nand.c

linux下的MTD设备驱动源代码,配合jffs2 yaffss2文件系统.

		return -EINVAL;
	}

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

	/* 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) & (mtd->oobsize - 1);
		if (!thislen)
			thislen = mtd->oobsize;
		thislen = min_t(int, thislen, len);
		this->read_buf(mtd, &buf[i], thislen);
		i += thislen;
		col += thislen;
		/* Read more ? */
		if (i < len) {
			page++;
			/* 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));	

			/* 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_chip(mtd);

	/* Return happy */
	*retlen = len;
	return 0;
}

/* Prepare the out of band buffer 
 *
 * 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.
 *
 * @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
*/
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 * (mtd->erasesize / mtd->oobblock));
		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

/*
 * This function simply calls nand_write_ecc with oob buffer and oobsel = NULL
 *
 * @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
*/
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 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
 */
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 = mtd->erasesize >> 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_chip (this, mtd, FL_WRITING, NULL);

	/* Calculate chipnr */
	chipnr = (int)((unsigned long) to / this->chipsize);
	/* 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;
	}	

	/* 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;
			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_chip(mtd);

	return ret;
}


/*
 * 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
 */
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)((unsigned long)to / this->chipsize);

	/* 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_chip (this, mtd, FL_WRITING, NULL);

	/* 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_chip(mtd);

	return ret;
}


/*
 * NAND write with iovec. This just calls the ecc function
 *
 * @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
 */
static int nand_writev (struct mtd_info *mtd, const struct iovec *vecs, unsigned long count, 
		loff_t to, size_t * retlen)
{
	return (nand_writev_ecc (mtd, vecs, count, to, retlen, NULL, 0));	
}

/*
 * NAND 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
 */
static int nand_writev_ecc (struct mtd_info *mtd, const struct iovec *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 = mtd->erasesize >> 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_chip (this, mtd, FL_WRITING, NULL);

	/* Get the current chip-nr */
	chipnr = (int)((unsigned long) to / this->chipsize);
	/* 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;
	}	

	/* 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 iovecs' 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)