OpenOCD is fond of calling PORT_OFF and PORT_SWD_SETUP frequently, which
played havoc with caching both adapter khz and the DAP delay.
Revert to caching just the DAP delay and reset it when PORT_OFF is called.
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
- Run out of SRAM, it goes quite a lot faster
- Cache the DAP clock frequency
- Read RDATA and write WDATA all in one go, and merge the turnaround
into the ACK phase. Reduces the number of missed PIO SM cycles during an
SWD transfer
Also fix a compiler warning and demote the loglevel of some debug messages.
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
