/* *  linux/arch/arm/kernel/time.c * *  Copyright (C) 1991, 1992, 1995  Linus Torvalds *  Modifications for ARM (C) 1994-2001 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * *  This file contains the ARM-specific time handling details: *  reading the RTC at bootup, etc... * *  1994-07-02  Alan Modra *              fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime *  1998-12-20  Updated NTP code according to technical memorandum Jan '96 *              "A Kernel Model for Precision Timekeeping" by Dave Mills */#include <linux/module.h>#include <linux/kernel.h>#include <linux/interrupt.h>#include <linux/time.h>#include <linux/init.h>#include <linux/smp.h>#include <linux/timex.h>#include <linux/errno.h>#include <linux/profile.h>#include <linux/sysdev.h>#include <linux/timer.h>#include <linux/irq.h> #include <linux/mc146818rtc.h> #include <asm/leds.h>#include <asm/thread_info.h>#include <asm/mach/time.h> /* * Our system timer. */struct sys_timer *system_timer; #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)/* this needs a better home */DEFINE_SPINLOCK(rtc_lock); #ifdef CONFIG_RTC_DRV_CMOS_MODULEEXPORT_SYMBOL(rtc_lock);#endif#endif	/* pc-style 'CMOS' RTC support */ /* change this if you have some constant time drift */#define USECS_PER_JIFFY	(1000000/HZ) #ifdef CONFIG_SMPunsigned long profile_pc(struct pt_regs *regs){	unsigned long fp, pc = instruction_pointer(regs); 	if (in_lock_functions(pc)) {		fp = regs->ARM_fp;		pc = pc_pointer(((unsigned long *)fp)[-1]);	} 	return pc;}EXPORT_SYMBOL(profile_pc);#endif /* * hook for setting the RTC's idea of the current time. */int (*set_rtc)(void); #ifndef CONFIG_GENERIC_TIMEstatic unsigned long dummy_gettimeoffset(void){	return 0;}#endif /* * An implementation of printk_clock() independent from * sched_clock().  This avoids non-bootable kernels when * printk_clock is enabled. */unsigned long long printk_clock(void){	return (unsigned long long)(jiffies - INITIAL_JIFFIES) *			(1000000000 / HZ);} static unsigned long next_rtc_update; /* * If we have an externally synchronized linux clock, then update * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be * called as close as possible to 500 ms before the new second * starts. */static inline void do_set_rtc(void){	if (!ntp_synced() || set_rtc == NULL)		return; 	if (next_rtc_update &&	    time_before((unsigned long)xtime.tv_sec, next_rtc_update))		return; 	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&	    xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))		return; 	if (set_rtc())		/*		 * rtc update failed.  Try again in 60s		 */		next_rtc_update = xtime.tv_sec + 60;	else		next_rtc_update = xtime.tv_sec + 660;} #ifdef CONFIG_LEDS static void dummy_leds_event(led_event_t evt){} void (*leds_event)(led_event_t) = dummy_leds_event; struct leds_evt_name {	const char	name[8];	int		on;	int		off;}; static const struct leds_evt_name evt_names[] = {	{ "amber", led_amber_on, led_amber_off },	{ "blue",  led_blue_on,  led_blue_off  },	{ "green", led_green_on, led_green_off },	{ "red",   led_red_on,   led_red_off   },}; static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size){	int ret = -EINVAL, len = strcspn(buf, " "); 	if (len > 0 && buf[len] == '\0')		len--; 	if (strncmp(buf, "claim", len) == 0) {		leds_event(led_claim);		ret = size;	} else if (strncmp(buf, "release", len) == 0) {		leds_event(led_release);		ret = size;	} else {		int i; 		for (i = 0; i < ARRAY_SIZE(evt_names); i++) {			if (strlen(evt_names[i].name) != len ||			    strncmp(buf, evt_names[i].name, len) != 0)				continue;			if (strncmp(buf+len, " on", 3) == 0) {				leds_event(evt_names[i].on);				ret = size;			} else if (strncmp(buf+len, " off", 4) == 0) {				leds_event(evt_names[i].off);				ret = size;			}			break;		}	}	return ret;} static SYSDEV_ATTR(event, 0200, NULL, leds_store); static int leds_suspend(struct sys_device *dev, pm_message_t state){	leds_event(led_stop);	return 0;} static int leds_resume(struct sys_device *dev){	leds_event(led_start);	return 0;} static int leds_shutdown(struct sys_device *dev){	leds_event(led_halted);	return 0;} static struct sysdev_class leds_sysclass = {	set_kset_name("leds"),	.shutdown	= leds_shutdown,	.suspend	= leds_suspend,	.resume		= leds_resume,}; static struct sys_device leds_device = {	.id		= 0,	.cls		= &leds_sysclass,}; static int __init leds_init(void){	int ret;	ret = sysdev_class_register(&leds_sysclass);	if (ret == 0)		ret = sysdev_register(&leds_device);	if (ret == 0)		ret = sysdev_create_file(&leds_device, &attr_event);	return ret;} device_initcall(leds_init); EXPORT_SYMBOL(leds_event);#endif #ifdef CONFIG_LEDS_TIMERstatic inline void do_leds(void){	static unsigned int count = HZ/2; 	if (--count == 0) {		count = HZ/2;		leds_event(led_timer);	}}#else#define	do_leds()#endif #ifndef CONFIG_GENERIC_TIMEvoid do_gettimeofday(struct timeval *tv){	unsigned long flags;	unsigned long seq;	unsigned long usec, sec; 	do {		seq = read_seqbegin_irqsave(&xtime_lock, flags);		usec = system_timer->offset();		sec = xtime.tv_sec;		usec += xtime.tv_nsec / 1000;	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 	/* usec may have gone up a lot: be safe */	while (usec >= 1000000) {		usec -= 1000000;		sec++;	} 	tv->tv_sec = sec;	tv->tv_usec = usec;} EXPORT_SYMBOL(do_gettimeofday); int do_settimeofday(struct timespec *tv){	time_t wtm_sec, sec = tv->tv_sec;	long wtm_nsec, nsec = tv->tv_nsec; 	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)		return -EINVAL; 	write_seqlock_irq(&xtime_lock);	/*	 * This is revolting. We need to set "xtime" correctly. However, the	 * value in this location is the value at the most recent update of	 * wall time.  Discover what correction gettimeofday() would have	 * done, and then undo it!	 */	nsec -= system_timer->offset() * NSEC_PER_USEC; 	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 	set_normalized_timespec(&xtime, sec, nsec);	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 	ntp_clear();	write_sequnlock_irq(&xtime_lock);	clock_was_set();	return 0;} EXPORT_SYMBOL(do_settimeofday);#endif /* !CONFIG_GENERIC_TIME */ /** * save_time_delta - Save the offset between system time and RTC time * @delta: pointer to timespec to store delta * @rtc: pointer to timespec for current RTC time * * Return a delta between the system time and the RTC time, such * that system time can be restored later with restore_time_delta() */void save_time_delta(struct timespec *delta, struct timespec *rtc){	set_normalized_timespec(delta,				xtime.tv_sec - rtc->tv_sec,				xtime.tv_nsec - rtc->tv_nsec);}EXPORT_SYMBOL(save_time_delta); /** * restore_time_delta - Restore the current system time * @delta: delta returned by save_time_delta() * @rtc: pointer to timespec for current RTC time */void restore_time_delta(struct timespec *delta, struct timespec *rtc){	struct timespec ts; 	set_normalized_timespec(&ts,				delta->tv_sec + rtc->tv_sec,				delta->tv_nsec + rtc->tv_nsec); 	do_settimeofday(&ts);}EXPORT_SYMBOL(restore_time_delta); /* * Kernel system timer support. */void timer_tick(void){	profile_tick(CPU_PROFILING);	do_leds();	do_set_rtc();	do_timer(1);#ifndef CONFIG_SMP	update_process_times(user_mode(get_irq_regs()));#endif} #ifdef CONFIG_PMstatic int timer_suspend(struct sys_device *dev, pm_message_t state){	struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 	if (timer->suspend != NULL)		timer->suspend(); 	return 0;} static int timer_resume(struct sys_device *dev){	struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 	if (timer->resume != NULL)		timer->resume(); 	return 0;}#else#define timer_suspend NULL#define timer_resume NULL#endif static struct sysdev_class timer_sysclass = {	set_kset_name("timer"),	.suspend	= timer_suspend,	.resume		= timer_resume,}; #ifdef CONFIG_NO_IDLE_HZstatic int timer_dyn_tick_enable(void){	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;	unsigned long flags;	int ret = -ENODEV; 	if (dyn_tick) {		spin_lock_irqsave(&dyn_tick->lock, flags);		ret = 0;		if (!(dyn_tick->state & DYN_TICK_ENABLED)) {			ret = dyn_tick->enable(); 			if (ret == 0)				dyn_tick->state |= DYN_TICK_ENABLED;		}		spin_unlock_irqrestore(&dyn_tick->lock, flags);	} 	return ret;} static int timer_dyn_tick_disable(void){	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;	unsigned long flags;	int ret = -ENODEV; 	if (dyn_tick) {		spin_lock_irqsave(&dyn_tick->lock, flags);		ret = 0;		if (dyn_tick->state & DYN_TICK_ENABLED) {			ret = dyn_tick->disable(); 			if (ret == 0)				dyn_tick->state &= ~DYN_TICK_ENABLED;		}		spin_unlock_irqrestore(&dyn_tick->lock, flags);	} 	return ret;} /* * Reprogram the system timer for at least the calculated time interval. * This function should be called from the idle thread with IRQs disabled, * immediately before sleeping. */void timer_dyn_reprogram(void){	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;	unsigned long next, seq, flags; 	if (!dyn_tick)		return; 	spin_lock_irqsave(&dyn_tick->lock, flags);	if (dyn_tick->state & DYN_TICK_ENABLED) {		next = next_timer_interrupt();		do {			seq = read_seqbegin(&xtime_lock);			dyn_tick->reprogram(next - jiffies);		} while (read_seqretry(&xtime_lock, seq));	}	spin_unlock_irqrestore(&dyn_tick->lock, flags);} static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf){	return sprintf(buf, "%i\n",		       (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);} static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,				  size_t count){	unsigned int enable = simple_strtoul(buf, NULL, 2); 	if (enable)		timer_dyn_tick_enable();	else		timer_dyn_tick_disable(); 	return count;}static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick); /* * dyntick=enable|disable */static char dyntick_str[4] __initdata = ""; static int __init dyntick_setup(char *str){	if (str)		strlcpy(dyntick_str, str, sizeof(dyntick_str));	return 1;} __setup("dyntick=", dyntick_setup);#endif static int __init timer_init_sysfs(void){	int ret = sysdev_class_register(&timer_sysclass);	if (ret == 0) {		system_timer->dev.cls = &timer_sysclass;		ret = sysdev_register(&system_timer->dev);	} #ifdef CONFIG_NO_IDLE_HZ	if (ret == 0 && system_timer->dyn_tick) {		ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick); 		/*		 * Turn on dynamic tick after calibrate delay		 * for correct bogomips		 */		if (ret == 0 && dyntick_str[0] == 'e')			ret = timer_dyn_tick_enable();	}#endif 	return ret;} 

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