From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pd9e41c87.dip.t-dialin.net ([217.228.28.135] helo=thomas.tec.autronix.de) by pentafluge.infradead.org with esmtp (Exim 3.22 #1 (Red Hat Linux)) id 16ckBw-0002nT-00 for ; Mon, 18 Feb 2002 09:34:36 +0000 Content-Type: text/plain; charset="iso-8859-1" From: Thomas Gleixner Reply-To: gleixner@autronix.de To: David Woodhouse , gleixner@autronix.de Subject: Re: JFFS2 & NAND Date: Mon, 18 Feb 2002 10:48:33 +0100 Cc: linux-mtd@lists.infradead.org, jffs-dev@axis.com References: <02021810263602.00860@thomas> <11512.1014021987@redhat.com> <19529.1014024551@redhat.com> In-Reply-To: <19529.1014024551@redhat.com> MIME-Version: 1.0 Message-Id: <02021810483303.00860@thomas> Content-Transfer-Encoding: 8bit Sender: linux-mtd-admin@lists.infradead.org Errors-To: linux-mtd-admin@lists.infradead.org List-Help: List-Post: List-Subscribe: , List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: On Monday, 18. February 2002 10:29, David Woodhouse wrote: > gleixner@autronix.de said: > > Yes inside JFFS2, but who tells the NAND driver, which layout to use. > > Do we really need the NAND driver to be able to use more than one layout? > > Either we have hardware ECC which determines the layout, or the NAND driver > implements software ECC and gets to choose. Can't the filesystem just deal > with the ECC layout used by the NAND driver, as determined by the > underlying hardware? Also hardware ECC does not determine the layout. It just builds the ECC, you have to read it out of the CLPD and write it at a appropriate place in the OOB area. Same on read. We can use a fixed layout for every chip-type. There are 2 good reasons not to do that. 1. The SMC DOS-FAT oob layout is more than ugly. To press our idea of oob usage into this, is like you slice a bread in many small pieces to fit into the subdivisions of your tupperbox, instead of rearanging the contents of the box. 2. I don't want to put too much restrictions into the oob layout, so we would make it hard for somebody, who want's to implement a different filesystem than JFFS2. -- Thomas __________________________________________________ Thomas Gleixner, autronix automation GmbH auf dem berg 3, d-88690 uhldingen-muehlhofen fon: +49 7556 919891 , fax: +49 7556 919886 mail: gleixner@autronix.de, http://www.autronix.de