2 * linux/arch/ia64/sn/kernel/sn2/timer.c
4 * Copyright (C) 2003 Silicon Graphics, Inc.
5 * Copyright (C) 2003 Hewlett-Packard Co
6 * David Mosberger <davidm@hpl.hp.com>: updated for new timer-interpolation infrastructure
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/time.h>
13 #include <linux/interrupt.h>
14 #include <linux/clocksource.h>
16 #include <asm/hw_irq.h>
17 #include <asm/timex.h>
19 #include <asm/sn/leds.h>
20 #include <asm/sn/shub_mmr.h>
21 #include <asm/sn/clksupport.h>
23 extern unsigned long sn_rtc_cycles_per_second
;
25 static cycle_t
read_sn2(struct clocksource
*cs
)
27 return (cycle_t
)readq(RTC_COUNTER_ADDR
);
30 static struct clocksource clocksource_sn2
= {
34 .mask
= (1LL << 55) - 1,
35 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
39 * sn udelay uses the RTC instead of the ITC because the ITC is not
40 * synchronized across all CPUs, and the thread may migrate to another CPU
41 * if preemption is enabled.
44 ia64_sn_udelay (unsigned long usecs
)
46 unsigned long start
= rtc_time();
47 unsigned long end
= start
+
48 usecs
* sn_rtc_cycles_per_second
/ 1000000;
50 while (time_before((unsigned long)rtc_time(), end
))
54 void __init
sn_timer_init(void)
56 clocksource_sn2
.archdata
.fsys_mmio
= RTC_COUNTER_ADDR
;
57 clocksource_register_hz(&clocksource_sn2
, sn_rtc_cycles_per_second
);
59 ia64_udelay
= &ia64_sn_udelay
;