ret = 0;

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

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

#ifdef NAND_DEBUG
	printf("%d flash chips found. Total nand_chip size: %ld MB\n",
	       nand->numchips, nand->totlen >> 20);
#endif
}

/* we need to be fast here, 1 us per read translates to 1 second per meg */
static void NanD_ReadBuf(struct nand_chip *nand, u_char *data_buf, int cntr)
{
	unsigned long nandptr = nand->IO_ADDR;

	while (cntr >= 16) {
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		*data_buf++ = READ_NAND(nandptr);
		cntr -= 16;
	}

	while (cntr > 0) {
		*data_buf++ = READ_NAND(nandptr);
		cntr--;
	}
}

/*
 * NAND read with ECC
 */
static int nand_read_ecc(struct nand_chip *nand, size_t start, size_t len,
		 size_t * retlen, u_char *buf, u_char *ecc_code)
{
	int col, page;
	int ecc_status = 0;
#ifdef CONFIG_MTD_NAND_ECC
	int j;
	int ecc_failed = 0;
	u_char *data_poi;
	u_char ecc_calc[6];
#endif

	/* Do not allow reads past end of device */
	if ((start + len) > nand->totlen) {
//		printf ("%s: Attempt read beyond end of device %x %x %x\n", __FUNCTION__, (uint) start, (uint) len, (uint) nand->totlen);
		*retlen = 0;
		return -1;
	}

	/* First we calculate the starting page */
	/*page = shr(start, nand->page_shift);*/
	page = start >> nand->page_shift;

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

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

	/* Select the NAND device */
	NAND_ENABLE_CE(nand);  /* set pin low */

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


#ifdef CONFIG_MTD_NAND_ECC

		/* Do we have this page in cache ? */
		if (nand->cache_page == page)
			goto readdata;
		/* Send the read command */
		NanD_Command(nand, NAND_CMD_READ0);
		NanD_Address(nand, ADDR_COLUMN_PAGE, (page << nand->page_shift) + col);
		/* Read in a page + oob data */
		NanD_ReadBuf(nand, nand->data_buf, nand->oobblock + nand->oobsize);

		/* copy data into cache, for read out of cache and if ecc fails */
		if (nand->data_cache)
			memcpy (nand->data_cache, nand->data_buf, nand->oobblock + nand->oobsize);

		/* Pick the ECC bytes out of the oob data */
		for (j = 0; j < 6; j++)
			ecc_code[j] = nand->data_buf[(nand->oobblock + oob_config.ecc_pos[j])];

		/* Calculate the ECC and verify it */
		/* If block was not written with ECC, skip ECC */
		if (oob_config.eccvalid_pos != -1 &&
		    (nand->data_buf[nand->oobblock + oob_config.eccvalid_pos] & 0x0f) != 0x0f) {

			nand_calculate_ecc (&nand->data_buf[0], &ecc_calc[0]);
			switch (nand_correct_data (&nand->data_buf[0], &ecc_code[0], &ecc_calc[0])) {
			case -1:
//				printf ("%s: Failed ECC read, page 0x%08x\n", __FUNCTION__, page);
				ecc_failed++;
				break;
			case 1:
			case 2:	/* transfer ECC corrected data to cache */
				if (nand->data_cache)
					memcpy (nand->data_cache, nand->data_buf, 256);
				break;
			}
		}

		if (oob_config.eccvalid_pos != -1 &&
		    nand->oobblock == 512 && (nand->data_buf[nand->oobblock + oob_config.eccvalid_pos] & 0xf0) != 0xf0) {

			nand_calculate_ecc (&nand->data_buf[256], &ecc_calc[3]);
			switch (nand_correct_data (&nand->data_buf[256], &ecc_code[3], &ecc_calc[3])) {
			case -1:
//				printf ("%s: Failed ECC read, page 0x%08x\n", __FUNCTION__, page);
				ecc_failed++;
				break;
			case 1:
			case 2:	/* transfer ECC corrected data to cache */
				if (nand->data_cache)
					memcpy (&nand->data_cache[256], &nand->data_buf[256], 256);
				break;
			}
		}
readdata:
		/* Read the data from ECC data buffer into return buffer */
		data_poi = (nand->data_cache) ? nand->data_cache : nand->data_buf;
		data_poi += col;
		if ((*retlen + (nand->oobblock - col)) >= len) {
			memcpy (buf + *retlen, data_poi, len - *retlen);
			*retlen = len;
		} else {
			memcpy (buf + *retlen, data_poi,  nand->oobblock - col);
			*retlen += nand->oobblock - col;
		}
		/* Set cache page address, invalidate, if ecc_failed */
		nand->cache_page = (nand->data_cache && !ecc_failed) ? page : -1;

		ecc_status += ecc_failed;
		ecc_failed = 0;

#else
		/* Send the read command */
		NanD_Command(nand, NAND_CMD_READ0);
		NanD_Address(nand, ADDR_COLUMN_PAGE, (page << nand->page_shift) + col);
		/* Read the data directly into the return buffer */
		if ((*retlen + (nand->oobblock - col)) >= len) {
			NanD_ReadBuf(nand, buf + *retlen, len - *retlen);
			*retlen = len;
			/* We're done */
			continue;
		} else {
			NanD_ReadBuf(nand, buf + *retlen, nand->oobblock - col);
			*retlen += nand->oobblock - col;
			}
#endif
		/* For subsequent reads align to page boundary. */
		col = 0;
		/* Increment page address */
		page++;
	}

	/* De-select the NAND device */
	NAND_DISABLE_CE(nand);  /* set pin high */

	/*
	 * Return success, if no ECC failures, else -EIO
	 * fs driver will take care of that, because
	 * retlen == desired len and result == -EIO
	 */
	return ecc_status ? -1 : 0;
}

/*
 *	Nand_page_program function is used for write and writev !
 */
static int nand_write_page (struct nand_chip *nand,
			    int page, int col, int last, u_char * ecc_code)
{

	int i;
	unsigned long nandptr = nand->IO_ADDR;
#ifdef CONFIG_MTD_NAND_ECC
#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
	int ecc_bytes = (nand->oobblock == 512) ? 6 : 3;
#endif
#endif
	/* pad oob area */
	for (i = nand->oobblock; i < nand->oobblock + nand->oobsize; i++)
		nand->data_buf[i] = 0xff;

#ifdef CONFIG_MTD_NAND_ECC
	/* Zero out the ECC array */
	for (i = 0; i < 6; i++)
		ecc_code[i] = 0x00;

	/* Read back previous written data, if col > 0 */
	if (col) {
		NanD_Command(nand, NAND_CMD_READ0);
		NanD_Address(nand, ADDR_COLUMN_PAGE, (page << nand->page_shift) + col);
		for (i = 0; i < col; i++)
			nand->data_buf[i] = READ_NAND (nandptr);
	}

	/* Calculate and write the ECC if we have enough data */
	if ((col < nand->eccsize) && (last >= nand->eccsize)) {
		nand_calculate_ecc (&nand->data_buf[0], &(ecc_code[0]));
		for (i = 0; i < 3; i++)
			nand->data_buf[(nand->oobblock + oob_config.ecc_pos[i])] = ecc_code[i];
		if (oob_config.eccvalid_pos != -1)
			nand->data_buf[nand->oobblock + oob_config.eccvalid_pos] = 0xf0;
	}

	/* Calculate and write the second ECC if we have enough data */
	if ((nand->oobblock == 512) && (last == nand->oobblock)) {
		nand_calculate_ecc (&nand->data_buf[256], &(ecc_code[3]));
		for (i = 3; i < 6; i++)
			nand->data_buf[(nand->oobblock + oob_config.ecc_pos[i])] = ecc_code[i];
		if (oob_config.eccvalid_pos != -1)
			nand->data_buf[nand->oobblock + oob_config.eccvalid_pos] &= 0x0f;
	}
#endif
	/* Prepad for partial page programming !!! */
	for (i = 0; i < col; i++)
		nand->data_buf[i] = 0xff;

	/* Postpad for partial page programming !!! oob is already padded */
	for (i = last; i < nand->oobblock; i++)
		nand->data_buf[i] = 0xff;

	/* Send command to begin auto page programming */
	NanD_Command(nand, NAND_CMD_READ0);
	NanD_Command(nand, NAND_CMD_SEQIN);
	NanD_Address(nand, ADDR_COLUMN_PAGE, (page << nand->page_shift) + col);

	/* Write out complete page of data */
	for (i = 0; i < (nand->oobblock + nand->oobsize); i++)
		WRITE_NAND(nand->data_buf[i], nand->IO_ADDR);

	/* Send command to actually program the data */
	NanD_Command(nand, NAND_CMD_PAGEPROG);
	NanD_Command(nand, NAND_CMD_STATUS);
#ifdef NAND_NO_RB
	{ u_char ret_val;

	  do{
		ret_val = READ_NAND(nandptr);	/* wait till ready */
	  } while((ret_val & 0x40) != 0x40);
	}
#endif
	/* See if device thinks it succeeded */
	if (READ_NAND(nand->IO_ADDR) & 0x01) {
//		printf ("%s: Failed write, page 0x%08x, ", __FUNCTION__, page);
		return -1;
	}

#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
	/*
	 * 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.
	 */

	/* Send command to read back the page */
	if (col < nand->eccsize)
		NanD_Command(nand, NAND_CMD_READ0);
	else
		NanD_Command(nand, NAND_CMD_READ1);
	NanD_Address(nand, ADDR_COLUMN_PAGE, (page << nand->page_shift) + col);

	/* Loop through and verify the data */
	for (i = col; i < last; i++) {
		if (nand->data_buf[i] != readb (nand->IO_ADDR)) {
			printf ("%s: Failed write verify, page 0x%08x ", __FUNCTION__, page);
			return -1;
		}
	}

#ifdef CONFIG_MTD_NAND_ECC
	/*
	 * We also want to check that the ECC bytes wrote
	 * correctly for the same reasons stated above.
	 */
	NanD_Command(nand, NAND_CMD_READOOB);
	NanD_Address(nand, ADDR_COLUMN_PAGE, (page << nand->page_shift) + col);
	for (i = 0; i < nand->oobsize; i++)
		nand->data_buf[i] = readb (nand->IO_ADDR);
	for (i = 0; i < ecc_bytes; i++) {
		if ((nand->data_buf[(oob_config.ecc_pos[i])] != ecc_code[i]) && ecc_code[i]) {
			printf ("%s: Failed ECC write "
			       "verify, page 0x%08x, " "%6i bytes were succesful\n", __FUNCTION__, page, i);
			return -1;
		}
	}
#endif
#endif
	return 0;
}

static int nand_write_ecc (struct nand_chip* nand, size_t to, size_t len,
			   size_t * retlen, const u_char * buf, u_char * ecc_code)
{
	int i, page, col, cnt, ret = 0;

	/* Do not allow write past end of device */
	if ((to + len) > nand->totlen) {
		printf ("nand_write_ecc: Attempt to write past end of page\n");
		return -1;
	}

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

	/* Get the starting column */
	col = to & (nand->oobblock - 1);

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

	/* Select the NAND device */
   	NAND_ENABLE_CE(nand);  /* set pin low */

	/* Check the WP bit */
	NanD_Command(nand, NAND_CMD_STATUS);
	if (!(READ_NAND(nand->IO_ADDR) & 0x80)) {
		printf ("nand_write_ecc: Device is write protected!!!\n");
		ret = -1;
		goto out;
	}

	/* Loop until all data is written */
	while (*retlen < len) {
		/* Invalidate cache, if we write to this page */
		if (nand->cache_page == page)
			nand->cache_page = -1;

		/* Write data into buffer */
		if ((col + len) >= nand->oobblock)
			for (i = col, cnt = 0; i < nand->oobblock; i++, cnt++)
				nand->data_buf[i] = buf[(*retlen + cnt)];
		else
			for (i = col, cnt = 0; cnt < (len - *retlen); i++, cnt++)
				nand->data_buf[i] = buf[(*retlen + cnt)];
		/* We use the same function for write and writev !) */
		ret = nand_write_page (nand, page, col, i, ecc_code);
		if (ret)
			goto out;

		/* Next data start at page boundary */
		col = 0;

		/* Update written bytes count */
		*retlen += cnt;

		/* Increment page address */
		page++;
	}

	/* Return happy */
	*retlen = len;

out:
	/* De-select the NAND device */
	NAND_DISABLE_CE(nand);  /* set pin high */
	return ret;
}

/* read from the 16 bytes of oob data that correspond to a 512 byte
 * page or 2 256-byte pages.
 */
static int nand_read_oob(struct nand_chip* nand, size_t ofs, size_t len,
			 size_t * retlen, u_char * buf)
{
	int len256 = 0;
	struct Nand *mychip;
	int ret = 0;

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

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

	NAND_ENABLE_CE(nand);  /* set pin low */
	NanD_Command(nand, NAND_CMD_READOOB);
	NanD_Address(nand, ADDR_COLUMN_PAGE, ofs);

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

		NanD_Command(nand, NAND_CMD_READOOB);
		NanD_Address(nand, ADDR_COLUMN_PAGE, ofs & (~0x1ff));
	}

	NanD_ReadBuf(nand, &buf[len256], len - len256);

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

	ret = NanD_WaitReady(nand, 1);
	NAND_DISABLE_CE(nand);  /* set pin high */

	return ret;

}

/* write to the 16 bytes of oob data that correspond to a 512 byte
 * page or 2 256-byte pages.
 */
static int nand_write_oob(struct nand_chip* nand, size_t ofs, size_t len,
		  size_t * retlen, const u_char * buf)
{
	int len256 = 0;
	int i;