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Date: Tue, 19 Jul 2011 15:36:02 +0200
From: Wolfram Sang <w.sang@pengutronix.de>
To: Lothar =?iso-8859-15?Q?Wa=DFmann?= <LW@KARO-electronics.de>
Subject: Re: [i.MX28 GPMI] problem overwriting all-0xff data in NAND
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Cc: Huang Shijie <b32955@freescale.com>, linux-mtd@lists.infradead.org,
	Shawn Guo <shawn.guo@freescale.com>, linux-arm-kernel@lists.infradead.org
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> > >> I am debugging the DMA bug now. and I will send it out when i fix it.
> > >>
> > > What sort of DMA bug?
> > >
> >=20
> > The DMA may time-out. :(
> >=20
> > 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.
> >=20
> > 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?

> Maybe you are missing this patch:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2011-April/049105.h=
tml
> I sent it in April, but apparently it has not been integrated in
> mainline or the pengutronix git.

Well, just resend them; might be worth trying Shawn's comment, too (if
that reset is really needed). BTW they didn't help for my case :(

Regards,

   Wolfram

--=20
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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