Why isn't there an open-source FPGA?

Question

I'm asking about the FPGA itself - not boards or IP cores or toolchain.The only thing I've found while searching is https://git.slaanesh.org/kfpga/kfpga which is still very new and small, but inspiring.What are the major hurdles that have prevented people from creating an open source FPGA design?

s1dev · Accepted Answer

CPUs you can implement on FPGAs or something else whereas FPGAs are really only useful if you can get it made. Getting the design rules from a foundry usually involves an NDA and you will need (proprietary) EDA tools.Also the utility of open source CPU cores is much higher than an open source FPGA since you're not going to be able to customize it anyway because of mask costs.

nickmqb · Answer

This FPGA is not open source by design, but this project seems fairly complete: http://www.clifford.at/icestorm/ "Project IceStorm aims at documenting the bitstream format of Lattice iCE40 FPGAs and providing simple tools for analyzing and creating bitstream files."Lattice (the FPGA's manufacturer) seems open-minded regarding such efforts: https://twitter.com/latticesemi/status/1269115302140231682

zw123456 · Answer

I like the idea. I do a lot of FPGA work and have often thought the same thing. The link is very interesting. I think part of the challenge would be how do you get the foundry capacity to actually produce it. And how to pay for that, who will buy it etc. etc. Those questions are beyond me, but I do think that if it were to get momentum there could be a lot of interest.

redis_mlc · Answer

Xilinx has like 2,000 FPGA patents, proudly displayed on plaques on their cafeteria wall.So you would have to navigate around those.

Why isn't there an open-source FPGA?

I'm asking about the FPGA itself - not boards or IP cores or toolchain.
The only thing I've found while searching is https://git.slaanesh.org/kfpga/kfpga which is still very new and small, but inspiring.
What are the major hurdles that have prevented people from creating an open source FPGA design?

Xilinx has like 2,000 FPGA patents, proudly displayed on plaques on their cafeteria wall.
So you would have to navigate around those.