Re: [PATCH 08/13] mtd: spinand: Reject 8D-8D-8D op_templates if octal_dtr_enale() is missing in manufacturer_op

[Apurva Nandan]

On 07/08/21 12:31 am, Miquel Raynal wrote:
> Hi Apurva,
>
> Apurva Nandan <a-nandan@xxxxxx> wrote on Tue, 13 Jul 2021 13:05:33
> +0000:
>
> > The SPI NAND core doesn't know how to switch the flash to Octal DTR
> > mode (i.e. which operations to perform). If the manufacturer hasn't
> > implemented the octal_dtr_enable() manufacturer_op, the SPI NAND core
> > wouldn't be able to switch to 8D-8D-8D mode and will also not be able
> > to run in 1S-1S-1S mode due to already selected 8D-8D-8D read/write
> > cache op_templates.
> >
> > So, avoid choosing a Octal DTR SPI op_template for read_cache,
> > write_cache and update_cache operations, if the manufacturer_op
> > octal_dtr_enable() is missing.
>
> After looking at your previous commit I don't see why this patch would
> be needed. octal_dtr_enable() only updates the mode when it succeeds so
> I don't think this patch is really needed.

I added it to prevent any errors happening dues to a missing 
implementation of octal_dtr_enable() from manufacturer driver side.
So, if the manufacturers skips the octal_dtr_enable() implementation, we 
want the spinand core to run in 1s-1s-1s mode.

Read/write/update op variant selection happens in select_op_variant(), 
much before octal_dtr_enable(). So just check if there is a definition 
of octal_dtr_enable in manufacturer ops and then only use 8D op variants.

Removing this wouldn't break anything in the current implementation.
Do you think we should drop this?

> > Signed-off-by: Apurva Nandan <a-nandan@xxxxxx>
> > ---
> >   drivers/mtd/nand/spi/core.c | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> > index 19d8affac058..8711e887b795 100644
> > --- a/drivers/mtd/nand/spi/core.c
> > +++ b/drivers/mtd/nand/spi/core.c
> > @@ -1028,6 +1028,8 @@ static int spinand_manufacturer_match(struct spinand_device *spinand,
> >   		if (id[0] != manufacturer->id)
> >   			continue;
> >   
> > +		spinand->manufacturer = manufacturer;
> > +
> >   		ret = spinand_match_and_init(spinand,
> >   					     manufacturer->chips,
> >   					     manufacturer->nchips,
> > @@ -1035,7 +1037,6 @@ static int spinand_manufacturer_match(struct spinand_device *spinand,
> >   		if (ret < 0)
> >   			continue;
> >   
> > -		spinand->manufacturer = manufacturer;
> >   		return 0;
> >   	}
> >   	return -ENOTSUPP;
> > @@ -1097,6 +1098,10 @@ spinand_select_op_variant(struct spinand_device *spinand,
> >   		unsigned int nbytes;
> >   		int ret;
> >   
> > +		if (spinand_op_is_octal_dtr(&op) &&
> > +		    !spinand->manufacturer->ops->octal_dtr_enable)
> > +			continue;
> > +
> >   		nbytes = nanddev_per_page_oobsize(nand) +
> >   			 nanddev_page_size(nand);
> >   
>
> Thanks,
> Miquèl
>
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Thanks,
Apurva Nandan