![Paul Mundt](/assets/img/avatar_default.png)
This adds basic support for clockevents and clocksources, presently only implemented for TMU-based systems (which are the majority of SH-3 and SH-4 systems). The old NO_IDLE_HZ implementation is also dropped completely, the only users of this were on TMU-based systems anyways. More work needs to be done to generalize the TMU handling, in that the current implementation is rather tied to the notion of TMU0 and TMU1 utilization. Additionally, as more SH timers switch over to this scheme, we'll be able to gut most of the remaining system timer infrastructure that existed before. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
270 lines
6.3 KiB
C
270 lines
6.3 KiB
C
/*
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* arch/sh/kernel/time.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 - 2007 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 <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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do_timer(1);
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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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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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* 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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}
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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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set_kset_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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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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/*
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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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