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Date:   Wed, 26 Jun 2019 13:27:15 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     Naga Sureshkumar Relli <nagasure@xilinx.com>
Cc:     "miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
        "helmut.grohne@intenta.de" <helmut.grohne@intenta.de>,
        "richard@nod.at" <richard@nod.at>,
        "dwmw2@infradead.org" <dwmw2@infradead.org>,
        "computersforpeace@gmail.com" <computersforpeace@gmail.com>,
        "marek.vasut@gmail.com" <marek.vasut@gmail.com>,
        "vigneshr@ti.com" <vigneshr@ti.com>,
        "bbrezillon@kernel.org" <bbrezillon@kernel.org>,
        "yamada.masahiro@socionext.com" <yamada.masahiro@socionext.com>,
        "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [LINUX PATCH v17 1/2] mtd: rawnand: nand_micron: Do not over
 write driver's read_page()/write_page()
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On Wed, 26 Jun 2019 11:22:33 +0000
Naga Sureshkumar Relli <nagasure@xilinx.com> wrote:

> Hi Boris,
> 
> > -----Original Message-----
> > From: Boris Brezillon <boris.brezillon@collabora.com>
> > Sent: Wednesday, June 26, 2019 12:18 PM
> > To: Naga Sureshkumar Relli <nagasure@xilinx.com>
> > Cc: miquel.raynal@bootlin.com; helmut.grohne@intenta.de; richard@nod.at;
> > dwmw2@infradead.org; computersforpeace@gmail.com; marek.vasut@gmail.com;
> > vigneshr@ti.com; bbrezillon@kernel.org; yamada.masahiro@socionext.com; linux-
> > mtd@lists.infradead.org; linux-kernel@vger.kernel.org
> > Subject: Re: [LINUX PATCH v17 1/2] mtd: rawnand: nand_micron: Do not over write
> > driver's read_page()/write_page()
> > 
> > On Mon, 24 Jun 2019 22:46:29 -0600
> > Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com> wrote:
> >   
> > > Add check before assigning chip->ecc.read_page() and
> > > chip->ecc.write_page()
> > >
> > > Signed-off-by: Naga Sureshkumar Relli
> > > <naga.sureshkumar.relli@xilinx.com>
> > > ---
> > >  drivers/mtd/nand/raw/nand_micron.c | 7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/mtd/nand/raw/nand_micron.c
> > > b/drivers/mtd/nand/raw/nand_micron.c
> > > index cbd4f09ac178..565f2696c747 100644
> > > --- a/drivers/mtd/nand/raw/nand_micron.c
> > > +++ b/drivers/mtd/nand/raw/nand_micron.c
> > > @@ -500,8 +500,11 @@ static int micron_nand_init(struct nand_chip *chip)
> > >  		chip->ecc.size = 512;
> > >  		chip->ecc.strength = chip->base.eccreq.strength;
> > >  		chip->ecc.algo = NAND_ECC_BCH;
> > > -		chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
> > > -		chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
> > > +		if (!chip->ecc.read_page)
> > > +			chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
> > > +
> > > +		if (!chip->ecc.write_page)
> > > +			chip->ecc.write_page = micron_nand_write_page_on_die_ecc;  
> > 
> > That's wrong, if you don't want on-die ECC to be used, simply don't set nand-ecc-mode to "on-
> > die".  
> Ok. But if we want to use on-die ECC then you mean to say it is mandatory to use micron_nand_read/write_page_on_die_ecc()?

Absolutely, and if it doesn't work that means you driver does not
implement raw accesses correctly, which means it's still buggy...