DMA

[mahdi hamzeh <mahdy.hamzeh@gmail.com>]

Hi,
I am working on a research project for which I should be able to
transfer data from memory to memory using DMA. I am working on a x86
machine but I want my code to be architecture independent as much as
possible. Please accept my apology if my question is too basic to be
asked from this mailing list. Here is my problem:
I used "struct dma_chan" to define a channel structure but when I use
"dma_request_channel" function to get a DMA channel, with all
different possible masks including DMA_MEMCPY, DMA_PRIVATE,....
anything, the function returns always NULL. This function is defined
in "dmaengine.h". I also tried a low level function to see dma channel
availability and "request_dma" function defined in "dma.h" works
perfect.
Any comment, help, document, program, reference anything that helps me
to create a simple DMA transaction would really be appreciated.
PS: There is a test program called dmatest.c is provided in the linux
kernel files. I tried to get it compiled but I could not since the
functions and structures used in this file has been changed in the
kernel header files.

Thanks
--
---Mahdi Hamzeh