Hello @EugeneVolkov, I asked about the tegra234-soc-pcie.dtsi file in this post. The file is changed to hardware/nvidia/t23x/nv-public/tegra234.dtsi.
I think; if you want to change PCIe functionalities, you need to change the tegra234-p3737-0000+p3701-0000.dts file rather than the tegra234.dtsi file