Commit | Line | Data |
---|---|---|
4c7ee8de | 1 | /* |
4c7ee8de | 2 | * 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 | */ | |
aa0ac365 | 8 | #include <linux/capability.h> |
7dffa3c6 | 9 | #include <linux/clocksource.h> |
eb3f938f | 10 | #include <linux/workqueue.h> |
53bbfa9e IM |
11 | #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> | |
025b40ab | 17 | #include <linux/module.h> |
4c7ee8de | 18 | |
e2830b5c TH |
19 | #include "tick-internal.h" |
20 | ||
b0ee7556 | 21 | /* |
53bbfa9e | 22 | * NTP timekeeping variables: |
b0ee7556 | 23 | */ |
b0ee7556 | 24 | |
53bbfa9e IM |
25 | /* USER_HZ period (usecs): */ |
26 | unsigned long tick_usec = TICK_USEC; | |
27 | ||
28 | /* ACTHZ period (nsecs): */ | |
29 | unsigned long tick_nsec; | |
7dffa3c6 | 30 | |
ea7cf49a | 31 | static u64 tick_length; |
53bbfa9e IM |
32 | static u64 tick_length_base; |
33 | ||
34 | static struct hrtimer leap_timer; | |
35 | ||
bbd12676 | 36 | #define MAX_TICKADJ 500LL /* usecs */ |
53bbfa9e | 37 | #define MAX_TICKADJ_SCALED \ |
bbd12676 | 38 | (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ) |
4c7ee8de | 39 | |
40 | /* | |
41 | * phase-lock loop variables | |
42 | */ | |
53bbfa9e IM |
43 | |
44 | /* | |
45 | * clock synchronization status | |
46 | * | |
47 | * (TIME_ERROR prevents overwriting the CMOS clock) | |
48 | */ | |
49 | static int time_state = TIME_OK; | |
50 | ||
51 | /* clock status bits: */ | |
8357929e | 52 | static int time_status = STA_UNSYNC; |
53bbfa9e IM |
53 | |
54 | /* TAI offset (secs): */ | |
55 | static long time_tai; | |
56 | ||
57 | /* time adjustment (nsecs): */ | |
58 | static s64 time_offset; | |
59 | ||
60 | /* pll time constant: */ | |
61 | static long time_constant = 2; | |
62 | ||
63 | /* maximum error (usecs): */ | |
1f5b8f8a | 64 | static long time_maxerror = NTP_PHASE_LIMIT; |
53bbfa9e IM |
65 | |
66 | /* estimated error (usecs): */ | |
1f5b8f8a | 67 | static long time_esterror = NTP_PHASE_LIMIT; |
53bbfa9e IM |
68 | |
69 | /* frequency offset (scaled nsecs/secs): */ | |
70 | static s64 time_freq; | |
71 | ||
72 | /* time at last adjustment (secs): */ | |
73 | static long time_reftime; | |
74 | ||
e1292ba1 | 75 | static long time_adjust; |
53bbfa9e | 76 | |
069569e0 IM |
77 | /* constant (boot-param configurable) NTP tick adjustment (upscaled) */ |
78 | static s64 ntp_tick_adj; | |
53bbfa9e | 79 | |
025b40ab AG |
80 | #ifdef CONFIG_NTP_PPS |
81 | ||
82 | /* | |
83 | * The following variables are used when a pulse-per-second (PPS) signal | |
84 | * is available. They establish the engineering parameters of the clock | |
85 | * discipline loop when controlled by the PPS signal. | |
86 | */ | |
87 | #define PPS_VALID 10 /* PPS signal watchdog max (s) */ | |
88 | #define PPS_POPCORN 4 /* popcorn spike threshold (shift) */ | |
89 | #define PPS_INTMIN 2 /* min freq interval (s) (shift) */ | |
90 | #define PPS_INTMAX 8 /* max freq interval (s) (shift) */ | |
91 | #define PPS_INTCOUNT 4 /* number of consecutive good intervals to | |
92 | increase pps_shift or consecutive bad | |
93 | intervals to decrease it */ | |
94 | #define PPS_MAXWANDER 100000 /* max PPS freq wander (ns/s) */ | |
95 | ||
96 | static int pps_valid; /* signal watchdog counter */ | |
97 | static long pps_tf[3]; /* phase median filter */ | |
98 | static long pps_jitter; /* current jitter (ns) */ | |
99 | static struct timespec pps_fbase; /* beginning of the last freq interval */ | |
100 | static int pps_shift; /* current interval duration (s) (shift) */ | |
101 | static int pps_intcnt; /* interval counter */ | |
102 | static s64 pps_freq; /* frequency offset (scaled ns/s) */ | |
103 | static long pps_stabil; /* current stability (scaled ns/s) */ | |
104 | ||
105 | /* | |
106 | * PPS signal quality monitors | |
107 | */ | |
108 | static long pps_calcnt; /* calibration intervals */ | |
109 | static long pps_jitcnt; /* jitter limit exceeded */ | |
110 | static long pps_stbcnt; /* stability limit exceeded */ | |
111 | static long pps_errcnt; /* calibration errors */ | |
112 | ||
113 | ||
114 | /* PPS kernel consumer compensates the whole phase error immediately. | |
115 | * Otherwise, reduce the offset by a fixed factor times the time constant. | |
116 | */ | |
117 | static inline s64 ntp_offset_chunk(s64 offset) | |
118 | { | |
119 | if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) | |
120 | return offset; | |
121 | else | |
122 | return shift_right(offset, SHIFT_PLL + time_constant); | |
123 | } | |
124 | ||
125 | static inline void pps_reset_freq_interval(void) | |
126 | { | |
127 | /* the PPS calibration interval may end | |
128 | surprisingly early */ | |
129 | pps_shift = PPS_INTMIN; | |
130 | pps_intcnt = 0; | |
131 | } | |
132 | ||
133 | /** | |
134 | * pps_clear - Clears the PPS state variables | |
135 | * | |
136 | * Must be called while holding a write on the xtime_lock | |
137 | */ | |
138 | static inline void pps_clear(void) | |
139 | { | |
140 | pps_reset_freq_interval(); | |
141 | pps_tf[0] = 0; | |
142 | pps_tf[1] = 0; | |
143 | pps_tf[2] = 0; | |
144 | pps_fbase.tv_sec = pps_fbase.tv_nsec = 0; | |
145 | pps_freq = 0; | |
146 | } | |
147 | ||
148 | /* Decrease pps_valid to indicate that another second has passed since | |
149 | * the last PPS signal. When it reaches 0, indicate that PPS signal is | |
150 | * missing. | |
151 | * | |
152 | * Must be called while holding a write on the xtime_lock | |
153 | */ | |
154 | static inline void pps_dec_valid(void) | |
155 | { | |
156 | if (pps_valid > 0) | |
157 | pps_valid--; | |
158 | else { | |
159 | time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | | |
160 | STA_PPSWANDER | STA_PPSERROR); | |
161 | pps_clear(); | |
162 | } | |
163 | } | |
164 | ||
165 | static inline void pps_set_freq(s64 freq) | |
166 | { | |
167 | pps_freq = freq; | |
168 | } | |
169 | ||
170 | static inline int is_error_status(int status) | |
171 | { | |
172 | return (time_status & (STA_UNSYNC|STA_CLOCKERR)) | |
173 | /* PPS signal lost when either PPS time or | |
174 | * PPS frequency synchronization requested | |
175 | */ | |
176 | || ((time_status & (STA_PPSFREQ|STA_PPSTIME)) | |
177 | && !(time_status & STA_PPSSIGNAL)) | |
178 | /* PPS jitter exceeded when | |
179 | * PPS time synchronization requested */ | |
180 | || ((time_status & (STA_PPSTIME|STA_PPSJITTER)) | |
181 | == (STA_PPSTIME|STA_PPSJITTER)) | |
182 | /* PPS wander exceeded or calibration error when | |
183 | * PPS frequency synchronization requested | |
184 | */ | |
185 | || ((time_status & STA_PPSFREQ) | |
186 | && (time_status & (STA_PPSWANDER|STA_PPSERROR))); | |
187 | } | |
188 | ||
189 | static inline void pps_fill_timex(struct timex *txc) | |
190 | { | |
191 | txc->ppsfreq = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) * | |
192 | PPM_SCALE_INV, NTP_SCALE_SHIFT); | |
193 | txc->jitter = pps_jitter; | |
194 | if (!(time_status & STA_NANO)) | |
195 | txc->jitter /= NSEC_PER_USEC; | |
196 | txc->shift = pps_shift; | |
197 | txc->stabil = pps_stabil; | |
198 | txc->jitcnt = pps_jitcnt; | |
199 | txc->calcnt = pps_calcnt; | |
200 | txc->errcnt = pps_errcnt; | |
201 | txc->stbcnt = pps_stbcnt; | |
202 | } | |
203 | ||
204 | #else /* !CONFIG_NTP_PPS */ | |
205 | ||
206 | static inline s64 ntp_offset_chunk(s64 offset) | |
207 | { | |
208 | return shift_right(offset, SHIFT_PLL + time_constant); | |
209 | } | |
210 | ||
211 | static inline void pps_reset_freq_interval(void) {} | |
212 | static inline void pps_clear(void) {} | |
213 | static inline void pps_dec_valid(void) {} | |
214 | static inline void pps_set_freq(s64 freq) {} | |
215 | ||
216 | static inline int is_error_status(int status) | |
217 | { | |
218 | return status & (STA_UNSYNC|STA_CLOCKERR); | |
219 | } | |
220 | ||
221 | static inline void pps_fill_timex(struct timex *txc) | |
222 | { | |
223 | /* PPS is not implemented, so these are zero */ | |
224 | txc->ppsfreq = 0; | |
225 | txc->jitter = 0; | |
226 | txc->shift = 0; | |
227 | txc->stabil = 0; | |
228 | txc->jitcnt = 0; | |
229 | txc->calcnt = 0; | |
230 | txc->errcnt = 0; | |
231 | txc->stbcnt = 0; | |
232 | } | |
233 | ||
234 | #endif /* CONFIG_NTP_PPS */ | |
235 | ||
8357929e JS |
236 | |
237 | /** | |
238 | * ntp_synced - Returns 1 if the NTP status is not UNSYNC | |
239 | * | |
240 | */ | |
241 | static inline int ntp_synced(void) | |
242 | { | |
243 | return !(time_status & STA_UNSYNC); | |
244 | } | |
245 | ||
246 | ||
53bbfa9e IM |
247 | /* |
248 | * NTP methods: | |
249 | */ | |
4c7ee8de | 250 | |
9ce616aa IM |
251 | /* |
252 | * Update (tick_length, tick_length_base, tick_nsec), based | |
253 | * on (tick_usec, ntp_tick_adj, time_freq): | |
254 | */ | |
70bc42f9 AB |
255 | static void ntp_update_frequency(void) |
256 | { | |
9ce616aa | 257 | u64 second_length; |
bc26c31d | 258 | u64 new_base; |
9ce616aa IM |
259 | |
260 | second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) | |
261 | << NTP_SCALE_SHIFT; | |
262 | ||
069569e0 | 263 | second_length += ntp_tick_adj; |
9ce616aa | 264 | second_length += time_freq; |
70bc42f9 | 265 | |
9ce616aa | 266 | tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT; |
bc26c31d | 267 | new_base = div_u64(second_length, NTP_INTERVAL_FREQ); |
fdcedf7b | 268 | |
269 | /* | |
270 | * Don't wait for the next second_overflow, apply | |
bc26c31d | 271 | * the change to the tick length immediately: |
fdcedf7b | 272 | */ |
bc26c31d IM |
273 | tick_length += new_base - tick_length_base; |
274 | tick_length_base = new_base; | |
70bc42f9 AB |
275 | } |
276 | ||
478b7aab | 277 | static inline s64 ntp_update_offset_fll(s64 offset64, long secs) |
f939890b IM |
278 | { |
279 | time_status &= ~STA_MODE; | |
280 | ||
281 | if (secs < MINSEC) | |
478b7aab | 282 | return 0; |
f939890b IM |
283 | |
284 | if (!(time_status & STA_FLL) && (secs <= MAXSEC)) | |
478b7aab | 285 | return 0; |
f939890b | 286 | |
f939890b IM |
287 | time_status |= STA_MODE; |
288 | ||
478b7aab | 289 | return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs); |
f939890b IM |
290 | } |
291 | ||
ee9851b2 RZ |
292 | static void ntp_update_offset(long offset) |
293 | { | |
ee9851b2 | 294 | s64 freq_adj; |
f939890b IM |
295 | s64 offset64; |
296 | long secs; | |
ee9851b2 RZ |
297 | |
298 | if (!(time_status & STA_PLL)) | |
299 | return; | |
300 | ||
eea83d89 | 301 | if (!(time_status & STA_NANO)) |
9f14f669 | 302 | offset *= NSEC_PER_USEC; |
ee9851b2 RZ |
303 | |
304 | /* | |
305 | * Scale the phase adjustment and | |
306 | * clamp to the operating range. | |
307 | */ | |
9f14f669 RZ |
308 | offset = min(offset, MAXPHASE); |
309 | offset = max(offset, -MAXPHASE); | |
ee9851b2 RZ |
310 | |
311 | /* | |
312 | * Select how the frequency is to be controlled | |
313 | * and in which mode (PLL or FLL). | |
314 | */ | |
7e1b5847 | 315 | secs = get_seconds() - time_reftime; |
10dd31a7 | 316 | if (unlikely(time_status & STA_FREQHOLD)) |
c7986acb IM |
317 | secs = 0; |
318 | ||
7e1b5847 | 319 | time_reftime = get_seconds(); |
ee9851b2 | 320 | |
f939890b | 321 | offset64 = offset; |
8af3c153 | 322 | freq_adj = ntp_update_offset_fll(offset64, secs); |
f939890b | 323 | |
8af3c153 ML |
324 | /* |
325 | * Clamp update interval to reduce PLL gain with low | |
326 | * sampling rate (e.g. intermittent network connection) | |
327 | * to avoid instability. | |
328 | */ | |
329 | if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant))) | |
330 | secs = 1 << (SHIFT_PLL + 1 + time_constant); | |
331 | ||
332 | freq_adj += (offset64 * secs) << | |
333 | (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant)); | |
f939890b IM |
334 | |
335 | freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED); | |
336 | ||
337 | time_freq = max(freq_adj, -MAXFREQ_SCALED); | |
338 | ||
339 | time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ); | |
ee9851b2 RZ |
340 | } |
341 | ||
b0ee7556 RZ |
342 | /** |
343 | * ntp_clear - Clears the NTP state variables | |
344 | * | |
345 | * Must be called while holding a write on the xtime_lock | |
346 | */ | |
347 | void ntp_clear(void) | |
348 | { | |
53bbfa9e IM |
349 | time_adjust = 0; /* stop active adjtime() */ |
350 | time_status |= STA_UNSYNC; | |
351 | time_maxerror = NTP_PHASE_LIMIT; | |
352 | time_esterror = NTP_PHASE_LIMIT; | |
b0ee7556 RZ |
353 | |
354 | ntp_update_frequency(); | |
355 | ||
53bbfa9e IM |
356 | tick_length = tick_length_base; |
357 | time_offset = 0; | |
025b40ab AG |
358 | |
359 | /* Clear PPS state variables */ | |
360 | pps_clear(); | |
b0ee7556 RZ |
361 | } |
362 | ||
ea7cf49a JS |
363 | |
364 | u64 ntp_tick_length(void) | |
365 | { | |
366 | return tick_length; | |
367 | } | |
368 | ||
369 | ||
4c7ee8de | 370 | /* |
7dffa3c6 RZ |
371 | * Leap second processing. If in leap-insert state at the end of the |
372 | * day, the system clock is set back one second; if in leap-delete | |
373 | * state, the system clock is set ahead one second. | |
4c7ee8de | 374 | */ |
7dffa3c6 | 375 | static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer) |
4c7ee8de | 376 | { |
7dffa3c6 | 377 | enum hrtimer_restart res = HRTIMER_NORESTART; |
4c7ee8de | 378 | |
ca109491 | 379 | write_seqlock(&xtime_lock); |
4c7ee8de | 380 | |
4c7ee8de | 381 | switch (time_state) { |
382 | case TIME_OK: | |
4c7ee8de | 383 | break; |
384 | case TIME_INS: | |
31089c13 | 385 | timekeeping_leap_insert(-1); |
7dffa3c6 | 386 | time_state = TIME_OOP; |
53bbfa9e IM |
387 | printk(KERN_NOTICE |
388 | "Clock: inserting leap second 23:59:60 UTC\n"); | |
cc584b21 | 389 | hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC); |
7dffa3c6 | 390 | res = HRTIMER_RESTART; |
4c7ee8de | 391 | break; |
392 | case TIME_DEL: | |
31089c13 | 393 | timekeeping_leap_insert(1); |
7dffa3c6 | 394 | time_tai--; |
7dffa3c6 | 395 | time_state = TIME_WAIT; |
53bbfa9e IM |
396 | printk(KERN_NOTICE |
397 | "Clock: deleting leap second 23:59:59 UTC\n"); | |
4c7ee8de | 398 | break; |
399 | case TIME_OOP: | |
153b5d05 | 400 | time_tai++; |
4c7ee8de | 401 | time_state = TIME_WAIT; |
7dffa3c6 | 402 | /* fall through */ |
4c7ee8de | 403 | case TIME_WAIT: |
404 | if (!(time_status & (STA_INS | STA_DEL))) | |
ee9851b2 | 405 | time_state = TIME_OK; |
7dffa3c6 RZ |
406 | break; |
407 | } | |
7dffa3c6 | 408 | |
ca109491 | 409 | write_sequnlock(&xtime_lock); |
7dffa3c6 RZ |
410 | |
411 | return res; | |
412 | } | |
413 | ||
414 | /* | |
415 | * this routine handles the overflow of the microsecond field | |
416 | * | |
417 | * The tricky bits of code to handle the accurate clock support | |
418 | * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. | |
419 | * They were originally developed for SUN and DEC kernels. | |
420 | * All the kudos should go to Dave for this stuff. | |
421 | */ | |
422 | void second_overflow(void) | |
423 | { | |
39854fe8 | 424 | s64 delta; |
7dffa3c6 RZ |
425 | |
426 | /* Bump the maxerror field */ | |
427 | time_maxerror += MAXFREQ / NSEC_PER_USEC; | |
428 | if (time_maxerror > NTP_PHASE_LIMIT) { | |
429 | time_maxerror = NTP_PHASE_LIMIT; | |
430 | time_status |= STA_UNSYNC; | |
4c7ee8de | 431 | } |
432 | ||
025b40ab | 433 | /* Compute the phase adjustment for the next second */ |
39854fe8 IM |
434 | tick_length = tick_length_base; |
435 | ||
025b40ab | 436 | delta = ntp_offset_chunk(time_offset); |
39854fe8 IM |
437 | time_offset -= delta; |
438 | tick_length += delta; | |
4c7ee8de | 439 | |
025b40ab AG |
440 | /* Check PPS signal */ |
441 | pps_dec_valid(); | |
442 | ||
3c972c24 IM |
443 | if (!time_adjust) |
444 | return; | |
445 | ||
446 | if (time_adjust > MAX_TICKADJ) { | |
447 | time_adjust -= MAX_TICKADJ; | |
448 | tick_length += MAX_TICKADJ_SCALED; | |
449 | return; | |
4c7ee8de | 450 | } |
3c972c24 IM |
451 | |
452 | if (time_adjust < -MAX_TICKADJ) { | |
453 | time_adjust += MAX_TICKADJ; | |
454 | tick_length -= MAX_TICKADJ_SCALED; | |
455 | return; | |
456 | } | |
457 | ||
458 | tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ) | |
459 | << NTP_SCALE_SHIFT; | |
460 | time_adjust = 0; | |
4c7ee8de | 461 | } |
462 | ||
82644459 | 463 | #ifdef CONFIG_GENERIC_CMOS_UPDATE |
4c7ee8de | 464 | |
82644459 TG |
465 | /* Disable the cmos update - used by virtualization and embedded */ |
466 | int no_sync_cmos_clock __read_mostly; | |
467 | ||
eb3f938f | 468 | static void sync_cmos_clock(struct work_struct *work); |
82644459 | 469 | |
eb3f938f | 470 | static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock); |
82644459 | 471 | |
eb3f938f | 472 | static void sync_cmos_clock(struct work_struct *work) |
82644459 TG |
473 | { |
474 | struct timespec now, next; | |
475 | int fail = 1; | |
476 | ||
477 | /* | |
478 | * If we have an externally synchronized Linux clock, then update | |
479 | * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be | |
480 | * called as close as possible to 500 ms before the new second starts. | |
481 | * This code is run on a timer. If the clock is set, that timer | |
482 | * may not expire at the correct time. Thus, we adjust... | |
483 | */ | |
53bbfa9e | 484 | if (!ntp_synced()) { |
82644459 TG |
485 | /* |
486 | * Not synced, exit, do not restart a timer (if one is | |
487 | * running, let it run out). | |
488 | */ | |
489 | return; | |
53bbfa9e | 490 | } |
82644459 TG |
491 | |
492 | getnstimeofday(&now); | |
fa6a1a55 | 493 | if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) |
82644459 TG |
494 | fail = update_persistent_clock(now); |
495 | ||
4ff4b9e1 | 496 | next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2); |
82644459 TG |
497 | if (next.tv_nsec <= 0) |
498 | next.tv_nsec += NSEC_PER_SEC; | |
499 | ||
500 | if (!fail) | |
501 | next.tv_sec = 659; | |
502 | else | |
503 | next.tv_sec = 0; | |
504 | ||
505 | if (next.tv_nsec >= NSEC_PER_SEC) { | |
506 | next.tv_sec++; | |
507 | next.tv_nsec -= NSEC_PER_SEC; | |
508 | } | |
eb3f938f | 509 | schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next)); |
82644459 TG |
510 | } |
511 | ||
512 | static void notify_cmos_timer(void) | |
4c7ee8de | 513 | { |
298a5df4 | 514 | if (!no_sync_cmos_clock) |
eb3f938f | 515 | schedule_delayed_work(&sync_cmos_work, 0); |
4c7ee8de | 516 | } |
517 | ||
82644459 TG |
518 | #else |
519 | static inline void notify_cmos_timer(void) { } | |
520 | #endif | |
521 | ||
e9629165 IM |
522 | /* |
523 | * Start the leap seconds timer: | |
524 | */ | |
525 | static inline void ntp_start_leap_timer(struct timespec *ts) | |
526 | { | |
527 | long now = ts->tv_sec; | |
528 | ||
529 | if (time_status & STA_INS) { | |
530 | time_state = TIME_INS; | |
531 | now += 86400 - now % 86400; | |
532 | hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS); | |
533 | ||
534 | return; | |
535 | } | |
536 | ||
537 | if (time_status & STA_DEL) { | |
538 | time_state = TIME_DEL; | |
539 | now += 86400 - (now + 1) % 86400; | |
540 | hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS); | |
541 | } | |
542 | } | |
80f22571 IM |
543 | |
544 | /* | |
545 | * Propagate a new txc->status value into the NTP state: | |
546 | */ | |
547 | static inline void process_adj_status(struct timex *txc, struct timespec *ts) | |
548 | { | |
80f22571 IM |
549 | if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) { |
550 | time_state = TIME_OK; | |
551 | time_status = STA_UNSYNC; | |
025b40ab AG |
552 | /* restart PPS frequency calibration */ |
553 | pps_reset_freq_interval(); | |
80f22571 | 554 | } |
80f22571 IM |
555 | |
556 | /* | |
557 | * If we turn on PLL adjustments then reset the | |
558 | * reference time to current time. | |
559 | */ | |
560 | if (!(time_status & STA_PLL) && (txc->status & STA_PLL)) | |
7e1b5847 | 561 | time_reftime = get_seconds(); |
80f22571 | 562 | |
a2a5ac86 JS |
563 | /* only set allowed bits */ |
564 | time_status &= STA_RONLY; | |
80f22571 IM |
565 | time_status |= txc->status & ~STA_RONLY; |
566 | ||
567 | switch (time_state) { | |
568 | case TIME_OK: | |
e9629165 | 569 | ntp_start_leap_timer(ts); |
80f22571 IM |
570 | break; |
571 | case TIME_INS: | |
572 | case TIME_DEL: | |
573 | time_state = TIME_OK; | |
e9629165 | 574 | ntp_start_leap_timer(ts); |
80f22571 IM |
575 | case TIME_WAIT: |
576 | if (!(time_status & (STA_INS | STA_DEL))) | |
577 | time_state = TIME_OK; | |
578 | break; | |
579 | case TIME_OOP: | |
580 | hrtimer_restart(&leap_timer); | |
581 | break; | |
582 | } | |
583 | } | |
584 | /* | |
585 | * Called with the xtime lock held, so we can access and modify | |
586 | * all the global NTP state: | |
587 | */ | |
588 | static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts) | |
589 | { | |
590 | if (txc->modes & ADJ_STATUS) | |
591 | process_adj_status(txc, ts); | |
592 | ||
593 | if (txc->modes & ADJ_NANO) | |
594 | time_status |= STA_NANO; | |
e9629165 | 595 | |
80f22571 IM |
596 | if (txc->modes & ADJ_MICRO) |
597 | time_status &= ~STA_NANO; | |
598 | ||
599 | if (txc->modes & ADJ_FREQUENCY) { | |
2b9d1496 | 600 | time_freq = txc->freq * PPM_SCALE; |
80f22571 IM |
601 | time_freq = min(time_freq, MAXFREQ_SCALED); |
602 | time_freq = max(time_freq, -MAXFREQ_SCALED); | |
025b40ab AG |
603 | /* update pps_freq */ |
604 | pps_set_freq(time_freq); | |
80f22571 IM |
605 | } |
606 | ||
607 | if (txc->modes & ADJ_MAXERROR) | |
608 | time_maxerror = txc->maxerror; | |
e9629165 | 609 | |
80f22571 IM |
610 | if (txc->modes & ADJ_ESTERROR) |
611 | time_esterror = txc->esterror; | |
612 | ||
613 | if (txc->modes & ADJ_TIMECONST) { | |
614 | time_constant = txc->constant; | |
615 | if (!(time_status & STA_NANO)) | |
616 | time_constant += 4; | |
617 | time_constant = min(time_constant, (long)MAXTC); | |
618 | time_constant = max(time_constant, 0l); | |
619 | } | |
620 | ||
621 | if (txc->modes & ADJ_TAI && txc->constant > 0) | |
622 | time_tai = txc->constant; | |
623 | ||
624 | if (txc->modes & ADJ_OFFSET) | |
625 | ntp_update_offset(txc->offset); | |
e9629165 | 626 | |
80f22571 IM |
627 | if (txc->modes & ADJ_TICK) |
628 | tick_usec = txc->tick; | |
629 | ||
630 | if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET)) | |
631 | ntp_update_frequency(); | |
632 | } | |
633 | ||
53bbfa9e IM |
634 | /* |
635 | * adjtimex mainly allows reading (and writing, if superuser) of | |
4c7ee8de | 636 | * kernel time-keeping variables. used by xntpd. |
637 | */ | |
638 | int do_adjtimex(struct timex *txc) | |
639 | { | |
eea83d89 | 640 | struct timespec ts; |
4c7ee8de | 641 | int result; |
642 | ||
916c7a85 RZ |
643 | /* Validate the data before disabling interrupts */ |
644 | if (txc->modes & ADJ_ADJTIME) { | |
eea83d89 | 645 | /* singleshot must not be used with any other mode bits */ |
916c7a85 | 646 | if (!(txc->modes & ADJ_OFFSET_SINGLESHOT)) |
4c7ee8de | 647 | return -EINVAL; |
916c7a85 RZ |
648 | if (!(txc->modes & ADJ_OFFSET_READONLY) && |
649 | !capable(CAP_SYS_TIME)) | |
650 | return -EPERM; | |
651 | } else { | |
652 | /* In order to modify anything, you gotta be super-user! */ | |
653 | if (txc->modes && !capable(CAP_SYS_TIME)) | |
654 | return -EPERM; | |
655 | ||
53bbfa9e IM |
656 | /* |
657 | * if the quartz is off by more than 10% then | |
658 | * something is VERY wrong! | |
659 | */ | |
916c7a85 RZ |
660 | if (txc->modes & ADJ_TICK && |
661 | (txc->tick < 900000/USER_HZ || | |
662 | txc->tick > 1100000/USER_HZ)) | |
e9629165 | 663 | return -EINVAL; |
916c7a85 RZ |
664 | |
665 | if (txc->modes & ADJ_STATUS && time_state != TIME_OK) | |
666 | hrtimer_cancel(&leap_timer); | |
52bfb360 | 667 | } |
4c7ee8de | 668 | |
094aa188 RC |
669 | if (txc->modes & ADJ_SETOFFSET) { |
670 | struct timespec delta; | |
094aa188 RC |
671 | delta.tv_sec = txc->time.tv_sec; |
672 | delta.tv_nsec = txc->time.tv_usec; | |
4352d9d4 RC |
673 | if (!capable(CAP_SYS_TIME)) |
674 | return -EPERM; | |
094aa188 RC |
675 | if (!(txc->modes & ADJ_NANO)) |
676 | delta.tv_nsec *= 1000; | |
db1c1cce RC |
677 | result = timekeeping_inject_offset(&delta); |
678 | if (result) | |
679 | return result; | |
094aa188 RC |
680 | } |
681 | ||
7dffa3c6 RZ |
682 | getnstimeofday(&ts); |
683 | ||
4c7ee8de | 684 | write_seqlock_irq(&xtime_lock); |
4c7ee8de | 685 | |
916c7a85 RZ |
686 | if (txc->modes & ADJ_ADJTIME) { |
687 | long save_adjust = time_adjust; | |
688 | ||
689 | if (!(txc->modes & ADJ_OFFSET_READONLY)) { | |
690 | /* adjtime() is independent from ntp_adjtime() */ | |
691 | time_adjust = txc->offset; | |
692 | ntp_update_frequency(); | |
693 | } | |
694 | txc->offset = save_adjust; | |
e9629165 | 695 | } else { |
ee9851b2 | 696 | |
e9629165 IM |
697 | /* If there are input parameters, then process them: */ |
698 | if (txc->modes) | |
699 | process_adjtimex_modes(txc, &ts); | |
eea83d89 | 700 | |
e9629165 | 701 | txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ, |
916c7a85 | 702 | NTP_SCALE_SHIFT); |
e9629165 IM |
703 | if (!(time_status & STA_NANO)) |
704 | txc->offset /= NSEC_PER_USEC; | |
705 | } | |
916c7a85 | 706 | |
eea83d89 | 707 | result = time_state; /* mostly `TIME_OK' */ |
025b40ab AG |
708 | /* check for errors */ |
709 | if (is_error_status(time_status)) | |
4c7ee8de | 710 | result = TIME_ERROR; |
711 | ||
d40e944c | 712 | txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) * |
2b9d1496 | 713 | PPM_SCALE_INV, NTP_SCALE_SHIFT); |
4c7ee8de | 714 | txc->maxerror = time_maxerror; |
715 | txc->esterror = time_esterror; | |
716 | txc->status = time_status; | |
717 | txc->constant = time_constant; | |
70bc42f9 | 718 | txc->precision = 1; |
074b3b87 | 719 | txc->tolerance = MAXFREQ_SCALED / PPM_SCALE; |
4c7ee8de | 720 | txc->tick = tick_usec; |
153b5d05 | 721 | txc->tai = time_tai; |
4c7ee8de | 722 | |
025b40ab AG |
723 | /* fill PPS status fields */ |
724 | pps_fill_timex(txc); | |
e9629165 | 725 | |
4c7ee8de | 726 | write_sequnlock_irq(&xtime_lock); |
ee9851b2 | 727 | |
eea83d89 RZ |
728 | txc->time.tv_sec = ts.tv_sec; |
729 | txc->time.tv_usec = ts.tv_nsec; | |
730 | if (!(time_status & STA_NANO)) | |
731 | txc->time.tv_usec /= NSEC_PER_USEC; | |
ee9851b2 | 732 | |
82644459 | 733 | notify_cmos_timer(); |
ee9851b2 RZ |
734 | |
735 | return result; | |
4c7ee8de | 736 | } |
10a398d0 | 737 | |
025b40ab AG |
738 | #ifdef CONFIG_NTP_PPS |
739 | ||
740 | /* actually struct pps_normtime is good old struct timespec, but it is | |
741 | * semantically different (and it is the reason why it was invented): | |
742 | * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] | |
743 | * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */ | |
744 | struct pps_normtime { | |
745 | __kernel_time_t sec; /* seconds */ | |
746 | long nsec; /* nanoseconds */ | |
747 | }; | |
748 | ||
749 | /* normalize the timestamp so that nsec is in the | |
750 | ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */ | |
751 | static inline struct pps_normtime pps_normalize_ts(struct timespec ts) | |
752 | { | |
753 | struct pps_normtime norm = { | |
754 | .sec = ts.tv_sec, | |
755 | .nsec = ts.tv_nsec | |
756 | }; | |
757 | ||
758 | if (norm.nsec > (NSEC_PER_SEC >> 1)) { | |
759 | norm.nsec -= NSEC_PER_SEC; | |
760 | norm.sec++; | |
761 | } | |
762 | ||
763 | return norm; | |
764 | } | |
765 | ||
766 | /* get current phase correction and jitter */ | |
767 | static inline long pps_phase_filter_get(long *jitter) | |
768 | { | |
769 | *jitter = pps_tf[0] - pps_tf[1]; | |
770 | if (*jitter < 0) | |
771 | *jitter = -*jitter; | |
772 | ||
773 | /* TODO: test various filters */ | |
774 | return pps_tf[0]; | |
775 | } | |
776 | ||
777 | /* add the sample to the phase filter */ | |
778 | static inline void pps_phase_filter_add(long err) | |
779 | { | |
780 | pps_tf[2] = pps_tf[1]; | |
781 | pps_tf[1] = pps_tf[0]; | |
782 | pps_tf[0] = err; | |
783 | } | |
784 | ||
785 | /* decrease frequency calibration interval length. | |
786 | * It is halved after four consecutive unstable intervals. | |
787 | */ | |
788 | static inline void pps_dec_freq_interval(void) | |
789 | { | |
790 | if (--pps_intcnt <= -PPS_INTCOUNT) { | |
791 | pps_intcnt = -PPS_INTCOUNT; | |
792 | if (pps_shift > PPS_INTMIN) { | |
793 | pps_shift--; | |
794 | pps_intcnt = 0; | |
795 | } | |
796 | } | |
797 | } | |
798 | ||
799 | /* increase frequency calibration interval length. | |
800 | * It is doubled after four consecutive stable intervals. | |
801 | */ | |
802 | static inline void pps_inc_freq_interval(void) | |
803 | { | |
804 | if (++pps_intcnt >= PPS_INTCOUNT) { | |
805 | pps_intcnt = PPS_INTCOUNT; | |
806 | if (pps_shift < PPS_INTMAX) { | |
807 | pps_shift++; | |
808 | pps_intcnt = 0; | |
809 | } | |
810 | } | |
811 | } | |
812 | ||
813 | /* update clock frequency based on MONOTONIC_RAW clock PPS signal | |
814 | * timestamps | |
815 | * | |
816 | * At the end of the calibration interval the difference between the | |
817 | * first and last MONOTONIC_RAW clock timestamps divided by the length | |
818 | * of the interval becomes the frequency update. If the interval was | |
819 | * too long, the data are discarded. | |
820 | * Returns the difference between old and new frequency values. | |
821 | */ | |
822 | static long hardpps_update_freq(struct pps_normtime freq_norm) | |
823 | { | |
824 | long delta, delta_mod; | |
825 | s64 ftemp; | |
826 | ||
827 | /* check if the frequency interval was too long */ | |
828 | if (freq_norm.sec > (2 << pps_shift)) { | |
829 | time_status |= STA_PPSERROR; | |
830 | pps_errcnt++; | |
831 | pps_dec_freq_interval(); | |
832 | pr_err("hardpps: PPSERROR: interval too long - %ld s\n", | |
833 | freq_norm.sec); | |
834 | return 0; | |
835 | } | |
836 | ||
837 | /* here the raw frequency offset and wander (stability) is | |
838 | * calculated. If the wander is less than the wander threshold | |
839 | * the interval is increased; otherwise it is decreased. | |
840 | */ | |
841 | ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT, | |
842 | freq_norm.sec); | |
843 | delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT); | |
844 | pps_freq = ftemp; | |
845 | if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) { | |
846 | pr_warning("hardpps: PPSWANDER: change=%ld\n", delta); | |
847 | time_status |= STA_PPSWANDER; | |
848 | pps_stbcnt++; | |
849 | pps_dec_freq_interval(); | |
850 | } else { /* good sample */ | |
851 | pps_inc_freq_interval(); | |
852 | } | |
853 | ||
854 | /* the stability metric is calculated as the average of recent | |
855 | * frequency changes, but is used only for performance | |
856 | * monitoring | |
857 | */ | |
858 | delta_mod = delta; | |
859 | if (delta_mod < 0) | |
860 | delta_mod = -delta_mod; | |
861 | pps_stabil += (div_s64(((s64)delta_mod) << | |
862 | (NTP_SCALE_SHIFT - SHIFT_USEC), | |
863 | NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN; | |
864 | ||
865 | /* if enabled, the system clock frequency is updated */ | |
866 | if ((time_status & STA_PPSFREQ) != 0 && | |
867 | (time_status & STA_FREQHOLD) == 0) { | |
868 | time_freq = pps_freq; | |
869 | ntp_update_frequency(); | |
870 | } | |
871 | ||
872 | return delta; | |
873 | } | |
874 | ||
875 | /* correct REALTIME clock phase error against PPS signal */ | |
876 | static void hardpps_update_phase(long error) | |
877 | { | |
878 | long correction = -error; | |
879 | long jitter; | |
880 | ||
881 | /* add the sample to the median filter */ | |
882 | pps_phase_filter_add(correction); | |
883 | correction = pps_phase_filter_get(&jitter); | |
884 | ||
885 | /* Nominal jitter is due to PPS signal noise. If it exceeds the | |
886 | * threshold, the sample is discarded; otherwise, if so enabled, | |
887 | * the time offset is updated. | |
888 | */ | |
889 | if (jitter > (pps_jitter << PPS_POPCORN)) { | |
890 | pr_warning("hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", | |
891 | jitter, (pps_jitter << PPS_POPCORN)); | |
892 | time_status |= STA_PPSJITTER; | |
893 | pps_jitcnt++; | |
894 | } else if (time_status & STA_PPSTIME) { | |
895 | /* correct the time using the phase offset */ | |
896 | time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT, | |
897 | NTP_INTERVAL_FREQ); | |
898 | /* cancel running adjtime() */ | |
899 | time_adjust = 0; | |
900 | } | |
901 | /* update jitter */ | |
902 | pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN; | |
903 | } | |
904 | ||
905 | /* | |
906 | * hardpps() - discipline CPU clock oscillator to external PPS signal | |
907 | * | |
908 | * This routine is called at each PPS signal arrival in order to | |
909 | * discipline the CPU clock oscillator to the PPS signal. It takes two | |
910 | * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former | |
911 | * is used to correct clock phase error and the latter is used to | |
912 | * correct the frequency. | |
913 | * | |
914 | * This code is based on David Mills's reference nanokernel | |
915 | * implementation. It was mostly rewritten but keeps the same idea. | |
916 | */ | |
917 | void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) | |
918 | { | |
919 | struct pps_normtime pts_norm, freq_norm; | |
920 | unsigned long flags; | |
921 | ||
922 | pts_norm = pps_normalize_ts(*phase_ts); | |
923 | ||
924 | write_seqlock_irqsave(&xtime_lock, flags); | |
925 | ||
926 | /* clear the error bits, they will be set again if needed */ | |
927 | time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); | |
928 | ||
929 | /* indicate signal presence */ | |
930 | time_status |= STA_PPSSIGNAL; | |
931 | pps_valid = PPS_VALID; | |
932 | ||
933 | /* when called for the first time, | |
934 | * just start the frequency interval */ | |
935 | if (unlikely(pps_fbase.tv_sec == 0)) { | |
936 | pps_fbase = *raw_ts; | |
937 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
938 | return; | |
939 | } | |
940 | ||
941 | /* ok, now we have a base for frequency calculation */ | |
942 | freq_norm = pps_normalize_ts(timespec_sub(*raw_ts, pps_fbase)); | |
943 | ||
944 | /* check that the signal is in the range | |
945 | * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */ | |
946 | if ((freq_norm.sec == 0) || | |
947 | (freq_norm.nsec > MAXFREQ * freq_norm.sec) || | |
948 | (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) { | |
949 | time_status |= STA_PPSJITTER; | |
950 | /* restart the frequency calibration interval */ | |
951 | pps_fbase = *raw_ts; | |
952 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
953 | pr_err("hardpps: PPSJITTER: bad pulse\n"); | |
954 | return; | |
955 | } | |
956 | ||
957 | /* signal is ok */ | |
958 | ||
959 | /* check if the current frequency interval is finished */ | |
960 | if (freq_norm.sec >= (1 << pps_shift)) { | |
961 | pps_calcnt++; | |
962 | /* restart the frequency calibration interval */ | |
963 | pps_fbase = *raw_ts; | |
964 | hardpps_update_freq(freq_norm); | |
965 | } | |
966 | ||
967 | hardpps_update_phase(pts_norm.nsec); | |
968 | ||
969 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
970 | } | |
971 | EXPORT_SYMBOL(hardpps); | |
972 | ||
973 | #endif /* CONFIG_NTP_PPS */ | |
974 | ||
10a398d0 RZ |
975 | static int __init ntp_tick_adj_setup(char *str) |
976 | { | |
977 | ntp_tick_adj = simple_strtol(str, NULL, 0); | |
069569e0 IM |
978 | ntp_tick_adj <<= NTP_SCALE_SHIFT; |
979 | ||
10a398d0 RZ |
980 | return 1; |
981 | } | |
982 | ||
983 | __setup("ntp_tick_adj=", ntp_tick_adj_setup); | |
7dffa3c6 RZ |
984 | |
985 | void __init ntp_init(void) | |
986 | { | |
987 | ntp_clear(); | |
988 | hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS); | |
989 | leap_timer.function = ntp_leap_second; | |
990 | } |