2020 Jun FSic2020 Eth Zurich, Switzerland


2020 Jun OpenPOWER Summit North America.

25 and 26 June we'll be in lovely Austin, TX, the same week and venue as the Linux Foundation's Open Source Summit.

To keep an eye on:

XDC 2020

OpenPOWER 2020

SFSCON 2020, italy

Why a Libre 3D CPU / GPU / VPU?

  • Study of SoCs (Allwinner, Rockchip, NXP) shows none are fully Libre
    • Either GPU driver firmware is proprietary, or VPU firmware, or bootloader
  • This causes customer product development issues
    • https://tinyurl.com/valve-steam-intel
  • Businesses are waking up to lack of transparency
    • Intel Management Engine (spying backdoor co-processor)
    • Spectre, Meltdown, CSME (Chain-of-Trust) issues
  • Solution: full transparency. All source available for everything.

How is LibreSOC being developed?

  • Using Libre (rather than "open") development practices
    • no "I'll release it when it's ready": all development is real-time public access
  • No NDAs, no hidden discussions
    • we can invite anyone (any expert) to help with review
    • free to ask for help anywhere in the world (comp.arch, stackexchange)
  • Using litex, nmigen, opencores HDL
    • heavily depending on python OO (not possible with VHDL or Verilog)
    • leap-frogging ahead by not reinventing the wheel
    • yosys converts nmigen to verilog for standard tools.

Why is it different from other SoCs?

  • LibreSOC is a hybrid CPU-VPU-GPU architecture.
    • OpenPOWER ISA itself is extended to include 3D and Video instructions
    • (SIN, ATAN2, YUV2RGB, Texture Interpolation)
    • Only after approval of OpenPOWER Foundation!
    • There is no separate GPU or VPU: it really is the same core.
    • Massively simplifies driver development and application debugging
  • Vectorisation is "Simple-V" (VSX not being implemented)
    • VSX is SIMD and is considered harmful
    • https://www.sigarch.org/simd-instructions-considered-harmful/

What is being developed? (Roadmap)

  • First simple core achieved in simulation Sep 2020
    • FPGA (ECP5) target followed shortly
  • First silicon tape-out 180nm deadline 2nd Dec 2020
    • sponsored by NLnet, with help from Chips4Makers Libre Cell Libraries
    • layout is entirely libre-licensed tools: coriolis2 from lip6.fr
  • Next chip is "SBC" style quad-core
    • similar spec to Allwinner A64, Rockchip RK3399
    • targets "Pi" boards, smartphones, tablets, Industrial IoT


  • Freenode IRC #libre-soc
  • Website https://libre-soc.org
    • mailing list, git repos, bugtracker etc.