blob: 6df8927c58a5bbedcab9efceac7c21985bec0bf0 [file] [log] [blame]
john stultz4c7ee8d2006-09-30 23:28:22 -07001/*
john stultz4c7ee8d2006-09-30 23:28:22 -07002 * NTP state machine interfaces and logic.
3 *
4 * This code was mainly moved from kernel/timer.c and kernel/time.c
5 * Please see those files for relevant copyright info and historical
6 * changelogs.
7 */
Alexey Dobriyanaa0ac362007-07-15 23:40:39 -07008#include <linux/capability.h>
Roman Zippel7dffa3c2008-05-01 04:34:41 -07009#include <linux/clocksource.h>
Maciej W. Rozyckieb3f9382008-09-22 14:42:40 -070010#include <linux/workqueue.h>
Ingo Molnar53bbfa92008-02-20 07:58:42 +010011#include <linux/hrtimer.h>
12#include <linux/jiffies.h>
13#include <linux/math64.h>
14#include <linux/timex.h>
15#include <linux/time.h>
16#include <linux/mm.h>
Alexander Gordeev025b40a2011-01-12 17:00:56 -080017#include <linux/module.h>
Jason Gunthorpe023f3332012-12-17 14:30:53 -070018#include <linux/rtc.h>
DengChaoc7963482015-12-13 12:26:42 +080019#include <linux/math64.h>
john stultz4c7ee8d2006-09-30 23:28:22 -070020
John Stultzaa6f9c592013-03-22 11:31:29 -070021#include "ntp_internal.h"
DengChao0af86462015-12-13 12:24:19 +080022#include "timekeeping_internal.h"
23
Torben Hohne2830b52011-01-27 16:00:32 +010024
Roman Zippelb0ee7552006-09-30 23:28:22 -070025/*
Ingo Molnar53bbfa92008-02-20 07:58:42 +010026 * NTP timekeeping variables:
John Stultza076b212013-03-22 11:52:03 -070027 *
28 * Note: All of the NTP state is protected by the timekeeping locks.
Roman Zippelb0ee7552006-09-30 23:28:22 -070029 */
Roman Zippelb0ee7552006-09-30 23:28:22 -070030
John Stultzbd331262011-11-14 13:48:36 -080031
Ingo Molnar53bbfa92008-02-20 07:58:42 +010032/* USER_HZ period (usecs): */
33unsigned long tick_usec = TICK_USEC;
Roman Zippel7dffa3c2008-05-01 04:34:41 -070034
John Stultz02ab20a2012-07-27 14:48:10 -040035/* SHIFTED_HZ period (nsecs): */
Ingo Molnar53bbfa92008-02-20 07:58:42 +010036unsigned long tick_nsec;
37
John Stultzea7cf492011-11-14 13:18:07 -080038static u64 tick_length;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010039static u64 tick_length_base;
40
John Stultz90bf3612015-06-11 15:54:54 -070041#define SECS_PER_DAY 86400
Ingo Molnarbbd12672009-02-22 12:11:11 +010042#define MAX_TICKADJ 500LL /* usecs */
Ingo Molnar53bbfa92008-02-20 07:58:42 +010043#define MAX_TICKADJ_SCALED \
Ingo Molnarbbd12672009-02-22 12:11:11 +010044 (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
john stultz4c7ee8d2006-09-30 23:28:22 -070045
46/*
47 * phase-lock loop variables
48 */
Ingo Molnar53bbfa92008-02-20 07:58:42 +010049
50/*
51 * clock synchronization status
52 *
53 * (TIME_ERROR prevents overwriting the CMOS clock)
54 */
55static int time_state = TIME_OK;
56
57/* clock status bits: */
John Stultz83579292011-11-14 13:06:21 -080058static int time_status = STA_UNSYNC;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010059
Ingo Molnar53bbfa92008-02-20 07:58:42 +010060/* time adjustment (nsecs): */
61static s64 time_offset;
62
63/* pll time constant: */
64static long time_constant = 2;
65
66/* maximum error (usecs): */
john stultz1f5b8f82010-01-28 15:02:41 -080067static long time_maxerror = NTP_PHASE_LIMIT;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010068
69/* estimated error (usecs): */
john stultz1f5b8f82010-01-28 15:02:41 -080070static long time_esterror = NTP_PHASE_LIMIT;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010071
72/* frequency offset (scaled nsecs/secs): */
73static s64 time_freq;
74
75/* time at last adjustment (secs): */
DengChao0af86462015-12-13 12:24:19 +080076static time64_t time_reftime;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010077
John Stultze1292ba2010-03-18 20:19:27 -070078static long time_adjust;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010079
Ingo Molnar069569e2009-02-22 16:03:37 +010080/* constant (boot-param configurable) NTP tick adjustment (upscaled) */
81static s64 ntp_tick_adj;
Ingo Molnar53bbfa92008-02-20 07:58:42 +010082
John Stultz833f32d2015-06-11 15:54:55 -070083/* second value of the next pending leapsecond, or TIME64_MAX if no leap */
84static time64_t ntp_next_leap_sec = TIME64_MAX;
85
Alexander Gordeev025b40a2011-01-12 17:00:56 -080086#ifdef CONFIG_NTP_PPS
87
88/*
89 * The following variables are used when a pulse-per-second (PPS) signal
90 * is available. They establish the engineering parameters of the clock
91 * discipline loop when controlled by the PPS signal.
92 */
93#define PPS_VALID 10 /* PPS signal watchdog max (s) */
94#define PPS_POPCORN 4 /* popcorn spike threshold (shift) */
95#define PPS_INTMIN 2 /* min freq interval (s) (shift) */
96#define PPS_INTMAX 8 /* max freq interval (s) (shift) */
97#define PPS_INTCOUNT 4 /* number of consecutive good intervals to
98 increase pps_shift or consecutive bad
99 intervals to decrease it */
100#define PPS_MAXWANDER 100000 /* max PPS freq wander (ns/s) */
101
102static int pps_valid; /* signal watchdog counter */
103static long pps_tf[3]; /* phase median filter */
104static long pps_jitter; /* current jitter (ns) */
Arnd Bergmann7ec88e42015-09-28 22:21:28 +0200105static struct timespec64 pps_fbase; /* beginning of the last freq interval */
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800106static int pps_shift; /* current interval duration (s) (shift) */
107static int pps_intcnt; /* interval counter */
108static s64 pps_freq; /* frequency offset (scaled ns/s) */
109static long pps_stabil; /* current stability (scaled ns/s) */
110
111/*
112 * PPS signal quality monitors
113 */
114static long pps_calcnt; /* calibration intervals */
115static long pps_jitcnt; /* jitter limit exceeded */
116static long pps_stbcnt; /* stability limit exceeded */
117static long pps_errcnt; /* calibration errors */
118
119
120/* PPS kernel consumer compensates the whole phase error immediately.
121 * Otherwise, reduce the offset by a fixed factor times the time constant.
122 */
123static inline s64 ntp_offset_chunk(s64 offset)
124{
125 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
126 return offset;
127 else
128 return shift_right(offset, SHIFT_PLL + time_constant);
129}
130
131static inline void pps_reset_freq_interval(void)
132{
133 /* the PPS calibration interval may end
134 surprisingly early */
135 pps_shift = PPS_INTMIN;
136 pps_intcnt = 0;
137}
138
139/**
140 * pps_clear - Clears the PPS state variables
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800141 */
142static inline void pps_clear(void)
143{
144 pps_reset_freq_interval();
145 pps_tf[0] = 0;
146 pps_tf[1] = 0;
147 pps_tf[2] = 0;
148 pps_fbase.tv_sec = pps_fbase.tv_nsec = 0;
149 pps_freq = 0;
150}
151
152/* Decrease pps_valid to indicate that another second has passed since
153 * the last PPS signal. When it reaches 0, indicate that PPS signal is
154 * missing.
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800155 */
156static inline void pps_dec_valid(void)
157{
158 if (pps_valid > 0)
159 pps_valid--;
160 else {
161 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
162 STA_PPSWANDER | STA_PPSERROR);
163 pps_clear();
164 }
165}
166
167static inline void pps_set_freq(s64 freq)
168{
169 pps_freq = freq;
170}
171
172static inline int is_error_status(int status)
173{
George Spelvinea54bca32014-05-12 09:35:48 -0400174 return (status & (STA_UNSYNC|STA_CLOCKERR))
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800175 /* PPS signal lost when either PPS time or
176 * PPS frequency synchronization requested
177 */
George Spelvinea54bca32014-05-12 09:35:48 -0400178 || ((status & (STA_PPSFREQ|STA_PPSTIME))
179 && !(status & STA_PPSSIGNAL))
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800180 /* PPS jitter exceeded when
181 * PPS time synchronization requested */
George Spelvinea54bca32014-05-12 09:35:48 -0400182 || ((status & (STA_PPSTIME|STA_PPSJITTER))
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800183 == (STA_PPSTIME|STA_PPSJITTER))
184 /* PPS wander exceeded or calibration error when
185 * PPS frequency synchronization requested
186 */
George Spelvinea54bca32014-05-12 09:35:48 -0400187 || ((status & STA_PPSFREQ)
188 && (status & (STA_PPSWANDER|STA_PPSERROR)));
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800189}
190
191static inline void pps_fill_timex(struct timex *txc)
192{
193 txc->ppsfreq = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) *
194 PPM_SCALE_INV, NTP_SCALE_SHIFT);
195 txc->jitter = pps_jitter;
196 if (!(time_status & STA_NANO))
197 txc->jitter /= NSEC_PER_USEC;
198 txc->shift = pps_shift;
199 txc->stabil = pps_stabil;
200 txc->jitcnt = pps_jitcnt;
201 txc->calcnt = pps_calcnt;
202 txc->errcnt = pps_errcnt;
203 txc->stbcnt = pps_stbcnt;
204}
205
206#else /* !CONFIG_NTP_PPS */
207
208static inline s64 ntp_offset_chunk(s64 offset)
209{
210 return shift_right(offset, SHIFT_PLL + time_constant);
211}
212
213static inline void pps_reset_freq_interval(void) {}
214static inline void pps_clear(void) {}
215static inline void pps_dec_valid(void) {}
216static inline void pps_set_freq(s64 freq) {}
217
218static inline int is_error_status(int status)
219{
220 return status & (STA_UNSYNC|STA_CLOCKERR);
221}
222
223static inline void pps_fill_timex(struct timex *txc)
224{
225 /* PPS is not implemented, so these are zero */
226 txc->ppsfreq = 0;
227 txc->jitter = 0;
228 txc->shift = 0;
229 txc->stabil = 0;
230 txc->jitcnt = 0;
231 txc->calcnt = 0;
232 txc->errcnt = 0;
233 txc->stbcnt = 0;
234}
235
236#endif /* CONFIG_NTP_PPS */
237
John Stultz83579292011-11-14 13:06:21 -0800238
239/**
240 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
241 *
242 */
243static inline int ntp_synced(void)
244{
245 return !(time_status & STA_UNSYNC);
246}
247
248
Ingo Molnar53bbfa92008-02-20 07:58:42 +0100249/*
250 * NTP methods:
251 */
john stultz4c7ee8d2006-09-30 23:28:22 -0700252
Ingo Molnar9ce616a2009-02-22 12:42:59 +0100253/*
254 * Update (tick_length, tick_length_base, tick_nsec), based
255 * on (tick_usec, ntp_tick_adj, time_freq):
256 */
Adrian Bunk70bc42f2006-09-30 23:28:29 -0700257static void ntp_update_frequency(void)
258{
Ingo Molnar9ce616a2009-02-22 12:42:59 +0100259 u64 second_length;
Ingo Molnarbc26c312009-02-22 12:17:36 +0100260 u64 new_base;
Adrian Bunk70bc42f2006-09-30 23:28:29 -0700261
Ingo Molnar9ce616a2009-02-22 12:42:59 +0100262 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
263 << NTP_SCALE_SHIFT;
264
Ingo Molnar069569e2009-02-22 16:03:37 +0100265 second_length += ntp_tick_adj;
Ingo Molnar9ce616a2009-02-22 12:42:59 +0100266 second_length += time_freq;
267
Ingo Molnar9ce616a2009-02-22 12:42:59 +0100268 tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
Ingo Molnarbc26c312009-02-22 12:17:36 +0100269 new_base = div_u64(second_length, NTP_INTERVAL_FREQ);
john stultzfdcedf72009-02-18 16:02:22 -0800270
271 /*
272 * Don't wait for the next second_overflow, apply
Ingo Molnarbc26c312009-02-22 12:17:36 +0100273 * the change to the tick length immediately:
john stultzfdcedf72009-02-18 16:02:22 -0800274 */
Ingo Molnarbc26c312009-02-22 12:17:36 +0100275 tick_length += new_base - tick_length_base;
276 tick_length_base = new_base;
Adrian Bunk70bc42f2006-09-30 23:28:29 -0700277}
278
Ingo Molnar478b7aa2009-02-22 13:22:23 +0100279static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
Ingo Molnarf9398902009-02-22 12:57:49 +0100280{
281 time_status &= ~STA_MODE;
282
283 if (secs < MINSEC)
Ingo Molnar478b7aa2009-02-22 13:22:23 +0100284 return 0;
Ingo Molnarf9398902009-02-22 12:57:49 +0100285
286 if (!(time_status & STA_FLL) && (secs <= MAXSEC))
Ingo Molnar478b7aa2009-02-22 13:22:23 +0100287 return 0;
Ingo Molnarf9398902009-02-22 12:57:49 +0100288
Ingo Molnarf9398902009-02-22 12:57:49 +0100289 time_status |= STA_MODE;
290
Sasha Levina078c6d2012-03-15 12:36:14 -0400291 return div64_long(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
Ingo Molnarf9398902009-02-22 12:57:49 +0100292}
293
Roman Zippelee9851b2008-05-01 04:34:32 -0700294static void ntp_update_offset(long offset)
295{
Roman Zippelee9851b2008-05-01 04:34:32 -0700296 s64 freq_adj;
Ingo Molnarf9398902009-02-22 12:57:49 +0100297 s64 offset64;
298 long secs;
Roman Zippelee9851b2008-05-01 04:34:32 -0700299
300 if (!(time_status & STA_PLL))
301 return;
302
Sasha Levin52d189f2015-12-03 15:46:48 -0500303 if (!(time_status & STA_NANO)) {
304 /* Make sure the multiplication below won't overflow */
305 offset = clamp(offset, -USEC_PER_SEC, USEC_PER_SEC);
Roman Zippel9f14f662008-05-01 04:34:36 -0700306 offset *= NSEC_PER_USEC;
Sasha Levin52d189f2015-12-03 15:46:48 -0500307 }
Roman Zippelee9851b2008-05-01 04:34:32 -0700308
309 /*
310 * Scale the phase adjustment and
311 * clamp to the operating range.
312 */
Sasha Levin52d189f2015-12-03 15:46:48 -0500313 offset = clamp(offset, -MAXPHASE, MAXPHASE);
Roman Zippelee9851b2008-05-01 04:34:32 -0700314
315 /*
316 * Select how the frequency is to be controlled
317 * and in which mode (PLL or FLL).
318 */
DengChao0af86462015-12-13 12:24:19 +0800319 secs = (long)(__ktime_get_real_seconds() - time_reftime);
Ingo Molnar10dd31a2009-02-22 13:38:40 +0100320 if (unlikely(time_status & STA_FREQHOLD))
Ingo Molnarc7986ac2009-02-22 13:29:09 +0100321 secs = 0;
322
DengChao0af86462015-12-13 12:24:19 +0800323 time_reftime = __ktime_get_real_seconds();
Roman Zippelee9851b2008-05-01 04:34:32 -0700324
Ingo Molnarf9398902009-02-22 12:57:49 +0100325 offset64 = offset;
Miroslav Lichvar8af3c152010-09-07 16:43:46 +0200326 freq_adj = ntp_update_offset_fll(offset64, secs);
Roman Zippel9f14f662008-05-01 04:34:36 -0700327
Miroslav Lichvar8af3c152010-09-07 16:43:46 +0200328 /*
329 * Clamp update interval to reduce PLL gain with low
330 * sampling rate (e.g. intermittent network connection)
331 * to avoid instability.
332 */
333 if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
334 secs = 1 << (SHIFT_PLL + 1 + time_constant);
335
336 freq_adj += (offset64 * secs) <<
337 (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
Ingo Molnarf9398902009-02-22 12:57:49 +0100338
339 freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED);
340
341 time_freq = max(freq_adj, -MAXFREQ_SCALED);
342
343 time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
Roman Zippelee9851b2008-05-01 04:34:32 -0700344}
345
Roman Zippelb0ee7552006-09-30 23:28:22 -0700346/**
347 * ntp_clear - Clears the NTP state variables
Roman Zippelb0ee7552006-09-30 23:28:22 -0700348 */
349void ntp_clear(void)
350{
Ingo Molnar53bbfa92008-02-20 07:58:42 +0100351 time_adjust = 0; /* stop active adjtime() */
352 time_status |= STA_UNSYNC;
353 time_maxerror = NTP_PHASE_LIMIT;
354 time_esterror = NTP_PHASE_LIMIT;
Roman Zippelb0ee7552006-09-30 23:28:22 -0700355
356 ntp_update_frequency();
357
Ingo Molnar53bbfa92008-02-20 07:58:42 +0100358 tick_length = tick_length_base;
359 time_offset = 0;
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800360
John Stultz833f32d2015-06-11 15:54:55 -0700361 ntp_next_leap_sec = TIME64_MAX;
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800362 /* Clear PPS state variables */
363 pps_clear();
Roman Zippelb0ee7552006-09-30 23:28:22 -0700364}
365
John Stultzea7cf492011-11-14 13:18:07 -0800366
367u64 ntp_tick_length(void)
368{
John Stultza076b212013-03-22 11:52:03 -0700369 return tick_length;
John Stultzea7cf492011-11-14 13:18:07 -0800370}
371
John Stultz833f32d2015-06-11 15:54:55 -0700372/**
373 * ntp_get_next_leap - Returns the next leapsecond in CLOCK_REALTIME ktime_t
374 *
375 * Provides the time of the next leapsecond against CLOCK_REALTIME in
376 * a ktime_t format. Returns KTIME_MAX if no leapsecond is pending.
377 */
378ktime_t ntp_get_next_leap(void)
379{
380 ktime_t ret;
381
382 if ((time_state == TIME_INS) && (time_status & STA_INS))
383 return ktime_set(ntp_next_leap_sec, 0);
384 ret.tv64 = KTIME_MAX;
385 return ret;
386}
John Stultzea7cf492011-11-14 13:18:07 -0800387
john stultz4c7ee8d2006-09-30 23:28:22 -0700388/*
389 * this routine handles the overflow of the microsecond field
390 *
391 * The tricky bits of code to handle the accurate clock support
392 * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
393 * They were originally developed for SUN and DEC kernels.
394 * All the kudos should go to Dave for this stuff.
John Stultz6b43ae82012-03-15 13:04:03 -0700395 *
396 * Also handles leap second processing, and returns leap offset
john stultz4c7ee8d2006-09-30 23:28:22 -0700397 */
DengChaoc7963482015-12-13 12:26:42 +0800398int second_overflow(time64_t secs)
john stultz4c7ee8d2006-09-30 23:28:22 -0700399{
Ingo Molnar39854fe2009-02-22 16:06:58 +0100400 s64 delta;
John Stultz6b43ae82012-03-15 13:04:03 -0700401 int leap = 0;
DengChaoc7963482015-12-13 12:26:42 +0800402 s32 rem;
john stultz4c7ee8d2006-09-30 23:28:22 -0700403
John Stultz6b43ae82012-03-15 13:04:03 -0700404 /*
405 * Leap second processing. If in leap-insert state at the end of the
406 * day, the system clock is set back one second; if in leap-delete
407 * state, the system clock is set ahead one second.
408 */
409 switch (time_state) {
410 case TIME_OK:
John Stultz833f32d2015-06-11 15:54:55 -0700411 if (time_status & STA_INS) {
John Stultz6b43ae82012-03-15 13:04:03 -0700412 time_state = TIME_INS;
DengChaoc7963482015-12-13 12:26:42 +0800413 div_s64_rem(secs, SECS_PER_DAY, &rem);
414 ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
John Stultz833f32d2015-06-11 15:54:55 -0700415 } else if (time_status & STA_DEL) {
John Stultz6b43ae82012-03-15 13:04:03 -0700416 time_state = TIME_DEL;
DengChaoc7963482015-12-13 12:26:42 +0800417 div_s64_rem(secs + 1, SECS_PER_DAY, &rem);
418 ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
John Stultz833f32d2015-06-11 15:54:55 -0700419 }
John Stultz6b43ae82012-03-15 13:04:03 -0700420 break;
421 case TIME_INS:
John Stultz833f32d2015-06-11 15:54:55 -0700422 if (!(time_status & STA_INS)) {
423 ntp_next_leap_sec = TIME64_MAX;
John Stultz6b1859d2012-07-13 01:21:50 -0400424 time_state = TIME_OK;
DengChaoc7963482015-12-13 12:26:42 +0800425 } else if (secs == ntp_next_leap_sec) {
John Stultz6b43ae82012-03-15 13:04:03 -0700426 leap = -1;
427 time_state = TIME_OOP;
428 printk(KERN_NOTICE
429 "Clock: inserting leap second 23:59:60 UTC\n");
430 }
431 break;
432 case TIME_DEL:
John Stultz833f32d2015-06-11 15:54:55 -0700433 if (!(time_status & STA_DEL)) {
434 ntp_next_leap_sec = TIME64_MAX;
John Stultz6b1859d2012-07-13 01:21:50 -0400435 time_state = TIME_OK;
DengChaoc7963482015-12-13 12:26:42 +0800436 } else if (secs == ntp_next_leap_sec) {
John Stultz6b43ae82012-03-15 13:04:03 -0700437 leap = 1;
John Stultz833f32d2015-06-11 15:54:55 -0700438 ntp_next_leap_sec = TIME64_MAX;
John Stultz6b43ae82012-03-15 13:04:03 -0700439 time_state = TIME_WAIT;
440 printk(KERN_NOTICE
441 "Clock: deleting leap second 23:59:59 UTC\n");
442 }
443 break;
444 case TIME_OOP:
John Stultz833f32d2015-06-11 15:54:55 -0700445 ntp_next_leap_sec = TIME64_MAX;
John Stultz6b43ae82012-03-15 13:04:03 -0700446 time_state = TIME_WAIT;
447 break;
John Stultz6b43ae82012-03-15 13:04:03 -0700448 case TIME_WAIT:
449 if (!(time_status & (STA_INS | STA_DEL)))
450 time_state = TIME_OK;
451 break;
452 }
453
454
john stultz4c7ee8d2006-09-30 23:28:22 -0700455 /* Bump the maxerror field */
Roman Zippel074b3b82008-05-01 04:34:34 -0700456 time_maxerror += MAXFREQ / NSEC_PER_USEC;
john stultz4c7ee8d2006-09-30 23:28:22 -0700457 if (time_maxerror > NTP_PHASE_LIMIT) {
458 time_maxerror = NTP_PHASE_LIMIT;
459 time_status |= STA_UNSYNC;
460 }
461
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800462 /* Compute the phase adjustment for the next second */
Ingo Molnar39854fe2009-02-22 16:06:58 +0100463 tick_length = tick_length_base;
464
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800465 delta = ntp_offset_chunk(time_offset);
Ingo Molnar39854fe2009-02-22 16:06:58 +0100466 time_offset -= delta;
467 tick_length += delta;
john stultz4c7ee8d2006-09-30 23:28:22 -0700468
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800469 /* Check PPS signal */
470 pps_dec_valid();
471
Ingo Molnar3c972c22009-02-22 12:06:57 +0100472 if (!time_adjust)
John Stultzbd331262011-11-14 13:48:36 -0800473 goto out;
Ingo Molnar3c972c22009-02-22 12:06:57 +0100474
475 if (time_adjust > MAX_TICKADJ) {
476 time_adjust -= MAX_TICKADJ;
477 tick_length += MAX_TICKADJ_SCALED;
John Stultzbd331262011-11-14 13:48:36 -0800478 goto out;
john stultz4c7ee8d2006-09-30 23:28:22 -0700479 }
Ingo Molnar3c972c22009-02-22 12:06:57 +0100480
481 if (time_adjust < -MAX_TICKADJ) {
482 time_adjust += MAX_TICKADJ;
483 tick_length -= MAX_TICKADJ_SCALED;
John Stultzbd331262011-11-14 13:48:36 -0800484 goto out;
Ingo Molnar3c972c22009-02-22 12:06:57 +0100485 }
486
487 tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
488 << NTP_SCALE_SHIFT;
489 time_adjust = 0;
John Stultz6b43ae82012-03-15 13:04:03 -0700490
John Stultzbd331262011-11-14 13:48:36 -0800491out:
John Stultz6b43ae82012-03-15 13:04:03 -0700492 return leap;
john stultz4c7ee8d2006-09-30 23:28:22 -0700493}
494
Xunlei Pang3c00a1f2015-04-01 20:34:23 -0700495#ifdef CONFIG_GENERIC_CMOS_UPDATE
Xunlei Pang7494e9e2015-07-26 18:45:39 +0800496int __weak update_persistent_clock(struct timespec now)
497{
498 return -ENODEV;
499}
500
Xunlei Pang3c00a1f2015-04-01 20:34:23 -0700501int __weak update_persistent_clock64(struct timespec64 now64)
502{
503 struct timespec now;
504
505 now = timespec64_to_timespec(now64);
506 return update_persistent_clock(now);
507}
508#endif
509
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700510#if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC)
Maciej W. Rozyckieb3f9382008-09-22 14:42:40 -0700511static void sync_cmos_clock(struct work_struct *work);
Thomas Gleixner82644452007-07-21 04:37:37 -0700512
Maciej W. Rozyckieb3f9382008-09-22 14:42:40 -0700513static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
Thomas Gleixner82644452007-07-21 04:37:37 -0700514
Maciej W. Rozyckieb3f9382008-09-22 14:42:40 -0700515static void sync_cmos_clock(struct work_struct *work)
john stultz4c7ee8d2006-09-30 23:28:22 -0700516{
Thomas Gleixnerd6d29892014-07-16 21:04:04 +0000517 struct timespec64 now;
Arnd Bergmann5fd96c42015-09-28 22:21:30 +0200518 struct timespec64 next;
Thomas Gleixner82644452007-07-21 04:37:37 -0700519 int fail = 1;
520
521 /*
522 * If we have an externally synchronized Linux clock, then update
523 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
524 * called as close as possible to 500 ms before the new second starts.
525 * This code is run on a timer. If the clock is set, that timer
526 * may not expire at the correct time. Thus, we adjust...
Miroslav Lichvara97ad0c2013-08-01 19:31:35 +0200527 * We want the clock to be within a couple of ticks from the target.
Thomas Gleixner82644452007-07-21 04:37:37 -0700528 */
Ingo Molnar53bbfa92008-02-20 07:58:42 +0100529 if (!ntp_synced()) {
Thomas Gleixner82644452007-07-21 04:37:37 -0700530 /*
531 * Not synced, exit, do not restart a timer (if one is
532 * running, let it run out).
533 */
534 return;
Ingo Molnar53bbfa92008-02-20 07:58:42 +0100535 }
Thomas Gleixner82644452007-07-21 04:37:37 -0700536
Thomas Gleixnerd6d29892014-07-16 21:04:04 +0000537 getnstimeofday64(&now);
Miroslav Lichvara97ad0c2013-08-01 19:31:35 +0200538 if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec * 5) {
Xunlei Pang9a4a4452015-01-22 02:31:55 +0000539 struct timespec64 adjust = now;
Prarit Bhargava84e345e2013-02-08 17:59:53 -0500540
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700541 fail = -ENODEV;
Prarit Bhargava84e345e2013-02-08 17:59:53 -0500542 if (persistent_clock_is_local)
543 adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700544#ifdef CONFIG_GENERIC_CMOS_UPDATE
Xunlei Pang3c00a1f2015-04-01 20:34:23 -0700545 fail = update_persistent_clock64(adjust);
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700546#endif
Xunlei Pang3c00a1f2015-04-01 20:34:23 -0700547
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700548#ifdef CONFIG_RTC_SYSTOHC
549 if (fail == -ENODEV)
Prarit Bhargava84e345e2013-02-08 17:59:53 -0500550 fail = rtc_set_ntp_time(adjust);
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700551#endif
552 }
Thomas Gleixner82644452007-07-21 04:37:37 -0700553
Maciej W. Rozycki4ff4b9e2008-09-05 14:05:31 -0700554 next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
Thomas Gleixner82644452007-07-21 04:37:37 -0700555 if (next.tv_nsec <= 0)
556 next.tv_nsec += NSEC_PER_SEC;
557
Jason Gunthorpe023f3332012-12-17 14:30:53 -0700558 if (!fail || fail == -ENODEV)
Thomas Gleixner82644452007-07-21 04:37:37 -0700559 next.tv_sec = 659;
560 else
561 next.tv_sec = 0;
562
563 if (next.tv_nsec >= NSEC_PER_SEC) {
564 next.tv_sec++;
565 next.tv_nsec -= NSEC_PER_SEC;
566 }
Shaibal Duttae8b17592014-01-31 11:18:24 -0800567 queue_delayed_work(system_power_efficient_wq,
Arnd Bergmann5fd96c42015-09-28 22:21:30 +0200568 &sync_cmos_work, timespec64_to_jiffies(&next));
john stultz4c7ee8d2006-09-30 23:28:22 -0700569}
570
John Stultz7bd36012013-09-11 16:50:56 -0700571void ntp_notify_cmos_timer(void)
Thomas Gleixner82644452007-07-21 04:37:37 -0700572{
Shaibal Duttae8b17592014-01-31 11:18:24 -0800573 queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
Thomas Gleixner82644452007-07-21 04:37:37 -0700574}
575
576#else
John Stultz7bd36012013-09-11 16:50:56 -0700577void ntp_notify_cmos_timer(void) { }
Thomas Gleixner82644452007-07-21 04:37:37 -0700578#endif
579
Ingo Molnar80f22572009-02-22 15:15:32 +0100580
581/*
582 * Propagate a new txc->status value into the NTP state:
583 */
John Stultz7d489d12014-07-16 21:04:01 +0000584static inline void process_adj_status(struct timex *txc, struct timespec64 *ts)
Ingo Molnar80f22572009-02-22 15:15:32 +0100585{
Ingo Molnar80f22572009-02-22 15:15:32 +0100586 if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
587 time_state = TIME_OK;
588 time_status = STA_UNSYNC;
John Stultz833f32d2015-06-11 15:54:55 -0700589 ntp_next_leap_sec = TIME64_MAX;
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800590 /* restart PPS frequency calibration */
591 pps_reset_freq_interval();
Ingo Molnar80f22572009-02-22 15:15:32 +0100592 }
Ingo Molnar80f22572009-02-22 15:15:32 +0100593
594 /*
595 * If we turn on PLL adjustments then reset the
596 * reference time to current time.
597 */
598 if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
DengChao0af86462015-12-13 12:24:19 +0800599 time_reftime = __ktime_get_real_seconds();
Ingo Molnar80f22572009-02-22 15:15:32 +0100600
John Stultza2a5ac82009-02-26 09:46:14 -0800601 /* only set allowed bits */
602 time_status &= STA_RONLY;
Ingo Molnar80f22572009-02-22 15:15:32 +0100603 time_status |= txc->status & ~STA_RONLY;
Ingo Molnar80f22572009-02-22 15:15:32 +0100604}
Richard Cochrancd5398b2012-04-27 10:12:41 +0200605
John Stultza076b212013-03-22 11:52:03 -0700606
John Stultzcc244dd2012-05-03 12:30:07 -0700607static inline void process_adjtimex_modes(struct timex *txc,
John Stultz7d489d12014-07-16 21:04:01 +0000608 struct timespec64 *ts,
John Stultzcc244dd2012-05-03 12:30:07 -0700609 s32 *time_tai)
Ingo Molnar80f22572009-02-22 15:15:32 +0100610{
611 if (txc->modes & ADJ_STATUS)
612 process_adj_status(txc, ts);
613
614 if (txc->modes & ADJ_NANO)
615 time_status |= STA_NANO;
Ingo Molnare9629162009-02-22 15:35:18 +0100616
Ingo Molnar80f22572009-02-22 15:15:32 +0100617 if (txc->modes & ADJ_MICRO)
618 time_status &= ~STA_NANO;
619
620 if (txc->modes & ADJ_FREQUENCY) {
Ingo Molnar2b9d1492009-02-22 15:48:43 +0100621 time_freq = txc->freq * PPM_SCALE;
Ingo Molnar80f22572009-02-22 15:15:32 +0100622 time_freq = min(time_freq, MAXFREQ_SCALED);
623 time_freq = max(time_freq, -MAXFREQ_SCALED);
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800624 /* update pps_freq */
625 pps_set_freq(time_freq);
Ingo Molnar80f22572009-02-22 15:15:32 +0100626 }
627
628 if (txc->modes & ADJ_MAXERROR)
629 time_maxerror = txc->maxerror;
Ingo Molnare9629162009-02-22 15:35:18 +0100630
Ingo Molnar80f22572009-02-22 15:15:32 +0100631 if (txc->modes & ADJ_ESTERROR)
632 time_esterror = txc->esterror;
633
634 if (txc->modes & ADJ_TIMECONST) {
635 time_constant = txc->constant;
636 if (!(time_status & STA_NANO))
637 time_constant += 4;
638 time_constant = min(time_constant, (long)MAXTC);
639 time_constant = max(time_constant, 0l);
640 }
641
642 if (txc->modes & ADJ_TAI && txc->constant > 0)
John Stultzcc244dd2012-05-03 12:30:07 -0700643 *time_tai = txc->constant;
Ingo Molnar80f22572009-02-22 15:15:32 +0100644
645 if (txc->modes & ADJ_OFFSET)
646 ntp_update_offset(txc->offset);
Ingo Molnare9629162009-02-22 15:35:18 +0100647
Ingo Molnar80f22572009-02-22 15:15:32 +0100648 if (txc->modes & ADJ_TICK)
649 tick_usec = txc->tick;
650
651 if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
652 ntp_update_frequency();
653}
654
john stultz4c7ee8d2006-09-30 23:28:22 -0700655
John Stultzad460962013-03-22 11:59:04 -0700656
657/**
658 * ntp_validate_timex - Ensures the timex is ok for use in do_adjtimex
659 */
660int ntp_validate_timex(struct timex *txc)
661{
Roman Zippel916c7a82008-08-20 16:46:08 -0700662 if (txc->modes & ADJ_ADJTIME) {
Roman Zippeleea83d82008-05-01 04:34:33 -0700663 /* singleshot must not be used with any other mode bits */
Roman Zippel916c7a82008-08-20 16:46:08 -0700664 if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
john stultz4c7ee8d2006-09-30 23:28:22 -0700665 return -EINVAL;
Roman Zippel916c7a82008-08-20 16:46:08 -0700666 if (!(txc->modes & ADJ_OFFSET_READONLY) &&
667 !capable(CAP_SYS_TIME))
668 return -EPERM;
669 } else {
670 /* In order to modify anything, you gotta be super-user! */
671 if (txc->modes && !capable(CAP_SYS_TIME))
672 return -EPERM;
Ingo Molnar53bbfa92008-02-20 07:58:42 +0100673 /*
674 * if the quartz is off by more than 10% then
675 * something is VERY wrong!
676 */
Roman Zippel916c7a82008-08-20 16:46:08 -0700677 if (txc->modes & ADJ_TICK &&
678 (txc->tick < 900000/USER_HZ ||
679 txc->tick > 1100000/USER_HZ))
Ingo Molnare9629162009-02-22 15:35:18 +0100680 return -EINVAL;
John Stultz52bfb362007-11-26 20:42:19 +0100681 }
john stultz4c7ee8d2006-09-30 23:28:22 -0700682
John Stultz37cf4dc2015-12-03 22:09:31 -0500683 if (txc->modes & ADJ_SETOFFSET) {
684 /* In order to inject time, you gotta be super-user! */
685 if (!capable(CAP_SYS_TIME))
686 return -EPERM;
687
John Stultzdd4e17a2016-01-21 15:03:34 -0800688 if (txc->modes & ADJ_NANO) {
689 struct timespec ts;
690
691 ts.tv_sec = txc->time.tv_sec;
692 ts.tv_nsec = txc->time.tv_usec;
693 if (!timespec_inject_offset_valid(&ts))
694 return -EINVAL;
695
696 } else {
697 if (!timeval_inject_offset_valid(&txc->time))
698 return -EINVAL;
699 }
John Stultz37cf4dc2015-12-03 22:09:31 -0500700 }
John Stultzad460962013-03-22 11:59:04 -0700701
John Stultz29183a72015-02-09 23:30:36 -0800702 /*
703 * Check for potential multiplication overflows that can
704 * only happen on 64-bit systems:
705 */
706 if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
707 if (LLONG_MIN / PPM_SCALE > txc->freq)
Sasha Levin5e5aeb42014-12-03 19:25:05 -0500708 return -EINVAL;
John Stultz29183a72015-02-09 23:30:36 -0800709 if (LLONG_MAX / PPM_SCALE < txc->freq)
Sasha Levin5e5aeb42014-12-03 19:25:05 -0500710 return -EINVAL;
711 }
712
John Stultzad460962013-03-22 11:59:04 -0700713 return 0;
714}
715
716
717/*
718 * adjtimex mainly allows reading (and writing, if superuser) of
719 * kernel time-keeping variables. used by xntpd.
720 */
John Stultz7d489d12014-07-16 21:04:01 +0000721int __do_adjtimex(struct timex *txc, struct timespec64 *ts, s32 *time_tai)
John Stultzad460962013-03-22 11:59:04 -0700722{
John Stultzad460962013-03-22 11:59:04 -0700723 int result;
724
Roman Zippel916c7a82008-08-20 16:46:08 -0700725 if (txc->modes & ADJ_ADJTIME) {
726 long save_adjust = time_adjust;
727
728 if (!(txc->modes & ADJ_OFFSET_READONLY)) {
729 /* adjtime() is independent from ntp_adjtime() */
730 time_adjust = txc->offset;
731 ntp_update_frequency();
732 }
733 txc->offset = save_adjust;
Ingo Molnare9629162009-02-22 15:35:18 +0100734 } else {
735
736 /* If there are input parameters, then process them: */
737 if (txc->modes)
John Stultz87ace392013-03-22 12:28:15 -0700738 process_adjtimex_modes(txc, ts, time_tai);
Ingo Molnare9629162009-02-22 15:35:18 +0100739
740 txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
741 NTP_SCALE_SHIFT);
742 if (!(time_status & STA_NANO))
743 txc->offset /= NSEC_PER_USEC;
Roman Zippel916c7a82008-08-20 16:46:08 -0700744 }
Roman Zippel916c7a82008-08-20 16:46:08 -0700745
Roman Zippeleea83d82008-05-01 04:34:33 -0700746 result = time_state; /* mostly `TIME_OK' */
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800747 /* check for errors */
748 if (is_error_status(time_status))
john stultz4c7ee8d2006-09-30 23:28:22 -0700749 result = TIME_ERROR;
750
Roman Zippeld40e9442008-09-22 14:42:44 -0700751 txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
Ingo Molnar2b9d1492009-02-22 15:48:43 +0100752 PPM_SCALE_INV, NTP_SCALE_SHIFT);
john stultz4c7ee8d2006-09-30 23:28:22 -0700753 txc->maxerror = time_maxerror;
754 txc->esterror = time_esterror;
755 txc->status = time_status;
756 txc->constant = time_constant;
Adrian Bunk70bc42f2006-09-30 23:28:29 -0700757 txc->precision = 1;
Roman Zippel074b3b82008-05-01 04:34:34 -0700758 txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
john stultz4c7ee8d2006-09-30 23:28:22 -0700759 txc->tick = tick_usec;
John Stultz87ace392013-03-22 12:28:15 -0700760 txc->tai = *time_tai;
john stultz4c7ee8d2006-09-30 23:28:22 -0700761
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800762 /* fill PPS status fields */
763 pps_fill_timex(txc);
Ingo Molnare9629162009-02-22 15:35:18 +0100764
John Stultz7d489d12014-07-16 21:04:01 +0000765 txc->time.tv_sec = (time_t)ts->tv_sec;
John Stultz87ace392013-03-22 12:28:15 -0700766 txc->time.tv_usec = ts->tv_nsec;
Roman Zippeleea83d82008-05-01 04:34:33 -0700767 if (!(time_status & STA_NANO))
768 txc->time.tv_usec /= NSEC_PER_USEC;
Roman Zippelee9851b2008-05-01 04:34:32 -0700769
John Stultz96efdcf2015-06-11 15:54:56 -0700770 /* Handle leapsec adjustments */
771 if (unlikely(ts->tv_sec >= ntp_next_leap_sec)) {
772 if ((time_state == TIME_INS) && (time_status & STA_INS)) {
773 result = TIME_OOP;
774 txc->tai++;
775 txc->time.tv_sec--;
776 }
777 if ((time_state == TIME_DEL) && (time_status & STA_DEL)) {
778 result = TIME_WAIT;
779 txc->tai--;
780 txc->time.tv_sec++;
781 }
782 if ((time_state == TIME_OOP) &&
783 (ts->tv_sec == ntp_next_leap_sec)) {
784 result = TIME_WAIT;
785 }
786 }
787
Roman Zippelee9851b2008-05-01 04:34:32 -0700788 return result;
john stultz4c7ee8d2006-09-30 23:28:22 -0700789}
Roman Zippel10a398d2008-03-04 15:14:26 -0800790
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800791#ifdef CONFIG_NTP_PPS
792
793/* actually struct pps_normtime is good old struct timespec, but it is
794 * semantically different (and it is the reason why it was invented):
795 * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ]
796 * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */
797struct pps_normtime {
Arnd Bergmann7ec88e42015-09-28 22:21:28 +0200798 s64 sec; /* seconds */
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800799 long nsec; /* nanoseconds */
800};
801
802/* normalize the timestamp so that nsec is in the
803 ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */
Arnd Bergmann7ec88e42015-09-28 22:21:28 +0200804static inline struct pps_normtime pps_normalize_ts(struct timespec64 ts)
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800805{
806 struct pps_normtime norm = {
807 .sec = ts.tv_sec,
808 .nsec = ts.tv_nsec
809 };
810
811 if (norm.nsec > (NSEC_PER_SEC >> 1)) {
812 norm.nsec -= NSEC_PER_SEC;
813 norm.sec++;
814 }
815
816 return norm;
817}
818
819/* get current phase correction and jitter */
820static inline long pps_phase_filter_get(long *jitter)
821{
822 *jitter = pps_tf[0] - pps_tf[1];
823 if (*jitter < 0)
824 *jitter = -*jitter;
825
826 /* TODO: test various filters */
827 return pps_tf[0];
828}
829
830/* add the sample to the phase filter */
831static inline void pps_phase_filter_add(long err)
832{
833 pps_tf[2] = pps_tf[1];
834 pps_tf[1] = pps_tf[0];
835 pps_tf[0] = err;
836}
837
838/* decrease frequency calibration interval length.
839 * It is halved after four consecutive unstable intervals.
840 */
841static inline void pps_dec_freq_interval(void)
842{
843 if (--pps_intcnt <= -PPS_INTCOUNT) {
844 pps_intcnt = -PPS_INTCOUNT;
845 if (pps_shift > PPS_INTMIN) {
846 pps_shift--;
847 pps_intcnt = 0;
848 }
849 }
850}
851
852/* increase frequency calibration interval length.
853 * It is doubled after four consecutive stable intervals.
854 */
855static inline void pps_inc_freq_interval(void)
856{
857 if (++pps_intcnt >= PPS_INTCOUNT) {
858 pps_intcnt = PPS_INTCOUNT;
859 if (pps_shift < PPS_INTMAX) {
860 pps_shift++;
861 pps_intcnt = 0;
862 }
863 }
864}
865
866/* update clock frequency based on MONOTONIC_RAW clock PPS signal
867 * timestamps
868 *
869 * At the end of the calibration interval the difference between the
870 * first and last MONOTONIC_RAW clock timestamps divided by the length
871 * of the interval becomes the frequency update. If the interval was
872 * too long, the data are discarded.
873 * Returns the difference between old and new frequency values.
874 */
875static long hardpps_update_freq(struct pps_normtime freq_norm)
876{
877 long delta, delta_mod;
878 s64 ftemp;
879
880 /* check if the frequency interval was too long */
881 if (freq_norm.sec > (2 << pps_shift)) {
882 time_status |= STA_PPSERROR;
883 pps_errcnt++;
884 pps_dec_freq_interval();
John Stultz6d9bcb62014-06-04 16:11:43 -0700885 printk_deferred(KERN_ERR
Arnd Bergmann7ec88e42015-09-28 22:21:28 +0200886 "hardpps: PPSERROR: interval too long - %lld s\n",
John Stultz6d9bcb62014-06-04 16:11:43 -0700887 freq_norm.sec);
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800888 return 0;
889 }
890
891 /* here the raw frequency offset and wander (stability) is
892 * calculated. If the wander is less than the wander threshold
893 * the interval is increased; otherwise it is decreased.
894 */
895 ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT,
896 freq_norm.sec);
897 delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT);
898 pps_freq = ftemp;
899 if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) {
John Stultz6d9bcb62014-06-04 16:11:43 -0700900 printk_deferred(KERN_WARNING
901 "hardpps: PPSWANDER: change=%ld\n", delta);
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800902 time_status |= STA_PPSWANDER;
903 pps_stbcnt++;
904 pps_dec_freq_interval();
905 } else { /* good sample */
906 pps_inc_freq_interval();
907 }
908
909 /* the stability metric is calculated as the average of recent
910 * frequency changes, but is used only for performance
911 * monitoring
912 */
913 delta_mod = delta;
914 if (delta_mod < 0)
915 delta_mod = -delta_mod;
916 pps_stabil += (div_s64(((s64)delta_mod) <<
917 (NTP_SCALE_SHIFT - SHIFT_USEC),
918 NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN;
919
920 /* if enabled, the system clock frequency is updated */
921 if ((time_status & STA_PPSFREQ) != 0 &&
922 (time_status & STA_FREQHOLD) == 0) {
923 time_freq = pps_freq;
924 ntp_update_frequency();
925 }
926
927 return delta;
928}
929
930/* correct REALTIME clock phase error against PPS signal */
931static void hardpps_update_phase(long error)
932{
933 long correction = -error;
934 long jitter;
935
936 /* add the sample to the median filter */
937 pps_phase_filter_add(correction);
938 correction = pps_phase_filter_get(&jitter);
939
940 /* Nominal jitter is due to PPS signal noise. If it exceeds the
941 * threshold, the sample is discarded; otherwise, if so enabled,
942 * the time offset is updated.
943 */
944 if (jitter > (pps_jitter << PPS_POPCORN)) {
John Stultz6d9bcb62014-06-04 16:11:43 -0700945 printk_deferred(KERN_WARNING
946 "hardpps: PPSJITTER: jitter=%ld, limit=%ld\n",
947 jitter, (pps_jitter << PPS_POPCORN));
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800948 time_status |= STA_PPSJITTER;
949 pps_jitcnt++;
950 } else if (time_status & STA_PPSTIME) {
951 /* correct the time using the phase offset */
952 time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT,
953 NTP_INTERVAL_FREQ);
954 /* cancel running adjtime() */
955 time_adjust = 0;
956 }
957 /* update jitter */
958 pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN;
959}
960
961/*
John Stultzaa6f9c592013-03-22 11:31:29 -0700962 * __hardpps() - discipline CPU clock oscillator to external PPS signal
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800963 *
964 * This routine is called at each PPS signal arrival in order to
965 * discipline the CPU clock oscillator to the PPS signal. It takes two
966 * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former
967 * is used to correct clock phase error and the latter is used to
968 * correct the frequency.
969 *
970 * This code is based on David Mills's reference nanokernel
971 * implementation. It was mostly rewritten but keeps the same idea.
972 */
Arnd Bergmann7ec88e42015-09-28 22:21:28 +0200973void __hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800974{
975 struct pps_normtime pts_norm, freq_norm;
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800976
977 pts_norm = pps_normalize_ts(*phase_ts);
978
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800979 /* clear the error bits, they will be set again if needed */
980 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
981
982 /* indicate signal presence */
983 time_status |= STA_PPSSIGNAL;
984 pps_valid = PPS_VALID;
985
986 /* when called for the first time,
987 * just start the frequency interval */
988 if (unlikely(pps_fbase.tv_sec == 0)) {
989 pps_fbase = *raw_ts;
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800990 return;
991 }
992
993 /* ok, now we have a base for frequency calculation */
Arnd Bergmann7ec88e42015-09-28 22:21:28 +0200994 freq_norm = pps_normalize_ts(timespec64_sub(*raw_ts, pps_fbase));
Alexander Gordeev025b40a2011-01-12 17:00:56 -0800995
996 /* check that the signal is in the range
997 * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */
998 if ((freq_norm.sec == 0) ||
999 (freq_norm.nsec > MAXFREQ * freq_norm.sec) ||
1000 (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) {
1001 time_status |= STA_PPSJITTER;
1002 /* restart the frequency calibration interval */
1003 pps_fbase = *raw_ts;
John Stultz6d9bcb62014-06-04 16:11:43 -07001004 printk_deferred(KERN_ERR "hardpps: PPSJITTER: bad pulse\n");
Alexander Gordeev025b40a2011-01-12 17:00:56 -08001005 return;
1006 }
1007
1008 /* signal is ok */
1009
1010 /* check if the current frequency interval is finished */
1011 if (freq_norm.sec >= (1 << pps_shift)) {
1012 pps_calcnt++;
1013 /* restart the frequency calibration interval */
1014 pps_fbase = *raw_ts;
1015 hardpps_update_freq(freq_norm);
1016 }
1017
1018 hardpps_update_phase(pts_norm.nsec);
1019
Alexander Gordeev025b40a2011-01-12 17:00:56 -08001020}
Alexander Gordeev025b40a2011-01-12 17:00:56 -08001021#endif /* CONFIG_NTP_PPS */
1022
Roman Zippel10a398d2008-03-04 15:14:26 -08001023static int __init ntp_tick_adj_setup(char *str)
1024{
Fabian Frederickcdafb932014-05-09 20:32:25 +02001025 int rc = kstrtol(str, 0, (long *)&ntp_tick_adj);
1026
1027 if (rc)
1028 return rc;
Ingo Molnar069569e2009-02-22 16:03:37 +01001029 ntp_tick_adj <<= NTP_SCALE_SHIFT;
1030
Roman Zippel10a398d2008-03-04 15:14:26 -08001031 return 1;
1032}
1033
1034__setup("ntp_tick_adj=", ntp_tick_adj_setup);
Roman Zippel7dffa3c2008-05-01 04:34:41 -07001035
1036void __init ntp_init(void)
1037{
1038 ntp_clear();
Roman Zippel7dffa3c2008-05-01 04:34:41 -07001039}