From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mexforward.lss.emc.com ([128.222.32.20]) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1NLMgl-0003js-GG for linux-mtd@lists.infradead.org; Thu, 17 Dec 2009 20:11:11 +0000 Received: from hop04-l1d11-si03.isus.emc.com (HOP04-L1D11-SI03.isus.emc.com [10.254.111.23]) by mexforward.lss.emc.com (Switch-3.3.2/Switch-3.1.7) with ESMTP id nBHKB66w013543 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 17 Dec 2009 15:11:06 -0500 Received: from mailhub.lss.emc.com (nagas.lss.emc.com [10.254.144.15]) by hop04-l1d11-si03.isus.emc.com (RSA Interceptor) for ; Thu, 17 Dec 2009 15:10:55 -0500 Received: from mailhub2.iomegacorp.com (mailhub.iomegacorp.com [147.178.68.20]) by mailhub.lss.emc.com (Switch-3.4.2/Switch-3.3.2mp) with ESMTP id nBHKAs2Z015297 for ; Thu, 17 Dec 2009 15:10:55 -0500 Received: from EXCAS01.iomegacorp.com (excas01.iomegacorp.com [147.178.90.117]) by mailhub2.iomegacorp.com (Postfix) with ESMTP id AB5B3200E1 for ; Thu, 17 Dec 2009 20:10:54 +0000 (UTC) Message-ID: <4B2A920A.5080808@iomega.com> Date: Thu, 17 Dec 2009 13:18:18 -0700 From: Dennis Millard MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Subject: 4bit NAND ECC Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Anyone who has worked with NAND ECC support, I have a question- I have a platform running the 2.6.30 kernel based on the Marvell 88F6281. It has 512 MB NAND flash, and is very similar to the Marvell Sheevaplug reference design. My Uboot is using 4bit NAND ECC to write the kernel and ramdisk to flash. However, I recently discovered that the 2.6.30 kernel does not support 4bit ECC mode. When I try to access the Uboot environment variables from the running kernel, I can only use 1bit ECC. When I switch Uboot to use 1bit ECC, I get lots of errors while accessing the Uboot vars in flash. I've been told that I really should be using 4bit ECC in Uboot. I noticed that the 2.6.32 kernel supports 4bit ECC, but it appears to be only for the TI DaVinci CPU. Can someone confirm this? Does this mean that 4bit ECC is not available for general use in the 2.6.32 kernel? Does anyone know of a patch that would make it available for the Marvell 88F6281? Thanks- Dennis Millard