From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out.bhp.t-online.de ([195.145.119.39]) by pentafluge.infradead.org with esmtp (Exim 4.30 #5 (Red Hat Linux)) id 1B7VM5-0000xK-EP for linux-mtd@lists.infradead.org; Sun, 28 Mar 2004 09:09:17 +0100 Received: from ylva.bhp.t-online.de (ylva.ada.t-online.de [172.30.8.40]) by smtp-out.bhp.t-online.de (iPlanet Messaging Server 5.2 HotFix 1.17 (built Jun 23 2003)) with SMTP id <0HVA00CC31BFZ8@smtp-out.bhp.t-online.de> for linux-mtd@lists.infradead.org; Sun, 28 Mar 2004 10:09:16 +0200 (MEST) Date: Sun, 28 Mar 2004 09:05:51 +0100 From: Thomas Gleixner In-reply-to: <20040328075658.221981764D@desire.actrix.co.nz> To: manningc2@actrix.gen.nz, David Woodhouse , David Updegraff Message-id: <200403281005.51480.tglx@linutronix.de> MIME-version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7BIT Content-disposition: inline References: <406328A2.3060905@cray.com> <1080404311.17352.69.camel@imladris.demon.co.uk> <20040328075658.221981764D@desire.actrix.co.nz> cc: linux-mtd@lists.infradead.org Subject: Re: nand oob layout assumptions Reply-To: tglx@linutronix.de List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sunday 28 March 2004 10:06, Charles Manning wrote: > I agree with the idea of abstacting this as much as possible. Where the EEC > is stores (if indeed it even is stored in OOB) should not be the FS's > concern and should not be known to the FS. The FS should just be told that > the ECC passed, failed or fixed a single bit error. No problem with that > Unless we go for one abstract interface it will [continue to] be hell to > support more than one FS (it is already a /dev/ass/pain to try get YAFFS > and JFFS2 going on one machine due to different OOB layouts). The [already > bad] situation will only get worse when trying to deal with all the fun > that the newer NAND devices bring us. He ? I'm running YAFFS and JFFS2 since a long time on the same device and it works without any PITA. I just want to bring back into memories, that we had a long discussion about an abstract interface 2 years ago. There was no way to find a common solution as nobody was willing to break either JFFS2 or YAFFS1 or both. Again. I agree with the idea of an abstract interface as long as we keep the current stuff running. > No bitmask. That just passes mucky knowledge through the interface. > > Rather: > * Have the mtd tell the FS the number of unused bytes in the OOB. > * Pass a byte array through the interface and the mtd packs/unpacks this > around the ECC, bad block markers and other stuff. No objections. -- Thomas ________________________________________________________________________ linutronix - competence in embedded & realtime linux http://www.linutronix.de mail: tglx@linutronix.de