BeagleBone, AM335X, USB, and memory location 0x47401c60

On BB, or rather on the TI AM335x, memory location 0x47401c60 can be used to turn the USB power on and off. I’ve used this successfully on my BBB and BBG. E.g.,

However, on BBGW, this technique works for turning USB power off, but hangs the device when attempting to turn it back on.

Does anyone know the meaning of the individual bits at that memory location, or the memory location before and after? Anyone know where I might go looking for such documentation?

The AM335X Technical Reference Manual (page 156) has this description:

Block Name Start Address End Address
USB1 Core 0x4740_1C00 0x4740_1FFF

Unfortunately, there are no details other than “USB1 Core”.