[Libre-soc-dev] arctic tern twin FPGA modules into talos2 server

[Timothy Pearson]

If anyone's curious just what Arctic Tern is, here's one plugged into a Blackbird system on my desk:
https://wiki.raptorcs.com/wiki/File:Tpearson_arctic_tern_blackbird_bmc.png

The ASpeed is completely bypassed here, Kestrel (running on Arctic Tern) is doing all the work.  The second module isn't even configured, the base Kestrel system fits quite comfortably on the first module alone.

We're still finishing up documentation etc., but the initial Kestrel port is here:

https://gitlab.raptorengineering.com/kestrel-collaboration/kestrel-litex/litex-boards
https://gitlab.raptorengineering.com/kestrel-collaboration/kestrel-firmware/bare-metal-firmware

For the curious, the ribbon cable running off to the right is RS-232 serial (same pinout and electrical configuration as the Talos II / Blackbird mainboards).  The CPU fan is plugged directly into the carrier card, and the alphanumeric display is showing the BMC status code (single character on the left) and the last seen system IPL POST code (three characters on the right).  It is plugged into a PCIe slot, and the electrical wiring exists to bring the PCIe link up, but is currently only pulling power from the slot since (at least right now) there is no open source HDL to implement a PCIe slave core.

On the left, you have gigabit Ethernet and one mini HDMI port for each module (IT6612 transceivers, same as the Blackbird).  Each module has 1GB (yes, gigabyte) of DDR3 RAM onboard.