Where can I get ar71xx related values like pll-data?

For Developers
#1

QCA9558 domywifi dw33d, I suspect the OpenWrt official build was incompatible with my device. So I want to build with some data extracted from my device.
Now I have questions:
How can I determine whether the eth0/eth1 connect to SGMII or RGMII? Where can I get the correct pll-data?
I have the stock firmware and with TTL connected.
It was QSDK, kernel 3.3.8. What information can I get from it?

#2

I follow this got pll-data, but I still don't know how to determine SGMII/RGMII.

For QCA955x series, the PLL registers for eth0 and eth1
can be see in the DTSI as 0x28 and 0x48 respectively.
Therefore the PLL registers can be read from uboot
for each link speed after attempting tftpboot
or another network action using that link speed
with md 0x18050028 1 and md 0x18050048 1.