OpenFPGA: An Opensource Framework Enabling Rapid Prototyping of Customizable FPGAs

Driven by the strong need in data processing applications, Field Programmable Gate Arrays (FPGAs) are playing an ever-increasing role as programmable accelerators in modern computing systems. To fully unlock processing capabilities for domain-specific applications, FPGA architectures have to be tailored for seamless cooperation with other computing resources. However, prototyping and bringing to production a customized FPGA is a costly and complex endeavor even for industrial vendors. In this paper, we introduce OpenFPGA, an opensource framework that enables rapid prototyping of customizable FPGA architectures through a semi-custom design approach. We propose an XML-to-Prototype design flow, where the Verilog netlists of a full FPGA fabric can be autogenerated using an extension of the XML language from the VTR framework and then fed into a back-end flow to generate production-ready layouts. OpenFPGA also includes a general-purpose Verilog-to-Bitstream generator for any FPGA described by the XML language. We demonstrate the capability of this automatic design flow with a Stratix IV-like FPGA architecture using a commercial 40nm technology node, and perform a detailed comparison to its academic and commercial counterparts. Compared to the current state-of-art academic results, our FPGA fabric reduces the area by 1:75 and the delay by 3 on average. In addition, OpenFPGA significantly reduces the gap between semi-custom designed FPGAs and fully-optimized commercial products with a penalty of only 60% in area and 30% in delay, respectively.