When the USB Controller on AM64 is configured for Device mode of operation, and the Gadget Zero module is repeatedly loaded/unloaded, it eventually results in Linux hanging:

root@am64xx-evm:~# while true; do modprobe g_zero; modprobe -r g_zero; done

The lockup happens when activating or deactivating the UDC (the USB device controller), which is in kernel function cdns3_gadget_udc_start() or cdns3_gadget_udc_stop() respectively.

When the lockup happens, JTAG can connect to A53_0 or DAP, but is unable to access to DDR, peripheral MMR (tried main_uart0/1), and A53_0 registers.

Resolution:
https://lore.kernel.org/r/20250206125943.786949-1-s-vadapalli@ti.com