[PATCH] NTP: Move all the NTP related code to ntp.c

Move all the NTP related code to ntp.c

[akpm@osdl.org: cleanups, build fix]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 390 insertions, 1 deletions

diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index e1dfd8e86cce..61a3907d16fb 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1 +1 @@
-obj-y += clocksource.o jiffies.o
+obj-y += ntp.o clocksource.o jiffies.o
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
new file mode 100644
index 000000000000..8ccce15b4b23
--- /dev/null
+++ b/kernel/time/ntp.c
@@ -0,0 +1,389 @@
+/*
+ * linux/kernel/time/ntp.c
+ *
+ * NTP state machine interfaces and logic.
+ *
+ * This code was mainly moved from kernel/timer.c and kernel/time.c
+ * Please see those files for relevant copyright info and historical
+ * changelogs.
+ */
+
+#include <linux/mm.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+
+#include <asm/div64.h>
+#include <asm/timex.h>
+
+/* Don't completely fail for HZ > 500.  */
+int tickadj = 500/HZ ? : 1;             /* microsecs */
+
+/*
+ * phase-lock loop variables
+ */
+/* TIME_ERROR prevents overwriting the CMOS clock */
+int time_state = TIME_OK;               /* clock synchronization status */
+int time_status = STA_UNSYNC;           /* clock status bits            */
+long time_offset;                       /* time adjustment (us)         */
+long time_constant = 2;                 /* pll time constant            */
+long time_tolerance = MAXFREQ;          /* frequency tolerance (ppm)    */
+long time_precision = 1;                /* clock precision (us)         */
+long time_maxerror = NTP_PHASE_LIMIT;   /* maximum error (us)           */
+long time_esterror = NTP_PHASE_LIMIT;   /* estimated error (us)         */
+long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
+                                        /* frequency offset (scaled ppm)*/
+static long time_adj;                   /* tick adjust (scaled 1 / HZ)  */
+long time_reftime;                      /* time at last adjustment (s)  */
+long time_adjust;
+long time_next_adjust;
+
+/*
+ * 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)
+{
+        long ltemp;
+
+        /* Bump the maxerror field */
+        time_maxerror += time_tolerance >> SHIFT_USEC;
+        if (time_maxerror > NTP_PHASE_LIMIT) {
+                time_maxerror = NTP_PHASE_LIMIT;
+                time_status |= STA_UNSYNC;
+        }
+
+        /*
+         * 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++;
+                        /*
+                         * The timer interpolator will make time change
+                         * gradually instead of an immediate jump by one second
+                         */
+                        time_interpolator_update(-NSEC_PER_SEC);
+                        time_state = TIME_OOP;
+                        clock_was_set();
+                        printk(KERN_NOTICE "Clock: inserting leap second "
+                                        "23:59:60 UTC\n");
+                }
+                break;
+        case TIME_DEL:
+                if ((xtime.tv_sec + 1) % 86400 == 0) {
+                        xtime.tv_sec++;
+                        wall_to_monotonic.tv_sec--;
+                        /*
+                         * Use of time interpolator for a gradual change of
+                         * time
+                         */
+                        time_interpolator_update(NSEC_PER_SEC);
+                        time_state = TIME_WAIT;
+                        clock_was_set();
+                        printk(KERN_NOTICE "Clock: deleting leap second "
+                                        "23:59:59 UTC\n");
+                }
+                break;
+        case TIME_OOP:
+                time_state = TIME_WAIT;
+                break;
+        case TIME_WAIT:
+                if (!(time_status & (STA_INS | STA_DEL)))
+                time_state = TIME_OK;
+        }
+
+        /*
+         * Compute the phase adjustment for the next second. In PLL mode, the
+         * offset is reduced by a fixed factor times the time constant. In FLL
+         * mode the offset is used directly. In either mode, the maximum phase
+         * adjustment for each second is clamped so as to spread the adjustment
+         * over not more than the number of seconds between updates.
+         */
+        ltemp = time_offset;
+        if (!(time_status & STA_FLL))
+                ltemp = shift_right(ltemp, SHIFT_KG + time_constant);
+        ltemp = min(ltemp, (MAXPHASE / MINSEC) << SHIFT_UPDATE);
+        ltemp = max(ltemp, -(MAXPHASE / MINSEC) << SHIFT_UPDATE);
+        time_offset -= ltemp;
+        time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+
+        /*
+         * Compute the frequency estimate and additional phase adjustment due
+         * to frequency error for the next second.
+         */
+        ltemp = time_freq;
+        time_adj += shift_right(ltemp,(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
+
+#if HZ == 100
+        /*
+         * Compensate for (HZ==100) != (1 << SHIFT_HZ).  Add 25% and 3.125% to
+         * get 128.125; => only 0.125% error (p. 14)
+         */
+        time_adj += shift_right(time_adj, 2) + shift_right(time_adj, 5);
+#endif
+#if HZ == 250
+        /*
+         * Compensate for (HZ==250) != (1 << SHIFT_HZ).  Add 1.5625% and
+         * 0.78125% to get 255.85938; => only 0.05% error (p. 14)
+         */
+        time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
+#endif
+#if HZ == 1000
+        /*
+         * Compensate for (HZ==1000) != (1 << SHIFT_HZ).  Add 1.5625% and
+         * 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
+         */
+        time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
+#endif
+}
+
+/*
+ * Returns how many microseconds we need to add to xtime this tick
+ * in doing an adjustment requested with adjtime.
+ */
+static long adjtime_adjustment(void)
+{
+        long time_adjust_step;
+
+        time_adjust_step = time_adjust;
+        if (time_adjust_step) {
+                /*
+                 * We are doing an adjtime thing.  Prepare time_adjust_step to
+                 * be within bounds.  Note that a positive time_adjust means we
+                 * want the clock to run faster.
+                 *
+                 * Limit the amount of the step to be in the range
+                 * -tickadj .. +tickadj
+                 */
+                time_adjust_step = min(time_adjust_step, (long)tickadj);
+                time_adjust_step = max(time_adjust_step, (long)-tickadj);
+        }
+        return time_adjust_step;
+}
+
+/* in the NTP reference this is called "hardclock()" */
+void update_ntp_one_tick(void)
+{
+        long time_adjust_step;
+
+        time_adjust_step = adjtime_adjustment();
+        if (time_adjust_step)
+                /* Reduce by this step the amount of time left  */
+                time_adjust -= time_adjust_step;
+
+        /* Changes by adjtime() do not take effect till next tick. */
+        if (time_next_adjust != 0) {
+                time_adjust = time_next_adjust;
+                time_next_adjust = 0;
+        }
+}
+
+/*
+ * Return how long ticks are at the moment, that is, how much time
+ * update_wall_time_one_tick will add to xtime next time we call it
+ * (assuming no calls to do_adjtimex in the meantime).
+ * The return value is in fixed-point nanoseconds shifted by the
+ * specified number of bits to the right of the binary point.
+ * This function has no side-effects.
+ */
+u64 current_tick_length(void)
+{
+        long delta_nsec;
+        u64 ret;
+
+        /* calculate the finest interval NTP will allow.
+         *    ie: nanosecond value shifted by (SHIFT_SCALE - 10)
+         */
+        delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
+        ret = (u64)delta_nsec << TICK_LENGTH_SHIFT;
+        ret += (s64)time_adj << (TICK_LENGTH_SHIFT - (SHIFT_SCALE - 10));
+
+        return ret;
+}
+
+
+void __attribute__ ((weak)) notify_arch_cmos_timer(void)
+{
+        return;
+}
+
+/* adjtimex mainly allows reading (and writing, if superuser) of
+ * kernel time-keeping variables. used by xntpd.
+ */
+int do_adjtimex(struct timex *txc)
+{
+        long ltemp, mtemp, 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)
+          /* singleshot must not be used with any other mode bits */
+                if (txc->modes != ADJ_OFFSET_SINGLESHOT)
+                        return -EINVAL;
+
+        if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
+          /* adjustment Offset limited to +- .512 seconds */
+                if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
+                        return -EINVAL;
+
+        /* 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;
+
+        write_seqlock_irq(&xtime_lock);
+        result = time_state;    /* mostly `TIME_OK' */
+
+        /* Save for later - semantics of adjtime is to return old value */
+        save_adjust = time_next_adjust ? time_next_adjust : time_adjust;
+
+#if 0   /* STA_CLOCKERR is never set yet */
+        time_status &= ~STA_CLOCKERR;           /* reset STA_CLOCKERR */
+#endif
+        /* If there are input parameters, then process them */
+        if (txc->modes)
+        {
+            if (txc->modes & ADJ_STATUS)        /* only set allowed bits */
+                time_status =  (txc->status & ~STA_RONLY) |
+                              (time_status & STA_RONLY);
+
+            if (txc->modes & ADJ_FREQUENCY) {   /* p. 22 */
+                if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
+                    result = -EINVAL;
+                    goto leave;
+                }
+                time_freq = txc->freq;
+            }
+
+            if (txc->modes & ADJ_MAXERROR) {
+                if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
+                    result = -EINVAL;
+                    goto leave;
+                }
+                time_maxerror = txc->maxerror;
+            }
+
+            if (txc->modes & ADJ_ESTERROR) {
+                if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
+                    result = -EINVAL;
+                    goto leave;
+                }
+                time_esterror = txc->esterror;
+            }
+
+            if (txc->modes & ADJ_TIMECONST) {   /* p. 24 */
+                if (txc->constant < 0) {        /* NTP v4 uses values > 6 */
+                    result = -EINVAL;
+                    goto leave;
+                }
+                time_constant = txc->constant;
+            }
+
+            if (txc->modes & ADJ_OFFSET) {      /* values checked earlier */
+                if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
+                    /* adjtime() is independent from ntp_adjtime() */
+                    if ((time_next_adjust = txc->offset) == 0)
+                         time_adjust = 0;
+                }
+                else if (time_status & STA_PLL) {
+                    ltemp = txc->offset;
+
+                    /*
+                     * Scale the phase adjustment and
+                     * clamp to the operating range.
+                     */
+                    if (ltemp > MAXPHASE)
+                        time_offset = MAXPHASE << SHIFT_UPDATE;
+                    else if (ltemp < -MAXPHASE)
+                        time_offset = -(MAXPHASE << SHIFT_UPDATE);
+                    else
+                        time_offset = ltemp << SHIFT_UPDATE;
+
+                    /*
+                     * Select whether the frequency is to be controlled
+                     * and in which mode (PLL or FLL). Clamp to the operating
+                     * range. Ugly multiply/divide should be replaced someday.
+                     */
+
+                    if (time_status & STA_FREQHOLD || time_reftime == 0)
+                        time_reftime = xtime.tv_sec;
+                    mtemp = xtime.tv_sec - time_reftime;
+                    time_reftime = xtime.tv_sec;
+                    if (time_status & STA_FLL) {
+                        if (mtemp >= MINSEC) {
+                            ltemp = (time_offset / mtemp) << (SHIFT_USEC -
+                                                              SHIFT_UPDATE);
+                            time_freq += shift_right(ltemp, SHIFT_KH);
+                        } else /* calibration interval too short (p. 12) */
+                                result = TIME_ERROR;
+                    } else {    /* PLL mode */
+                        if (mtemp < MAXSEC) {
+                            ltemp *= mtemp;
+                            time_freq += shift_right(ltemp,(time_constant +
+                                                       time_constant +
+                                                       SHIFT_KF - SHIFT_USEC));
+                        } else /* calibration interval too long (p. 12) */
+                                result = TIME_ERROR;
+                    }
+                    time_freq = min(time_freq, time_tolerance);
+                    time_freq = max(time_freq, -time_tolerance);
+                } /* STA_PLL */
+            } /* txc->modes & ADJ_OFFSET */
+            if (txc->modes & ADJ_TICK) {
+                tick_usec = txc->tick;
+                tick_nsec = TICK_USEC_TO_NSEC(tick_usec);
+            }
+        } /* txc->modes */
+leave:  if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
+                result = TIME_ERROR;
+
+        if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
+            txc->offset    = save_adjust;
+        else {
+            txc->offset = shift_right(time_offset, SHIFT_UPDATE);
+        }
+        txc->freq          = time_freq;
+        txc->maxerror      = time_maxerror;
+        txc->esterror      = time_esterror;
+        txc->status        = time_status;
+        txc->constant      = time_constant;
+        txc->precision     = time_precision;
+        txc->tolerance     = time_tolerance;
+        txc->tick          = tick_usec;
+
+        /* PPS is not implemented, so these are zero */
+        txc->ppsfreq       = 0;
+        txc->jitter        = 0;
+        txc->shift         = 0;
+        txc->stabil        = 0;
+        txc->jitcnt        = 0;
+        txc->calcnt        = 0;
+        txc->errcnt        = 0;
+        txc->stbcnt        = 0;
+        write_sequnlock_irq(&xtime_lock);
+        do_gettimeofday(&txc->time);
+        notify_arch_cmos_timer();
+        return(result);
+}