How does Orange Pi 5 Plus get dmc(ram) frequency?

[ajdgsu]

Hi, I'm useing the latest ubuntu 24.04 img for my Orange Pi 5 Plus. Recently I checked the source code of the kernel, and found out Orange Pi 5 Plus dmc should be be defined by rk3588s.dtsi. In that dtsi file, the dmc max frequency table is 2750000000 ,but mine is 2112000000.This frequency definitely not in that dtsi file, and I can't find any dtc/dtsi defind this unique frequency. Also I tried manually specified dmc frequency, like this:
rockchip-rk3588-opp-oc-24ghz.dts.txt
But looks like doesn't work, the opp tables are:
opp_summary.txt
and dmesg report some dmc error:dmesg.txt
Also I found the orangepi offical docs to describe how to write a dts file https://github.com/mfkiwl/rk-open-docs/tree/master/DVFS, but still didn't figure out the solutions. Any ideas?

[pzskc383]

IIRC dram speed us set by pre-bootloader at boot time.

At least i remember something about that in early boot binaries from rockchip.