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/module.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/sysdev.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 /* this needs a better home */
44 DEFINE_SPINLOCK(rtc_lock);
46 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
47 EXPORT_SYMBOL(rtc_lock);
49 #endif /* pc-style 'CMOS' RTC support */
51 /* change this if you have some constant time drift */
52 #define USECS_PER_JIFFY (1000000/HZ)
55 unsigned long profile_pc(struct pt_regs *regs)
57 struct stackframe frame;
59 if (!in_lock_functions(regs->ARM_pc))
62 frame.fp = regs->ARM_fp;
63 frame.sp = regs->ARM_sp;
64 frame.lr = regs->ARM_lr;
65 frame.pc = regs->ARM_pc;
67 int ret = unwind_frame(&frame);
70 } while (in_lock_functions(frame.pc));
74 EXPORT_SYMBOL(profile_pc);
77 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
78 u32 arch_gettimeoffset(void)
80 if (system_timer->offset != NULL)
81 return system_timer->offset() * 1000;
85 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
87 #ifdef CONFIG_LEDS_TIMER
88 static inline void do_leds(void)
90 static unsigned int count = HZ/2;
94 leds_event(led_timer);
102 #ifndef CONFIG_GENERIC_CLOCKEVENTS
104 * Kernel system timer support.
106 void timer_tick(void)
108 profile_tick(CPU_PROFILING);
110 write_seqlock(&xtime_lock);
112 write_sequnlock(&xtime_lock);
114 update_process_times(user_mode(get_irq_regs()));
119 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
120 static int timer_suspend(struct sys_device *dev, pm_message_t state)
122 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
124 if (timer->suspend != NULL)
130 static int timer_resume(struct sys_device *dev)
132 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
134 if (timer->resume != NULL)
140 #define timer_suspend NULL
141 #define timer_resume NULL
144 static struct sysdev_class timer_sysclass = {
146 .suspend = timer_suspend,
147 .resume = timer_resume,
150 static int __init timer_init_sysfs(void)
152 int ret = sysdev_class_register(&timer_sysclass);
154 system_timer->dev.cls = &timer_sysclass;
155 ret = sysdev_register(&system_timer->dev);
161 device_initcall(timer_init_sysfs);
163 void __init time_init(void)
165 system_timer = machine_desc->timer;
166 system_timer->init();
167 #ifdef CONFIG_HAVE_SCHED_CLOCK
168 sched_clock_postinit();