linux interrupt

port->irq = UARTIntNumberGet(port->iobase);
err = request_irq(port->irq, m200_uart_irq_handler, port->irqflags, 
                  m200_port->name, port);

static inline int __must_check
request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
const char *name, void *dev)
{
return request_threaded_irq(irq, handler, NULL, flags, name, dev);
}
request_irq -> request_threaded_irq -> __setup_irq ->

request_irq /include/linux/interrupt.h
request_threaded_irq /kernel/irq/manage.c
__setup_irq /kernel/irq/manage.c