11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/arch/arm/kernel/time.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1995 Linus Torvalds 51da177e4SLinus Torvalds * Modifications for ARM (C) 1994-2001 Russell King 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * This program is free software; you can redistribute it and/or modify 81da177e4SLinus Torvalds * it under the terms of the GNU General Public License version 2 as 91da177e4SLinus Torvalds * published by the Free Software Foundation. 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds * This file contains the ARM-specific time handling details: 121da177e4SLinus Torvalds * reading the RTC at bootup, etc... 131da177e4SLinus Torvalds * 141da177e4SLinus Torvalds * 1994-07-02 Alan Modra 151da177e4SLinus Torvalds * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime 161da177e4SLinus Torvalds * 1998-12-20 Updated NTP code according to technical memorandum Jan '96 171da177e4SLinus Torvalds * "A Kernel Model for Precision Timekeeping" by Dave Mills 181da177e4SLinus Torvalds */ 191da177e4SLinus Torvalds #include <linux/config.h> 201da177e4SLinus Torvalds #include <linux/module.h> 211da177e4SLinus Torvalds #include <linux/kernel.h> 221da177e4SLinus Torvalds #include <linux/interrupt.h> 231da177e4SLinus Torvalds #include <linux/time.h> 241da177e4SLinus Torvalds #include <linux/init.h> 251da177e4SLinus Torvalds #include <linux/smp.h> 261da177e4SLinus Torvalds #include <linux/timex.h> 271da177e4SLinus Torvalds #include <linux/errno.h> 281da177e4SLinus Torvalds #include <linux/profile.h> 291da177e4SLinus Torvalds #include <linux/sysdev.h> 301da177e4SLinus Torvalds #include <linux/timer.h> 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds #include <asm/leds.h> 331da177e4SLinus Torvalds #include <asm/thread_info.h> 341da177e4SLinus Torvalds #include <asm/mach/time.h> 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds /* 371da177e4SLinus Torvalds * Our system timer. 381da177e4SLinus Torvalds */ 391da177e4SLinus Torvalds struct sys_timer *system_timer; 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds extern unsigned long wall_jiffies; 421da177e4SLinus Torvalds 431da177e4SLinus Torvalds /* this needs a better home */ 441da177e4SLinus Torvalds DEFINE_SPINLOCK(rtc_lock); 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds #ifdef CONFIG_SA1100_RTC_MODULE 471da177e4SLinus Torvalds EXPORT_SYMBOL(rtc_lock); 481da177e4SLinus Torvalds #endif 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds /* change this if you have some constant time drift */ 511da177e4SLinus Torvalds #define USECS_PER_JIFFY (1000000/HZ) 521da177e4SLinus Torvalds 531da177e4SLinus Torvalds #ifdef CONFIG_SMP 541da177e4SLinus Torvalds unsigned long profile_pc(struct pt_regs *regs) 551da177e4SLinus Torvalds { 561da177e4SLinus Torvalds unsigned long fp, pc = instruction_pointer(regs); 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds if (in_lock_functions(pc)) { 591da177e4SLinus Torvalds fp = regs->ARM_fp; 601da177e4SLinus Torvalds pc = pc_pointer(((unsigned long *)fp)[-1]); 611da177e4SLinus Torvalds } 621da177e4SLinus Torvalds 631da177e4SLinus Torvalds return pc; 641da177e4SLinus Torvalds } 651da177e4SLinus Torvalds EXPORT_SYMBOL(profile_pc); 661da177e4SLinus Torvalds #endif 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds /* 691da177e4SLinus Torvalds * hook for setting the RTC's idea of the current time. 701da177e4SLinus Torvalds */ 711da177e4SLinus Torvalds int (*set_rtc)(void); 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds static unsigned long dummy_gettimeoffset(void) 741da177e4SLinus Torvalds { 751da177e4SLinus Torvalds return 0; 761da177e4SLinus Torvalds } 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds /* 791da177e4SLinus Torvalds * Scheduler clock - returns current time in nanosec units. 801da177e4SLinus Torvalds * This is the default implementation. Sub-architecture 811da177e4SLinus Torvalds * implementations can override this. 821da177e4SLinus Torvalds */ 831da177e4SLinus Torvalds unsigned long long __attribute__((weak)) sched_clock(void) 841da177e4SLinus Torvalds { 851da177e4SLinus Torvalds return (unsigned long long)jiffies * (1000000000 / HZ); 861da177e4SLinus Torvalds } 871da177e4SLinus Torvalds 881da177e4SLinus Torvalds static unsigned long next_rtc_update; 891da177e4SLinus Torvalds 901da177e4SLinus Torvalds /* 911da177e4SLinus Torvalds * If we have an externally synchronized linux clock, then update 921da177e4SLinus Torvalds * CMOS clock accordingly every ~11 minutes. set_rtc() has to be 931da177e4SLinus Torvalds * called as close as possible to 500 ms before the new second 941da177e4SLinus Torvalds * starts. 951da177e4SLinus Torvalds */ 961da177e4SLinus Torvalds static inline void do_set_rtc(void) 971da177e4SLinus Torvalds { 98b149ee22Sjohn stultz if (!ntp_synced() || set_rtc == NULL) 991da177e4SLinus Torvalds return; 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds if (next_rtc_update && 1021da177e4SLinus Torvalds time_before((unsigned long)xtime.tv_sec, next_rtc_update)) 1031da177e4SLinus Torvalds return; 1041da177e4SLinus Torvalds 1051da177e4SLinus Torvalds if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && 1061da177e4SLinus Torvalds xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) 1071da177e4SLinus Torvalds return; 1081da177e4SLinus Torvalds 1091da177e4SLinus Torvalds if (set_rtc()) 1101da177e4SLinus Torvalds /* 1111da177e4SLinus Torvalds * rtc update failed. Try again in 60s 1121da177e4SLinus Torvalds */ 1131da177e4SLinus Torvalds next_rtc_update = xtime.tv_sec + 60; 1141da177e4SLinus Torvalds else 1151da177e4SLinus Torvalds next_rtc_update = xtime.tv_sec + 660; 1161da177e4SLinus Torvalds } 1171da177e4SLinus Torvalds 1181da177e4SLinus Torvalds #ifdef CONFIG_LEDS 1191da177e4SLinus Torvalds 1201da177e4SLinus Torvalds static void dummy_leds_event(led_event_t evt) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds } 1231da177e4SLinus Torvalds 1241da177e4SLinus Torvalds void (*leds_event)(led_event_t) = dummy_leds_event; 1251da177e4SLinus Torvalds 1261da177e4SLinus Torvalds struct leds_evt_name { 1271da177e4SLinus Torvalds const char name[8]; 1281da177e4SLinus Torvalds int on; 1291da177e4SLinus Torvalds int off; 1301da177e4SLinus Torvalds }; 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds static const struct leds_evt_name evt_names[] = { 1331da177e4SLinus Torvalds { "amber", led_amber_on, led_amber_off }, 1341da177e4SLinus Torvalds { "blue", led_blue_on, led_blue_off }, 1351da177e4SLinus Torvalds { "green", led_green_on, led_green_off }, 1361da177e4SLinus Torvalds { "red", led_red_on, led_red_off }, 1371da177e4SLinus Torvalds }; 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size) 1401da177e4SLinus Torvalds { 1411da177e4SLinus Torvalds int ret = -EINVAL, len = strcspn(buf, " "); 1421da177e4SLinus Torvalds 1431da177e4SLinus Torvalds if (len > 0 && buf[len] == '\0') 1441da177e4SLinus Torvalds len--; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds if (strncmp(buf, "claim", len) == 0) { 1471da177e4SLinus Torvalds leds_event(led_claim); 1481da177e4SLinus Torvalds ret = size; 1491da177e4SLinus Torvalds } else if (strncmp(buf, "release", len) == 0) { 1501da177e4SLinus Torvalds leds_event(led_release); 1511da177e4SLinus Torvalds ret = size; 1521da177e4SLinus Torvalds } else { 1531da177e4SLinus Torvalds int i; 1541da177e4SLinus Torvalds 1551da177e4SLinus Torvalds for (i = 0; i < ARRAY_SIZE(evt_names); i++) { 1561da177e4SLinus Torvalds if (strlen(evt_names[i].name) != len || 1571da177e4SLinus Torvalds strncmp(buf, evt_names[i].name, len) != 0) 1581da177e4SLinus Torvalds continue; 1591da177e4SLinus Torvalds if (strncmp(buf+len, " on", 3) == 0) { 1601da177e4SLinus Torvalds leds_event(evt_names[i].on); 1611da177e4SLinus Torvalds ret = size; 1621da177e4SLinus Torvalds } else if (strncmp(buf+len, " off", 4) == 0) { 1631da177e4SLinus Torvalds leds_event(evt_names[i].off); 1641da177e4SLinus Torvalds ret = size; 1651da177e4SLinus Torvalds } 1661da177e4SLinus Torvalds break; 1671da177e4SLinus Torvalds } 1681da177e4SLinus Torvalds } 1691da177e4SLinus Torvalds return ret; 1701da177e4SLinus Torvalds } 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds static SYSDEV_ATTR(event, 0200, NULL, leds_store); 1731da177e4SLinus Torvalds 1741da177e4SLinus Torvalds static int leds_suspend(struct sys_device *dev, pm_message_t state) 1751da177e4SLinus Torvalds { 1761da177e4SLinus Torvalds leds_event(led_stop); 1771da177e4SLinus Torvalds return 0; 1781da177e4SLinus Torvalds } 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds static int leds_resume(struct sys_device *dev) 1811da177e4SLinus Torvalds { 1821da177e4SLinus Torvalds leds_event(led_start); 1831da177e4SLinus Torvalds return 0; 1841da177e4SLinus Torvalds } 1851da177e4SLinus Torvalds 1861da177e4SLinus Torvalds static int leds_shutdown(struct sys_device *dev) 1871da177e4SLinus Torvalds { 1881da177e4SLinus Torvalds leds_event(led_halted); 1891da177e4SLinus Torvalds return 0; 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds static struct sysdev_class leds_sysclass = { 1931da177e4SLinus Torvalds set_kset_name("leds"), 1941da177e4SLinus Torvalds .shutdown = leds_shutdown, 1951da177e4SLinus Torvalds .suspend = leds_suspend, 1961da177e4SLinus Torvalds .resume = leds_resume, 1971da177e4SLinus Torvalds }; 1981da177e4SLinus Torvalds 1991da177e4SLinus Torvalds static struct sys_device leds_device = { 2001da177e4SLinus Torvalds .id = 0, 2011da177e4SLinus Torvalds .cls = &leds_sysclass, 2021da177e4SLinus Torvalds }; 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds static int __init leds_init(void) 2051da177e4SLinus Torvalds { 2061da177e4SLinus Torvalds int ret; 2071da177e4SLinus Torvalds ret = sysdev_class_register(&leds_sysclass); 2081da177e4SLinus Torvalds if (ret == 0) 2091da177e4SLinus Torvalds ret = sysdev_register(&leds_device); 2101da177e4SLinus Torvalds if (ret == 0) 2111da177e4SLinus Torvalds ret = sysdev_create_file(&leds_device, &attr_event); 2121da177e4SLinus Torvalds return ret; 2131da177e4SLinus Torvalds } 2141da177e4SLinus Torvalds 2151da177e4SLinus Torvalds device_initcall(leds_init); 2161da177e4SLinus Torvalds 2171da177e4SLinus Torvalds EXPORT_SYMBOL(leds_event); 2181da177e4SLinus Torvalds #endif 2191da177e4SLinus Torvalds 2201da177e4SLinus Torvalds #ifdef CONFIG_LEDS_TIMER 2211da177e4SLinus Torvalds static inline void do_leds(void) 2221da177e4SLinus Torvalds { 2231da177e4SLinus Torvalds static unsigned int count = 50; 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvalds if (--count == 0) { 2261da177e4SLinus Torvalds count = 50; 2271da177e4SLinus Torvalds leds_event(led_timer); 2281da177e4SLinus Torvalds } 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds #else 2311da177e4SLinus Torvalds #define do_leds() 2321da177e4SLinus Torvalds #endif 2331da177e4SLinus Torvalds 2341da177e4SLinus Torvalds void do_gettimeofday(struct timeval *tv) 2351da177e4SLinus Torvalds { 2361da177e4SLinus Torvalds unsigned long flags; 2371da177e4SLinus Torvalds unsigned long seq; 2381da177e4SLinus Torvalds unsigned long usec, sec, lost; 2391da177e4SLinus Torvalds 2401da177e4SLinus Torvalds do { 2411da177e4SLinus Torvalds seq = read_seqbegin_irqsave(&xtime_lock, flags); 2421da177e4SLinus Torvalds usec = system_timer->offset(); 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds lost = jiffies - wall_jiffies; 2451da177e4SLinus Torvalds if (lost) 2461da177e4SLinus Torvalds usec += lost * USECS_PER_JIFFY; 2471da177e4SLinus Torvalds 2481da177e4SLinus Torvalds sec = xtime.tv_sec; 2491da177e4SLinus Torvalds usec += xtime.tv_nsec / 1000; 2501da177e4SLinus Torvalds } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds /* usec may have gone up a lot: be safe */ 2531da177e4SLinus Torvalds while (usec >= 1000000) { 2541da177e4SLinus Torvalds usec -= 1000000; 2551da177e4SLinus Torvalds sec++; 2561da177e4SLinus Torvalds } 2571da177e4SLinus Torvalds 2581da177e4SLinus Torvalds tv->tv_sec = sec; 2591da177e4SLinus Torvalds tv->tv_usec = usec; 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds 2621da177e4SLinus Torvalds EXPORT_SYMBOL(do_gettimeofday); 2631da177e4SLinus Torvalds 2641da177e4SLinus Torvalds int do_settimeofday(struct timespec *tv) 2651da177e4SLinus Torvalds { 2661da177e4SLinus Torvalds time_t wtm_sec, sec = tv->tv_sec; 2671da177e4SLinus Torvalds long wtm_nsec, nsec = tv->tv_nsec; 2681da177e4SLinus Torvalds 2691da177e4SLinus Torvalds if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 2701da177e4SLinus Torvalds return -EINVAL; 2711da177e4SLinus Torvalds 2721da177e4SLinus Torvalds write_seqlock_irq(&xtime_lock); 2731da177e4SLinus Torvalds /* 2741da177e4SLinus Torvalds * This is revolting. We need to set "xtime" correctly. However, the 2751da177e4SLinus Torvalds * value in this location is the value at the most recent update of 2761da177e4SLinus Torvalds * wall time. Discover what correction gettimeofday() would have 2771da177e4SLinus Torvalds * done, and then undo it! 2781da177e4SLinus Torvalds */ 2791da177e4SLinus Torvalds nsec -= system_timer->offset() * NSEC_PER_USEC; 2801da177e4SLinus Torvalds nsec -= (jiffies - wall_jiffies) * TICK_NSEC; 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 2831da177e4SLinus Torvalds wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 2841da177e4SLinus Torvalds 2851da177e4SLinus Torvalds set_normalized_timespec(&xtime, sec, nsec); 2861da177e4SLinus Torvalds set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 2871da177e4SLinus Torvalds 288b149ee22Sjohn stultz ntp_clear(); 2891da177e4SLinus Torvalds write_sequnlock_irq(&xtime_lock); 2901da177e4SLinus Torvalds clock_was_set(); 2911da177e4SLinus Torvalds return 0; 2921da177e4SLinus Torvalds } 2931da177e4SLinus Torvalds 2941da177e4SLinus Torvalds EXPORT_SYMBOL(do_settimeofday); 2951da177e4SLinus Torvalds 2961da177e4SLinus Torvalds /** 2971da177e4SLinus Torvalds * save_time_delta - Save the offset between system time and RTC time 2981da177e4SLinus Torvalds * @delta: pointer to timespec to store delta 2991da177e4SLinus Torvalds * @rtc: pointer to timespec for current RTC time 3001da177e4SLinus Torvalds * 3011da177e4SLinus Torvalds * Return a delta between the system time and the RTC time, such 3021da177e4SLinus Torvalds * that system time can be restored later with restore_time_delta() 3031da177e4SLinus Torvalds */ 3041da177e4SLinus Torvalds void save_time_delta(struct timespec *delta, struct timespec *rtc) 3051da177e4SLinus Torvalds { 3061da177e4SLinus Torvalds set_normalized_timespec(delta, 3071da177e4SLinus Torvalds xtime.tv_sec - rtc->tv_sec, 3081da177e4SLinus Torvalds xtime.tv_nsec - rtc->tv_nsec); 3091da177e4SLinus Torvalds } 3101da177e4SLinus Torvalds EXPORT_SYMBOL(save_time_delta); 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds /** 3131da177e4SLinus Torvalds * restore_time_delta - Restore the current system time 3141da177e4SLinus Torvalds * @delta: delta returned by save_time_delta() 3151da177e4SLinus Torvalds * @rtc: pointer to timespec for current RTC time 3161da177e4SLinus Torvalds */ 3171da177e4SLinus Torvalds void restore_time_delta(struct timespec *delta, struct timespec *rtc) 3181da177e4SLinus Torvalds { 3191da177e4SLinus Torvalds struct timespec ts; 3201da177e4SLinus Torvalds 3211da177e4SLinus Torvalds set_normalized_timespec(&ts, 3221da177e4SLinus Torvalds delta->tv_sec + rtc->tv_sec, 3231da177e4SLinus Torvalds delta->tv_nsec + rtc->tv_nsec); 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds do_settimeofday(&ts); 3261da177e4SLinus Torvalds } 3271da177e4SLinus Torvalds EXPORT_SYMBOL(restore_time_delta); 3281da177e4SLinus Torvalds 3291da177e4SLinus Torvalds /* 3301da177e4SLinus Torvalds * Kernel system timer support. 3311da177e4SLinus Torvalds */ 3321da177e4SLinus Torvalds void timer_tick(struct pt_regs *regs) 3331da177e4SLinus Torvalds { 3341da177e4SLinus Torvalds profile_tick(CPU_PROFILING, regs); 3351da177e4SLinus Torvalds do_leds(); 3361da177e4SLinus Torvalds do_set_rtc(); 3371da177e4SLinus Torvalds do_timer(regs); 3381da177e4SLinus Torvalds #ifndef CONFIG_SMP 3391da177e4SLinus Torvalds update_process_times(user_mode(regs)); 3401da177e4SLinus Torvalds #endif 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds 3431da177e4SLinus Torvalds #ifdef CONFIG_PM 3441da177e4SLinus Torvalds static int timer_suspend(struct sys_device *dev, pm_message_t state) 3451da177e4SLinus Torvalds { 3461da177e4SLinus Torvalds struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds if (timer->suspend != NULL) 3491da177e4SLinus Torvalds timer->suspend(); 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds return 0; 3521da177e4SLinus Torvalds } 3531da177e4SLinus Torvalds 3541da177e4SLinus Torvalds static int timer_resume(struct sys_device *dev) 3551da177e4SLinus Torvalds { 3561da177e4SLinus Torvalds struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 3571da177e4SLinus Torvalds 3581da177e4SLinus Torvalds if (timer->resume != NULL) 3591da177e4SLinus Torvalds timer->resume(); 3601da177e4SLinus Torvalds 3611da177e4SLinus Torvalds return 0; 3621da177e4SLinus Torvalds } 3631da177e4SLinus Torvalds #else 3641da177e4SLinus Torvalds #define timer_suspend NULL 3651da177e4SLinus Torvalds #define timer_resume NULL 3661da177e4SLinus Torvalds #endif 3671da177e4SLinus Torvalds 3681da177e4SLinus Torvalds static struct sysdev_class timer_sysclass = { 3691da177e4SLinus Torvalds set_kset_name("timer"), 3701da177e4SLinus Torvalds .suspend = timer_suspend, 3711da177e4SLinus Torvalds .resume = timer_resume, 3721da177e4SLinus Torvalds }; 3731da177e4SLinus Torvalds 3748749af68SRussell King #ifdef CONFIG_NO_IDLE_HZ 3758749af68SRussell King static int timer_dyn_tick_enable(void) 3768749af68SRussell King { 3778749af68SRussell King struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 3788749af68SRussell King unsigned long flags; 3798749af68SRussell King int ret = -ENODEV; 3808749af68SRussell King 3818749af68SRussell King if (dyn_tick) { 3828749af68SRussell King write_seqlock_irqsave(&xtime_lock, flags); 3838749af68SRussell King ret = 0; 3848749af68SRussell King if (!(dyn_tick->state & DYN_TICK_ENABLED)) { 3858749af68SRussell King ret = dyn_tick->enable(); 3868749af68SRussell King 3878749af68SRussell King if (ret == 0) 3888749af68SRussell King dyn_tick->state |= DYN_TICK_ENABLED; 3898749af68SRussell King } 3908749af68SRussell King write_sequnlock_irqrestore(&xtime_lock, flags); 3918749af68SRussell King } 3928749af68SRussell King 3938749af68SRussell King return ret; 3948749af68SRussell King } 3958749af68SRussell King 3968749af68SRussell King static int timer_dyn_tick_disable(void) 3978749af68SRussell King { 3988749af68SRussell King struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 3998749af68SRussell King unsigned long flags; 4008749af68SRussell King int ret = -ENODEV; 4018749af68SRussell King 4028749af68SRussell King if (dyn_tick) { 4038749af68SRussell King write_seqlock_irqsave(&xtime_lock, flags); 4048749af68SRussell King ret = 0; 4058749af68SRussell King if (dyn_tick->state & DYN_TICK_ENABLED) { 4068749af68SRussell King ret = dyn_tick->disable(); 4078749af68SRussell King 4088749af68SRussell King if (ret == 0) 4098749af68SRussell King dyn_tick->state &= ~DYN_TICK_ENABLED; 4108749af68SRussell King } 4118749af68SRussell King write_sequnlock_irqrestore(&xtime_lock, flags); 4128749af68SRussell King } 4138749af68SRussell King 4148749af68SRussell King return ret; 4158749af68SRussell King } 4168749af68SRussell King 4172ea83398SRussell King /* 4182ea83398SRussell King * Reprogram the system timer for at least the calculated time interval. 4192ea83398SRussell King * This function should be called from the idle thread with IRQs disabled, 4202ea83398SRussell King * immediately before sleeping. 4212ea83398SRussell King */ 4228749af68SRussell King void timer_dyn_reprogram(void) 4238749af68SRussell King { 4248749af68SRussell King struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 42569239749STony Lindgren unsigned long next, seq; 4268749af68SRussell King 42769239749STony Lindgren if (dyn_tick && (dyn_tick->state & DYN_TICK_ENABLED)) { 42869239749STony Lindgren next = next_timer_interrupt(); 42969239749STony Lindgren do { 43069239749STony Lindgren seq = read_seqbegin(&xtime_lock); 4318749af68SRussell King dyn_tick->reprogram(next_timer_interrupt() - jiffies); 43269239749STony Lindgren } while (read_seqretry(&xtime_lock, seq)); 4338749af68SRussell King } 4343618886fSBen Dooks } 4358749af68SRussell King 4368749af68SRussell King static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf) 4378749af68SRussell King { 4388749af68SRussell King return sprintf(buf, "%i\n", 4398749af68SRussell King (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1); 4408749af68SRussell King } 4418749af68SRussell King 4428749af68SRussell King static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf, 4438749af68SRussell King size_t count) 4448749af68SRussell King { 4458749af68SRussell King unsigned int enable = simple_strtoul(buf, NULL, 2); 4468749af68SRussell King 4478749af68SRussell King if (enable) 4488749af68SRussell King timer_dyn_tick_enable(); 4498749af68SRussell King else 4508749af68SRussell King timer_dyn_tick_disable(); 4518749af68SRussell King 4528749af68SRussell King return count; 4538749af68SRussell King } 4548749af68SRussell King static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick); 4558749af68SRussell King 4568749af68SRussell King /* 4578749af68SRussell King * dyntick=enable|disable 4588749af68SRussell King */ 4598749af68SRussell King static char dyntick_str[4] __initdata = ""; 4608749af68SRussell King 4618749af68SRussell King static int __init dyntick_setup(char *str) 4628749af68SRussell King { 4638749af68SRussell King if (str) 4648749af68SRussell King strlcpy(dyntick_str, str, sizeof(dyntick_str)); 4658749af68SRussell King return 1; 4668749af68SRussell King } 4678749af68SRussell King 4688749af68SRussell King __setup("dyntick=", dyntick_setup); 4698749af68SRussell King #endif 4708749af68SRussell King 4711da177e4SLinus Torvalds static int __init timer_init_sysfs(void) 4721da177e4SLinus Torvalds { 4731da177e4SLinus Torvalds int ret = sysdev_class_register(&timer_sysclass); 4741da177e4SLinus Torvalds if (ret == 0) { 4751da177e4SLinus Torvalds system_timer->dev.cls = &timer_sysclass; 4761da177e4SLinus Torvalds ret = sysdev_register(&system_timer->dev); 4771da177e4SLinus Torvalds } 4788749af68SRussell King 4798749af68SRussell King #ifdef CONFIG_NO_IDLE_HZ 4808749af68SRussell King if (ret == 0 && system_timer->dyn_tick) { 4818749af68SRussell King ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick); 4828749af68SRussell King 4838749af68SRussell King /* 4848749af68SRussell King * Turn on dynamic tick after calibrate delay 4858749af68SRussell King * for correct bogomips 4868749af68SRussell King */ 4878749af68SRussell King if (ret == 0 && dyntick_str[0] == 'e') 4888749af68SRussell King ret = timer_dyn_tick_enable(); 4898749af68SRussell King } 4908749af68SRussell King #endif 4918749af68SRussell King 4921da177e4SLinus Torvalds return ret; 4931da177e4SLinus Torvalds } 4941da177e4SLinus Torvalds 4951da177e4SLinus Torvalds device_initcall(timer_init_sysfs); 4961da177e4SLinus Torvalds 4971da177e4SLinus Torvalds void __init time_init(void) 4981da177e4SLinus Torvalds { 4991da177e4SLinus Torvalds if (system_timer->offset == NULL) 5001da177e4SLinus Torvalds system_timer->offset = dummy_gettimeoffset; 5011da177e4SLinus Torvalds system_timer->init(); 5021da177e4SLinus Torvalds } 5031da177e4SLinus Torvalds 504