From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eu1sys200aog105.obsmtp.com ([207.126.144.119]) by canuck.infradead.org with smtps (Exim 4.76 #1 (Red Hat Linux)) id 1RGY1Q-0006a2-T9 for linux-mtd@lists.infradead.org; Wed, 19 Oct 2011 15:25:38 +0000 Message-ID: <4E9EEBDC.5000002@st.com> Date: Wed, 19 Oct 2011 16:25:16 +0100 From: Angus CLARK MIME-Version: 1.0 To: "Kumar, Goutam" Subject: Re: ubifs not working with 3.1 kernel and MT29F2G08ABAEAWP NAND Flash. References: <0680EC522D0CC943BC586913CF3768C0059050481E@dbde02.ent.ti.com> In-Reply-To: <0680EC522D0CC943BC586913CF3768C0059050481E@dbde02.ent.ti.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "linux-mtd@lists.infradead.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Goutam, On 10/19/2011 03:28 PM, Kumar, Goutam wrote: > > There is MT29F2G08ABAEAWP (256MB, 8-bit) NAND device on TI EVM. > This particular NAND device requires 4-bit ECC. As far as I can tell, you are using the OMAP2 driver with 1-bit Hamming H/W ECC. This will throw uncorrectable ECC errors (as seen in your log) if there are 2 bit flips in any ECC block. The problem gets worse if there are 3 or 4 bit flips, which is still within spec of the NAND device. This may, or may not, be the source of your problem, but it might be worth taking a look anyway. The device does include a 4-bit on-die ECC engine, which can be enabled using the 'SET_FEATURE' command. I don't believe this is available in nand_base.c at present, but it is not too hard to add. You would also need to disable the OMAP2 H/W ECC support to avoid any layout clashes in the OOB area. Of course, whatever changes you make to the kernel, would also have to be made to u-boot. Cheers, Angus