Dmatest.ko - how to use it?

Question

I want to initiate DMA-Transfer for testing.

I came across dmatest.c in kernel sources (drivers / dma). I compiled the kernel with this module and tried it without any parameters.

sudo modprobe dmatest 

and I get with dmesg

 __dma_request_channel: fail ((null)) 

What are the prerequisites for dmatest.ko? Should I download a special DMA engine? Is this a special parameter for dmatest.ko required (should the default check something !?)?

Answer 1

I think you can refer to https://www.kernel.org/doc/Documentation/dmatest.txt for guidance.

Of course, you have to start the DMA-Engine (module or built-in) to the most difficult, there are many DMA Controller drivers in the / dma drivers, such as amba-pl08x.c, dw_dmac.c, pl330. c etc.

You can use the command "ls -1 / sys / class / dma /" to print the available channel lists.