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Commit | Line | Data |
---|---|---|
4c7ee8de | 1 | /* |
4c7ee8de JS |
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> |
023f333a | 18 | #include <linux/rtc.h> |
4c7ee8de | 19 | |
e2830b5c | 20 | #include "tick-internal.h" |
aa6f9c59 | 21 | #include "ntp_internal.h" |
e2830b5c | 22 | |
b0ee7556 | 23 | /* |
53bbfa9e | 24 | * NTP timekeeping variables: |
b0ee7556 | 25 | */ |
b0ee7556 | 26 | |
a6c0c943 | 27 | DEFINE_RAW_SPINLOCK(ntp_lock); |
bd331268 JS |
28 | |
29 | ||
53bbfa9e IM |
30 | /* USER_HZ period (usecs): */ |
31 | unsigned long tick_usec = TICK_USEC; | |
32 | ||
02ab20ae | 33 | /* SHIFTED_HZ period (nsecs): */ |
53bbfa9e | 34 | unsigned long tick_nsec; |
7dffa3c6 | 35 | |
ea7cf49a | 36 | static u64 tick_length; |
53bbfa9e IM |
37 | static u64 tick_length_base; |
38 | ||
bbd12676 | 39 | #define MAX_TICKADJ 500LL /* usecs */ |
53bbfa9e | 40 | #define MAX_TICKADJ_SCALED \ |
bbd12676 | 41 | (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ) |
4c7ee8de JS |
42 | |
43 | /* | |
44 | * phase-lock loop variables | |
45 | */ | |
53bbfa9e IM |
46 | |
47 | /* | |
48 | * clock synchronization status | |
49 | * | |
50 | * (TIME_ERROR prevents overwriting the CMOS clock) | |
51 | */ | |
52 | static int time_state = TIME_OK; | |
53 | ||
54 | /* clock status bits: */ | |
8357929e | 55 | static int time_status = STA_UNSYNC; |
53bbfa9e | 56 | |
53bbfa9e IM |
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 | * | |
bd331268 | 136 | * Must be called while holding a write on the ntp_lock |
025b40ab AG |
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 | * | |
bd331268 | 152 | * Must be called while holding a write on the ntp_lock |
025b40ab AG |
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 JS |
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 | ||
a078c6d0 | 289 | return div64_long(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 | |
b0ee7556 RZ |
344 | */ |
345 | void ntp_clear(void) | |
346 | { | |
bd331268 JS |
347 | unsigned long flags; |
348 | ||
a6c0c943 | 349 | raw_spin_lock_irqsave(&ntp_lock, flags); |
bd331268 | 350 | |
53bbfa9e IM |
351 | time_adjust = 0; /* stop active adjtime() */ |
352 | time_status |= STA_UNSYNC; | |
353 | time_maxerror = NTP_PHASE_LIMIT; | |
354 | time_esterror = NTP_PHASE_LIMIT; | |
b0ee7556 RZ |
355 | |
356 | ntp_update_frequency(); | |
357 | ||
53bbfa9e IM |
358 | tick_length = tick_length_base; |
359 | time_offset = 0; | |
025b40ab AG |
360 | |
361 | /* Clear PPS state variables */ | |
362 | pps_clear(); | |
a6c0c943 | 363 | raw_spin_unlock_irqrestore(&ntp_lock, flags); |
bd331268 | 364 | |
b0ee7556 RZ |
365 | } |
366 | ||
ea7cf49a JS |
367 | |
368 | u64 ntp_tick_length(void) | |
369 | { | |
bd331268 JS |
370 | unsigned long flags; |
371 | s64 ret; | |
372 | ||
a6c0c943 | 373 | raw_spin_lock_irqsave(&ntp_lock, flags); |
bd331268 | 374 | ret = tick_length; |
a6c0c943 | 375 | raw_spin_unlock_irqrestore(&ntp_lock, flags); |
bd331268 | 376 | return ret; |
ea7cf49a JS |
377 | } |
378 | ||
379 | ||
4c7ee8de | 380 | /* |
6b43ae8a JS |
381 | * this routine handles the overflow of the microsecond field |
382 | * | |
383 | * The tricky bits of code to handle the accurate clock support | |
384 | * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. | |
385 | * They were originally developed for SUN and DEC kernels. | |
386 | * All the kudos should go to Dave for this stuff. | |
387 | * | |
388 | * Also handles leap second processing, and returns leap offset | |
4c7ee8de | 389 | */ |
6b43ae8a | 390 | int second_overflow(unsigned long secs) |
4c7ee8de | 391 | { |
6b43ae8a | 392 | s64 delta; |
bd331268 | 393 | int leap = 0; |
6b43ae8a | 394 | unsigned long flags; |
4c7ee8de | 395 | |
a6c0c943 | 396 | raw_spin_lock_irqsave(&ntp_lock, flags); |
6b43ae8a JS |
397 | |
398 | /* | |
399 | * Leap second processing. If in leap-insert state at the end of the | |
400 | * day, the system clock is set back one second; if in leap-delete | |
401 | * state, the system clock is set ahead one second. | |
402 | */ | |
4c7ee8de JS |
403 | switch (time_state) { |
404 | case TIME_OK: | |
6b43ae8a JS |
405 | if (time_status & STA_INS) |
406 | time_state = TIME_INS; | |
407 | else if (time_status & STA_DEL) | |
408 | time_state = TIME_DEL; | |
4c7ee8de JS |
409 | break; |
410 | case TIME_INS: | |
6b1859db JS |
411 | if (!(time_status & STA_INS)) |
412 | time_state = TIME_OK; | |
413 | else if (secs % 86400 == 0) { | |
6b43ae8a JS |
414 | leap = -1; |
415 | time_state = TIME_OOP; | |
416 | printk(KERN_NOTICE | |
417 | "Clock: inserting leap second 23:59:60 UTC\n"); | |
418 | } | |
4c7ee8de JS |
419 | break; |
420 | case TIME_DEL: | |
6b1859db JS |
421 | if (!(time_status & STA_DEL)) |
422 | time_state = TIME_OK; | |
423 | else if ((secs + 1) % 86400 == 0) { | |
6b43ae8a | 424 | leap = 1; |
6b43ae8a JS |
425 | time_state = TIME_WAIT; |
426 | printk(KERN_NOTICE | |
427 | "Clock: deleting leap second 23:59:59 UTC\n"); | |
428 | } | |
4c7ee8de JS |
429 | break; |
430 | case TIME_OOP: | |
431 | time_state = TIME_WAIT; | |
6b43ae8a JS |
432 | break; |
433 | ||
4c7ee8de JS |
434 | case TIME_WAIT: |
435 | if (!(time_status & (STA_INS | STA_DEL))) | |
ee9851b2 | 436 | time_state = TIME_OK; |
7dffa3c6 RZ |
437 | break; |
438 | } | |
bd331268 | 439 | |
7dffa3c6 RZ |
440 | |
441 | /* Bump the maxerror field */ | |
442 | time_maxerror += MAXFREQ / NSEC_PER_USEC; | |
443 | if (time_maxerror > NTP_PHASE_LIMIT) { | |
444 | time_maxerror = NTP_PHASE_LIMIT; | |
445 | time_status |= STA_UNSYNC; | |
4c7ee8de JS |
446 | } |
447 | ||
025b40ab | 448 | /* Compute the phase adjustment for the next second */ |
39854fe8 IM |
449 | tick_length = tick_length_base; |
450 | ||
025b40ab | 451 | delta = ntp_offset_chunk(time_offset); |
39854fe8 IM |
452 | time_offset -= delta; |
453 | tick_length += delta; | |
4c7ee8de | 454 | |
025b40ab AG |
455 | /* Check PPS signal */ |
456 | pps_dec_valid(); | |
457 | ||
3c972c24 | 458 | if (!time_adjust) |
bd331268 | 459 | goto out; |
3c972c24 IM |
460 | |
461 | if (time_adjust > MAX_TICKADJ) { | |
462 | time_adjust -= MAX_TICKADJ; | |
463 | tick_length += MAX_TICKADJ_SCALED; | |
bd331268 | 464 | goto out; |
4c7ee8de | 465 | } |
3c972c24 IM |
466 | |
467 | if (time_adjust < -MAX_TICKADJ) { | |
468 | time_adjust += MAX_TICKADJ; | |
469 | tick_length -= MAX_TICKADJ_SCALED; | |
bd331268 | 470 | goto out; |
3c972c24 IM |
471 | } |
472 | ||
473 | tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ) | |
474 | << NTP_SCALE_SHIFT; | |
475 | time_adjust = 0; | |
6b43ae8a | 476 | |
bd331268 | 477 | out: |
a6c0c943 | 478 | raw_spin_unlock_irqrestore(&ntp_lock, flags); |
6b43ae8a JS |
479 | |
480 | return leap; | |
4c7ee8de JS |
481 | } |
482 | ||
023f333a | 483 | #if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC) |
eb3f938f | 484 | static void sync_cmos_clock(struct work_struct *work); |
82644459 | 485 | |
eb3f938f | 486 | static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock); |
82644459 | 487 | |
eb3f938f | 488 | static void sync_cmos_clock(struct work_struct *work) |
82644459 TG |
489 | { |
490 | struct timespec now, next; | |
491 | int fail = 1; | |
492 | ||
493 | /* | |
494 | * If we have an externally synchronized Linux clock, then update | |
495 | * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be | |
496 | * called as close as possible to 500 ms before the new second starts. | |
497 | * This code is run on a timer. If the clock is set, that timer | |
498 | * may not expire at the correct time. Thus, we adjust... | |
499 | */ | |
53bbfa9e | 500 | if (!ntp_synced()) { |
82644459 TG |
501 | /* |
502 | * Not synced, exit, do not restart a timer (if one is | |
503 | * running, let it run out). | |
504 | */ | |
505 | return; | |
53bbfa9e | 506 | } |
82644459 TG |
507 | |
508 | getnstimeofday(&now); | |
023f333a | 509 | if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) { |
84e345e4 PB |
510 | struct timespec adjust = now; |
511 | ||
023f333a | 512 | fail = -ENODEV; |
84e345e4 PB |
513 | if (persistent_clock_is_local) |
514 | adjust.tv_sec -= (sys_tz.tz_minuteswest * 60); | |
023f333a | 515 | #ifdef CONFIG_GENERIC_CMOS_UPDATE |
84e345e4 | 516 | fail = update_persistent_clock(adjust); |
023f333a JG |
517 | #endif |
518 | #ifdef CONFIG_RTC_SYSTOHC | |
519 | if (fail == -ENODEV) | |
84e345e4 | 520 | fail = rtc_set_ntp_time(adjust); |
023f333a JG |
521 | #endif |
522 | } | |
82644459 | 523 | |
4ff4b9e1 | 524 | next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2); |
82644459 TG |
525 | if (next.tv_nsec <= 0) |
526 | next.tv_nsec += NSEC_PER_SEC; | |
527 | ||
023f333a | 528 | if (!fail || fail == -ENODEV) |
82644459 TG |
529 | next.tv_sec = 659; |
530 | else | |
531 | next.tv_sec = 0; | |
532 | ||
533 | if (next.tv_nsec >= NSEC_PER_SEC) { | |
534 | next.tv_sec++; | |
535 | next.tv_nsec -= NSEC_PER_SEC; | |
536 | } | |
eb3f938f | 537 | schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next)); |
82644459 TG |
538 | } |
539 | ||
540 | static void notify_cmos_timer(void) | |
4c7ee8de | 541 | { |
335dd858 | 542 | schedule_delayed_work(&sync_cmos_work, 0); |
4c7ee8de JS |
543 | } |
544 | ||
82644459 TG |
545 | #else |
546 | static inline void notify_cmos_timer(void) { } | |
547 | #endif | |
548 | ||
80f22571 IM |
549 | |
550 | /* | |
551 | * Propagate a new txc->status value into the NTP state: | |
552 | */ | |
553 | static inline void process_adj_status(struct timex *txc, struct timespec *ts) | |
554 | { | |
80f22571 IM |
555 | if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) { |
556 | time_state = TIME_OK; | |
557 | time_status = STA_UNSYNC; | |
025b40ab AG |
558 | /* restart PPS frequency calibration */ |
559 | pps_reset_freq_interval(); | |
80f22571 | 560 | } |
80f22571 IM |
561 | |
562 | /* | |
563 | * If we turn on PLL adjustments then reset the | |
564 | * reference time to current time. | |
565 | */ | |
566 | if (!(time_status & STA_PLL) && (txc->status & STA_PLL)) | |
7e1b5847 | 567 | time_reftime = get_seconds(); |
80f22571 | 568 | |
a2a5ac86 JS |
569 | /* only set allowed bits */ |
570 | time_status &= STA_RONLY; | |
80f22571 | 571 | time_status |= txc->status & ~STA_RONLY; |
80f22571 | 572 | } |
cd5398be | 573 | |
80f22571 | 574 | /* |
cd5398be | 575 | * Called with ntp_lock held, so we can access and modify |
80f22571 IM |
576 | * all the global NTP state: |
577 | */ | |
cc244dda JS |
578 | static inline void process_adjtimex_modes(struct timex *txc, |
579 | struct timespec *ts, | |
580 | s32 *time_tai) | |
80f22571 IM |
581 | { |
582 | if (txc->modes & ADJ_STATUS) | |
583 | process_adj_status(txc, ts); | |
584 | ||
585 | if (txc->modes & ADJ_NANO) | |
586 | time_status |= STA_NANO; | |
e9629165 | 587 | |
80f22571 IM |
588 | if (txc->modes & ADJ_MICRO) |
589 | time_status &= ~STA_NANO; | |
590 | ||
591 | if (txc->modes & ADJ_FREQUENCY) { | |
2b9d1496 | 592 | time_freq = txc->freq * PPM_SCALE; |
80f22571 IM |
593 | time_freq = min(time_freq, MAXFREQ_SCALED); |
594 | time_freq = max(time_freq, -MAXFREQ_SCALED); | |
025b40ab AG |
595 | /* update pps_freq */ |
596 | pps_set_freq(time_freq); | |
80f22571 IM |
597 | } |
598 | ||
599 | if (txc->modes & ADJ_MAXERROR) | |
600 | time_maxerror = txc->maxerror; | |
e9629165 | 601 | |
80f22571 IM |
602 | if (txc->modes & ADJ_ESTERROR) |
603 | time_esterror = txc->esterror; | |
604 | ||
605 | if (txc->modes & ADJ_TIMECONST) { | |
606 | time_constant = txc->constant; | |
607 | if (!(time_status & STA_NANO)) | |
608 | time_constant += 4; | |
609 | time_constant = min(time_constant, (long)MAXTC); | |
610 | time_constant = max(time_constant, 0l); | |
611 | } | |
612 | ||
613 | if (txc->modes & ADJ_TAI && txc->constant > 0) | |
cc244dda | 614 | *time_tai = txc->constant; |
80f22571 IM |
615 | |
616 | if (txc->modes & ADJ_OFFSET) | |
617 | ntp_update_offset(txc->offset); | |
e9629165 | 618 | |
80f22571 IM |
619 | if (txc->modes & ADJ_TICK) |
620 | tick_usec = txc->tick; | |
621 | ||
622 | if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET)) | |
623 | ntp_update_frequency(); | |
624 | } | |
625 | ||
ad460967 JS |
626 | |
627 | ||
628 | /** | |
629 | * ntp_validate_timex - Ensures the timex is ok for use in do_adjtimex | |
4c7ee8de | 630 | */ |
ad460967 | 631 | int ntp_validate_timex(struct timex *txc) |
4c7ee8de | 632 | { |
916c7a85 | 633 | if (txc->modes & ADJ_ADJTIME) { |
eea83d89 | 634 | /* singleshot must not be used with any other mode bits */ |
916c7a85 | 635 | if (!(txc->modes & ADJ_OFFSET_SINGLESHOT)) |
4c7ee8de | 636 | return -EINVAL; |
916c7a85 RZ |
637 | if (!(txc->modes & ADJ_OFFSET_READONLY) && |
638 | !capable(CAP_SYS_TIME)) | |
639 | return -EPERM; | |
640 | } else { | |
641 | /* In order to modify anything, you gotta be super-user! */ | |
642 | if (txc->modes && !capable(CAP_SYS_TIME)) | |
643 | return -EPERM; | |
53bbfa9e IM |
644 | /* |
645 | * if the quartz is off by more than 10% then | |
646 | * something is VERY wrong! | |
647 | */ | |
916c7a85 RZ |
648 | if (txc->modes & ADJ_TICK && |
649 | (txc->tick < 900000/USER_HZ || | |
650 | txc->tick > 1100000/USER_HZ)) | |
e9629165 | 651 | return -EINVAL; |
52bfb360 | 652 | } |
4c7ee8de | 653 | |
ad460967 JS |
654 | if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME))) |
655 | return -EPERM; | |
656 | ||
657 | return 0; | |
658 | } | |
659 | ||
660 | ||
661 | /* | |
662 | * adjtimex mainly allows reading (and writing, if superuser) of | |
663 | * kernel time-keeping variables. used by xntpd. | |
664 | */ | |
87ace39b | 665 | int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai) |
ad460967 | 666 | { |
ad460967 JS |
667 | int result; |
668 | ||
a6c0c943 | 669 | raw_spin_lock_irq(&ntp_lock); |
4c7ee8de | 670 | |
916c7a85 RZ |
671 | if (txc->modes & ADJ_ADJTIME) { |
672 | long save_adjust = time_adjust; | |
673 | ||
674 | if (!(txc->modes & ADJ_OFFSET_READONLY)) { | |
675 | /* adjtime() is independent from ntp_adjtime() */ | |
676 | time_adjust = txc->offset; | |
677 | ntp_update_frequency(); | |
678 | } | |
679 | txc->offset = save_adjust; | |
e9629165 | 680 | } else { |
ee9851b2 | 681 | |
e9629165 IM |
682 | /* If there are input parameters, then process them: */ |
683 | if (txc->modes) | |
87ace39b | 684 | process_adjtimex_modes(txc, ts, time_tai); |
eea83d89 | 685 | |
e9629165 | 686 | txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ, |
916c7a85 | 687 | NTP_SCALE_SHIFT); |
e9629165 IM |
688 | if (!(time_status & STA_NANO)) |
689 | txc->offset /= NSEC_PER_USEC; | |
690 | } | |
916c7a85 | 691 | |
eea83d89 | 692 | result = time_state; /* mostly `TIME_OK' */ |
025b40ab AG |
693 | /* check for errors */ |
694 | if (is_error_status(time_status)) | |
4c7ee8de JS |
695 | result = TIME_ERROR; |
696 | ||
d40e944c | 697 | txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) * |
2b9d1496 | 698 | PPM_SCALE_INV, NTP_SCALE_SHIFT); |
4c7ee8de JS |
699 | txc->maxerror = time_maxerror; |
700 | txc->esterror = time_esterror; | |
701 | txc->status = time_status; | |
702 | txc->constant = time_constant; | |
70bc42f9 | 703 | txc->precision = 1; |
074b3b87 | 704 | txc->tolerance = MAXFREQ_SCALED / PPM_SCALE; |
4c7ee8de | 705 | txc->tick = tick_usec; |
87ace39b | 706 | txc->tai = *time_tai; |
4c7ee8de | 707 | |
025b40ab AG |
708 | /* fill PPS status fields */ |
709 | pps_fill_timex(txc); | |
e9629165 | 710 | |
a6c0c943 | 711 | raw_spin_unlock_irq(&ntp_lock); |
ee9851b2 | 712 | |
87ace39b JS |
713 | txc->time.tv_sec = ts->tv_sec; |
714 | txc->time.tv_usec = ts->tv_nsec; | |
eea83d89 RZ |
715 | if (!(time_status & STA_NANO)) |
716 | txc->time.tv_usec /= NSEC_PER_USEC; | |
ee9851b2 | 717 | |
82644459 | 718 | notify_cmos_timer(); |
ee9851b2 RZ |
719 | |
720 | return result; | |
4c7ee8de | 721 | } |
10a398d0 | 722 | |
025b40ab AG |
723 | #ifdef CONFIG_NTP_PPS |
724 | ||
725 | /* actually struct pps_normtime is good old struct timespec, but it is | |
726 | * semantically different (and it is the reason why it was invented): | |
727 | * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] | |
728 | * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */ | |
729 | struct pps_normtime { | |
730 | __kernel_time_t sec; /* seconds */ | |
731 | long nsec; /* nanoseconds */ | |
732 | }; | |
733 | ||
734 | /* normalize the timestamp so that nsec is in the | |
735 | ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */ | |
736 | static inline struct pps_normtime pps_normalize_ts(struct timespec ts) | |
737 | { | |
738 | struct pps_normtime norm = { | |
739 | .sec = ts.tv_sec, | |
740 | .nsec = ts.tv_nsec | |
741 | }; | |
742 | ||
743 | if (norm.nsec > (NSEC_PER_SEC >> 1)) { | |
744 | norm.nsec -= NSEC_PER_SEC; | |
745 | norm.sec++; | |
746 | } | |
747 | ||
748 | return norm; | |
749 | } | |
750 | ||
751 | /* get current phase correction and jitter */ | |
752 | static inline long pps_phase_filter_get(long *jitter) | |
753 | { | |
754 | *jitter = pps_tf[0] - pps_tf[1]; | |
755 | if (*jitter < 0) | |
756 | *jitter = -*jitter; | |
757 | ||
758 | /* TODO: test various filters */ | |
759 | return pps_tf[0]; | |
760 | } | |
761 | ||
762 | /* add the sample to the phase filter */ | |
763 | static inline void pps_phase_filter_add(long err) | |
764 | { | |
765 | pps_tf[2] = pps_tf[1]; | |
766 | pps_tf[1] = pps_tf[0]; | |
767 | pps_tf[0] = err; | |
768 | } | |
769 | ||
770 | /* decrease frequency calibration interval length. | |
771 | * It is halved after four consecutive unstable intervals. | |
772 | */ | |
773 | static inline void pps_dec_freq_interval(void) | |
774 | { | |
775 | if (--pps_intcnt <= -PPS_INTCOUNT) { | |
776 | pps_intcnt = -PPS_INTCOUNT; | |
777 | if (pps_shift > PPS_INTMIN) { | |
778 | pps_shift--; | |
779 | pps_intcnt = 0; | |
780 | } | |
781 | } | |
782 | } | |
783 | ||
784 | /* increase frequency calibration interval length. | |
785 | * It is doubled after four consecutive stable intervals. | |
786 | */ | |
787 | static inline void pps_inc_freq_interval(void) | |
788 | { | |
789 | if (++pps_intcnt >= PPS_INTCOUNT) { | |
790 | pps_intcnt = PPS_INTCOUNT; | |
791 | if (pps_shift < PPS_INTMAX) { | |
792 | pps_shift++; | |
793 | pps_intcnt = 0; | |
794 | } | |
795 | } | |
796 | } | |
797 | ||
798 | /* update clock frequency based on MONOTONIC_RAW clock PPS signal | |
799 | * timestamps | |
800 | * | |
801 | * At the end of the calibration interval the difference between the | |
802 | * first and last MONOTONIC_RAW clock timestamps divided by the length | |
803 | * of the interval becomes the frequency update. If the interval was | |
804 | * too long, the data are discarded. | |
805 | * Returns the difference between old and new frequency values. | |
806 | */ | |
807 | static long hardpps_update_freq(struct pps_normtime freq_norm) | |
808 | { | |
809 | long delta, delta_mod; | |
810 | s64 ftemp; | |
811 | ||
812 | /* check if the frequency interval was too long */ | |
813 | if (freq_norm.sec > (2 << pps_shift)) { | |
814 | time_status |= STA_PPSERROR; | |
815 | pps_errcnt++; | |
816 | pps_dec_freq_interval(); | |
817 | pr_err("hardpps: PPSERROR: interval too long - %ld s\n", | |
818 | freq_norm.sec); | |
819 | return 0; | |
820 | } | |
821 | ||
822 | /* here the raw frequency offset and wander (stability) is | |
823 | * calculated. If the wander is less than the wander threshold | |
824 | * the interval is increased; otherwise it is decreased. | |
825 | */ | |
826 | ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT, | |
827 | freq_norm.sec); | |
828 | delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT); | |
829 | pps_freq = ftemp; | |
830 | if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) { | |
831 | pr_warning("hardpps: PPSWANDER: change=%ld\n", delta); | |
832 | time_status |= STA_PPSWANDER; | |
833 | pps_stbcnt++; | |
834 | pps_dec_freq_interval(); | |
835 | } else { /* good sample */ | |
836 | pps_inc_freq_interval(); | |
837 | } | |
838 | ||
839 | /* the stability metric is calculated as the average of recent | |
840 | * frequency changes, but is used only for performance | |
841 | * monitoring | |
842 | */ | |
843 | delta_mod = delta; | |
844 | if (delta_mod < 0) | |
845 | delta_mod = -delta_mod; | |
846 | pps_stabil += (div_s64(((s64)delta_mod) << | |
847 | (NTP_SCALE_SHIFT - SHIFT_USEC), | |
848 | NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN; | |
849 | ||
850 | /* if enabled, the system clock frequency is updated */ | |
851 | if ((time_status & STA_PPSFREQ) != 0 && | |
852 | (time_status & STA_FREQHOLD) == 0) { | |
853 | time_freq = pps_freq; | |
854 | ntp_update_frequency(); | |
855 | } | |
856 | ||
857 | return delta; | |
858 | } | |
859 | ||
860 | /* correct REALTIME clock phase error against PPS signal */ | |
861 | static void hardpps_update_phase(long error) | |
862 | { | |
863 | long correction = -error; | |
864 | long jitter; | |
865 | ||
866 | /* add the sample to the median filter */ | |
867 | pps_phase_filter_add(correction); | |
868 | correction = pps_phase_filter_get(&jitter); | |
869 | ||
870 | /* Nominal jitter is due to PPS signal noise. If it exceeds the | |
871 | * threshold, the sample is discarded; otherwise, if so enabled, | |
872 | * the time offset is updated. | |
873 | */ | |
874 | if (jitter > (pps_jitter << PPS_POPCORN)) { | |
875 | pr_warning("hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", | |
876 | jitter, (pps_jitter << PPS_POPCORN)); | |
877 | time_status |= STA_PPSJITTER; | |
878 | pps_jitcnt++; | |
879 | } else if (time_status & STA_PPSTIME) { | |
880 | /* correct the time using the phase offset */ | |
881 | time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT, | |
882 | NTP_INTERVAL_FREQ); | |
883 | /* cancel running adjtime() */ | |
884 | time_adjust = 0; | |
885 | } | |
886 | /* update jitter */ | |
887 | pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN; | |
888 | } | |
889 | ||
890 | /* | |
aa6f9c59 | 891 | * __hardpps() - discipline CPU clock oscillator to external PPS signal |
025b40ab AG |
892 | * |
893 | * This routine is called at each PPS signal arrival in order to | |
894 | * discipline the CPU clock oscillator to the PPS signal. It takes two | |
895 | * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former | |
896 | * is used to correct clock phase error and the latter is used to | |
897 | * correct the frequency. | |
898 | * | |
899 | * This code is based on David Mills's reference nanokernel | |
900 | * implementation. It was mostly rewritten but keeps the same idea. | |
901 | */ | |
aa6f9c59 | 902 | void __hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) |
025b40ab AG |
903 | { |
904 | struct pps_normtime pts_norm, freq_norm; | |
905 | unsigned long flags; | |
906 | ||
907 | pts_norm = pps_normalize_ts(*phase_ts); | |
908 | ||
a6c0c943 | 909 | raw_spin_lock_irqsave(&ntp_lock, flags); |
025b40ab AG |
910 | |
911 | /* clear the error bits, they will be set again if needed */ | |
912 | time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); | |
913 | ||
914 | /* indicate signal presence */ | |
915 | time_status |= STA_PPSSIGNAL; | |
916 | pps_valid = PPS_VALID; | |
917 | ||
918 | /* when called for the first time, | |
919 | * just start the frequency interval */ | |
920 | if (unlikely(pps_fbase.tv_sec == 0)) { | |
921 | pps_fbase = *raw_ts; | |
a6c0c943 | 922 | raw_spin_unlock_irqrestore(&ntp_lock, flags); |
025b40ab AG |
923 | return; |
924 | } | |
925 | ||
926 | /* ok, now we have a base for frequency calculation */ | |
927 | freq_norm = pps_normalize_ts(timespec_sub(*raw_ts, pps_fbase)); | |
928 | ||
929 | /* check that the signal is in the range | |
930 | * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */ | |
931 | if ((freq_norm.sec == 0) || | |
932 | (freq_norm.nsec > MAXFREQ * freq_norm.sec) || | |
933 | (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) { | |
934 | time_status |= STA_PPSJITTER; | |
935 | /* restart the frequency calibration interval */ | |
936 | pps_fbase = *raw_ts; | |
a6c0c943 | 937 | raw_spin_unlock_irqrestore(&ntp_lock, flags); |
025b40ab AG |
938 | pr_err("hardpps: PPSJITTER: bad pulse\n"); |
939 | return; | |
940 | } | |
941 | ||
942 | /* signal is ok */ | |
943 | ||
944 | /* check if the current frequency interval is finished */ | |
945 | if (freq_norm.sec >= (1 << pps_shift)) { | |
946 | pps_calcnt++; | |
947 | /* restart the frequency calibration interval */ | |
948 | pps_fbase = *raw_ts; | |
949 | hardpps_update_freq(freq_norm); | |
950 | } | |
951 | ||
952 | hardpps_update_phase(pts_norm.nsec); | |
953 | ||
a6c0c943 | 954 | raw_spin_unlock_irqrestore(&ntp_lock, flags); |
025b40ab | 955 | } |
025b40ab AG |
956 | #endif /* CONFIG_NTP_PPS */ |
957 | ||
10a398d0 RZ |
958 | static int __init ntp_tick_adj_setup(char *str) |
959 | { | |
960 | ntp_tick_adj = simple_strtol(str, NULL, 0); | |
069569e0 IM |
961 | ntp_tick_adj <<= NTP_SCALE_SHIFT; |
962 | ||
10a398d0 RZ |
963 | return 1; |
964 | } | |
965 | ||
966 | __setup("ntp_tick_adj=", ntp_tick_adj_setup); | |
7dffa3c6 RZ |
967 | |
968 | void __init ntp_init(void) | |
969 | { | |
970 | ntp_clear(); | |
7dffa3c6 | 971 | } |