In Windows 7, you can run Device Manager and select the Mass Storage device in the USB Controllers section and look at the Properties/Detail/Location to get something like Port_#0003.Hub_#0004.
I have worked with code that crawls through the registry and makes all kinds of undocumented Windows APIs to link a drive letter to a USB ID since Windows 98 days. Windows 7 was the first OS to at least show the location in Device Manager. Maybe there is a better way these day, but historically it is has been very difficult for an application to discern which USB port the device was running on.
I want to do this in Windows Embedded Compact 7. There is something called a Device Manager, but it does not have a user interface like the one in standard Windows 7. I'm not sure what information I can get from it in my software.
I kind of figured you were talking about firmware, but wasn't sure. I can't say at all about WinCE myself, but I would suggest asking in a Microsoft forum maybe. Sorry I couldn't help, but would be great to know if you find a solution.