/* * 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 <asm/leds.h> #include <asm/thread_info.h> #include <asm/mach/time.h> /* * Our system timer. */ struct sys_timer *system_timer; extern unsigned long wall_jiffies; /* this needs a better home */ DEFINE_SPINLOCK(rtc_lock); #ifdef CONFIG_SA1100_RTC_MODULE EXPORT_SYMBOL(rtc_lock); #endif /* change this if you have some constant time drift */ #define USECS_PER_JIFFY (1000000/HZ) #ifdef CONFIG_SMP unsigned 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); static unsigned long dummy_gettimeoffset(void) { return 0; } /* * Scheduler clock - returns current time in nanosec units. * This is the default implementation. Sub-architecture * implementations can override this. */ unsigned long long __attribute__((weak)) sched_clock(void) { return (unsigned long long)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_TIMER static inline void do_leds(void) { static unsigned int count = 50; if (--count == 0) { count = 50; leds_event(led_timer); } } #else #define do_leds() #endif void do_gettimeofday(struct timeval *tv) { unsigned long flags; unsigned long seq; unsigned long usec, sec, lost; do { seq = read_seqbegin_irqsave(&xtime_lock, flags); usec = system_timer->offset(); lost = jiffies - wall_jiffies; if (lost) usec += lost * USECS_PER_JIFFY; 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; nsec -= (jiffies - wall_jiffies) * TICK_NSEC; 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); /** * 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(struct pt_regs *regs) { profile_tick(CPU_PROFILING, regs); do_leds(); do_set_rtc(); do_timer(regs); #ifndef CONFIG_SMP update_process_times(user_mode(regs)); #endif } #ifdef CONFIG_PM static 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_HZ static 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; } device_initcall(timer_init_sysfs); void __init time_init(void) { if (system_timer->offset == NULL) system_timer->offset = dummy_gettimeoffset; system_timer->init(); #ifdef CONFIG_NO_IDLE_HZ if (system_timer->dyn_tick) system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED; #endif }