Linux on Open Source Hardware with RISC-V

Want to run Linux on open hardware? This talk will explore Open Source Hardware projects capable of that task, and explore how RISC-V and free software FPGA projects can be leveraged to create libre systems.

This talk will explore Open Source Hardware projects relevant to Linux, including boards like BeagleBone, Olimex OLinuXino, the Reform laptop and more.

I will also talk about the importance of the open RISC-V instruction set and free software FPGA toolchains. I will explain how myself and others at Hackaday Supercon teamed up to get Linux running on RISC-V core in the ECP5 FPGA badge. I will explain what LiteX is and how it enabled us to quickly build a SoC capable of running Linux.

Finally, I will explore the landscape of open source chip design projects and the Linux-capable RISC-V silicon chips on horizon for 2020.

Notes

• https://github.com/pdp7/talks
• https://github.com/pdp7/talks/blob/master/rv-elc.pdf
• https://media.ccc.de/v/36c3-10549-linux_on_open_source_hardware_with_open_source_chip_design

What’s required to be “open hardware”

• schematic
• board layouts

RISC V: The instruction set for everything?

• ISA=instruction set architecture
• ARM requires commercial licening

What’s different about RISC-V

• simple
• clean slate design
• modular
  • extensively/specialization
  • small standards base ISA, with multiple standard extensions
• stable
• community design

Ecosystem

• opensource software
• commercial software
• open-source cores

Hardware

• commercial cores
• commercial core provisders
• inhouse cores

Industry

• Most people are just licensing cores from ARM
• open source implementation
  • BOOM, Rocket, PULP, SweRV

Chips

lowRISC

• not-for-profit organisation
• OpenTitan project with Google

SiFive

• SiFive FE310 microcontroller
• HiFive1: Arguino Compatible RISC-V dev kit

Linux on RISV-V

• HiFive Unleashed
  • best core if you want to run RISC-V Linux
  • mostly just a proof of concept

Kendryte K210

• 8 mb of SRAM
• $13
• https://hackaday.com/2019/02/14/new-part-day-a-risc-v-cpu-for-eight-dollars/
• Has MMU but too old to be supported by linux
• will be suported in Linux 5.8

PolarFire

• CORE-V Chassis - tapeout 2H 2020
• Hard RISC-V with FPGA fabric

Open Source FPGA Tools

• MeganWachs - Keynote RISC-V and FPGAs: Open Source Hardware Hacking
• Lattice

Linux on Badge

• has ECP5 FPGA
  • Supported by open source FPGA tool
• Linux running on Supercon badge
• 2019 Supercon badget
• 32 MB of SDRAM to the Hackaday badge

Migen

• HDL written in python
• https://github.com/litex-hub/fpga_101

LiteX

• Litex used to build cores, create SoCs and full FPGA designs
• LiteX Hub - Collaborative FPGA projects around LiteX
• Based on Migen

Linux on LiteX

• https://github.com/litex-hub/linux-on-litex-vexriscv

What baords could you use?

• ULX3S
  • ECP FPGA dev board

Quickstart - FPGA

• Fomu
  • RGB LED
  • MicroPython
  • Verilog
  • LiteX

Quickstart -No Hardware

• Renode