USB implements the OHCI (Open Host Controller Interface), so there is much more information in that specification than what is present in the 9360 spec. The OHCI spec can be found online.
From that specification:
This bit indicates whether the port is enabled or disabled. The Root Hub may clear this bit when an overcurrent condition, disconnect event, switched-off power, or operational bus error such as babble is detected.
Last updated: Aug 08, 2017