Has anybody been able to figure out how to debug a Raspberry Pi 3 model B using SWD? To be clear, I'm looking to debug the Pi itself using SWD. We've tried setting up the GPIO pins to use JTAG-SWD, but we get no reply when sending SWD handshake packets. We've verified that there's no reply from the Pi using a logic analyzer.
We're using TMS (GPIO 13, BCM 27) as SWDIO and TCK (GPIO 22, BCM 25) as SWDCLK. This is in GPIO configuration 4.