From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: "Álvaro Fernández Rojas" <noltari@gmail.com>,
richard@nod.at, vigneshr@ti.com, s.hauer@pengutronix.de,
masonccyang@mxic.com.tw, christophe.kerello@st.com,
stefan@agner.ch, piotrs@cadence.com, devik@eaxlabs.cz,
tglx@linutronix.de, linux-mtd@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nand: raw: use write_oob_raw for MTD_OPS_AUTO_OOB mode
Date: Mon, 11 May 2020 18:29:23 +0200 [thread overview]
Message-ID: <20200511182923.6a4961ab@xps13> (raw)
In-Reply-To: <20200504123237.5c128668@collabora.com>
Hello,
Boris Brezillon <boris.brezillon@collabora.com> wrote on Mon, 4 May
2020 12:32:37 +0200:
> On Mon, 4 May 2020 11:42:53 +0200
> Álvaro Fernández Rojas <noltari@gmail.com> wrote:
>
> > Some NAND controllers change the ECC bytes when OOB is written with ECC
> > enabled.
> > This is a problem in brcmnand, since adding JFFS2 cleanmarkers after the page
> > has been erased will change the ECC bytes to 0 and the controller will think
> > the block is bad.
> > It can be fixed by using write_oob_raw, which ensures ECC is disabled.
> >
> > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> > ---
> > drivers/mtd/nand/raw/nand_base.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> > index c24e5e2ba130..755d25200520 100644
> > --- a/drivers/mtd/nand/raw/nand_base.c
> > +++ b/drivers/mtd/nand/raw/nand_base.c
> > @@ -488,7 +488,7 @@ static int nand_do_write_oob(struct nand_chip *chip, loff_t to,
> >
> > nand_fill_oob(chip, ops->oobbuf, ops->ooblen, ops);
> >
> > - if (ops->mode == MTD_OPS_RAW)
> > + if (ops->mode == MTD_OPS_AUTO_OOB || ops->mode == MTD_OPS_RAW)
> > status = chip->ecc.write_oob_raw(chip, page & chip->pagemask);
>
> The doc says:
>
> @MTD_OPS_PLACE_OOB: OOB data are placed at the given offset (default)
> @MTD_OPS_AUTO_OOB: OOB data are automatically placed at the free areas
> which are defined by the internal ecclayout
> @MTD_OPS_RAW: data are transferred as-is, with no error
> correction; this mode implies %MTD_OPS_PLACE_OOB
>
> To me, that means MTD_OPS_PLACE_OOB and MTD_OPS_AUTO_OOB do not imply
> MTD_OPS_RAW. Anyway those modes are just too vague. We really should
> separate the ECC-disabled/ECC-enabled concept (AKA raw vs non-raw mode)
> from the OOB placement scheme. IIRC, Miquel had a patchset doing that.
>
> We also should have the concept of protected OOB-region vs
> unprotected-OOB-region if we want JFFS2 to work with controllers that
> protect part of the OOB region. Once we have that we can patch JFFS2
> to write things with "ECC-disabled"+"auto-OOB-placement-on-unprotected
> area".
I see the problem but as Boris said the fix is not valid as-is.
Problem is: I don't have a better proposal yet.
Is forcing JFFS2 to write cleanmarkers in raw mode only an option?
next prev parent reply other threads:[~2020-05-11 16:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-04 9:42 [PATCH] nand: raw: use write_oob_raw for MTD_OPS_AUTO_OOB mode Álvaro Fernández Rojas
2020-05-04 10:32 ` Boris Brezillon
2020-05-11 16:29 ` Miquel Raynal [this message]
2020-05-12 8:36 ` Álvaro Fernández Rojas
2020-05-12 8:44 ` Miquel Raynal
2020-05-12 8:54 ` Boris Brezillon
2020-06-05 17:09 ` Álvaro Fernández Rojas
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