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1da177e4 LT |
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> | |
0aa366f3 | 14 | #include <linux/clocksource.h> |
1da177e4 LT |
15 | |
16 | #include <asm/hw_irq.h> | |
17 | #include <asm/system.h> | |
defbb2c9 | 18 | #include <asm/timex.h> |
1da177e4 LT |
19 | |
20 | #include <asm/sn/leds.h> | |
21 | #include <asm/sn/shub_mmr.h> | |
22 | #include <asm/sn/clksupport.h> | |
23 | ||
24 | extern unsigned long sn_rtc_cycles_per_second; | |
25 | ||
8e19608e | 26 | static cycle_t read_sn2(struct clocksource *cs) |
0aa366f3 | 27 | { |
40d48575 | 28 | return (cycle_t)readq(RTC_COUNTER_ADDR); |
0aa366f3 TL |
29 | } |
30 | ||
31 | static struct clocksource clocksource_sn2 = { | |
32 | .name = "sn2_rtc", | |
40d48575 | 33 | .rating = 450, |
0aa366f3 TL |
34 | .read = read_sn2, |
35 | .mask = (1LL << 55) - 1, | |
0aa366f3 | 36 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
1da177e4 LT |
37 | }; |
38 | ||
defbb2c9 | 39 | /* |
40 | * sn udelay uses the RTC instead of the ITC because the ITC is not | |
41 | * synchronized across all CPUs, and the thread may migrate to another CPU | |
42 | * if preemption is enabled. | |
43 | */ | |
44 | static void | |
45 | ia64_sn_udelay (unsigned long usecs) | |
46 | { | |
47 | unsigned long start = rtc_time(); | |
48 | unsigned long end = start + | |
49 | usecs * sn_rtc_cycles_per_second / 1000000; | |
50 | ||
51 | while (time_before((unsigned long)rtc_time(), end)) | |
52 | cpu_relax(); | |
53 | } | |
54 | ||
1da177e4 LT |
55 | void __init sn_timer_init(void) |
56 | { | |
574c44fa | 57 | clocksource_sn2.archdata.fsys_mmio = RTC_COUNTER_ADDR; |
d60c3041 | 58 | clocksource_register_hz(&clocksource_sn2, sn_rtc_cycles_per_second); |
defbb2c9 | 59 | |
60 | ia64_udelay = &ia64_sn_udelay; | |
1da177e4 | 61 | } |