Received-SPF: pass (google.com: domain of linux-kernel+bounces-181090-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Thu, 16 May 2024 15:09:25 +0200
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Richard
 Weinberger <richard@nod.at>
Subject: Re: [PATCH] mtd: rawnand: onfi: read parameter pages in one go
Message-ID: <20240516150925.5c65319b@xps-13>
In-Reply-To: <ZkXylC2xrlqGW_xV@pengutronix.de>
References: <20240514134140.1050141-1-s.hauer@pengutronix.de>
	<20240516101350.78e5ee29@xps-13>
	<20240516115812.02908822@xps-13>
	<ZkXylC2xrlqGW_xV@pengutronix.de>
Organization: Bootlin
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Hi Sascha,

> > > > nand_read_data_op() is not supported by all NAND controllers.
> > > > nand_change_read_column_op() is not supported or at least is hard to
> > > > support by NAND controllers that use a different page layout than
> > > > expected by the NAND core.   =20
> > >=20
> > > I'm sorry but RNDOUT is not so hard to support, and I know no NAND
> > > controller without this feature (I think even the first mxc controller
> > > supports it?). However, the command does not exist on small page NANDs
> > > (512 bytes). =20
> >=20
> > Nevermind, the ONFI spec (in all versions) states that RNDOUT are
> > allowed during parameter page reads, regardless of the size of the chip
> > (at least, that is not mentioned). =20
>=20
> I could imagine that there are no ONFI compliant chips with small pages,
> I don't know how to verify this though.
>=20
> Anyway, this was a try to make reading the parameter pages a bit more
> straight forward. It seems the MXC NAND controller can't support reading
> three parameter pages in one go either. It works in software ECC mode
> because I reverse the syndome type layout the controller introduces, but
> it can't work with hardware ECC.

Hardware ECC should not be used at this step and should be disabled.
There should not be any ECC interference.

> So disregard this patch.

I now have a proposal, I'll send a v2 of my previous series.

Thanks,
Miqu=C3=A8l