Pull fix-cpu-possible-map into release branch
[linux-2.6] / arch / ia64 / sn / kernel / sn2 / timer.c
1 /*
2  * linux/arch/ia64/sn/kernel/sn2/timer.c
3  *
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
7  */
8
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
15 #include <asm/hw_irq.h>
16 #include <asm/system.h>
17 #include <asm/timex.h>
18
19 #include <asm/sn/leds.h>
20 #include <asm/sn/shub_mmr.h>
21 #include <asm/sn/clksupport.h>
22
23 extern unsigned long sn_rtc_cycles_per_second;
24
25 static struct time_interpolator sn2_interpolator = {
26         .drift = -1,
27         .shift = 10,
28         .mask = (1LL << 55) - 1,
29         .source = TIME_SOURCE_MMIO64
30 };
31
32 /*
33  * sn udelay uses the RTC instead of the ITC because the ITC is not
34  * synchronized across all CPUs, and the thread may migrate to another CPU
35  * if preemption is enabled.
36  */
37 static void
38 ia64_sn_udelay (unsigned long usecs)
39 {
40         unsigned long start = rtc_time();
41         unsigned long end = start +
42                         usecs * sn_rtc_cycles_per_second / 1000000;
43
44         while (time_before((unsigned long)rtc_time(), end))
45                 cpu_relax();
46 }
47
48 void __init sn_timer_init(void)
49 {
50         sn2_interpolator.frequency = sn_rtc_cycles_per_second;
51         sn2_interpolator.addr = RTC_COUNTER_ADDR;
52         register_time_interpolator(&sn2_interpolator);
53
54         ia64_udelay = &ia64_sn_udelay;
55 }