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From: David Regan <dregan@broadcom.com>
Date: Thu, 25 Jan 2024 11:47:46 -0800
Message-ID: <CAA_RMS42FaiN+Za1iY12o0YUANH9rJarBTBa=9jNn8x6_g-Fng@mail.gmail.com>
Subject: Re: [PATCH v3 10/10] mtd: rawnand: brcmnand: allow for on-die ecc
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: David Regan <dregan@broadcom.com>, dregan@mail.com, 
	Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com>, robh+dt@kernel.org, 
	krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, 
	computersforpeace@gmail.com, kdasu.kdev@gmail.com, 
	linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, 
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Joel Peshkin <joel.peshkin@broadcom.com>, 
	Tomer Yacoby <tomer.yacoby@broadcom.com>, Dan Beygelman <dan.beygelman@broadcom.com>, 
	William Zhang <william.zhang@broadcom.com>, Anand Gore <anand.gore@broadcom.com>, 
	Kursad Oney <kursad.oney@broadcom.com>, Florian Fainelli <florian.fainelli@broadcom.com>, 
	rafal@milecki.pl, bcm-kernel-feedback-list@broadcom.com, 
	andre.przywara@arm.com, baruch@tkos.co.il, 
	linux-arm-kernel@lists.infradead.org, 
	Dan Carpenter <dan.carpenter@linaro.org>
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Hi Miqu=C3=A8l,

On Wed, Jan 24, 2024 at 9:40=E2=80=AFAM Miquel Raynal <miquel.raynal@bootli=
n.com> wrote:
>
> Hi David,
>
> dregan@broadcom.com wrote on Tue, 23 Jan 2024 19:04:58 -0800:
>
> > Allow settings for on-die ecc such that if on-die ECC is selected
> > don't error out but require ECC strap setting of zero
> >
> > Signed-off-by: David Regan <dregan@broadcom.com>
> > Reviewed-by: William Zhang <william.zhang@broadcom.com>
> > ---
> > Changes in v3: None
> > ---
> > Changes in v2:
> > - Added to patch series
> > ---
> >  drivers/mtd/nand/raw/brcmnand/brcmnand.c | 14 ++++++++++----
> >  1 file changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nan=
d/raw/brcmnand/brcmnand.c
> > index a4e311b6798c..42526f3250c9 100644
> > --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > @@ -2727,9 +2727,11 @@ static int brcmnand_setup_dev(struct brcmnand_ho=
st *host)
> >       cfg->blk_adr_bytes =3D get_blk_adr_bytes(mtd->size, mtd->writesiz=
e);
> >
> >       if (chip->ecc.engine_type !=3D NAND_ECC_ENGINE_TYPE_ON_HOST) {
> > -             dev_err(ctrl->dev, "only HW ECC supported; selected: %d\n=
",
> > -                     chip->ecc.engine_type);
> > -             return -EINVAL;
> > +             if (chip->ecc.strength) {
> > +                     dev_err(ctrl->dev, "ERROR!!! HW ECC must be set t=
o zero for non-hardware ECC; selected: %d\n",
> > +                             chip->ecc.strength);
>
> Can you use a more formal string? Also clarify it because I don't
> really understand what it leads to.

How about:

dev_err(ctrl->dev, "HW ECC set to %d, must be zero for on-die ECC\n",

>
> > +                     return -EINVAL;
> > +             }
> >       }
> >
> >       if (chip->ecc.algo =3D=3D NAND_ECC_ALGO_UNKNOWN) {
> > @@ -2797,7 +2799,11 @@ static int brcmnand_setup_dev(struct brcmnand_ho=
st *host)
> >       if (ret)
> >               return ret;
> >
> > -     brcmnand_set_ecc_enabled(host, 1);
> > +     if (chip->ecc.engine_type =3D=3D NAND_ECC_ENGINE_TYPE_ON_DIE) {
> > +             dev_dbg(ctrl->dev, "Disable HW ECC for on-die ECC\n");
>
> Not needed.

Will remove.

>
> > +             brcmnand_set_ecc_enabled(host, 0);
> > +     } else
> > +             brcmnand_set_ecc_enabled(host, 1);
>
> Style is wrong, but otherwise I think ECC should be kept disabled while
> not in active use, so I am a bit surprised by this line.

This is a double check to turn on/off our hardware ECC.

>
> >
> >       brcmnand_print_cfg(host, msg, cfg);
> >       dev_info(ctrl->dev, "detected %s\n", msg);
>
>
> Thanks,
> Miqu=C3=A8l

Thanks!

-Dave