[RFC] Event timers on PowerPC

[Alexander Motin]

Hi.

I have refactored PowerPC event timers code to use new event timers
infrastructure. I have successfully tested it on PowerMac G4 and
compiled for MPC85XX.

Patch for HEAD can be found here:
http://people.freebsd.org/~mav/timers_powerpc.patch

With few additional lines:
http://people.freebsd.org/~mav/timers_powerpc2.patch
this patch successfully utilizes dynamic ticks mode of my latest
one-shot timers patch:
http://people.freebsd.org/~mav/timers_oneshot8.patch
, generating only about 50 interrupts per second in idle. With my old
Motorola PowerPC 7400 CPU I haven't noticed any thermal difference,
though it would be interesting to try it on faster/consumptive CPUs.

Comments and reviews welcome.

-- 
Alexander Motin