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From:   Sudip Mukherjee <sudip.mukherjee@sifive.com>
Date:   Fri, 22 Jul 2022 11:24:46 +0100
Message-ID: <CAHyZL-c9iSd8=CaQ00Nptea4cqp9f7oqS5VefT3vfcr2J3hmSQ@mail.gmail.com>
Subject: Re: [PATCH 2/3] mtd: spi-nor: add support for Quad Page Program to no_sfdp_flags
To:     Tudor Ambarus <Tudor.Ambarus@microchip.com>
Cc:     Pratyush Yadav <p.yadav@ti.com>, Michael Walle <michael@walle.cc>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Greentime Hu <greentime.hu@sifive.com>,
        Jude Onyenegecha <jude.onyenegecha@sifive.com>,
        William Salmon <william.salmon@sifive.com>,
        Adnan Chowdhury <adnan.chowdhury@sifive.com>,
        Ben Dooks <ben.dooks@sifive.com>,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
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Hi Tudor,

On Mon, Jul 18, 2022 at 7:49 PM Sudip Mukherjee
<sudip.mukherjee@sifive.com> wrote:
>
> On Mon, Jul 18, 2022 at 6:02 PM <Tudor.Ambarus@microchip.com> wrote:
> >
> > On 7/12/22 19:38, Sudip Mukherjee wrote:
> > > [You don't often get email from sudip.mukherjee@sifive.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> > >
> > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> > >
> > > Some flash chips which does not have a SFDP table can support Quad
> > > Input Page Program. Enable it in hwcaps if defined.
> > >
>
> <snip>
>
> > > diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> > > index 58fbedc94080f..dde636bdb1a7c 100644
> > > --- a/drivers/mtd/spi-nor/core.h
> > > +++ b/drivers/mtd/spi-nor/core.h
> > > @@ -462,6 +462,7 @@ struct spi_nor_fixups {
> > >   *   SPI_NOR_OCTAL_READ:      flash supports Octal Read.
> > >   *   SPI_NOR_OCTAL_DTR_READ:  flash supports octal DTR Read.
> > >   *   SPI_NOR_OCTAL_DTR_PP:    flash supports Octal DTR Page Program.
> > > + *   SPI_NOR_QUAD_PP:         flash supports Quad Input Page Program.
> >
> > You don't need this flag if your flash supports the 4-byte Address
> > Instruction Table. Does you flash support it? Can you dump all the
> > SFDP tables, please?
>
> Not sure what the correct way to dump sfdp is. I did this from sysfs.

I tried decoding this SFDP table and I think the parameters table says
it has "3-Byte only addressing".
So, I guess that means it does not support 4-byte Address Instruction
Table. And the datasheet
says it supports "Quad Input Page Program (3-byte Address)".
My existing patchset works for Quad Input Page Program, and I can send
a v2 with the previous
patch and this merged together (as you suggested) or I can try
enabling sfdp for this chip and then use
a fixup_flags to enable "Quad Input Page Program" which I think will
be more complicated.
Which one will you suggest?

--
Regards
Sudip