From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4E24E804.10002@freescale.com> Date: Tue, 19 Jul 2011 10:12:20 +0800 From: Huang Shijie MIME-Version: 1.0 To: Shawn Guo Subject: Re: [i.MX28 GPMI] problem overwriting all-0xff data in NAND References: <20004.12663.29494.339601@ipc1.ka-ro> <20110718164354.GA3328@S2100-06.ap.freescale.net> In-Reply-To: <20110718164354.GA3328@S2100-06.ap.freescale.net> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: quoted-printable Cc: linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, =?ISO-8859-1?Q?Lothar_Wa=DFmann?= List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , hi Lothar: > On Mon, Jul 18, 2011 at 03:13:27PM +0200, Lothar Wa=DFmann wrote: >> Hi, >> >> with the gpmi-nfc driver for imx28 from Shawn Guo on a TX28 I > To be clear, the author of gpmi-nfc driver is Huang Shijie (Cc-ed). > > Regards, > Shawn > >> encountered some problems with jffs2 when overwriting pages that have >> been written with 0xff (e.g. from padding from the file system image >> file). The GPMI driver now does not support the JFFS2 very well. The JFFS2 will write the OOB, while the BCH of GPMI will use the OOB too. So I have to disable the JFFS2 to use the OOB. I have not finish the=20 code about it now. I recommend you use the UBIFS. But the latest version of GPMI driver=20 meets a DMA bug. I am debugging the DMA bug now. and I will send it out when i fix it. Best Regards Huang Shijie >> The problem is that the ECC info for an all-0xff block is not all-0xff >> and thus a newly erased block is different from a block that has been >> written with 0xff. >> If such a block is being altered (jffs2 thinking it can simply >> overwrite it without erasing first) the ECC information will be >> corrupted and will produce ECC errors upon read. >> >> The only remedy I can think of is to prevent empty pages from actually >> being written to flash, but leaving them in the erased state instead. >> >> Any comments? >> >> >> Lothar Wa=DFmann >> --=20 >> ___________________________________________________________ >> >> Ka-Ro electronics GmbH | Pascalstra=DFe 22 | D - 52076 Aachen >> Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 >> Gesch=E4ftsf=FChrer: Matthias Kaussen >> Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 >> >> www.karo-electronics.de | info@karo-electronics.de >> ___________________________________________________________ >>