cva6 VS litex

Hello. I'm looking into implementing RISC-V on an FPGA for a school project. The two repos I'm looking into using are the Ariane and RocketChip repos. Both look actively maintained, but RocketChip has more recent releases, and it's used by this other repo that creates a block design in Vivado with the RISC-V RTL. However, we would also like to be able to make changes to the core, and I'm afraid that scala/Chisel might be difficult to learn. Ariane looks like SystemVerilog while RocketChip is mostly Chisel. Does any have recommendations on which RISC-V repo would be good to use for a project?

There are 108 RISC-V cores that have been created so far (according to this list), but only a couple are 64 bit, open source and powerful enough that you would want to use them (like Shakti, CVA6 and NutShell)

The source code of Ara as well as Ariane, also known as CVA6 is available on GitHub.

I made a post about this here not too long ago, but I think it would be really useful to come up with a Vivado benchmark, in the form of a standardized large and representative design. I was curious about Alder Lake performance too, and compared my new 12700K workstation against my laptop with this open source RISC-V CPU: https://github.com/openhwgroup/cva6

When the OpenHW Group was created in 2019, I had some hope that Alibaba or NXP (who are in the OpenHW Group) would release an open hardware RISC-V processor, but it looks like they are not making any public commits to the CVA6 core, so I doubt that we are ever going to see the source code of Alibaba's XT910 or NXP's Chassis RISC-V processor.

Ariane is now cva6 (it moved to a industry supported non-profit).

At this stage, it could make sense for e.g. universities to start developing peripherals & controllers targeted at ASIC rather than creating yet-another-core (https://riscv.org/exchange/cores-socs/ has 107 lines already for cores), leveraging an OSHW ASIC-proven core from e.g. the OpenHW group (https://github.com/openhwgroup/cva6). Manufacturing in not-so-old processes is affordable for teaching institutions (e.g. https://europractice-ic.com/ in Europe), and taping out working cores is no longer a 'new' thing (e.g. http://asic.ethz.ch/all/years.html ).

Looking at the github of the openhw group looks like the license is granting patents to the project. So it looks ok.

https://github.com/enjoy-digital/litex

they have tutorials, you can get compatible boards for around $20

With LiteX you can synthesize a VexRiscV processor. You can run Linux on it. The toolchain is pretty easy to use, as long as you use Xilinx Vivado to compile to gateware.

LiteX is a great example of a Python-first flow. However, they have chosen not to subordinate the scripting environment to a GUI toolchain - EDA vendors are unlikely to choose the same trade.

To lean these: https://github.com/enjoy-digital/litex, https://github.com/m-labs/migen

If you use LiteX to generate a VexRiscV system-on-a-chip, you can include an open source DDR DRAM PHY. This works on Xilinx Spartan-6, Spartan7Artix7/Kintex7/Virtex7 FPGAs, and Lattice ECP5 FPGAs. DDR/LPDDR/DDR2/DDR3 depending on the FPGA.

I am interested in trying out FPGAs for the purpose of running specific calculations more efficiently. Since the calculations themselves are quite complex, I would need to be able to program in a relatively high-level language. I've seen that designing SoC in Python is possible, for example with Litex (https://github.com/enjoy-digital/litex) or Amaranth (https://github.com/amaranth-lang/). I don't want to spend hundreds of hours learning about FPGAs, but I'm prepared to take on a challenge.