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

#else

#include <common.h>

#if (CONFIG_COMMANDS & CFG_CMD_NAND)

#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

#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
#define nand_release_device(mtd)	do {} while(0)
#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)
{
	/* TODO */
	return 0;
}
#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;
	int  	*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++) {