From: Scott Wood <scottwood@freescale.com>
To: raul.moreno@telvent.abengoa.com
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: DMA problem - mpc8xx
Date: Tue, 23 Oct 2007 13:49:35 -0500 [thread overview]
Message-ID: <471E423F.40304@freescale.com> (raw)
In-Reply-To: <OF0ED90B65.60296006-ONC125737D.0028DB92-C125737D.002A55F3@abengoa.com>
raul.moreno@telvent.abengoa.com wrote:
> Hi everybody,
>
> I am having problems with the serial cpm driver in a mpc866. But I've found
> out that my problem comes from the DMA and not really from the driver. The
> Rx and Tx buffers use the DMA and then the sytem hangs. However, if I set
> these buffers to internal ram memory (DPRAM), it works. The DMA address is
> configured with a kernel parameter in advance setup:
> CONFIG_CONSISTENT_START (and the size in CONFIG_CONSISTENT_SIZE), but I
> don't know what they are exactly and I could not find a right documentation
> about it.
> I saw a pair of mailing list where some guys set the
> CONFIG_CONSISTENT_START to 0xff100000, but my driver continues failing (and
> an error about dma-mapping appears in the boot).
What kernel version? arch/ppc or arch/powerpc? What is the error about
dma-mapping that you get? What does your memory map look like (in
particular, is there anything that might be getting mapped in conflict
with the consistent area at 0xff100000)?
-Scott
prev parent reply other threads:[~2007-10-23 18:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-13 14:05 Informations about mem and proc environment between bootloader and kernel fabien boucher
2007-09-13 14:23 ` raul.moreno
2007-09-14 19:57 ` Wolfgang Denk
2007-10-23 7:42 ` DMA problem - mpc8xx raul.moreno
2007-10-23 18:49 ` Scott Wood [this message]
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