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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/m68knommu/kernel/time.c
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/m68knommu/kernel/time.c')
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1 files changed, 198 insertions, 0 deletions
diff --git a/arch/m68knommu/kernel/time.c b/arch/m68knommu/kernel/time.c
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+/*
+ * linux/arch/m68knommu/kernel/time.c
+ *
+ * Copyright (C) 1991, 1992, 1995 Linus Torvalds
+ *
+ * This file contains the m68k-specific time handling details.
+ * Most of the stuff is located in the machine specific files.
+ *
+ * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
+ * "A Kernel Model for Precision Timekeeping" by Dave Mills
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/profile.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+
+#include <asm/machdep.h>
+#include <asm/io.h>
+
+#define TICK_SIZE (tick_nsec / 1000)
+
+u64 jiffies_64 = INITIAL_JIFFIES;
+
+EXPORT_SYMBOL(jiffies_64);
+
+extern unsigned long wall_jiffies;
+
+
+static inline int set_rtc_mmss(unsigned long nowtime)
+{
+ if (mach_set_clock_mmss)
+ return mach_set_clock_mmss (nowtime);
+ return -1;
+}
+
+/*
+ * timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ */
+static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
+{
+ /* last time the cmos clock got updated */
+ static long last_rtc_update=0;
+
+ /* may need to kick the hardware timer */
+ if (mach_tick)
+ mach_tick();
+
+ write_seqlock(&xtime_lock);
+
+ do_timer(regs);
+#ifndef CONFIG_SMP
+ update_process_times(user_mode(regs));
+#endif
+ if (current->pid)
+ profile_tick(CPU_PROFILING, regs);
+
+ /*
+ * If we have an externally synchronized Linux clock, then update
+ * CMOS 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 ((time_status & STA_UNSYNC) == 0 &&
+ 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 (set_rtc_mmss(xtime.tv_sec) == 0)
+ last_rtc_update = xtime.tv_sec;
+ else
+ last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
+ }
+#ifdef CONFIG_HEARTBEAT
+ /* use power LED as a heartbeat instead -- much more useful
+ for debugging -- based on the version for PReP by Cort */
+ /* acts like an actual heart beat -- ie thump-thump-pause... */
+ if (mach_heartbeat) {
+ static unsigned cnt = 0, period = 0, dist = 0;
+
+ if (cnt == 0 || cnt == dist)
+ mach_heartbeat( 1 );
+ else if (cnt == 7 || cnt == dist+7)
+ mach_heartbeat( 0 );
+
+ if (++cnt > period) {
+ cnt = 0;
+ /* The hyperbolic function below modifies the heartbeat period
+ * length in dependency of the current (5min) load. It goes
+ * through the points f(0)=126, f(1)=86, f(5)=51,
+ * f(inf)->30. */
+ period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
+ dist = period / 4;
+ }
+ }
+#endif /* CONFIG_HEARTBEAT */
+
+ write_sequnlock(&xtime_lock);
+ return(IRQ_HANDLED);
+}
+
+void time_init(void)
+{
+ unsigned int year, mon, day, hour, min, sec;
+
+ extern void arch_gettod(int *year, int *mon, int *day, int *hour,
+ int *min, int *sec);
+
+ arch_gettod(&year, &mon, &day, &hour, &min, &sec);
+
+ if ((year += 1900) < 1970)
+ year += 100;
+ xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
+ xtime.tv_nsec = 0;
+ wall_to_monotonic.tv_sec = -xtime.tv_sec;
+
+ mach_sched_init(timer_interrupt);
+}
+
+/*
+ * This version of gettimeofday has near microsecond resolution.
+ */
+void do_gettimeofday(struct timeval *tv)
+{
+ unsigned long flags;
+ unsigned long lost, seq;
+ unsigned long usec, sec;
+
+ do {
+ seq = read_seqbegin_irqsave(&xtime_lock, flags);
+ usec = mach_gettimeoffset ? mach_gettimeoffset() : 0;
+ lost = jiffies - wall_jiffies;
+ if (lost)
+ usec += lost * (1000000 / HZ);
+ sec = xtime.tv_sec;
+ usec += (xtime.tv_nsec / 1000);
+ } 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 the xtime.tv_usec
+ * correctly. However, the value in this location is
+ * is value at the last tick.
+ * Discover what correction gettimeofday
+ * would have done, and then undo it!
+ */
+ if (mach_gettimeoffset)
+ nsec -= (mach_gettimeoffset() * 1000);
+
+ 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);
+
+ time_adjust = 0; /* stop active adjtime() */
+ time_status |= STA_UNSYNC;
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_esterror = NTP_PHASE_LIMIT;
+ write_sequnlock_irq(&xtime_lock);
+ clock_was_set();
+ return 0;
+}
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+ return (unsigned long long)jiffies * (1000000000 / HZ);
+}
+
+EXPORT_SYMBOL(do_settimeofday);