtd_partition *ar7_parts;
43
44	ar7_parts = kcalloc(AR7_PARTS, sizeof(*ar7_parts), GFP_KERNEL);
45	if (!ar7_parts)
46		return -ENOMEM;
47	ar7_parts[0].name = "loader";
48	ar7_parts[0].offset = 0;
49	ar7_parts[0].size = master->erasesize;
50	ar7_parts[0].mask_flags = MTD_WRITEABLE;
51
52	ar7_parts[1].name = "config";
53	ar7_parts[1].offset = 0;
54	ar7_parts[1].size = master->erasesize;
55	ar7_parts[1].mask_flags = 0;
56
57	do { /* Try 10 blocks starting from master->erasesize */
58		offset = pre_size;
59		mtd_read(master, offset, sizeof(header), &len,
60			 (uint8_t *)&header);
61		if (!strncmp((char *)&header, "TIENV0.8", 8))
62			ar7_parts[1].offset = pre_size;
63		if (header.checksum == LOADER_MAGIC1)
64			break;
65		if (header.checksum == LOADER_MAGIC2)
66			break;
67		pre_size += master->erasesize;
68	} while (retries--);
69
70	pre_size = offset;
71
72	if (!ar7_parts[1].offset) {
73		ar7_parts[1].offset = master->size - master->erasesize;
74		post_size = master->erasesize;
75	}
76
77	switch (header.checksum) {
78	case LOADER_MAGIC1:
79		while (header.length) {
80			offset += sizeof(header) + header.length;
81			mtd_read(master, offset, sizeof(header), &len,
82				 (uint8_t *)&header);
83		}
84		root_offset = offset + sizeof(header) + 4;
85		break;
86	case LOADER_MAGIC2:
87		while (header.length) {
88			offset += sizeof(header) + header.length;
89			mtd_read(master, offset, sizeof(header), &len,
90				 (uint8_t *)&header);
91		}
92		root_offset = offset + sizeof(header) + 4 + 0xff;
93		root_offset &= ~(uint32_t)0xff;
94		break;
95	default:
96		printk(KERN_WARNING "Unknown magic: %08x\n", header.checksum);
97		break;
98	}
99
100	mtd_read(master, root_offset, sizeof(header), &len, (u8 *)&header);
101	if (header.checksum != SQUASHFS_MAGIC) {
102		root_offset += master->erasesize - 1;
103		root_offset &= ~(master->erasesize - 1);
104	}
105
106	ar7_parts[2].name = "linux";
107	ar7_parts[2].offset = pre_size;
108	ar7_parts[2].size = master->size - pre_size - post_size;
109	ar7_parts[2].mask_flags = 0;
110
111	ar7_parts[3].name = "rootfs";
112	ar7_parts[3].offset = root_offset;
113	ar7_parts[3].size = master->size - root_offset - post_size;
114	ar7_parts[3].mask_flags = 0;
115
116	*pparts = ar7_parts;
117	return AR7_PARTS;
118}
119
120static struct mtd_part_parser ar7_parser = {
121	.parse_fn = create_mtd_partitions,
122	.name = "ar7part",
123};
124module_mtd_part_parser(ar7_parser);
125
126MODULE_LICENSE("GPL");
127MODULE_AUTHOR(	"Felix Fietkau <nbd@openwrt.org>, "
128		"Eugene Konev <ejka@openwrt.org>");
129MODULE_DESCRIPTION("MTD partitioning for TI AR7");
130