[MTD] NAND Modularize read function

[sfrench/cifs-2.6.git] / drivers / mtd / nand / nand_base.c

/*
 *  drivers/mtd/nand.c
 *
 *  Overview:
 *   This is the generic MTD driver for NAND flash devices. It should be
 *   capable of working with almost all NAND chips currently available.
 *   Basic support for AG-AND chips is provided.
 *
 *      Additional technical information is available on
 *      http://www.linux-mtd.infradead.org/tech/nand.html
 *
 *  Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)
 *                2002-2006 Thomas Gleixner (tglx@linutronix.de)
 *
 *  Credits:
 *      David Woodhouse for adding multichip support
 *
 *      Aleph One Ltd. and Toby Churchill Ltd. for supporting the
 *      rework for 2K page size chips
 *
 *  TODO:
 *      Enable cached programming for 2k page size chips
 *      Check, if mtd->ecctype should be set to MTD_ECC_HW
 *      if we have HW ecc support.
 *      The AG-AND chips have nice features for speed improvement,
 *      which are not supported yet. Read / program 4 pages in one go.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ecc.h>
#include <linux/mtd/compatmac.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/leds.h>
#include <asm/io.h>

#ifdef CONFIG_MTD_PARTITIONS
#include <linux/mtd/partitions.h>
#endif

/* Define default oob placement schemes for large and small page devices */
static struct nand_oobinfo nand_oob_8 = {
        .useecc = MTD_NANDECC_AUTOPLACE,
        .eccbytes = 3,
        .eccpos = {0, 1, 2},
        .oobfree = {{3, 2}, {6, 2}}
};

static struct nand_oobinfo nand_oob_16 = {
        .useecc = MTD_NANDECC_AUTOPLACE,
        .eccbytes = 6,
        .eccpos = {0, 1, 2, 3, 6, 7},
        .oobfree = {{8, 8}}
};

static struct nand_oobinfo nand_oob_64 = {
        .useecc = MTD_NANDECC_AUTOPLACE,
        .eccbytes = 24,
        .eccpos = {
                   40, 41, 42, 43, 44, 45, 46, 47,
                   48, 49, 50, 51, 52, 53, 54, 55,
                   56, 57, 58, 59, 60, 61, 62, 63},
        .oobfree = {{2, 38}}
};

/* This is used for padding purposes in nand_write_oob */
static uint8_t ffchars[] = {
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};

/*
 * NAND low-level MTD interface functions
 */
static void nand_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len);
static void nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len);
static int nand_verify_buf(struct mtd_info *mtd, const uint8_t *buf, int len);

static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
                     size_t *retlen, uint8_t *buf);
static int nand_read_oob(struct mtd_info *mtd, loff_t from, size_t len,
                         size_t *retlen, uint8_t *buf);
static int nand_write(struct mtd_info *mtd, loff_t to, size_t len,
                      size_t *retlen, const uint8_t *buf);
static int nand_write_oob(struct mtd_info *mtd, loff_t to, size_t len,
                          size_t *retlen, const uint8_t *buf);
static int nand_erase(struct mtd_info *mtd, struct erase_info *instr);
static void nand_sync(struct mtd_info *mtd);

/* Some internal functions */
static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
                           int page, uint8_t * oob_buf,
                           struct nand_oobinfo *oobsel, int mode);
#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
static int nand_verify_pages(struct mtd_info *mtd, struct nand_chip *chip,
                             int page, int numpages, uint8_t *oob_buf,
                             struct nand_oobinfo *oobsel, int chipnr,
                             int oobmode);
#else
#define nand_verify_pages(...) (0)
#endif

static int nand_get_device(struct nand_chip *chip, struct mtd_info *mtd,
                           int new_state);

/*
 * For devices which display every fart in the system on a seperate LED. Is
 * compiled away when LED support is disabled.
 */
DEFINE_LED_TRIGGER(nand_led_trigger);

/**
 * nand_release_device - [GENERIC] release chip
 * @mtd:        MTD device structure
 *
 * Deselect, release chip lock and wake up anyone waiting on the device
 */
static void nand_release_device(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;

        /* De-select the NAND device */
        chip->select_chip(mtd, -1);

        /* Release the controller and the chip */
        spin_lock(&chip->controller->lock);
        chip->controller->active = NULL;
        chip->state = FL_READY;
        wake_up(&chip->controller->wq);
        spin_unlock(&chip->controller->lock);
}

/**
 * nand_read_byte - [DEFAULT] read one byte from the chip
 * @mtd:        MTD device structure
 *
 * Default read function for 8bit buswith
 */
static uint8_t nand_read_byte(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;
        return readb(chip->IO_ADDR_R);
}

/**
 * nand_read_byte16 - [DEFAULT] read one byte endianess aware from the chip
 * @mtd:        MTD device structure
 *
 * Default read function for 16bit buswith with
 * endianess conversion
 */
static uint8_t nand_read_byte16(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;
        return (uint8_t) cpu_to_le16(readw(chip->IO_ADDR_R));
}

/**
 * nand_read_word - [DEFAULT] read one word from the chip
 * @mtd:        MTD device structure
 *
 * Default read function for 16bit buswith without
 * endianess conversion
 */
static u16 nand_read_word(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;
        return readw(chip->IO_ADDR_R);
}

/**
 * nand_select_chip - [DEFAULT] control CE line
 * @mtd:        MTD device structure
 * @chip:       chipnumber to select, -1 for deselect
 *
 * Default select function for 1 chip devices.
 */
static void nand_select_chip(struct mtd_info *mtd, int chipnr)
{
        struct nand_chip *chip = mtd->priv;

        switch (chipnr) {
        case -1:
                chip->cmd_ctrl(mtd, NAND_CMD_NONE, 0 | NAND_CTRL_CHANGE);
                break;
        case 0:
                chip->cmd_ctrl(mtd, NAND_CMD_NONE,
                               NAND_NCE | NAND_CTRL_CHANGE);
                break;

        default:
                BUG();
        }
}

/**
 * nand_write_buf - [DEFAULT] write buffer to chip
 * @mtd:        MTD device structure
 * @buf:        data buffer
 * @len:        number of bytes to write
 *
 * Default write function for 8bit buswith
 */
static void nand_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
{
        int i;
        struct nand_chip *chip = mtd->priv;

        for (i = 0; i < len; i++)
                writeb(buf[i], chip->IO_ADDR_W);
}

/**
 * nand_read_buf - [DEFAULT] read chip data into buffer
 * @mtd:        MTD device structure
 * @buf:        buffer to store date
 * @len:        number of bytes to read
 *
 * Default read function for 8bit buswith
 */
static void nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
        int i;
        struct nand_chip *chip = mtd->priv;

        for (i = 0; i < len; i++)
                buf[i] = readb(chip->IO_ADDR_R);
}

/**
 * nand_verify_buf - [DEFAULT] Verify chip data against buffer
 * @mtd:        MTD device structure
 * @buf:        buffer containing the data to compare
 * @len:        number of bytes to compare
 *
 * Default verify function for 8bit buswith
 */
static int nand_verify_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
{
        int i;
        struct nand_chip *chip = mtd->priv;

        for (i = 0; i < len; i++)
                if (buf[i] != readb(chip->IO_ADDR_R))
                        return -EFAULT;

        return 0;
}

/**
 * nand_write_buf16 - [DEFAULT] write buffer to chip
 * @mtd:        MTD device structure
 * @buf:        data buffer
 * @len:        number of bytes to write
 *
 * Default write function for 16bit buswith
 */
static void nand_write_buf16(struct mtd_info *mtd, const uint8_t *buf, int len)
{
        int i;
        struct nand_chip *chip = mtd->priv;
        u16 *p = (u16 *) buf;
        len >>= 1;

        for (i = 0; i < len; i++)
                writew(p[i], chip->IO_ADDR_W);

}

/**
 * nand_read_buf16 - [DEFAULT] read chip data into buffer
 * @mtd:        MTD device structure
 * @buf:        buffer to store date
 * @len:        number of bytes to read
 *
 * Default read function for 16bit buswith
 */
static void nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len)
{
        int i;
        struct nand_chip *chip = mtd->priv;
        u16 *p = (u16 *) buf;
        len >>= 1;

        for (i = 0; i < len; i++)
                p[i] = readw(chip->IO_ADDR_R);
}

/**
 * nand_verify_buf16 - [DEFAULT] Verify chip data against buffer
 * @mtd:        MTD device structure
 * @buf:        buffer containing the data to compare
 * @len:        number of bytes to compare
 *
 * Default verify function for 16bit buswith
 */
static int nand_verify_buf16(struct mtd_info *mtd, const uint8_t *buf, int len)
{
        int i;
        struct nand_chip *chip = mtd->priv;
        u16 *p = (u16 *) buf;
        len >>= 1;

        for (i = 0; i < len; i++)
                if (p[i] != readw(chip->IO_ADDR_R))
                        return -EFAULT;

        return 0;
}

/**
 * nand_block_bad - [DEFAULT] Read bad block marker from the chip
 * @mtd:        MTD device structure
 * @ofs:        offset from device start
 * @getchip:    0, if the chip is already selected
 *
 * Check, if the block is bad.
 */
static int nand_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
{
        int page, chipnr, res = 0;
        struct nand_chip *chip = mtd->priv;
        u16 bad;

        if (getchip) {
                page = (int)(ofs >> chip->page_shift);
                chipnr = (int)(ofs >> chip->chip_shift);

                nand_get_device(chip, mtd, FL_READING);

                /* Select the NAND device */
                chip->select_chip(mtd, chipnr);
        } else
                page = (int)ofs;

        if (chip->options & NAND_BUSWIDTH_16) {
                chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos & 0xFE,
                              page & chip->pagemask);
                bad = cpu_to_le16(chip->read_word(mtd));
                if (chip->badblockpos & 0x1)
                        bad >>= 8;
                if ((bad & 0xFF) != 0xff)
                        res = 1;
        } else {
                chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos,
                              page & chip->pagemask);
                if (chip->read_byte(mtd) != 0xff)
                        res = 1;
        }

        if (getchip)
                nand_release_device(mtd);

        return res;
}

/**
 * nand_default_block_markbad - [DEFAULT] mark a block bad
 * @mtd:        MTD device structure
 * @ofs:        offset from device start
 *
 * This is the default implementation, which can be overridden by
 * a hardware specific driver.
*/
static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        struct nand_chip *chip = mtd->priv;
        uint8_t buf[2] = { 0, 0 };
        size_t retlen;
        int block;

        /* Get block number */
        block = ((int)ofs) >> chip->bbt_erase_shift;
        if (chip->bbt)
                chip->bbt[block >> 2] |= 0x01 << ((block & 0x03) << 1);

        /* Do we have a flash based bad block table ? */
        if (chip->options & NAND_USE_FLASH_BBT)
                return nand_update_bbt(mtd, ofs);

        /* We write two bytes, so we dont have to mess with 16 bit access */
        ofs += mtd->oobsize + (chip->badblockpos & ~0x01);
        return nand_write_oob(mtd, ofs, 2, &retlen, buf);
}

/**
 * nand_check_wp - [GENERIC] check if the chip is write protected
 * @mtd:        MTD device structure
 * Check, if the device is write protected
 *
 * The function expects, that the device is already selected
 */
static int nand_check_wp(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;
        /* Check the WP bit */
        chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
        return (chip->read_byte(mtd) & NAND_STATUS_WP) ? 0 : 1;
}

/**
 * nand_block_checkbad - [GENERIC] Check if a block is marked bad
 * @mtd:        MTD device structure
 * @ofs:        offset from device start
 * @getchip:    0, if the chip is already selected
 * @allowbbt:   1, if its allowed to access the bbt area
 *
 * Check, if the block is bad. Either by reading the bad block table or
 * calling of the scan function.
 */
static int nand_block_checkbad(struct mtd_info *mtd, loff_t ofs, int getchip,
                               int allowbbt)
{
        struct nand_chip *chip = mtd->priv;

        if (!chip->bbt)
                return chip->block_bad(mtd, ofs, getchip);

        /* Return info from the table */
        return nand_isbad_bbt(mtd, ofs, allowbbt);
}

/*
 * Wait for the ready pin, after a command
 * The timeout is catched later.
 */
static void nand_wait_ready(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;
        unsigned long timeo = jiffies + 2;

        led_trigger_event(nand_led_trigger, LED_FULL);
        /* wait until command is processed or timeout occures */
        do {
                if (chip->dev_ready(mtd))
                        break;
                touch_softlockup_watchdog();
        } while (time_before(jiffies, timeo));
        led_trigger_event(nand_led_trigger, LED_OFF);
}

/**
 * nand_command - [DEFAULT] Send command to NAND device
 * @mtd:        MTD device structure
 * @command:    the command to be sent
 * @column:     the column address for this command, -1 if none
 * @page_addr:  the page address for this command, -1 if none
 *
 * Send command to NAND device. This function is used for small page
 * devices (256/512 Bytes per page)
 */
static void nand_command(struct mtd_info *mtd, unsigned int command,
                         int column, int page_addr)
{
        register struct nand_chip *chip = mtd->priv;
        int ctrl = NAND_CTRL_CLE | NAND_CTRL_CHANGE;

        /*
         * Write out the command to the device.
         */
        if (command == NAND_CMD_SEQIN) {
                int readcmd;

                if (column >= mtd->writesize) {
                        /* OOB area */
                        column -= mtd->writesize;
                        readcmd = NAND_CMD_READOOB;
                } else if (column < 256) {
                        /* First 256 bytes --> READ0 */
                        readcmd = NAND_CMD_READ0;
                } else {
                        column -= 256;
                        readcmd = NAND_CMD_READ1;
                }
                chip->cmd_ctrl(mtd, readcmd, ctrl);
                ctrl &= ~NAND_CTRL_CHANGE;
        }
        chip->cmd_ctrl(mtd, command, ctrl);

        /*
         * Address cycle, when necessary
         */
        ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
        /* Serially input address */
        if (column != -1) {
                /* Adjust columns for 16 bit buswidth */
                if (chip->options & NAND_BUSWIDTH_16)
                        column >>= 1;
                chip->cmd_ctrl(mtd, column, ctrl);
                ctrl &= ~NAND_CTRL_CHANGE;
        }
        if (page_addr != -1) {
                chip->cmd_ctrl(mtd, page_addr, ctrl);
                ctrl &= ~NAND_CTRL_CHANGE;
                chip->cmd_ctrl(mtd, page_addr >> 8, ctrl);
                /* One more address cycle for devices > 32MiB */
                if (chip->chipsize > (32 << 20))
                        chip->cmd_ctrl(mtd, page_addr >> 16, ctrl);
        }
        chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);

        /*
         * program and erase have their own busy handlers
         * status and sequential in needs no delay
         */
        switch (command) {

        case NAND_CMD_PAGEPROG:
        case NAND_CMD_ERASE1:
        case NAND_CMD_ERASE2:
        case NAND_CMD_SEQIN:
        case NAND_CMD_STATUS:
                chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE);
                return;

        case NAND_CMD_RESET:
                if (chip->dev_ready)
                        break;
                udelay(chip->chip_delay);
                chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
                               NAND_CTRL_CLE | NAND_CTRL_CHANGE);
                chip->cmd_ctrl(mtd,
                               NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
                while (!(chip->read_byte(mtd) & NAND_STATUS_READY)) ;
                return;

                /* This applies to read commands */
        default:
                /*
                 * If we don't have access to the busy pin, we apply the given
                 * command delay
                 */
                if (!chip->dev_ready) {
                        udelay(chip->chip_delay);
                        return;
                }
        }
        /* Apply this short delay always to ensure that we do wait tWB in
         * any case on any machine. */
        ndelay(100);

        nand_wait_ready(mtd);
}

/**
 * nand_command_lp - [DEFAULT] Send command to NAND large page device
 * @mtd:        MTD device structure
 * @command:    the command to be sent
 * @column:     the column address for this command, -1 if none
 * @page_addr:  the page address for this command, -1 if none
 *
 * Send command to NAND device. This is the version for the new large page
 * devices We dont have the separate regions as we have in the small page
 * devices.  We must emulate NAND_CMD_READOOB to keep the code compatible.
 *
 */
static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
                            int column, int page_addr)
{
        register struct nand_chip *chip = mtd->priv;

        /* Emulate NAND_CMD_READOOB */
        if (command == NAND_CMD_READOOB) {
                column += mtd->writesize;
                command = NAND_CMD_READ0;
        }

        /* Command latch cycle */
        chip->cmd_ctrl(mtd, command & 0xff,
                       NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);

        if (column != -1 || page_addr != -1) {
                int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;

                /* Serially input address */
                if (column != -1) {
                        /* Adjust columns for 16 bit buswidth */
                        if (chip->options & NAND_BUSWIDTH_16)
                                column >>= 1;
                        chip->cmd_ctrl(mtd, column, ctrl);
                        ctrl &= ~NAND_CTRL_CHANGE;
                        chip->cmd_ctrl(mtd, column >> 8, ctrl);
                }
                if (page_addr != -1) {
                        chip->cmd_ctrl(mtd, page_addr, ctrl);
                        chip->cmd_ctrl(mtd, page_addr >> 8,
                                       NAND_NCE | NAND_ALE);
                        /* One more address cycle for devices > 128MiB */
                        if (chip->chipsize > (128 << 20))
                                chip->cmd_ctrl(mtd, page_addr >> 16,
                                               NAND_NCE | NAND_ALE);
                }
        }
        chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);

        /*
         * program and erase have their own busy handlers
         * status, sequential in, and deplete1 need no delay
         */
        switch (command) {

        case NAND_CMD_CACHEDPROG:
        case NAND_CMD_PAGEPROG:
        case NAND_CMD_ERASE1:
        case NAND_CMD_ERASE2:
        case NAND_CMD_SEQIN:
        case NAND_CMD_STATUS:
        case NAND_CMD_DEPLETE1:
                return;

                /*
                 * read error status commands require only a short delay
                 */
        case NAND_CMD_STATUS_ERROR:
        case NAND_CMD_STATUS_ERROR0:
        case NAND_CMD_STATUS_ERROR1:
        case NAND_CMD_STATUS_ERROR2:
        case NAND_CMD_STATUS_ERROR3:
                udelay(chip->chip_delay);
                return;

        case NAND_CMD_RESET:
                if (chip->dev_ready)
                        break;
                udelay(chip->chip_delay);
                chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
                               NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
                chip->cmd_ctrl(mtd, NAND_CMD_NONE,
                               NAND_NCE | NAND_CTRL_CHANGE);
                while (!(chip->read_byte(mtd) & NAND_STATUS_READY)) ;
                return;

        case NAND_CMD_READ0:
                chip->cmd_ctrl(mtd, NAND_CMD_READSTART,
                               NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
                chip->cmd_ctrl(mtd, NAND_CMD_NONE,
                               NAND_NCE | NAND_CTRL_CHANGE);

                /* This applies to read commands */
        default:
                /*
                 * If we don't have access to the busy pin, we apply the given
                 * command delay
                 */
                if (!chip->dev_ready) {
                        udelay(chip->chip_delay);
                        return;
                }
        }

        /* Apply this short delay always to ensure that we do wait tWB in
         * any case on any machine. */
        ndelay(100);

        nand_wait_ready(mtd);
}

/**
 * nand_get_device - [GENERIC] Get chip for selected access
 * @this:       the nand chip descriptor
 * @mtd:        MTD device structure
 * @new_state:  the state which is requested
 *
 * Get the device and lock it for exclusive access
 */
static int
nand_get_device(struct nand_chip *chip, struct mtd_info *mtd, int new_state)
{
        spinlock_t *lock = &chip->controller->lock;
        wait_queue_head_t *wq = &chip->controller->wq;
        DECLARE_WAITQUEUE(wait, current);
 retry:
        spin_lock(lock);

        /* Hardware controller shared among independend devices */
        /* Hardware controller shared among independend devices */
        if (!chip->controller->active)
                chip->controller->active = chip;

        if (chip->controller->active == chip && chip->state == FL_READY) {
                chip->state = new_state;
                spin_unlock(lock);
                return 0;
        }
        if (new_state == FL_PM_SUSPENDED) {
                spin_unlock(lock);
                return (chip->state == FL_PM_SUSPENDED) ? 0 : -EAGAIN;
        }
        set_current_state(TASK_UNINTERRUPTIBLE);
        add_wait_queue(wq, &wait);
        spin_unlock(lock);
        schedule();
        remove_wait_queue(wq, &wait);
        goto retry;
}

/**
 * nand_wait - [DEFAULT]  wait until the command is done
 * @mtd:        MTD device structure
 * @this:       NAND chip structure
 * @state:      state to select the max. timeout value
 *
 * Wait for command done. This applies to erase and program only
 * Erase can take up to 400ms and program up to 20ms according to
 * general NAND and SmartMedia specs
 *
*/
static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip, int state)
{

        unsigned long timeo = jiffies;
        int status;

        if (state == FL_ERASING)
                timeo += (HZ * 400) / 1000;
        else
                timeo += (HZ * 20) / 1000;

        led_trigger_event(nand_led_trigger, LED_FULL);

        /* Apply this short delay always to ensure that we do wait tWB in
         * any case on any machine. */
        ndelay(100);

        if ((state == FL_ERASING) && (chip->options & NAND_IS_AND))
                chip->cmdfunc(mtd, NAND_CMD_STATUS_MULTI, -1, -1);
        else
                chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);

        while (time_before(jiffies, timeo)) {
                /* Check, if we were interrupted */
                if (chip->state != state)
                        return 0;

                if (chip->dev_ready) {
                        if (chip->dev_ready(mtd))
                                break;
                } else {
                        if (chip->read_byte(mtd) & NAND_STATUS_READY)
                                break;
                }
                cond_resched();
        }
        led_trigger_event(nand_led_trigger, LED_OFF);

        status = (int)chip->read_byte(mtd);
        return status;
}

/**
 * nand_write_page - [GENERIC] write one page
 * @mtd:        MTD device structure
 * @this:       NAND chip structure
 * @page:       startpage inside the chip, must be called with (page & chip->pagemask)
 * @oob_buf:    out of band data buffer
 * @oobsel:     out of band selecttion structre
 * @cached:     1 = enable cached programming if supported by chip
 *
 * Nand_page_program function is used for write and writev !
 * This function will always program a full page of data
 * If you call it with a non page aligned buffer, you're lost :)
 *
 * Cached programming is not supported yet.
 */
static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip, int page,
                           uint8_t *oob_buf, struct nand_oobinfo *oobsel, int cached)
{
        int i, status;
        uint8_t ecc_code[32];
        int eccmode = oobsel->useecc ? chip->ecc.mode : NAND_ECC_NONE;
        int *oob_config = oobsel->eccpos;
        int datidx = 0, eccidx = 0, eccsteps = chip->ecc.steps;
        int eccbytes = 0;

        /* FIXME: Enable cached programming */
        cached = 0;

        /* Send command to begin auto page programming */
        chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);

        /* Write out complete page of data, take care of eccmode */
        switch (eccmode) {
                /* No ecc, write all */
        case NAND_ECC_NONE:
                printk(KERN_WARNING "Writing data without ECC to NAND-FLASH is not recommended\n");
                chip->write_buf(mtd, chip->data_poi, mtd->writesize);
                break;

                /* Software ecc 3/256, write all */
        case NAND_ECC_SOFT:
                for (; eccsteps; eccsteps--) {
                        chip->ecc.calculate(mtd, &chip->data_poi[datidx], ecc_code);
                        for (i = 0; i < 3; i++, eccidx++)
                                oob_buf[oob_config[eccidx]] = ecc_code[i];
                        datidx += chip->ecc.size;
                }
                chip->write_buf(mtd, chip->data_poi, mtd->writesize);
                break;
        default:
                eccbytes = chip->ecc.bytes;
                for (; eccsteps; eccsteps--) {
                        /* enable hardware ecc logic for write */
                        chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
                        chip->write_buf(mtd, &chip->data_poi[datidx], chip->ecc.size);
                        chip->ecc.calculate(mtd, &chip->data_poi[datidx], ecc_code);
                        for (i = 0; i < eccbytes; i++, eccidx++)
                                oob_buf[oob_config[eccidx]] = ecc_code[i];
                        /* If the hardware ecc provides syndromes then
                         * the ecc code must be written immidiately after
                         * the data bytes (words) */
                        if (chip->options & NAND_HWECC_SYNDROME)
                                chip->write_buf(mtd, ecc_code, eccbytes);
                        datidx += chip->ecc.size;
                }
                break;
        }

        /* Write out OOB data */
        if (chip->options & NAND_HWECC_SYNDROME)
                chip->write_buf(mtd, &oob_buf[oobsel->eccbytes], mtd->oobsize - oobsel->eccbytes);
        else
                chip->write_buf(mtd, oob_buf, mtd->oobsize);

        /* Send command to actually program the data */
        chip->cmdfunc(mtd, cached ? NAND_CMD_CACHEDPROG : NAND_CMD_PAGEPROG, -1, -1);

        if (!cached) {
                /* call wait ready function */
                status = chip->waitfunc(mtd, chip, FL_WRITING);

                /* See if operation failed and additional status checks are available */
                if ((status & NAND_STATUS_FAIL) && (chip->errstat)) {
                        status = chip->errstat(mtd, chip, FL_WRITING, status, page);
                }

                /* See if device thinks it succeeded */
                if (status & NAND_STATUS_FAIL) {
                        DEBUG(MTD_DEBUG_LEVEL0, "%s: " "Failed write, page 0x%08x, ", __FUNCTION__, page);
                        return -EIO;
                }
        } else {
                /* FIXME: Implement cached programming ! */
                /* wait until cache is ready */
                // status = chip->waitfunc (mtd, this, FL_CACHEDRPG);
        }
        return 0;
}

#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
/**
 * nand_verify_pages - [GENERIC] verify the chip contents after a write
 * @mtd:        MTD device structure
 * @this:       NAND chip structure
 * @page:       startpage inside the chip, must be called with (page & chip->pagemask)
 * @numpages:   number of pages to verify
 * @oob_buf:    out of band data buffer
 * @oobsel:     out of band selecttion structre
 * @chipnr:     number of the current chip
 * @oobmode:    1 = full buffer verify, 0 = ecc only
 *
 * The NAND device assumes that it is always writing to a cleanly erased page.
 * Hence, it performs its internal write verification only on bits that
 * transitioned from 1 to 0. The device does NOT verify the whole page on a
 * byte by byte basis. It is possible that the page was not completely erased
 * or the page is becoming unusable due to wear. The read with ECC would catch
 * the error later when the ECC page check fails, but we would rather catch
 * it early in the page write stage. Better to write no data than invalid data.
 */
static int nand_verify_pages(struct mtd_info *mtd, struct nand_chip *chip, int page, int numpages,
                             uint8_t *oob_buf, struct nand_oobinfo *oobsel, int chipnr, int oobmode)
{
        int i, j, datidx = 0, oobofs = 0, res = -EIO;
        int eccsteps = chip->eccsteps;
        int hweccbytes;
        uint8_t oobdata[64];

        hweccbytes = (chip->options & NAND_HWECC_SYNDROME) ? (oobsel->eccbytes / eccsteps) : 0;

        /* Send command to read back the first page */
        chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);

        for (;;) {
                for (j = 0; j < eccsteps; j++) {
                        /* Loop through and verify the data */
                        if (chip->verify_buf(mtd, &chip->data_poi[datidx], mtd->eccsize)) {
                                DEBUG(MTD_DEBUG_LEVEL0, "%s: " "Failed write verify, page 0x%08x ", __FUNCTION__, page);
                                goto out;
                        }
                        datidx += mtd->eccsize;
                        /* Have we a hw generator layout ? */
                        if (!hweccbytes)
                                continue;
                        if (chip->verify_buf(mtd, &chip->oob_buf[oobofs], hweccbytes)) {
                                DEBUG(MTD_DEBUG_LEVEL0, "%s: " "Failed write verify, page 0x%08x ", __FUNCTION__, page);
                                goto out;
                        }
                        oobofs += hweccbytes;
                }

                /* check, if we must compare all data or if we just have to
                 * compare the ecc bytes
                 */
                if (oobmode) {
                        if (chip->verify_buf(mtd, &oob_buf[oobofs], mtd->oobsize - hweccbytes * eccsteps)) {
                                DEBUG(MTD_DEBUG_LEVEL0, "%s: " "Failed write verify, page 0x%08x ", __FUNCTION__, page);
                                goto out;
                        }
                } else {
                        /* Read always, else autoincrement fails */
                        chip->read_buf(mtd, oobdata, mtd->oobsize - hweccbytes * eccsteps);

                        if (oobsel->useecc != MTD_NANDECC_OFF && !hweccbytes) {
                                int ecccnt = oobsel->eccbytes;

                                for (i = 0; i < ecccnt; i++) {
                                        int idx = oobsel->eccpos[i];
                                        if (oobdata[idx] != oob_buf[oobofs + idx]) {
                                                DEBUG(MTD_DEBUG_LEVEL0, "%s: Failed ECC write verify, page 0x%08x, %6i bytes were succesful\n",
                                                      __FUNCTION__, page, i);
                                                goto out;
                                        }
                                }
                        }
                }
                oobofs += mtd->oobsize - hweccbytes * eccsteps;
                page++;
                numpages--;

                /* Apply delay or wait for ready/busy pin
                 * Do this before the AUTOINCR check, so no problems
                 * arise if a chip which does auto increment
                 * is marked as NOAUTOINCR by the board driver.
                 * Do this also before returning, so the chip is
                 * ready for the next command.
                 */
                if (!chip->dev_ready)
                        udelay(chip->chip_delay);
                else
                        nand_wait_ready(mtd);

                /* All done, return happy */
                if (!numpages)
                        return 0;

                /* Check, if the chip supports auto page increment */
                if (!NAND_CANAUTOINCR(this))
                        chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
        }
        /*
         * Terminate the read command. We come here in case of an error
         * So we must issue a reset command.
         */
 out:
        chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
        return res;
}
#endif

/**
 * nand_read_page_swecc - {REPLACABLE] software ecc based page read function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        buffer to store read data
 */
static int nand_read_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
                                uint8_t *buf)
{
        int i, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
        int eccsteps = chip->ecc.steps;
        uint8_t *p = buf;
        uint8_t *ecc_calc = chip->oob_buf + mtd->oobsize;
        uint8_t *ecc_code = ecc_calc + mtd->oobsize;
        int *eccpos = chip->autooob->eccpos;

        chip->read_buf(mtd, buf, mtd->writesize);
        chip->read_buf(mtd, chip->oob_buf, mtd->oobsize);

        if (chip->ecc.mode == NAND_ECC_NONE)
                return 0;

        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
                chip->ecc.calculate(mtd, p, &ecc_calc[i]);

        for (i = 0; i < chip->ecc.total; i++)
                ecc_code[i] = chip->oob_buf[eccpos[i]];

        eccsteps = chip->ecc.steps;
        p = buf;

        for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                int stat;

                stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
                if (stat == -1)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;
        }
        return 0;
}

/**
 * nand_read_page_hwecc - {REPLACABLE] hardware ecc based page read function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        buffer to store read data
 *
 * Not for syndrome calculating ecc controllers which need a special oob layout
 */
static int nand_read_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
                                uint8_t *buf)
{
        int i, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
        int eccsteps = chip->ecc.steps;
        uint8_t *p = buf;
        uint8_t *ecc_calc = chip->oob_buf + mtd->oobsize;
        uint8_t *ecc_code = ecc_calc + mtd->oobsize;
        int *eccpos = chip->autooob->eccpos;

        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                chip->ecc.hwctl(mtd, NAND_ECC_READ);
                chip->read_buf(mtd, p, eccsize);
                chip->ecc.calculate(mtd, p, &ecc_calc[i]);
        }
        chip->read_buf(mtd, chip->oob_buf, mtd->oobsize);

        for (i = 0; i < chip->ecc.total; i++)
                ecc_code[i] = chip->oob_buf[eccpos[i]];

        eccsteps = chip->ecc.steps;
        p = buf;

        for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                int stat;

                stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
                if (stat == -1)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;
        }
        return 0;
}

/**
 * nand_read_page_syndrome - {REPLACABLE] hardware ecc syndrom based page read
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        buffer to store read data
 *
 * The hw generator calculates the error syndrome automatically. Therefor
 * we need a special oob layout and .
 */
static int nand_read_page_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
                                   uint8_t *buf)
{
        int i, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
        int eccsteps = chip->ecc.steps;
        uint8_t *p = buf;
        uint8_t *oob = chip->oob_buf;

        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                int stat;

                chip->ecc.hwctl(mtd, NAND_ECC_READ);
                chip->read_buf(mtd, p, eccsize);

                if (chip->ecc.prepad) {
                        chip->read_buf(mtd, oob, chip->ecc.prepad);
                        oob += chip->ecc.prepad;
                }

                chip->ecc.hwctl(mtd, NAND_ECC_READSYN);
                chip->read_buf(mtd, oob, eccbytes);
                stat = chip->ecc.correct(mtd, p, oob, NULL);

                if (stat == -1)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;

                oob += eccbytes;

                if (chip->ecc.postpad) {
                        chip->read_buf(mtd, oob, chip->ecc.postpad);
                        oob += chip->ecc.postpad;
                }
        }

        /* Calculate remaining oob bytes */
        i = oob - chip->oob_buf;
        if (i)
                chip->read_buf(mtd, oob, i);

        return 0;
}

/**
 * nand_do_read - [Internal] Read data with ECC
 *
 * @mtd:        MTD device structure
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @retlen:     pointer to variable to store the number of read bytes
 * @buf:        the databuffer to put data
 *
 * Internal function. Called with chip held.
 */
int nand_do_read(struct mtd_info *mtd, loff_t from, size_t len,
                 size_t *retlen, uint8_t *buf)
{
        int chipnr, page, realpage, col, bytes, aligned;
        struct nand_chip *chip = mtd->priv;
        struct mtd_ecc_stats stats;
        int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
        int sndcmd = 1;
        int ret = 0;
        uint32_t readlen = len;
        uint8_t *bufpoi;

        stats = mtd->ecc_stats;

        chipnr = (int)(from >> chip->chip_shift);
        chip->select_chip(mtd, chipnr);

        realpage = (int)(from >> chip->page_shift);
        page = realpage & chip->pagemask;

        col = (int)(from & (mtd->writesize - 1));

        while(1) {
                bytes = min(mtd->writesize - col, readlen);
                aligned = (bytes == mtd->writesize);

                /* Is the current page in the buffer ? */
                if (realpage != chip->pagebuf) {
                        bufpoi = aligned ? buf : chip->data_buf;

                        if (likely(sndcmd)) {
                                chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
                                sndcmd = 0;
                        }

                        /* Now read the page into the buffer */
                        ret = chip->ecc.read_page(mtd, chip, bufpoi);
                        if (ret < 0)
                                break;

                        /* Transfer not aligned data */
                        if (!aligned) {
                                chip->pagebuf = realpage;
                                memcpy(buf, chip->data_buf + col, bytes);
                        }

                        if (!(chip->options & NAND_NO_READRDY)) {
                                /*
                                 * Apply delay or wait for ready/busy pin. Do
                                 * this before the AUTOINCR check, so no
                                 * problems arise if a chip which does auto
                                 * increment is marked as NOAUTOINCR by the
                                 * board driver.
                                 */
                                if (!chip->dev_ready)
                                        udelay(chip->chip_delay);
                                else
                                        nand_wait_ready(mtd);
                        }
                } else
                        memcpy(buf, chip->data_buf + col, bytes);

                buf += bytes;
                readlen -= bytes;

                if (!readlen)
                        break;

                /* For subsequent reads align to page boundary. */
                col = 0;
                /* Increment page address */
                realpage++;

                page = realpage & chip->pagemask;
                /* Check, if we cross a chip boundary */
                if (!page) {
                        chipnr++;
                        chip->select_chip(mtd, -1);
                        chip->select_chip(mtd, chipnr);
                }

                /* Check, if the chip supports auto page increment
                 * or if we have hit a block boundary.
                 */
                if (!NAND_CANAUTOINCR(chip) || !(page & blkcheck))
                        sndcmd = 1;
        }

        *retlen = len - (size_t) readlen;

        if (ret)
                return ret;

        return mtd->ecc_stats.failed - stats.failed ? -EBADMSG : 0;
}

/**
 * nand_read - [MTD Interface] MTD compability function for nand_do_read_ecc
 * @mtd:        MTD device structure
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @retlen:     pointer to variable to store the number of read bytes
 * @buf:        the databuffer to put data
 *
 * Get hold of the chip and call nand_do_read
 */
static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
                     size_t *retlen, uint8_t *buf)
{
        int ret;

        *retlen = 0;
        /* Do not allow reads past end of device */
        if ((from + len) > mtd->size)
                return -EINVAL;
        if (!len)
                return 0;

        nand_get_device(mtd->priv, mtd, FL_READING);

        ret = nand_do_read(mtd, from, len, retlen, buf);

        nand_release_device(mtd);

        return ret;
}

/**
 * nand_read_oob - [MTD Interface] NAND read out-of-band
 * @mtd:        MTD device structure
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @retlen:     pointer to variable to store the number of read bytes
 * @buf:        the databuffer to put data
 *
 * NAND read out-of-band data from the spare area
 */
static int nand_read_oob(struct mtd_info *mtd, loff_t from, size_t len,
                         size_t *retlen, uint8_t *buf)
{
        int col, page, realpage, chipnr, sndcmd = 1;
        struct nand_chip *chip = mtd->priv;
        int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
        int readlen = len;

        DEBUG(MTD_DEBUG_LEVEL3, "nand_read_oob: from = 0x%08x, len = %i\n",
              (unsigned int)from, (int)len);

        /* Initialize return length value */
        *retlen = 0;

        /* Do not allow reads past end of device */
        if ((from + len) > mtd->size) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_read_oob: "
                      "Attempt read beyond end of device\n");
                return -EINVAL;
        }

        nand_get_device(chip, mtd, FL_READING);

        chipnr = (int)(from >> chip->chip_shift);
        chip->select_chip(mtd, chipnr);

        /* Shift to get page */
        realpage = (int)(from >> chip->page_shift);
        page = realpage & chip->pagemask;

        /* Mask to get column */
        col = from & (mtd->oobsize - 1);

        while(1) {
                int bytes = min((int)(mtd->oobsize - col), readlen);

                if (likely(sndcmd)) {
                        chip->cmdfunc(mtd, NAND_CMD_READOOB, col, page);
                        sndcmd = 0;
                }

                chip->read_buf(mtd, buf, bytes);

                readlen -= bytes;
                if (!readlen)
                        break;

                if (!(chip->options & NAND_NO_READRDY)) {
                        /*
                         * Apply delay or wait for ready/busy pin. Do this
                         * before the AUTOINCR check, so no problems arise if a
                         * chip which does auto increment is marked as
                         * NOAUTOINCR by the board driver.
                         */
                        if (!chip->dev_ready)
                                udelay(chip->chip_delay);
                        else
                                nand_wait_ready(mtd);
                }

                buf += bytes;
                bytes = mtd->oobsize;
                col = 0;

                /* Increment page address */
                realpage++;

                page = realpage & chip->pagemask;
                /* Check, if we cross a chip boundary */
                if (!page) {
                        chipnr++;
                        chip->select_chip(mtd, -1);
                        chip->select_chip(mtd, chipnr);
                }

                /* Check, if the chip supports auto page increment
                 * or if we have hit a block boundary.
                 */
                if (!NAND_CANAUTOINCR(chip) || !(page & blkcheck))
                        sndcmd = 1;
        }

        /* Deselect and wake up anyone waiting on the device */
        nand_release_device(mtd);

        *retlen = len;
        return 0;
}

/**
 * nand_read_raw - [GENERIC] Read raw data including oob into buffer
 * @mtd:        MTD device structure
 * @buf:        temporary buffer
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @ooblen:     number of oob data bytes to read
 *
 * Read raw data including oob into buffer
 */
int nand_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t from, size_t len,
                  size_t ooblen)
{
        struct nand_chip *chip = mtd->priv;
        int page = (int)(from >> chip->page_shift);
        int chipnr = (int)(from >> chip->chip_shift);
        int sndcmd = 1;
        int cnt = 0;
        int pagesize = mtd->writesize + mtd->oobsize;
        int blockcheck;

        /* Do not allow reads past end of device */
        if ((from + len) > mtd->size) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_read_raw: "
                      "Attempt read beyond end of device\n");
                return -EINVAL;
        }

        /* Grab the lock and see if the device is available */
        nand_get_device(chip, mtd, FL_READING);

        chip->select_chip(mtd, chipnr);

        /* Add requested oob length */
        len += ooblen;
        blockcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;

        while (len) {
                if (sndcmd)
                        chip->cmdfunc(mtd, NAND_CMD_READ0, 0,
                                      page & chip->pagemask);
                sndcmd = 0;

                chip->read_buf(mtd, &buf[cnt], pagesize);

                len -= pagesize;
                cnt += pagesize;
                page++;

                if (!chip->dev_ready)
                        udelay(chip->chip_delay);
                else
                        nand_wait_ready(mtd);

                /*
                 * Check, if the chip supports auto page increment or if we
                 * cross a block boundary.
                 */
                if (!NAND_CANAUTOINCR(chip) || !(page & blockcheck))
                        sndcmd = 1;
        }

        /* Deselect and wake up anyone waiting on the device */
        nand_release_device(mtd);
        return 0;
}

/**
 * nand_write_raw - [GENERIC] Write raw data including oob
 * @mtd:        MTD device structure
 * @buf:        source buffer
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @buf:        source buffer
 * @oob:        oob buffer
 *
 * Write raw data including oob
 */
int nand_write_raw(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
                   uint8_t *buf, uint8_t *oob)
{
        struct nand_chip *chip = mtd->priv;
        int page = (int)(to >> chip->page_shift);
        int chipnr = (int)(to >> chip->chip_shift);
        int ret;

        *retlen = 0;

        /* Do not allow writes past end of device */
        if ((to + len) > mtd->size) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_read_raw: Attempt write "
                      "beyond end of device\n");
                return -EINVAL;
        }

        /* Grab the lock and see if the device is available */
        nand_get_device(chip, mtd, FL_WRITING);

        chip->select_chip(mtd, chipnr);
        chip->data_poi = buf;

        while (len != *retlen) {
                ret = nand_write_page(mtd, chip, page, oob, &mtd->oobinfo, 0);
                if (ret)
                        return ret;
                page++;
                *retlen += mtd->writesize;
                chip->data_poi += mtd->writesize;
                oob += mtd->oobsize;
        }

        /* Deselect and wake up anyone waiting on the device */
        nand_release_device(mtd);
        return 0;
}
EXPORT_SYMBOL_GPL(nand_write_raw);

/**
 * nand_prepare_oobbuf - [GENERIC] Prepare the out of band buffer
 * @mtd:        MTD device structure
 * @fsbuf:      buffer given by fs driver
 * @oobsel:     out of band selection structre
 * @autoplace:  1 = place given buffer into the oob bytes
 * @numpages:   number of pages to prepare
 *
 * Return:
 * 1. Filesystem buffer available and autoplacement is off,
 *    return filesystem buffer
 * 2. No filesystem buffer or autoplace is off, return internal
 *    buffer
 * 3. Filesystem buffer is given and autoplace selected
 *    put data from fs buffer into internal buffer and
 *    retrun internal buffer
 *
 * Note: The internal buffer is filled with 0xff. This must
 * be done only once, when no autoplacement happens
 * Autoplacement sets the buffer dirty flag, which
 * forces the 0xff fill before using the buffer again.
 *
*/
static uint8_t *nand_prepare_oobbuf(struct mtd_info *mtd, uint8_t *fsbuf, struct nand_oobinfo *oobsel,
                                   int autoplace, int numpages)
{
        struct nand_chip *chip = mtd->priv;
        int i, len, ofs;

        /* Zero copy fs supplied buffer */
        if (fsbuf && !autoplace)
                return fsbuf;

        /* Check, if the buffer must be filled with ff again */
        if (chip->oobdirty) {
                memset(chip->oob_buf, 0xff, mtd->oobsize << (chip->phys_erase_shift - chip->page_shift));
                chip->oobdirty = 0;
        }

        /* If we have no autoplacement or no fs buffer use the internal one */
        if (!autoplace || !fsbuf)
                return chip->oob_buf;

        /* Walk through the pages and place the data */
        chip->oobdirty = 1;
        ofs = 0;
        while (numpages--) {
                for (i = 0, len = 0; len < mtd->oobavail; i++) {
                        int to = ofs + oobsel->oobfree[i][0];
                        int num = oobsel->oobfree[i][1];
                        memcpy(&chip->oob_buf[to], fsbuf, num);
                        len += num;
                        fsbuf += num;
                }
                ofs += mtd->oobavail;
        }
        return chip->oob_buf;
}

#define NOTALIGNED(x) (x & (mtd->writesize-1)) != 0

/**
 * nand_write - [MTD Interface] NAND write with ECC
 * @mtd:        MTD device structure
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @retlen:     pointer to variable to store the number of written bytes
 * @buf:        the data to write
 *
 * NAND write with ECC
 */
static int nand_write(struct mtd_info *mtd, loff_t to, size_t len,
                          size_t *retlen, const uint8_t *buf)
{
        int startpage, page, ret = -EIO, oob = 0, written = 0, chipnr;
        int autoplace = 0, numpages, totalpages;
        struct nand_chip *chip = mtd->priv;
        uint8_t *oobbuf, *bufstart, *eccbuf = NULL;
        int ppblock = (1 << (chip->phys_erase_shift - chip->page_shift));
        struct nand_oobinfo *oobsel = &mtd->oobinfo;

        DEBUG(MTD_DEBUG_LEVEL3, "nand_write: to = 0x%08x, len = %i\n", (unsigned int)to, (int)len);

        /* Initialize retlen, in case of early exit */
        *retlen = 0;

        /* Do not allow write past end of device */
        if ((to + len) > mtd->size) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_write: Attempt to write past end of page\n");
                return -EINVAL;
        }

        /* reject writes, which are not page aligned */
        if (NOTALIGNED(to) || NOTALIGNED(len)) {
                printk(KERN_NOTICE "nand_write: Attempt to write not page aligned data\n");
                return -EINVAL;
        }

        /* Grab the lock and see if the device is available */
        nand_get_device(chip, mtd, FL_WRITING);

        /* Calculate chipnr */
        chipnr = (int)(to >> chip->chip_shift);
        /* Select the NAND device */
        chip->select_chip(mtd, chipnr);

        /* Check, if it is write protected */
        if (nand_check_wp(mtd))
                goto out;

        /* Autoplace of oob data ? Use the default placement scheme */
        if (oobsel->useecc == MTD_NANDECC_AUTOPLACE) {
                oobsel = chip->autooob;
                autoplace = 1;
        }
        if (oobsel->useecc == MTD_NANDECC_AUTOPL_USR)
                autoplace = 1;

        /* Setup variables and oob buffer */
        totalpages = len >> chip->page_shift;
        page = (int)(to >> chip->page_shift);
        /* Invalidate the page cache, if we write to the cached page */
        if (page <= chip->pagebuf && chip->pagebuf < (page + totalpages))
                chip->pagebuf = -1;

        /* Set it relative to chip */
        page &= chip->pagemask;
        startpage = page;
        /* Calc number of pages we can write in one go */
        numpages = min(ppblock - (startpage & (ppblock - 1)), totalpages);
        oobbuf = nand_prepare_oobbuf(mtd, eccbuf, oobsel, autoplace, numpages);
        bufstart = (uint8_t *) buf;

        /* Loop until all data is written */
        while (written < len) {

                chip->data_poi = (uint8_t *) &buf[written];
                /* Write one page. If this is the last page to write
                 * or the last page in this block, then use the
                 * real pageprogram command, else select cached programming
                 * if supported by the chip.
                 */
                ret = nand_write_page(mtd, chip, page, &oobbuf[oob], oobsel, (--numpages > 0));
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "nand_write: write_page failed %d\n", ret);
                        goto out;
                }
                /* Next oob page */
                oob += mtd->oobsize;
                /* Update written bytes count */
                written += mtd->writesize;
                if (written == len)
                        goto cmp;

                /* Increment page address */
                page++;

                /* Have we hit a block boundary ? Then we have to verify and
                 * if verify is ok, we have to setup the oob buffer for
                 * the next pages.
                 */
                if (!(page & (ppblock - 1))) {
                        int ofs;
                        chip->data_poi = bufstart;
                        ret = nand_verify_pages(mtd, this, startpage, page - startpage,
                                                oobbuf, oobsel, chipnr, (eccbuf != NULL));
                        if (ret) {
                                DEBUG(MTD_DEBUG_LEVEL0, "nand_write: verify_pages failed %d\n", ret);
                                goto out;
                        }
                        *retlen = written;

                        ofs = autoplace ? mtd->oobavail : mtd->oobsize;
                        if (eccbuf)
                                eccbuf += (page - startpage) * ofs;
                        totalpages -= page - startpage;
                        numpages = min(totalpages, ppblock);
                        page &= chip->pagemask;
                        startpage = page;
                        oobbuf = nand_prepare_oobbuf(mtd, eccbuf, oobsel, autoplace, numpages);
                        oob = 0;
                        /* Check, if we cross a chip boundary */
                        if (!page) {
                                chipnr++;
                                chip->select_chip(mtd, -1);
                                chip->select_chip(mtd, chipnr);
                        }
                }
        }
        /* Verify the remaining pages */
 cmp:
        chip->data_poi = bufstart;
        ret = nand_verify_pages(mtd, this, startpage, totalpages, oobbuf, oobsel, chipnr, (eccbuf != NULL));
        if (!ret)
                *retlen = written;
        else
                DEBUG(MTD_DEBUG_LEVEL0, "nand_write: verify_pages failed %d\n", ret);

 out:
        /* Deselect and wake up anyone waiting on the device */
        nand_release_device(mtd);

        return ret;
}


/**
 * nand_write_oob - [MTD Interface] NAND write out-of-band
 * @mtd:        MTD device structure
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @retlen:     pointer to variable to store the number of written bytes
 * @buf:        the data to write
 *
 * NAND write out-of-band
 */
static int nand_write_oob(struct mtd_info *mtd, loff_t to, size_t len,
                          size_t *retlen, const uint8_t *buf)
{
        int column, page, status, ret = -EIO, chipnr;
        struct nand_chip *chip = mtd->priv;

        DEBUG(MTD_DEBUG_LEVEL3, "nand_write_oob: to = 0x%08x, len = %i\n",
              (unsigned int)to, (int)len);

        /* Initialize return length value */
        *retlen = 0;

        /* Do not allow write past end of page */
        column = to & (mtd->oobsize - 1);
        if ((column + len) > mtd->oobsize) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_write_oob: "
                      "Attempt to write past end of page\n");
                return -EINVAL;
        }

        nand_get_device(chip, mtd, FL_WRITING);

        chipnr = (int)(to >> chip->chip_shift);
        chip->select_chip(mtd, chipnr);

        /* Shift to get page */
        page = (int)(to >> chip->page_shift);

        /*
         * Reset the chip. Some chips (like the Toshiba TC5832DC found in one
         * of my DiskOnChip 2000 test units) will clear the whole data page too
         * if we don't do this. I have no clue why, but I seem to have 'fixed'
         * it in the doc2000 driver in August 1999.  dwmw2.
         */
        chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);

        /* Check, if it is write protected */
        if (nand_check_wp(mtd))
                goto out;

        /* Invalidate the page cache, if we write to the cached page */
        if (page == chip->pagebuf)
                chip->pagebuf = -1;

        if (NAND_MUST_PAD(chip)) {
                chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize,
                              page & chip->pagemask);
                /* prepad 0xff for partial programming */
                chip->write_buf(mtd, ffchars, column);
                /* write data */
                chip->write_buf(mtd, buf, len);
                /* postpad 0xff for partial programming */
                chip->write_buf(mtd, ffchars, mtd->oobsize - (len + column));
        } else {
                chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize + column,
                              page & chip->pagemask);
                chip->write_buf(mtd, buf, len);
        }
        /* Send command to program the OOB data */
        chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);

        status = chip->waitfunc(mtd, chip, FL_WRITING);

        /* See if device thinks it succeeded */
        if (status & NAND_STATUS_FAIL) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_write_oob: "
                      "Failed write, page 0x%08x\n", page);
                ret = -EIO;
                goto out;
        }
        *retlen = len;

#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
        /* Send command to read back the data */
        chip->cmdfunc(mtd, NAND_CMD_READOOB, column, page & chip->pagemask);

        if (chip->verify_buf(mtd, buf, len)) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_write_oob: "
                      "Failed write verify, page 0x%08x\n", page);
                ret = -EIO;
                goto out;
        }
#endif
        ret = 0;
 out:
        /* Deselect and wake up anyone waiting on the device */
        nand_release_device(mtd);

        return ret;
}

/**
 * single_erease_cmd - [GENERIC] NAND standard block erase command function
 * @mtd:        MTD device structure
 * @page:       the page address of the block which will be erased
 *
 * Standard erase command for NAND chips
 */
static void single_erase_cmd(struct mtd_info *mtd, int page)
{
        struct nand_chip *chip = mtd->priv;
        /* Send commands to erase a block */
        chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
        chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
}

/**
 * multi_erease_cmd - [GENERIC] AND specific block erase command function
 * @mtd:        MTD device structure
 * @page:       the page address of the block which will be erased
 *
 * AND multi block erase command function
 * Erase 4 consecutive blocks
 */
static void multi_erase_cmd(struct mtd_info *mtd, int page)
{
        struct nand_chip *chip = mtd->priv;
        /* Send commands to erase a block */
        chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page++);
        chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page++);
        chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page++);
        chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
        chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
}

/**
 * nand_erase - [MTD Interface] erase block(s)
 * @mtd:        MTD device structure
 * @instr:      erase instruction
 *
 * Erase one ore more blocks
 */
static int nand_erase(struct mtd_info *mtd, struct erase_info *instr)
{
        return nand_erase_nand(mtd, instr, 0);
}

#define BBT_PAGE_MASK   0xffffff3f
/**
 * nand_erase_nand - [Internal] erase block(s)
 * @mtd:        MTD device structure
 * @instr:      erase instruction
 * @allowbbt:   allow erasing the bbt area
 *
 * Erase one ore more blocks
 */
int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
                    int allowbbt)
{
        int page, len, status, pages_per_block, ret, chipnr;
        struct nand_chip *chip = mtd->priv;
        int rewrite_bbt[NAND_MAX_CHIPS]={0};
        unsigned int bbt_masked_page = 0xffffffff;

        DEBUG(MTD_DEBUG_LEVEL3, "nand_erase: start = 0x%08x, len = %i\n",
              (unsigned int)instr->addr, (unsigned int)instr->len);

        /* Start address must align on block boundary */
        if (instr->addr & ((1 << chip->phys_erase_shift) - 1)) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_erase: Unaligned address\n");
                return -EINVAL;
        }

        /* Length must align on block boundary */
        if (instr->len & ((1 << chip->phys_erase_shift) - 1)) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_erase: "
                      "Length not block aligned\n");
                return -EINVAL;
        }

        /* Do not allow erase past end of device */
        if ((instr->len + instr->addr) > mtd->size) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_erase: "
                      "Erase past end of device\n");
                return -EINVAL;
        }

        instr->fail_addr = 0xffffffff;

        /* Grab the lock and see if the device is available */
        nand_get_device(chip, mtd, FL_ERASING);

        /* Shift to get first page */
        page = (int)(instr->addr >> chip->page_shift);
        chipnr = (int)(instr->addr >> chip->chip_shift);

        /* Calculate pages in each block */
        pages_per_block = 1 << (chip->phys_erase_shift - chip->page_shift);

        /* Select the NAND device */
        chip->select_chip(mtd, chipnr);

        /* Check, if it is write protected */
        if (nand_check_wp(mtd)) {
                DEBUG(MTD_DEBUG_LEVEL0, "nand_erase: "
                      "Device is write protected!!!\n");
                instr->state = MTD_ERASE_FAILED;
                goto erase_exit;
        }

        /*
         * If BBT requires refresh, set the BBT page mask to see if the BBT
         * should be rewritten. Otherwise the mask is set to 0xffffffff which
         * can not be matched. This is also done when the bbt is actually
         * erased to avoid recusrsive updates
         */
        if (chip->options & BBT_AUTO_REFRESH && !allowbbt)
                bbt_masked_page = chip->bbt_td->pages[chipnr] & BBT_PAGE_MASK;

        /* Loop through the pages */
        len = instr->len;

        instr->state = MTD_ERASING;

        while (len) {
                /*
                 * heck if we have a bad block, we do not erase bad blocks !
                 */
                if (nand_block_checkbad(mtd, ((loff_t) page) <<
                                        chip->page_shift, 0, allowbbt)) {
                        printk(KERN_WARNING "nand_erase: attempt to erase a "
                               "bad block at page 0x%08x\n", page);
                        instr->state = MTD_ERASE_FAILED;
                        goto erase_exit;
                }

                /*
                 * Invalidate the page cache, if we erase the block which
                 * contains the current cached page
                 */
                if (page <= chip->pagebuf && chip->pagebuf <
                    (page + pages_per_block))
                        chip->pagebuf = -1;

                chip->erase_cmd(mtd, page & chip->pagemask);

                status = chip->waitfunc(mtd, chip, FL_ERASING);

                /*
                 * See if operation failed and additional status checks are
                 * available
                 */
                if ((status & NAND_STATUS_FAIL) && (chip->errstat))
                        status = chip->errstat(mtd, chip, FL_ERASING,
                                               status, page);

                /* See if block erase succeeded */
                if (status & NAND_STATUS_FAIL) {
                        DEBUG(MTD_DEBUG_LEVEL0, "nand_erase: "
                              "Failed erase, page 0x%08x\n", page);
                        instr->state = MTD_ERASE_FAILED;
                        instr->fail_addr = (page << chip->page_shift);
                        goto erase_exit;
                }

                /*
                 * If BBT requires refresh, set the BBT rewrite flag to the
                 * page being erased
                 */
                if (bbt_masked_page != 0xffffffff &&
                    (page & BBT_PAGE_MASK) == bbt_masked_page)
                            rewrite_bbt[chipnr] = (page << chip->page_shift);

                /* Increment page address and decrement length */
                len -= (1 << chip->phys_erase_shift);
                page += pages_per_block;

                /* Check, if we cross a chip boundary */
                if (len && !(page & chip->pagemask)) {
                        chipnr++;
                        chip->select_chip(mtd, -1);
                        chip->select_chip(mtd, chipnr);

                        /*
                         * If BBT requires refresh and BBT-PERCHIP, set the BBT
                         * page mask to see if this BBT should be rewritten
                         */
                        if (bbt_masked_page != 0xffffffff &&
                            (chip->bbt_td->options & NAND_BBT_PERCHIP))
                                bbt_masked_page = chip->bbt_td->pages[chipnr] &
                                        BBT_PAGE_MASK;
                }
        }
        instr->state = MTD_ERASE_DONE;

 erase_exit:

        ret = instr->state == MTD_ERASE_DONE ? 0 : -EIO;
        /* Do call back function */
        if (!ret)
                mtd_erase_callback(instr);

        /* Deselect and wake up anyone waiting on the device */
        nand_release_device(mtd);

        /*
         * If BBT requires refresh and erase was successful, rewrite any
         * selected bad block tables
         */
        if (bbt_masked_page == 0xffffffff || ret)
                return ret;

        for (chipnr = 0; chipnr < chip->numchips; chipnr++) {
                if (!rewrite_bbt[chipnr])
                        continue;
                /* update the BBT for chip */
                DEBUG(MTD_DEBUG_LEVEL0, "nand_erase_nand: nand_update_bbt "
                      "(%d:0x%0x 0x%0x)\n", chipnr, rewrite_bbt[chipnr],
                      chip->bbt_td->pages[chipnr]);
                nand_update_bbt(mtd, rewrite_bbt[chipnr]);
        }

        /* Return more or less happy */
        return ret;
}

/**
 * nand_sync - [MTD Interface] sync
 * @mtd:        MTD device structure
 *
 * Sync is actually a wait for chip ready function
 */
static void nand_sync(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;

        DEBUG(MTD_DEBUG_LEVEL3, "nand_sync: called\n");

        /* Grab the lock and see if the device is available */
        nand_get_device(chip, mtd, FL_SYNCING);
        /* Release it and go back */
        nand_release_device(mtd);
}

/**
 * nand_block_isbad - [MTD Interface] Check if block at offset is bad
 * @mtd:        MTD device structure
 * @ofs:        offset relative to mtd start
 */
static int nand_block_isbad(struct mtd_info *mtd, loff_t offs)
{
        /* Check for invalid offset */
        if (offs > mtd->size)
                return -EINVAL;

        return nand_block_checkbad(mtd, offs, 1, 0);
}

/**
 * nand_block_markbad - [MTD Interface] Mark block at the given offset as bad
 * @mtd:        MTD device structure
 * @ofs:        offset relative to mtd start
 */
static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        struct nand_chip *chip = mtd->priv;
        int ret;

        if ((ret = nand_block_isbad(mtd, ofs))) {
                /* If it was bad already, return success and do nothing. */
                if (ret > 0)
                        return 0;
                return ret;
        }

        return chip->block_markbad(mtd, ofs);
}

/**
 * nand_suspend - [MTD Interface] Suspend the NAND flash
 * @mtd:        MTD device structure
 */
static int nand_suspend(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;

        return nand_get_device(chip, mtd, FL_PM_SUSPENDED);
}

/**
 * nand_resume - [MTD Interface] Resume the NAND flash
 * @mtd:        MTD device structure
 */
static void nand_resume(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;

        if (chip->state == FL_PM_SUSPENDED)
                nand_release_device(mtd);
        else
                printk(KERN_ERR "nand_resume() called for a chip which is not "
                       "in suspended state\n");
}

/*
 * Free allocated data structures
 */
static void nand_free_kmem(struct nand_chip *chip)
{
        /* Buffer allocated by nand_scan ? */
        if (chip->options & NAND_OOBBUF_ALLOC)
                kfree(chip->oob_buf);
        /* Buffer allocated by nand_scan ? */
        if (chip->options & NAND_DATABUF_ALLOC)
                kfree(chip->data_buf);
        /* Controller allocated by nand_scan ? */
        if (chip->options & NAND_CONTROLLER_ALLOC)
                kfree(chip->controller);
}

/*
 * Allocate buffers and data structures
 */
static int nand_allocate_kmem(struct mtd_info *mtd, struct nand_chip *chip)
{
        size_t len;

        if (!chip->oob_buf) {
                len = mtd->oobsize <<
                        (chip->phys_erase_shift - chip->page_shift);
                chip->oob_buf = kmalloc(len, GFP_KERNEL);
                if (!chip->oob_buf)
                        goto outerr;
                chip->options |= NAND_OOBBUF_ALLOC;
        }

        if (!chip->data_buf) {
                len = mtd->writesize + mtd->oobsize;
                chip->data_buf = kmalloc(len, GFP_KERNEL);
                if (!chip->data_buf)
                        goto outerr;
                chip->options |= NAND_DATABUF_ALLOC;
        }

        if (!chip->controller) {
                chip->controller = kzalloc(sizeof(struct nand_hw_control),
                                           GFP_KERNEL);
                if (!chip->controller)
                        goto outerr;

                spin_lock_init(&chip->controller->lock);
                init_waitqueue_head(&chip->controller->wq);
                chip->options |= NAND_CONTROLLER_ALLOC;
        }
        return 0;

 outerr:
        printk(KERN_ERR "nand_scan(): Cannot allocate buffers\n");
        nand_free_kmem(chip);
        return -ENOMEM;
}

/*
 * Set default functions
 */
static void nand_set_defaults(struct nand_chip *chip, int busw)
{
        /* check for proper chip_delay setup, set 20us if not */
        if (!chip->chip_delay)
                chip->chip_delay = 20;

        /* check, if a user supplied command function given */
        if (chip->cmdfunc == NULL)
                chip->cmdfunc = nand_command;

        /* check, if a user supplied wait function given */
        if (chip->waitfunc == NULL)
                chip->waitfunc = nand_wait;

        if (!chip->select_chip)
                chip->select_chip = nand_select_chip;
        if (!chip->read_byte)
                chip->read_byte = busw ? nand_read_byte16 : nand_read_byte;
        if (!chip->read_word)
                chip->read_word = nand_read_word;
        if (!chip->block_bad)
                chip->block_bad = nand_block_bad;
        if (!chip->block_markbad)
                chip->block_markbad = nand_default_block_markbad;
        if (!chip->write_buf)
                chip->write_buf = busw ? nand_write_buf16 : nand_write_buf;
        if (!chip->read_buf)
                chip->read_buf = busw ? nand_read_buf16 : nand_read_buf;
        if (!chip->verify_buf)
                chip->verify_buf = busw ? nand_verify_buf16 : nand_verify_buf;
        if (!chip->scan_bbt)
                chip->scan_bbt = nand_default_bbt;
}

/*
 * Get the flash and manufacturer id and lookup if the type is supported
 */
static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
                                                  struct nand_chip *chip,
                                                  int busw, int *maf_id)
{
        struct nand_flash_dev *type = NULL;
        int i, dev_id, maf_idx;

        /* Select the device */
        chip->select_chip(mtd, 0);

        /* Send the command for reading device ID */
        chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

        /* Read manufacturer and device IDs */
        *maf_id = chip->read_byte(mtd);
        dev_id = chip->read_byte(mtd);

        /* Lookup the flash id */
        for (i = 0; nand_flash_ids[i].name != NULL; i++) {
                if (dev_id == nand_flash_ids[i].id) {
                        type =  &nand_flash_ids[i];
                        break;
                }
        }

        if (!type)
                return ERR_PTR(-ENODEV);

        chip->chipsize = nand_flash_ids[i].chipsize << 20;

        /* Newer devices have all the information in additional id bytes */
        if (!nand_flash_ids[i].pagesize) {
                int extid;
                /* The 3rd id byte contains non relevant data ATM */
                extid = chip->read_byte(mtd);
                /* The 4th id byte is the important one */
                extid = chip->read_byte(mtd);
                /* Calc pagesize */
                mtd->writesize = 1024 << (extid & 0x3);
                extid >>= 2;
                /* Calc oobsize */
                mtd->oobsize = (8 << (extid & 0x01)) * (mtd->writesize >> 9);
                extid >>= 2;
                /* Calc blocksize. Blocksize is multiples of 64KiB */
                mtd->erasesize = (64 * 1024) << (extid & 0x03);
                extid >>= 2;
                /* Get buswidth information */
                busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;

        } else {
                /*
                 * Old devices have chip data hardcoded in the device id table
                 */
                mtd->erasesize = nand_flash_ids[i].erasesize;
                mtd->writesize = nand_flash_ids[i].pagesize;
                mtd->oobsize = mtd->writesize / 32;
                busw = nand_flash_ids[i].options & NAND_BUSWIDTH_16;
        }

        /* Try to identify manufacturer */
        for (maf_idx = 0; nand_manuf_ids[maf_idx].id != 0x0; maf_id++) {
                if (nand_manuf_ids[maf_idx].id == *maf_id)
                        break;
        }

        /*
         * Check, if buswidth is correct. Hardware drivers should set
         * chip correct !
         */
        if (busw != (chip->options & NAND_BUSWIDTH_16)) {
                printk(KERN_INFO "NAND device: Manufacturer ID:"
                       " 0x%02x, Chip ID: 0x%02x (%s %s)\n", *maf_id,
                       dev_id, nand_manuf_ids[maf_idx].name, mtd->name);
                printk(KERN_WARNING "NAND bus width %d instead %d bit\n",
                       (chip->options & NAND_BUSWIDTH_16) ? 16 : 8,
                       busw ? 16 : 8);
                return ERR_PTR(-EINVAL);
        }

        /* Calculate the address shift from the page size */
        chip->page_shift = ffs(mtd->writesize) - 1;
        /* Convert chipsize to number of pages per chip -1. */
        chip->pagemask = (chip->chipsize >> chip->page_shift) - 1;

        chip->bbt_erase_shift = chip->phys_erase_shift =
                ffs(mtd->erasesize) - 1;
        chip->chip_shift = ffs(chip->chipsize) - 1;

        /* Set the bad block position */
        chip->badblockpos = mtd->writesize > 512 ?
                NAND_LARGE_BADBLOCK_POS : NAND_SMALL_BADBLOCK_POS;

        /* Get chip options, preserve non chip based options */
        chip->options &= ~NAND_CHIPOPTIONS_MSK;
        chip->options |= nand_flash_ids[i].options & NAND_CHIPOPTIONS_MSK;

        /*
         * Set chip as a default. Board drivers can override it, if necessary
         */
        chip->options |= NAND_NO_AUTOINCR;

        /* Check if chip is a not a samsung device. Do not clear the
         * options for chips which are not having an extended id.
         */
        if (*maf_id != NAND_MFR_SAMSUNG && !nand_flash_ids[i].pagesize)
                chip->options &= ~NAND_SAMSUNG_LP_OPTIONS;

        /* Check for AND chips with 4 page planes */
        if (chip->options & NAND_4PAGE_ARRAY)
                chip->erase_cmd = multi_erase_cmd;
        else
                chip->erase_cmd = single_erase_cmd;

        /* Do not replace user supplied command function ! */
        if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
                chip->cmdfunc = nand_command_lp;

        printk(KERN_INFO "NAND device: Manufacturer ID:"
               " 0x%02x, Chip ID: 0x%02x (%s %s)\n", *maf_id, dev_id,
               nand_manuf_ids[maf_idx].name, type->name);

        return type;
}

/* module_text_address() isn't exported, and it's mostly a pointless
   test if this is a module _anyway_ -- they'd have to try _really_ hard
   to call us from in-kernel code if the core NAND support is modular. */
#ifdef MODULE
#define caller_is_module() (1)
#else
#define caller_is_module() \
        module_text_address((unsigned long)__builtin_return_address(0))
#endif

/**
 * nand_scan - [NAND Interface] Scan for the NAND device
 * @mtd:        MTD device structure
 * @maxchips:   Number of chips to scan for
 *
 * This fills out all the uninitialized function pointers
 * with the defaults.
 * The flash ID is read and the mtd/chip structures are
 * filled with the appropriate values. Buffers are allocated if
 * they are not provided by the board driver
 * The mtd->owner field must be set to the module of the caller
 *
 */
int nand_scan(struct mtd_info *mtd, int maxchips)
{
        int i, busw, nand_maf_id;
        struct nand_chip *chip = mtd->priv;
        struct nand_flash_dev *type;

        /* Many callers got this wrong, so check for it for a while... */
        if (!mtd->owner && caller_is_module()) {
                printk(KERN_CRIT "nand_scan() called with NULL mtd->owner!\n");
                BUG();
        }

        /* Get buswidth to select the correct functions */
        busw = chip->options & NAND_BUSWIDTH_16;
        /* Set the default functions */
        nand_set_defaults(chip, busw);

        /* Read the flash type */
        type = nand_get_flash_type(mtd, chip, busw, &nand_maf_id);

        if (IS_ERR(type)) {
                printk(KERN_WARNING "No NAND device found!!!\n");
                chip->select_chip(mtd, -1);
                return PTR_ERR(type);
        }

        /* Check for a chip array */
        for (i = 1; i < maxchips; i++) {
                chip->select_chip(mtd, i);
                /* Send the command for reading device ID */
                chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
                /* Read manufacturer and device IDs */
                if (nand_maf_id != chip->read_byte(mtd) ||
                    type->id != chip->read_byte(mtd))
                        break;
        }
        if (i > 1)
                printk(KERN_INFO "%d NAND chips detected\n", i);

        /* Store the number of chips and calc total size for mtd */
        chip->numchips = i;
        mtd->size = i * chip->chipsize;

        /* Allocate buffers and data structures */
        if (nand_allocate_kmem(mtd, chip))
                return -ENOMEM;

        /* Preset the internal oob buffer */
        memset(chip->oob_buf, 0xff,
               mtd->oobsize << (chip->phys_erase_shift - chip->page_shift));

        /*
         * If no default placement scheme is given, select an appropriate one
         */
        if (!chip->autooob) {
                switch (mtd->oobsize) {
                case 8:
                        chip->autooob = &nand_oob_8;
                        break;
                case 16:
                        chip->autooob = &nand_oob_16;
                        break;
                case 64:
                        chip->autooob = &nand_oob_64;
                        break;
                default:
                        printk(KERN_WARNING "No oob scheme defined for "
                               "oobsize %d\n", mtd->oobsize);
                        BUG();
                }
        }

        /*
         * The number of bytes available for the filesystem to place fs
         * dependend oob data
         */
        mtd->oobavail = 0;
        for (i = 0; chip->autooob->oobfree[i][1]; i++)
                mtd->oobavail += chip->autooob->oobfree[i][1];

        /*
         * check ECC mode, default to software if 3byte/512byte hardware ECC is
         * selected and we have 256 byte pagesize fallback to software ECC
         */
        switch (chip->ecc.mode) {
        case NAND_ECC_HW:
                /* Use standard hwecc read page function ? */
                if (!chip->ecc.read_page)
                        chip->ecc.read_page = nand_read_page_hwecc;

        case NAND_ECC_HW_SYNDROME:
                if (!chip->ecc.calculate || !chip->ecc.correct ||
                    !chip->ecc.hwctl) {
                        printk(KERN_WARNING "No ECC functions supplied, "
                               "Hardware ECC not possible\n");
                        BUG();
                }
                /* Use standard syndrome read page function ? */
                if (!chip->ecc.read_page)
                        chip->ecc.read_page = nand_read_page_syndrome;

                if (mtd->writesize >= chip->ecc.size)
                        break;
                printk(KERN_WARNING "%d byte HW ECC not possible on "
                       "%d byte page size, fallback to SW ECC\n",
                       chip->ecc.size, mtd->writesize);
                chip->ecc.mode = NAND_ECC_SOFT;

        case NAND_ECC_SOFT:
                chip->ecc.calculate = nand_calculate_ecc;
                chip->ecc.correct = nand_correct_data;
                chip->ecc.read_page = nand_read_page_swecc;
                chip->ecc.size = 256;
                chip->ecc.bytes = 3;
                break;

        case NAND_ECC_NONE:
                printk(KERN_WARNING "NAND_ECC_NONE selected by board driver. "
                       "This is not recommended !!\n");
                chip->ecc.read_page = nand_read_page_swecc;
                chip->ecc.size = mtd->writesize;
                chip->ecc.bytes = 0;
                break;
        default:
                printk(KERN_WARNING "Invalid NAND_ECC_MODE %d\n",
                       chip->ecc.mode);
                BUG();
        }

        /*
         * Set the number of read / write steps for one page depending on ECC
         * mode
         */
        chip->ecc.steps = mtd->writesize / chip->ecc.size;
        if(chip->ecc.steps * chip->ecc.size != mtd->writesize) {
                printk(KERN_WARNING "Invalid ecc parameters\n");
                BUG();
        }
        chip->ecc.total = chip->ecc.steps * chip->ecc.bytes;

        /* Initialize state */
        chip->state = FL_READY;

        /* De-select the device */
        chip->select_chip(mtd, -1);

        /* Invalidate the pagebuffer reference */
        chip->pagebuf = -1;

        /* Fill in remaining MTD driver data */
        mtd->type = MTD_NANDFLASH;
        mtd->flags = MTD_CAP_NANDFLASH;
        mtd->ecctype = MTD_ECC_SW;
        mtd->erase = nand_erase;
        mtd->point = NULL;
        mtd->unpoint = NULL;
        mtd->read = nand_read;
        mtd->write = nand_write;
        mtd->read_oob = nand_read_oob;
        mtd->write_oob = nand_write_oob;
        mtd->sync = nand_sync;
        mtd->lock = NULL;
        mtd->unlock = NULL;
        mtd->suspend = nand_suspend;
        mtd->resume = nand_resume;
        mtd->block_isbad = nand_block_isbad;
        mtd->block_markbad = nand_block_markbad;

        /* and make the autooob the default one */
        memcpy(&mtd->oobinfo, chip->autooob, sizeof(mtd->oobinfo));

        /* Check, if we should skip the bad block table scan */
        if (chip->options & NAND_SKIP_BBTSCAN)
                return 0;

        /* Build bad block table */
        return chip->scan_bbt(mtd);
}

/**
 * nand_release - [NAND Interface] Free resources held by the NAND device
 * @mtd:        MTD device structure
*/
void nand_release(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd->priv;

#ifdef CONFIG_MTD_PARTITIONS
        /* Deregister partitions */
        del_mtd_partitions(mtd);
#endif
        /* Deregister the device */
        del_mtd_device(mtd);

        /* Free bad block table memory */
        kfree(chip->bbt);
        /* Free buffers */
        nand_free_kmem(chip);
}

EXPORT_SYMBOL_GPL(nand_scan);
EXPORT_SYMBOL_GPL(nand_release);

static int __init nand_base_init(void)
{
        led_trigger_register_simple("nand-disk", &nand_led_trigger);
        return 0;
}

static void __exit nand_base_exit(void)
{
        led_trigger_unregister_simple(nand_led_trigger);
}

module_init(nand_base_init);
module_exit(nand_base_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steven J. Hill <sjhill@realitydiluted.com>, Thomas Gleixner <tglx@linutronix.de>");
MODULE_DESCRIPTION("Generic NAND flash driver code");