I am instantiating both a Cortex-M1 and a Cortex-M3 in a Xilinx 7-series FPGA and need SWD access to both cores.
Do these cores support SWD multi-drop? If so, is there a reference design - or just any design hints - available?
The stand-alone DAPs which come as part of these processors do not include multi-drop.
If you have connected the processor to a full CoreSight DAP, or have constructed a DAP from discrete parts, then it is possible that you support multi-drop depending on which DP component is included.
Essentially you we need additional components (available via CoreSight) to be able to instantiate both processors and communicate via SWD.