![john stultz](/assets/img/avatar_default.png)
This patch cleans up a commonly repeated set of changes to the NTP state variables by adding two helper inline functions: ntp_clear(): Clears the ntp state variables ntp_synced(): Returns 1 if the system is synced with a time server. This was compile tested for alpha, arm, i386, x86-64, ppc64, s390, sparc, sparc64. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
241 lines
5.7 KiB
C
241 lines
5.7 KiB
C
/*
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* linux/arch/parisc/kernel/time.c
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*
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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* Modifications for ARM (C) 1994, 1995, 1996,1997 Russell King
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* Copyright (C) 1999 SuSE GmbH, (Philipp Rumpf, prumpf@tux.org)
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*
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* 1994-07-02 Alan Modra
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* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
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* 1998-12-20 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/profile.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include <asm/param.h>
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#include <asm/pdc.h>
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#include <asm/led.h>
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#include <linux/timex.h>
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u64 jiffies_64 = INITIAL_JIFFIES;
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EXPORT_SYMBOL(jiffies_64);
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/* xtime and wall_jiffies keep wall-clock time */
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extern unsigned long wall_jiffies;
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static long clocktick; /* timer cycles per tick */
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static long halftick;
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#ifdef CONFIG_SMP
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extern void smp_do_timer(struct pt_regs *regs);
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#endif
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irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
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{
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long now;
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long next_tick;
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int nticks;
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int cpu = smp_processor_id();
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profile_tick(CPU_PROFILING, regs);
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now = mfctl(16);
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/* initialize next_tick to time at last clocktick */
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next_tick = cpu_data[cpu].it_value;
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/* since time passes between the interrupt and the mfctl()
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* above, it is never true that last_tick + clocktick == now. If we
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* never miss a clocktick, we could set next_tick = last_tick + clocktick
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* but maybe we'll miss ticks, hence the loop.
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*
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* Variables are *signed*.
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*/
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nticks = 0;
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while((next_tick - now) < halftick) {
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next_tick += clocktick;
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nticks++;
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}
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mtctl(next_tick, 16);
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cpu_data[cpu].it_value = next_tick;
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while (nticks--) {
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#ifdef CONFIG_SMP
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smp_do_timer(regs);
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#else
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update_process_times(user_mode(regs));
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#endif
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if (cpu == 0) {
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write_seqlock(&xtime_lock);
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do_timer(regs);
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write_sequnlock(&xtime_lock);
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}
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}
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#ifdef CONFIG_CHASSIS_LCD_LED
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/* Only schedule the led tasklet on cpu 0, and only if it
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* is enabled.
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*/
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if (cpu == 0 && !atomic_read(&led_tasklet.count))
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tasklet_schedule(&led_tasklet);
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#endif
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/* check soft power switch status */
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if (cpu == 0 && !atomic_read(&power_tasklet.count))
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tasklet_schedule(&power_tasklet);
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return IRQ_HANDLED;
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}
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/*** converted from ia64 ***/
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/*
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* Return the number of micro-seconds that elapsed since the last
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* update to wall time (aka xtime aka wall_jiffies). The xtime_lock
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* must be at least read-locked when calling this routine.
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*/
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static inline unsigned long
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gettimeoffset (void)
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{
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#ifndef CONFIG_SMP
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/*
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* FIXME: This won't work on smp because jiffies are updated by cpu 0.
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* Once parisc-linux learns the cr16 difference between processors,
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* this could be made to work.
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*/
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long last_tick;
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long elapsed_cycles;
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/* it_value is the intended time of the next tick */
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last_tick = cpu_data[smp_processor_id()].it_value;
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/* Subtract one tick and account for possible difference between
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* when we expected the tick and when it actually arrived.
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* (aka wall vs real)
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*/
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last_tick -= clocktick * (jiffies - wall_jiffies + 1);
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elapsed_cycles = mfctl(16) - last_tick;
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/* the precision of this math could be improved */
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return elapsed_cycles / (PAGE0->mem_10msec / 10000);
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#else
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return 0;
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#endif
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}
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void
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do_gettimeofday (struct timeval *tv)
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{
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unsigned long flags, seq, usec, sec;
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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usec = gettimeoffset();
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sec = xtime.tv_sec;
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usec += (xtime.tv_nsec / 1000);
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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
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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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/*
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* This is revolting. We need to set "xtime"
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* correctly. However, the value in this location is
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* the value at the most recent update of wall time.
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* Discover what correction gettimeofday would have
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* done, and then undo it!
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*/
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nsec -= gettimeoffset() * 1000;
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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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}
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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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/*
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* XXX: We can do better than this.
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* Returns nanoseconds
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*/
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unsigned long long sched_clock(void)
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{
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return (unsigned long long)jiffies * (1000000000 / HZ);
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}
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void __init time_init(void)
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{
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unsigned long next_tick;
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static struct pdc_tod tod_data;
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clocktick = (100 * PAGE0->mem_10msec) / HZ;
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halftick = clocktick / 2;
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/* Setup clock interrupt timing */
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next_tick = mfctl(16);
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next_tick += clocktick;
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cpu_data[smp_processor_id()].it_value = next_tick;
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/* kick off Itimer (CR16) */
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mtctl(next_tick, 16);
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if(pdc_tod_read(&tod_data) == 0) {
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write_seqlock_irq(&xtime_lock);
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xtime.tv_sec = tod_data.tod_sec;
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xtime.tv_nsec = tod_data.tod_usec * 1000;
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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write_sequnlock_irq(&xtime_lock);
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} else {
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printk(KERN_ERR "Error reading tod clock\n");
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xtime.tv_sec = 0;
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xtime.tv_nsec = 0;
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}
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}
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