/*
   * 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/bcm963xx_nvram.h>

  #include <linux/bcm963xx_tag.h>

  #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>

  #define BCM963XX_CFE_BLOCK_SIZE		SZ_64K	/* always at least 64KiB */

  #define BCM963XX_CFE_MAGIC_OFFSET	0x4e0
  #define BCM963XX_CFE_VERSION_OFFSET	0x570
  #define BCM963XX_NVRAM_OFFSET		0x580

  /* Ensure strings read from flash structs are null terminated */
  #define STR_NULL_TERMINATE(x) \
  	do { char *_str = (x); _str[sizeof(x) - 1] = 0; } while (0)

  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, BCM963XX_CFE_MAGIC_OFFSET, 8, &retlen,

  		       (void *)buf);

  	buf[retlen] = 0;

  	return strncmp("CFE1CFE1", buf, 8);

  }

  static int bcm63xx_read_nvram(struct mtd_info *master,
  	struct bcm963xx_nvram *nvram)
  {
  	u32 actual_crc, expected_crc;
  	size_t retlen;
  	int ret;
  
  	/* extract nvram data */
  	ret = mtd_read(master, BCM963XX_NVRAM_OFFSET, BCM963XX_NVRAM_V5_SIZE,
  			&retlen, (void *)nvram);
  	if (ret)
  		return ret;
  
  	ret = bcm963xx_nvram_checksum(nvram, &expected_crc, &actual_crc);
  	if (ret)
  		pr_warn("nvram checksum failed, contents may be invalid (expected %08x, got %08x)
  ",
  			expected_crc, actual_crc);
  
  	if (!nvram->psi_size)
  		nvram->psi_size = BCM963XX_DEFAULT_PSI_SIZE;
  
  	return 0;
  }

  static int bcm63xx_read_image_tag(struct mtd_info *master, const char *name,
  	loff_t tag_offset, struct bcm_tag *buf)
  {
  	int ret;
  	size_t retlen;
  	u32 computed_crc;
  
  	ret = mtd_read(master, tag_offset, sizeof(*buf), &retlen, (void *)buf);
  	if (ret)
  		return ret;
  
  	if (retlen != sizeof(*buf))
  		return -EIO;
  
  	computed_crc = crc32_le(IMAGETAG_CRC_START, (u8 *)buf,
  				offsetof(struct bcm_tag, header_crc));
  	if (computed_crc == buf->header_crc) {
  		STR_NULL_TERMINATE(buf->board_id);
  		STR_NULL_TERMINATE(buf->tag_version);
  
  		pr_info("%s: CFE image tag found at 0x%llx with version %s, board type %s
  ",
  			name, tag_offset, buf->tag_version, buf->board_id);
  
  		return 0;
  	}
  
  	pr_warn("%s: CFE image tag at 0x%llx CRC invalid (expected %08x, actual %08x)
  ",
  		name, tag_offset, buf->header_crc, computed_crc);
  	return 1;
  }

  static int bcm63xx_parse_cfe_nor_partitions(struct mtd_info *master,
  	const struct mtd_partition **pparts, struct bcm963xx_nvram *nvram)

  {
  	/* CFE, NVRAM and global Linux are always present */
  	int nrparts = 3, curpart = 0;

  	struct bcm_tag *buf = NULL;

  	struct mtd_partition *parts;
  	int ret;

  	unsigned int rootfsaddr, kerneladdr, spareaddr;
  	unsigned int rootfslen, kernellen, sparelen, totallen;

  	unsigned int cfelen, nvramlen;

  	unsigned int cfe_erasesize;

  	int i;

  	bool rootfs_first = false;

  	cfe_erasesize = max_t(uint32_t, master->erasesize,

  			      BCM963XX_CFE_BLOCK_SIZE);

  
  	cfelen = cfe_erasesize;

  	nvramlen = nvram->psi_size * SZ_1K;

  	nvramlen = roundup(nvramlen, cfe_erasesize);

  	buf = vmalloc(sizeof(struct bcm_tag));

  	if (!buf)
  		return -ENOMEM;

  
  	/* Get the tag */

  	ret = bcm63xx_read_image_tag(master, "rootfs", cfelen, buf);
  	if (!ret) {

  		STR_NULL_TERMINATE(buf->flash_image_start);
  		if (kstrtouint(buf->flash_image_start, 10, &rootfsaddr) ||
  				rootfsaddr < BCM963XX_EXTENDED_SIZE) {
  			pr_err("invalid rootfs address: %*ph
  ",

  				(int)sizeof(buf->flash_image_start),

  				buf->flash_image_start);
  			goto invalid_tag;
  		}
  
  		STR_NULL_TERMINATE(buf->kernel_address);
  		if (kstrtouint(buf->kernel_address, 10, &kerneladdr) ||
  				kerneladdr < BCM963XX_EXTENDED_SIZE) {
  			pr_err("invalid kernel address: %*ph
  ",

  				(int)sizeof(buf->kernel_address),

  				buf->kernel_address);
  			goto invalid_tag;
  		}
  
  		STR_NULL_TERMINATE(buf->kernel_length);
  		if (kstrtouint(buf->kernel_length, 10, &kernellen)) {
  			pr_err("invalid kernel length: %*ph
  ",

  				(int)sizeof(buf->kernel_length),

  				buf->kernel_length);
  			goto invalid_tag;
  		}
  
  		STR_NULL_TERMINATE(buf->total_length);
  		if (kstrtouint(buf->total_length, 10, &totallen)) {
  			pr_err("invalid total length: %*ph
  ",

  				(int)sizeof(buf->total_length),

  				buf->total_length);
  			goto invalid_tag;
  		}

  		kerneladdr = kerneladdr - BCM963XX_EXTENDED_SIZE;
  		rootfsaddr = rootfsaddr - BCM963XX_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 if (ret > 0) {

  invalid_tag:

  		kernellen = 0;
  		rootfslen = 0;
  		rootfsaddr = 0;
  		spareaddr = cfelen;

  	} else {
  		goto out;

  	}

  	sparelen = master->size - spareaddr - nvramlen;

  
  	/* Determine number of partitions */

  	if (rootfslen > 0)

  		nrparts++;

  
  	if (kernellen > 0)

  		nrparts++;

  	parts = kzalloc(sizeof(*parts) * nrparts + 10 * nrparts, GFP_KERNEL);
  	if (!parts) {

  		ret = -ENOMEM;
  		goto out;

  	}
  
  	/* 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;

  	ret = 0;
  
  out:

  	vfree(buf);

  	if (ret)
  		return ret;

  	return nrparts;

  }
  
  static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
  					const struct mtd_partition **pparts,
  					struct mtd_part_parser_data *data)
  {
  	struct bcm963xx_nvram *nvram = NULL;
  	int ret;
  
  	if (bcm63xx_detect_cfe(master))
  		return -EINVAL;
  
  	nvram = vzalloc(sizeof(*nvram));
  	if (!nvram)
  		return -ENOMEM;
  
  	ret = bcm63xx_read_nvram(master, nvram);
  	if (ret)
  		goto out;
  
  	if (!mtd_type_is_nand(master))
  		ret = bcm63xx_parse_cfe_nor_partitions(master, pparts, nvram);
  	else
  		ret = -EINVAL;
  
  out:
  	vfree(nvram);
  	return ret;

  };
  
  static struct mtd_part_parser bcm63xx_cfe_parser = {

  	.parse_fn = bcm63xx_parse_cfe_partitions,
  	.name = "bcm63xxpart",
  };

  module_mtd_part_parser(bcm63xx_cfe_parser);

  
  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");