From mboxrd@z Thu Jan 1 00:00:00 1970 From: w.sang@pengutronix.de (Wolfram Sang) Date: Wed, 20 Jul 2011 10:51:42 +0200 Subject: [i.MX28 GPMI] problem overwriting all-0xff data in NAND In-Reply-To: <4E263AF2.60103@freescale.com> References: <20004.12663.29494.339601@ipc1.ka-ro> <20110718164354.GA3328@S2100-06.ap.freescale.net> <4E24E804.10002@freescale.com> <20005.7677.145955.789329@ipc1.ka-ro> <4E252C51.8070900@freescale.com> <20005.21635.427202.49313@ipc1.ka-ro> <4E263AF2.60103@freescale.com> Message-ID: <20110720085142.GA2377@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > >>>>>I am debugging the DMA bug now. and I will send it out when i fix it. > >>>>> > >>>>What sort of DMA bug? > >>>> > >>>The DMA may time-out. :( > >>> > >>>The DMA time-out may occur in two situations: > >>>[1] send a command DMA descriptor, see the nfc->send_command() function. > >>>[2] read the non-ecc data from nand, see the nfc->read_data() function. > >>> > >>>I don't know why. Maybe caused by the timing, or something else. > >I am confused. The send-command DMA timeout prevents any write for me. > >You guys surely would have noticed if you have been bitten as well. Does > >it depend on the NAND chip? > I think It does not depend on the NAND chip. > My test chip is Samsung K9G8G08U0M. > Sometimes, I can run a long time while there is no DMA timeout occurring; > Sometimes, the bug appears right away. For me, the bug always happens right away. So, if you need logs or debug output or can give me a pointer into some direction, I am glad to assist. -- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ | -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: Digital signature URL: