doc2000.c

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/*
 * Linux driver for Disk-On-Chip 2000 and Millennium
 * (c) 1999 Machine Vision Holdings, Inc.
 * (c) 1999, 2000 David Woodhouse <[email protected]>
 */

#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/sched.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/mutex.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/doc2000.h>

#define DOC_SUPPORT_2000
#define DOC_SUPPORT_2000TSOP
#define DOC_SUPPORT_MILLENNIUM

#ifdef DOC_SUPPORT_2000
#define DoC_is_2000(doc) (doc->ChipID == DOC_ChipID_Doc2k)
#else
#define DoC_is_2000(doc) (0)
#endif

#if defined(DOC_SUPPORT_2000TSOP) || defined(DOC_SUPPORT_MILLENNIUM)
#define DoC_is_Millennium(doc) (doc->ChipID == DOC_ChipID_DocMil)
#else
#define DoC_is_Millennium(doc) (0)
#endif

/* #define ECC_DEBUG */

/* I have no idea why some DoC chips can not use memcpy_from|to_io().
 * This may be due to the different revisions of the ASIC controller built-in or
 * simplily a QA/Bug issue. Who knows ?? If you have trouble, please uncomment
 * this:
 #undef USE_MEMCPY
*/

static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
            size_t *retlen, u_char *buf);
static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
             size_t *retlen, const u_char *buf);
static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
            struct mtd_oob_ops *ops);
static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
             struct mtd_oob_ops *ops);
static int doc_write_oob_nolock(struct mtd_info *mtd, loff_t ofs, size_t len,
             size_t *retlen, const u_char *buf);
static int doc_erase (struct mtd_info *mtd, struct erase_info *instr);

static struct mtd_info *doc2klist = NULL;

/* Perform the required delay cycles by reading from the appropriate register */
static void DoC_Delay(struct DiskOnChip *doc, unsigned short cycles)
{
    volatile char dummy;
    int i;

    for (i = 0; i < cycles; i++) {
        if (DoC_is_Millennium(doc))
            dummy = ReadDOC(doc->virtadr, NOP);
        else
            dummy = ReadDOC(doc->virtadr, DOCStatus);
    }

}

/* DOC_WaitReady: Wait for RDY line to be asserted by the flash chip */
static int _DoC_WaitReady(struct DiskOnChip *doc)
{
    void __iomem *docptr = doc->virtadr;
    unsigned long timeo = jiffies + (HZ * 10);

    pr_debug("_DoC_WaitReady called for out-of-line wait\n");

    /* Out-of-line routine to wait for chip response */
    while (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B)) {
        /* issue 2 read from NOP register after reading from CDSNControl register
        see Software Requirement 11.4 item 2. */
        DoC_Delay(doc, 2);

        if (time_after(jiffies, timeo)) {
            pr_debug("_DoC_WaitReady timed out.\n");
            return -EIO;
        }
        udelay(1);
        cond_resched();
    }

    return 0;
}

static inline int DoC_WaitReady(struct DiskOnChip *doc)
{
    void __iomem *docptr = doc->virtadr;

    /* This is inline, to optimise the common case, where it's ready instantly */
    int ret = 0;

    /* 4 read form NOP register should be issued in prior to the read from CDSNControl
       see Software Requirement 11.4 item 2. */
    DoC_Delay(doc, 4);

    if (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B))
        /* Call the out-of-line routine to wait */
        ret = _DoC_WaitReady(doc);

    /* issue 2 read from NOP register after reading from CDSNControl register
       see Software Requirement 11.4 item 2. */
    DoC_Delay(doc, 2);

    return ret;
}

/* DoC_Command: Send a flash command to the flash chip through the CDSN Slow IO register to
   bypass the internal pipeline. Each of 4 delay cycles (read from the NOP register) is
   required after writing to CDSN Control register, see Software Requirement 11.4 item 3. */

static int DoC_Command(struct DiskOnChip *doc, unsigned char command,
                  unsigned char xtraflags)
{
    void __iomem *docptr = doc->virtadr;

    if (DoC_is_2000(doc))
        xtraflags |= CDSN_CTRL_FLASH_IO;

    /* Assert the CLE (Command Latch Enable) line to the flash chip */
    WriteDOC(xtraflags | CDSN_CTRL_CLE | CDSN_CTRL_CE, docptr, CDSNControl);
    DoC_Delay(doc, 4);  /* Software requirement 11.4.3 for Millennium */

    if (DoC_is_Millennium(doc))
        WriteDOC(command, docptr, CDSNSlowIO);

    /* Send the command */
    WriteDOC_(command, docptr, doc->ioreg);
    if (DoC_is_Millennium(doc))
        WriteDOC(command, docptr, WritePipeTerm);

    /* Lower the CLE line */
    WriteDOC(xtraflags | CDSN_CTRL_CE, docptr, CDSNControl);
    DoC_Delay(doc, 4);  /* Software requirement 11.4.3 for Millennium */

    /* Wait for the chip to respond - Software requirement 11.4.1 (extended for any command) */
    return DoC_WaitReady(doc);
}

/* DoC_Address: Set the current address for the flash chip through the CDSN Slow IO register to
   bypass the internal pipeline. Each of 4 delay cycles (read from the NOP register) is
   required after writing to CDSN Control register, see Software Requirement 11.4 item 3. */

static int DoC_Address(struct DiskOnChip *doc, int numbytes, unsigned long ofs,
               unsigned char xtraflags1, unsigned char xtraflags2)
{
    int i;
    void __iomem *docptr = doc->virtadr;

    if (DoC_is_2000(doc))
        xtraflags1 |= CDSN_CTRL_FLASH_IO;

    /* Assert the ALE (Address Latch Enable) line to the flash chip */
    WriteDOC(xtraflags1 | CDSN_CTRL_ALE | CDSN_CTRL_CE, docptr, CDSNControl);

    DoC_Delay(doc, 4);  /* Software requirement 11.4.3 for Millennium */

    /* Send the address */
    /* Devices with 256-byte page are addressed as:
       Column (bits 0-7), Page (bits 8-15, 16-23, 24-31)
       * there is no device on the market with page256
       and more than 24 bits.
       Devices with 512-byte page are addressed as:
       Column (bits 0-7), Page (bits 9-16, 17-24, 25-31)
       * 25-31 is sent only if the chip support it.
       * bit 8 changes the read command to be sent
       (NAND_CMD_READ0 or NAND_CMD_READ1).
     */

    if (numbytes == ADDR_COLUMN || numbytes == ADDR_COLUMN_PAGE) {
        if (DoC_is_Millennium(doc))
            WriteDOC(ofs & 0xff, docptr, CDSNSlowIO);
        WriteDOC_(ofs & 0xff, docptr, doc->ioreg);
    }

    if (doc->page256) {
        ofs = ofs >> 8;
    } else {
        ofs = ofs >> 9;
    }

    if (numbytes == ADDR_PAGE || numbytes == ADDR_COLUMN_PAGE) {
        for (i = 0; i < doc->pageadrlen; i++, ofs = ofs >> 8) {
            if (DoC_is_Millennium(doc))
                WriteDOC(ofs & 0xff, docptr, CDSNSlowIO);
            WriteDOC_(ofs & 0xff, docptr, doc->ioreg);
        }
    }

    if (DoC_is_Millennium(doc))
        WriteDOC(ofs & 0xff, docptr, WritePipeTerm);

    DoC_Delay(doc, 2);  /* Needed for some slow flash chips. mf. */

    /* FIXME: The SlowIO's for millennium could be replaced by
       a single WritePipeTerm here. mf. */

    /* Lower the ALE line */
    WriteDOC(xtraflags1 | xtraflags2 | CDSN_CTRL_CE, docptr,
         CDSNControl);

    DoC_Delay(doc, 4);  /* Software requirement 11.4.3 for Millennium */

    /* Wait for the chip to respond - Software requirement 11.4.1 */
    return DoC_WaitReady(doc);
}

/* Read a buffer from DoC, taking care of Millennium odditys */
static void DoC_ReadBuf(struct DiskOnChip *doc, u_char * buf, int len)
{
    volatile int dummy;
    int modulus = 0xffff;
    void __iomem *docptr = doc->virtadr;
    int i;

    if (len <= 0)
        return;

    if (DoC_is_Millennium(doc)) {
        /* Read the data via the internal pipeline through CDSN IO register,
           see Pipelined Read Operations 11.3 */
        dummy = ReadDOC(docptr, ReadPipeInit);

        /* Millennium should use the LastDataRead register - Pipeline Reads */
        len--;

        /* This is needed for correctly ECC calculation */
        modulus = 0xff;
    }

    for (i = 0; i < len; i++)
        buf[i] = ReadDOC_(docptr, doc->ioreg + (i & modulus));

    if (DoC_is_Millennium(doc)) {
        buf[i] = ReadDOC(docptr, LastDataRead);
    }
}

/* Write a buffer to DoC, taking care of Millennium odditys */
static void DoC_WriteBuf(struct DiskOnChip *doc, const u_char * buf, int len)
{
    void __iomem *docptr = doc->virtadr;
    int i;

    if (len <= 0)
        return;

    for (i = 0; i < len; i++)
        WriteDOC_(buf[i], docptr, doc->ioreg + i);

    if (DoC_is_Millennium(doc)) {
        WriteDOC(0x00, docptr, WritePipeTerm);
    }
}


/* DoC_SelectChip: Select a given flash chip within the current floor */

static inline int DoC_SelectChip(struct DiskOnChip *doc, int chip)
{
    void __iomem *docptr = doc->virtadr;

    /* Software requirement 11.4.4 before writing DeviceSelect */
    /* Deassert the CE line to eliminate glitches on the FCE# outputs */
    WriteDOC(CDSN_CTRL_WP, docptr, CDSNControl);
    DoC_Delay(doc, 4);  /* Software requirement 11.4.3 for Millennium */

    /* Select the individual flash chip requested */
    WriteDOC(chip, docptr, CDSNDeviceSelect);
    DoC_Delay(doc, 4);

    /* Reassert the CE line */
    WriteDOC(CDSN_CTRL_CE | CDSN_CTRL_FLASH_IO | CDSN_CTRL_WP, docptr,
         CDSNControl);
    DoC_Delay(doc, 4);  /* Software requirement 11.4.3 for Millennium */

    /* Wait for it to be ready */
    return DoC_WaitReady(doc);
}

/* DoC_SelectFloor: Select a given floor (bank of flash chips) */

static inline int DoC_SelectFloor(struct DiskOnChip *doc, int floor)
{
    void __iomem *docptr = doc->virtadr;

    /* Select the floor (bank) of chips required */
    WriteDOC(floor, docptr, FloorSelect);

    /* Wait for the chip to be ready */
    return DoC_WaitReady(doc);
}

/* DoC_IdentChip: Identify a given NAND chip given {floor,chip} */

static int DoC_IdentChip(struct DiskOnChip *doc, int floor, int chip)
{
    int mfr, id, i, j;
    volatile char dummy;

    /* Page in the required floor/chip */
    DoC_SelectFloor(doc, floor);
    DoC_SelectChip(doc, chip);

    /* Reset the chip */
    if (DoC_Command(doc, NAND_CMD_RESET, CDSN_CTRL_WP)) {
        pr_debug("DoC_Command (reset) for %d,%d returned true\n",
              floor, chip);
        return 0;
    }


    /* Read the NAND chip ID: 1. Send ReadID command */
    if (DoC_Command(doc, NAND_CMD_READID, CDSN_CTRL_WP)) {
        pr_debug("DoC_Command (ReadID) for %d,%d returned true\n",
              floor, chip);
        return 0;
    }

    /* Read the NAND chip ID: 2. Send address byte zero */
    DoC_Address(doc, ADDR_COLUMN, 0, CDSN_CTRL_WP, 0);

    /* Read the manufacturer and device id codes from the device */

    if (DoC_is_Millennium(doc)) {
        DoC_Delay(doc, 2);
        dummy = ReadDOC(doc->virtadr, ReadPipeInit);
        mfr = ReadDOC(doc->virtadr, LastDataRead);

        DoC_Delay(doc, 2);
        dummy = ReadDOC(doc->virtadr, ReadPipeInit);
        id = ReadDOC(doc->virtadr, LastDataRead);
    } else {
        /* CDSN Slow IO register see Software Req 11.4 item 5. */
        dummy = ReadDOC(doc->virtadr, CDSNSlowIO);
        DoC_Delay(doc, 2);
        mfr = ReadDOC_(doc->virtadr, doc->ioreg);

        /* CDSN Slow IO register see Software Req 11.4 item 5. */
        dummy = ReadDOC(doc->virtadr, CDSNSlowIO);
        DoC_Delay(doc, 2);
        id = ReadDOC_(doc->virtadr, doc->ioreg);
    }

    /* No response - return failure */
    if (mfr == 0xff || mfr == 0)
        return 0;

    /* Check it's the same as the first chip we identified.
     * M-Systems say that any given DiskOnChip device should only
     * contain _one_ type of flash part, although that's not a
     * hardware restriction. */
    if (doc->mfr) {
        if (doc->mfr == mfr && doc->id == id)
            return 1;   /* This is the same as the first */
        else
            printk(KERN_WARNING
                   "Flash chip at floor %d, chip %d is different:\n",
                   floor, chip);
    }

    /* Print and store the manufacturer and ID codes. */
    for (i = 0; nand_flash_ids[i].name != NULL; i++) {
        if (id == nand_flash_ids[i].id) {
            /* Try to identify manufacturer */
            for (j = 0; nand_manuf_ids[j].id != 0x0; j++) {
                if (nand_manuf_ids[j].id == mfr)
                    break;
            }
            printk(KERN_INFO
                   "Flash chip found: Manufacturer ID: %2.2X, "
                   "Chip ID: %2.2X (%s:%s)\n", mfr, id,
                   nand_manuf_ids[j].name, nand_flash_ids[i].name);
            if (!doc->mfr) {
                doc->mfr = mfr;
                doc->id = id;
                doc->chipshift =
                    ffs((nand_flash_ids[i].chipsize << 20)) - 1;
                doc->page256 = (nand_flash_ids[i].pagesize == 256) ? 1 : 0;
                doc->pageadrlen = doc->chipshift > 25 ? 3 : 2;
                doc->erasesize =
                    nand_flash_ids[i].erasesize;
                return 1;
            }
            return 0;
        }
    }


    /* We haven't fully identified the chip. Print as much as we know. */
    printk(KERN_WARNING "Unknown flash chip found: %2.2X %2.2X\n",
           id, mfr);

    printk(KERN_WARNING "Please report to [email protected]\n");
    return 0;
}

/* DoC_ScanChips: Find all NAND chips present in a DiskOnChip, and identify them */

static void DoC_ScanChips(struct DiskOnChip *this, int maxchips)
{
    int floor, chip;
    int numchips[MAX_FLOORS];
    int ret = 1;

    this->numchips = 0;
    this->mfr = 0;
    this->id = 0;

    /* For each floor, find the number of valid chips it contains */
    for (floor = 0; floor < MAX_FLOORS; floor++) {
        ret = 1;
        numchips[floor] = 0;
        for (chip = 0; chip < maxchips && ret != 0; chip++) {

            ret = DoC_IdentChip(this, floor, chip);
            if (ret) {
                numchips[floor]++;
                this->numchips++;
            }
        }
    }

    /* If there are none at all that we recognise, bail */
    if (!this->numchips) {
        printk(KERN_NOTICE "No flash chips recognised.\n");
        return;
    }

    /* Allocate an array to hold the information for each chip */
    this->chips = kmalloc(sizeof(struct Nand) * this->numchips, GFP_KERNEL);
    if (!this->chips) {
        printk(KERN_NOTICE "No memory for allocating chip info structures\n");
        return;
    }

    ret = 0;

    /* Fill out the chip array with {floor, chipno} for each
     * detected chip in the device. */
    for (floor = 0; floor < MAX_FLOORS; floor++) {
        for (chip = 0; chip < numchips[floor]; chip++) {
            this->chips[ret].floor = floor;
            this->chips[ret].chip = chip;
            this->chips[ret].curadr = 0;
            this->chips[ret].curmode = 0x50;
            ret++;
        }
    }

    /* Calculate and print the total size of the device */
    this->totlen = this->numchips * (1 << this->chipshift);

    printk(KERN_INFO "%d flash chips found. Total DiskOnChip size: %ld MiB\n",
           this->numchips, this->totlen >> 20);
}

static int DoC2k_is_alias(struct DiskOnChip *doc1, struct DiskOnChip *doc2)
{
    int tmp1, tmp2, retval;
    if (doc1->physadr == doc2->physadr)
        return 1;

    /* Use the alias resolution register which was set aside for this
     * purpose. If it's value is the same on both chips, they might
     * be the same chip, and we write to one and check for a change in
     * the other. It's unclear if this register is usuable in the
     * DoC 2000 (it's in the Millennium docs), but it seems to work. */
    tmp1 = ReadDOC(doc1->virtadr, AliasResolution);
    tmp2 = ReadDOC(doc2->virtadr, AliasResolution);
    if (tmp1 != tmp2)
        return 0;

    WriteDOC((tmp1 + 1) % 0xff, doc1->virtadr, AliasResolution);
    tmp2 = ReadDOC(doc2->virtadr, AliasResolution);
    if (tmp2 == (tmp1 + 1) % 0xff)
        retval = 1;
    else
        retval = 0;

    /* Restore register contents.  May not be necessary, but do it just to
     * be safe. */
    WriteDOC(tmp1, doc1->virtadr, AliasResolution);

    return retval;
}

/* This routine is found from the docprobe code by symbol_get(),
 * which will bump the use count of this module. */
void DoC2k_init(struct mtd_info *mtd)
{
    struct DiskOnChip *this = mtd->priv;
    struct DiskOnChip *old = NULL;
    int maxchips;

    /* We must avoid being called twice for the same device. */

    if (doc2klist)
        old = doc2klist->priv;

    while (old) {
        if (DoC2k_is_alias(old, this)) {
            printk(KERN_NOTICE
                   "Ignoring DiskOnChip 2000 at 0x%lX - already configured\n",
                   this->physadr);
            iounmap(this->virtadr);
            kfree(mtd);
            return;
        }
        if (old->nextdoc)
            old = old->nextdoc->priv;
        else
            old = NULL;
    }


    switch (this->ChipID) {
    case DOC_ChipID_Doc2kTSOP:
        mtd->name = "DiskOnChip 2000 TSOP";
        this->ioreg = DoC_Mil_CDSN_IO;
        /* Pretend it's a Millennium */
        this->ChipID = DOC_ChipID_DocMil;
        maxchips = MAX_CHIPS;
        break;
    case DOC_ChipID_Doc2k:
        mtd->name = "DiskOnChip 2000";
        this->ioreg = DoC_2k_CDSN_IO;
        maxchips = MAX_CHIPS;
        break;
    case DOC_ChipID_DocMil:
        mtd->name = "DiskOnChip Millennium";
        this->ioreg = DoC_Mil_CDSN_IO;
        maxchips = MAX_CHIPS_MIL;
        break;
    default:
        printk("Unknown ChipID 0x%02x\n", this->ChipID);
        kfree(mtd);
        iounmap(this->virtadr);
        return;
    }

    printk(KERN_NOTICE "%s found at address 0x%lX\n", mtd->name,
           this->physadr);

    mtd->type = MTD_NANDFLASH;
    mtd->flags = MTD_CAP_NANDFLASH;
    mtd->writebufsize = mtd->writesize = 512;
    mtd->oobsize = 16;
    mtd->ecc_strength = 2;
    mtd->owner = THIS_MODULE;
    mtd->_erase = doc_erase;
    mtd->_read = doc_read;
    mtd->_write = doc_write;
    mtd->_read_oob = doc_read_oob;
    mtd->_write_oob = doc_write_oob;
    this->curfloor = -1;
    this->curchip = -1;
    mutex_init(&this->lock);

    /* Ident all the chips present. */
    DoC_ScanChips(this, maxchips);

    if (!this->totlen) {
        kfree(mtd);
        iounmap(this->virtadr);
    } else {
        this->nextdoc = doc2klist;
        doc2klist = mtd;
        mtd->size = this->totlen;
        mtd->erasesize = this->erasesize;
        mtd_device_register(mtd, NULL, 0);
        return;
    }
}
EXPORT_SYMBOL_GPL(DoC2k_init);

static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
            size_t * retlen, u_char * buf)
{
    struct DiskOnChip *this = mtd->priv;
    void __iomem *docptr = this->virtadr;
    struct Nand *mychip;
    unsigned char syndrome[6], eccbuf[6];
    volatile char dummy;
    int i, len256 = 0, ret=0;
    size_t left = len;

    mutex_lock(&this->lock);
    while (left) {
        len = left;

        /* Don't allow a single read to cross a 512-byte block boundary */
        if (from + len > ((from | 0x1ff) + 1))
            len = ((from | 0x1ff) + 1) - from;

        /* The ECC will not be calculated correctly if less than 512 is read */
        if (len != 0x200)
            printk(KERN_WARNING
                   "ECC needs a full sector read (adr: %lx size %lx)\n",
                   (long) from, (long) len);

        /* printk("DoC_Read (adr: %lx size %lx)\n", (long) from, (long) len); */


        /* Find the chip which is to be used and select it */
        mychip = &this->chips[from >> (this->chipshift)];

        if (this->curfloor != mychip->floor) {
            DoC_SelectFloor(this, mychip->floor);
            DoC_SelectChip(this, mychip->chip);
        } else if (this->curchip != mychip->chip) {
            DoC_SelectChip(this, mychip->chip);
        }

        this->curfloor = mychip->floor;
        this->curchip = mychip->chip;

        DoC_Command(this,
                (!this->page256
                 && (from & 0x100)) ? NAND_CMD_READ1 : NAND_CMD_READ0,
                CDSN_CTRL_WP);
        DoC_Address(this, ADDR_COLUMN_PAGE, from, CDSN_CTRL_WP,
                CDSN_CTRL_ECC_IO);

        /* Prime the ECC engine */
        WriteDOC(DOC_ECC_RESET, docptr, ECCConf);
        WriteDOC(DOC_ECC_EN, docptr, ECCConf);

        /* treat crossing 256-byte sector for 2M x 8bits devices */
        if (this->page256 && from + len > (from | 0xff) + 1) {
            len256 = (from | 0xff) + 1 - from;
            DoC_ReadBuf(this, buf, len256);

            DoC_Command(this, NAND_CMD_READ0, CDSN_CTRL_WP);
            DoC_Address(this, ADDR_COLUMN_PAGE, from + len256,
                    CDSN_CTRL_WP, CDSN_CTRL_ECC_IO);
        }

        DoC_ReadBuf(this, &buf[len256], len - len256);

        /* Let the caller know we completed it */
        *retlen += len;

        /* Read the ECC data through the DiskOnChip ECC logic */
        /* Note: this will work even with 2M x 8bit devices as   */
        /*       they have 8 bytes of OOB per 256 page. mf.      */
        DoC_ReadBuf(this, eccbuf, 6);

        /* Flush the pipeline */
        if (DoC_is_Millennium(this)) {
            dummy = ReadDOC(docptr, ECCConf);
            dummy = ReadDOC(docptr, ECCConf);
            i = ReadDOC(docptr, ECCConf);
        } else {
            dummy = ReadDOC(docptr, 2k_ECCStatus);
            dummy = ReadDOC(docptr, 2k_ECCStatus);
            i = ReadDOC(docptr, 2k_ECCStatus);
        }

        /* Check the ECC Status */
        if (i & 0x80) {
            int nb_errors;
            /* There was an ECC error */
#ifdef ECC_DEBUG
            printk(KERN_ERR "DiskOnChip ECC Error: Read at %lx\n", (long)from);
#endif
            /* Read the ECC syndrome through the DiskOnChip ECC
               logic.  These syndrome will be all ZERO when there
               is no error */
            for (i = 0; i < 6; i++) {
                syndrome[i] =
                    ReadDOC(docptr, ECCSyndrome0 + i);
            }
            nb_errors = doc_decode_ecc(buf, syndrome);

#ifdef ECC_DEBUG
            printk(KERN_ERR "Errors corrected: %x\n", nb_errors);
#endif
            if (nb_errors < 0) {
                /* We return error, but have actually done the
                   read. Not that this can be told to
                   user-space, via sys_read(), but at least
                   MTD-aware stuff can know about it by
                   checking *retlen */
                ret = -EIO;
            }
        }

#ifdef PSYCHO_DEBUG
        printk(KERN_DEBUG "ECC DATA at %lxB: %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
               (long)from, eccbuf[0], eccbuf[1], eccbuf[2],
               eccbuf[3], eccbuf[4], eccbuf[5]);
#endif

        /* disable the ECC engine */
        WriteDOC(DOC_ECC_DIS, docptr , ECCConf);

        /* according to 11.4.1, we need to wait for the busy line
             * drop if we read to the end of the page.  */
        if(0 == ((from + len) & 0x1ff))
        {
            DoC_WaitReady(this);
        }

        from += len;
        left -= len;
        buf += len;
    }

    mutex_unlock(&this->lock);

    return ret;
}

static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
             size_t * retlen, const u_char * buf)
{
    struct DiskOnChip *this = mtd->priv;
    int di; /* Yes, DI is a hangover from when I was disassembling the binary driver */
    void __iomem *docptr = this->virtadr;
    unsigned char eccbuf[6];
    volatile char dummy;
    int len256 = 0;
    struct Nand *mychip;
    size_t left = len;
    int status;

    mutex_lock(&this->lock);
    while (left) {
        len = left;

        /* Don't allow a single write to cross a 512-byte block boundary */
        if (to + len > ((to | 0x1ff) + 1))
            len = ((to | 0x1ff) + 1) - to;

        /* The ECC will not be calculated correctly if less than 512 is written */
/* DBB-
        if (len != 0x200 && eccbuf)
            printk(KERN_WARNING
                   "ECC needs a full sector write (adr: %lx size %lx)\n",
                   (long) to, (long) len);
   -DBB */

        /* printk("DoC_Write (adr: %lx size %lx)\n", (long) to, (long) len); */

        /* Find the chip which is to be used and select it */
        mychip = &this->chips[to >> (this->chipshift)];

        if (this->curfloor != mychip->floor) {
            DoC_SelectFloor(this, mychip->floor);
            DoC_SelectChip(this, mychip->chip);
        } else if (this->curchip != mychip->chip) {
            DoC_SelectChip(this, mychip->chip);
        }

        this->curfloor = mychip->floor;
        this->curchip = mychip->chip;

        /* Set device to main plane of flash */
        DoC_Command(this, NAND_CMD_RESET, CDSN_CTRL_WP);
        DoC_Command(this,
                (!this->page256
                 && (to & 0x100)) ? NAND_CMD_READ1 : NAND_CMD_READ0,
                CDSN_CTRL_WP);

        DoC_Command(this, NAND_CMD_SEQIN, 0);
        DoC_Address(this, ADDR_COLUMN_PAGE, to, 0, CDSN_CTRL_ECC_IO);

        /* Prime the ECC engine */
        WriteDOC(DOC_ECC_RESET, docptr, ECCConf);
        WriteDOC(DOC_ECC_EN | DOC_ECC_RW, docptr, ECCConf);

        /* treat crossing 256-byte sector for 2M x 8bits devices */
        if (this->page256 && to + len > (to | 0xff) + 1) {
            len256 = (to | 0xff) + 1 - to;
            DoC_WriteBuf(this, buf, len256);

            DoC_Command(this, NAND_CMD_PAGEPROG, 0);

            DoC_Command(this, NAND_CMD_STATUS, CDSN_CTRL_WP);
            /* There's an implicit DoC_WaitReady() in DoC_Command */

            dummy = ReadDOC(docptr, CDSNSlowIO);
            DoC_Delay(this, 2);

            if (ReadDOC_(docptr, this->ioreg) & 1) {
                printk(KERN_ERR "Error programming flash\n");
                /* Error in programming */
                *retlen = 0;
                mutex_unlock(&this->lock);
                return -EIO;
            }

            DoC_Command(this, NAND_CMD_SEQIN, 0);
            DoC_Address(this, ADDR_COLUMN_PAGE, to + len256, 0,
                    CDSN_CTRL_ECC_IO);
        }

        DoC_WriteBuf(this, &buf[len256], len - len256);

        WriteDOC(CDSN_CTRL_ECC_IO | CDSN_CTRL_CE, docptr, CDSNControl);

        if (DoC_is_Millennium(this)) {
            WriteDOC(0, docptr, NOP);
            WriteDOC(0, docptr, NOP);
            WriteDOC(0, docptr, NOP);
        } else {
            WriteDOC_(0, docptr, this->ioreg);
            WriteDOC_(0, docptr, this->ioreg);
            WriteDOC_(0, docptr, this->ioreg);
        }

        WriteDOC(CDSN_CTRL_ECC_IO | CDSN_CTRL_FLASH_IO | CDSN_CTRL_CE, docptr,
             CDSNControl);

        /* Read the ECC data through the DiskOnChip ECC logic */
        for (di = 0; di < 6; di++) {
            eccbuf[di] = ReadDOC(docptr, ECCSyndrome0 + di);
        }

        /* Reset the ECC engine */
        WriteDOC(DOC_ECC_DIS, docptr, ECCConf);

#ifdef PSYCHO_DEBUG
        printk
            ("OOB data at %lx is %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
             (long) to, eccbuf[0], eccbuf[1], eccbuf[2], eccbuf[3],
             eccbuf[4], eccbuf[5]);
#endif
        DoC_Command(this, NAND_CMD_PAGEPROG, 0);

        DoC_Command(this, NAND_CMD_STATUS, CDSN_CTRL_WP);
        /* There's an implicit DoC_WaitReady() in DoC_Command */

        if (DoC_is_Millennium(this)) {
            ReadDOC(docptr, ReadPipeInit);
            status = ReadDOC(docptr, LastDataRead);
        } else {
            dummy = ReadDOC(docptr, CDSNSlowIO);
            DoC_Delay(this, 2);
            status = ReadDOC_(docptr, this->ioreg);
        }

        if (status & 1) {
            printk(KERN_ERR "Error programming flash\n");
            /* Error in programming */
            *retlen = 0;
            mutex_unlock(&this->lock);
            return -EIO;
        }

        /* Let the caller know we completed it */
        *retlen += len;

        {
            unsigned char x[8];
            size_t dummy;
            int ret;

            /* Write the ECC data to flash */
            for (di=0; di<6; di++)
                x[di] = eccbuf[di];

            x[6]=0x55;
            x[7]=0x55;

            ret = doc_write_oob_nolock(mtd, to, 8, &dummy, x);
            if (ret) {
                mutex_unlock(&this->lock);
                return ret;
            }
        }

        to += len;
        left -= len;
        buf += len;
    }

    mutex_unlock(&this->lock);
    return 0;
}

static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
            struct mtd_oob_ops *ops)
{
    struct DiskOnChip *this = mtd->priv;
    int len256 = 0, ret;
    struct Nand *mychip;
    uint8_t *buf = ops->oobbuf;
    size_t len = ops->len;

    BUG_ON(ops->mode != MTD_OPS_PLACE_OOB);

    ofs += ops->ooboffs;

    mutex_lock(&this->lock);

    mychip = &this->chips[ofs >> this->chipshift];

    if (this->curfloor != mychip->floor) {
        DoC_SelectFloor(this, mychip->floor);
        DoC_SelectChip(this, mychip->chip);
    } else if (this->curchip != mychip->chip) {
        DoC_SelectChip(this, mychip->chip);
    }
    this->curfloor = mychip->floor;
    this->curchip = mychip->chip;

    /* update address for 2M x 8bit devices. OOB starts on the second */
    /* page to maintain compatibility with doc_read_ecc. */
    if (this->page256) {
        if (!(ofs & 0x8))
            ofs += 0x100;
        else
            ofs -= 0x8;
    }

    DoC_Command(this, NAND_CMD_READOOB, CDSN_CTRL_WP);
    DoC_Address(this, ADDR_COLUMN_PAGE, ofs, CDSN_CTRL_WP, 0);

    /* treat crossing 8-byte OOB data for 2M x 8bit devices */
    /* Note: datasheet says it should automaticaly wrap to the */
    /*       next OOB block, but it didn't work here. mf.      */
    if (this->page256 && ofs + len > (ofs | 0x7) + 1) {
        len256 = (ofs | 0x7) + 1 - ofs;
        DoC_ReadBuf(this, buf, len256);

        DoC_Command(this, NAND_CMD_READOOB, CDSN_CTRL_WP);
        DoC_Address(this, ADDR_COLUMN_PAGE, ofs & (~0x1ff),
                CDSN_CTRL_WP, 0);
    }

    DoC_ReadBuf(this, &buf[len256], len - len256);

    ops->retlen = len;
    /* Reading the full OOB data drops us off of the end of the page,
         * causing the flash device to go into busy mode, so we need
         * to wait until ready 11.4.1 and Toshiba TC58256FT docs */

    ret = DoC_WaitReady(this);

    mutex_unlock(&this->lock);
    return ret;

}

static int doc_write_oob_nolock(struct mtd_info *mtd, loff_t ofs, size_t len,
                size_t * retlen, const u_char * buf)
{
    struct DiskOnChip *this = mtd->priv;
    int len256 = 0;
    void __iomem *docptr = this->virtadr;
    struct Nand *mychip = &this->chips[ofs >> this->chipshift];
    volatile int dummy;
    int status;

    //      printk("doc_write_oob(%lx, %d): %2.2X %2.2X %2.2X %2.2X ... %2.2X %2.2X .. %2.2X %2.2X\n",(long)ofs, len,
    //   buf[0], buf[1], buf[2], buf[3], buf[8], buf[9], buf[14],buf[15]);

    /* Find the chip which is to be used and select it */
    if (this->curfloor != mychip->floor) {
        DoC_SelectFloor(this, mychip->floor);
        DoC_SelectChip(this, mychip->chip);
    } else if (this->curchip != mychip->chip) {
        DoC_SelectChip(this, mychip->chip);
    }
    this->curfloor = mychip->floor;
    this->curchip = mychip->chip;

    /* disable the ECC engine */
    WriteDOC (DOC_ECC_RESET, docptr, ECCConf);
    WriteDOC (DOC_ECC_DIS, docptr, ECCConf);

    /* Reset the chip, see Software Requirement 11.4 item 1. */
    DoC_Command(this, NAND_CMD_RESET, CDSN_CTRL_WP);

    /* issue the Read2 command to set the pointer to the Spare Data Area. */
    DoC_Command(this, NAND_CMD_READOOB, CDSN_CTRL_WP);

    /* update address for 2M x 8bit devices. OOB starts on the second */
    /* page to maintain compatibility with doc_read_ecc. */
    if (this->page256) {
        if (!(ofs & 0x8))
            ofs += 0x100;
        else
            ofs -= 0x8;
    }

    /* issue the Serial Data In command to initial the Page Program process */
    DoC_Command(this, NAND_CMD_SEQIN, 0);
    DoC_Address(this, ADDR_COLUMN_PAGE, ofs, 0, 0);

    /* treat crossing 8-byte OOB data for 2M x 8bit devices */
    /* Note: datasheet says it should automaticaly wrap to the */
    /*       next OOB block, but it didn't work here. mf.      */
    if (this->page256 && ofs + len > (ofs | 0x7) + 1) {
        len256 = (ofs | 0x7) + 1 - ofs;
        DoC_WriteBuf(this, buf, len256);

        DoC_Command(this, NAND_CMD_PAGEPROG, 0);
        DoC_Command(this, NAND_CMD_STATUS, 0);
        /* DoC_WaitReady() is implicit in DoC_Command */

        if (DoC_is_Millennium(this)) {
            ReadDOC(docptr, ReadPipeInit);
            status = ReadDOC(docptr, LastDataRead);
        } else {
            dummy = ReadDOC(docptr, CDSNSlowIO);
            DoC_Delay(this, 2);
            status = ReadDOC_(docptr, this->ioreg);
        }

        if (status & 1) {
            printk(KERN_ERR "Error programming oob data\n");
            /* There was an error */
            *retlen = 0;
            return -EIO;
        }
        DoC_Command(this, NAND_CMD_SEQIN, 0);
        DoC_Address(this, ADDR_COLUMN_PAGE, ofs & (~0x1ff), 0, 0);
    }

    DoC_WriteBuf(this, &buf[len256], len - len256);

    DoC_Command(this, NAND_CMD_PAGEPROG, 0);
    DoC_Command(this, NAND_CMD_STATUS, 0);
    /* DoC_WaitReady() is implicit in DoC_Command */

    if (DoC_is_Millennium(this)) {
        ReadDOC(docptr, ReadPipeInit);
        status = ReadDOC(docptr, LastDataRead);
    } else {
        dummy = ReadDOC(docptr, CDSNSlowIO);
        DoC_Delay(this, 2);
        status = ReadDOC_(docptr, this->ioreg);
    }

    if (status & 1) {
        printk(KERN_ERR "Error programming oob data\n");
        /* There was an error */
        *retlen = 0;
        return -EIO;
    }

    *retlen = len;
    return 0;

}

static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
             struct mtd_oob_ops *ops)
{
    struct DiskOnChip *this = mtd->priv;
    int ret;

    BUG_ON(ops->mode != MTD_OPS_PLACE_OOB);

    mutex_lock(&this->lock);
    ret = doc_write_oob_nolock(mtd, ofs + ops->ooboffs, ops->len,
                   &ops->retlen, ops->oobbuf);

    mutex_unlock(&this->lock);
    return ret;
}

static int doc_erase(struct mtd_info *mtd, struct erase_info *instr)
{
    struct DiskOnChip *this = mtd->priv;
    __u32 ofs = instr->addr;
    __u32 len = instr->len;
    volatile int dummy;
    void __iomem *docptr = this->virtadr;
    struct Nand *mychip;
    int status;

    mutex_lock(&this->lock);

    if (ofs & (mtd->erasesize-1) || len & (mtd->erasesize-1)) {
        mutex_unlock(&this->lock);
        return -EINVAL;
    }

    instr->state = MTD_ERASING;

    /* FIXME: Do this in the background. Use timers or schedule_task() */
    while(len) {
        mychip = &this->chips[ofs >> this->chipshift];

        if (this->curfloor != mychip->floor) {
            DoC_SelectFloor(this, mychip->floor);
            DoC_SelectChip(this, mychip->chip);
        } else if (this->curchip != mychip->chip) {
            DoC_SelectChip(this, mychip->chip);
        }
        this->curfloor = mychip->floor;
        this->curchip = mychip->chip;

        DoC_Command(this, NAND_CMD_ERASE1, 0);
        DoC_Address(this, ADDR_PAGE, ofs, 0, 0);
        DoC_Command(this, NAND_CMD_ERASE2, 0);

        DoC_Command(this, NAND_CMD_STATUS, CDSN_CTRL_WP);

        if (DoC_is_Millennium(this)) {
            ReadDOC(docptr, ReadPipeInit);
            status = ReadDOC(docptr, LastDataRead);
        } else {
            dummy = ReadDOC(docptr, CDSNSlowIO);
            DoC_Delay(this, 2);
            status = ReadDOC_(docptr, this->ioreg);
        }

        if (status & 1) {
            printk(KERN_ERR "Error erasing at 0x%x\n", ofs);
            /* There was an error */
            instr->state = MTD_ERASE_FAILED;
            goto callback;
        }
        ofs += mtd->erasesize;
        len -= mtd->erasesize;
    }
    instr->state = MTD_ERASE_DONE;

 callback:
    mtd_erase_callback(instr);

    mutex_unlock(&this->lock);
    return 0;
}


/****************************************************************************
 *
 * Module stuff
 *
 ****************************************************************************/

static void __exit cleanup_doc2000(void)
{
    struct mtd_info *mtd;
    struct DiskOnChip *this;

    while ((mtd = doc2klist)) {
        this = mtd->priv;
        doc2klist = this->nextdoc;

        mtd_device_unregister(mtd);

        iounmap(this->virtadr);
        kfree(this->chips);
        kfree(mtd);
    }
}

module_exit(cleanup_doc2000);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <[email protected]> et al.");
MODULE_DESCRIPTION("MTD driver for DiskOnChip 2000 and Millennium");