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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 Thomas Gleixner (tglx@linutronix.de)
 *
 *  02-08-2004  tglx: support for strange chips, which cannot auto increment
 *          pages on read / read_oob
 *
 *  03-17-2004  tglx: Check ready before auto increment check. Simon Bayes
 *          pointed this out, as he marked an auto increment capable chip
 *          as NOAUTOINCR in the board driver.
 *          Make reads over block boundaries work too
 *
 *  04-14-2004    tglx: first working version for 2k page size chips
 *
 *  05-19-2004  tglx: Basic support for Renesas AG-AND chips
 *
 *  09-24-2004  tglx: add support for hardware controllers (e.g. ECC) shared
 *          among multiple independend devices. Suggestions and initial patch
 *          from Ben Dooks <ben-mtd@fluff.org>
 *
 * 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.
 *
 * $Id: nand_base.c,v 1.126 2004/12/13 11:22:25 lavinen Exp $
 *
 * 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.
 *
 */

/* XXX U-BOOT XXX */
#if 0
#include <linux/delay.h>
#include <linux/errno.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 <asm/io.h>

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

#endif

#include <common.h>

#if (CONFIG_COMMANDS & CFG_CMD_NAND) && !defined(CFG_NAND_LEGACY)

#include <malloc.h>
#include <watchdog.h>
#include <linux/mtd/compat.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ecc.h>

#include <asm/io.h>
#include <asm/errno.h>

#ifdef CONFIG_JFFS2_NAND
#include <jffs2/jffs2.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 u_char 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 u_char *buf, int len);
static void nand_read_buf(struct mtd_info *mtd, u_char *buf, int len);
static int nand_verify_buf(struct mtd_info *mtd, const u_char *buf, int len);

static int nand_read (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf);
static int nand_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
                    size_t * retlen, u_char * buf, u_char * eccbuf, struct nand_oobinfo *oobsel);
static int nand_read_oob (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf);
static int nand_write (struct mtd_info *mtd, loff_t to, size_t len, size_t * retlen, const u_char * buf);
static int nand_write_ecc (struct mtd_info *mtd, loff_t to, size_t len,
                     size_t * retlen, const u_char * buf, u_char * eccbuf, struct nand_oobinfo *oobsel);
static int nand_write_oob (struct mtd_info *mtd, loff_t to, size_t len, size_t * retlen, const u_char *buf);
/* XXX U-BOOT XXX */
#if 0
static int nand_writev (struct mtd_info *mtd, const struct kvec *vecs,
                  unsigned long count, loff_t to, size_t * retlen);
static int nand_writev_ecc (struct mtd_info *mtd, const struct kvec *vecs,
                  unsigned long count, loff_t to, size_t * retlen, u_char *eccbuf, struct nand_oobinfo *oobsel);
#endif
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 *this, int page, u_char *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 *this, int page, int numpages,
      u_char *oob_buf, struct nand_oobinfo *oobsel, int chipnr, int oobmode);
#else
#define nand_verify_pages(...) (0)
#endif

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

/**
 * nand_release_device - [GENERIC] release chip
 * @mtd:    MTD device structure
 *
 * Deselect, release chip lock and wake up anyone waiting on the device
 */
/* XXX U-BOOT XXX */
#if 0
static void nand_release_device (struct mtd_info *mtd)
{
      struct nand_chip *this = mtd->priv;

      /* De-select the NAND device */
      this->select_chip(mtd, -1);
      /* Do we have a hardware controller ? */
      if (this->controller) {
            spin_lock(&this->controller->lock);
            this->controller->active = NULL;
            spin_unlock(&this->controller->lock);
      }
      /* Release the chip */
      spin_lock (&this->chip_lock);
      this->state = FL_READY;
      wake_up (&this->wq);
      spin_unlock (&this->chip_lock);
}
#else
static void nand_release_device (struct mtd_info *mtd)
{
      struct nand_chip *this = mtd->priv;
      this->select_chip(mtd, -1);   /* De-select the NAND device */
}
#endif

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

/**
 * nand_write_byte - [DEFAULT] write one byte to the chip
 * @mtd:    MTD device structure
 * @byte:   pointer to data byte to write
 *
 * Default write function for 8it buswith
 */
static void nand_write_byte(struct mtd_info *mtd, u_char byte)
{
      struct nand_chip *this = mtd->priv;
      writeb(byte, this->IO_ADDR_W);
}

/**
 * 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 u_char nand_read_byte16(struct mtd_info *mtd)
{
      struct nand_chip *this = mtd->priv;
      return (u_char) cpu_to_le16(readw(this->IO_ADDR_R));
}

/**
 * nand_write_byte16 - [DEFAULT] write one byte endianess aware to the chip
 * @mtd:    MTD device structure
 * @byte:   pointer to data byte to write
 *
 * Default write function for 16bit buswith with
 * endianess conversion
 */
static void nand_write_byte16(struct mtd_info *mtd, u_char byte)
{
      struct nand_chip *this = mtd->priv;
      writew(le16_to_cpu((u16) byte), this->IO_ADDR_W);
}

/**
 * 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 *this = mtd->priv;
      return readw(this->IO_ADDR_R);
}

/**
 * nand_write_word - [DEFAULT] write one word to the chip
 * @mtd:    MTD device structure
 * @word:   data word to write
 *
 * Default write function for 16bit buswith without
 * endianess conversion
 */
static void nand_write_word(struct mtd_info *mtd, u16 word)
{
      struct nand_chip *this = mtd->priv;
      writew(word, this->IO_ADDR_W);
}

/**
 * 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 chip)
{
      struct nand_chip *this = mtd->priv;
      switch(chip) {
      case -1:
            this->hwcontrol(mtd, NAND_CTL_CLRNCE);
            break;
      case 0:
            this->hwcontrol(mtd, NAND_CTL_SETNCE);
            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 u_char *buf, int len)
{
      int i;
      struct nand_chip *this = mtd->priv;

      for (i=0; i<len; i++)
            writeb(buf[i], this->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, u_char *buf, int len)
{
      int i;
      struct nand_chip *this = mtd->priv;

      for (i=0; i<len; i++)
            buf[i] = readb(this->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 u_char *buf, int len)
{
      int i;
      struct nand_chip *this = mtd->priv;

      for (i=0; i<len; i++)
            if (buf[i] != readb(this->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 u_char *buf, int len)
{
      int i;
      struct nand_chip *this = mtd->priv;
      u16 *p = (u16 *) buf;
      len >>= 1;

      for (i=0; i<len; i++)
            writew(p[i], this->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, u_char *buf, int len)
{
      int i;
      struct nand_chip *this = mtd->priv;
      u16 *p = (u16 *) buf;
      len >>= 1;

      for (i=0; i<len; i++)
            p[i] = readw(this->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 u_char *buf, int len)
{
      int i;
      struct nand_chip *this = mtd->priv;
      u16 *p = (u16 *) buf;
      len >>= 1;

      for (i=0; i<len; i++)
            if (p[i] != readw(this->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 *this = mtd->priv;
      u16 bad;

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

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

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

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

      if (getchip) {
            /* Deselect and wake up anyone waiting on the device */
            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 *this = mtd->priv;
      u_char buf[2] = {0, 0};
      size_t      retlen;
      int block;

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

      /* Do we have a flash based bad block table ? */
      if (this->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 + (this->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 *this = mtd->priv;
      /* Check the WP bit */
      this->cmdfunc (mtd, NAND_CMD_STATUS, -1, -1);
      return (this->read_byte(mtd) & 0x80) ? 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 *this = mtd->priv;

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

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

/**
 * 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 command, int column, int page_addr)
{
      register struct nand_chip *this = mtd->priv;

      /* Begin command latch cycle */
      this->hwcontrol(mtd, NAND_CTL_SETCLE);
      /*
       * Write out the command to the device.
       */
      if (command == NAND_CMD_SEQIN) {
            int readcmd;

            if (column >= mtd->oobblock) {
                  /* OOB area */
                  column -= mtd->oobblock;
                  readcmd = NAND_CMD_READOOB;
            } else if (column < 256) {
                  /* First 256 bytes --> READ0 */
                  readcmd = NAND_CMD_READ0;
            } else {
                  column -= 256;
                  readcmd = NAND_CMD_READ1;
            }
            this->write_byte(mtd, readcmd);
      }
      this->write_byte(mtd, command);

      /* Set ALE and clear CLE to start address cycle */
      this->hwcontrol(mtd, NAND_CTL_CLRCLE);

      if (column != -1 || page_addr != -1) {
            this->hwcontrol(mtd, NAND_CTL_SETALE);

            /* Serially input address */
            if (column != -1) {
                  /* Adjust columns for 16 bit buswidth */
                  if (this->options & NAND_BUSWIDTH_16)
                        column >>= 1;
                  this->write_byte(mtd, column);
            }
            if (page_addr != -1) {
                  this->write_byte(mtd, (unsigned char) (page_addr & 0xff));
                  this->write_byte(mtd, (unsigned char) ((page_addr >> 8) & 0xff));
                  /* One more address cycle for devices > 32MiB */
                  if (this->chipsize > (32 << 20))
                        this->write_byte(mtd, (unsigned char) ((page_addr >> 16) & 0x0f));
            }
            /* Latch in address */
            this->hwcontrol(mtd, NAND_CTL_CLRALE);
      }

      /*
       * 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:
            return;

      case NAND_CMD_RESET:
            if (this->dev_ready)
                  break;
            udelay(this->chip_delay);
            this->hwcontrol(mtd, NAND_CTL_SETCLE);
            this->write_byte(mtd, NAND_CMD_STATUS);
            this->hwcontrol(mtd, NAND_CTL_CLRCLE);
            while ( !(this->read_byte(mtd) & 0x40));
            return;

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

      /* Apply this short delay always to ensure that we do wait tWB in
       * any case on any machine. */
      ndelay (100);
      /* wait until command is processed */
      while (!this->dev_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 seperate 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 command, int column, int page_addr)
{
      register struct nand_chip *this = mtd->priv;

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


      /* Begin command latch cycle */
      this->hwcontrol(mtd, NAND_CTL_SETCLE);
      /* Write out the command to the device. */
      this->write_byte(mtd, command);
      /* End command latch cycle */
      this->hwcontrol(mtd, NAND_CTL_CLRCLE);

      if (column != -1 || page_addr != -1) {
            this->hwcontrol(mtd, NAND_CTL_SETALE);

            /* Serially input address */
            if (column != -1) {
                  /* Adjust columns for 16 bit buswidth */
                  if (this->options & NAND_BUSWIDTH_16)
                        column >>= 1;
                  this->write_byte(mtd, column & 0xff);
                  this->write_byte(mtd, column >> 8);
            }
            if (page_addr != -1) {
                  this->write_byte(mtd, (unsigned char) (page_addr & 0xff));
                  this->write_byte(mtd, (unsigned char) ((page_addr >> 8) & 0xff));
                  /* One more address cycle for devices > 128MiB */
                  if (this->chipsize > (128 << 20))
                        this->write_byte(mtd, (unsigned char) ((page_addr >> 16) & 0xff));
            }
            /* Latch in address */
            this->hwcontrol(mtd, NAND_CTL_CLRALE);
      }

      /*
       * program and erase have their own busy handlers
       * status and sequential in needs 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:
            return;


      case NAND_CMD_RESET:
            if (this->dev_ready)
                  break;
            udelay(this->chip_delay);
            this->hwcontrol(mtd, NAND_CTL_SETCLE);
            this->write_byte(mtd, NAND_CMD_STATUS);
            this->hwcontrol(mtd, NAND_CTL_CLRCLE);
            while ( !(this->read_byte(mtd) & 0x40));
            return;

      case NAND_CMD_READ0:
            /* Begin command latch cycle */
            this->hwcontrol(mtd, NAND_CTL_SETCLE);
            /* Write out the start read command */
            this->write_byte(mtd, NAND_CMD_READSTART);
            /* End command latch cycle */
            this->hwcontrol(mtd, NAND_CTL_CLRCLE);
            /* Fall through into ready check */

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

      /* Apply this short delay always to ensure that we do wait tWB in
       * any case on any machine. */
      ndelay (100);
      /* wait until command is processed */
      while (!this->dev_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
 */
/* XXX U-BOOT XXX */
#if 0
static void nand_get_device (struct nand_chip *this, struct mtd_info *mtd, int new_state)
{
      struct nand_chip *active = this;

      DECLARE_WAITQUEUE (wait, current);

      /*
       * Grab the lock and see if the device is available
      */
retry:
      /* Hardware controller shared among independend devices */
      if (this->controller) {
            spin_lock (&this->controller->lock);
            if (this->controller->active)
                  active = this->controller->active;
            else
                  this->controller->active = this;
            spin_unlock (&this->controller->lock);
      }

      if (active == this) {
            spin_lock (&this->chip_lock);
            if (this->state == FL_READY) {
                  this->state = new_state;
                  spin_unlock (&this->chip_lock);
                  return;
            }
      }
      set_current_state (TASK_UNINTERRUPTIBLE);
      add_wait_queue (&active->wq, &wait);
      spin_unlock (&active->chip_lock);
      schedule ();
      remove_wait_queue (&active->wq, &wait);
      goto retry;
}
#else
static void nand_get_device (struct nand_chip *this, struct mtd_info *mtd, int new_state) {}
#endif

/**
 * 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
 *
*/
/* XXX U-BOOT XXX */
#if 0
static int nand_wait(struct mtd_info *mtd, struct nand_chip *this, int state)
{
      unsigned long     timeo = jiffies;
      int   status;

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

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

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

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

            if (this->dev_ready) {
                  if (this->dev_ready(mtd))
                        break;
            } else {
                  if (this->read_byte(mtd) & NAND_STATUS_READY)
                        break;
            }
            yield ();
      }
      status = (int) this->read_byte(mtd);
      return status;

      return 0;
}
#else
static int nand_wait(struct mtd_info *mtd, struct nand_chip *this, int state)
{
      unsigned long     timeo;

      if (state == FL_ERASING)
            timeo = CFG_HZ * 400;
      else
            timeo = CFG_HZ * 20;

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

      reset_timer();

      while (1) {
            if (get_timer(0) > timeo) {
                  printf("Timeout!");
                  return 0;
                  }

            if (this->dev_ready) {
                  if (this->dev_ready(mtd))
                        break;
            } else {
                  if (this->read_byte(mtd) & NAND_STATUS_READY)
                        break;
            }
      }
#ifdef PPCHAMELON_NAND_TIMER_HACK
      reset_timer();
      while (get_timer(0) < 10);
#endif /*  PPCHAMELON_NAND_TIMER_HACK */

      return this->read_byte(mtd);
}
#endif

/**
 * 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 & this->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 *this, int page,
      u_char *oob_buf,  struct nand_oobinfo *oobsel, int cached)
{
      int   i, status;
      u_char      ecc_code[32];
      int   eccmode = oobsel->useecc ? this->eccmode : NAND_ECC_NONE;
      uint        *oob_config = oobsel->eccpos;
      int   datidx = 0, eccidx = 0, eccsteps = this->eccsteps;
      int   eccbytes = 0;

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

      /* Send command to begin auto page programming */
      this->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");
            this->write_buf(mtd, this->data_poi, mtd->oobblock);
            break;

      /* Software ecc 3/256, write all */
      case NAND_ECC_SOFT:
            for (; eccsteps; eccsteps--) {
                  this->calculate_ecc(mtd, &this->data_poi[datidx], ecc_code);
                  for (i = 0; i < 3; i++, eccidx++)
                        oob_buf[oob_config[eccidx]] = ecc_code[i];
                  datidx += this->eccsize;
            }
            this->write_buf(mtd, this->data_poi, mtd->oobblock);
            break;
      default:
            eccbytes = this->eccbytes;
            for (; eccsteps; eccsteps--) {
                  /* enable hardware ecc logic for write */
                  this->enable_hwecc(mtd, NAND_ECC_WRITE);
                  this->write_buf(mtd, &this->data_poi[datidx], this->eccsize);
                  this->calculate_ecc(mtd, &this->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 (this->options & NAND_HWECC_SYNDROME)
                        this->write_buf(mtd, ecc_code, eccbytes);
                  datidx += this->eccsize;
            }
            break;
      }

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

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

      if (!cached) {
            /* call wait ready function */
            status = this->waitfunc (mtd, this, FL_WRITING);
            /* See if device thinks it succeeded */
            if (status & 0x01) {
                  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 = this->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 & this->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 *this, int page, int numpages,
      u_char *oob_buf, struct nand_oobinfo *oobsel, int chipnr, int oobmode)
{
      int   i, j, datidx = 0, oobofs = 0, res = -EIO;
      int   eccsteps = this->eccsteps;
      int   hweccbytes;
      u_char      oobdata[64];

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

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

      for(;;) {
            for (j = 0; j < eccsteps; j++) {
                  /* Loop through and verify the data */
                  if (this->verify_buf(mtd, &this->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 (this->verify_buf(mtd, &this->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 (this->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 */
                  this->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 (!this->dev_ready)
                  udelay (this->chip_delay);
            else
                  while (!this->dev_ready(mtd));

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


            /* Check, if the chip supports auto page increment */
            if (!NAND_CANAUTOINCR(this))
                  this->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:
      this->cmdfunc (mtd, NAND_CMD_RESET, -1, -1);
      return res;
}
#endif

/**
 * nand_read - [MTD Interface] MTD compability function for nand_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
 *
 * This function simply calls nand_read_ecc with oob buffer and oobsel = NULL
*/
static int nand_read (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf)
{
      return nand_read_ecc (mtd, from, len, retlen, buf, NULL, NULL);
}


/**
 * nand_read_ecc - [MTD Interface] 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
 * @oob_buf:      filesystem supplied oob data buffer
 * @oobsel: oob selection structure
 *
 * NAND read with ECC
 */
static int nand_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
                    size_t * retlen, u_char * buf, u_char * oob_buf, struct nand_oobinfo *oobsel)
{
      int i, j, col, realpage, page, end, ecc, chipnr, sndcmd = 1;
      int read = 0, oob = 0, ecc_status = 0, ecc_failed = 0;
      struct nand_chip *this = mtd->priv;
      u_char *data_poi, *oob_data = oob_buf;
      u_char ecc_calc[32];
      u_char ecc_code[32];
      int eccmode, eccsteps;
      unsigned *oob_config;
      int   datidx;
      int   blockcheck = (1 << (this->phys_erase_shift - this->page_shift)) - 1;
      int   eccbytes;
      int   compareecc = 1;
      int   oobreadlen;


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

      /* Do not allow reads past end of device */
      if ((from + len) > mtd->size) {
            DEBUG (MTD_DEBUG_LEVEL0, "nand_read_ecc: Attempt read beyond end of device\n");
            *retlen = 0;
            return -EINVAL;
      }

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

      /* use userspace supplied oobinfo, if zero */
      if (oobsel == NULL)
            oobsel = &mtd->oobinfo;

      /* Autoplace of oob data ? Use the default placement scheme */
      if (oobsel->useecc == MTD_NANDECC_AUTOPLACE)
            oobsel = this->autooob;

      eccmode = oobsel->useecc ? this->eccmode : NAND_ECC_NONE;
      oob_config = oobsel->eccpos;

      /* Select the NAND device */
      chipnr = (int)(from >> this->chip_shift);
      this->select_chip(mtd, chipnr);

      /* First we calculate the starting page */
      realpage = (int) (from >> this->page_shift);
      page = realpage & this->pagemask;

      /* Get raw starting column */
      col = from & (mtd->oobblock - 1);

      end = mtd->oobblock;
      ecc = this->eccsize;
      eccbytes = this->eccbytes;

      if ((eccmode == NAND_ECC_NONE) || (this->options & NAND_HWECC_SYNDROME))
            compareecc = 0;

      oobreadlen = mtd->oobsize;
      if (this->options & NAND_HWECC_SYNDROME)
            oobreadlen -= oobsel->eccbytes;

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

            int aligned = (!col && (len - read) >= end);
            /*
             * If the read is not page aligned, we have to read into data buffer
             * due to ecc, else we read into return buffer direct
             */
            if (aligned)
                  data_poi = &buf[read];
            else
                  data_poi = this->data_buf;

            /* Check, if we have this page in the buffer
             *
             * FIXME: Make it work when we must provide oob data too,
             * check the usage of data_buf oob field
             */
            if (realpage == this->pagebuf && !oob_buf) {
                  /* aligned read ? */
                  if (aligned)
                        memcpy (data_poi, this->data_buf, end);
                  goto readdata;
            }

            /* Check, if we must send the read command */
            if (sndcmd) {
                  this->cmdfunc (mtd, NAND_CMD_READ0, 0x00, page);
                  sndcmd = 0;
            }

            /* get oob area, if we have no oob buffer from fs-driver */
            if (!oob_buf || oobsel->useecc == MTD_NANDECC_AUTOPLACE ||
                  oobsel->useecc == MTD_NANDECC_AUTOPL_USR)
                  oob_data = &this->data_buf[end];

            eccsteps = this->eccsteps;

            switch (eccmode) {
            case NAND_ECC_NONE: {   /* No ECC, Read in a page */
/* XXX U-BOOT XXX */
#if 0
                  static unsigned long lastwhinge = 0;
                  if ((lastwhinge / HZ) != (jiffies / HZ)) {
                        printk (KERN_WARNING "Reading data from NAND FLASH without ECC is not recommended\n");
                        lastwhinge = jiffies;
                  }
#else
                  puts("Reading data from NAND FLASH without ECC is not recommended\n");
#endif
                  this->read_buf(mtd, data_poi, end);
                  break;
            }

            case NAND_ECC_SOFT:     /* Software ECC 3/256: Read in a page + oob data */
                  this->read_buf(mtd, data_poi, end);
                  for (i = 0, datidx = 0; eccsteps; eccsteps--, i+=3, datidx += ecc)
                        this->calculate_ecc(mtd, &data_poi[datidx], &ecc_calc[i]);
                  break;

            default:
                  for (i = 0, datidx = 0; eccsteps; eccsteps--, i+=eccbytes, datidx += ecc) {
                        this->enable_hwecc(mtd, NAND_ECC_READ);
                        this->read_buf(mtd, &data_poi[datidx], ecc);

                        /* HW ecc with syndrome calculation must read the
                         * syndrome from flash immidiately after the data */
                        if (!compareecc) {
                              /* Some hw ecc generators need to know when the
                               * syndrome is read from flash */
                              this->enable_hwecc(mtd, NAND_ECC_READSYN);
                              this->read_buf(mtd, &oob_data[i], eccbytes);
                              /* We calc error correction directly, it checks the hw
                               * generator for an error, reads back the syndrome and
                               * does the error correction on the fly */
                              if (this->correct_data(mtd, &data_poi[datidx], &oob_data[i], &ecc_code[i]) == -1) {
                                    DEBUG (MTD_DEBUG_LEVEL0, "nand_read_ecc: "
                                          "Failed ECC read, page 0x%08x on chip %d\n", page, chipnr);
                                    ecc_failed++;
                              }
                        } else {
                              this->calculate_ecc(mtd, &data_poi[datidx], &ecc_calc[i]);
                        }
                  }
                  break;
            }

            /* read oobdata */
            this->read_buf(mtd, &oob_data[mtd->oobsize - oobreadlen], oobreadlen);

            /* Skip ECC check, if not requested (ECC_NONE or HW_ECC with syndromes) */
            if (!compareecc)
                  goto readoob;

            /* Pick the ECC bytes out of the oob data */
            for (j = 0; j < oobsel->eccbytes; j++)
                  ecc_code[j] = oob_data[oob_config[j]];

            /* correct data, if neccecary */
            for (i = 0, j = 0, datidx = 0; i < this->eccsteps; i++, datidx += ecc) {
                  ecc_status = this->correct_data(mtd, &data_poi[datidx], &ecc_code[j], &ecc_calc[j]);

                  /* Get next chunk of ecc bytes */
                  j += eccbytes;

                  /* Check, if we have a fs supplied oob-buffer,
                   * This is the legacy mode. Used by YAFFS1
                   * Should go away some day
                   */
                  if (oob_buf && oobsel->useecc == MTD_NANDECC_PLACE) {
                        int *p = (int *)(&oob_data[mtd->oobsize]);
                        p[i] = ecc_status;
                  }

                  if (ecc_status == -1) {
                        DEBUG (MTD_DEBUG_LEVEL0, "nand_read_ecc: " "Failed ECC read, page 0x%08x\n", page);
                        ecc_failed++;
                  }
            }

      readoob:
            /* check, if we have a fs supplied oob-buffer */
            if (oob_buf) {
                  /* without autoplace. Legacy mode used by YAFFS1 */
                  switch(oobsel->useecc) {
                  case MTD_NANDECC_AUTOPLACE:
                  case MTD_NANDECC_AUTOPL_USR:
                        /* Walk through the autoplace chunks */
                        for (i = 0, j = 0; j < mtd->oobavail; i++) {
                              int from = oobsel->oobfree[i][0];
                              int num = oobsel->oobfree[i][1];
                              memcpy(&oob_buf[oob], &oob_data[from], num);
                              j+= num;
                        }
                        oob += mtd->oobavail;
                        break;
                  case MTD_NANDECC_PLACE:
                        /* YAFFS1 legacy mode */
                        oob_data += this->eccsteps * sizeof (int);
                  default:
                        oob_data += mtd->oobsize;
                  }
            }
      readdata:
            /* Partial page read, transfer data into fs buffer */
            if (!aligned) {
                  for (j = col; j < end && read < len; j++)
                        buf[read++] = data_poi[j];
                  this->pagebuf = realpage;
            } else
                  read += mtd->oobblock;

            /* 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 (!this->dev_ready)
                  udelay (this->chip_delay);
            else
                  while (!this->dev_ready(mtd));

            if (read == len)
                  break;

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

            page = realpage & this->pagemask;
            /* Check, if we cross a chip boundary */
            if (!page) {
                  chipnr++;
                  this->select_chip(mtd, -1);
                  this->select_chip(mtd, chipnr);
            }
            /* Check, if the chip supports auto page increment
             * or if we have hit a block boundary.
            */
            if (!NAND_CANAUTOINCR(this) || !(page & blockcheck))
                  sndcmd = 1;
      }

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

      /*
       * Return success, if no ECC failures, else -EBADMSG
       * fs driver will take care of that, because
       * retlen == desired len and result == -EBADMSG
       */
      *retlen = read;
      return ecc_failed ? -EBADMSG : 0;
}

/**
 * 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, u_char * buf)
{
      int i, col, page, chipnr;
      struct nand_chip *this = mtd->priv;
      int   blockcheck = (1 << (this->phys_erase_shift - this->page_shift)) - 1;

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

      /* Shift to get page */
      page = (int)(from >> this->page_shift);
      chipnr = (int)(from >> this->chip_shift);

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

      /* 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");
            *retlen = 0;
            return -EINVAL;
      }

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

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

      /* Send the read command */
      this->cmdfunc (mtd, NAND_CMD_READOOB, col, page & this->pagemask);
      /*
       * Read the data, if we read more than one page
       * oob data, let the device transfer the data !
       */
      i = 0;
      while (i < len) {
            int thislen = mtd->oobsize - col;
            thislen = min_t(int, thislen, len);
            this->read_buf(mtd, &buf[i], thislen);
            i += thislen;

            /* 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 (!this->dev_ready)
                  udelay (this->chip_delay);
            else
                  while (!this->dev_ready(mtd));

            /* Read more ? */
            if (i < len) {
                  page++;
                  col = 0;

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

                  /* Check, if the chip supports auto page increment
                   * or if we have hit a block boundary.
                  */
                  if (!NAND_CANAUTOINCR(this) || !(page & blockcheck)) {
                        /* For subsequent page reads set offset to 0 */
                        this->cmdfunc (mtd, NAND_CMD_READOOB, 0x0, page & this->pagemask);
                  }
            }
      }

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

      /* Return happy */
      *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 *this = mtd->priv;
      int page = (int) (from >> this->page_shift);
      int chip = (int) (from >> this->chip_shift);
      int sndcmd = 1;
      int cnt = 0;
      int pagesize = mtd->oobblock + mtd->oobsize;
      int   blockcheck = (1 << (this->phys_erase_shift - this->page_shift)) - 1;

      /* 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 (this, mtd , FL_READING);

      this->select_chip (mtd, chip);

      /* Add requested oob length */
      len += ooblen;

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

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

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

            if (!this->dev_ready)
                  udelay (this->chip_delay);
            else
                  while (!this->dev_ready(mtd));

            /* Check, if the chip supports auto page increment */
            if (!NAND_CANAUTOINCR(this) || !(page & blockcheck))
                  sndcmd = 1;
      }

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


/**
 * 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 u_char * nand_prepare_oobbuf (struct mtd_info *mtd, u_char *fsbuf, struct nand_oobinfo *oobsel,
            int autoplace, int numpages)
{
      struct nand_chip *this = 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 (this->oobdirty) {
            memset (this->oob_buf, 0xff,
                  mtd->oobsize << (this->phys_erase_shift - this->page_shift));
            this->oobdirty = 0;
      }

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

      /* Walk through the pages and place the data */
      this->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 (&this->oob_buf[to], fsbuf, num);
                  len += num;
                  fsbuf += num;
            }
            ofs += mtd->oobavail;
      }
      return this->oob_buf;
}

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

/**
 * nand_write - [MTD Interface] compability function for nand_write_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
 *
 * This function simply calls nand_write_ecc with oob buffer and oobsel = NULL
 *
*/
static int nand_write (struct mtd_info *mtd, loff_t to, size_t len, size_t * retlen, const u_char * buf)
{
      return (nand_write_ecc (mtd, to, len, retlen, buf, NULL, NULL));
}

/**
 * nand_write_ecc - [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
 * @eccbuf: filesystem supplied oob data buffer
 * @oobsel: oob selection structure
 *
 * NAND write with ECC
 */
static int nand_write_ecc (struct mtd_info *mtd, loff_t to, size_t len,
                     size_t * retlen, const u_char * buf, u_char * eccbuf, struct nand_oobinfo *oobsel)
{
      int startpage, page, ret = -EIO, oob = 0, written = 0, chipnr;
      int autoplace = 0, numpages, totalpages;
      struct nand_chip *this = mtd->priv;
      u_char *oobbuf, *bufstart;
      int   ppblock = (1 << (this->phys_erase_shift - this->page_shift));

      DEBUG (MTD_DEBUG_LEVEL3, "nand_write_ecc: 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_ecc: 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_ecc: Attempt to write not page aligned data\n");
            return -EINVAL;
      }

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

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

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

      /* if oobsel is NULL, use chip defaults */
      if (oobsel == NULL)
            oobsel = &mtd->oobinfo;

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

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

      /* Set it relative to chip */
      page &= this->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 = (u_char *)buf;

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

            this->data_poi = (u_char*) &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, this, page, &oobbuf[oob], oobsel, (--numpages > 0));
            if (ret) {
                  DEBUG (MTD_DEBUG_LEVEL0, "nand_write_ecc: write_page failed %d\n", ret);
                  goto out;
            }
            /* Next oob page */
            oob += mtd->oobsize;
            /* Update written bytes count */
            written += mtd->oobblock;
            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;
                  this->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_ecc: 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 &= this->pagemask;
                  startpage = page;
                  oob = 0;
                  this->oobdirty = 1;
                  oobbuf = nand_prepare_oobbuf (mtd, eccbuf, oobsel,
                              autoplace, numpages);
                  /* Check, if we cross a chip boundary */
                  if (!page) {
                        chipnr++;
                        this->select_chip(mtd, -1);
                        this->select_chip(mtd, chipnr);
                  }
            }
      }
      /* Verify the remaining pages */
cmp:
      this->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_ecc: 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 u_char * buf)
{
      int column, page, status, ret = -EIO, chipnr;
      struct nand_chip *this = mtd->priv;

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

      /* Shift to get page */
      page = (int) (to >> this->page_shift);
      chipnr = (int) (to >> this->chip_shift);

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

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

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

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

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

      /* 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. */
      this->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 == this->pagebuf)
            this->pagebuf = -1;

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

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

      /* See if device thinks it succeeded */
      if (status & 0x01) {
            DEBUG (MTD_DEBUG_LEVEL0, "nand_write_oob: " "Failed write, page 0x%08x\n", page);
            ret = -EIO;
            goto out;
      }
      /* Return happy */
      *retlen = len;

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

      if (this->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;
}

/* XXX U-BOOT XXX */
#if 0
/**
 * nand_writev - [MTD Interface] compabilty function for nand_writev_ecc
 * @mtd:    MTD device structure
 * @vecs:   the iovectors to write
 * @count:  number of vectors
 * @to:           offset to write to
 * @retlen: pointer to variable to store the number of written bytes
 *
 * NAND write with kvec. This just calls the ecc function
 */
static int nand_writev (struct mtd_info *mtd, const struct kvec *vecs, unsigned long count,
            loff_t to, size_t * retlen)
{
      return (nand_writev_ecc (mtd, vecs, count, to, retlen, NULL, NULL));
}

/**
 * nand_writev_ecc - [MTD Interface] write with iovec with ecc
 * @mtd:    MTD device structure
 * @vecs:   the iovectors to write
 * @count:  number of vectors
 * @to:           offset to write to
 * @retlen: pointer to variable to store the number of written bytes
 * @eccbuf: filesystem supplied oob data buffer
 * @oobsel: oob selection structure
 *
 * NAND write with iovec with ecc
 */
static int nand_writev_ecc (struct mtd_info *mtd, const struct kvec *vecs, unsigned long count,
            loff_t to, size_t * retlen, u_char *eccbuf, struct nand_oobinfo *oobsel)
{
      int i, page, len, total_len, ret = -EIO, written = 0, chipnr;
      int oob, numpages, autoplace = 0, startpage;
      struct nand_chip *this = mtd->priv;
      int   ppblock = (1 << (this->phys_erase_shift - this->page_shift));
      u_char *oobbuf, *bufstart;

      /* Preset written len for early exit */
      *retlen = 0;

      /* Calculate total length of data */
      total_len = 0;
      for (i = 0; i < count; i++)
            total_len += (int) vecs[i].iov_len;

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

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

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

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

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

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

      /* if oobsel is NULL, use chip defaults */
      if (oobsel == NULL)
            oobsel = &mtd->oobinfo;

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

      /* Setup start page */
      page = (int) (to >> this->page_shift);
      /* Invalidate the page cache, if we write to the cached page */
      if (page <= this->pagebuf && this->pagebuf < ((to + total_len) >> this->page_shift))
            this->pagebuf = -1;

      startpage = page & this->pagemask;

      /* Loop until all kvec' data has been written */
      len = 0;
      while (count) {
            /* If the given tuple is >= pagesize then
             * write it out from the iov
             */
            if ((vecs->iov_len - len) >= mtd->oobblock) {
                  /* Calc number of pages we can write
                   * out of this iov in one go */
                  numpages = (vecs->iov_len - len) >> this->page_shift;
                  /* Do not cross block boundaries */
                  numpages = min (ppblock - (startpage & (ppblock - 1)), numpages);
                  oobbuf = nand_prepare_oobbuf (mtd, NULL, oobsel, autoplace, numpages);
                  bufstart = (u_char *)vecs->iov_base;
                  bufstart += len;
                  this->data_poi = bufstart;
                  oob = 0;
                  for (i = 1; i <= numpages; i++) {
                        /* Write one page. If this is the last page to write
                         * then use the real pageprogram command, else select
                         * cached programming if supported by the chip.
                         */
                        ret = nand_write_page (mtd, this, page & this->pagemask,
                              &oobbuf[oob], oobsel, i != numpages);
                        if (ret)
                              goto out;
                        this->data_poi += mtd->oobblock;
                        len += mtd->oobblock;
                        oob += mtd->oobsize;
                        page++;
                  }
                  /* Check, if we have to switch to the next tuple */
                  if (len >= (int) vecs->iov_len) {
                        vecs++;
                        len = 0;
                        count--;
                  }
            } else {
                  /* We must use the internal buffer, read data out of each
                   * tuple until we have a full page to write
                   */
                  int cnt = 0;
                  while (cnt < mtd->oobblock) {
                        if (vecs->iov_base != NULL && vecs->iov_len)
                              this->data_buf[cnt++] = ((u_char *) vecs->iov_base)[len++];
                        /* Check, if we have to switch to the next tuple */
                        if (len >= (int) vecs->iov_len) {
                              vecs++;
                              len = 0;
                              count--;
                        }
                  }
                  this->pagebuf = page;
                  this->data_poi = this->data_buf;
                  bufstart = this->data_poi;
                  numpages = 1;
                  oobbuf = nand_prepare_oobbuf (mtd, NULL, oobsel, autoplace, numpages);
                  ret = nand_write_page (mtd, this, page & this->pagemask,
                        oobbuf, oobsel, 0);
                  if (ret)
                        goto out;
                  page++;
            }

            this->data_poi = bufstart;
            ret = nand_verify_pages (mtd, this, startpage, numpages, oobbuf, oobsel, chipnr, 0);
            if (ret)
                  goto out;

            written += mtd->oobblock * numpages;
            /* All done ? */
            if (!count)
                  break;

            startpage = page & this->pagemask;
            /* Check, if we cross a chip boundary */
            if (!startpage) {
                  chipnr++;
                  this->select_chip(mtd, -1);
                  this->select_chip(mtd, chipnr);
            }
      }
      ret = 0;
out:
      /* Deselect and wake up anyone waiting on the device */
      nand_release_device(mtd);

      *retlen = written;
      return ret;
}
#endif

/**
 * 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 *this = mtd->priv;
      /* Send commands to erase a block */
      this->cmdfunc (mtd, NAND_CMD_ERASE1, -1, page);
      this->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 *this = mtd->priv;
      /* Send commands to erase a block */
      this->cmdfunc (mtd, NAND_CMD_ERASE1, -1, page++);
      this->cmdfunc (mtd, NAND_CMD_ERASE1, -1, page++);
      this->cmdfunc (mtd, NAND_CMD_ERASE1, -1, page++);
      this->cmdfunc (mtd, NAND_CMD_ERASE1, -1, page);
      this->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);
}

/**
 * nand_erase_intern - [NAND Interface] 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 *this = mtd->priv;

      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 << this->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 << this->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 (this, mtd, FL_ERASING);

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

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

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

      /* Check the WP bit */
      /* 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;
      }

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

      instr->state = MTD_ERASING;

      while (len) {
#ifndef NAND_ALLOW_ERASE_ALL
            /* Check if we have a bad block, we do not erase bad blocks ! */
            if (nand_block_checkbad(mtd, ((loff_t) page) << this->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;
            }
#endif
            /* Invalidate the page cache, if we erase the block which contains
               the current cached page */
            if (page <= this->pagebuf && this->pagebuf < (page + pages_per_block))
                  this->pagebuf = -1;

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

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

            /* See if block erase succeeded */
            if (status & 0x01) {
                  DEBUG (MTD_DEBUG_LEVEL0, "nand_erase: " "Failed erase, page 0x%08x\n", page);
                  instr->state = MTD_ERASE_FAILED;
                  instr->fail_addr = (page << this->page_shift);
                  goto erase_exit;
            }

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

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

      /* 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 *this = mtd->priv;

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

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


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

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

/**
 * nand_block_markbad - [MTD Interface] Mark the 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 *this = 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 this->block_markbad(mtd, ofs);
}

/**
 * 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 not initialized 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
 *
 */
int nand_scan (struct mtd_info *mtd, int maxchips)
{
      int i, j, nand_maf_id, nand_dev_id, busw;
      struct nand_chip *this = mtd->priv;

      /* Get buswidth to select the correct functions*/
      busw = this->options & NAND_BUSWIDTH_16;

      /* check for proper chip_delay setup, set 20us if not */
      if (!this->chip_delay)
            this->chip_delay = 20;

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

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

      if (!this->select_chip)
            this->select_chip = nand_select_chip;
      if (!this->write_byte)
            this->write_byte = busw ? nand_write_byte16 : nand_write_byte;
      if (!this->read_byte)
            this->read_byte = busw ? nand_read_byte16 : nand_read_byte;
      if (!this->write_word)
            this->write_word = nand_write_word;
      if (!this->read_word)
            this->read_word = nand_read_word;
      if (!this->block_bad)
            this->block_bad = nand_block_bad;
      if (!this->block_markbad)
            this->block_markbad = nand_default_block_markbad;
      if (!this->write_buf)
            this->write_buf = busw ? nand_write_buf16 : nand_write_buf;
      if (!this->read_buf)
            this->read_buf = busw ? nand_read_buf16 : nand_read_buf;
      if (!this->verify_buf)
            this->verify_buf = busw ? nand_verify_buf16 : nand_verify_buf;
      if (!this->scan_bbt)
            this->scan_bbt = nand_default_bbt;

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

      /*
       * Reset the chip, required by some chips
       * (e.g. Micron MT29FxGxxxxx) after power-up
       */
      this->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);

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

      /* Read manufacturer and device IDs */
      nand_maf_id = this->read_byte(mtd);
      nand_dev_id = this->read_byte(mtd);

      /* Print and store flash device information */
      for (i = 0; nand_flash_ids[i].name != NULL; i++) {

            if (nand_dev_id != nand_flash_ids[i].id)
                  continue;

            if (!mtd->name) mtd->name = nand_flash_ids[i].name;
            this->chipsize = nand_flash_ids[i].chipsize << 20;

            /* New 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 = this->read_byte(mtd);
                  /* The 4th id byte is the important one */
                  extid = this->read_byte(mtd);
                  /* Calc pagesize */
                  mtd->oobblock = 1024 << (extid & 0x3);
                  extid >>= 2;
                  /* Calc oobsize */
                  mtd->oobsize = (8 << (extid & 0x03)) * (mtd->oobblock / 512);
                  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 this data hardcoded in the
                   * device id table */
                  mtd->erasesize = nand_flash_ids[i].erasesize;
                  mtd->oobblock = nand_flash_ids[i].pagesize;
                  mtd->oobsize = mtd->oobblock / 32;
                  busw = nand_flash_ids[i].options & NAND_BUSWIDTH_16;
            }

            /* Check, if buswidth is correct. Hardware drivers should set
             * this correct ! */
            if (busw != (this->options & NAND_BUSWIDTH_16)) {
                  printk (KERN_INFO "NAND device: Manufacturer ID:"
                        " 0x%02x, Chip ID: 0x%02x (%s %s)\n", nand_maf_id, nand_dev_id,
                        nand_manuf_ids[i].name , mtd->name);
                  printk (KERN_WARNING
                        "NAND bus width %d instead %d bit\n",
                              (this->options & NAND_BUSWIDTH_16) ? 16 : 8,
                              busw ? 16 : 8);
                  this->select_chip(mtd, -1);
                  return 1;
            }

            /* Calculate the address shift from the page size */
            this->page_shift = ffs(mtd->oobblock) - 1;
            this->bbt_erase_shift = this->phys_erase_shift = ffs(mtd->erasesize) - 1;
            this->chip_shift = ffs(this->chipsize) - 1;

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

            /* Get chip options, preserve non chip based options */
            this->options &= ~NAND_CHIPOPTIONS_MSK;
            this->options |= nand_flash_ids[i].options & NAND_CHIPOPTIONS_MSK;
            /* Set this as a default. Board drivers can override it, if neccecary */
            this->options |= NAND_NO_AUTOINCR;
            /* Check if this is a not a samsung device. Do not clear the options
             * for chips which are not having an extended id.
             */
            if (nand_maf_id != NAND_MFR_SAMSUNG && !nand_flash_ids[i].pagesize)
                  this->options &= ~NAND_SAMSUNG_LP_OPTIONS;

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

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

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

      if (!nand_flash_ids[i].name) {
            printk (KERN_WARNING "No NAND device found!!!\n");
            this->select_chip(mtd, -1);
            return 1;
      }

      for (i=1; i < maxchips; i++) {
            this->select_chip(mtd, i);

            /*
             * Reset the chip, required by some chips
             * (e.g. Micron MT29FxGxxxxx) after power-up
             */
            this->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);

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

            /* Read manufacturer and device IDs */
            if (nand_maf_id != this->read_byte(mtd) ||
                nand_dev_id != this->read_byte(mtd))
                  break;
      }
      if (i > 1)
            printk(KERN_INFO "%d NAND chips detected\n", i);

      /* Allocate buffers, if neccecary */
      if (!this->oob_buf) {
            size_t len;
            len = mtd->oobsize << (this->phys_erase_shift - this->page_shift);
            this->oob_buf = kmalloc (len, GFP_KERNEL);
            if (!this->oob_buf) {
                  printk (KERN_ERR "nand_scan(): Cannot allocate oob_buf\n");
                  return -ENOMEM;
            }
            this->options |= NAND_OOBBUF_ALLOC;
      }

      if (!this->data_buf) {
            size_t len;
            len = mtd->oobblock + mtd->oobsize;
            this->data_buf = kmalloc (len, GFP_KERNEL);
            if (!this->data_buf) {
                  if (this->options & NAND_OOBBUF_ALLOC)
                        kfree (this->oob_buf);
                  printk (KERN_ERR "nand_scan(): Cannot allocate data_buf\n");
                  return -ENOMEM;
            }
            this->options |= NAND_DATABUF_ALLOC;
      }

      /* Store the number of chips and calc total size for mtd */
      this->numchips = i;
      mtd->size = i * this->chipsize;
      /* Convert chipsize to number of pages per chip -1. */
      this->pagemask = (this->chipsize >> this->page_shift) - 1;
      /* Preset the internal oob buffer */
      memset(this->oob_buf, 0xff, mtd->oobsize << (this->phys_erase_shift - this->page_shift));

      /* If no default placement scheme is given, select an
       * appropriate one */
      if (!this->autooob) {
            /* Select the appropriate default oob placement scheme for
             * placement agnostic filesystems */
            switch (mtd->oobsize) {
            case 8:
                  this->autooob = &nand_oob_8;
                  break;
            case 16:
                  this->autooob = &nand_oob_16;
                  break;
            case 64:
                  this->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 */
      if (this->options & NAND_BUSWIDTH_16) {
            mtd->oobavail = mtd->oobsize - (this->autooob->eccbytes + 2);
            if (this->autooob->eccbytes & 0x01)
                  mtd->oobavail--;
      } else
            mtd->oobavail = mtd->oobsize - (this->autooob->eccbytes + 1);

      /*
       * check ECC mode, default to software
       * if 3byte/512byte hardware ECC is selected and we have 256 byte pagesize
       * fallback to software ECC
      */
      if (512 != this->eccsize)
            this->eccsize = 256;    /* set default eccsize */
      this->eccbytes = 3;

      switch (this->eccmode) {
      case NAND_ECC_HW12_2048:
            if (mtd->oobblock < 2048) {
                  printk(KERN_WARNING "2048 byte HW ECC not possible on %d byte page size, fallback to SW ECC\n",
                         mtd->oobblock);
                  this->eccmode = NAND_ECC_SOFT;
                  this->calculate_ecc = nand_calculate_ecc;
                  this->correct_data = nand_correct_data;
            } else
                  this->eccsize = 2048;
            break;

      case NAND_ECC_HW3_512:
      case NAND_ECC_HW6_512:
      case NAND_ECC_HW8_512:
            if (mtd->oobblock == 256) {
                  printk (KERN_WARNING "512 byte HW ECC not possible on 256 Byte pagesize, fallback to SW ECC \n");
                  this->eccmode = NAND_ECC_SOFT;
                  this->calculate_ecc = nand_calculate_ecc;
                  this->correct_data = nand_correct_data;
            } else
                  this->eccsize = 512; /* set eccsize to 512 */
            break;

      case NAND_ECC_HW3_256:
            break;

      case NAND_ECC_NONE:
            printk (KERN_WARNING "NAND_ECC_NONE selected by board driver. This is not recommended !!\n");
            this->eccmode = NAND_ECC_NONE;
            break;

      case NAND_ECC_SOFT:
            this->calculate_ecc = nand_calculate_ecc;
            this->correct_data = nand_correct_data;
            break;

      default:
            printk (KERN_WARNING "Invalid NAND_ECC_MODE %d\n", this->eccmode);
/*          BUG(); */
      }

      /* Check hardware ecc function availability and adjust number of ecc bytes per
       * calculation step
      */
      switch (this->eccmode) {
      case NAND_ECC_HW12_2048:
            this->eccbytes += 4;
      case NAND_ECC_HW8_512:
            this->eccbytes += 2;
      case NAND_ECC_HW6_512:
            this->eccbytes += 3;
      case NAND_ECC_HW3_512:
      case NAND_ECC_HW3_256:
            if (this->calculate_ecc && this->correct_data && this->enable_hwecc)
                  break;
            printk (KERN_WARNING "No ECC functions supplied, Hardware ECC not possible\n");
/*          BUG();      */
      }

      mtd->eccsize = this->eccsize;

      /* Set the number of read / write steps for one page to ensure ECC generation */
      switch (this->eccmode) {
      case NAND_ECC_HW12_2048:
            this->eccsteps = mtd->oobblock / 2048;
            break;
      case NAND_ECC_HW3_512:
      case NAND_ECC_HW6_512:
      case NAND_ECC_HW8_512:
            this->eccsteps = mtd->oobblock / 512;
            break;
      case NAND_ECC_HW3_256:
      case NAND_ECC_SOFT:
            this->eccsteps = mtd->oobblock / this->eccsize;
            break;

      case NAND_ECC_NONE:
            this->eccsteps = 1;
            break;
      }

/* XXX U-BOOT XXX */
#if 0
      /* Initialize state, waitqueue and spinlock */
      this->state = FL_READY;
      init_waitqueue_head (&this->wq);
      spin_lock_init (&this->chip_lock);
#endif

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

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

      /* Fill in remaining MTD driver data */
      mtd->type = MTD_NANDFLASH;
      mtd->flags = MTD_CAP_NANDFLASH | MTD_ECC;
      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_ecc = nand_read_ecc;
      mtd->write_ecc = nand_write_ecc;
      mtd->read_oob = nand_read_oob;
      mtd->write_oob = nand_write_oob;
/* XXX U-BOOT XXX */
#if 0
      mtd->readv = NULL;
      mtd->writev = nand_writev;
      mtd->writev_ecc = nand_writev_ecc;
#endif
      mtd->sync = nand_sync;
/* XXX U-BOOT XXX */
#if 0
      mtd->lock = NULL;
      mtd->unlock = NULL;
      mtd->suspend = NULL;
      mtd->resume = NULL;
#endif
      mtd->block_isbad = nand_block_isbad;
      mtd->block_markbad = nand_block_markbad;

      /* and make the autooob the default one */
      memcpy(&mtd->oobinfo, this->autooob, sizeof(mtd->oobinfo));
/* XXX U-BOOT XXX */
#if 0
      mtd->owner = THIS_MODULE;
#endif
      /* Build bad block table */
      return this->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 *this = mtd->priv;

#ifdef CONFIG_MTD_PARTITIONS
      /* Deregister partitions */
      del_mtd_partitions (mtd);
#endif
      /* Deregister the device */
/* XXX U-BOOT XXX */
#if 0
      del_mtd_device (mtd);
#endif
      /* Free bad block table memory, if allocated */
      if (this->bbt)
            kfree (this->bbt);
      /* Buffer allocated by nand_scan ? */
      if (this->options & NAND_OOBBUF_ALLOC)
            kfree (this->oob_buf);
      /* Buffer allocated by nand_scan ? */
      if (this->options & NAND_DATABUF_ALLOC)
            kfree (this->data_buf);
}

#endif

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