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From: Clemens Koller <clemens.koller@anagramm.de>
To: Dan Malek <dan@embeddededge.com>
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: MPC85xx DMA support for Kernel 2.6?
Date: Fri, 01 Jul 2005 09:47:25 +0200	[thread overview]
Message-ID: <42C4F50D.3050405@anagramm.de> (raw)
In-Reply-To: <427c70958bb995dad4fbad2e6ff121bc@embeddededge.com>

Hi, Dan!

Dan Malek wrote:
> Before you start, just make sure such a thing is really a performance
> enhancement.  Yes, the DMA does run in parallel with the core, but often
> the overhead of the set up and clean up interrupt is more code and time
> that if you just copied the data in a loop.  If possible, integrate the DMA
> processing into other driver work, clean up a previous DMA the next time
> the driver needs to use it, not with a separate completion handler.

Well... thanks. But the CPU is intended to do image processing while
data comes in. And currently, when I access (memcopy) the SRAM on my
Local Bus via UPM I cannot get it to generate bursts yet, so I hope the
DMA will speed up those things, too.

Greets,

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
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http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19

  reply	other threads:[~2005-07-01  7:47 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-06-30 15:12 MPC85xx DMA support for Kernel 2.6? Clemens Koller
2005-06-30 15:30 ` Kumar Gala
2005-06-30 15:56   ` Clemens Koller
2005-06-30 16:57     ` Murray.Jensen
2005-07-01  7:54       ` Clemens Koller
2005-07-01  8:36         ` Murray.Jensen
2005-07-01 13:59           ` Kumar Gala
2005-06-30 18:52     ` Dan Malek
2005-07-01  7:47       ` Clemens Koller [this message]
2005-07-01 14:02         ` Dan Malek
2005-07-01 14:15           ` Mark Chambers
2005-07-01 21:49             ` Dan Malek
2005-07-04  9:03               ` Clemens Koller

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