Subject: Re: MPC8349E's DMA controller like ISA controller but with more feature?

From: Timur Tabi <[email-masked]>
Date: Fri, 24 Apr 2009 09:40:59 -0500

lhthanh wrote:

> 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 ?

No.

> Have I to write aother driver?

Yes.

> 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.

There is no framework for what you want to do.  There is only one other
driver that does what you want (sound/soc/fsl/fsl_dma.c), and that is a
complicated driver that does many things besides transferring data to an
I/O port.

> And I afraid that I can not write code which assure sharing DMA channels.

Look at arch/powerpc/boot/dts/mpc8610_hpcd.dts.  The DMA channels that
are needed by the 8610 audio driver have a different 'compatible'
property.  This is how you prevent the generic DMA driver from using a
channel that you want.

I'm afraid that you're going to have to study the DMA programming model,
and my device driver, and write a brand new driver from scratch.

-- 
Timur Tabi
Linux kernel developer at Freescale