/*======================================================================
  
      drivers/mtd/afs.c: ARM Flash Layout/Partitioning
  
      Copyright © 2000 ARM Limited
  
     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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  
     This is access code for flashes using ARM's flash partitioning
     standards.
  
  ======================================================================*/
  
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/string.h>
  #include <linux/init.h>
  
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/map.h>
  #include <linux/mtd/partitions.h>
  
  struct footer_struct {
  	u32 image_info_base;	/* Address of first word of ImageFooter  */
  	u32 image_start;	/* Start of area reserved by this footer */
  	u32 signature;		/* 'Magic' number proves it's a footer   */
  	u32 type;		/* Area type: ARM Image, SIB, customer   */
  	u32 checksum;		/* Just this structure                   */
  };
  
  struct image_info_struct {
  	u32 bootFlags;		/* Boot flags, compression etc.          */
  	u32 imageNumber;	/* Unique number, selects for boot etc.  */
  	u32 loadAddress;	/* Address program should be loaded to   */
  	u32 length;		/* Actual size of image                  */
  	u32 address;		/* Image is executed from here           */
  	char name[16];		/* Null terminated                       */
  	u32 headerBase;		/* Flash Address of any stripped header  */
  	u32 header_length;	/* Length of header in memory            */
  	u32 headerType;		/* AIF, RLF, s-record etc.               */
  	u32 checksum;		/* Image checksum (inc. this struct)     */
  };
  
  static u32 word_sum(void *words, int num)
  {
  	u32 *p = words;
  	u32 sum = 0;
  
  	while (num--)
  		sum += *p++;
  
  	return sum;
  }
  
  static int
  afs_read_footer(struct mtd_info *mtd, u_int *img_start, u_int *iis_start,
  		u_int off, u_int mask)
  {
  	struct footer_struct fs;
  	u_int ptr = off + mtd->erasesize - sizeof(fs);
  	size_t sz;
  	int ret;
  
  	ret = mtd_read(mtd, ptr, sizeof(fs), &sz, (u_char *)&fs);
  	if (ret >= 0 && sz != sizeof(fs))
  		ret = -EINVAL;
  
  	if (ret < 0) {
  		printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d
  ",
  			ptr, ret);
  		return ret;
  	}
  
  	ret = 1;
  
  	/*
  	 * Does it contain the magic number?
  	 */
  	if (fs.signature != 0xa0ffff9f)
  		ret = 0;
  
  	/*
  	 * Check the checksum.
  	 */
  	if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
  		ret = 0;
  
  	/*
  	 * Don't touch the SIB.
  	 */
  	if (fs.type == 2)
  		ret = 0;
  
  	*iis_start = fs.image_info_base & mask;
  	*img_start = fs.image_start & mask;
  
  	/*
  	 * Check the image info base.  This can not
  	 * be located after the footer structure.
  	 */
  	if (*iis_start >= ptr)
  		ret = 0;
  
  	/*
  	 * Check the start of this image.  The image
  	 * data can not be located after this block.
  	 */
  	if (*img_start > off)
  		ret = 0;
  
  	return ret;
  }
  
  static int
  afs_read_iis(struct mtd_info *mtd, struct image_info_struct *iis, u_int ptr)
  {
  	size_t sz;
  	int ret, i;
  
  	memset(iis, 0, sizeof(*iis));
  	ret = mtd_read(mtd, ptr, sizeof(*iis), &sz, (u_char *)iis);
  	if (ret < 0)
  		goto failed;
  
  	if (sz != sizeof(*iis)) {
  		ret = -EINVAL;
  		goto failed;
  	}
  
  	ret = 0;
  
  	/*
  	 * Validate the name - it must be NUL terminated.
  	 */
  	for (i = 0; i < sizeof(iis->name); i++)
  		if (iis->name[i] == '\0')
  			break;
  
  	if (i < sizeof(iis->name))
  		ret = 1;
  
  	return ret;
  
   failed:
  	printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d
  ",
  		ptr, ret);
  	return ret;
  }
  
  static int parse_afs_partitions(struct mtd_info *mtd,
  				struct mtd_partition **pparts,
  				struct mtd_part_parser_data *data)
  {
  	struct mtd_partition *parts;
  	u_int mask, off, idx, sz;
  	int ret = 0;
  	char *str;
  
  	/*
  	 * This is the address mask; we use this to mask off out of
  	 * range address bits.
  	 */
  	mask = mtd->size - 1;
  
  	/*
  	 * First, calculate the size of the array we need for the
  	 * partition information.  We include in this the size of
  	 * the strings.
  	 */
  	for (idx = off = sz = 0; off < mtd->size; off += mtd->erasesize) {
  		struct image_info_struct iis;
  		u_int iis_ptr, img_ptr;
  
  		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
  		if (ret < 0)
  			break;
  		if (ret == 0)
  			continue;
  
  		ret = afs_read_iis(mtd, &iis, iis_ptr);
  		if (ret < 0)
  			break;
  		if (ret == 0)
  			continue;
  
  		sz += sizeof(struct mtd_partition);
  		sz += strlen(iis.name) + 1;
  		idx += 1;
  	}
  
  	if (!sz)
  		return ret;
  
  	parts = kzalloc(sz, GFP_KERNEL);
  	if (!parts)
  		return -ENOMEM;
  
  	str = (char *)(parts + idx);
  
  	/*
  	 * Identify the partitions
  	 */
  	for (idx = off = 0; off < mtd->size; off += mtd->erasesize) {
  		struct image_info_struct iis;
  		u_int iis_ptr, img_ptr;
  
  		/* Read the footer. */
  		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
  		if (ret < 0)
  			break;
  		if (ret == 0)
  			continue;
  
  		/* Read the image info block */
  		ret = afs_read_iis(mtd, &iis, iis_ptr);
  		if (ret < 0)
  			break;
  		if (ret == 0)
  			continue;
  
  		strcpy(str, iis.name);
  
  		parts[idx].name		= str;
  		parts[idx].size		= (iis.length + mtd->erasesize - 1) & ~(mtd->erasesize - 1);
  		parts[idx].offset	= img_ptr;
  		parts[idx].mask_flags	= 0;
  
  		printk("  mtd%d: at 0x%08x, %5lluKiB, %8u, %s
  ",
  			idx, img_ptr, parts[idx].size / 1024,
  			iis.imageNumber, str);
  
  		idx += 1;
  		str = str + strlen(iis.name) + 1;
  	}
  
  	if (!idx) {
  		kfree(parts);
  		parts = NULL;
  	}
  
  	*pparts = parts;
  	return idx ? idx : ret;
  }
  
  static struct mtd_part_parser afs_parser = {
  	.owner = THIS_MODULE,
  	.parse_fn = parse_afs_partitions,
  	.name = "afs",
  };
  
  static int __init afs_parser_init(void)
  {
  	register_mtd_parser(&afs_parser);
  	return 0;
  }
  
  static void __exit afs_parser_exit(void)
  {
  	deregister_mtd_parser(&afs_parser);
  }
  
  module_init(afs_parser_init);
  module_exit(afs_parser_exit);
  
  
  MODULE_AUTHOR("ARM Ltd");
  MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
  MODULE_LICENSE("GPL");