I’ve a reason to need to attach a debugger to cboot (in my case on either an AGX or Xavier NX). I can talk to the JTAG DAP enough to read the Coresight ROM, but it seems that some required peripheral is not powered on (or is clock gated). Here’s a dump of what JLink spits out, OpenOCD reacts similarly.
As far as I can tell by poking around after boot with devmem2, the Coresight peripherals are enabled. What am I missing? Do I have to turn on these capabilities via MMIO somewhere?
That’s quite surprising! Do you mean you haven’t externally supported it, or indeed internally it hasn’t been used?
The error output from my adapter (JLink) is given in the first post (and here for convinience) - I’m afraid I haven’t got anything more useful yet, but I’m willing to experiment if anyone has suggestions.