I want to initiate a DMA-Transfer for testing.

I stumbled accross a dmatest.c in the kernel sources (drivers/dma). I compiled a Kernel with this Module and tried it without any params.

sudo modprobe dmatest

and i get with dmesg

__dma_request_channel: fail ((null))

What are the prerequisites for dmatest.ko? Should I load a special DMA-Engine? Is a special param for dmatest.ko required (default should probe anything!?)?

1 Answer

I think you can refer to for guide.

Certainly, you should run a DMA-Engine (module or built-in) before dmatest, there are a lot of DMA Controller driver under drivers/dma/, such as amba-pl08x.c, dw_dmac.c, pl330.c and so on.

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

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