What are all the kernel in-built ways to control the CPU frequencies?

No cpufreq stuff. Just the terminal and echo. What are ALL the ways to override the CPU’s frequency and/or enable/disable a CPU? My problem lies with Android (which is why no cpufreq is possible), however I want to be able to override the system on the lowest level, which is the Linux kernel.

Here’s a kicker.

echo 600000 > $cpu/scaling_max_freq
chmod 0444  $cpu/scaling_max_freq

THIS DOESN’T WORK

Values do change and do stay 600Mhz and read-only, but the actual frequency stays as it was.