Re: MPC85xx DMA support for Kernel 2.6?

On Jun 30, 2005, at 10:12 AM, Clemens Koller wrote:

Hello!

I am planning to use DMA/burst access for copying large chunks of data
(100MBytes) from the Local Bus (UPM accessed SRAM) to System Memory  
(DDR)
as fast as possible (200MBytes/s). (As you can guess, that's a  
framegrabber).

As far as I have seen, the DMA engines of the MPC85xx (fsl-dma) are  
not
supported in the classical way (dma_request(), free_dma()) in the  
kernel 2.6.x.
The memory allocators in arch/ppc/dma-mapping.c seem to be usable,
but there is no valuable dma support yet (true?).

I can program the DMA Controllers in my MPC8540 on my own to  
achieve what I want
but it would be great to get/produce/stick with as much cross- 
platform reusable
code as possible.

Is there any ongoing work to put DMA support for the mpc85xx and  
similar
devices into the kernel? Is there any ongoing work in this area
or is somebody working with the fsl-dma and can publish some code and
share some ideas?

I'm not aware of anyone work on such a thing.  I'd be more than happy  
to accept patches for it.  I know several of us have written some  
APIs on top of the DMA for 85xx.  Those however are non-standard APIs.

What APIs exist for general purpose DMA engines?  Last time I looked  
at this problem nothing really existed.

- kumar