xref: /openbmc/linux/drivers/mtd/parsers/ar7part.c (revision 5a4a335a)
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 
25 struct ar7_bin_rec {
26 	unsigned int checksum;
27 	unsigned int length;
28 	unsigned int address;
29 };
30 
create_mtd_partitions(struct mtd_info * master,const struct mtd_partition ** pparts,struct mtd_part_parser_data * data)31 static 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 
120 static struct mtd_part_parser ar7_parser = {
121 	.parse_fn = create_mtd_partitions,
122 	.name = "ar7part",
123 };
124 module_mtd_part_parser(ar7_parser);
125 
126 MODULE_LICENSE("GPL");
127 MODULE_AUTHOR(	"Felix Fietkau <nbd@openwrt.org>, "
128 		"Eugene Konev <ejka@openwrt.org>");
129 MODULE_DESCRIPTION("MTD partitioning for TI AR7");
130