/*======================================================================

    drivers/mtd/afs.c: ARM Flash Layout/Partitioning
  
    Copyright (C) 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.

   $Id: afs.c,v 1.8 2002/05/04 08:49:09 rmk Exp $

======================================================================*/

#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 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\n",
                        ptr, ret);
                return ret;
        }

        /*
         * Does it contain the magic number?
         */
        if (fs.signature != 0xa0ffff9f)
                ret = 1;

        /*
         * Don't touch the SIB.
         */
        if (fs.type == 2)
                ret = 1;

        *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 = 1;

        /*
         * Check the start of this image.  The image
         * data can not be located after this block.
         */
        if (*img_start > off)
                ret = 1;

        return ret;
}

static int
afs_read_iis(struct mtd_info *mtd, struct image_info_struct *iis, u_int ptr)
{
        size_t sz;
        int ret;

        memset(iis, 0, sizeof(*iis));
        ret = mtd->read(mtd, ptr, sizeof(*iis), &sz, (u_char *) iis);
        if (ret >= 0 && sz != sizeof(*iis))
                ret = -EINVAL;
        if (ret < 0)
                printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
                        ptr, ret);

        return ret;
}

int parse_afs_partitions(struct mtd_info *mtd, struct mtd_partition **pparts)
{
        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 == 1)
                        continue;

                ret = afs_read_iis(mtd, &iis, iis_ptr);
                if (ret < 0)
                        break;

                sz += sizeof(struct mtd_partition);
                sz += strlen(iis.name) + 1;
                idx += 1;
        }

        if (!sz)
                return ret;

        parts = kmalloc(sz, GFP_KERNEL);
        if (!parts)
                return -ENOMEM;

        memset(parts, 0, sz);
        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, size;

                /* Read the footer. */
                ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
                if (ret < 0)
                        break;
                if (ret == 1)
                        continue;

                /* Read the image info block */
                ret = afs_read_iis(mtd, &iis, iis_ptr);
                if (ret < 0)
                        break;

                strcpy(str, iis.name);
                size = mtd->erasesize + off - img_ptr;

                /*
                 * In order to support JFFS2 partitions on this layout,
                 * we must lie to MTD about the real size of JFFS2
                 * partitions; this ensures that the AFS flash footer
                 * won't be erased by JFFS2.  Please ensure that your
                 * JFFS2 partitions are given image numbers between
                 * 1000 and 2000 inclusive.
                 */
                if (iis.imageNumber >= 1000 && iis.imageNumber < 2000)
                        size -= mtd->erasesize;

                parts[idx].name         = str;
                parts[idx].size         = size;
                parts[idx].offset       = img_ptr;
                parts[idx].mask_flags   = 0;

                printk("  mtd%d: at 0x%08x, %5dKB, %8u, %s\n",
                        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;
}

EXPORT_SYMBOL(parse_afs_partitions);

MODULE_AUTHOR("ARM Ltd");
MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
MODULE_LICENSE("GPL");