/*
   * Copyright © 2007 Eugene Konev <ejka@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 <nbd@openwrt.org>
   *
   */
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/partitions.h>
  #include <linux/bootmem.h>
  #include <linux/magic.h>

  #include <linux/module.h>

  
  #define AR7_PARTS	4
  #define ROOT_OFFSET	0xe0000
  
  #define LOADER_MAGIC1	le32_to_cpu(0xfeedfa42)
  #define LOADER_MAGIC2	le32_to_cpu(0xfeed1281)

  #ifndef SQUASHFS_MAGIC
  #define SQUASHFS_MAGIC	0x73717368
  #endif

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

  static int create_mtd_partitions(struct mtd_info *master,
  				 struct mtd_partition **pparts,

  				 struct mtd_part_parser_data *data)

  {
  	struct ar7_bin_rec header;

  	unsigned int offset;
  	size_t len;

  	unsigned int pre_size = master->erasesize, post_size = 0;
  	unsigned int root_offset = ROOT_OFFSET;
  
  	int retries = 10;

  	struct mtd_partition *ar7_parts;

  	ar7_parts = kzalloc(sizeof(*ar7_parts) * AR7_PARTS, GFP_KERNEL);
  	if (!ar7_parts)
  		return -ENOMEM;

  	ar7_parts[0].name = "loader";
  	ar7_parts[0].offset = 0;
  	ar7_parts[0].size = master->erasesize;
  	ar7_parts[0].mask_flags = MTD_WRITEABLE;
  
  	ar7_parts[1].name = "config";
  	ar7_parts[1].offset = 0;
  	ar7_parts[1].size = master->erasesize;
  	ar7_parts[1].mask_flags = 0;
  
  	do { /* Try 10 blocks starting from master->erasesize */
  		offset = pre_size;

  		mtd_read(master, offset, sizeof(header), &len,
  			 (uint8_t *)&header);

  		if (!strncmp((char *)&header, "TIENV0.8", 8))
  			ar7_parts[1].offset = pre_size;
  		if (header.checksum == LOADER_MAGIC1)
  			break;
  		if (header.checksum == LOADER_MAGIC2)
  			break;
  		pre_size += master->erasesize;
  	} while (retries--);
  
  	pre_size = offset;
  
  	if (!ar7_parts[1].offset) {
  		ar7_parts[1].offset = master->size - master->erasesize;
  		post_size = master->erasesize;
  	}
  
  	switch (header.checksum) {
  	case LOADER_MAGIC1:
  		while (header.length) {
  			offset += sizeof(header) + header.length;

  			mtd_read(master, offset, sizeof(header), &len,
  				 (uint8_t *)&header);

  		}
  		root_offset = offset + sizeof(header) + 4;
  		break;
  	case LOADER_MAGIC2:
  		while (header.length) {
  			offset += sizeof(header) + header.length;

  			mtd_read(master, offset, sizeof(header), &len,
  				 (uint8_t *)&header);

  		}
  		root_offset = offset + sizeof(header) + 4 + 0xff;

  		root_offset &= ~(uint32_t)0xff;

  		break;
  	default:
  		printk(KERN_WARNING "Unknown magic: %08x
  ", header.checksum);
  		break;
  	}

  	mtd_read(master, root_offset, sizeof(header), &len, (u8 *)&header);

  	if (header.checksum != SQUASHFS_MAGIC) {
  		root_offset += master->erasesize - 1;
  		root_offset &= ~(master->erasesize - 1);
  	}
  
  	ar7_parts[2].name = "linux";
  	ar7_parts[2].offset = pre_size;
  	ar7_parts[2].size = master->size - pre_size - post_size;
  	ar7_parts[2].mask_flags = 0;
  
  	ar7_parts[3].name = "rootfs";
  	ar7_parts[3].offset = root_offset;
  	ar7_parts[3].size = master->size - root_offset - post_size;
  	ar7_parts[3].mask_flags = 0;
  
  	*pparts = ar7_parts;
  	return AR7_PARTS;
  }
  
  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 <nbd@openwrt.org>, "
  		"Eugene Konev <ejka@openwrt.org>");
  MODULE_DESCRIPTION("MTD partitioning for TI AR7");