nand_base.c

老版本的mtd-snap

		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 operation failed and additional status checks are available */
		if ((status & NAND_STATUS_FAIL) && (this->errstat)) {
			status = this->errstat(mtd, this, FL_WRITING, status, page);
		}

		/* See if device thinks it succeeded */
		if (status & NAND_STATUS_FAIL) {
			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++) {
					int idx = oobsel->eccpos[i];
					if (oobdata[idx] != oob_buf[oobofs + idx] ) {
						DEBUG (MTD_DEBUG_LEVEL0,
					       	"%s: Failed ECC write "
						"verify, page 0x%08x, " "%6i bytes were succesful\n", __FUNCTION__, page, i);
						goto out;
					}
				}
			}	
		}
		oobofs += mtd->oobsize - hweccbytes * eccsteps;
		page++;
		numpages--;

		/* 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.
		 * Do this also before returning, so the chip is
		 * ready for the next command.
		*/
		if (!this->dev_ready) 
			udelay (this->chip_delay);
		else
			nand_wait_ready(mtd);

		/* All done, return happy */
		if (!numpages)
			return 0;
		
			
		/* Check, if the chip supports auto page increment */ 
		if (!NAND_CANAUTOINCR(this))
			this->cmdfunc (mtd, NAND_CMD_READ0, 0x00, page);
	}
	/* 
	 * Terminate the read command. We come here in case of an error
	 * So we must issue a reset command.
	 */
out:	 
	this->cmdfunc (mtd, NAND_CMD_RESET, -1, -1);
	return res;
}
#endif

/**
 * 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
 *
 * This function simply calls nand_do_read_ecc with oob buffer and oobsel = NULL
 * and flags = 0xff
 */
static int nand_read (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf)
{
	return nand_do_read_ecc (mtd, from, len, retlen, buf, NULL, &mtd->oobinfo, 0xff);
}


/**
 * nand_read_ecc - [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
 * @oob_buf:	filesystem supplied oob data buffer
 * @oobsel:	oob selection structure
 *
 * This function simply calls nand_do_read_ecc with flags = 0xff
 */
static int nand_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
			  size_t * retlen, u_char * buf, u_char * oob_buf, struct nand_oobinfo *oobsel)
{
	/* use userspace supplied oobinfo, if zero */
	if (oobsel == NULL)
		oobsel = &mtd->oobinfo;
	return nand_do_read_ecc(mtd, from, len, retlen, buf, oob_buf, oobsel, 0xff);
}


/**
 * nand_do_read_ecc - [MTD Interface] Read data with 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
 * @oob_buf:	filesystem supplied oob data buffer (can be NULL)
 * @oobsel:	oob selection structure
 * @flags:	flag to indicate if nand_get_device/nand_release_device should be preformed
 *		and how many corrected error bits are acceptable:
 *		  bits 0..7 - number of tolerable errors
 *		  bit  8    - 0 == do not get/release chip, 1 == get/release chip
 *
 * NAND read with ECC
 */
int nand_do_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
			     size_t * retlen, u_char * buf, u_char * oob_buf, 
			     struct nand_oobinfo *oobsel, int flags)
{

	int i, j, col, realpage, page, end, ecc, chipnr, sndcmd = 1;
	int read = 0, oob = 0, ecc_status = 0, ecc_failed = 0;
	struct nand_chip *this = mtd->priv;
	u_char *data_poi, *oob_data = oob_buf;
	u_char ecc_calc[32];
	u_char ecc_code[32];
        int eccmode, eccsteps;
	int	*oob_config, datidx;
	int	blockcheck = (1 << (this->phys_erase_shift - this->page_shift)) - 1;
	int	eccbytes;
	int	compareecc = 1;
	int	oobreadlen;


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

	/* Do not allow reads past end of device */
	if ((from + len) > mtd->size) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_read_ecc: Attempt read beyond end of device\n");
		*retlen = 0;
		return -EINVAL;
	}

	/* Grab the lock and see if the device is available */
	if (flags & NAND_GET_DEVICE)
		nand_get_device (this, mtd, FL_READING);

	/* Autoplace of oob data ? Use the default placement scheme */
	if (oobsel->useecc == MTD_NANDECC_AUTOPLACE)
		oobsel = this->autooob;
		
	eccmode = oobsel->useecc ? this->eccmode : NAND_ECC_NONE;
	oob_config = oobsel->eccpos;

	/* 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;
	eccbytes = this->eccbytes;
	
	if ((eccmode == NAND_ECC_NONE) || (this->options & NAND_HWECC_SYNDROME))
		compareecc = 0;

	oobreadlen = mtd->oobsize;
	if (this->options & NAND_HWECC_SYNDROME) 
		oobreadlen -= oobsel->eccbytes;

	/* Loop until all data read */
	while (read < len) {
		
		int aligned = (!col && (len - read) >= end);
		/* 
		 * If the read is not page aligned, we have to read into data buffer
		 * due to ecc, else we read into return buffer direct
		 */
		if (aligned)
			data_poi = &buf[read];
		else 
			data_poi = this->data_buf;
		
		/* Check, if we have this page in the buffer 
		 *
		 * FIXME: Make it work when we must provide oob data too,
		 * check the usage of data_buf oob field
		 */
		if (realpage == this->pagebuf && !oob_buf) {
			/* aligned read ? */
			if (aligned)
				memcpy (data_poi, this->data_buf, end);
			goto readdata;
		}

		/* Check, if we must send the read command */
		if (sndcmd) {
			this->cmdfunc (mtd, NAND_CMD_READ0, 0x00, page);
			sndcmd = 0;
		}	

		/* get oob area, if we have no oob buffer from fs-driver */
		if (!oob_buf || oobsel->useecc == MTD_NANDECC_AUTOPLACE ||
			oobsel->useecc == MTD_NANDECC_AUTOPL_USR)
			oob_data = &this->data_buf[end];

		eccsteps = this->eccsteps;
		
		switch (eccmode) {
		case NAND_ECC_NONE: {	/* No ECC, Read in a page */
			static unsigned long lastwhinge = 0;
			if ((lastwhinge / HZ) != (jiffies / HZ)) {
				printk (KERN_WARNING "Reading data from NAND FLASH without ECC is not recommended\n");
				lastwhinge = jiffies;
			}
			this->read_buf(mtd, data_poi, end);
			break;
		}
			
		case NAND_ECC_SOFT:	/* Software ECC 3/256: Read in a page + oob data */
			this->read_buf(mtd, data_poi, end);
			for (i = 0, datidx = 0; eccsteps; eccsteps--, i+=3, datidx += ecc) 
				this->calculate_ecc(mtd, &data_poi[datidx], &ecc_calc[i]);
			break;	

		default:
			for (i = 0, datidx = 0; eccsteps; eccsteps--, i+=eccbytes, datidx += ecc) {
				this->enable_hwecc(mtd, NAND_ECC_READ);
				this->read_buf(mtd, &data_poi[datidx], ecc);

				/* HW ecc with syndrome calculation must read the
				 * syndrome from flash immidiately after the data */
				if (!compareecc) {
					/* Some hw ecc generators need to know when the
					 * syndrome is read from flash */
					this->enable_hwecc(mtd, NAND_ECC_READSYN);
					this->read_buf(mtd, &oob_data[i], eccbytes);
					/* We calc error correction directly, it checks the hw
					 * generator for an error, reads back the syndrome and
					 * does the error correction on the fly */
					ecc_status = this->correct_data(mtd, &data_poi[datidx], &oob_data[i], &ecc_code[i]);
					if ((ecc_status == -1) || (ecc_status > (flags && 0xff))) {
						DEBUG (MTD_DEBUG_LEVEL0, "nand_read_ecc: " 
							"Failed ECC read, page 0x%08x on chip %d\n", page, chipnr);
						ecc_failed++;
					}
				} else {
					this->calculate_ecc(mtd, &data_poi[datidx], &ecc_calc[i]);
				}	
			}
			break;						
		}

		/* read oobdata */
		this->read_buf(mtd, &oob_data[mtd->oobsize - oobreadlen], oobreadlen);

		/* Skip ECC check, if not requested (ECC_NONE or HW_ECC with syndromes) */
		if (!compareecc)
			goto readoob;	
		
		/* Pick the ECC bytes out of the oob data */
		for (j = 0; j < oobsel->eccbytes; j++)
			ecc_code[j] = oob_data[oob_config[j]];

		/* correct data, if neccecary */
		for (i = 0, j = 0, datidx = 0; i < this->eccsteps; i++, datidx += ecc) {
			ecc_status = this->correct_data(mtd, &data_poi[datidx], &ecc_code[j], &ecc_calc[j]);
			
			/* Get next chunk of ecc bytes */
			j += eccbytes;
			
			/* Check, if we have a fs supplied oob-buffer, 
			 * This is the legacy mode. Used by YAFFS1
			 * Should go away some day
			 */
			if (oob_buf && oobsel->useecc == MTD_NANDECC_PLACE) { 
				int *p = (int *)(&oob_data[mtd->oobsize]);
				p[i] = ecc_status;
			}
			
			if ((ecc_status == -1) || (ecc_status > (flags && 0xff))) {	
				DEBUG (MTD_DEBUG_LEVEL0, "nand_read_ecc: " "Failed ECC read, page 0x%08x\n", page);
				ecc_failed++;
			}
		}		

	readoob:
		/* check, if we have a fs supplied oob-buffer */
		if (oob_buf) {
			/* without autoplace. Legacy mode used by YAFFS1 */
			switch(oobsel->useecc) {
			case MTD_NANDECC_AUTOPLACE:
			case MTD_NANDECC_AUTOPL_USR:
				/* 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);