[PATCH] mtd: nand: Wait for PAGEPROG to finish in drivers setting NAND_ECC_CUSTOM_PAGE_ACCESS

[Marc Gonzalez]

On 16/05/2017 18:27, Boris Brezillon wrote:

> Drivers setting NAND_ECC_CUSTOM_PAGE_ACCESS are supposed to handle the
> full read/write page sequence, and waiting for a page to actually be
> programmed is part of this write-page sequence.
> This is also what is done in ->write_oob_xxx() hooks, so let's do that in
> ->write_page_xxx() as well to make it consistent.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> ---
>  drivers/mtd/nand/atmel/nand-controller.c |  6 +++++-
>  drivers/mtd/nand/nand_base.c             | 10 ++++++----
>  drivers/mtd/nand/nand_micron.c           | 10 ++++++++--
>  drivers/mtd/nand/tango_nand.c            | 13 ++++++++++++-
>  4 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 8dafd2a54e11..08ff98c47e1f 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -2574,11 +2574,13 @@ static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
>  	if (status < 0)
>  		return status;
>  
> -	if (nand_standard_page_accessors(&chip->ecc))
> +	if (nand_standard_page_accessors(&chip->ecc)) {
>  		chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
> -	status = chip->waitfunc(mtd, chip);
> -	if (status & NAND_STATUS_FAIL)
> -		return -EIO;
> +
> +		status = chip->waitfunc(mtd, chip);
> +		if (status & NAND_STATUS_FAIL)
> +			return -EIO;
> +	}

AFAIU, the wait operation used to be unconditional;
but it is now skipped for CUSTOM accessors. OK.


> diff --git a/drivers/mtd/nand/tango_nand.c b/drivers/mtd/nand/tango_nand.c
> index a2150b15d4c1..8498fa36e533 100644
> --- a/drivers/mtd/nand/tango_nand.c
> +++ b/drivers/mtd/nand/tango_nand.c
> @@ -295,7 +295,7 @@ static int tango_write_page(struct mtd_info *mtd, struct nand_chip *chip,
>  			    const u8 *buf, int oob_required, int page)
>  {
>  	struct tango_nfc *nfc = to_tango_nfc(chip->controller);
> -	int err, len = mtd->writesize;
> +	int err, status, len = mtd->writesize;
>  
>  	/* Calling tango_write_oob() would send PAGEPROG twice */
>  	if (oob_required)
> @@ -306,6 +306,10 @@ static int tango_write_page(struct mtd_info *mtd, struct nand_chip *chip,
>  	if (err)
>  		return err;
>  
> +	status = chip->waitfunc(mtd, chip);
> +	if (status & NAND_STATUS_FAIL)
> +		return -EIO;
> +
>  	return 0;
>  }

When I introduced the custom_accessors flag, I missed the removal
of this wait operation. The tango NFC is supposed to take care of
everything, from start to finish.

I applied the following patch:

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2675,6 +2675,9 @@ static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
        if (status < 0)
                return status;
 
+       if (!nand_standard_page_accessors(&chip->ecc))
+               return 0;
+

And ran mtd_speedtest. No measurable change.
mtd_stresstest did not detect any issues.

> @@ -423,9 +427,16 @@ static int tango_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
>  static int tango_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
>  				const u8 *buf, int oob_required, int page)
>  {
> +	int status;
> +
>  	chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0, page);
>  	raw_write(chip, buf, chip->oob_poi);
>  	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
> +
> +	status = chip->waitfunc(mtd, chip);
> +	if (status & NAND_STATUS_FAIL)
> +		return -EIO;
> +
>  	return 0;
>  }

This one would still be required, since we're going behind the NFC's back.
Should we test NAND_STATUS_FAIL in tango_write_oob() too?
It might not matter, since you plan to change it to nand_prog_page_end_op()
ultimately.

Regards.