/*
   * BCM63XX CFE image tag parser
   *
   * Copyright © 2006-2008  Florian Fainelli <florian@openwrt.org>
   *			  Mike Albon <malbon@openwrt.org>
   * Copyright © 2009-2010  Daniel Dickinson <openwrt@cshore.neomailbox.net>
   * Copyright © 2011-2013  Jonas Gorski <jonas.gorski@gmail.com>
   *
   * 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
   *
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/crc32.h>
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/sizes.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/partitions.h>
  
  #include <asm/mach-bcm63xx/bcm63xx_nvram.h>
  #include <asm/mach-bcm63xx/bcm963xx_tag.h>
  #include <asm/mach-bcm63xx/board_bcm963xx.h>
  
  #define BCM63XX_EXTENDED_SIZE	0xBFC00000	/* Extended flash address */
  
  #define BCM63XX_CFE_BLOCK_SIZE	SZ_64K		/* always at least 64KiB */
  
  #define BCM63XX_CFE_MAGIC_OFFSET 0x4e0
  
  static int bcm63xx_detect_cfe(struct mtd_info *master)
  {
  	char buf[9];
  	int ret;
  	size_t retlen;
  
  	ret = mtd_read(master, BCM963XX_CFE_VERSION_OFFSET, 5, &retlen,
  		       (void *)buf);
  	buf[retlen] = 0;
  
  	if (ret)
  		return ret;
  
  	if (strncmp("cfe-v", buf, 5) == 0)
  		return 0;
  
  	/* very old CFE's do not have the cfe-v string, so check for magic */
  	ret = mtd_read(master, BCM63XX_CFE_MAGIC_OFFSET, 8, &retlen,
  		       (void *)buf);
  	buf[retlen] = 0;
  
  	return strncmp("CFE1CFE1", buf, 8);
  }
  
  static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
  					struct mtd_partition **pparts,
  					struct mtd_part_parser_data *data)
  {
  	/* CFE, NVRAM and global Linux are always present */
  	int nrparts = 3, curpart = 0;
  	struct bcm_tag *buf;
  	struct mtd_partition *parts;
  	int ret;
  	size_t retlen;
  	unsigned int rootfsaddr, kerneladdr, spareaddr;
  	unsigned int rootfslen, kernellen, sparelen, totallen;
  	unsigned int cfelen, nvramlen;
  	unsigned int cfe_erasesize;
  	int i;
  	u32 computed_crc;
  	bool rootfs_first = false;
  
  	if (bcm63xx_detect_cfe(master))
  		return -EINVAL;
  
  	cfe_erasesize = max_t(uint32_t, master->erasesize,
  			      BCM63XX_CFE_BLOCK_SIZE);
  
  	cfelen = cfe_erasesize;
  	nvramlen = bcm63xx_nvram_get_psi_size() * SZ_1K;
  	nvramlen = roundup(nvramlen, cfe_erasesize);
  
  	/* Allocate memory for buffer */
  	buf = vmalloc(sizeof(struct bcm_tag));
  	if (!buf)
  		return -ENOMEM;
  
  	/* Get the tag */
  	ret = mtd_read(master, cfelen, sizeof(struct bcm_tag), &retlen,
  		       (void *)buf);
  
  	if (retlen != sizeof(struct bcm_tag)) {
  		vfree(buf);
  		return -EIO;
  	}
  
  	computed_crc = crc32_le(IMAGETAG_CRC_START, (u8 *)buf,
  				offsetof(struct bcm_tag, header_crc));
  	if (computed_crc == buf->header_crc) {
  		char *boardid = &(buf->board_id[0]);
  		char *tagversion = &(buf->tag_version[0]);
  
  		sscanf(buf->flash_image_start, "%u", &rootfsaddr);
  		sscanf(buf->kernel_address, "%u", &kerneladdr);
  		sscanf(buf->kernel_length, "%u", &kernellen);
  		sscanf(buf->total_length, "%u", &totallen);
  
  		pr_info("CFE boot tag found with version %s and board type %s
  ",
  			tagversion, boardid);
  
  		kerneladdr = kerneladdr - BCM63XX_EXTENDED_SIZE;
  		rootfsaddr = rootfsaddr - BCM63XX_EXTENDED_SIZE;
  		spareaddr = roundup(totallen, master->erasesize) + cfelen;
  
  		if (rootfsaddr < kerneladdr) {
  			/* default Broadcom layout */
  			rootfslen = kerneladdr - rootfsaddr;
  			rootfs_first = true;
  		} else {
  			/* OpenWrt layout */
  			rootfsaddr = kerneladdr + kernellen;
  			rootfslen = spareaddr - rootfsaddr;
  		}
  	} else {
  		pr_warn("CFE boot tag CRC invalid (expected %08x, actual %08x)
  ",
  			buf->header_crc, computed_crc);
  		kernellen = 0;
  		rootfslen = 0;
  		rootfsaddr = 0;
  		spareaddr = cfelen;
  	}
  	sparelen = master->size - spareaddr - nvramlen;
  
  	/* Determine number of partitions */
  	if (rootfslen > 0)
  		nrparts++;
  
  	if (kernellen > 0)
  		nrparts++;
  
  	/* Ask kernel for more memory */
  	parts = kzalloc(sizeof(*parts) * nrparts + 10 * nrparts, GFP_KERNEL);
  	if (!parts) {
  		vfree(buf);
  		return -ENOMEM;
  	}
  
  	/* Start building partition list */
  	parts[curpart].name = "CFE";
  	parts[curpart].offset = 0;
  	parts[curpart].size = cfelen;
  	curpart++;
  
  	if (kernellen > 0) {
  		int kernelpart = curpart;
  
  		if (rootfslen > 0 && rootfs_first)
  			kernelpart++;
  		parts[kernelpart].name = "kernel";
  		parts[kernelpart].offset = kerneladdr;
  		parts[kernelpart].size = kernellen;
  		curpart++;
  	}
  
  	if (rootfslen > 0) {
  		int rootfspart = curpart;
  
  		if (kernellen > 0 && rootfs_first)
  			rootfspart--;
  		parts[rootfspart].name = "rootfs";
  		parts[rootfspart].offset = rootfsaddr;
  		parts[rootfspart].size = rootfslen;
  		if (sparelen > 0  && !rootfs_first)
  			parts[rootfspart].size += sparelen;
  		curpart++;
  	}
  
  	parts[curpart].name = "nvram";
  	parts[curpart].offset = master->size - nvramlen;
  	parts[curpart].size = nvramlen;
  	curpart++;
  
  	/* Global partition "linux" to make easy firmware upgrade */
  	parts[curpart].name = "linux";
  	parts[curpart].offset = cfelen;
  	parts[curpart].size = master->size - cfelen - nvramlen;
  
  	for (i = 0; i < nrparts; i++)
  		pr_info("Partition %d is %s offset %llx and length %llx
  ", i,
  			parts[i].name, parts[i].offset,	parts[i].size);
  
  	pr_info("Spare partition is offset %x and length %x
  ",	spareaddr,
  		sparelen);
  
  	*pparts = parts;
  	vfree(buf);
  
  	return nrparts;
  };
  
  static struct mtd_part_parser bcm63xx_cfe_parser = {
  	.owner = THIS_MODULE,
  	.parse_fn = bcm63xx_parse_cfe_partitions,
  	.name = "bcm63xxpart",
  };
  
  static int __init bcm63xx_cfe_parser_init(void)
  {
  	register_mtd_parser(&bcm63xx_cfe_parser);
  	return 0;
  }
  
  static void __exit bcm63xx_cfe_parser_exit(void)
  {
  	deregister_mtd_parser(&bcm63xx_cfe_parser);
  }
  
  module_init(bcm63xx_cfe_parser_init);
  module_exit(bcm63xx_cfe_parser_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Daniel Dickinson <openwrt@cshore.neomailbox.net>");
  MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
  MODULE_AUTHOR("Mike Albon <malbon@openwrt.org>");
  MODULE_AUTHOR("Jonas Gorski <jonas.gorski@gmail.com");
  MODULE_DESCRIPTION("MTD partitioning for BCM63XX CFE bootloaders");