From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.bootlin.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fMwVU-0001e6-S6 for linux-mtd@lists.infradead.org; Sun, 27 May 2018 14:18:50 +0000 Date: Sun, 27 May 2018 16:18:32 +0200 From: Miquel Raynal To: Stefan Agner Cc: Boris Brezillon , Benjamin Lindqvist , dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com, thierry.reding@gmail.com, mturquette@baylibre.com, sboyd@kernel.org, Lucas Stach , richard@nod.at, marcel@ziswiler.com, krzk@kernel.org, digetx@gmail.com, jonathanh@nvidia.com, pdeschrijver@nvidia.com, pgaikwad@nvidia.com, Mirza Krak , linux-mtd@lists.infradead.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH 2/5] mtd: rawnand: add NVIDIA Tegra NAND Flash controller driver Message-ID: <20180527161832.1152be6e@xps13> In-Reply-To: <146a3abbbff4dcef30ad662a0fb85ff1@agner.ch> References: <86fdf19ec92b732709732fb60199f16488b4b727.1526990589.git.stefan@agner.ch> <20180524135335.6aa0b7a4@bbrezillon> <146a3abbbff4dcef30ad662a0fb85ff1@agner.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Stefan, On Thu, 24 May 2018 14:19:18 +0200, Stefan Agner wrote: > On 24.05.2018 13:53, Boris Brezillon wrote: > > Hi Benjamin, > >=20 > > On Thu, 24 May 2018 13:30:14 +0200 > > Benjamin Lindqvist wrote: > > =20 > >> Hi Stefan, > >> > >> It seems to me that a probe similar to what the BootROM does shouldn't > >> be awfully complicated to implement - just cycle through the switch > >> cases in case of an ECC error. But I guess that's more of an idea for > >> further improvements rather than a comment to the patch set under > >> review. =20 > >=20 > > Nope, not really an option, because you're not guaranteed that the NAND > > will be used as a boot media, and the first page or first set of pages > > might just be erased. > > =20 >=20 > Yeah I did not meant probing like the Boot ROM does. >=20 > What I meant was using only the ECC modes which are supported by the > Boot ROM when the driver tries to choose a viable mode. So that would > be: > - RS t=3D4 > - BCH t=3D8 > - BCH t=3D16 >=20 > Maybe we could add a property to enable that behavior: >=20 > tegra,use-bootable-ecc-only; I'm not sure a property is needed. As there is currently no official user of this driver, why not turning mandatory the nand-ecc-xxx properties? In the documentation you can add a note saying that using other algorithms than the three above is not supported by the BootROM. >=20 > >> > >> However, I think that allowing for an override of the oobsize > >> inference would be a good idea before merging, no? This could just be > >> a trivial #ifdef (at least temporarily). If you agree but don't feel > >> like doing it yourself, I'd be happy to pitch in. Let me know. =20 > >=20 > > That's why we have nand-ecc-xxx properties in the DT. > > =20 >=20 > Yes, nand-ecc-strength is the first thing I plan to implement, that way > strength can be defined in dt. >=20 > -- > Stefan Thanks, Miqu=C3=A8l