linux-kernel - Re: [PATCH v3 10/10] mtd: rawnand: brcmnand: allow for on-die ecc

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

Hi Miquèl,

On Wed, Jan 24, 2024 at 9:40 AM Miquel Raynal <miquel.raynal@...tlin.com> wrote:
>
> Hi David,
>
> dregan@...adcom.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@...adcom.com>
> > Reviewed-by: William Zhang <william.zhang@...adcom.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/nand/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_host *host)
> >       cfg->blk_adr_bytes = get_blk_adr_bytes(mtd->size, mtd->writesize);
> >
> >       if (chip->ecc.engine_type != 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 to 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 == NAND_ECC_ALGO_UNKNOWN) {
> > @@ -2797,7 +2799,11 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
> >       if (ret)
> >               return ret;
> >
> > -     brcmnand_set_ecc_enabled(host, 1);
> > +     if (chip->ecc.engine_type == 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,
> Miquèl

Thanks!

-Dave