threshold = timeout * port->ip_baud / 10 / HZ / 4; 
threshold = timeout * port->ip_baud / 4000; 
static inline int set_rx_timeout(struct ioc4_port *port, int timeout){	int threshold;	port->ip_rx_timeout = timeout;	/* Timeout is in ticks.  Let's figure out how many chars we	 * can receive at the current baud rate in that interval	 * and set the rx threshold to that amount.  There are 4 chars	 * per ring entry, so we'll divide the number of chars that will	 * arrive in timeout by 4.	 */	threshold = timeout * port->ip_baud / 10 / HZ / 4;	if (threshold == 0)		threshold = 1;	/* otherwise we'll intr all the time! */	if ((unsigned)threshold > (unsigned)IOC4_SSCR_RX_THRESHOLD)		return 1;	port->ip_sscr &= ~IOC4_SSCR_RX_THRESHOLD;	port->ip_sscr |= threshold;	writel(port->ip_sscr, &port->ip_serial_regs->sscr);	/* Now set the rx timeout to the given value */	timeout = timeout * IOC4_SRTR_HZ / HZ;	if (timeout > IOC4_SRTR_CNT)		timeout = IOC4_SRTR_CNT;	writel(timeout, &port->ip_serial_regs->srtr);	return 0;}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/6cb2875f8d7e392982229094ad3b6d2f213f48da/ioc4_serial.c/clean/drivers/serial/ioc4_serial.c