TL,DR: We have native knock processing, with Proteus and Hellen hardware support at the moment. We have very limited amount of testing on real vehicles.
Software knock sensing
We have some progress integrating with conventional knock sensors but it's not ready for end users. We use TPIC/HIP9011 IC for knock sensor integration but no conclusive data.
We believe that we have hip9011 hardware yet nobody has ever actually detected knock with a hip9011, someone would have to figure our calibration approach and test the overall implementation.
Frankenso has hip9011 on-board
Frequency is calculated based on bore, Freq = (900 / (PIF * (bore) / 2))
We also have some results with ion sensing but it's not ready for end users