Hi Andrew

quoted

		spi-max-frequency = <50000000>;

That is a pretty high frequency. It is actually running at that speed?

I have not verified that we're actually hitting 50M.

Have you tried lower speed?

Sorry for being too brief about the things I've tested. But yes, I've
tested running at 15MHz with the same or similar enough results that
I've not been able to discern any difference.
Meaningful to mention here as well would be that I've tested with and
without DMA as well.

quoted

With this setup I'm getting a maximum throughput of about 90kB/s.
If I increase the chunk size / oa-cps to 64 I get a might higher
throughput ~900kB/s, but after 0-2s I get dump below (or similar).

Is this tcp traffic? Lost packets will have a big impact. You might
want to look at the link peer with tcpdump and look for retries. Also,
look if there are frames with bad checksums.

As you assume, this was with TCP. I'll do a run with tcpdump and see if
I can compile any intelligent statistics from that.