I am aware that coreboot initializes DRAM and sets its frequency (cache-as-ram) during boot. I would like to know if it is possible to change the DRAM frequency by following the same initialization sequence without rebooting the system (along with preserving the application's memory context).
Yes I had similar thoughts and I think it could work like this:
1) Execute code from ROM 2) There, issue the self refresh cycling to memory controller 3) turn off clocks for memory 4) do whatever else 5) restore clocks/just exit from self refresh (same code as S3 resume)
In theory it could be possible to shift frequency / settings this way, however DQS strobing fine tunes might make it impossible.
Thanks Rudolf