From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by canuck.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QjSVS-0006tf-4I for linux-mtd@lists.infradead.org; Wed, 20 Jul 2011 08:51:55 +0000 Date: Wed, 20 Jul 2011 10:51:42 +0200 From: Wolfram Sang To: Huang Shijie Subject: Re: [i.MX28 GPMI] problem overwriting all-0xff data in NAND Message-ID: <20110720085142.GA2377@pengutronix.de> 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> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="0OAP2g/MAC+5xKAE" Content-Disposition: inline In-Reply-To: <4E263AF2.60103@freescale.com> Cc: linux-mtd@lists.infradead.org, Shawn Guo , linux-arm-kernel@lists.infradead.org, Lothar =?iso-8859-15?Q?Wa=DFmann?= List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --0OAP2g/MAC+5xKAE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > >>>>>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() functio= n. > >>>[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. --=20 Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ | --0OAP2g/MAC+5xKAE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAk4mlx4ACgkQD27XaX1/VRsavQCbBlB1WQ8zdVEfYv7oF5NkNG6k y0UAnil8V+5dAnrNfJv1qGuf4pJc5WE6 =HOum -----END PGP SIGNATURE----- --0OAP2g/MAC+5xKAE--