Porting the Linux Kernel on Jetson nano custom board

Hello. we have designed our custom board with Jetson Nano SOM(with 16G eMMC). But we still have not succeeded in porting the Linux Kernel.Reference the Porting the Linux Kernel section,but i can’t find the folder

hardware/nvidia/platform/t210/porg

in the source code folder just three folders:t18x,t19x and tegra,there is no folder named t210.By the way is thers other detail guid for porting L4T or drivers for Jetson nano .
PS.: the kernel version is:L4T Jetson Nano R32.3.1 Sources

Hi OpenNotes,

Are you sure you downloaded the correct file? There are two sources on the download center. One is for TX2+Xavier while another one is for TX1+Nano.

than you ,i got the wrong file!