From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf0-x241.google.com ([2607:f8b0:400e:c00::241]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1bBYTh-0008RN-Bj for linux-mtd@lists.infradead.org; Sat, 11 Jun 2016 02:16:50 +0000 Received: by mail-pf0-x241.google.com with SMTP id 66so4254509pfy.1 for ; Fri, 10 Jun 2016 19:16:28 -0700 (PDT) Date: Fri, 10 Jun 2016 19:16:25 -0700 From: Brian Norris To: Boris Brezillon Cc: Richard Weinberger , linux-mtd@lists.infradead.org, David Woodhouse , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/4] mtd: add support for pairing scheme description Message-ID: <20160611021625.GA144502@google.com> References: <1461578481-26567-1-git-send-email-boris.brezillon@free-electrons.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1461578481-26567-1-git-send-email-boris.brezillon@free-electrons.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Boris, I've mostly just reviewed the cover and first patch for now, since that sets up the rest. A few questions and comments. I hope to review some more and have more to say later this weekend. On Mon, Apr 25, 2016 at 12:01:17PM +0200, Boris Brezillon wrote: > Hi, > > This series is the first step towards reliable MLC/TLC NAND support. > Those patches allows the NAND layer to expose page pairing information > to MTD users. Have you surveyed many types of NAND to get a representative sampling of what kind of pairing schemes are out there? Do you think you've covered the possibilities well enough in your API? I have a few comments on the patches to this effect. I honestly don't know the answer to these questions, because AFAIR, this is rarely well documented in datasheets. > The plan is to teach UBI about those constraints and let UBI code take > the appropriate precautions when dealing with those multi-level cells > NANDs. The way we'll handle this "paired pages" constraint will be > described soon in a series adapting the UBI layer, so stay tune ;). > > Note that this implementation only allows page pairing scheme description > when the NAND has a full-id entry in the nand_ids table. > This should be addressed in some way for ONFI and JEDEC NANDs, though > I'm not sure how to handle this yet. Do ONFI or JEDEC parameter pages even provide this kind of info? The ONFI spec doesn't mention paired pages. Brian > Best Regards, > > Boris > > Boris Brezillon (4): > mtd: introduce the mtd_pairing_scheme concept > mtd: nand: implement two pairing scheme > mtd: nand: add a pairing field to nand_flash_dev > mtd: nand: H27UCG8T2ATR: point to the correct pairing scheme > implementation > > drivers/mtd/mtdcore.c | 62 ++++++++++++++++++++++++++++ > drivers/mtd/mtdpart.c | 1 + > drivers/mtd/nand/nand_base.c | 97 ++++++++++++++++++++++++++++++++++++++++++++ > drivers/mtd/nand/nand_ids.c | 2 +- > include/linux/mtd/mtd.h | 64 +++++++++++++++++++++++++++++ > include/linux/mtd/nand.h | 5 +++ > 6 files changed, 230 insertions(+), 1 deletion(-) > > -- > 2.7.4 >