The cpufreq subsystem is a Linux kernel subsystem responsible for managing the CPU frequency. It's commonly used in laptops to reduce power usage when idle.
On the S3C2410, adjusting the CPU frequency changes the clocks for almost all devices on the chip. This means that, to write a cpufreq driver for the S3C2410, you have to also adjust some values on almost all devices.
This project aims to implement the cpufreq driver (which manages the CPU frequency transitions) and a cpufreq notifier for all the affected drivers (to do two things: quiesce the device before the change, and adjust the frequency after the change).
The most recent version of the code can be found at http://repo.or.cz/w/linux-2.6/s3c2410-cpufreq.git on the branches s3c2410-cpufreq (for code which applies on top of the upstream "git HEAD" kernel) and s3c2410-cpufreq-gta01 (for code which applies on top of the OpenMoko patched kernel).