From: lhthanh <lhthanh@kobekara•com>
To: Timur Tabi <timur@freescale•com>
Cc: Scott Wood <scottwood@freescale•com>, linuxppc-dev@ozlabs•org
Subject: Re: MPC8349E's DMA controller like ISA controller but with more feature?
Date: Fri, 24 Apr 2009 13:12:01 +0700 [thread overview]
Message-ID: <49F15831.9080507@kobekara.com> (raw)
In-Reply-To: <49F08FBC.9010903@freescale.com>
Thank Scott and Timur!
> Scott Wood wrote:
>
>> Timur Tabi (CCed) has written an audio
>> driver that does something very similar; he could probably tell you more
>> about how to do that (this is why such discussions should be kept on the
>> mailing list rather than taken to private e-mail).
>>
>
> The code in drivers/dma cannot be used to send a buffer of data to a
> single I/O port. That code is just an elaborate version of memcpy that
> uses the DMA engine to copy data in the background.
>
>
Thanks for your explaination! So if I want to transfer a buffer of data
from a single I/O port, will not DMA framework
also be able ? Have I to write aother driver?
> If you want to transfer a buffer to a single I/O port, you will need to
> write your own DMA driver, similar to what I've done in
> sound/soc/fsl/fsl_dma.c. This is not trivial. You will need to
> understand the DMA hardware programming model to determine whether you
> can use direct mode or if you need to create link descriptors.
>
>
Actually, I don't want write all because there are serveral DMA code at
hand. I only want to use a framework instead of re-writing.
And I afraid that I can not write code which assure sharing DMA channels.
Regards!
next prev parent reply other threads:[~2009-04-24 6:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-20 12:38 MPC8349E's DMA controller like ISA controller but with more feature? lhthanh
2009-04-20 15:55 ` Scott Wood
2009-04-20 17:23 ` Timur Tabi
[not found] ` <49EFEA26.2010602@kobekara.com>
[not found] ` <20090423154311.GA19717@ld0162-tx32.am.freescale.net>
[not found] ` <49F08FBC.9010903@freescale.com>
2009-04-24 6:12 ` lhthanh [this message]
2009-04-24 14:40 ` Timur Tabi
2009-05-07 1:59 ` lhthanh
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