From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail1.cray.com ([136.162.0.111]) by pentafluge.infradead.org with esmtp (Exim 4.30 #5 (Red Hat Linux)) id 1B6Zqf-0003XE-4I for linux-mtd@lists.infradead.org; Thu, 25 Mar 2004 18:45:01 +0000 Received: from relaya.us.cray.com (relaya.us.cray.com [192.168.252.144]) i2PIirFj007005 for ; Thu, 25 Mar 2004 12:44:54 -0600 (CST) Received: from orchid.us.cray.com (orchid.us.cray.com [172.30.27.91]) i2PIiqUc011821 for ; Thu, 25 Mar 2004 12:44:52 -0600 (CST) Received: from cray.com (troll [192.168.250.5])i2PIipTi4454784 for ; Thu, 25 Mar 2004 12:44:52 -0600 (CST) Message-ID: <406328A2.3060905@cray.com> Date: Thu, 25 Mar 2004 12:44:50 -0600 From: David Updegraff MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Subject: nand oob layout assumptions List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi. So I have a little ducttape-string-and-bailing wire driver here now that deals with these newer bigger Samsung K9xxx chips; am hitting snags around the declarations of oob areas. The ecc calcluations within the driver are easy to deal with, straightup algorithm of ecc-space-needed = 3 * #-of-256byte chunks in the page. But how to cope with that exposed oobinfo structure defn. in mtd.h that declares the all the universe uses 6 bytes for ecc in oob? It seems we need the lo-level driver to declare (and allocate?) that oobinfo struct, and while we're at breaking everything by doing so, add a badblock_pos element to it, since these samsung chips mark badblocks not at offset:5 but offset:0 in oob. I have no solution dreamed up yet on how to cope with the MEMSETOOBSEL ioctl, though. Do you? -dbu.