[PATCH v2] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg

[PATCH v2] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg

[Boris Brezillon]

NAND chips require a bit of time to take the NAND operation into
account and set the BUSY bit in the STATUS reg. Make sure we don't poll
the STATUS reg too early in nand_soft_waitrdy().

Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
---
Changes in v2:
- Move the ndelay() to nand_soft_waitrdy() instead of having it in the
  FSMC driver
---
 drivers/mtd/nand/raw/nand_base.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 72f3a89da513..da94fcb4dd9b 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -706,12 +706,17 @@ static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
  */
 int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms)
 {
+	const struct nand_sdr_timings *timings;
 	u8 status = 0;
 	int ret;
 
 	if (!chip->exec_op)
 		return -ENOTSUPP;
 
+	/* Wait tWB before polling the STATUS reg. */
+	timings = nand_get_sdr_timings(&chip->data_interface);
+	ndelay(PSEC_TO_NSEC(sdr->tWB_max));
+
 	ret = nand_status_op(chip, NULL);
 	if (ret)
 		return ret;
-- 
2.14.1

Re: [PATCH v2] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg

[Miquel Raynal]

Hi Boris,

On Fri,  4 May 2018 21:24:31 +0200, Boris Brezillon
<boris.brezillon@bootlin.com> wrote:

> NAND chips require a bit of time to take the NAND operation into
> account and set the BUSY bit in the STATUS reg. Make sure we don't poll
> the STATUS reg too early in nand_soft_waitrdy().
> 
> Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miquèl

-- 
Miquel Raynal, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v2] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg

[Boris Brezillon]

On Fri,  4 May 2018 21:24:31 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:

> NAND chips require a bit of time to take the NAND operation into
> account and set the BUSY bit in the STATUS reg. Make sure we don't poll
> the STATUS reg too early in nand_soft_waitrdy().
> 
> Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> ---
> Changes in v2:
> - Move the ndelay() to nand_soft_waitrdy() instead of having it in the
>   FSMC driver
> ---
>  drivers/mtd/nand/raw/nand_base.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 72f3a89da513..da94fcb4dd9b 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -706,12 +706,17 @@ static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
>   */
>  int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms)
>  {
> +	const struct nand_sdr_timings *timings;
>  	u8 status = 0;
>  	int ret;
>  
>  	if (!chip->exec_op)
>  		return -ENOTSUPP;
>  
> +	/* Wait tWB before polling the STATUS reg. */
> +	timings = nand_get_sdr_timings(&chip->data_interface);
> +	ndelay(PSEC_TO_NSEC(sdr->tWB_max));

			    ^ timings->tWB_max

And for those who wonder, yes, I compiled the code, but it seems I
forgot to amend the commit after fixing the bug locally :-).

> +
>  	ret = nand_status_op(chip, NULL);
>  	if (ret)
>  		return ret;

Re: [PATCH v2] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg

[Boris Brezillon]

On Mon, 7 May 2018 11:35:22 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:

> On Fri,  4 May 2018 21:24:31 +0200
> Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> 
> > NAND chips require a bit of time to take the NAND operation into
> > account and set the BUSY bit in the STATUS reg. Make sure we don't poll
> > the STATUS reg too early in nand_soft_waitrdy().
> > 
> > Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation")
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> > ---
> > Changes in v2:
> > - Move the ndelay() to nand_soft_waitrdy() instead of having it in the
> >   FSMC driver
> > ---
> >  drivers/mtd/nand/raw/nand_base.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> > index 72f3a89da513..da94fcb4dd9b 100644
> > --- a/drivers/mtd/nand/raw/nand_base.c
> > +++ b/drivers/mtd/nand/raw/nand_base.c
> > @@ -706,12 +706,17 @@ static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
> >   */
> >  int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms)
> >  {
> > +	const struct nand_sdr_timings *timings;
> >  	u8 status = 0;
> >  	int ret;
> >  
> >  	if (!chip->exec_op)
> >  		return -ENOTSUPP;
> >  
> > +	/* Wait tWB before polling the STATUS reg. */
> > +	timings = nand_get_sdr_timings(&chip->data_interface);
> > +	ndelay(PSEC_TO_NSEC(sdr->tWB_max));  
> 
> 			    ^ timings->tWB_max
> 
> And for those who wonder, yes, I compiled the code, but it seems I
> forgot to amend the commit after fixing the bug locally :-).

Queued to mtd/master after fixing the problem.

> 
> > +
> >  	ret = nand_status_op(chip, NULL);
> >  	if (ret)
> >  		return ret;  
> 
> 
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