Take data from a DMA region and write it to a file in linux?

Question

Essentially what I have is a region of reserved memory in DDR that Im DMAing stuff into. What I want to do is take that data in the DMA region and write it to a file for use with other linux commands. Is that a possible thing to do? If so, is there a command to do it, or a driver that can do it? This is using the Petalinux Yocto kernel

I tried just doing a cp from that region within from proc/device-tree/reserved-memory into the file of choice, but I surmised that would not work.

Answer 1

You'll need to mmap() the memory to have it accessible in userspace. Take a look here for more info: https://support.xilinx.com/s/question/0D52E00006hpLPrSAM/mmap-to-reserved-memory-using-huge-page?language=en_US