3 files changed, 21 insertions, 22 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 3b26fbd6bec9..c146af995854 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -1007,8 +1007,6 @@ void __init time_init(void)
         vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
         vdso_data->tb_to_xs = tb_to_xs;
 
-        time_freq = 0;
-
         write_sequnlock_irqrestore(&xtime_lock, flags);
 
         /* Register the clocksource, if we're not running on iSeries */
diff --git a/include/linux/timex.h b/include/linux/timex.h
index 3c49d173bf39..48c3376dce71 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -86,11 +86,14 @@
  */
 #define SHIFT_UPDATE (SHIFT_HZ + 1) /* time offset scale (shift) */
 #define SHIFT_USEC 16           /* frequency offset scale (shift) */
-#define SHIFT_NSEC 12           /* kernel frequency offset scale */
+#define PPM_SCALE (NSEC_PER_USEC << (TICK_LENGTH_SHIFT - SHIFT_USEC))
+#define PPM_SCALE_INV_SHIFT 20
+#define PPM_SCALE_INV ((1ll << (PPM_SCALE_INV_SHIFT + TICK_LENGTH_SHIFT)) / \
+                       PPM_SCALE + 1)
 
 #define MAXPHASE 512000L        /* max phase error (us) */
-#define MAXFREQ (512L << SHIFT_USEC)  /* max frequency error (ppm) */
-#define MAXFREQ_NSEC (512000L << SHIFT_NSEC) /* max frequency error (ppb) */
+#define MAXFREQ 500000          /* max frequency error (ns/s) */
+#define MAXFREQ_SCALED ((s64)MAXFREQ << TICK_LENGTH_SHIFT)
 #define MINSEC 256              /* min interval between updates (s) */
 #define MAXSEC 2048             /* max interval between updates (s) */
 #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */
@@ -209,8 +212,6 @@ extern int time_status;		/* clock synchronization status bits */
 extern long time_maxerror;      /* maximum error */
 extern long time_esterror;      /* estimated error */
 
-extern long time_freq;          /* frequency offset (scaled ppm) */
-
 extern long time_adjust;        /* The amount of adjtime left */
 
 extern void ntp_clear(void);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 3fc81066d7f1..c6ae0c249891 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -39,7 +39,7 @@ static s64 time_offset;			/* time adjustment (ns)		*/
 static long time_constant = 2;          /* pll time constant            */
 long time_maxerror = NTP_PHASE_LIMIT;   /* maximum error (us)           */
 long time_esterror = NTP_PHASE_LIMIT;   /* estimated error (us)         */
-long time_freq;                         /* frequency offset (scaled ppm)*/
+static s64 time_freq;                   /* frequency offset (scaled ns/s)*/
 static long time_reftime;               /* time at last adjustment (s)  */
 long time_adjust;
 static long ntp_tick_adj;
@@ -49,7 +49,7 @@ static void ntp_update_frequency(void)
         u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
                                 << TICK_LENGTH_SHIFT;
         second_length += (s64)ntp_tick_adj << TICK_LENGTH_SHIFT;
-        second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
+        second_length += time_freq;
 
         tick_length_base = second_length;
 
@@ -86,16 +86,16 @@ static void ntp_update_offset(long offset)
         time_reftime = xtime.tv_sec;
 
         freq_adj = time_offset * mtemp;
-        freq_adj = shift_right(freq_adj, time_constant * 2 +
-                           (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
+        freq_adj <<= TICK_LENGTH_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant);
         time_status &= ~STA_MODE;
         if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
-                freq_adj += div_s64(time_offset << (SHIFT_NSEC - SHIFT_FLL), mtemp);
+                freq_adj += div_s64(time_offset << (TICK_LENGTH_SHIFT - SHIFT_FLL),
+                                    mtemp);
                 time_status |= STA_MODE;
         }
         freq_adj += time_freq;
-        freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
-        time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
+        freq_adj = min(freq_adj, MAXFREQ_SCALED);
+        time_freq = max(freq_adj, -MAXFREQ_SCALED);
         time_offset = div_s64(time_offset, NTP_INTERVAL_FREQ);
         time_offset <<= SHIFT_UPDATE;
 }
@@ -131,7 +131,7 @@ void second_overflow(void)
         long time_adj;
 
         /* Bump the maxerror field */
-        time_maxerror += MAXFREQ >> SHIFT_USEC;
+        time_maxerror += MAXFREQ / NSEC_PER_USEC;
         if (time_maxerror > NTP_PHASE_LIMIT) {
                 time_maxerror = NTP_PHASE_LIMIT;
                 time_status |= STA_UNSYNC;
@@ -323,10 +323,9 @@ int do_adjtimex(struct timex *txc)
                         time_status &= ~STA_NANO;
 
                 if (txc->modes & ADJ_FREQUENCY) {
-                        time_freq = min(txc->freq, MAXFREQ);
-                        time_freq = min(time_freq, -MAXFREQ);
-                        time_freq = ((s64)time_freq * NSEC_PER_USEC)
-                                        >> (SHIFT_USEC - SHIFT_NSEC);
+                        time_freq = (s64)txc->freq * PPM_SCALE;
+                        time_freq = min(time_freq, MAXFREQ_SCALED);
+                        time_freq = max(time_freq, -MAXFREQ_SCALED);
                 }
 
                 if (txc->modes & ADJ_MAXERROR)
@@ -369,14 +368,15 @@ int do_adjtimex(struct timex *txc)
                 if (!(time_status & STA_NANO))
                         txc->offset /= NSEC_PER_USEC;
         }
-        txc->freq          = (time_freq / NSEC_PER_USEC) <<
-                                (SHIFT_USEC - SHIFT_NSEC);
+        txc->freq          = shift_right((s32)(time_freq >> PPM_SCALE_INV_SHIFT) *
+                                         (s64)PPM_SCALE_INV,
+                                         TICK_LENGTH_SHIFT);
         txc->maxerror      = time_maxerror;
         txc->esterror      = time_esterror;
         txc->status        = time_status;
         txc->constant      = time_constant;
         txc->precision     = 1;
-        txc->tolerance     = MAXFREQ;
+        txc->tolerance     = MAXFREQ_SCALED / PPM_SCALE;
         txc->tick          = tick_usec;
 
         /* PPS is not implemented, so these are zero */