There's docs and source for some aspects of the VideoCore. I think someone put together an OpenCL implementation, but I don't know how well it works
Edit: That said, I think any sort of OpenCL/GPGPU solution is overkill for this problem. I run Flightaware's dump1090 fork on my Pi and it seems to only use around 30% of one CPU core.
Edit: That said, I think any sort of OpenCL/GPGPU solution is overkill for this problem. I run Flightaware's dump1090 fork on my Pi and it seems to only use around 30% of one CPU core.