what to do config the the pice interior loopback of lx2160ardb board?pls tell me the step in uboot environment?
PCIe internal loopback setup is not supported in U-Boot.
The only supported method is to use CodeWarrior QCVS SerDes Tool:
https://www.nxp.com/docs/en/user-guide/QCVS_SerDes_User_Guide.pdf