/*
 * $Id$
 * 
 * Copyright (C) 2007 OpenWrt.org
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * TI AR7 flash partition table.
 * Based on ar7 map by Felix Fietkau.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/bootmem.h>
#include <linux/squashfs_fs.h>

struct ar7_bin_rec {
	unsigned int checksum;
	unsigned int length;
	unsigned int address;
};

static struct mtd_partition ar7_parts[5];

static int create_mtd_partitions(struct mtd_info *master, 
				 struct mtd_partition **pparts, 
				 unsigned long origin)
{
	char sig[8];
	struct ar7_bin_rec header;
	unsigned int offset, new_offset, len;
	struct squashfs_super_block sb;
	unsigned int block_size = 0x10000, pre_size = 0x10000,
		post_size = 0, root_offset = 0xe0000; 
	unsigned int p = 3;

	printk("Parsing AR7 partition map...\n");

	ar7_parts[0].name = "loader";
	ar7_parts[0].offset = 0;
	ar7_parts[0].size = block_size;
	ar7_parts[0].mask_flags = MTD_WRITEABLE;

	ar7_parts[1].name = "config";
	ar7_parts[1].size = block_size;
	ar7_parts[1].mask_flags = 0;

	master->read(master, block_size, 8, &len, sig);
	if (strncmp(sig, "TIENV0.8", 8)) {
		ar7_parts[1].offset = master->size - block_size;
		post_size = block_size;
	} else {
		ar7_parts[1].offset = block_size;
		pre_size = block_size * 2;
	}

	ar7_parts[2].name = "linux";
	ar7_parts[2].offset = pre_size;
	ar7_parts[2].size = master->size - block_size * 2;
	ar7_parts[2].mask_flags = 0;

	offset = pre_size;
	master->read(master, offset, sizeof(header), &len, (u_char *)&header);
	if (header.checksum != 0xfeedfa42) {
		printk("Unknown magic: %08x\n", header.checksum);
	} else {
		while (header.length) {
			offset += sizeof(header) + header.length;
			master->read(master, offset, sizeof(header),
				     &len, (u_char *)&header); 
		}
		root_offset = offset + sizeof(header) + 4;
	}
	
	ar7_parts[p].name = "rootfs";
	ar7_parts[p].offset = root_offset;
	ar7_parts[p].size = master->size - root_offset - post_size;
	ar7_parts[p++].mask_flags = 0;

	master->read(master, root_offset, sizeof(sb), &len, (u_char *)&sb);
	if (sb.s_magic == SQUASHFS_MAGIC) {
		printk("Squashfs detected (size %Ld)\n", sb.bytes_used);
		new_offset = root_offset + sb.bytes_used;

		if ((new_offset % master->erasesize) > 0)
			new_offset += master->erasesize - 
				(new_offset % master->erasesize); 

		ar7_parts[p].name = "rootfs_data";
		ar7_parts[p].offset = new_offset;
		ar7_parts[p].size = master->size - new_offset - post_size;
		ar7_parts[p - 1].size -= ar7_parts[p].size;
		ar7_parts[p - 1].mask_flags |= MTD_WRITEABLE;
		ar7_parts[p++].mask_flags = 0;
	} else {
		printk("Squashfs not found. Moving rootfs partition to next erase block\n");
		if ((root_offset % master->erasesize) > 0) 
			root_offset += master->erasesize - 
				(root_offset % master->erasesize); 

		ar7_parts[p].offset = root_offset;
		ar7_parts[p].size = master->size - root_offset - post_size;
	}
	*pparts = ar7_parts;
	return p;
}

static struct mtd_part_parser ar7_parser = {
	.owner = THIS_MODULE,
	.parse_fn = create_mtd_partitions,
	.name = "ar7part",
};

static int __init ar7_parser_init(void)
{
	return register_mtd_parser(&ar7_parser);
}

module_init(ar7_parser_init);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Felix Fietkau, Eugene Konev");
MODULE_DESCRIPTION("MTD partitioning for TI AR7");