]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - kernel/time/ntp.c
ntp: improve adjtimex frequency rounding
[linux-2.6-omap-h63xx.git] / kernel / time / ntp.c
index df9718bac8d01529b9bb6e57be951a64639ce297..ddb0465a6baab4d81d79ed7799f463e5f5d9cf55 100644 (file)
 
 #include <linux/mm.h>
 #include <linux/time.h>
-#include <linux/timer.h>
 #include <linux/timex.h>
 #include <linux/jiffies.h>
 #include <linux/hrtimer.h>
 #include <linux/capability.h>
 #include <linux/math64.h>
+#include <linux/clocksource.h>
+#include <linux/workqueue.h>
 #include <asm/timex.h>
 
 /*
@@ -26,6 +27,8 @@ unsigned long tick_nsec;                      /* ACTHZ period (nsec) */
 u64 tick_length;
 static u64 tick_length_base;
 
+static struct hrtimer leap_timer;
+
 #define MAX_TICKADJ            500             /* microsecs */
 #define MAX_TICKADJ_SCALED     (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
                                  NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
@@ -120,64 +123,70 @@ void ntp_clear(void)
 }
 
 /*
- * this routine handles the overflow of the microsecond field
- *
- * The tricky bits of code to handle the accurate clock support
- * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
- * They were originally developed for SUN and DEC kernels.
- * All the kudos should go to Dave for this stuff.
+ * Leap second processing. If in leap-insert state at the end of the
+ * day, the system clock is set back one second; if in leap-delete
+ * state, the system clock is set ahead one second.
  */
-void second_overflow(void)
+static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
 {
-       s64 time_adj;
+       enum hrtimer_restart res = HRTIMER_NORESTART;
 
-       /* Bump the maxerror field */
-       time_maxerror += MAXFREQ / NSEC_PER_USEC;
-       if (time_maxerror > NTP_PHASE_LIMIT) {
-               time_maxerror = NTP_PHASE_LIMIT;
-               time_status |= STA_UNSYNC;
-       }
+       write_seqlock_irq(&xtime_lock);
 
-       /*
-        * Leap second processing. If in leap-insert state at the end of the
-        * day, the system clock is set back one second; if in leap-delete
-        * state, the system clock is set ahead one second. The microtime()
-        * routine or external clock driver will insure that reported time is
-        * always monotonic. The ugly divides should be replaced.
-        */
        switch (time_state) {
        case TIME_OK:
-               if (time_status & STA_INS)
-                       time_state = TIME_INS;
-               else if (time_status & STA_DEL)
-                       time_state = TIME_DEL;
                break;
        case TIME_INS:
-               if (xtime.tv_sec % 86400 == 0) {
-                       xtime.tv_sec--;
-                       wall_to_monotonic.tv_sec++;
-                       time_state = TIME_OOP;
-                       printk(KERN_NOTICE "Clock: inserting leap second "
-                                       "23:59:60 UTC\n");
-               }
+               xtime.tv_sec--;
+               wall_to_monotonic.tv_sec++;
+               time_state = TIME_OOP;
+               printk(KERN_NOTICE "Clock: "
+                      "inserting leap second 23:59:60 UTC\n");
+               leap_timer.expires = ktime_add_ns(leap_timer.expires,
+                                                 NSEC_PER_SEC);
+               res = HRTIMER_RESTART;
                break;
        case TIME_DEL:
-               if ((xtime.tv_sec + 1) % 86400 == 0) {
-                       xtime.tv_sec++;
-                       time_tai--;
-                       wall_to_monotonic.tv_sec--;
-                       time_state = TIME_WAIT;
-                       printk(KERN_NOTICE "Clock: deleting leap second "
-                                       "23:59:59 UTC\n");
-               }
+               xtime.tv_sec++;
+               time_tai--;
+               wall_to_monotonic.tv_sec--;
+               time_state = TIME_WAIT;
+               printk(KERN_NOTICE "Clock: "
+                      "deleting leap second 23:59:59 UTC\n");
                break;
        case TIME_OOP:
                time_tai++;
                time_state = TIME_WAIT;
-               break;
+               /* fall through */
        case TIME_WAIT:
                if (!(time_status & (STA_INS | STA_DEL)))
                        time_state = TIME_OK;
+               break;
+       }
+       update_vsyscall(&xtime, clock);
+
+       write_sequnlock_irq(&xtime_lock);
+
+       return res;
+}
+
+/*
+ * this routine handles the overflow of the microsecond field
+ *
+ * The tricky bits of code to handle the accurate clock support
+ * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
+ * They were originally developed for SUN and DEC kernels.
+ * All the kudos should go to Dave for this stuff.
+ */
+void second_overflow(void)
+{
+       s64 time_adj;
+
+       /* Bump the maxerror field */
+       time_maxerror += MAXFREQ / NSEC_PER_USEC;
+       if (time_maxerror > NTP_PHASE_LIMIT) {
+               time_maxerror = NTP_PHASE_LIMIT;
+               time_status |= STA_UNSYNC;
        }
 
        /*
@@ -209,11 +218,11 @@ void second_overflow(void)
 /* Disable the cmos update - used by virtualization and embedded */
 int no_sync_cmos_clock  __read_mostly;
 
-static void sync_cmos_clock(unsigned long dummy);
+static void sync_cmos_clock(struct work_struct *work);
 
-static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
+static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
 
-static void sync_cmos_clock(unsigned long dummy)
+static void sync_cmos_clock(struct work_struct *work)
 {
        struct timespec now, next;
        int fail = 1;
@@ -249,13 +258,13 @@ static void sync_cmos_clock(unsigned long dummy)
                next.tv_sec++;
                next.tv_nsec -= NSEC_PER_SEC;
        }
-       mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
+       schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
 }
 
 static void notify_cmos_timer(void)
 {
        if (!no_sync_cmos_clock)
-               mod_timer(&sync_cmos_timer, jiffies + 1);
+               schedule_delayed_work(&sync_cmos_work, 0);
 }
 
 #else
@@ -268,34 +277,50 @@ static inline void notify_cmos_timer(void) { }
 int do_adjtimex(struct timex *txc)
 {
        struct timespec ts;
-       long save_adjust;
        int result;
 
-       /* In order to modify anything, you gotta be super-user! */
-       if (txc->modes && !capable(CAP_SYS_TIME))
-               return -EPERM;
-
-       /* Now we validate the data before disabling interrupts */
-
-       if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) {
+       /* Validate the data before disabling interrupts */
+       if (txc->modes & ADJ_ADJTIME) {
                /* singleshot must not be used with any other mode bits */
-               if (txc->modes & ~ADJ_OFFSET_SS_READ)
+               if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
                        return -EINVAL;
+               if (!(txc->modes & ADJ_OFFSET_READONLY) &&
+                   !capable(CAP_SYS_TIME))
+                       return -EPERM;
+       } else {
+               /* In order to modify anything, you gotta be super-user! */
+                if (txc->modes && !capable(CAP_SYS_TIME))
+                       return -EPERM;
+
+               /* if the quartz is off by more than 10% something is VERY wrong! */
+               if (txc->modes & ADJ_TICK &&
+                   (txc->tick <  900000/USER_HZ ||
+                    txc->tick > 1100000/USER_HZ))
+                               return -EINVAL;
+
+               if (txc->modes & ADJ_STATUS && time_state != TIME_OK)
+                       hrtimer_cancel(&leap_timer);
        }
 
-       /* if the quartz is off by more than 10% something is VERY wrong ! */
-       if (txc->modes & ADJ_TICK)
-               if (txc->tick <  900000/USER_HZ ||
-                   txc->tick > 1100000/USER_HZ)
-                       return -EINVAL;
+       getnstimeofday(&ts);
 
        write_seqlock_irq(&xtime_lock);
 
-       /* Save for later - semantics of adjtime is to return old value */
-       save_adjust = time_adjust;
-
        /* If there are input parameters, then process them */
+       if (txc->modes & ADJ_ADJTIME) {
+               long save_adjust = time_adjust;
+
+               if (!(txc->modes & ADJ_OFFSET_READONLY)) {
+                       /* adjtime() is independent from ntp_adjtime() */
+                       time_adjust = txc->offset;
+                       ntp_update_frequency();
+               }
+               txc->offset = save_adjust;
+               goto adj_done;
+       }
        if (txc->modes) {
+               long sec;
+
                if (txc->modes & ADJ_STATUS) {
                        if ((time_status & STA_PLL) &&
                            !(txc->status & STA_PLL)) {
@@ -305,6 +330,34 @@ int do_adjtimex(struct timex *txc)
                        /* only set allowed bits */
                        time_status &= STA_RONLY;
                        time_status |= txc->status & ~STA_RONLY;
+
+                       switch (time_state) {
+                       case TIME_OK:
+                       start_timer:
+                               sec = ts.tv_sec;
+                               if (time_status & STA_INS) {
+                                       time_state = TIME_INS;
+                                       sec += 86400 - sec % 86400;
+                                       hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
+                               } else if (time_status & STA_DEL) {
+                                       time_state = TIME_DEL;
+                                       sec += 86400 - (sec + 1) % 86400;
+                                       hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
+                               }
+                               break;
+                       case TIME_INS:
+                       case TIME_DEL:
+                               time_state = TIME_OK;
+                               goto start_timer;
+                               break;
+                       case TIME_WAIT:
+                               if (!(time_status & (STA_INS | STA_DEL)))
+                                       time_state = TIME_OK;
+                               break;
+                       case TIME_OOP:
+                               hrtimer_restart(&leap_timer);
+                               break;
+                       }
                }
 
                if (txc->modes & ADJ_NANO)
@@ -334,13 +387,8 @@ int do_adjtimex(struct timex *txc)
                if (txc->modes & ADJ_TAI && txc->constant > 0)
                        time_tai = txc->constant;
 
-               if (txc->modes & ADJ_OFFSET) {
-                       if (txc->modes == ADJ_OFFSET_SINGLESHOT)
-                               /* adjtime() is independent from ntp_adjtime() */
-                               time_adjust = txc->offset;
-                       else
-                               ntp_update_offset(txc->offset);
-               }
+               if (txc->modes & ADJ_OFFSET)
+                       ntp_update_offset(txc->offset);
                if (txc->modes & ADJ_TICK)
                        tick_usec = txc->tick;
 
@@ -348,22 +396,18 @@ int do_adjtimex(struct timex *txc)
                        ntp_update_frequency();
        }
 
+       txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
+                                 NTP_SCALE_SHIFT);
+       if (!(time_status & STA_NANO))
+               txc->offset /= NSEC_PER_USEC;
+
+adj_done:
        result = time_state;    /* mostly `TIME_OK' */
        if (time_status & (STA_UNSYNC|STA_CLOCKERR))
                result = TIME_ERROR;
 
-       if ((txc->modes == ADJ_OFFSET_SINGLESHOT) ||
-           (txc->modes == ADJ_OFFSET_SS_READ))
-               txc->offset = save_adjust;
-       else {
-               txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
-                                         NTP_SCALE_SHIFT);
-               if (!(time_status & STA_NANO))
-                       txc->offset /= NSEC_PER_USEC;
-       }
-       txc->freq          = shift_right((s32)(time_freq >> PPM_SCALE_INV_SHIFT) *
-                                        (s64)PPM_SCALE_INV,
-                                        NTP_SCALE_SHIFT);
+       txc->freq          = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
+                                        (s64)PPM_SCALE_INV, NTP_SCALE_SHIFT);
        txc->maxerror      = time_maxerror;
        txc->esterror      = time_esterror;
        txc->status        = time_status;
@@ -384,7 +428,6 @@ int do_adjtimex(struct timex *txc)
        txc->stbcnt        = 0;
        write_sequnlock_irq(&xtime_lock);
 
-       getnstimeofday(&ts);
        txc->time.tv_sec = ts.tv_sec;
        txc->time.tv_usec = ts.tv_nsec;
        if (!(time_status & STA_NANO))
@@ -402,3 +445,10 @@ static int __init ntp_tick_adj_setup(char *str)
 }
 
 __setup("ntp_tick_adj=", ntp_tick_adj_setup);
+
+void __init ntp_init(void)
+{
+       ntp_clear();
+       hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+       leap_timer.function = ntp_leap_second;
+}