Using DMA Controller in a Linux Driver

A nice hello to everyone,

i need some advice.

I wrote a driver which works very fine so far. But i need to do some dma operations to move data.

The question is, how to initialize it?

Of course in a driver, the very first step is to ask the kernel for this ressource by something

like this in your driver code:

ret= request_dma(0,"mydriver")

But it fails. Error code -22 -> -EINVAL

For sure i have a dma controller. I can "see" it in the proc directory of my linux.

In addition i looked up the sources dma.h and dma.c, to figure out how it works. I have found some special functions concerning setting the parameter .

Maybe someone has an idea or an example (copy memory from one location to another location).

Thanks a lot.