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RISC-V in the loop

Continuous integration (‘CI’) for hardware is a logical step to take: Why not do for hardware, what works fine for software?

To keep things short: I’ve decided to stick my proprietary RISC-V approach ‘pyrv32’ into the opensourced MaSoCist testing loop to always have an online reference that can run anywhere without massive software installation dances.

Because there’s still quite a part of the toolchain missing from the OpenSource repo (work in progress), only a stripped down VHDL edition of the pyrv32 is available for testing and playing around.

This is what it currently does, when running ‘make all test’ in the provided Docker environment:

  • Build some tools necessary to build the virtual hardware
  • Compile source code, create a ROM file from it as VHDL
  • Build a virtual System on Chip based on the pyrv32 core
  • Downloads the ‘official’ riscv-tests suite onto the virtual target and runs the tests
  • Optionally, you can also talk to the system via a virtual (UART) console

Instructions

This is the quickest ‘online’ way without installing software. You might need to register yourself a docker account beforehand.

  1. Log in at the docker playground: https://labs.play-with-docker.com
  2. Add a new instance of a virtual machine via the left panel
  3. Run the docker container:
    docker run -it hackfin/masocist
  4. Run the test suite:
    wget section5.ch/downloads/masocist_sfx.sh && sh masocist_sfx.sh && make all test
  5. Likewise, you can run the virtual console demo:
    make clean run-pyrv32
  6. Wait for Boot message and # prompt to appear, then type h for help.
  7. Dump virtual SPI flash:
    s 0 1
  8. Exit minicom terminal by Ctrl-A, then q.

What’s in the box?

  • ghdl, ghdlex: Turns a set of VHDL sources into a simulation executable that exposes signals to the network (The engine for the virtual chip).
  • masocist: A build system for a System on Chip:
    • GNU Make, Linux kconfig
    • Plenty of XML hardware definitions based on netpp.
    • IP core library and plenty of ugly preprocessor hacks
    • Cross compiler packages for ZPU, riscv32 and msp430 architectures
  • gensoc: SoC generator alias IP-XACT’s mean little brother (from another mother…)
  • In-House CPU cores with In Circuit Emulation features (Debug TAPs over JTAG, etc.):
    • ZPUng: pipelined ZPU architecture with optimum code density
    • pyrv32: a rv32ui compatible RISC-V core
  • Third party opensource cores, not fully verified (but running a simple I/O test):
    • neo430: a msp430 compatible architecture in VHDL
    • potato: a RISC-V compatible CPU design