prjxray

There are existing reverse engineering efforts for AMD Xilinx devices: https://f4pga.org/ https://f4pga.readthedocs.io/projects/prjxray/en/latest/arch... https://github.com/f4pga/prjxray https://github.com/epfl-vlsc/bitfiltrator

I note that F4PGA (formerly SymbiFlow) Project X-Ray folks are documenting Xilinx FPGAs, hopefully you will be able to replace your use of Vivado at some point: https://f4pga.org/ https://f4pga.github.io/prjxray-db/ https://github.com/F4PGA/prjxray

A bit of a nitpick - LiteX still mostly needs Vivado installed for now for 7 series FPGAs. There's a project that's very far along in reverse engineering the Xilinx bitstream (https://github.com/f4pga/prjxray), but it's still missing many features (PCIe, SERDES, hardware multipliers, etc.). You can run on the open source toolchain but you lose so many of the reasons to actually use a Xilinx FPGA. The only fully supported reverse engineered FPGAs at the moment are the Lattice ECP5(-5G), iCE40, and QuickLogic EOS families. https://f4pga.readthedocs.io/en/latest/status.html

this is true in general but 1) vivado webpack edition (ie free) lets you write (and flash) a bitstream for some of the small chips. i know it at least works for the artix-7 family because i'm doing it every day lately 2) for the artix-7 (and some lattice chips) you supposedly can use OSS (https://github.com/SymbiFlow/prjxray). i haven't tried it yet but one problem i can foresee is that the OSS tools won't infer stuff like brams and dsp. in fact the symbiflow people (i think?) explicitly call this out as the part of the project that's a work in progress. some useful links: https://arxiv.org/abs/1903.10407 https://github.com/YosysHQ/nextpnr https://www.rapidwright.io/

Would LLVM be a better comparison? The GPL'd GNU Compiler Collection (GCC) may be an inaccurate comparison given that nearly all this project's pinned GitHub repos use the ISC license: https://github.com/SymbiFlow/symbiflow-examples/blob/master/... https://github.com/SymbiFlow/symbiflow-docs/blob/master/COPY... https://github.com/SymbiFlow/icestorm/blob/master/COPYING https://github.com/SymbiFlow/prjxray/blob/master/LICENSE https://github.com/SymbiFlow/prjtrellis/blob/master/COPYING (MIT)

Here is a project to reverse engineer the Xilinx series 7 FPGAs to be able to target them with open source tools: https://github.com/SymbiFlow/prjxray

I would like to also add if your curious about more modern FPGA bit-streams there are these two projects which reverse-engineered bit streams for open source synthesis. https://github.com/SymbiFlow/prjxray https://github.com/SymbiFlow/icestorm

No. This is pretty much useless for that. Project X-Ray [1] has been working on reverse engineering the Series 7 bitstream format for a while now, and Dave Shah has an experimental fork [2] of nextpnr that targets some devices using the X-Ray database. [1] - https://github.com/SymbiFlow/prjxray [2] - https://github.com/daveshah1/nextpnr-xilinx

> Maybe brave hackers will reverse engineer bitstream generation As far as I know, the bitstream for 15K/35K/50K Artix-7 is pretty much done, with Kintex-7 and Zynq devices being WIP [1]. I think there are gaps in support for the various hard blocks and PAR at higher layers of the toolchain, but the bitstream reverse engineering per se isn't a maybe-in-the-future thing. [1] https://github.com/SymbiFlow/prjxray

A few years ago that was true, and commercial tools are still horrid and closed and necessary for certain FPGA families. But as of right now you can use[1] the Lattice iCE40 (small, 8k LUTs), Lattice UltraPlus (5k LUTs, DSPs) and Lattice ECP5[2] (~85k LUTs, with 5G SerDes and PCIe Gen 2) with completely open tools. The ECP5 in particular would be well suited for it. And there is a productive effort[3] to do the same for the Artix-7 and other Xilinx 7 Series parts. Even for those parts that are still very much closed, you can load an existing bitstream on them using open tools. Intel Max10, which is the part found on the LimeSDR Mini, is one of those even though we don't have open bitstream documentation for it yet. The major commercial FPGA tools all work Linux at this point too, I use most of them on Ubuntu routinely including Lattice Di

You can check the active project instead. For example, documenting Lattice ECP5 [1] bitstream format or Xiling 7 one [2]. Everyone can help by documenting other formats too. [1] https://github.com/SymbiFlow/prjtrellis [2] https://github.com/SymbiFlow/prjxray

Please let's kill off Vivado once and for all. Awful, massive, unintuitive proprietary software. There are open source tools for programming FPGAs, and they are really great too: https://rwmj.wordpress.com/2018/03/17/playing-with-picorv32-... The Virtex 7 series has been reverse engineered, but we're not quite in the situation where you can use the open source tools yet: https://github.com/SymbiFlow/prjxray

Luckily there is (slow) progress on making good open source tools[1]. The Xilinx 7-series FPGAs were recently reverse-engineered too[2]. [1] https://rwmj.wordpress.com/2018/03/17/playing-with-picorv32-... [2] https://github.com/SymbiFlow/prjxray