Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 657f28f8 authored by Huang Shijie's avatar Huang Shijie Committed by David Woodhouse
Browse files

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: default avatarHuang Shijie <shijie8@gmail.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 8da28681

drivers/mtd/nand/Kconfig

+0 −9
Original line number Diff line number Diff line
@@ -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

drivers/mtd/nand/ams-delta.c

+0 −13
Original line number Diff line number Diff line
@@ -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;

drivers/mtd/nand/au1550nd.c

+0 −46
Original line number Diff line number Diff line
@@ -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) {

drivers/mtd/nand/bcm_umi_nand.c

+0 −22
Original line number Diff line number Diff line
@@ -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;

drivers/mtd/nand/cafe_nand.c

+0 −7
Original line number Diff line number Diff line
@@ -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;

}