Opentitan on FPGA

[gtelzur]

I am interested in implementing Opentitan on a cheap FPGA. The reference board, CW310, is very expensive.
Can cheap FPGAs such as Tang nano 9k, ICE40, ECP5, etc' be used? My preference is to use open-source tools as much as possible. Perhaps these FPGAs don't have enough resources for the whole Opentitan and only a partial implementation is possible!?
I would appreciate any comments/recommendations.

[kgf]

Hello, 

Open Titan is a larger research project (visit https://docs.opentitan.org/ for more information). People in these projects try to use capable boards so that they have enough resources just in case, the development requires a bit more effort. 

Are you interested in root of trust system or a generic RISC-V system (since you mention stripping things away). Maybe the Litex (https://github.com/enjoy-digital/litex) project is a better entry to get started. AFAIK they also support several PULP cores (or at least Ariane).. 

BTW, if you have any ports of our existing systems to one of the FPGA boards you mention, please send a merge request.. we will be happy to include it. 

Generally, the problem is that we did not target a specific compiler, simulator toolchain for our project and different components have slightly different requirements. Some (most) of the open source tools support a subset of the language features and therefore sometimes it is tricky to use open source tools. However, we are trying to clean up things (slowly) and the open source tools are getting better at supporting additional features, so the gap will close sooner than later. But at the moment, depending on what you want to use, there could be compatibility issues. 

Litex I think is a good choice, as it allows you to mix and match code from different projects and it manages the tool diversity internally. Just a suggestion.. 

Cheers, 
KGF

[gtelzur]

Thanks a lot for the reply.
I will check the litex project. My current goal is to try to implement at least some security features on the FPGA, not the whole Opentitan offering.

Regards,

Guy