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");