[casper] Reading ROACH2 FPGA BRAMs on PowerPC

[Danny Price]

Hi all

I'd like to read data from the FPGA on the ROACH2 powerpc, then pack it 
into UDP and send it out over Ethernet. Is there a straightforward and 
reasonably efficient way to read registers/bram from the FPGA on the 
ROACH2 powerpc? Better yet, has anyone implemented something already 
that they're happy to share? We need a ~0.5MB transfer, triggered when a 
register is incremented (once per second), so speed shouldn't be a major 
issue.

I know on the ROACH1 the BRAMs were available in /proc, and that the new 
tcpborphserver3 on the ROACH2 memory maps through the 'device nodes' in 
/dev/roach, but I'm not clear on how to read desired registers on the 
PPC though this...

Thanks
Danny