66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
/*
|
|
* linux/arch/ia64/sn/kernel/sn2/timer.c
|
|
*
|
|
* Copyright (C) 2003 Silicon Graphics, Inc.
|
|
* Copyright (C) 2003 Hewlett-Packard Co
|
|
* David Mosberger <davidm@hpl.hp.com>: updated for new timer-interpolation infrastructure
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/time.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/clocksource.h>
|
|
|
|
#include <asm/hw_irq.h>
|
|
#include <asm/system.h>
|
|
#include <asm/timex.h>
|
|
|
|
#include <asm/sn/leds.h>
|
|
#include <asm/sn/shub_mmr.h>
|
|
#include <asm/sn/clksupport.h>
|
|
|
|
extern unsigned long sn_rtc_cycles_per_second;
|
|
|
|
static cycle_t read_sn2(void)
|
|
{
|
|
return (cycle_t)readq(RTC_COUNTER_ADDR);
|
|
}
|
|
|
|
static struct clocksource clocksource_sn2 = {
|
|
.name = "sn2_rtc",
|
|
.rating = 450,
|
|
.read = read_sn2,
|
|
.mask = (1LL << 55) - 1,
|
|
.mult = 0,
|
|
.shift = 10,
|
|
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
|
|
};
|
|
|
|
/*
|
|
* sn udelay uses the RTC instead of the ITC because the ITC is not
|
|
* synchronized across all CPUs, and the thread may migrate to another CPU
|
|
* if preemption is enabled.
|
|
*/
|
|
static void
|
|
ia64_sn_udelay (unsigned long usecs)
|
|
{
|
|
unsigned long start = rtc_time();
|
|
unsigned long end = start +
|
|
usecs * sn_rtc_cycles_per_second / 1000000;
|
|
|
|
while (time_before((unsigned long)rtc_time(), end))
|
|
cpu_relax();
|
|
}
|
|
|
|
void __init sn_timer_init(void)
|
|
{
|
|
clocksource_sn2.fsys_mmio = RTC_COUNTER_ADDR;
|
|
clocksource_sn2.mult = clocksource_hz2mult(sn_rtc_cycles_per_second,
|
|
clocksource_sn2.shift);
|
|
clocksource_register(&clocksource_sn2);
|
|
|
|
ia64_udelay = &ia64_sn_udelay;
|
|
}
|