linux/arch/sh/kernel/time.c
Paul Mundt bd156147eb sh: dyntick infrastructure.
This adds basic NO_IDLE_HZ support to the SH timer API so timers
are able to wire it up. Taken from the ARM version, as it fit in
to our API with very few changes needed.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-12-06 10:45:40 +09:00

338 lines
7.6 KiB
C

/*
* arch/sh/kernel/time.c
*
* Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
* Copyright (C) 2002 - 2006 Paul Mundt
* Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org>
*
* Some code taken from i386 version.
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/profile.h>
#include <asm/clock.h>
#include <asm/rtc.h>
#include <asm/timer.h>
#include <asm/kgdb.h>
struct sys_timer *sys_timer;
/* Move this somewhere more sensible.. */
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
/* Dummy RTC ops */
static void null_rtc_get_time(struct timespec *tv)
{
tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
tv->tv_nsec = 0;
}
static int null_rtc_set_time(const time_t secs)
{
return 0;
}
void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long __attribute__ ((weak)) sched_clock(void)
{
return (unsigned long long)jiffies * (1000000000 / HZ);
}
#ifndef CONFIG_GENERIC_TIME
void do_gettimeofday(struct timeval *tv)
{
unsigned long flags;
unsigned long seq;
unsigned long usec, sec;
do {
/*
* Turn off IRQs when grabbing xtime_lock, so that
* the sys_timer get_offset code doesn't have to handle it.
*/
seq = read_seqbegin_irqsave(&xtime_lock, flags);
usec = get_timer_offset();
sec = xtime.tv_sec;
usec += xtime.tv_nsec / NSEC_PER_USEC;
} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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
* made, and then undo it!
*/
nsec -= get_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 */
/* last time the RTC clock got updated */
static long last_rtc_update;
/*
* handle_timer_tick() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
void handle_timer_tick(void)
{
do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(get_irq_regs()));
#endif
if (current->pid)
profile_tick(CPU_PROFILING);
#ifdef CONFIG_HEARTBEAT
if (sh_mv.mv_heartbeat != NULL)
sh_mv.mv_heartbeat();
#endif
/*
* If we have an externally synchronized Linux clock, then update
* RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
* called as close as possible to 500 ms before the new second starts.
*/
if (ntp_synced() &&
xtime.tv_sec > last_rtc_update + 660 &&
(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
if (rtc_sh_set_time(xtime.tv_sec) == 0)
last_rtc_update = xtime.tv_sec;
else
/* do it again in 60s */
last_rtc_update = xtime.tv_sec - 600;
}
}
#ifdef CONFIG_PM
int timer_suspend(struct sys_device *dev, pm_message_t state)
{
struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
sys_timer->ops->stop();
return 0;
}
int timer_resume(struct sys_device *dev)
{
struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
sys_timer->ops->start();
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 = sys_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 = sys_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 = sys_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",
(sys_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)
return ret;
sys_timer->dev.cls = &timer_sysclass;
ret = sysdev_register(&sys_timer->dev);
#ifdef CONFIG_NO_IDLE_HZ
if (ret == 0 && sys_timer->dyn_tick) {
ret = sysdev_create_file(&sys_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 (*board_time_init)(void);
void __init time_init(void)
{
if (board_time_init)
board_time_init();
clk_init();
rtc_sh_get_time(&xtime);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
/*
* Find the timer to use as the system timer, it will be
* initialized for us.
*/
sys_timer = get_sys_timer();
printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
#ifdef CONFIG_NO_IDLE_HZ
if (sys_timer->dyn_tick)
spin_lock_init(&sys_timer->dyn_tick->lock);
#endif
#if defined(CONFIG_SH_KGDB)
/*
* Set up kgdb as requested. We do it here because the serial
* init uses the timer vars we just set up for figuring baud.
*/
kgdb_init();
#endif
}