Man page 9 : usb_add_hcd

usb_add_hcd - finish generic HCD structure initialization and register

int usb_add_hcd(struct usb_hcd *  hcd , unsigned int  irqnum , unsigned long  irqflags );

hcd
    the usb_hcd structure to initialize

irqnum
    Interrupt line to allocate

irqflags
    Interrupt type flags

allocate the buffers of consistent memory, register the bus, request the IRQ line, and call the driverAqs reset and start routines.