F4PGA: Open Source Toolchain, Interchange

Format and More in New CHIPS Alliance Workgroup

CHIPS Spring Workshop 2022, 2022-04-19

Karol Gugala, kgugala@antmicro.com

Michael Gielda, mgielda@antmicro.com

ANTMICRO

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Founded in 2009, Antmicro provides commercial engineering services, open source platforms, tools and strategic R&D for high-tech products
• Introducing new design methodologies and workflows based on open source
• Comprehensive, end-to-end custom hardware and product development services

SCALING WITH OPEN SOURCE

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F4PGA: Open Source Toolchain, Interchange Format and More

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• We provide open source services to hyperscalers and large corporations, introducing new workflows and design methodologies based on open source
• We help customers reap the benefits of next-gen platforms and open source: vertical integration, full control, portability, rapid iteration
• We believe hardware developers can and should get the benefits of collaboration that open source software developers have!

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CHIPS ALLIANCE

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F4PGA: Open Source Toolchain, Interchange Format and More

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• CHIPS Alliance’s breadth covers many of our focus areas: with our CHIPS partners and customers we work with development of open source cores, IP blocks and tools for RISC-V-based SoCs - cores and peripherals
• As a Platinum Member we lead several tooling efforts, including the creation of the F4PGA Workgroup and the related development

CHIPS ALLIANCE WORKGROUPS

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F4PGA: Open Source Toolchain, Interchange Format and More

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Tools

RISC-V DV

Chisel

Interconnects

Cores

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Rocket

F4PGA

Analog

THE F4PGA WORKGROUP

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Established by CHIPS Alliance based on previous work known as SymbiFlow
• F4PGA = FOSS Flow For FPGA
• Goal: drive open source tooling, IP and �research efforts for FPGAs
• Groups academia members, industry and �FPGA vendors
• Focus on:
• Open source toolchain for FPGAs (previously known as SymbiFlow)
• FPGA Interchange Format
• FPGA Perf Tool
• Many more…

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REPRESENTING MANY PERSPECTIVES

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Academia
• research of new place and route algorithms, novel design approaches
• organize internships, teach classes, extend toolchain in new directions
• Industry
• provide real use cases and requirements
• improve robustness and reliability of toolchain
• FPGA vendors
• collaborate in building out ecosystem
• reach end users
• information, joint roadmaps and planning

CURRENT MEMBERS

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F4PGA: Open Source Toolchain, Interchange Format and More

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F4PGA OPEN TOOLCHAIN

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Fully open source toolchain for FPGA development
• Aims to provide an end-to-end FPGA flow, vendor-neutral
• Makes FPGA development software-centric �and collaborative
• Vital for research, prototyping, niche uses - toolchain openness allows adaptations for various cases
• With open tools, we’re hoping FPGAs can become “mundane” part of future SoCs
• Now part of CHIPS Alliance
• https://f4pga.org/

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F4PGA OPEN TOOLCHAIN

ENABLING DEVELOPMENT FOR EVERYONE

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Currently supported architectures:
• Xilinx 7-Series,
• QuickLogic EOS S3,
• Lattice CrossLink NX,
• Lattice iCE40,
• Lattice ECP5 FPGAs,
• More to come...

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F4PGA OPEN TOOLCHAIN

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F4PGA: Open Source Toolchain, Interchange Format and More

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FPGA INTERCHANGE FORMAT

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Common format for describing FPGA architecture
• Bridging open and proprietary FPGA tools for easier interop
• Lowers barriers to developing new open source tools and new approaches to partial dynamic reconfiguration, exploration of different place & route algorithms, etc.
• Developed in collaboration between Antmicro, Google and Xilinx (now AMD)

FPGA INTERCHANGE FORMAT

SPECIFICATION

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F4PGA: Open Source Toolchain, Interchange Format and More

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• The format is described via a set of schemas defined using the Cap'n'Proto library schema language.
• The library was chosen as it allows for generating consistent data access API while supporting multiple programming languages and being cross-platform.
• All the schemas are available in the GitHub repository: https://github.com/chipsalliance/fpga-interchange-schema

FPGA INTERCHANGE FORMAT

SPECIFICATION

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Define various aspects of the data used by FPGA toolchain
• Device resources
• Logical netlist - a synthesized design
• Physical netlist - placed and routed designs
• Each step is “interchangeable” between tools supporting the format

struct PhysNetlist {

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part @0 : Text;

placements @1 : List(CellPlacement);

physNets @2 : List(PhysNet);

physCells @3 : List(PhysCell);

strList @4 : List(Text) $hashSet();

siteInsts @5 : List(SiteInstance);

properties @6 : List(Property);

nullNet @7 : PhysNet;

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struct PinMapping {

cellPin @0 : StringIdx $stringRef();

bel @1 : StringIdx $stringRef();

belPin @2 : StringIdx $stringRef();

isFixed @3 : Bool;

union {

multi @4 : Void;

otherCell @5 : MultiCellPinMapping;

}

}

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struct MultiCellPinMapping {

multiCell @0 : StringIdx $stringRef();

multiType @1 : StringIdx $stringRef();

}

FPGA INTERCHANGE FORMAT �ADOPTION AND PLANS

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Adoption
• Xilinx RapidWright
• nextpnr
• Q2
• VPR/VTR
• Yosys
• Read more
• Blog by Xilinx (AMD)
• Blog by Google/Antmicro

FPGA PERF TOOL

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Tool by Antmicro to analyzes various FPGA tools for Synthesis and Place & Route (both open source and proprietary)
• Measures tool performance (MHz, resources, runtime, etc), runtime and quality of results
• Tells you how well your design is faring over time to detect regressions
• Repository
• Dashboard

FPGA DATABASE VISUALIZER

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Interactively visualize the F4PGA databases
• Learn more about the FPGA’s internal structure to devise more efficient ways to program them
• Generated by a library allowing you to visualize arbitrary tile-based FPGAs

MORE F4PGA PROJECTS

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F4PGA: Open Source Toolchain, Interchange Format and More

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• FPGA Assembly Parser and Generation Library (FASM)
• Yosys F4PGA plugins
• many more helper tools and repositories

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SUMMARY

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F4PGA: Open Source Toolchain, Interchange Format and More

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• CHIPS Alliance is building an open source hardware ecosystem (FPGA & ASIC)
• The Interchange Format shows that collaboration between many entities - including FPGA vendors - is not only possible but a necessity
• We would want to “transplant” this success also to ASIC domain - interoperability formats are great!
• Practical use cases of F4PGA are possible already now (vendor tooling, IP, research)
• Enabling rapid prototyping and software-driven development of FPGA-based systems in �areas such as ML and video processing

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JOIN US

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F4PGA: Open Source Toolchain, Interchange Format and More

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• Join the F4PGA Workgroup mailing list!
• #f4pga channel on the CHIPS Alliance Slack (bridged with IRC #f4pga channel)
• Join CHIPS Slack workspace
• Follow us on Twitter
• Check the code on GitHub

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THANK YOU

FOR YOUR ATTENTION!