nand_base.c

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

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

	return 0;
}

/**
 * nand_transfer_oob - [Internal] Transfer oob to client buffer
 * @chip:	nand chip structure
 * @oob:	oob destination address
 * @ops:	oob ops structure
 * @len:	size of oob to transfer
 */
static uint8_t *nand_transfer_oob(struct nand_chip *chip, uint8_t *oob,
				  struct mtd_oob_ops *ops, size_t len)
{
	switch(ops->mode) {

	case MTD_OOB_PLACE:
	case MTD_OOB_RAW:
		memcpy(oob, chip->oob_poi + ops->ooboffs, len);
		return oob + len;

	case MTD_OOB_AUTO: {
		struct nand_oobfree *free = chip->ecc.layout->oobfree;
		uint32_t boffs = 0, roffs = ops->ooboffs;
		size_t bytes = 0;

		for(; free->length && len; free++, len -= bytes) {
			/* Read request not from offset 0 ? */
			if (unlikely(roffs)) {
				if (roffs >= free->length) {
					roffs -= free->length;
					continue;
				}
				boffs = free->offset + roffs;
				bytes = min_t(size_t, len,
					      (free->length - roffs));
				roffs = 0;
			} else {
				bytes = min_t(size_t, len, free->length);
				boffs = free->offset;
			}
			memcpy(oob, chip->oob_poi + boffs, bytes);
			oob += bytes;
		}
		return oob;
	}
	default:
		BUG();
	}
	return NULL;
}

/**
 * nand_do_read_ops - [Internal] Read data with ECC
 *
 * @mtd:	MTD device structure
 * @from:	offset to read from
 * @ops:	oob ops structure
 *
 * Internal function. Called with chip held.
 */
static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
			    struct mtd_oob_ops *ops)
{
	int chipnr, page, realpage, col, bytes, aligned;
	struct nand_chip *chip = mtd->priv;
	struct mtd_ecc_stats stats;
	int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
	int sndcmd = 1;
	int ret = 0;
	uint32_t readlen = ops->len;
	uint32_t oobreadlen = ops->ooblen;
	uint8_t *bufpoi, *oob, *buf;

	stats = mtd->ecc_stats;

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

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

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

	buf = ops->datbuf;
	oob = ops->oobbuf;

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

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

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

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

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

			buf += bytes;

			if (unlikely(oob)) {
				/* Raw mode does data:oob:data:oob */
				if (ops->mode != MTD_OOB_RAW) {
					int toread = min(oobreadlen,
						chip->ecc.layout->oobavail);
					if (toread) {
						oob = nand_transfer_oob(chip,
							oob, ops, toread);
						oobreadlen -= toread;
					}
				} else
					buf = nand_transfer_oob(chip,
						buf, ops, mtd->oobsize);
			}

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

		readlen -= bytes;

		if (!readlen)
			break;

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

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

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

	ops->retlen = ops->len - (size_t) readlen;
	if (oob)
		ops->oobretlen = ops->ooblen - oobreadlen;

	if (ret)
		return ret;

	if (mtd->ecc_stats.failed - stats.failed)
		return -EBADMSG;

	return  mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
}

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

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

	nand_get_device(chip, mtd, FL_READING);

	chip->ops.len = len;
	chip->ops.datbuf = buf;
	chip->ops.oobbuf = NULL;

	ret = nand_do_read_ops(mtd, from, &chip->ops);

	*retlen = chip->ops.retlen;

	nand_release_device(mtd);

	return ret;
}

/**
 * nand_read_oob_std - [REPLACABLE] the most common OOB data read function
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @page:	page number to read
 * @sndcmd:	flag whether to issue read command or not
 */
static int nand_read_oob_std(struct mtd_info *mtd, struct nand_chip *chip,
			     int page, int sndcmd)
{
	if (sndcmd) {
		chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
		sndcmd = 0;
	}
	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
	return sndcmd;
}

/**
 * nand_read_oob_syndrome - [REPLACABLE] OOB data read function for HW ECC
 *			    with syndromes
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @page:	page number to read
 * @sndcmd:	flag whether to issue read command or not
 */
static int nand_read_oob_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
				  int page, int sndcmd)
{
	uint8_t *buf = chip->oob_poi;
	int length = mtd->oobsize;
	int chunk = chip->ecc.bytes + chip->ecc.prepad + chip->ecc.postpad;
	int eccsize = chip->ecc.size;
	uint8_t *bufpoi = buf;
	int i, toread, sndrnd = 0, pos;

	chip->cmdfunc(mtd, NAND_CMD_READ0, chip->ecc.size, page);
	for (i = 0; i < chip->ecc.steps; i++) {
		if (sndrnd) {
			pos = eccsize + i * (eccsize + chunk);
			if (mtd->writesize > 512)
				chip->cmdfunc(mtd, NAND_CMD_RNDOUT, pos, -1);
			else
				chip->cmdfunc(mtd, NAND_CMD_READ0, pos, page);
		} else
			sndrnd = 1;
		toread = min_t(int, length, chunk);
		chip->read_buf(mtd, bufpoi, toread);
		bufpoi += toread;
		length -= toread;
	}
	if (length > 0)
		chip->read_buf(mtd, bufpoi, length);

	return 1;
}

/**
 * nand_write_oob_std - [REPLACABLE] the most common OOB data write function
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @page:	page number to write
 */
static int nand_write_oob_std(struct mtd_info *mtd, struct nand_chip *chip,
			      int page)
{
	int status = 0;
	const uint8_t *buf = chip->oob_poi;
	int length = mtd->oobsize;

	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, page);
	chip->write_buf(mtd, buf, length);
	/* Send command to program the OOB data */
	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);

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

	return status & NAND_STATUS_FAIL ? -EIO : 0;
}

/**
 * nand_write_oob_syndrome - [REPLACABLE] OOB data write function for HW ECC
 *			     with syndrome - only for large page flash !
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @page:	page number to write
 */
static int nand_write_oob_syndrome(struct mtd_info *mtd,
				   struct nand_chip *chip, int page)
{
	int chunk = chip->ecc.bytes + chip->ecc.prepad + chip->ecc.postpad;
	int eccsize = chip->ecc.size, length = mtd->oobsize;
	int i, len, pos, status = 0, sndcmd = 0, steps = chip->ecc.steps;
	const uint8_t *bufpoi = chip->oob_poi;

	/*
	 * data-ecc-data-ecc ... ecc-oob
	 * or
	 * data-pad-ecc-pad-data-pad .... ecc-pad-oob
	 */
	if (!chip->ecc.prepad && !chip->ecc.postpad) {
		pos = steps * (eccsize + chunk);
		steps = 0;
	} else
		pos = eccsize;

	chip->cmdfunc(mtd, NAND_CMD_SEQIN, pos, page);
	for (i = 0; i < steps; i++) {
		if (sndcmd) {
			if (mtd->writesize <= 512) {
				uint32_t fill = 0xFFFFFFFF;

				len = eccsize;
				while (len > 0) {
					int num = min_t(int, len, 4);
					chip->write_buf(mtd, (uint8_t *)&fill,
							num);
					len -= num;
				}
			} else {
				pos = eccsize + i * (eccsize + chunk);
				chip->cmdfunc(mtd, NAND_CMD_RNDIN, pos, -1);
			}
		} else
			sndcmd = 1;
		len = min_t(int, length, chunk);
		chip->write_buf(mtd, bufpoi, len);
		bufpoi += len;
		length -= len;
	}
	if (length > 0)
		chip->write_buf(mtd, bufpoi, length);

	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
	status = chip->waitfunc(mtd, chip);

	return status & NAND_STATUS_FAIL ? -EIO : 0;
}

/**
 * nand_do_read_oob - [Intern] NAND read out-of-band
 * @mtd:	MTD device structure
 * @from:	offset to read from
 * @ops:	oob operations description structure
 *
 * NAND read out-of-band data from the spare area
 */
static int nand_do_read_oob(struct mtd_info *mtd, loff_t from,
			    struct mtd_oob_ops *ops)
{
	int page, realpage, chipnr, sndcmd = 1;
	struct nand_chip *chip = mtd->priv;
	int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
	int readlen = ops->ooblen;
	int len;
	uint8_t *buf = ops->oobbuf;

	MTDDEBUG (MTD_DEBUG_LEVEL3, "nand_read_oob: from = 0x%08Lx, len = %i\n",
	          (unsigned long long)from, readlen);

	if (ops->mode == MTD_OOB_AUTO)
		len = chip->ecc.layout->oobavail;
	else
		len = mtd->oobsize;

	if (unlikely(ops->ooboffs >= len)) {
		MTDDEBUG (MTD_DEBUG_LEVEL0, "nand_read_oob: "
		          "Attempt to start read outside oob\n");
		return -EINVAL;
	}

	/* Do not allow reads past end of device */
	if (unlikely(from >= mtd->size ||
		     ops->ooboffs + readlen > ((mtd->size >> chip->page_shift) -
					(from >> chip->page_shift)) * len)) {
		MTDDEBUG (MTD_DEBUG_LEVEL0, "nand_read_oob: "
		          "Attempt read beyond end of device\n");
		return -EINVAL;
	}

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

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

	while(1) {
		sndcmd = chip->ecc.read_oob(mtd, chip, page, sndcmd);

		len = min(len, readlen);
		buf = nand_transfer_oob(chip, buf, ops, len);

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

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

		/* Increment page address */
		realpage++;

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

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

	ops->oobretlen = ops->ooblen;
	return 0;
}

/**
 * nand_read_oob - [MTD Interface] NAND read data and/or out-of-band
 * @mtd:	MTD device structure
 * @from:	offset to read from
 * @ops:	oob operation description structure
 *
 * NAND read data and/or out-of-band data
 */
static int nand_read_oob(struct mtd_info *mtd, loff_t from,
			 struct mtd_oob_ops *ops)
{
	struct nand_chip *chip = mtd->priv;
	int ret = -ENOTSUPP;

	ops->retlen = 0;

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

	nand_get_device(chip, mtd, FL_READING);

	switch(ops->mode) {
	case MTD_OOB_PLACE:
	case MTD_OOB_AUTO:
	case MTD_OOB_RAW:
		break;

	default:
		goto out;
	}

	if (!ops->datbuf)
		ret = nand_do_read_oob(mtd, from, ops);
	else
		ret = nand_do_read_ops(mtd, from, ops);

 out:
	nand_release_device(mtd);
	return ret;
}


/**
 * nand_write_page_raw - [Intern] raw page write function
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @buf:	data buffer
 */
static void nand_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
				const uint8_t *buf)
{
	chip->write_buf(mtd, buf, mtd->writesize);
	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
}

/**
 * nand_write_page_swecc - [REPLACABLE] software ecc based page write function
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @buf:	data buffer
 */
static void nand_write_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
				  const uint8_t *buf)
{
	int i, eccsize = chip->ecc.size;
	int eccbytes = chip->ecc.bytes;
	int eccsteps = chip->ecc.steps;
	uint8_t *ecc_calc = chip->buffers->ecccalc;
	const uint8_t *p = buf;
	uint32_t *eccpos = chip->ecc.layout->eccpos;

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

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

	chip->ecc.write_page_raw(mtd, chip, buf);
}

/**
 * nand_write_page_hwecc - [REPLACABLE] hardware ecc based page write function
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @buf:	data buffer
 */
static void nand_write_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
				  const uint8_t *buf)
{
	int i, eccsize = chip->ecc.size;
	int eccbytes = chip->ecc.bytes;
	int eccsteps = chip->ecc.steps;
	uint8_t *ecc_calc = chip->buffers->ecccalc;
	const uint8_t *p = buf;
	uint32_t *eccpos = chip->ecc.layout->eccpos;

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

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

	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
}

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

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

		chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
		chip->write_buf(mtd, p, eccsize);

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

		chip->ecc.calculate(mtd, p, oob);
		chip->write_buf(mtd, oob, eccbytes);
		oob += eccbytes;

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

	/* Calculate remaining oob bytes */
	i = mtd->oobsize - (oob - chip->oob_poi);
	if (i)
		chip->write_buf(mtd, oob, i);
}

/**
 * nand_write_page - [REPLACEABLE] write one page
 * @mtd:	MTD device structure
 * @chip:	NAND chip descriptor
 * @buf:	the data to write
 * @page:	page number to write
 * @cached:	cached programming
 * @raw:	use _raw version of write_page
 */
static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
			   const uint8_t *buf, int page, int cached, int raw)
{
	int status;

	chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);

	if (unlikely(raw))
		chip->ecc.write_page_raw(mtd, chip, buf);
	else
		chip->ecc.write_page(mtd, chip, buf);

	/*
	 * Cached progamming disabled for now, Not sure if its worth the
	 * trouble. The speed gain is not very impressive. (2.3->2.6Mib/s)
	 */
	cached = 0;

	if (!cached || !(chip->options & NAND_CACHEPRG)) {

		chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
		status = chip->waitfunc(mtd, chip);
		/*
		 * See if operation failed and additional status checks are
		 * available
		 */
		if ((status & NAND_STATUS_FAIL) && (chip->errstat))
			status = chip->errstat(mtd, chip, FL_WRITING, status,
					       page);

		if (status & NAND_STATUS_FAIL)
			return -EIO;
	} else {
		chip->cmdfunc(mtd, NAND_CMD_CACHEDPROG, -1, -1);
		status = chip->waitfunc(mtd, chip);
	}

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

	if (chip->verify_buf(mtd, buf, mtd->writesize))
		return -EIO;
#endif
	return 0;
}

/**
 * nand_fill_oob - [Internal] Transfer client buffer to oob
 * @chip:	nand chip structure
 * @oob:	oob data buffer
 * @ops:	oob ops structure
 */
static uint8_t *nand_fill_oob(struct nand_chip *chip, uint8_t *oob,
				  struct mtd_oob_ops *ops)
{
	size_t len = ops->ooblen;

	switch(ops->mode) {

	case MTD_OOB_PLACE:
	case MTD_OOB_RAW:
		memcpy(chip->oob_poi + ops->ooboffs, oob, len);
		return oob + len;

	case MTD_OOB_AUTO: {
		struct nand_oobfree *free = chip->ecc.layout->oobfree;
		uint32_t boffs = 0, woffs = ops->ooboffs;
		size_t bytes = 0;

		for(; free->length && len; free++, len -= bytes) {
			/* Write request not from offset 0 ? */
			if (unlikely(woffs)) {
				if (woffs >= free->length) {
					woffs -= free->length;
					continue;
				}
				boffs = free->offset + woffs;
				bytes = min_t(size_t, len,
					      (free->length - woffs));
				woffs = 0;
			} else {
				bytes = min_t(size_t, len, free->length);
				boffs = free->offset;
			}
			memcpy(chip->oob_poi + boffs, oob, bytes);
			oob += bytes;
		}
		return oob;
	}
	default:
		BUG();
	}
	return NULL;
}

#define NOTALIGNED(x)	(x & (chip->subpagesize - 1)) != 0

/**
 * nand_do_write_ops - [Internal] NAND write with ECC
 * @mtd:	MTD device structure
 * @to:		offset to write to
 * @ops:	oob operations description structure
 *
 * NAND write with ECC
 */
static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
			     struct mtd_oob_ops *ops)
{
	int chipnr, realpage, page, blockmask, column;
	struct nand_chip *chip = mtd->priv;
	uint32_t writelen = ops->len;
	uint8_t *oob = ops->oobbuf;
	uint8_t *buf = ops->datbuf;
	int ret, subpage;

	ops->retlen = 0;
	if (!writelen)
		return 0;

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

	column = to & (mtd->writesize - 1);
	subpage = column || (writelen & (mtd->writesize - 1));

	if (subpage && oob)
		return -EINVAL;

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

	/* Check, if it is write protected */
	if (nand_check_wp(mtd)) {
		printk (KERN_NOTICE "nand_do_write_ops: Device is write protected\n");
		return -EIO;
	}

	realpage = (int)(to >> chip->page_shift);
	page = realpage & chip->pagemask;
	blockmask = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;

	/* Invalidate the page cache, when we write to the cached page */
	if (to <= (chip->pagebuf << chip->page_shift) &&
	    (chip->pagebuf << chip->page_shift) < (to + ops->len))
		chip->pagebuf = -1;

	/* If we're not given explicit OOB data, let it be 0xFF */
	if (likely(!oob))
		memset(chip->oob_poi, 0xff, mtd->oobsize);

	while(1) {
		int bytes = mtd->writesize;
		int cached = writelen > bytes && page != blockmask;
		uint8_t *wbuf = buf;

		/* Partial page write ? */
		if (unlikely(column || writelen < (mtd->writesize - 1))) {
			cached = 0;
			bytes = min_t(int, bytes - column, (int) writelen);
			chip->pagebuf = -1;
			memset(chip->buffers->databuf, 0xff, mtd->writesize);
			memcpy(&chip->buffers->databuf[column], buf, bytes);
			wbuf = chip->buffers->databuf;
		}

		if (unlikely(oob))
			oob = nand_fill_oob(chip, oob, ops);

		ret = chip->write_page(mtd, chip, wbuf, page, cached,
				       (ops->mode == MTD_OOB_RAW));
		if (ret)
			break;

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

		column = 0;
		buf += bytes;
		realpage++;

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

	ops->retlen = ops->len - writelen;
	if (unlikely(oob))
		ops->oobretlen = ops->ooblen;
	return ret;
}

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

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

	nand_get_device(chip, mtd, FL_WRITING);

	chip->ops.len = len;
	chip->ops.datbuf = (uint8_t *)buf;
	chip->ops.oobbuf = NULL;

	ret = nand_do_write_ops(mtd, to, &chip->ops);

	*retlen = chip->ops.retlen;

	nand_release_device(mtd);

	return ret;
}

/**
 * nand_do_write_oob - [MTD Interface] NAND write out-of-band
 * @mtd:	MTD device structure
 * @to:		offset to write to
 * @ops:	oob operation description structure
 *
 * NAND write out-of-band
 */
static int nand_do_write_oob(struct mtd_info *mtd, loff_t to,
			     struct mtd_oob_ops *ops)
{
	int chipnr, page, status, len;
	struct nand_chip *chip = mtd->priv;

	MTDDEBUG (MTD_DEBUG_LEVEL3, "nand_write_oob: to = 0x%08x, len = %i\n",
	          (unsigned int)to, (int)ops->ooblen);

	if (ops->mode == MTD_OOB_AUTO)
		len = chip->ecc.layout->oobavail;
	else
		len = mtd->oobsize;

	/* Do not allow write past end of page */
	if ((ops->ooboffs + ops->ooblen) > len) {
		MTDDEBUG (MTD_DEBUG_LEVEL0, "nand_write_oob: "
		          "Attempt to write past end of page\n");
		return -EINVAL;
	}

	if (unlikely(ops->ooboffs >= len)) {
		MTDDEBUG (MTD_DEBUG_LEVEL0, "nand_read_oob: "
		          "Attempt to start write outside oob\n");
		return -EINVAL;
	}

	/* Do not allow reads past end of device */
	if (unlikely(to >= mtd->size ||
		     ops->ooboffs + ops->ooblen >
			((mtd->size >> chip->page_shift) -
			 (to >> chip->page_shift)) * len)) {
		MTDDEBUG (MTD_DEBUG_LEVEL0, "nand_read_oob: "
		          "Attempt write beyond end of device\n");
		return -EINVAL;
	}

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

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

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

	/* Check, if it is write protected */
	if (nand_check_wp(mtd))
		return -EROFS;

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

	memset(chip->oob_poi, 0xff, mtd->oobsize);
	nand_fill_oob(chip, ops->oobbuf, ops);
	status = chip->ecc.write_oob(mtd, chip, page & chip->pagemask);
	memset(chip->oob_poi, 0xff, mtd->oobsize);

	if (status)
		return status;

	ops->oobretlen = ops->ooblen;

	return 0;
}

/**
 * nand_write_oob - [MTD Interface] NAND write data and/or out-of-band
 * @mtd:	MTD device structure
 * @to:		offset to write to
 * @ops:	oob operation description structure
 */
static int nand_write_oob(struct mtd_info *mtd, loff_t to,
			  struct mtd_oob_ops *ops)
{
	struct nand_chip *chip = mtd->priv;
	int ret = -ENOTSUPP;

	ops->retlen = 0;

	/* Do not allow writes past end of device */
	if (ops->datbuf && (to + ops->len) > mtd->size) {
		MTDDEBUG (MTD_DEBUG_LEVEL0, "nand_read_oob: "
		          "Attempt read beyond end of device\n");
		return -EINVAL;
	}

	nand_get_device(chip, mtd, FL_WRITING);

	switch(ops->mode) {
	case MTD_OOB_PLACE:
	case MTD_OOB_AUTO:
	case MTD_OOB_RAW:
		break;

	default:
		goto out;
	}

	if (!ops->datbuf)
		ret = nand_do_write_oob(mtd, to, ops);
	else
		ret = nand_do_write_ops(mtd, to, ops);

 out:
	nand_release_device(mtd);
	return ret;
}

/**
 * single_erease_cmd - [GENERIC] NAND standard block erase command function
 * @mtd:	MTD device structure
 * @page:	the page address of the block which will be erased
 *
 * Standard erase command for NAND chips