lhthanh wrote:

quoted

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.

  

quoted

Have I to write aother driver?
    

Yes.

  

quoted

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.

  

quoted

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.

  

Thank Scott and Timur very much! I will study more DMA driver and come 
back later. :)

Regard!