[XTENSA] Fix timer instabilities.
The timer code could have missed a tick. Signed-off-by: Chris Zankel <chris@zankel.net>
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bc671aa983
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2b8aea74e7
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@ -32,12 +32,20 @@ EXPORT_SYMBOL(rtc_lock);
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#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
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#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
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unsigned long ccount_per_jiffy; /* per 1/HZ */
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unsigned long ccount_per_jiffy; /* per 1/HZ */
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unsigned long ccount_nsec; /* nsec per ccount increment */
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unsigned long nsec_per_ccount; /* nsec per ccount increment */
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#endif
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#endif
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unsigned int last_ccount_stamp;
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static long last_rtc_update = 0;
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static long last_rtc_update = 0;
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/*
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* Scheduler clock - returns current tim in nanosec units.
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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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static irqreturn_t timer_interrupt(int irq, void *dev_id);
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static irqreturn_t timer_interrupt(int irq, void *dev_id);
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static struct irqaction timer_irqaction = {
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static struct irqaction timer_irqaction = {
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.handler = timer_interrupt,
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.handler = timer_interrupt,
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@ -69,7 +77,6 @@ void __init time_init(void)
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xtime.tv_nsec = 0;
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xtime.tv_nsec = 0;
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last_rtc_update = xtime.tv_sec = sec_n;
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last_rtc_update = xtime.tv_sec = sec_n;
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last_ccount_stamp = get_ccount();
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set_normalized_timespec(&wall_to_monotonic,
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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-xtime.tv_sec, -xtime.tv_nsec);
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@ -85,7 +92,7 @@ int do_settimeofday(struct timespec *tv)
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{
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{
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time_t wtm_sec, sec = tv->tv_sec;
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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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long wtm_nsec, nsec = tv->tv_nsec;
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unsigned long ccount;
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unsigned long delta;
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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return -EINVAL;
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@ -97,8 +104,10 @@ int do_settimeofday(struct timespec *tv)
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* wall time. Discover what correction gettimeofday() would have
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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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* made, and then undo it!
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*/
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*/
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ccount = get_ccount();
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nsec -= (ccount - last_ccount_stamp) * CCOUNT_NSEC;
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delta = CCOUNT_PER_JIFFY;
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delta += get_ccount() - get_linux_timer();
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nsec -= delta * NSEC_PER_CCOUNT;
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wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
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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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wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
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@ -117,17 +126,21 @@ EXPORT_SYMBOL(do_settimeofday);
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void do_gettimeofday(struct timeval *tv)
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void do_gettimeofday(struct timeval *tv)
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{
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{
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unsigned long flags;
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unsigned long flags;
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unsigned long sec, usec, delta, seq;
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unsigned long volatile sec, usec, delta, seq;
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do {
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do {
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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seq = read_seqbegin_irqsave(&xtime_lock, flags);
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delta = get_ccount() - last_ccount_stamp;
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sec = xtime.tv_sec;
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sec = xtime.tv_sec;
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usec = (xtime.tv_nsec / NSEC_PER_USEC);
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usec = (xtime.tv_nsec / NSEC_PER_USEC);
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delta = get_linux_timer() - get_ccount();
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
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usec += (delta * CCOUNT_NSEC) / NSEC_PER_USEC;
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usec += (((unsigned long) CCOUNT_PER_JIFFY - delta)
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* (unsigned long) NSEC_PER_CCOUNT) / NSEC_PER_USEC;
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for (; usec >= 1000000; sec++, usec -= 1000000)
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for (; usec >= 1000000; sec++, usec -= 1000000)
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;
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;
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@ -158,9 +171,12 @@ again:
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write_seqlock(&xtime_lock);
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write_seqlock(&xtime_lock);
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last_ccount_stamp = next;
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do_timer(1); /* Linux handler in kernel/timer.c */
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/* Note that writing CCOMPARE clears the interrupt. */
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next += CCOUNT_PER_JIFFY;
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next += CCOUNT_PER_JIFFY;
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do_timer (1); /* Linux handler in kernel/timer.c */
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set_linux_timer(next);
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if (ntp_synced() &&
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if (ntp_synced() &&
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xtime.tv_sec - last_rtc_update >= 659 &&
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xtime.tv_sec - last_rtc_update >= 659 &&
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@ -175,19 +191,15 @@ again:
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write_sequnlock(&xtime_lock);
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write_sequnlock(&xtime_lock);
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}
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}
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/* NOTE: writing CCOMPAREn clears the interrupt. */
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/* Allow platform to do something useful (Wdog). */
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set_linux_timer (next);
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platform_heartbeat();
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/* Make sure we didn't miss any tick... */
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/* Make sure we didn't miss any tick... */
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if ((signed long)(get_ccount() - next) > 0)
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if ((signed long)(get_ccount() - next) > 0)
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goto again;
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goto again;
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/* Allow platform to do something useful (Wdog). */
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platform_heartbeat();
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return IRQ_HANDLED;
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return IRQ_HANDLED;
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}
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}
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@ -41,10 +41,10 @@
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extern unsigned long ccount_per_jiffy;
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extern unsigned long ccount_per_jiffy;
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extern unsigned long ccount_nsec;
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extern unsigned long ccount_nsec;
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#define CCOUNT_PER_JIFFY ccount_per_jiffy
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#define CCOUNT_PER_JIFFY ccount_per_jiffy
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#define CCOUNT_NSEC ccount_nsec
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#define NSEC_PER_CCOUNT ccount_nsec
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#else
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#else
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#define CCOUNT_PER_JIFFY (CONFIG_XTENSA_CPU_CLOCK*(1000000UL/HZ))
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#define CCOUNT_PER_JIFFY (CONFIG_XTENSA_CPU_CLOCK*(1000000UL/HZ))
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#define CCOUNT_NSEC (1000000000UL / CONFIG_XTENSA_CPU_CLOCK)
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#define NSEC_PER_CCOUNT (1000UL / CONFIG_XTENSA_CPU_CLOCK)
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#endif
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#endif
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