/*
 * inftlmount.c -- INFTL mount code with extensive checks.
 *
 * Author: Greg Ungerer (gerg@snapgear.com)
 * (C) Copyright 2002-2003, Greg Ungerer (gerg@snapgear.com)
 *
 * Based heavily on the nftlmount.c code which is:
 * Author: Fabrice Bellard (fabrice.bellard@netgem.com)
 * Copyright (C) 2000 Netgem S.A.
 *
 * 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
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nftl.h>
#include <linux/mtd/inftl.h>
#include <linux/mtd/compatmac.h>

/*
 * find_boot_record: Find the INFTL Media Header and its Spare copy which
 *      contains the various device information of the INFTL partition and
 *      Bad Unit Table. Update the PUtable[] table according to the Bad
 *      Unit Table. PUtable[] is used for management of Erase Unit in
 *      other routines in inftlcore.c and inftlmount.c.
 */
static int find_boot_record(struct INFTLrecord *inftl)
{
        struct inftl_unittail h1;
        //struct inftl_oob oob;
        unsigned int i, block;
        u8 buf[SECTORSIZE];
        struct INFTLMediaHeader *mh = &inftl->MediaHdr;
        struct mtd_info *mtd = inftl->mbd.mtd;
        struct INFTLPartition *ip;
        size_t retlen;

        DEBUG(MTD_DEBUG_LEVEL3, "INFTL: find_boot_record(inftl=%p)\n", inftl);

        /*
         * Assume logical EraseSize == physical erasesize for starting the
         * scan. We'll sort it out later if we find a MediaHeader which says
         * otherwise.
         */
        inftl->EraseSize = inftl->mbd.mtd->erasesize;
        inftl->nb_blocks = (u32)inftl->mbd.mtd->size / inftl->EraseSize;

        inftl->MediaUnit = BLOCK_NIL;

        /* Search for a valid boot record */
        for (block = 0; block < inftl->nb_blocks; block++) {
                int ret;

                /*
                 * Check for BNAND header first. Then whinge if it's found
                 * but later checks fail.
                 */
                ret = mtd->read(mtd, block * inftl->EraseSize,
                                SECTORSIZE, &retlen, buf);
                /* We ignore ret in case the ECC of the MediaHeader is invalid
                   (which is apparently acceptable) */
                if (retlen != SECTORSIZE) {
                        static int warncount = 5;

                        if (warncount) {
                                printk(KERN_WARNING "INFTL: block read at 0x%x "
                                        "of mtd%d failed: %d\n",
                                        block * inftl->EraseSize,
                                        inftl->mbd.mtd->index, ret);
                                if (!--warncount)
                                        printk(KERN_WARNING "INFTL: further "
                                                "failures for this block will "
                                                "not be printed\n");
                        }
                        continue;
                }

                if (retlen < 6 || memcmp(buf, "BNAND", 6)) {
                        /* BNAND\0 not found. Continue */
                        continue;
                }

                /* To be safer with BIOS, also use erase mark as discriminant */
                if ((ret = inftl_read_oob(mtd, block * inftl->EraseSize +
                                          SECTORSIZE + 8, 8, &retlen,
                                          (char *)&h1) < 0)) {
                        printk(KERN_WARNING "INFTL: ANAND header found at "
                                "0x%x in mtd%d, but OOB data read failed "
                                "(err %d)\n", block * inftl->EraseSize,
                                inftl->mbd.mtd->index, ret);
                        continue;
                }


                /*
                 * This is the first we've seen.
                 * Copy the media header structure into place.
                 */
                memcpy(mh, buf, sizeof(struct INFTLMediaHeader));

                /* Read the spare media header at offset 4096 */
                mtd->read(mtd, block * inftl->EraseSize + 4096,
                          SECTORSIZE, &retlen, buf);
                if (retlen != SECTORSIZE) {
                        printk(KERN_WARNING "INFTL: Unable to read spare "
                               "Media Header\n");
                        return -1;
                }
                /* Check if this one is the same as the first one we found. */
                if (memcmp(mh, buf, sizeof(struct INFTLMediaHeader))) {
                        printk(KERN_WARNING "INFTL: Primary and spare Media "
                               "Headers disagree.\n");
                        return -1;
                }

                mh->NoOfBootImageBlocks = le32_to_cpu(mh->NoOfBootImageBlocks);
                mh->NoOfBinaryPartitions = le32_to_cpu(mh->NoOfBinaryPartitions);
                mh->NoOfBDTLPartitions = le32_to_cpu(mh->NoOfBDTLPartitions);
                mh->BlockMultiplierBits = le32_to_cpu(mh->BlockMultiplierBits);
                mh->FormatFlags = le32_to_cpu(mh->FormatFlags);
                mh->PercentUsed = le32_to_cpu(mh->PercentUsed);

#ifdef CONFIG_MTD_DEBUG_VERBOSE
                if (CONFIG_MTD_DEBUG_VERBOSE >= 2) {
                        printk("INFTL: Media Header ->\n"
                                "    bootRecordID          = %s\n"
                                "    NoOfBootImageBlocks   = %d\n"
                                "    NoOfBinaryPartitions  = %d\n"
                                "    NoOfBDTLPartitions    = %d\n"
                                "    BlockMultiplerBits    = %d\n"
                                "    FormatFlgs            = %d\n"
                                "    OsakVersion           = 0x%x\n"
                                "    PercentUsed           = %d\n",
                                mh->bootRecordID, mh->NoOfBootImageBlocks,
                                mh->NoOfBinaryPartitions,
                                mh->NoOfBDTLPartitions,
                                mh->BlockMultiplierBits, mh->FormatFlags,
                                mh->OsakVersion, mh->PercentUsed);
                }
#endif

                if (mh->NoOfBDTLPartitions == 0) {
                        printk(KERN_WARNING "INFTL: Media Header sanity check "
                                "failed: NoOfBDTLPartitions (%d) == 0, "
                                "must be at least 1\n", mh->NoOfBDTLPartitions);
                        return -1;
                }

                if ((mh->NoOfBDTLPartitions + mh->NoOfBinaryPartitions) > 4) {
                        printk(KERN_WARNING "INFTL: Media Header sanity check "
                                "failed: Total Partitions (%d) > 4, "
                                "BDTL=%d Binary=%d\n", mh->NoOfBDTLPartitions +
                                mh->NoOfBinaryPartitions,
                                mh->NoOfBDTLPartitions,
                                mh->NoOfBinaryPartitions);
                        return -1;
                }

                if (mh->BlockMultiplierBits > 1) {
                        printk(KERN_WARNING "INFTL: sorry, we don't support "
                                "UnitSizeFactor 0x%02x\n",
                                mh->BlockMultiplierBits);
                        return -1;
                } else if (mh->BlockMultiplierBits == 1) {
                        printk(KERN_WARNING "INFTL: support for INFTL with "
                                "UnitSizeFactor 0x%02x is experimental\n",
                                mh->BlockMultiplierBits);
                        inftl->EraseSize = inftl->mbd.mtd->erasesize <<
                                mh->BlockMultiplierBits;
                        inftl->nb_blocks = (u32)inftl->mbd.mtd->size / inftl->EraseSize;
                        block >>= mh->BlockMultiplierBits;
                }

                /* Scan the partitions */
                for (i = 0; (i < 4); i++) {
                        ip = &mh->Partitions[i];
                        ip->virtualUnits = le32_to_cpu(ip->virtualUnits);
                        ip->firstUnit = le32_to_cpu(ip->firstUnit);
                        ip->lastUnit = le32_to_cpu(ip->lastUnit);
                        ip->flags = le32_to_cpu(ip->flags);
                        ip->spareUnits = le32_to_cpu(ip->spareUnits);
                        ip->Reserved0 = le32_to_cpu(ip->Reserved0);

#ifdef CONFIG_MTD_DEBUG_VERBOSE
                        if (CONFIG_MTD_DEBUG_VERBOSE >= 2) {
                                printk("    PARTITION[%d] ->\n"
                                        "        virtualUnits    = %d\n"
                                        "        firstUnit       = %d\n"
                                        "        lastUnit        = %d\n"
                                        "        flags           = 0x%x\n"
                                        "        spareUnits      = %d\n",
                                        i, ip->virtualUnits, ip->firstUnit,
                                        ip->lastUnit, ip->flags,
                                        ip->spareUnits);
                        }
#endif

                        if (ip->Reserved0 != ip->firstUnit) {
                                struct erase_info *instr = &inftl->instr;

                                instr->mtd = inftl->mbd.mtd;

                                /*
                                 *      Most likely this is using the
                                 *      undocumented qiuck mount feature.
                                 *      We don't support that, we will need
                                 *      to erase the hidden block for full
                                 *      compatibility.
                                 */
                                instr->addr = ip->Reserved0 * inftl->EraseSize;
                                instr->len = inftl->EraseSize;
                                mtd->erase(mtd, instr);
                        }
                        if ((ip->lastUnit - ip->firstUnit + 1) < ip->virtualUnits) {
                                printk(KERN_WARNING "INFTL: Media Header "
                                        "Partition %d sanity check failed\n"
                                        "    firstUnit %d : lastUnit %d  >  "
                                        "virtualUnits %d\n", i, ip->lastUnit,
                                        ip->firstUnit, ip->Reserved0);
                                return -1;
                        }
                        if (ip->Reserved1 != 0) {
                                printk(KERN_WARNING "INFTL: Media Header "
                                        "Partition %d sanity check failed: "
                                        "Reserved1 %d != 0\n",
                                        i, ip->Reserved1);
                                return -1;
                        }

                        if (ip->flags & INFTL_BDTL)
                                break;
                }

                if (i >= 4) {
                        printk(KERN_WARNING "INFTL: Media Header Partition "
                                "sanity check failed:\n       No partition "
                                "marked as Disk Partition\n");
                        return -1;
                }

                inftl->nb_boot_blocks = ip->firstUnit;
                inftl->numvunits = ip->virtualUnits;
                if (inftl->numvunits > (inftl->nb_blocks -
                    inftl->nb_boot_blocks - 2)) {
                        printk(KERN_WARNING "INFTL: Media Header sanity check "
                                "failed:\n        numvunits (%d) > nb_blocks "
                                "(%d) - nb_boot_blocks(%d) - 2\n",
                                inftl->numvunits, inftl->nb_blocks,
                                inftl->nb_boot_blocks);
                        return -1;
                }

                inftl->mbd.size  = inftl->numvunits *
                        (inftl->EraseSize / SECTORSIZE);

                /*
                 * Block count is set to last used EUN (we won't need to keep
                 * any meta-data past that point).
                 */
                inftl->firstEUN = ip->firstUnit;
                inftl->lastEUN = ip->lastUnit;
                inftl->nb_blocks = ip->lastUnit + 1;

                /* Memory alloc */
                inftl->PUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
                if (!inftl->PUtable) {
                        printk(KERN_WARNING "INFTL: allocation of PUtable "
                                "failed (%zd bytes)\n",
                                inftl->nb_blocks * sizeof(u16));
                        return -ENOMEM;
                }

                inftl->VUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
                if (!inftl->VUtable) {
                        kfree(inftl->PUtable);
                        printk(KERN_WARNING "INFTL: allocation of VUtable "
                                "failed (%zd bytes)\n",
                                inftl->nb_blocks * sizeof(u16));
                        return -ENOMEM;
                }

                /* Mark the blocks before INFTL MediaHeader as reserved */
                for (i = 0; i < inftl->nb_boot_blocks; i++)
                        inftl->PUtable[i] = BLOCK_RESERVED;
                /* Mark all remaining blocks as potentially containing data */
                for (; i < inftl->nb_blocks; i++)
                        inftl->PUtable[i] = BLOCK_NOTEXPLORED;

                /* Mark this boot record (NFTL MediaHeader) block as reserved */
                inftl->PUtable[block] = BLOCK_RESERVED;

                /* Read Bad Erase Unit Table and modify PUtable[] accordingly */
                for (i = 0; i < inftl->nb_blocks; i++) {
                        int physblock;
                        /* If any of the physical eraseblocks are bad, don't
                           use the unit. */
                        for (physblock = 0; physblock < inftl->EraseSize; physblock += inftl->mbd.mtd->erasesize) {
                                if (inftl->mbd.mtd->block_isbad(inftl->mbd.mtd, i * inftl->EraseSize + physblock))
                                        inftl->PUtable[i] = BLOCK_RESERVED;
                        }
                }

                inftl->MediaUnit = block;
                return 0;
        }

        /* Not found. */
        return -1;
}

static int memcmpb(void *a, int c, int n)
{
        int i;
        for (i = 0; i < n; i++) {
                if (c != ((unsigned char *)a)[i])
                        return 1;
        }
        return 0;
}

/*
 * check_free_sector: check if a free sector is actually FREE,
 *      i.e. All 0xff in data and oob area.
 */
static int check_free_sectors(struct INFTLrecord *inftl, unsigned int address,
        int len, int check_oob)
{
        u8 buf[SECTORSIZE + inftl->mbd.mtd->oobsize];
        struct mtd_info *mtd = inftl->mbd.mtd;
        size_t retlen;
        int i;

        for (i = 0; i < len; i += SECTORSIZE) {
                if (mtd->read(mtd, address, SECTORSIZE, &retlen, buf))
                        return -1;
                if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
                        return -1;

                if (check_oob) {
                        if(inftl_read_oob(mtd, address, mtd->oobsize,
                                          &retlen, &buf[SECTORSIZE]) < 0)
                                return -1;
                        if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
                                return -1;
                }
                address += SECTORSIZE;
        }

        return 0;
}

/*
 * INFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase
 *               Unit and Update INFTL metadata. Each erase operation is
 *               checked with check_free_sectors.
 *
 * Return: 0 when succeed, -1 on error.
 *
 * ToDo: 1. Is it neceressary to check_free_sector after erasing ??
 */
int INFTL_formatblock(struct INFTLrecord *inftl, int block)
{
        size_t retlen;
        struct inftl_unittail uci;
        struct erase_info *instr = &inftl->instr;
        struct mtd_info *mtd = inftl->mbd.mtd;
        int physblock;

        DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_formatblock(inftl=%p,"
                "block=%d)\n", inftl, block);

        memset(instr, 0, sizeof(struct erase_info));

        /* FIXME: Shouldn't we be setting the 'discarded' flag to zero
           _first_? */

        /* Use async erase interface, test return code */
        instr->mtd = inftl->mbd.mtd;
        instr->addr = block * inftl->EraseSize;
        instr->len = inftl->mbd.mtd->erasesize;
        /* Erase one physical eraseblock at a time, even though the NAND api
           allows us to group them.  This way we if we have a failure, we can
           mark only the failed block in the bbt. */
        for (physblock = 0; physblock < inftl->EraseSize;
             physblock += instr->len, instr->addr += instr->len) {
                mtd->erase(inftl->mbd.mtd, instr);

                if (instr->state == MTD_ERASE_FAILED) {
                        printk(KERN_WARNING "INFTL: error while formatting block %d\n",
                                block);
                        goto fail;
                }

                /*
                 * Check the "freeness" of Erase Unit before updating metadata.
                 * FixMe: is this check really necessary? Since we have check
                 * the return code after the erase operation.
                 */
                if (check_free_sectors(inftl, instr->addr, instr->len, 1) != 0)
                        goto fail;
        }

        uci.EraseMark = cpu_to_le16(ERASE_MARK);
        uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
        uci.Reserved[0] = 0;
        uci.Reserved[1] = 0;
        uci.Reserved[2] = 0;
        uci.Reserved[3] = 0;
        instr->addr = block * inftl->EraseSize + SECTORSIZE * 2;
        if (inftl_write_oob(mtd, instr->addr + 8, 8, &retlen, (char *)&uci) < 0)
                goto fail;
        return 0;
fail:
        /* could not format, update the bad block table (caller is responsible
           for setting the PUtable to BLOCK_RESERVED on failure) */
        inftl->mbd.mtd->block_markbad(inftl->mbd.mtd, instr->addr);
        return -1;
}

/*
 * format_chain: Format an invalid Virtual Unit chain. It frees all the Erase
 *      Units in a Virtual Unit Chain, i.e. all the units are disconnected.
 *
 *      Since the chain is invalid then we will have to erase it from its
 *      head (normally for INFTL we go from the oldest). But if it has a
 *      loop then there is no oldest...
 */
static void format_chain(struct INFTLrecord *inftl, unsigned int first_block)
{
        unsigned int block = first_block, block1;

        printk(KERN_WARNING "INFTL: formatting chain at block %d\n",
                first_block);

        for (;;) {
                block1 = inftl->PUtable[block];

                printk(KERN_WARNING "INFTL: formatting block %d\n", block);
                if (INFTL_formatblock(inftl, block) < 0) {
                        /*
                         * Cannot format !!!! Mark it as Bad Unit,
                         */
                        inftl->PUtable[block] = BLOCK_RESERVED;
                } else {
                        inftl->PUtable[block] = BLOCK_FREE;
                }

                /* Goto next block on the chain */
                block = block1;

                if (block == BLOCK_NIL || block >= inftl->lastEUN)
                        break;
        }
}

void INFTL_dumptables(struct INFTLrecord *s)
{
        int i;

        printk("-------------------------------------------"
                "----------------------------------\n");

        printk("VUtable[%d] ->", s->nb_blocks);
        for (i = 0; i < s->nb_blocks; i++) {
                if ((i % 8) == 0)
                        printk("\n%04x: ", i);
                printk("%04x ", s->VUtable[i]);
        }

        printk("\n-------------------------------------------"
                "----------------------------------\n");

        printk("PUtable[%d-%d=%d] ->", s->firstEUN, s->lastEUN, s->nb_blocks);
        for (i = 0; i <= s->lastEUN; i++) {
                if ((i % 8) == 0)
                        printk("\n%04x: ", i);
                printk("%04x ", s->PUtable[i]);
        }

        printk("\n-------------------------------------------"
                "----------------------------------\n");

        printk("INFTL ->\n"
                "  EraseSize       = %d\n"
                "  h/s/c           = %d/%d/%d\n"
                "  numvunits       = %d\n"
                "  firstEUN        = %d\n"
                "  lastEUN         = %d\n"
                "  numfreeEUNs     = %d\n"
                "  LastFreeEUN     = %d\n"
                "  nb_blocks       = %d\n"
                "  nb_boot_blocks  = %d",
                s->EraseSize, s->heads, s->sectors, s->cylinders,
                s->numvunits, s->firstEUN, s->lastEUN, s->numfreeEUNs,
                s->LastFreeEUN, s->nb_blocks, s->nb_boot_blocks);

        printk("\n-------------------------------------------"
                "----------------------------------\n");
}

void INFTL_dumpVUchains(struct INFTLrecord *s)
{
        int logical, block, i;

        printk("-------------------------------------------"
                "----------------------------------\n");

        printk("INFTL Virtual Unit Chains:\n");
        for (logical = 0; logical < s->nb_blocks; logical++) {
                block = s->VUtable[logical];
                if (block > s->nb_blocks)
                        continue;
                printk("  LOGICAL %d --> %d ", logical, block);
                for (i = 0; i < s->nb_blocks; i++) {
                        if (s->PUtable[block] == BLOCK_NIL)
                                break;
                        block = s->PUtable[block];
                        printk("%d ", block);
                }
                printk("\n");
        }

        printk("-------------------------------------------"
                "----------------------------------\n");
}

int INFTL_mount(struct INFTLrecord *s)
{
        struct mtd_info *mtd = s->mbd.mtd;
        unsigned int block, first_block, prev_block, last_block;
        unsigned int first_logical_block, logical_block, erase_mark;
        int chain_length, do_format_chain;
        struct inftl_unithead1 h0;
        struct inftl_unittail h1;
        size_t retlen;
        int i;
        u8 *ANACtable, ANAC;

        DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_mount(inftl=%p)\n", s);

        /* Search for INFTL MediaHeader and Spare INFTL Media Header */
        if (find_boot_record(s) < 0) {
                printk(KERN_WARNING "INFTL: could not find valid boot record?\n");
                return -ENXIO;
        }

        /* Init the logical to physical table */
        for (i = 0; i < s->nb_blocks; i++)
                s->VUtable[i] = BLOCK_NIL;

        logical_block = block = BLOCK_NIL;

        /* Temporary buffer to store ANAC numbers. */
        ANACtable = kcalloc(s->nb_blocks, sizeof(u8), GFP_KERNEL);
        if (!ANACtable) {
                printk(KERN_WARNING "INFTL: allocation of ANACtable "
                                "failed (%zd bytes)\n",
                                s->nb_blocks * sizeof(u8));
                return -ENOMEM;
        }

        /*
         * First pass is to explore each physical unit, and construct the
         * virtual chains that exist (newest physical unit goes into VUtable).
         * Any block that is in any way invalid will be left in the
         * NOTEXPLORED state. Then at the end we will try to format it and
         * mark it as free.
         */
        DEBUG(MTD_DEBUG_LEVEL3, "INFTL: pass 1, explore each unit\n");
        for (first_block = s->firstEUN; first_block <= s->lastEUN; first_block++) {
                if (s->PUtable[first_block] != BLOCK_NOTEXPLORED)
                        continue;

                do_format_chain = 0;
                first_logical_block = BLOCK_NIL;
                last_block = BLOCK_NIL;
                block = first_block;

                for (chain_length = 0; ; chain_length++) {

                        if ((chain_length == 0) &&
                            (s->PUtable[block] != BLOCK_NOTEXPLORED)) {
                                /* Nothing to do here, onto next block */
                                break;
                        }

                        if (inftl_read_oob(mtd, block * s->EraseSize + 8,
                                           8, &retlen, (char *)&h0) < 0 ||
                            inftl_read_oob(mtd, block * s->EraseSize +
                                           2 * SECTORSIZE + 8, 8, &retlen,
                                           (char *)&h1) < 0) {
                                /* Should never happen? */
                                do_format_chain++;
                                break;
                        }

                        logical_block = le16_to_cpu(h0.virtualUnitNo);
                        prev_block = le16_to_cpu(h0.prevUnitNo);
                        erase_mark = le16_to_cpu((h1.EraseMark | h1.EraseMark1));
                        ANACtable[block] = h0.ANAC;

                        /* Previous block is relative to start of Partition */
                        if (prev_block < s->nb_blocks)
                                prev_block += s->firstEUN;

                        /* Already explored partial chain? */
                        if (s->PUtable[block] != BLOCK_NOTEXPLORED) {
                                /* Check if chain for this logical */
                                if (logical_block == first_logical_block) {
                                        if (last_block != BLOCK_NIL)
                                                s->PUtable[last_block] = block;
                                }
                                break;
                        }

                        /* Check for invalid block */
                        if (erase_mark != ERASE_MARK) {
                                printk(KERN_WARNING "INFTL: corrupt block %d "
                                        "in chain %d, chain length %d, erase "
                                        "mark 0x%x?\n", block, first_block,
                                        chain_length, erase_mark);
                                /*
                                 * Assume end of chain, probably incomplete
                                 * fold/erase...
                                 */
                                if (chain_length == 0)
                                        do_format_chain++;
                                break;
                        }

                        /* Check for it being free already then... */
                        if ((logical_block == BLOCK_FREE) ||
                            (logical_block == BLOCK_NIL)) {
                                s->PUtable[block] = BLOCK_FREE;
                                break;
                        }

                        /* Sanity checks on block numbers */
                        if ((logical_block >= s->nb_blocks) ||
                            ((prev_block >= s->nb_blocks) &&
                             (prev_block != BLOCK_NIL))) {
                                if (chain_length > 0) {
                                        printk(KERN_WARNING "INFTL: corrupt "
                                                "block %d in chain %d?\n",
                                                block, first_block);
                                        do_format_chain++;
                                }
                                break;
                        }

                        if (first_logical_block == BLOCK_NIL) {
                                first_logical_block = logical_block;
                        } else {
                                if (first_logical_block != logical_block) {
                                        /* Normal for folded chain... */
                                        break;
                                }
                        }

                        /*
                         * Current block is valid, so if we followed a virtual
                         * chain to get here then we can set the previous
                         * block pointer in our PUtable now. Then move onto
                         * the previous block in the chain.
                         */
                        s->PUtable[block] = BLOCK_NIL;
                        if (last_block != BLOCK_NIL)
                                s->PUtable[last_block] = block;
                        last_block = block;
                        block = prev_block;

                        /* Check for end of chain */
                        if (block == BLOCK_NIL)
                                break;

                        /* Validate next block before following it... */
                        if (block > s->lastEUN) {
                                printk(KERN_WARNING "INFTL: invalid previous "
                                        "block %d in chain %d?\n", block,
                                        first_block);
                                do_format_chain++;
                                break;
                        }
                }

                if (do_format_chain) {
                        format_chain(s, first_block);
                        continue;
                }

                /*
                 * Looks like a valid chain then. It may not really be the
                 * newest block in the chain, but it is the newest we have
                 * found so far. We might update it in later iterations of
                 * this loop if we find something newer.
                 */
                s->VUtable[first_logical_block] = first_block;
                logical_block = BLOCK_NIL;
        }

#ifdef CONFIG_MTD_DEBUG_VERBOSE
        if (CONFIG_MTD_DEBUG_VERBOSE >= 2)
                INFTL_dumptables(s);
#endif

        /*
         * Second pass, check for infinite loops in chains. These are
         * possible because we don't update the previous pointers when
         * we fold chains. No big deal, just fix them up in PUtable.
         */
        DEBUG(MTD_DEBUG_LEVEL3, "INFTL: pass 2, validate virtual chains\n");
        for (logical_block = 0; logical_block < s->numvunits; logical_block++) {
                block = s->VUtable[logical_block];
                last_block = BLOCK_NIL;

                /* Check for free/reserved/nil */
                if (block >= BLOCK_RESERVED)
                        continue;

                ANAC = ANACtable[block];
                for (i = 0; i < s->numvunits; i++) {
                        if (s->PUtable[block] == BLOCK_NIL)
                                break;
                        if (s->PUtable[block] > s->lastEUN) {
                                printk(KERN_WARNING "INFTL: invalid prev %d, "
                                        "in virtual chain %d\n",
                                        s->PUtable[block], logical_block);
                                s->PUtable[block] = BLOCK_NIL;

                        }
                        if (ANACtable[block] != ANAC) {
                                /*
                                 * Chain must point back to itself. This is ok,
                                 * but we will need adjust the tables with this
                                 * newest block and oldest block.
                                 */
                                s->VUtable[logical_block] = block;
                                s->PUtable[last_block] = BLOCK_NIL;
                                break;
                        }

                        ANAC--;
                        last_block = block;
                        block = s->PUtable[block];
                }

                if (i >= s->nb_blocks) {
                        /*
                         * Uhoo, infinite chain with valid ANACS!
                         * Format whole chain...
                         */
                        format_chain(s, first_block);
                }
        }

#ifdef CONFIG_MTD_DEBUG_VERBOSE
        if (CONFIG_MTD_DEBUG_VERBOSE >= 2)
                INFTL_dumptables(s);
        if (CONFIG_MTD_DEBUG_VERBOSE >= 2)
                INFTL_dumpVUchains(s);
#endif

        /*
         * Third pass, format unreferenced blocks and init free block count.
         */
        s->numfreeEUNs = 0;
        s->LastFreeEUN = BLOCK_NIL;

        DEBUG(MTD_DEBUG_LEVEL3, "INFTL: pass 3, format unused blocks\n");
        for (block = s->firstEUN; block <= s->lastEUN; block++) {
                if (s->PUtable[block] == BLOCK_NOTEXPLORED) {
                        printk("INFTL: unreferenced block %d, formatting it\n",
                                block);
                        if (INFTL_formatblock(s, block) < 0)
                                s->PUtable[block] = BLOCK_RESERVED;
                        else
                                s->PUtable[block] = BLOCK_FREE;
                }
                if (s->PUtable[block] == BLOCK_FREE) {
                        s->numfreeEUNs++;
                        if (s->LastFreeEUN == BLOCK_NIL)
                                s->LastFreeEUN = block;
                }
        }

        kfree(ANACtable);
        return 0;
}