mtd: kill MTD_NAND_VERIFY_WRITE

Just as Artem suggested: "Both UBI and JFFS2 are able to read verify what they wrote already. There are also MTD tests which do this verification. So I think there is no reason to keep this in the NAND layer, let alone wasting RAM in the driver to support this feature. Besides, it does not work for sub-pages and many drivers have it broken. It hurts more than it provides benefits." So kill MTD_NAND_VERIFY_WRITE entirely. Signed-off-by: Huang Shijie <shijie8@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
git-mirror · Sep 29, 2012 · 657f28f · 657f28f
1 parent 8da2868
commit 657f28f
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diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
@@ -22,15 +22,6 @@ menuconfig MTD_NAND
 
 if MTD_NAND
 
-config MTD_NAND_VERIFY_WRITE
-	bool "Verify NAND page writes"
-	help
-	  This adds an extra check when data is written to the flash. The
-	  NAND flash device internally checks only bits transitioning
-	  from 1 to 0. There is a rare possibility that even though the
-	  device thinks the write was successful, a bit could have been
-	  flipped accidentally due to device wear or something else.
-
 config MTD_NAND_BCH
 	tristate
 	select BCH

diff --git a/drivers/mtd/nand/ams-delta.c b/drivers/mtd/nand/ams-delta.c
@@ -103,18 +103,6 @@ static void ams_delta_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 		buf[i] = ams_delta_read_byte(mtd);
 }
 
-static int ams_delta_verify_buf(struct mtd_info *mtd, const u_char *buf,
-				int len)
-{
-	int i;
-
-	for (i=0; i<len; i++)
-		if (buf[i] != ams_delta_read_byte(mtd))
-			return -EFAULT;
-
-	return 0;
-}
-
 /*
  * Command control function
  *
@@ -233,7 +221,6 @@ static int __devinit ams_delta_init(struct platform_device *pdev)
 	this->read_byte = ams_delta_read_byte;
 	this->write_buf = ams_delta_write_buf;
 	this->read_buf = ams_delta_read_buf;
-	this->verify_buf = ams_delta_verify_buf;
 	this->cmd_ctrl = ams_delta_hwcontrol;
 	if (gpio_request(AMS_DELTA_GPIO_PIN_NAND_RB, "nand_rdy") == 0) {
 		this->dev_ready = ams_delta_nand_ready;

diff --git a/drivers/mtd/nand/au1550nd.c b/drivers/mtd/nand/au1550nd.c
@@ -140,28 +140,6 @@ static void au_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 	}
 }
 
-/**
- * au_verify_buf -  Verify chip data against buffer
- * @mtd:	MTD device structure
- * @buf:	buffer containing the data to compare
- * @len:	number of bytes to compare
- *
- * verify function for 8bit buswidth
- */
-static int au_verify_buf(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	int i;
-	struct nand_chip *this = mtd->priv;
-
-	for (i = 0; i < len; i++) {
-		if (buf[i] != readb(this->IO_ADDR_R))
-			return -EFAULT;
-		au_sync();
-	}
-
-	return 0;
-}
-
 /**
  * au_write_buf16 -  write buffer to chip
  * @mtd:	MTD device structure
@@ -205,29 +183,6 @@ static void au_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
 	}
 }
 
-/**
- * au_verify_buf16 -  Verify chip data against buffer
- * @mtd:	MTD device structure
- * @buf:	buffer containing the data to compare
- * @len:	number of bytes to compare
- *
- * verify function for 16bit buswidth
- */
-static int au_verify_buf16(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	int i;
-	struct nand_chip *this = mtd->priv;
-	u16 *p = (u16 *) buf;
-	len >>= 1;
-
-	for (i = 0; i < len; i++) {
-		if (p[i] != readw(this->IO_ADDR_R))
-			return -EFAULT;
-		au_sync();
-	}
-	return 0;
-}
-
 /* Select the chip by setting nCE to low */
 #define NAND_CTL_SETNCE		1
 /* Deselect the chip by setting nCE to high */
@@ -516,7 +471,6 @@ static int __devinit au1550nd_probe(struct platform_device *pdev)
 	this->read_word = au_read_word;
 	this->write_buf = (pd->devwidth) ? au_write_buf16 : au_write_buf;
 	this->read_buf = (pd->devwidth) ? au_read_buf16 : au_read_buf;
-	this->verify_buf = (pd->devwidth) ? au_verify_buf16 : au_verify_buf;
 
 	ret = nand_scan(&ctx->info, 1);
 	if (ret) {

diff --git a/drivers/mtd/nand/bcm_umi_nand.c b/drivers/mtd/nand/bcm_umi_nand.c
@@ -332,27 +332,6 @@ static void bcm_umi_nand_read_buf(struct mtd_info *mtd, u_char * buf, int len)
 #endif
 }
 
-static uint8_t readbackbuf[NAND_MAX_PAGESIZE];
-static int bcm_umi_nand_verify_buf(struct mtd_info *mtd, const u_char * buf,
-				   int len)
-{
-	/*
-	 * Try to readback page with ECC correction. This is necessary
-	 * for MLC parts which may have permanently stuck bits.
-	 */
-	struct nand_chip *chip = mtd->priv;
-	int ret = chip->ecc.read_page(mtd, chip, readbackbuf, 0, 0);
-	if (ret < 0)
-		return -EFAULT;
-	else {
-		if (memcmp(readbackbuf, buf, len) == 0)
-			return 0;
-
-		return -EFAULT;
-	}
-	return 0;
-}
-
 static int __devinit bcm_umi_nand_probe(struct platform_device *pdev)
 {
 	struct nand_chip *this;
@@ -416,7 +395,6 @@ static int __devinit bcm_umi_nand_probe(struct platform_device *pdev)
 
 	this->write_buf = bcm_umi_nand_write_buf;
 	this->read_buf = bcm_umi_nand_read_buf;
-	this->verify_buf = bcm_umi_nand_verify_buf;
 
 	this->cmd_ctrl = bcm_umi_nand_hwcontrol;
 	this->ecc.mode = NAND_ECC_HW;

diff --git a/drivers/mtd/nand/cafe_nand.c b/drivers/mtd/nand/cafe_nand.c
@@ -576,13 +576,6 @@ static int cafe_nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 		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;
 }
 

diff --git a/drivers/mtd/nand/cmx270_nand.c b/drivers/mtd/nand/cmx270_nand.c
@@ -76,18 +76,6 @@ static void cmx270_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 		*buf++ = readl(this->IO_ADDR_R) >> 16;
 }
 
-static int cmx270_verify_buf(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	int i;
-	struct nand_chip *this = mtd->priv;
-
-	for (i=0; i<len; i++)
-		if (buf[i] != (u_char)(readl(this->IO_ADDR_R) >> 16))
-			return -EFAULT;
-
-	return 0;
-}
-
 static inline void nand_cs_on(void)
 {
 	gpio_set_value(GPIO_NAND_CS, 0);
@@ -209,7 +197,6 @@ static int __init cmx270_init(void)
 	this->read_byte = cmx270_read_byte;
 	this->read_buf = cmx270_read_buf;
 	this->write_buf = cmx270_write_buf;
-	this->verify_buf = cmx270_verify_buf;
 
 	/* Scan to find existence of the device */
 	if (nand_scan (cmx270_nand_mtd, 1)) {

diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
@@ -376,19 +376,6 @@ static void doc2000_readbuf_dword(struct mtd_info *mtd, u_char *buf, int len)
 	}
 }
 
-static int doc2000_verifybuf(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	struct nand_chip *this = mtd->priv;
-	struct doc_priv *doc = this->priv;
-	void __iomem *docptr = doc->virtadr;
-	int i;
-
-	for (i = 0; i < len; i++)
-		if (buf[i] != ReadDOC(docptr, 2k_CDSN_IO))
-			return -EFAULT;
-	return 0;
-}
-
 static uint16_t __init doc200x_ident_chip(struct mtd_info *mtd, int nr)
 {
 	struct nand_chip *this = mtd->priv;
@@ -526,26 +513,6 @@ static void doc2001_readbuf(struct mtd_info *mtd, u_char *buf, int len)
 	buf[i] = ReadDOC(docptr, LastDataRead);
 }
 
-static int doc2001_verifybuf(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	struct nand_chip *this = mtd->priv;
-	struct doc_priv *doc = this->priv;
-	void __iomem *docptr = doc->virtadr;
-	int i;
-
-	/* Start read pipeline */
-	ReadDOC(docptr, ReadPipeInit);
-
-	for (i = 0; i < len - 1; i++)
-		if (buf[i] != ReadDOC(docptr, Mil_CDSN_IO)) {
-			ReadDOC(docptr, LastDataRead);
-			return i;
-		}
-	if (buf[i] != ReadDOC(docptr, LastDataRead))
-		return i;
-	return 0;
-}
-
 static u_char doc2001plus_read_byte(struct mtd_info *mtd)
 {
 	struct nand_chip *this = mtd->priv;
@@ -610,33 +577,6 @@ static void doc2001plus_readbuf(struct mtd_info *mtd, u_char *buf, int len)
 		printk("\n");
 }
 
-static int doc2001plus_verifybuf(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	struct nand_chip *this = mtd->priv;
-	struct doc_priv *doc = this->priv;
-	void __iomem *docptr = doc->virtadr;
-	int i;
-
-	if (debug)
-		printk("verifybuf of %d bytes: ", len);
-
-	/* Start read pipeline */
-	ReadDOC(docptr, Mplus_ReadPipeInit);
-	ReadDOC(docptr, Mplus_ReadPipeInit);
-
-	for (i = 0; i < len - 2; i++)
-		if (buf[i] != ReadDOC(docptr, Mil_CDSN_IO)) {
-			ReadDOC(docptr, Mplus_LastDataRead);
-			ReadDOC(docptr, Mplus_LastDataRead);
-			return i;
-		}
-	if (buf[len - 2] != ReadDOC(docptr, Mplus_LastDataRead))
-		return len - 2;
-	if (buf[len - 1] != ReadDOC(docptr, Mplus_LastDataRead))
-		return len - 1;
-	return 0;
-}
-
 static void doc2001plus_select_chip(struct mtd_info *mtd, int chip)
 {
 	struct nand_chip *this = mtd->priv;
@@ -1432,7 +1372,6 @@ static inline int __init doc2000_init(struct mtd_info *mtd)
 	this->read_byte = doc2000_read_byte;
 	this->write_buf = doc2000_writebuf;
 	this->read_buf = doc2000_readbuf;
-	this->verify_buf = doc2000_verifybuf;
 	this->scan_bbt = nftl_scan_bbt;
 
 	doc->CDSNControl = CDSN_CTRL_FLASH_IO | CDSN_CTRL_ECC_IO;
@@ -1449,7 +1388,6 @@ static inline int __init doc2001_init(struct mtd_info *mtd)
 	this->read_byte = doc2001_read_byte;
 	this->write_buf = doc2001_writebuf;
 	this->read_buf = doc2001_readbuf;
-	this->verify_buf = doc2001_verifybuf;
 
 	ReadDOC(doc->virtadr, ChipID);
 	ReadDOC(doc->virtadr, ChipID);
@@ -1480,7 +1418,6 @@ static inline int __init doc2001plus_init(struct mtd_info *mtd)
 	this->read_byte = doc2001plus_read_byte;
 	this->write_buf = doc2001plus_writebuf;
 	this->read_buf = doc2001plus_readbuf;
-	this->verify_buf = doc2001plus_verifybuf;
 	this->scan_bbt = inftl_scan_bbt;
 	this->cmd_ctrl = NULL;
 	this->select_chip = doc2001plus_select_chip;

diff --git a/drivers/mtd/nand/fsl_elbc_nand.c b/drivers/mtd/nand/fsl_elbc_nand.c
@@ -614,41 +614,6 @@ static void fsl_elbc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
 		        len, avail);
 }
 
-/*
- * Verify buffer against the FCM Controller Data Buffer
- */
-static int fsl_elbc_verify_buf(struct mtd_info *mtd, const u_char *buf, int len)
-{
-	struct nand_chip *chip = mtd->priv;
-	struct fsl_elbc_mtd *priv = chip->priv;
-	struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = priv->ctrl->nand;
-	int i;
-
-	if (len < 0) {
-		dev_err(priv->dev, "write_buf of %d bytes", len);
-		return -EINVAL;
-	}
-
-	if ((unsigned int)len >
-			elbc_fcm_ctrl->read_bytes - elbc_fcm_ctrl->index) {
-		dev_err(priv->dev,
-			"verify_buf beyond end of buffer "
-			"(%d requested, %u available)\n",
-			len, elbc_fcm_ctrl->read_bytes - elbc_fcm_ctrl->index);
-
-		elbc_fcm_ctrl->index = elbc_fcm_ctrl->read_bytes;
-		return -EINVAL;
-	}
-
-	for (i = 0; i < len; i++)
-		if (in_8(&elbc_fcm_ctrl->addr[elbc_fcm_ctrl->index + i])
-				!= buf[i])
-			break;
-
-	elbc_fcm_ctrl->index += len;
-	return i == len && elbc_fcm_ctrl->status == LTESR_CC ? 0 : -EIO;
-}
-
 /* This function is called after Program and Erase Operations to
  * check for success or failure.
  */
@@ -798,7 +763,6 @@ static int fsl_elbc_chip_init(struct fsl_elbc_mtd *priv)
 	chip->read_byte = fsl_elbc_read_byte;
 	chip->write_buf = fsl_elbc_write_buf;
 	chip->read_buf = fsl_elbc_read_buf;
-	chip->verify_buf = fsl_elbc_verify_buf;
 	chip->select_chip = fsl_elbc_select_chip;
 	chip->cmdfunc = fsl_elbc_cmdfunc;
 	chip->waitfunc = fsl_elbc_wait;

diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
@@ -626,46 +626,6 @@ static void fsl_ifc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
 			__func__, len, avail);
 }
 
-/*
- * Verify buffer against the IFC Controller Data Buffer
- */
-static int fsl_ifc_verify_buf(struct mtd_info *mtd,
-			       const u_char *buf, int len)
-{
-	struct nand_chip *chip = mtd->priv;
-	struct fsl_ifc_mtd *priv = chip->priv;
-	struct fsl_ifc_ctrl *ctrl = priv->ctrl;
-	struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;
-	int i;
-
-	if (len < 0) {
-		dev_err(priv->dev, "%s: write_buf of %d bytes", __func__, len);
-		return -EINVAL;
-	}
-
-	if ((unsigned int)len > nctrl->read_bytes - nctrl->index) {
-		dev_err(priv->dev,
-			"%s: beyond end of buffer (%d requested, %u available)\n",
-			__func__, len, nctrl->read_bytes - nctrl->index);
-
-		nctrl->index = nctrl->read_bytes;
-		return -EINVAL;
-	}
-
-	for (i = 0; i < len; i++)
-		if (in_8(&nctrl->addr[nctrl->index + i]) != buf[i])
-			break;
-
-	nctrl->index += len;
-
-	if (i != len)
-		return -EIO;
-	if (ctrl->nand_stat != IFC_NAND_EVTER_STAT_OPC)
-		return -EIO;
-
-	return 0;
-}
-
 /*
  * This function is called after Program and Erase Operations to
  * check for success or failure.
@@ -796,7 +756,6 @@ static int fsl_ifc_chip_init(struct fsl_ifc_mtd *priv)
 
 	chip->write_buf = fsl_ifc_write_buf;
 	chip->read_buf = fsl_ifc_read_buf;
-	chip->verify_buf = fsl_ifc_verify_buf;
 	chip->select_chip = fsl_ifc_select_chip;
 	chip->cmdfunc = fsl_ifc_cmdfunc;
 	chip->waitfunc = fsl_ifc_wait;