I'm trying to run a real ss10 openboot prom image rather than
the supplied prom image and found some issues with the way
counters and timers are implemented. It appears that the processor
and system counter/timers are not independent. The system
config register actually configures the processor counter/timers
and the config register is actually a bit mask of the counter/timer
to configure. 1, 2, 4, and 8 are used to as config values for each
processor counter/timer and 0xf is used for setting all of them.
This isn't apparent in the slaveio documentation because it is
for a single cpu only.
Because the system config register configures the processor
timers, it needs access to all the processor timers (or the
processor timers need access to the system timer). This isn't
how it's currently implemented.
