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

    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 1.15 2005/11/07 11:14:19 gleixner 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 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\n",

                        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\n",

                ptr, ret);

        return ret;

}

static int parse_afs_partitions(struct mtd_info *mtd,

                         struct mtd_partition **pparts,

                         unsigned long origin)

{

        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, %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;

}

static struct mtd_part_parser afs_parser = {

        .owner = THIS_MODULE,

        .parse_fn = parse_afs_partitions,

        .name = "afs",

};

static int __init afs_parser_init(void)

{

        return register_mtd_parser(&afs_parser);

}

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");