nand_base.c

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				/* Walk through the autoplace chunks */
				for (i = 0; oobsel->oobfree[i][1]; i++) {
					int from = oobsel->oobfree[i][0];
					int num = oobsel->oobfree[i][1];
					memcpy(&oob_buf[oob], &oob_data[from], num);
					oob += num;
				}
				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
			nand_wait_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 */
	if (flags & NAND_GET_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 * oob_buf)
{

	int i, j, col, realpage, page, end, ecc, chipnr, sndcmd = 1, reallen = 0;
	int read = 0;
	struct nand_chip *this = mtd->priv;
	u_char *oob_data = oob_buf;
        int 	eccsteps;
	int	blockcheck = (1 << (this->phys_erase_shift - this->page_shift)) - 1;


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

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

	/* Loop until all data read */
	while (read < len) {
		if (this->eccmode == NAND_ECC_SOFT || this->eccmode == NAND_ECC_NONE) {
			int thislen = mtd->oobsize - col;
			if (sndcmd) {
				this->cmdfunc (mtd, NAND_CMD_READOOB, col, page);
				col = 0;
				sndcmd = 0;
			}
			thislen = min_t(int, thislen, len);
			this->read_buf(mtd, &oob_buf[read], thislen);
			read += thislen;
		} else {
			/* Check, if we must send the read command */
			if (sndcmd) {
				this->cmdfunc (mtd, NAND_CMD_READ0, 0x00, page);
				sndcmd = 0;
			}

			eccsteps = this->eccsteps;
			for (j = 0; this->layout[j].length; j++) {
				i = 0;
				switch (this->layout[j].type) {
				case ITEM_TYPE_DATA:
					DEBUG (MTD_DEBUG_LEVEL3, "%s: dummy data read\n", __FUNCTION__);
					reallen += this->layout[j].length;
					if (this->options & NAND_BUSWIDTH_16)
						this->cmdfunc (mtd, NAND_CMD_READ0, reallen & ~1, page);
					else
						this->cmdfunc (mtd, NAND_CMD_READ0, reallen, page);
					break;

				case ITEM_TYPE_ECC:
				case ITEM_TYPE_OOB:
					DEBUG (MTD_DEBUG_LEVEL3, "%s: %s bytes read\n", __FUNCTION__, this->layout[j].type == ITEM_TYPE_ECC ? "ecc" : "oob");
					i = min_t(int, col, this->layout[j].length);
					if (i) {
						reallen += i;
						if (this->options & NAND_BUSWIDTH_16)
							this->cmdfunc (mtd, NAND_CMD_READ0, reallen & ~1, page);
						else
							this->cmdfunc (mtd, NAND_CMD_READ0, reallen, page);
					}
					col -= i;

					if (this->layout[j].type == ITEM_TYPE_ECC)
						this->enable_hwecc(mtd, NAND_ECC_READSYN);
					else
						this->enable_hwecc(mtd, NAND_ECC_READOOB);
					i = min_t(int, len - read, this->layout[j].length - i);
					if (i) {
						if (this->options & NAND_BUSWIDTH_16) {
							if (reallen & 1) {
								oob_data[0] = cpu_to_le16(this->read_word(mtd)) >> 8;
								oob_data++; i--; reallen++;
							}
							if (i & 1)
								this->read_buf(mtd, oob_data, i - 1);
							else
								this->read_buf(mtd, oob_data, i);
 						}
						else
							this->read_buf(mtd, oob_data, i);
						reallen += i;
					}
					if (oob_buf + len == oob_data + i) {
						read += i;
						goto out;
	 				}
					break;
 				}
				read += i;
				oob_data += i;
			}
		}
out:

		/* 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
			nand_wait_ready(mtd);

		if (read == len)
			break;

		/* For subsequent reads align to page boundary. */
		reallen = 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);

	*retlen = read;
	/*
	 * Return success
	 */
	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
			nand_wait_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);