[OpenOCD-devel] Debug probe hardware that can read/write target memory directly

[Fewell, E. <ef...@ti...>]

I am currently implementing the Texas Instruments XDS110 debug probe in OpenOCD. The firmware of this probe includes APIs to read and write memory via the target's DAP for ARM Cortex based devices. The OpenOCD software stack does not appear to support this and only can execute DAP register transactions via the probe.

Any ideas on how best to implement this feature from within OpenOCD?  The performance gains are huge for this probe. We see almost 40x improvement between the CMSIS-DAP interface vs using our built-in memory calls on the XDS110.

The memory calls within the ARM Cortex architecture code would need to check if the probe supports direct memory calls then route the call to be handled entirely by the probe firmware. Otherwise, it could continue on to do the memory transaction via DAP register calls.

Edward Fewell
Texas Instruments, Inc