287 lines
6.8 KiB
C
287 lines
6.8 KiB
C
/*
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* arch/sh/kernel/time_32.c
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*
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* Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
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* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
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* Copyright (C) 2002 - 2008 Paul Mundt
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* Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org>
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*
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* Some code taken from i386 version.
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/profile.h>
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#include <linux/timex.h>
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#include <linux/sched.h>
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#include <linux/clockchips.h>
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#include <linux/mc146818rtc.h> /* for rtc_lock */
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#include <linux/smp.h>
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#include <asm/clock.h>
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#include <asm/rtc.h>
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#include <asm/timer.h>
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#include <asm/kgdb.h>
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struct sys_timer *sys_timer;
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/* Move this somewhere more sensible.. */
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL(rtc_lock);
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/* Dummy RTC ops */
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static void null_rtc_get_time(struct timespec *tv)
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{
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tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
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tv->tv_nsec = 0;
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}
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static int null_rtc_set_time(const time_t secs)
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{
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return 0;
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}
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/*
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* Null high precision timer functions for systems lacking one.
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*/
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static cycle_t null_hpt_read(void)
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{
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return 0;
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}
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void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
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int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
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#ifndef CONFIG_GENERIC_TIME
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void do_gettimeofday(struct timeval *tv)
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{
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unsigned long flags;
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unsigned long seq;
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unsigned long usec, sec;
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do {
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/*
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* Turn off IRQs when grabbing xtime_lock, so that
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* the sys_timer get_offset code doesn't have to handle it.
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*/
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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usec = get_timer_offset();
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sec = xtime.tv_sec;
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usec += xtime.tv_nsec / NSEC_PER_USEC;
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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while (usec >= 1000000) {
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usec -= 1000000;
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sec++;
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}
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tv->tv_sec = sec;
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tv->tv_usec = usec;
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}
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EXPORT_SYMBOL(do_gettimeofday);
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int do_settimeofday(struct timespec *tv)
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{
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time_t wtm_sec, sec = tv->tv_sec;
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long wtm_nsec, nsec = tv->tv_nsec;
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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write_seqlock_irq(&xtime_lock);
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/*
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* This is revolting. We need to set "xtime" correctly. However, the
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* value in this location is the value at the most recent update of
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* wall time. Discover what correction gettimeofday() would have
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* made, and then undo it!
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*/
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nsec -= get_timer_offset() * NSEC_PER_USEC;
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wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
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wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
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set_normalized_timespec(&xtime, sec, nsec);
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set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
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ntp_clear();
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write_sequnlock_irq(&xtime_lock);
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clock_was_set();
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return 0;
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}
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EXPORT_SYMBOL(do_settimeofday);
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#endif /* !CONFIG_GENERIC_TIME */
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#ifndef CONFIG_GENERIC_CLOCKEVENTS
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/* last time the RTC clock got updated */
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static long last_rtc_update;
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/*
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* handle_timer_tick() needs to keep up the real-time clock,
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* as well as call the "do_timer()" routine every clocktick
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*/
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void handle_timer_tick(void)
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{
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if (current->pid)
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profile_tick(CPU_PROFILING);
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#ifdef CONFIG_HEARTBEAT
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if (sh_mv.mv_heartbeat != NULL)
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sh_mv.mv_heartbeat();
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#endif
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/*
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* Here we are in the timer irq handler. We just have irqs locally
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* disabled but we don't know if the timer_bh is running on the other
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* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
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* the irq version of write_lock because as just said we have irq
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* locally disabled. -arca
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*/
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write_seqlock(&xtime_lock);
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do_timer(1);
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/*
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* If we have an externally synchronized Linux clock, then update
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* RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
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* called as close as possible to 500 ms before the new second starts.
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*/
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if (ntp_synced() &&
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xtime.tv_sec > last_rtc_update + 660 &&
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(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
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(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
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if (rtc_sh_set_time(xtime.tv_sec) == 0)
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last_rtc_update = xtime.tv_sec;
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else
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/* do it again in 60s */
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last_rtc_update = xtime.tv_sec - 600;
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}
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write_sequnlock(&xtime_lock);
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#ifndef CONFIG_SMP
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update_process_times(user_mode(get_irq_regs()));
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#endif
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}
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#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
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#ifdef CONFIG_PM
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int timer_suspend(struct sys_device *dev, pm_message_t state)
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{
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struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
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sys_timer->ops->stop();
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return 0;
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}
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int timer_resume(struct sys_device *dev)
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{
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struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
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sys_timer->ops->start();
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return 0;
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}
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#else
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#define timer_suspend NULL
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#define timer_resume NULL
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#endif
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static struct sysdev_class timer_sysclass = {
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.name = "timer",
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.suspend = timer_suspend,
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.resume = timer_resume,
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};
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static int __init timer_init_sysfs(void)
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{
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int ret = sysdev_class_register(&timer_sysclass);
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if (ret != 0)
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return ret;
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sys_timer->dev.cls = &timer_sysclass;
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return sysdev_register(&sys_timer->dev);
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}
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device_initcall(timer_init_sysfs);
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void (*board_time_init)(void);
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/*
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* Shamelessly based on the MIPS and Sparc64 work.
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*/
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static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
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unsigned long sh_hpt_frequency = 0;
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#define NSEC_PER_CYC_SHIFT 10
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static struct clocksource clocksource_sh = {
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.name = "SuperH",
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.rating = 200,
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.mask = CLOCKSOURCE_MASK(32),
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.read = null_hpt_read,
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.shift = 16,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static void __init init_sh_clocksource(void)
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{
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if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
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return;
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clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
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clocksource_sh.shift);
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timer_ticks_per_nsec_quotient =
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clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);
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clocksource_register(&clocksource_sh);
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}
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#ifdef CONFIG_GENERIC_TIME
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unsigned long long sched_clock(void)
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{
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unsigned long long ticks = clocksource_sh.read();
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return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
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}
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#endif
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void __init time_init(void)
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{
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if (board_time_init)
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board_time_init();
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clk_init();
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rtc_sh_get_time(&xtime);
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
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local_timer_setup(smp_processor_id());
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#endif
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/*
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* Find the timer to use as the system timer, it will be
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* initialized for us.
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*/
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sys_timer = get_sys_timer();
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printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
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if (sys_timer->ops->read)
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clocksource_sh.read = sys_timer->ops->read;
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init_sh_clocksource();
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if (sh_hpt_frequency)
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printk("Using %lu.%03lu MHz high precision timer.\n",
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((sh_hpt_frequency + 500) / 1000) / 1000,
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((sh_hpt_frequency + 500) / 1000) % 1000);
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#if defined(CONFIG_SH_KGDB)
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/*
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* Set up kgdb as requested. We do it here because the serial
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* init uses the timer vars we just set up for figuring baud.
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*/
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kgdb_init();
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#endif
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}
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