 if (port->membase == NULL) return; 
static void siu_shutdown(struct uart_port *port){	unsigned long flags;	uint8_t lcr;	if (port->membase == NULL)		return;	siu_write(port, UART_IER, 0);	spin_lock_irqsave(&port->lock, flags);	port->mctrl &= ~TIOCM_OUT2;	siu_set_mctrl(port, port->mctrl);	spin_unlock_irqrestore(&port->lock, flags);	lcr = siu_read(port, UART_LCR);	lcr &= ~UART_LCR_SBC;	siu_write(port, UART_LCR, lcr);	siu_clear_fifo(port);	(void)siu_read(port, UART_RX);	if (port->type == PORT_VR41XX_DSIU)		vr41xx_disable_dsiuint(DSIUINT_ALL);	free_irq(port->irq, port);}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/eae936e21bd726f9d9555f2262d439fbcd61dccf/vr41xx_siu.c/buggy/drivers/serial/vr41xx_siu.c