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 | |
bd331268 JS |
25 | DEFINE_SPINLOCK(ntp_lock); |
26 | ||
27 | ||
53bbfa9e IM |
28 | /* USER_HZ period (usecs): */ |
29 | unsigned long tick_usec = TICK_USEC; | |
30 | ||
02ab20ae | 31 | /* SHIFTED_HZ period (nsecs): */ |
53bbfa9e | 32 | unsigned long tick_nsec; |
7dffa3c6 | 33 | |
ea7cf49a | 34 | static u64 tick_length; |
53bbfa9e IM |
35 | static u64 tick_length_base; |
36 | ||
bbd12676 | 37 | #define MAX_TICKADJ 500LL /* usecs */ |
53bbfa9e | 38 | #define MAX_TICKADJ_SCALED \ |
bbd12676 | 39 | (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ) |
4c7ee8de | 40 | |
41 | /* | |
42 | * phase-lock loop variables | |
43 | */ | |
53bbfa9e IM |
44 | |
45 | /* | |
46 | * clock synchronization status | |
47 | * | |
48 | * (TIME_ERROR prevents overwriting the CMOS clock) | |
49 | */ | |
50 | static int time_state = TIME_OK; | |
51 | ||
52 | /* clock status bits: */ | |
8357929e | 53 | static int time_status = STA_UNSYNC; |
53bbfa9e IM |
54 | |
55 | /* TAI offset (secs): */ | |
56 | static long time_tai; | |
57 | ||
58 | /* time adjustment (nsecs): */ | |
59 | static s64 time_offset; | |
60 | ||
61 | /* pll time constant: */ | |
62 | static long time_constant = 2; | |
63 | ||
64 | /* maximum error (usecs): */ | |
1f5b8f8a | 65 | static long time_maxerror = NTP_PHASE_LIMIT; |
53bbfa9e IM |
66 | |
67 | /* estimated error (usecs): */ | |
1f5b8f8a | 68 | static long time_esterror = NTP_PHASE_LIMIT; |
53bbfa9e IM |
69 | |
70 | /* frequency offset (scaled nsecs/secs): */ | |
71 | static s64 time_freq; | |
72 | ||
73 | /* time at last adjustment (secs): */ | |
74 | static long time_reftime; | |
75 | ||
e1292ba1 | 76 | static long time_adjust; |
53bbfa9e | 77 | |
069569e0 IM |
78 | /* constant (boot-param configurable) NTP tick adjustment (upscaled) */ |
79 | static s64 ntp_tick_adj; | |
53bbfa9e | 80 | |
025b40ab AG |
81 | #ifdef CONFIG_NTP_PPS |
82 | ||
83 | /* | |
84 | * The following variables are used when a pulse-per-second (PPS) signal | |
85 | * is available. They establish the engineering parameters of the clock | |
86 | * discipline loop when controlled by the PPS signal. | |
87 | */ | |
88 | #define PPS_VALID 10 /* PPS signal watchdog max (s) */ | |
89 | #define PPS_POPCORN 4 /* popcorn spike threshold (shift) */ | |
90 | #define PPS_INTMIN 2 /* min freq interval (s) (shift) */ | |
91 | #define PPS_INTMAX 8 /* max freq interval (s) (shift) */ | |
92 | #define PPS_INTCOUNT 4 /* number of consecutive good intervals to | |
93 | increase pps_shift or consecutive bad | |
94 | intervals to decrease it */ | |
95 | #define PPS_MAXWANDER 100000 /* max PPS freq wander (ns/s) */ | |
96 | ||
97 | static int pps_valid; /* signal watchdog counter */ | |
98 | static long pps_tf[3]; /* phase median filter */ | |
99 | static long pps_jitter; /* current jitter (ns) */ | |
100 | static struct timespec pps_fbase; /* beginning of the last freq interval */ | |
101 | static int pps_shift; /* current interval duration (s) (shift) */ | |
102 | static int pps_intcnt; /* interval counter */ | |
103 | static s64 pps_freq; /* frequency offset (scaled ns/s) */ | |
104 | static long pps_stabil; /* current stability (scaled ns/s) */ | |
105 | ||
106 | /* | |
107 | * PPS signal quality monitors | |
108 | */ | |
109 | static long pps_calcnt; /* calibration intervals */ | |
110 | static long pps_jitcnt; /* jitter limit exceeded */ | |
111 | static long pps_stbcnt; /* stability limit exceeded */ | |
112 | static long pps_errcnt; /* calibration errors */ | |
113 | ||
114 | ||
115 | /* PPS kernel consumer compensates the whole phase error immediately. | |
116 | * Otherwise, reduce the offset by a fixed factor times the time constant. | |
117 | */ | |
118 | static inline s64 ntp_offset_chunk(s64 offset) | |
119 | { | |
120 | if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) | |
121 | return offset; | |
122 | else | |
123 | return shift_right(offset, SHIFT_PLL + time_constant); | |
124 | } | |
125 | ||
126 | static inline void pps_reset_freq_interval(void) | |
127 | { | |
128 | /* the PPS calibration interval may end | |
129 | surprisingly early */ | |
130 | pps_shift = PPS_INTMIN; | |
131 | pps_intcnt = 0; | |
132 | } | |
133 | ||
134 | /** | |
135 | * pps_clear - Clears the PPS state variables | |
136 | * | |
bd331268 | 137 | * Must be called while holding a write on the ntp_lock |
025b40ab AG |
138 | */ |
139 | static inline void pps_clear(void) | |
140 | { | |
141 | pps_reset_freq_interval(); | |
142 | pps_tf[0] = 0; | |
143 | pps_tf[1] = 0; | |
144 | pps_tf[2] = 0; | |
145 | pps_fbase.tv_sec = pps_fbase.tv_nsec = 0; | |
146 | pps_freq = 0; | |
147 | } | |
148 | ||
149 | /* Decrease pps_valid to indicate that another second has passed since | |
150 | * the last PPS signal. When it reaches 0, indicate that PPS signal is | |
151 | * missing. | |
152 | * | |
bd331268 | 153 | * Must be called while holding a write on the ntp_lock |
025b40ab AG |
154 | */ |
155 | static inline void pps_dec_valid(void) | |
156 | { | |
157 | if (pps_valid > 0) | |
158 | pps_valid--; | |
159 | else { | |
160 | time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | | |
161 | STA_PPSWANDER | STA_PPSERROR); | |
162 | pps_clear(); | |
163 | } | |
164 | } | |
165 | ||
166 | static inline void pps_set_freq(s64 freq) | |
167 | { | |
168 | pps_freq = freq; | |
169 | } | |
170 | ||
171 | static inline int is_error_status(int status) | |
172 | { | |
173 | return (time_status & (STA_UNSYNC|STA_CLOCKERR)) | |
174 | /* PPS signal lost when either PPS time or | |
175 | * PPS frequency synchronization requested | |
176 | */ | |
177 | || ((time_status & (STA_PPSFREQ|STA_PPSTIME)) | |
178 | && !(time_status & STA_PPSSIGNAL)) | |
179 | /* PPS jitter exceeded when | |
180 | * PPS time synchronization requested */ | |
181 | || ((time_status & (STA_PPSTIME|STA_PPSJITTER)) | |
182 | == (STA_PPSTIME|STA_PPSJITTER)) | |
183 | /* PPS wander exceeded or calibration error when | |
184 | * PPS frequency synchronization requested | |
185 | */ | |
186 | || ((time_status & STA_PPSFREQ) | |
187 | && (time_status & (STA_PPSWANDER|STA_PPSERROR))); | |
188 | } | |
189 | ||
190 | static inline void pps_fill_timex(struct timex *txc) | |
191 | { | |
192 | txc->ppsfreq = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) * | |
193 | PPM_SCALE_INV, NTP_SCALE_SHIFT); | |
194 | txc->jitter = pps_jitter; | |
195 | if (!(time_status & STA_NANO)) | |
196 | txc->jitter /= NSEC_PER_USEC; | |
197 | txc->shift = pps_shift; | |
198 | txc->stabil = pps_stabil; | |
199 | txc->jitcnt = pps_jitcnt; | |
200 | txc->calcnt = pps_calcnt; | |
201 | txc->errcnt = pps_errcnt; | |
202 | txc->stbcnt = pps_stbcnt; | |
203 | } | |
204 | ||
205 | #else /* !CONFIG_NTP_PPS */ | |
206 | ||
207 | static inline s64 ntp_offset_chunk(s64 offset) | |
208 | { | |
209 | return shift_right(offset, SHIFT_PLL + time_constant); | |
210 | } | |
211 | ||
212 | static inline void pps_reset_freq_interval(void) {} | |
213 | static inline void pps_clear(void) {} | |
214 | static inline void pps_dec_valid(void) {} | |
215 | static inline void pps_set_freq(s64 freq) {} | |
216 | ||
217 | static inline int is_error_status(int status) | |
218 | { | |
219 | return status & (STA_UNSYNC|STA_CLOCKERR); | |
220 | } | |
221 | ||
222 | static inline void pps_fill_timex(struct timex *txc) | |
223 | { | |
224 | /* PPS is not implemented, so these are zero */ | |
225 | txc->ppsfreq = 0; | |
226 | txc->jitter = 0; | |
227 | txc->shift = 0; | |
228 | txc->stabil = 0; | |
229 | txc->jitcnt = 0; | |
230 | txc->calcnt = 0; | |
231 | txc->errcnt = 0; | |
232 | txc->stbcnt = 0; | |
233 | } | |
234 | ||
235 | #endif /* CONFIG_NTP_PPS */ | |
236 | ||
8357929e JS |
237 | |
238 | /** | |
239 | * ntp_synced - Returns 1 if the NTP status is not UNSYNC | |
240 | * | |
241 | */ | |
242 | static inline int ntp_synced(void) | |
243 | { | |
244 | return !(time_status & STA_UNSYNC); | |
245 | } | |
246 | ||
247 | ||
53bbfa9e IM |
248 | /* |
249 | * NTP methods: | |
250 | */ | |
4c7ee8de | 251 | |
9ce616aa IM |
252 | /* |
253 | * Update (tick_length, tick_length_base, tick_nsec), based | |
254 | * on (tick_usec, ntp_tick_adj, time_freq): | |
255 | */ | |
70bc42f9 AB |
256 | static void ntp_update_frequency(void) |
257 | { | |
9ce616aa | 258 | u64 second_length; |
bc26c31d | 259 | u64 new_base; |
9ce616aa IM |
260 | |
261 | second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) | |
262 | << NTP_SCALE_SHIFT; | |
263 | ||
069569e0 | 264 | second_length += ntp_tick_adj; |
9ce616aa | 265 | second_length += time_freq; |
70bc42f9 | 266 | |
9ce616aa | 267 | tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT; |
bc26c31d | 268 | new_base = div_u64(second_length, NTP_INTERVAL_FREQ); |
fdcedf7b | 269 | |
270 | /* | |
271 | * Don't wait for the next second_overflow, apply | |
bc26c31d | 272 | * the change to the tick length immediately: |
fdcedf7b | 273 | */ |
bc26c31d IM |
274 | tick_length += new_base - tick_length_base; |
275 | tick_length_base = new_base; | |
70bc42f9 AB |
276 | } |
277 | ||
478b7aab | 278 | static inline s64 ntp_update_offset_fll(s64 offset64, long secs) |
f939890b IM |
279 | { |
280 | time_status &= ~STA_MODE; | |
281 | ||
282 | if (secs < MINSEC) | |
478b7aab | 283 | return 0; |
f939890b IM |
284 | |
285 | if (!(time_status & STA_FLL) && (secs <= MAXSEC)) | |
478b7aab | 286 | return 0; |
f939890b | 287 | |
f939890b IM |
288 | time_status |= STA_MODE; |
289 | ||
a078c6d0 | 290 | return div64_long(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs); |
f939890b IM |
291 | } |
292 | ||
ee9851b2 RZ |
293 | static void ntp_update_offset(long offset) |
294 | { | |
ee9851b2 | 295 | s64 freq_adj; |
f939890b IM |
296 | s64 offset64; |
297 | long secs; | |
ee9851b2 RZ |
298 | |
299 | if (!(time_status & STA_PLL)) | |
300 | return; | |
301 | ||
eea83d89 | 302 | if (!(time_status & STA_NANO)) |
9f14f669 | 303 | offset *= NSEC_PER_USEC; |
ee9851b2 RZ |
304 | |
305 | /* | |
306 | * Scale the phase adjustment and | |
307 | * clamp to the operating range. | |
308 | */ | |
9f14f669 RZ |
309 | offset = min(offset, MAXPHASE); |
310 | offset = max(offset, -MAXPHASE); | |
ee9851b2 RZ |
311 | |
312 | /* | |
313 | * Select how the frequency is to be controlled | |
314 | * and in which mode (PLL or FLL). | |
315 | */ | |
7e1b5847 | 316 | secs = get_seconds() - time_reftime; |
10dd31a7 | 317 | if (unlikely(time_status & STA_FREQHOLD)) |
c7986acb IM |
318 | secs = 0; |
319 | ||
7e1b5847 | 320 | time_reftime = get_seconds(); |
ee9851b2 | 321 | |
f939890b | 322 | offset64 = offset; |
8af3c153 | 323 | freq_adj = ntp_update_offset_fll(offset64, secs); |
f939890b | 324 | |
8af3c153 ML |
325 | /* |
326 | * Clamp update interval to reduce PLL gain with low | |
327 | * sampling rate (e.g. intermittent network connection) | |
328 | * to avoid instability. | |
329 | */ | |
330 | if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant))) | |
331 | secs = 1 << (SHIFT_PLL + 1 + time_constant); | |
332 | ||
333 | freq_adj += (offset64 * secs) << | |
334 | (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant)); | |
f939890b IM |
335 | |
336 | freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED); | |
337 | ||
338 | time_freq = max(freq_adj, -MAXFREQ_SCALED); | |
339 | ||
340 | time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ); | |
ee9851b2 RZ |
341 | } |
342 | ||
b0ee7556 RZ |
343 | /** |
344 | * ntp_clear - Clears the NTP state variables | |
b0ee7556 RZ |
345 | */ |
346 | void ntp_clear(void) | |
347 | { | |
bd331268 JS |
348 | unsigned long flags; |
349 | ||
350 | spin_lock_irqsave(&ntp_lock, flags); | |
351 | ||
53bbfa9e IM |
352 | time_adjust = 0; /* stop active adjtime() */ |
353 | time_status |= STA_UNSYNC; | |
354 | time_maxerror = NTP_PHASE_LIMIT; | |
355 | time_esterror = NTP_PHASE_LIMIT; | |
b0ee7556 RZ |
356 | |
357 | ntp_update_frequency(); | |
358 | ||
53bbfa9e IM |
359 | tick_length = tick_length_base; |
360 | time_offset = 0; | |
025b40ab AG |
361 | |
362 | /* Clear PPS state variables */ | |
363 | pps_clear(); | |
bd331268 JS |
364 | spin_unlock_irqrestore(&ntp_lock, flags); |
365 | ||
b0ee7556 RZ |
366 | } |
367 | ||
ea7cf49a JS |
368 | |
369 | u64 ntp_tick_length(void) | |
370 | { | |
bd331268 JS |
371 | unsigned long flags; |
372 | s64 ret; | |
373 | ||
374 | spin_lock_irqsave(&ntp_lock, flags); | |
375 | ret = tick_length; | |
376 | spin_unlock_irqrestore(&ntp_lock, flags); | |
377 | return ret; | |
ea7cf49a JS |
378 | } |
379 | ||
380 | ||
4c7ee8de | 381 | /* |
6b43ae8a JS |
382 | * this routine handles the overflow of the microsecond field |
383 | * | |
384 | * The tricky bits of code to handle the accurate clock support | |
385 | * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. | |
386 | * They were originally developed for SUN and DEC kernels. | |
387 | * All the kudos should go to Dave for this stuff. | |
388 | * | |
389 | * Also handles leap second processing, and returns leap offset | |
4c7ee8de | 390 | */ |
6b43ae8a | 391 | int second_overflow(unsigned long secs) |
4c7ee8de | 392 | { |
6b43ae8a | 393 | s64 delta; |
bd331268 | 394 | int leap = 0; |
6b43ae8a | 395 | unsigned long flags; |
4c7ee8de | 396 | |
bd331268 | 397 | spin_lock_irqsave(&ntp_lock, flags); |
6b43ae8a JS |
398 | |
399 | /* | |
400 | * Leap second processing. If in leap-insert state at the end of the | |
401 | * day, the system clock is set back one second; if in leap-delete | |
402 | * state, the system clock is set ahead one second. | |
403 | */ | |
4c7ee8de | 404 | switch (time_state) { |
405 | case TIME_OK: | |
6b43ae8a JS |
406 | if (time_status & STA_INS) |
407 | time_state = TIME_INS; | |
408 | else if (time_status & STA_DEL) | |
409 | time_state = TIME_DEL; | |
4c7ee8de | 410 | break; |
411 | case TIME_INS: | |
6b1859db JS |
412 | if (!(time_status & STA_INS)) |
413 | time_state = TIME_OK; | |
414 | else if (secs % 86400 == 0) { | |
6b43ae8a JS |
415 | leap = -1; |
416 | time_state = TIME_OOP; | |
dd48d708 | 417 | time_tai++; |
6b43ae8a JS |
418 | printk(KERN_NOTICE |
419 | "Clock: inserting leap second 23:59:60 UTC\n"); | |
420 | } | |
4c7ee8de | 421 | break; |
422 | case TIME_DEL: | |
6b1859db JS |
423 | if (!(time_status & STA_DEL)) |
424 | time_state = TIME_OK; | |
425 | else if ((secs + 1) % 86400 == 0) { | |
6b43ae8a JS |
426 | leap = 1; |
427 | time_tai--; | |
428 | time_state = TIME_WAIT; | |
429 | printk(KERN_NOTICE | |
430 | "Clock: deleting leap second 23:59:59 UTC\n"); | |
431 | } | |
4c7ee8de | 432 | break; |
433 | case TIME_OOP: | |
434 | time_state = TIME_WAIT; | |
6b43ae8a JS |
435 | break; |
436 | ||
4c7ee8de | 437 | case TIME_WAIT: |
438 | if (!(time_status & (STA_INS | STA_DEL))) | |
ee9851b2 | 439 | time_state = TIME_OK; |
7dffa3c6 RZ |
440 | break; |
441 | } | |
bd331268 | 442 | |
7dffa3c6 RZ |
443 | |
444 | /* Bump the maxerror field */ | |
445 | time_maxerror += MAXFREQ / NSEC_PER_USEC; | |
446 | if (time_maxerror > NTP_PHASE_LIMIT) { | |
447 | time_maxerror = NTP_PHASE_LIMIT; | |
448 | time_status |= STA_UNSYNC; | |
4c7ee8de | 449 | } |
450 | ||
025b40ab | 451 | /* Compute the phase adjustment for the next second */ |
39854fe8 IM |
452 | tick_length = tick_length_base; |
453 | ||
025b40ab | 454 | delta = ntp_offset_chunk(time_offset); |
39854fe8 IM |
455 | time_offset -= delta; |
456 | tick_length += delta; | |
4c7ee8de | 457 | |
025b40ab AG |
458 | /* Check PPS signal */ |
459 | pps_dec_valid(); | |
460 | ||
3c972c24 | 461 | if (!time_adjust) |
bd331268 | 462 | goto out; |
3c972c24 IM |
463 | |
464 | if (time_adjust > MAX_TICKADJ) { | |
465 | time_adjust -= MAX_TICKADJ; | |
466 | tick_length += MAX_TICKADJ_SCALED; | |
bd331268 | 467 | goto out; |
4c7ee8de | 468 | } |
3c972c24 IM |
469 | |
470 | if (time_adjust < -MAX_TICKADJ) { | |
471 | time_adjust += MAX_TICKADJ; | |
472 | tick_length -= MAX_TICKADJ_SCALED; | |
bd331268 | 473 | goto out; |
3c972c24 IM |
474 | } |
475 | ||
476 | tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ) | |
477 | << NTP_SCALE_SHIFT; | |
478 | time_adjust = 0; | |
6b43ae8a | 479 | |
bd331268 JS |
480 | out: |
481 | spin_unlock_irqrestore(&ntp_lock, flags); | |
6b43ae8a JS |
482 | |
483 | return leap; | |
4c7ee8de | 484 | } |
485 | ||
82644459 | 486 | #ifdef CONFIG_GENERIC_CMOS_UPDATE |
4c7ee8de | 487 | |
eb3f938f | 488 | static void sync_cmos_clock(struct work_struct *work); |
82644459 | 489 | |
eb3f938f | 490 | static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock); |
82644459 | 491 | |
eb3f938f | 492 | static void sync_cmos_clock(struct work_struct *work) |
82644459 TG |
493 | { |
494 | struct timespec now, next; | |
495 | int fail = 1; | |
496 | ||
497 | /* | |
498 | * If we have an externally synchronized Linux clock, then update | |
499 | * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be | |
500 | * called as close as possible to 500 ms before the new second starts. | |
501 | * This code is run on a timer. If the clock is set, that timer | |
502 | * may not expire at the correct time. Thus, we adjust... | |
503 | */ | |
53bbfa9e | 504 | if (!ntp_synced()) { |
82644459 TG |
505 | /* |
506 | * Not synced, exit, do not restart a timer (if one is | |
507 | * running, let it run out). | |
508 | */ | |
509 | return; | |
53bbfa9e | 510 | } |
82644459 TG |
511 | |
512 | getnstimeofday(&now); | |
fa6a1a55 | 513 | if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) |
82644459 TG |
514 | fail = update_persistent_clock(now); |
515 | ||
4ff4b9e1 | 516 | next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2); |
82644459 TG |
517 | if (next.tv_nsec <= 0) |
518 | next.tv_nsec += NSEC_PER_SEC; | |
519 | ||
520 | if (!fail) | |
521 | next.tv_sec = 659; | |
522 | else | |
523 | next.tv_sec = 0; | |
524 | ||
525 | if (next.tv_nsec >= NSEC_PER_SEC) { | |
526 | next.tv_sec++; | |
527 | next.tv_nsec -= NSEC_PER_SEC; | |
528 | } | |
eb3f938f | 529 | schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next)); |
82644459 TG |
530 | } |
531 | ||
532 | static void notify_cmos_timer(void) | |
4c7ee8de | 533 | { |
335dd858 | 534 | schedule_delayed_work(&sync_cmos_work, 0); |
4c7ee8de | 535 | } |
536 | ||
82644459 TG |
537 | #else |
538 | static inline void notify_cmos_timer(void) { } | |
539 | #endif | |
540 | ||
80f22571 IM |
541 | |
542 | /* | |
543 | * Propagate a new txc->status value into the NTP state: | |
544 | */ | |
545 | static inline void process_adj_status(struct timex *txc, struct timespec *ts) | |
546 | { | |
80f22571 IM |
547 | if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) { |
548 | time_state = TIME_OK; | |
549 | time_status = STA_UNSYNC; | |
025b40ab AG |
550 | /* restart PPS frequency calibration */ |
551 | pps_reset_freq_interval(); | |
80f22571 | 552 | } |
80f22571 IM |
553 | |
554 | /* | |
555 | * If we turn on PLL adjustments then reset the | |
556 | * reference time to current time. | |
557 | */ | |
558 | if (!(time_status & STA_PLL) && (txc->status & STA_PLL)) | |
7e1b5847 | 559 | time_reftime = get_seconds(); |
80f22571 | 560 | |
a2a5ac86 JS |
561 | /* only set allowed bits */ |
562 | time_status &= STA_RONLY; | |
80f22571 | 563 | time_status |= txc->status & ~STA_RONLY; |
80f22571 | 564 | } |
cd5398be | 565 | |
80f22571 | 566 | /* |
cd5398be | 567 | * Called with ntp_lock held, so we can access and modify |
80f22571 IM |
568 | * all the global NTP state: |
569 | */ | |
570 | static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts) | |
571 | { | |
572 | if (txc->modes & ADJ_STATUS) | |
573 | process_adj_status(txc, ts); | |
574 | ||
575 | if (txc->modes & ADJ_NANO) | |
576 | time_status |= STA_NANO; | |
e9629165 | 577 | |
80f22571 IM |
578 | if (txc->modes & ADJ_MICRO) |
579 | time_status &= ~STA_NANO; | |
580 | ||
581 | if (txc->modes & ADJ_FREQUENCY) { | |
2b9d1496 | 582 | time_freq = txc->freq * PPM_SCALE; |
80f22571 IM |
583 | time_freq = min(time_freq, MAXFREQ_SCALED); |
584 | time_freq = max(time_freq, -MAXFREQ_SCALED); | |
025b40ab AG |
585 | /* update pps_freq */ |
586 | pps_set_freq(time_freq); | |
80f22571 IM |
587 | } |
588 | ||
589 | if (txc->modes & ADJ_MAXERROR) | |
590 | time_maxerror = txc->maxerror; | |
e9629165 | 591 | |
80f22571 IM |
592 | if (txc->modes & ADJ_ESTERROR) |
593 | time_esterror = txc->esterror; | |
594 | ||
595 | if (txc->modes & ADJ_TIMECONST) { | |
596 | time_constant = txc->constant; | |
597 | if (!(time_status & STA_NANO)) | |
598 | time_constant += 4; | |
599 | time_constant = min(time_constant, (long)MAXTC); | |
600 | time_constant = max(time_constant, 0l); | |
601 | } | |
602 | ||
603 | if (txc->modes & ADJ_TAI && txc->constant > 0) | |
604 | time_tai = txc->constant; | |
605 | ||
606 | if (txc->modes & ADJ_OFFSET) | |
607 | ntp_update_offset(txc->offset); | |
e9629165 | 608 | |
80f22571 IM |
609 | if (txc->modes & ADJ_TICK) |
610 | tick_usec = txc->tick; | |
611 | ||
612 | if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET)) | |
613 | ntp_update_frequency(); | |
614 | } | |
615 | ||
53bbfa9e IM |
616 | /* |
617 | * adjtimex mainly allows reading (and writing, if superuser) of | |
4c7ee8de | 618 | * kernel time-keeping variables. used by xntpd. |
619 | */ | |
620 | int do_adjtimex(struct timex *txc) | |
621 | { | |
eea83d89 | 622 | struct timespec ts; |
4c7ee8de | 623 | int result; |
624 | ||
916c7a85 RZ |
625 | /* Validate the data before disabling interrupts */ |
626 | if (txc->modes & ADJ_ADJTIME) { | |
eea83d89 | 627 | /* singleshot must not be used with any other mode bits */ |
916c7a85 | 628 | if (!(txc->modes & ADJ_OFFSET_SINGLESHOT)) |
4c7ee8de | 629 | return -EINVAL; |
916c7a85 RZ |
630 | if (!(txc->modes & ADJ_OFFSET_READONLY) && |
631 | !capable(CAP_SYS_TIME)) | |
632 | return -EPERM; | |
633 | } else { | |
634 | /* In order to modify anything, you gotta be super-user! */ | |
635 | if (txc->modes && !capable(CAP_SYS_TIME)) | |
636 | return -EPERM; | |
637 | ||
53bbfa9e IM |
638 | /* |
639 | * if the quartz is off by more than 10% then | |
640 | * something is VERY wrong! | |
641 | */ | |
916c7a85 RZ |
642 | if (txc->modes & ADJ_TICK && |
643 | (txc->tick < 900000/USER_HZ || | |
644 | txc->tick > 1100000/USER_HZ)) | |
e9629165 | 645 | return -EINVAL; |
52bfb360 | 646 | } |
4c7ee8de | 647 | |
094aa188 RC |
648 | if (txc->modes & ADJ_SETOFFSET) { |
649 | struct timespec delta; | |
094aa188 RC |
650 | delta.tv_sec = txc->time.tv_sec; |
651 | delta.tv_nsec = txc->time.tv_usec; | |
4352d9d4 RC |
652 | if (!capable(CAP_SYS_TIME)) |
653 | return -EPERM; | |
094aa188 RC |
654 | if (!(txc->modes & ADJ_NANO)) |
655 | delta.tv_nsec *= 1000; | |
db1c1cce RC |
656 | result = timekeeping_inject_offset(&delta); |
657 | if (result) | |
658 | return result; | |
094aa188 RC |
659 | } |
660 | ||
7dffa3c6 RZ |
661 | getnstimeofday(&ts); |
662 | ||
bd331268 | 663 | spin_lock_irq(&ntp_lock); |
4c7ee8de | 664 | |
916c7a85 RZ |
665 | if (txc->modes & ADJ_ADJTIME) { |
666 | long save_adjust = time_adjust; | |
667 | ||
668 | if (!(txc->modes & ADJ_OFFSET_READONLY)) { | |
669 | /* adjtime() is independent from ntp_adjtime() */ | |
670 | time_adjust = txc->offset; | |
671 | ntp_update_frequency(); | |
672 | } | |
673 | txc->offset = save_adjust; | |
e9629165 | 674 | } else { |
ee9851b2 | 675 | |
e9629165 IM |
676 | /* If there are input parameters, then process them: */ |
677 | if (txc->modes) | |
678 | process_adjtimex_modes(txc, &ts); | |
eea83d89 | 679 | |
e9629165 | 680 | txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ, |
916c7a85 | 681 | NTP_SCALE_SHIFT); |
e9629165 IM |
682 | if (!(time_status & STA_NANO)) |
683 | txc->offset /= NSEC_PER_USEC; | |
684 | } | |
916c7a85 | 685 | |
eea83d89 | 686 | result = time_state; /* mostly `TIME_OK' */ |
025b40ab AG |
687 | /* check for errors */ |
688 | if (is_error_status(time_status)) | |
4c7ee8de | 689 | result = TIME_ERROR; |
690 | ||
d40e944c | 691 | txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) * |
2b9d1496 | 692 | PPM_SCALE_INV, NTP_SCALE_SHIFT); |
4c7ee8de | 693 | txc->maxerror = time_maxerror; |
694 | txc->esterror = time_esterror; | |
695 | txc->status = time_status; | |
696 | txc->constant = time_constant; | |
70bc42f9 | 697 | txc->precision = 1; |
074b3b87 | 698 | txc->tolerance = MAXFREQ_SCALED / PPM_SCALE; |
4c7ee8de | 699 | txc->tick = tick_usec; |
153b5d05 | 700 | txc->tai = time_tai; |
4c7ee8de | 701 | |
025b40ab AG |
702 | /* fill PPS status fields */ |
703 | pps_fill_timex(txc); | |
e9629165 | 704 | |
bd331268 | 705 | spin_unlock_irq(&ntp_lock); |
ee9851b2 | 706 | |
eea83d89 RZ |
707 | txc->time.tv_sec = ts.tv_sec; |
708 | txc->time.tv_usec = ts.tv_nsec; | |
709 | if (!(time_status & STA_NANO)) | |
710 | txc->time.tv_usec /= NSEC_PER_USEC; | |
ee9851b2 | 711 | |
82644459 | 712 | notify_cmos_timer(); |
ee9851b2 RZ |
713 | |
714 | return result; | |
4c7ee8de | 715 | } |
10a398d0 | 716 | |
025b40ab AG |
717 | #ifdef CONFIG_NTP_PPS |
718 | ||
719 | /* actually struct pps_normtime is good old struct timespec, but it is | |
720 | * semantically different (and it is the reason why it was invented): | |
721 | * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] | |
722 | * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */ | |
723 | struct pps_normtime { | |
724 | __kernel_time_t sec; /* seconds */ | |
725 | long nsec; /* nanoseconds */ | |
726 | }; | |
727 | ||
728 | /* normalize the timestamp so that nsec is in the | |
729 | ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */ | |
730 | static inline struct pps_normtime pps_normalize_ts(struct timespec ts) | |
731 | { | |
732 | struct pps_normtime norm = { | |
733 | .sec = ts.tv_sec, | |
734 | .nsec = ts.tv_nsec | |
735 | }; | |
736 | ||
737 | if (norm.nsec > (NSEC_PER_SEC >> 1)) { | |
738 | norm.nsec -= NSEC_PER_SEC; | |
739 | norm.sec++; | |
740 | } | |
741 | ||
742 | return norm; | |
743 | } | |
744 | ||
745 | /* get current phase correction and jitter */ | |
746 | static inline long pps_phase_filter_get(long *jitter) | |
747 | { | |
748 | *jitter = pps_tf[0] - pps_tf[1]; | |
749 | if (*jitter < 0) | |
750 | *jitter = -*jitter; | |
751 | ||
752 | /* TODO: test various filters */ | |
753 | return pps_tf[0]; | |
754 | } | |
755 | ||
756 | /* add the sample to the phase filter */ | |
757 | static inline void pps_phase_filter_add(long err) | |
758 | { | |
759 | pps_tf[2] = pps_tf[1]; | |
760 | pps_tf[1] = pps_tf[0]; | |
761 | pps_tf[0] = err; | |
762 | } | |
763 | ||
764 | /* decrease frequency calibration interval length. | |
765 | * It is halved after four consecutive unstable intervals. | |
766 | */ | |
767 | static inline void pps_dec_freq_interval(void) | |
768 | { | |
769 | if (--pps_intcnt <= -PPS_INTCOUNT) { | |
770 | pps_intcnt = -PPS_INTCOUNT; | |
771 | if (pps_shift > PPS_INTMIN) { | |
772 | pps_shift--; | |
773 | pps_intcnt = 0; | |
774 | } | |
775 | } | |
776 | } | |
777 | ||
778 | /* increase frequency calibration interval length. | |
779 | * It is doubled after four consecutive stable intervals. | |
780 | */ | |
781 | static inline void pps_inc_freq_interval(void) | |
782 | { | |
783 | if (++pps_intcnt >= PPS_INTCOUNT) { | |
784 | pps_intcnt = PPS_INTCOUNT; | |
785 | if (pps_shift < PPS_INTMAX) { | |
786 | pps_shift++; | |
787 | pps_intcnt = 0; | |
788 | } | |
789 | } | |
790 | } | |
791 | ||
792 | /* update clock frequency based on MONOTONIC_RAW clock PPS signal | |
793 | * timestamps | |
794 | * | |
795 | * At the end of the calibration interval the difference between the | |
796 | * first and last MONOTONIC_RAW clock timestamps divided by the length | |
797 | * of the interval becomes the frequency update. If the interval was | |
798 | * too long, the data are discarded. | |
799 | * Returns the difference between old and new frequency values. | |
800 | */ | |
801 | static long hardpps_update_freq(struct pps_normtime freq_norm) | |
802 | { | |
803 | long delta, delta_mod; | |
804 | s64 ftemp; | |
805 | ||
806 | /* check if the frequency interval was too long */ | |
807 | if (freq_norm.sec > (2 << pps_shift)) { | |
808 | time_status |= STA_PPSERROR; | |
809 | pps_errcnt++; | |
810 | pps_dec_freq_interval(); | |
811 | pr_err("hardpps: PPSERROR: interval too long - %ld s\n", | |
812 | freq_norm.sec); | |
813 | return 0; | |
814 | } | |
815 | ||
816 | /* here the raw frequency offset and wander (stability) is | |
817 | * calculated. If the wander is less than the wander threshold | |
818 | * the interval is increased; otherwise it is decreased. | |
819 | */ | |
820 | ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT, | |
821 | freq_norm.sec); | |
822 | delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT); | |
823 | pps_freq = ftemp; | |
824 | if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) { | |
825 | pr_warning("hardpps: PPSWANDER: change=%ld\n", delta); | |
826 | time_status |= STA_PPSWANDER; | |
827 | pps_stbcnt++; | |
828 | pps_dec_freq_interval(); | |
829 | } else { /* good sample */ | |
830 | pps_inc_freq_interval(); | |
831 | } | |
832 | ||
833 | /* the stability metric is calculated as the average of recent | |
834 | * frequency changes, but is used only for performance | |
835 | * monitoring | |
836 | */ | |
837 | delta_mod = delta; | |
838 | if (delta_mod < 0) | |
839 | delta_mod = -delta_mod; | |
840 | pps_stabil += (div_s64(((s64)delta_mod) << | |
841 | (NTP_SCALE_SHIFT - SHIFT_USEC), | |
842 | NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN; | |
843 | ||
844 | /* if enabled, the system clock frequency is updated */ | |
845 | if ((time_status & STA_PPSFREQ) != 0 && | |
846 | (time_status & STA_FREQHOLD) == 0) { | |
847 | time_freq = pps_freq; | |
848 | ntp_update_frequency(); | |
849 | } | |
850 | ||
851 | return delta; | |
852 | } | |
853 | ||
854 | /* correct REALTIME clock phase error against PPS signal */ | |
855 | static void hardpps_update_phase(long error) | |
856 | { | |
857 | long correction = -error; | |
858 | long jitter; | |
859 | ||
860 | /* add the sample to the median filter */ | |
861 | pps_phase_filter_add(correction); | |
862 | correction = pps_phase_filter_get(&jitter); | |
863 | ||
864 | /* Nominal jitter is due to PPS signal noise. If it exceeds the | |
865 | * threshold, the sample is discarded; otherwise, if so enabled, | |
866 | * the time offset is updated. | |
867 | */ | |
868 | if (jitter > (pps_jitter << PPS_POPCORN)) { | |
869 | pr_warning("hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", | |
870 | jitter, (pps_jitter << PPS_POPCORN)); | |
871 | time_status |= STA_PPSJITTER; | |
872 | pps_jitcnt++; | |
873 | } else if (time_status & STA_PPSTIME) { | |
874 | /* correct the time using the phase offset */ | |
875 | time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT, | |
876 | NTP_INTERVAL_FREQ); | |
877 | /* cancel running adjtime() */ | |
878 | time_adjust = 0; | |
879 | } | |
880 | /* update jitter */ | |
881 | pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN; | |
882 | } | |
883 | ||
884 | /* | |
885 | * hardpps() - discipline CPU clock oscillator to external PPS signal | |
886 | * | |
887 | * This routine is called at each PPS signal arrival in order to | |
888 | * discipline the CPU clock oscillator to the PPS signal. It takes two | |
889 | * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former | |
890 | * is used to correct clock phase error and the latter is used to | |
891 | * correct the frequency. | |
892 | * | |
893 | * This code is based on David Mills's reference nanokernel | |
894 | * implementation. It was mostly rewritten but keeps the same idea. | |
895 | */ | |
896 | void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) | |
897 | { | |
898 | struct pps_normtime pts_norm, freq_norm; | |
899 | unsigned long flags; | |
900 | ||
901 | pts_norm = pps_normalize_ts(*phase_ts); | |
902 | ||
bd331268 | 903 | spin_lock_irqsave(&ntp_lock, flags); |
025b40ab AG |
904 | |
905 | /* clear the error bits, they will be set again if needed */ | |
906 | time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); | |
907 | ||
908 | /* indicate signal presence */ | |
909 | time_status |= STA_PPSSIGNAL; | |
910 | pps_valid = PPS_VALID; | |
911 | ||
912 | /* when called for the first time, | |
913 | * just start the frequency interval */ | |
914 | if (unlikely(pps_fbase.tv_sec == 0)) { | |
915 | pps_fbase = *raw_ts; | |
bd331268 | 916 | spin_unlock_irqrestore(&ntp_lock, flags); |
025b40ab AG |
917 | return; |
918 | } | |
919 | ||
920 | /* ok, now we have a base for frequency calculation */ | |
921 | freq_norm = pps_normalize_ts(timespec_sub(*raw_ts, pps_fbase)); | |
922 | ||
923 | /* check that the signal is in the range | |
924 | * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */ | |
925 | if ((freq_norm.sec == 0) || | |
926 | (freq_norm.nsec > MAXFREQ * freq_norm.sec) || | |
927 | (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) { | |
928 | time_status |= STA_PPSJITTER; | |
929 | /* restart the frequency calibration interval */ | |
930 | pps_fbase = *raw_ts; | |
bd331268 | 931 | spin_unlock_irqrestore(&ntp_lock, flags); |
025b40ab AG |
932 | pr_err("hardpps: PPSJITTER: bad pulse\n"); |
933 | return; | |
934 | } | |
935 | ||
936 | /* signal is ok */ | |
937 | ||
938 | /* check if the current frequency interval is finished */ | |
939 | if (freq_norm.sec >= (1 << pps_shift)) { | |
940 | pps_calcnt++; | |
941 | /* restart the frequency calibration interval */ | |
942 | pps_fbase = *raw_ts; | |
943 | hardpps_update_freq(freq_norm); | |
944 | } | |
945 | ||
946 | hardpps_update_phase(pts_norm.nsec); | |
947 | ||
bd331268 | 948 | spin_unlock_irqrestore(&ntp_lock, flags); |
025b40ab AG |
949 | } |
950 | EXPORT_SYMBOL(hardpps); | |
951 | ||
952 | #endif /* CONFIG_NTP_PPS */ | |
953 | ||
10a398d0 RZ |
954 | static int __init ntp_tick_adj_setup(char *str) |
955 | { | |
956 | ntp_tick_adj = simple_strtol(str, NULL, 0); | |
069569e0 IM |
957 | ntp_tick_adj <<= NTP_SCALE_SHIFT; |
958 | ||
10a398d0 RZ |
959 | return 1; |
960 | } | |
961 | ||
962 | __setup("ntp_tick_adj=", ntp_tick_adj_setup); | |
7dffa3c6 RZ |
963 | |
964 | void __init ntp_init(void) | |
965 | { | |
966 | ntp_clear(); | |
7dffa3c6 | 967 | } |