Support for low power mode for powerpc processors

Hi all,
I would like to know whether Linux on PowerPC puts the processor on
low power mode during idle state. Most PowerPC processors support a
low power mode. I am looking to add support for low-power mode in
Linux for AMCC 4xx processors.

My questions are the following:
1) Is tickless kernel integrated into the PowerPC tree?
2) Does Linux kernel puts the processor in low power mode if cpu is
idle, and takes it out of that state on wakeup (triggered by
interrupt/WOL etc)?

Any suggestions/comments would be welcome.

Thanks,
Prodyut