On our custom HW design (AM625), we have USB0 configured for host mode, with the ability to use it as a "Recovery" Primary boot mode (external switch to change BOOTMODE bits).
We have successfully booted into our operating system from both eMMC(filesystem mode) as well as USB Host Mode.
When we bootup via USB Host mode, USB0_DRVVBUS is asserted properly and our USB peripheral gets power and we can access it from the OS and its USB driver.
However, when we bootup via eMMC (using the exact same SPL + UBoot images), USB0_DRVVBUS is not asserted, and it does not get asserted when our driver starts either.
It would appear that either the ROM Bootloader or UBoot (when detecting USB boot) are setting something that causes USB0_DVRVBUS to assert properly. In the not working scenario (eMMC boot), we have already tried executing "usb start" from Uboot prompt prior to OS boot, but that does not get things going.
We note that the TRM contents for AM62x USB subsystem are lacking any detail (we gather it is instances of Synopsis DWC3). Can TI provide more documentation on these peripherals and register sets?
What do we need to do to reliably get USB0 going in host mode, with USB0_DRVVBUS properly asserted to provide VBUS to our USB peripheral?
Thanks,
Dan
