As description , we want to use PCIe3 for NVMe SSD.

We want to know the location of the source code <MUX PCIe to USB0> in PDK8.1 <{PDK}/packages/ti/csl/ sub-directory>.
Q:
1. Dose the PDK8.1 used SERDES3 as USB ? So need to comment out the code muxed SERDES3 as USB0.
2. Is there any Macro(s) definition could control mux OR need to modify the source code to meet my goal <SERDES3 Used as PCIE3 for NVMe SSD> ?
Please help me to understand this.
Best Regards
Murphy.