+devices_SRC += devices/pci.c # PCI bus.
+devices_SRC += devices/usb.c # USB layer.
+devices_SRC += devices/usb_uhci.c # UHCI device.
+devices_SRC += devices/usb_ehci.c # EHCI device.
+devices_SRC += devices/usb_storage.c # USB mass storage class driver.
+devices_SRC += devices/usb_hub.c # USB hub class driver.