linux/arch/arm/kernel/time.c

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/*
* 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_MODULE
EXPORT_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_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);
#ifndef CONFIG_GENERIC_TIME
static 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_TIMER
static 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_TIME
void do_gettimeofday(struct timeval *tv)
{
unsigned long flags;
unsigned long seq;
[PATCH] kill wall_jiffies With 2.6.18-rc4-mm2, now wall_jiffies will always be the same as jiffies. So we can kill wall_jiffies completely. This is just a cleanup and logically should not change any real behavior except for one thing: RTC updating code in (old) ppc and xtensa use a condition "jiffies - wall_jiffies == 1". This condition is never met so I suppose it is just a bug. I just remove that condition only instead of kill the whole "if" block. [heiko.carstens@de.ibm.com: s390 build fix and cleanup] Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 06:28:31 +00:00
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();
[PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem) Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390 timer interrupt handler with this change. Currently update_times() calculates ticks by "jiffies - wall_jiffies", but callers of do_timer() should know how many ticks to update. Passing ticks get rid of this redundant calculation. Also there are another redundancy pointed out by Martin Schwidefsky. This cleanup make a barrier added by 5aee405c662ca644980c184774277fc6d0769a84 needless. So this patch removes it. As a bonus, this cleanup make wall_jiffies can be removed easily, since now wall_jiffies is always synced with jiffies. (This patch does not really remove wall_jiffies. It would be another cleanup patch) Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Acked-by: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:00:32 +00:00
do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(get_irq_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)
{
#ifndef CONFIG_GENERIC_TIME
if (system_timer->offset == NULL)
system_timer->offset = dummy_gettimeoffset;
#endif
system_timer->init();
#ifdef CONFIG_NO_IDLE_HZ
if (system_timer->dyn_tick)
system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
#endif
}