2 * linux/arch/arm/kernel/time.c
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 * Modifications for ARM (C) 1994-2001 Russell King
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This file contains the ARM-specific time handling details:
12 * reading the RTC at bootup, etc...
14 #include <linux/export.h>
15 #include <linux/kernel.h>
16 #include <linux/interrupt.h>
17 #include <linux/time.h>
18 #include <linux/init.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/timex.h>
22 #include <linux/errno.h>
23 #include <linux/profile.h>
24 #include <linux/syscore_ops.h>
25 #include <linux/timer.h>
26 #include <linux/irq.h>
28 #include <linux/mc146818rtc.h>
31 #include <asm/thread_info.h>
32 #include <asm/sched_clock.h>
33 #include <asm/stacktrace.h>
34 #include <asm/mach/arch.h>
35 #include <asm/mach/time.h>
40 static struct sys_timer *system_timer;
42 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \
43 defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE)
44 /* this needs a better home */
45 DEFINE_SPINLOCK(rtc_lock);
46 EXPORT_SYMBOL(rtc_lock);
47 #endif /* pc-style 'CMOS' RTC support */
49 /* change this if you have some constant time drift */
50 #define USECS_PER_JIFFY (1000000/HZ)
53 unsigned long profile_pc(struct pt_regs *regs)
55 struct stackframe frame;
57 if (!in_lock_functions(regs->ARM_pc))
60 frame.fp = regs->ARM_fp;
61 frame.sp = regs->ARM_sp;
62 frame.lr = regs->ARM_lr;
63 frame.pc = regs->ARM_pc;
65 int ret = unwind_frame(&frame);
68 } while (in_lock_functions(frame.pc));
72 EXPORT_SYMBOL(profile_pc);
75 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
76 u32 arch_gettimeoffset(void)
78 if (system_timer->offset != NULL)
79 return system_timer->offset() * 1000;
83 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
85 #ifdef CONFIG_LEDS_TIMER
86 static inline void do_leds(void)
88 static unsigned int count = HZ/2;
92 leds_event(led_timer);
100 #ifndef CONFIG_GENERIC_CLOCKEVENTS
102 * Kernel system timer support.
104 void timer_tick(void)
106 profile_tick(CPU_PROFILING);
110 update_process_times(user_mode(get_irq_regs()));
115 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
116 static int timer_suspend(void)
118 if (system_timer->suspend)
119 system_timer->suspend();
124 static void timer_resume(void)
126 if (system_timer->resume)
127 system_timer->resume();
130 #define timer_suspend NULL
131 #define timer_resume NULL
134 static struct syscore_ops timer_syscore_ops = {
135 .suspend = timer_suspend,
136 .resume = timer_resume,
139 static int __init timer_init_syscore_ops(void)
141 register_syscore_ops(&timer_syscore_ops);
146 device_initcall(timer_init_syscore_ops);
148 void __init time_init(void)
150 system_timer = machine_desc->timer;
151 system_timer->init();
152 #ifdef CONFIG_HAVE_SCHED_CLOCK
153 sched_clock_postinit();