The "network coprocessors" are a bit lame imo. I initially tried to use them for packing, but they turned out to be very memory/cache bandwidth limited. They are also standard risk-v pretty much. I did run custom code on them though (and the Mediatek's "dsp" cores that are a bit more interesting extensions-wise, but are even more memory bw starved). There should be enough left in the tree to get one going pretty fast if one so wishes to play with those cores.