Re: [PATCH] mtd: rawnand: marvell: pass ms delay to wait_op

Miquel Raynal
2018-05-03T07:05:23Z

Hi Chris,

On Thu, 3 May 2018 05:28:32 +0000, Chris Packham
<Chris.Packham@alliedtelesis.co.nz> wrote:

> On 03/05/18 14:21, Chris Packham wrote:
> > marvell_nfc_wait_op() expects the delay to be expressed in milliseconds
> > but nand_sdr_timings uses picoseconds. Use PSEC_TO_MSEC when passing
> > tPROG_max to marvell_nfc_wait_op().
> >
> > Fixes: 02f26ecf8c772 ("mtd: nand: add reworked Marvell NAND controller driver")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> > ---
> > drivers/mtd/nand/raw/marvell_nand.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> > index 1d779a35ac8e..e4b964fd40d8 100644
> > --- a/drivers/mtd/nand/raw/marvell_nand.c
> > +++ b/drivers/mtd/nand/raw/marvell_nand.c
> > @@ -1074,7 +1074,7 @@ static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
> > return ret;
> >
> > ret = marvell_nfc_wait_op(chip,
> > - chip->data_interface.timings.sdr.tPROG_max);
> > + PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> > return ret;
> > }
> >
> > @@ -1494,7 +1494,7 @@ static int marvell_nfc_hw_ecc_bch_write_page(struct mtd_info *mtd,
> > }
> >
> > ret = marvell_nfc_wait_op(chip,
> > - chip->data_interface.timings.sdr.tPROG_max);
> > + PSEC_TO_MSEC(chip->data_interface.timings.sdr.tPROG_max));
> >
> > marvell_nfc_disable_hw_ecc(chip);
> >
>
> Actually I'm not so sure about this patch. While passing the pico-second
> value for tPROG_max is clearly wrong and leads to seemingly indefinite
> hangs on some systems. Converting the times to micro-seconds leaves us
> with delays that are far too short.

It is not micro but milli-seconds here.

>
> The old pxa3xx driver had hard coded 200ms delays. These delays now work
> out to 1ms which seems every bit as wrong as 600000000ms.

200ms is extremely long, I guess typical values are ~200-500us, so this
1ms timeout does not scare me :)

I'll let Boris conclude.

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

Thanks.

--
Miquel Raynal, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering