]>
Commit | Line | Data |
---|---|---|
8524070b JS |
1 | /* |
2 | * linux/kernel/time/timekeeping.c | |
3 | * | |
4 | * Kernel timekeeping code and accessor functions | |
5 | * | |
6 | * This code was moved from linux/kernel/timer.c. | |
7 | * Please see that file for copyright and history logs. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/percpu.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/sysdev.h> | |
17 | #include <linux/clocksource.h> | |
18 | #include <linux/jiffies.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/tick.h> | |
21 | ||
155ec602 MS |
22 | /* Structure holding internal timekeeping values. */ |
23 | struct timekeeper { | |
24 | /* Current clocksource used for timekeeping. */ | |
25 | struct clocksource *clock; | |
23ce7211 MS |
26 | /* The shift value of the current clocksource. */ |
27 | int shift; | |
155ec602 MS |
28 | |
29 | /* Number of clock cycles in one NTP interval. */ | |
30 | cycle_t cycle_interval; | |
31 | /* Number of clock shifted nano seconds in one NTP interval. */ | |
32 | u64 xtime_interval; | |
33 | /* Raw nano seconds accumulated per NTP interval. */ | |
34 | u32 raw_interval; | |
35 | ||
36 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ | |
37 | u64 xtime_nsec; | |
38 | /* Difference between accumulated time and NTP time in ntp | |
39 | * shifted nano seconds. */ | |
40 | s64 ntp_error; | |
23ce7211 MS |
41 | /* Shift conversion between clock shifted nano seconds and |
42 | * ntp shifted nano seconds. */ | |
43 | int ntp_error_shift; | |
0a544198 MS |
44 | /* NTP adjusted clock multiplier */ |
45 | u32 mult; | |
155ec602 MS |
46 | }; |
47 | ||
48 | struct timekeeper timekeeper; | |
49 | ||
50 | /** | |
51 | * timekeeper_setup_internals - Set up internals to use clocksource clock. | |
52 | * | |
53 | * @clock: Pointer to clocksource. | |
54 | * | |
55 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment | |
56 | * pair and interval request. | |
57 | * | |
58 | * Unless you're the timekeeping code, you should not be using this! | |
59 | */ | |
60 | static void timekeeper_setup_internals(struct clocksource *clock) | |
61 | { | |
62 | cycle_t interval; | |
63 | u64 tmp; | |
64 | ||
65 | timekeeper.clock = clock; | |
66 | clock->cycle_last = clock->read(clock); | |
67 | ||
68 | /* Do the ns -> cycle conversion first, using original mult */ | |
69 | tmp = NTP_INTERVAL_LENGTH; | |
70 | tmp <<= clock->shift; | |
0a544198 MS |
71 | tmp += clock->mult/2; |
72 | do_div(tmp, clock->mult); | |
155ec602 MS |
73 | if (tmp == 0) |
74 | tmp = 1; | |
75 | ||
76 | interval = (cycle_t) tmp; | |
77 | timekeeper.cycle_interval = interval; | |
78 | ||
79 | /* Go back from cycles -> shifted ns */ | |
80 | timekeeper.xtime_interval = (u64) interval * clock->mult; | |
81 | timekeeper.raw_interval = | |
0a544198 | 82 | ((u64) interval * clock->mult) >> clock->shift; |
155ec602 MS |
83 | |
84 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 85 | timekeeper.shift = clock->shift; |
155ec602 MS |
86 | |
87 | timekeeper.ntp_error = 0; | |
23ce7211 | 88 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
0a544198 MS |
89 | |
90 | /* | |
91 | * The timekeeper keeps its own mult values for the currently | |
92 | * active clocksource. These value will be adjusted via NTP | |
93 | * to counteract clock drifting. | |
94 | */ | |
95 | timekeeper.mult = clock->mult; | |
155ec602 | 96 | } |
8524070b JS |
97 | |
98 | /* | |
99 | * This read-write spinlock protects us from races in SMP while | |
dce48a84 | 100 | * playing with xtime. |
8524070b | 101 | */ |
ba2a631b | 102 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
8524070b JS |
103 | |
104 | ||
105 | /* | |
106 | * The current time | |
107 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected | |
108 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged | |
109 | * at zero at system boot time, so wall_to_monotonic will be negative, | |
110 | * however, we will ALWAYS keep the tv_nsec part positive so we can use | |
111 | * the usual normalization. | |
7c3f1a57 TJ |
112 | * |
113 | * wall_to_monotonic is moved after resume from suspend for the monotonic | |
114 | * time not to jump. We need to add total_sleep_time to wall_to_monotonic | |
115 | * to get the real boot based time offset. | |
116 | * | |
117 | * - wall_to_monotonic is no longer the boot time, getboottime must be | |
118 | * used instead. | |
8524070b JS |
119 | */ |
120 | struct timespec xtime __attribute__ ((aligned (16))); | |
121 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); | |
7c3f1a57 | 122 | static unsigned long total_sleep_time; /* seconds */ |
8524070b | 123 | |
155ec602 MS |
124 | /* |
125 | * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. | |
126 | */ | |
127 | struct timespec raw_time; | |
128 | ||
1c5745aa TG |
129 | /* flag for if timekeeping is suspended */ |
130 | int __read_mostly timekeeping_suspended; | |
131 | ||
17c38b74 | 132 | static struct timespec xtime_cache __attribute__ ((aligned (16))); |
1001d0a9 | 133 | void update_xtime_cache(u64 nsec) |
17c38b74 JS |
134 | { |
135 | xtime_cache = xtime; | |
136 | timespec_add_ns(&xtime_cache, nsec); | |
137 | } | |
17c38b74 | 138 | |
31089c13 JS |
139 | /* must hold xtime_lock */ |
140 | void timekeeping_leap_insert(int leapsecond) | |
141 | { | |
142 | xtime.tv_sec += leapsecond; | |
143 | wall_to_monotonic.tv_sec -= leapsecond; | |
155ec602 | 144 | update_vsyscall(&xtime, timekeeper.clock); |
31089c13 | 145 | } |
8524070b JS |
146 | |
147 | #ifdef CONFIG_GENERIC_TIME | |
148 | /** | |
155ec602 | 149 | * timekeeping_forward_now - update clock to the current time |
8524070b | 150 | * |
9a055117 RZ |
151 | * Forward the current clock to update its state since the last call to |
152 | * update_wall_time(). This is useful before significant clock changes, | |
153 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 154 | */ |
155ec602 | 155 | static void timekeeping_forward_now(void) |
8524070b JS |
156 | { |
157 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 158 | struct clocksource *clock; |
9a055117 | 159 | s64 nsec; |
8524070b | 160 | |
155ec602 | 161 | clock = timekeeper.clock; |
a0f7d48b | 162 | cycle_now = clock->read(clock); |
8524070b | 163 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 164 | clock->cycle_last = cycle_now; |
8524070b | 165 | |
0a544198 MS |
166 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
167 | timekeeper.shift); | |
7d27558c JS |
168 | |
169 | /* If arch requires, add in gettimeoffset() */ | |
170 | nsec += arch_gettimeoffset(); | |
171 | ||
9a055117 | 172 | timespec_add_ns(&xtime, nsec); |
2d42244a | 173 | |
0a544198 | 174 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
155ec602 | 175 | timespec_add_ns(&raw_time, nsec); |
8524070b JS |
176 | } |
177 | ||
178 | /** | |
efd9ac86 | 179 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
180 | * @ts: pointer to the timespec to be set |
181 | * | |
efd9ac86 | 182 | * Returns the time of day in a timespec. |
8524070b | 183 | */ |
efd9ac86 | 184 | void getnstimeofday(struct timespec *ts) |
8524070b | 185 | { |
9a055117 | 186 | cycle_t cycle_now, cycle_delta; |
155ec602 | 187 | struct clocksource *clock; |
8524070b JS |
188 | unsigned long seq; |
189 | s64 nsecs; | |
190 | ||
1c5745aa TG |
191 | WARN_ON(timekeeping_suspended); |
192 | ||
8524070b JS |
193 | do { |
194 | seq = read_seqbegin(&xtime_lock); | |
195 | ||
196 | *ts = xtime; | |
9a055117 RZ |
197 | |
198 | /* read clocksource: */ | |
155ec602 | 199 | clock = timekeeper.clock; |
a0f7d48b | 200 | cycle_now = clock->read(clock); |
9a055117 RZ |
201 | |
202 | /* calculate the delta since the last update_wall_time: */ | |
203 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
204 | ||
205 | /* convert to nanoseconds: */ | |
0a544198 MS |
206 | nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
207 | timekeeper.shift); | |
8524070b | 208 | |
7d27558c JS |
209 | /* If arch requires, add in gettimeoffset() */ |
210 | nsecs += arch_gettimeoffset(); | |
211 | ||
8524070b JS |
212 | } while (read_seqretry(&xtime_lock, seq)); |
213 | ||
214 | timespec_add_ns(ts, nsecs); | |
215 | } | |
216 | ||
8524070b JS |
217 | EXPORT_SYMBOL(getnstimeofday); |
218 | ||
951ed4d3 MS |
219 | ktime_t ktime_get(void) |
220 | { | |
221 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 222 | struct clocksource *clock; |
951ed4d3 MS |
223 | unsigned int seq; |
224 | s64 secs, nsecs; | |
225 | ||
226 | WARN_ON(timekeeping_suspended); | |
227 | ||
228 | do { | |
229 | seq = read_seqbegin(&xtime_lock); | |
230 | secs = xtime.tv_sec + wall_to_monotonic.tv_sec; | |
231 | nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; | |
232 | ||
233 | /* read clocksource: */ | |
155ec602 | 234 | clock = timekeeper.clock; |
a0f7d48b | 235 | cycle_now = clock->read(clock); |
951ed4d3 MS |
236 | |
237 | /* calculate the delta since the last update_wall_time: */ | |
238 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
239 | ||
240 | /* convert to nanoseconds: */ | |
0a544198 MS |
241 | nsecs += clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
242 | timekeeper.shift); | |
951ed4d3 MS |
243 | |
244 | } while (read_seqretry(&xtime_lock, seq)); | |
245 | /* | |
246 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
247 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
248 | */ | |
249 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
250 | } | |
251 | EXPORT_SYMBOL_GPL(ktime_get); | |
252 | ||
253 | /** | |
254 | * ktime_get_ts - get the monotonic clock in timespec format | |
255 | * @ts: pointer to timespec variable | |
256 | * | |
257 | * The function calculates the monotonic clock from the realtime | |
258 | * clock and the wall_to_monotonic offset and stores the result | |
259 | * in normalized timespec format in the variable pointed to by @ts. | |
260 | */ | |
261 | void ktime_get_ts(struct timespec *ts) | |
262 | { | |
263 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 264 | struct clocksource *clock; |
951ed4d3 MS |
265 | struct timespec tomono; |
266 | unsigned int seq; | |
267 | s64 nsecs; | |
268 | ||
269 | WARN_ON(timekeeping_suspended); | |
270 | ||
271 | do { | |
272 | seq = read_seqbegin(&xtime_lock); | |
273 | *ts = xtime; | |
274 | tomono = wall_to_monotonic; | |
275 | ||
276 | /* read clocksource: */ | |
155ec602 | 277 | clock = timekeeper.clock; |
a0f7d48b | 278 | cycle_now = clock->read(clock); |
951ed4d3 MS |
279 | |
280 | /* calculate the delta since the last update_wall_time: */ | |
281 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
282 | ||
283 | /* convert to nanoseconds: */ | |
0a544198 MS |
284 | nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
285 | timekeeper.shift); | |
951ed4d3 MS |
286 | |
287 | } while (read_seqretry(&xtime_lock, seq)); | |
288 | ||
289 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
290 | ts->tv_nsec + tomono.tv_nsec + nsecs); | |
291 | } | |
292 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
293 | ||
8524070b JS |
294 | /** |
295 | * do_gettimeofday - Returns the time of day in a timeval | |
296 | * @tv: pointer to the timeval to be set | |
297 | * | |
efd9ac86 | 298 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
299 | */ |
300 | void do_gettimeofday(struct timeval *tv) | |
301 | { | |
302 | struct timespec now; | |
303 | ||
efd9ac86 | 304 | getnstimeofday(&now); |
8524070b JS |
305 | tv->tv_sec = now.tv_sec; |
306 | tv->tv_usec = now.tv_nsec/1000; | |
307 | } | |
308 | ||
309 | EXPORT_SYMBOL(do_gettimeofday); | |
310 | /** | |
311 | * do_settimeofday - Sets the time of day | |
312 | * @tv: pointer to the timespec variable containing the new time | |
313 | * | |
314 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
315 | */ | |
316 | int do_settimeofday(struct timespec *tv) | |
317 | { | |
9a055117 | 318 | struct timespec ts_delta; |
8524070b | 319 | unsigned long flags; |
8524070b JS |
320 | |
321 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
322 | return -EINVAL; | |
323 | ||
324 | write_seqlock_irqsave(&xtime_lock, flags); | |
325 | ||
155ec602 | 326 | timekeeping_forward_now(); |
9a055117 RZ |
327 | |
328 | ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec; | |
329 | ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec; | |
330 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta); | |
8524070b | 331 | |
9a055117 | 332 | xtime = *tv; |
8524070b | 333 | |
1001d0a9 | 334 | update_xtime_cache(0); |
8524070b | 335 | |
155ec602 | 336 | timekeeper.ntp_error = 0; |
8524070b JS |
337 | ntp_clear(); |
338 | ||
155ec602 | 339 | update_vsyscall(&xtime, timekeeper.clock); |
8524070b JS |
340 | |
341 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
342 | ||
343 | /* signal hrtimers about time change */ | |
344 | clock_was_set(); | |
345 | ||
346 | return 0; | |
347 | } | |
348 | ||
349 | EXPORT_SYMBOL(do_settimeofday); | |
350 | ||
351 | /** | |
352 | * change_clocksource - Swaps clocksources if a new one is available | |
353 | * | |
354 | * Accumulates current time interval and initializes new clocksource | |
355 | */ | |
356 | static void change_clocksource(void) | |
357 | { | |
4614e6ad | 358 | struct clocksource *new, *old; |
8524070b JS |
359 | |
360 | new = clocksource_get_next(); | |
361 | ||
155ec602 | 362 | if (!new || timekeeper.clock == new) |
8524070b JS |
363 | return; |
364 | ||
155ec602 | 365 | timekeeping_forward_now(); |
8524070b | 366 | |
a0f7d48b | 367 | if (new->enable && !new->enable(new)) |
4614e6ad | 368 | return; |
2d42244a | 369 | |
155ec602 MS |
370 | old = timekeeper.clock; |
371 | timekeeper_setup_internals(new); | |
372 | ||
a0f7d48b MS |
373 | if (old->disable) |
374 | old->disable(old); | |
4614e6ad | 375 | |
8524070b | 376 | tick_clock_notify(); |
8524070b | 377 | } |
a40f262c | 378 | #else /* GENERIC_TIME */ |
155ec602 | 379 | static inline void timekeeping_forward_now(void) { } |
8524070b | 380 | static inline void change_clocksource(void) { } |
a40f262c TG |
381 | |
382 | /** | |
383 | * ktime_get - get the monotonic time in ktime_t format | |
384 | * | |
385 | * returns the time in ktime_t format | |
386 | */ | |
387 | ktime_t ktime_get(void) | |
388 | { | |
389 | struct timespec now; | |
390 | ||
391 | ktime_get_ts(&now); | |
392 | ||
393 | return timespec_to_ktime(now); | |
394 | } | |
395 | EXPORT_SYMBOL_GPL(ktime_get); | |
396 | ||
397 | /** | |
398 | * ktime_get_ts - get the monotonic clock in timespec format | |
399 | * @ts: pointer to timespec variable | |
400 | * | |
401 | * The function calculates the monotonic clock from the realtime | |
402 | * clock and the wall_to_monotonic offset and stores the result | |
403 | * in normalized timespec format in the variable pointed to by @ts. | |
404 | */ | |
405 | void ktime_get_ts(struct timespec *ts) | |
406 | { | |
407 | struct timespec tomono; | |
408 | unsigned long seq; | |
409 | ||
410 | do { | |
411 | seq = read_seqbegin(&xtime_lock); | |
412 | getnstimeofday(ts); | |
413 | tomono = wall_to_monotonic; | |
414 | ||
415 | } while (read_seqretry(&xtime_lock, seq)); | |
416 | ||
417 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
418 | ts->tv_nsec + tomono.tv_nsec); | |
419 | } | |
420 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
421 | #endif /* !GENERIC_TIME */ | |
422 | ||
423 | /** | |
424 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
425 | * | |
426 | * returns the time in ktime_t format | |
427 | */ | |
428 | ktime_t ktime_get_real(void) | |
429 | { | |
430 | struct timespec now; | |
431 | ||
432 | getnstimeofday(&now); | |
433 | ||
434 | return timespec_to_ktime(now); | |
435 | } | |
436 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 437 | |
2d42244a JS |
438 | /** |
439 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
440 | * @ts: pointer to the timespec to be set | |
441 | * | |
442 | * Returns the raw monotonic time (completely un-modified by ntp) | |
443 | */ | |
444 | void getrawmonotonic(struct timespec *ts) | |
445 | { | |
446 | unsigned long seq; | |
447 | s64 nsecs; | |
448 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 449 | struct clocksource *clock; |
2d42244a JS |
450 | |
451 | do { | |
452 | seq = read_seqbegin(&xtime_lock); | |
453 | ||
454 | /* read clocksource: */ | |
155ec602 | 455 | clock = timekeeper.clock; |
a0f7d48b | 456 | cycle_now = clock->read(clock); |
2d42244a JS |
457 | |
458 | /* calculate the delta since the last update_wall_time: */ | |
459 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
460 | ||
461 | /* convert to nanoseconds: */ | |
0a544198 | 462 | nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, |
155ec602 | 463 | clock->shift); |
2d42244a | 464 | |
155ec602 | 465 | *ts = raw_time; |
2d42244a JS |
466 | |
467 | } while (read_seqretry(&xtime_lock, seq)); | |
468 | ||
469 | timespec_add_ns(ts, nsecs); | |
470 | } | |
471 | EXPORT_SYMBOL(getrawmonotonic); | |
472 | ||
473 | ||
8524070b | 474 | /** |
cf4fc6cb | 475 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 476 | */ |
cf4fc6cb | 477 | int timekeeping_valid_for_hres(void) |
8524070b JS |
478 | { |
479 | unsigned long seq; | |
480 | int ret; | |
481 | ||
482 | do { | |
483 | seq = read_seqbegin(&xtime_lock); | |
484 | ||
155ec602 | 485 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b JS |
486 | |
487 | } while (read_seqretry(&xtime_lock, seq)); | |
488 | ||
489 | return ret; | |
490 | } | |
491 | ||
492 | /** | |
493 | * read_persistent_clock - Return time in seconds from the persistent clock. | |
494 | * | |
495 | * Weak dummy function for arches that do not yet support it. | |
496 | * Returns seconds from epoch using the battery backed persistent clock. | |
497 | * Returns zero if unsupported. | |
498 | * | |
499 | * XXX - Do be sure to remove it once all arches implement it. | |
500 | */ | |
501 | unsigned long __attribute__((weak)) read_persistent_clock(void) | |
502 | { | |
503 | return 0; | |
504 | } | |
505 | ||
506 | /* | |
507 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
508 | */ | |
509 | void __init timekeeping_init(void) | |
510 | { | |
155ec602 | 511 | struct clocksource *clock; |
8524070b JS |
512 | unsigned long flags; |
513 | unsigned long sec = read_persistent_clock(); | |
514 | ||
515 | write_seqlock_irqsave(&xtime_lock, flags); | |
516 | ||
7dffa3c6 | 517 | ntp_init(); |
8524070b | 518 | |
f1b82746 | 519 | clock = clocksource_default_clock(); |
a0f7d48b MS |
520 | if (clock->enable) |
521 | clock->enable(clock); | |
155ec602 | 522 | timekeeper_setup_internals(clock); |
8524070b JS |
523 | |
524 | xtime.tv_sec = sec; | |
525 | xtime.tv_nsec = 0; | |
155ec602 MS |
526 | raw_time.tv_sec = 0; |
527 | raw_time.tv_nsec = 0; | |
8524070b JS |
528 | set_normalized_timespec(&wall_to_monotonic, |
529 | -xtime.tv_sec, -xtime.tv_nsec); | |
1001d0a9 | 530 | update_xtime_cache(0); |
7c3f1a57 | 531 | total_sleep_time = 0; |
8524070b JS |
532 | write_sequnlock_irqrestore(&xtime_lock, flags); |
533 | } | |
534 | ||
8524070b JS |
535 | /* time in seconds when suspend began */ |
536 | static unsigned long timekeeping_suspend_time; | |
537 | ||
538 | /** | |
539 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
540 | * @dev: unused | |
541 | * | |
542 | * This is for the generic clocksource timekeeping. | |
543 | * xtime/wall_to_monotonic/jiffies/etc are | |
544 | * still managed by arch specific suspend/resume code. | |
545 | */ | |
546 | static int timekeeping_resume(struct sys_device *dev) | |
547 | { | |
548 | unsigned long flags; | |
549 | unsigned long now = read_persistent_clock(); | |
550 | ||
d10ff3fb TG |
551 | clocksource_resume(); |
552 | ||
8524070b JS |
553 | write_seqlock_irqsave(&xtime_lock, flags); |
554 | ||
555 | if (now && (now > timekeeping_suspend_time)) { | |
556 | unsigned long sleep_length = now - timekeeping_suspend_time; | |
557 | ||
558 | xtime.tv_sec += sleep_length; | |
559 | wall_to_monotonic.tv_sec -= sleep_length; | |
7c3f1a57 | 560 | total_sleep_time += sleep_length; |
8524070b | 561 | } |
1001d0a9 | 562 | update_xtime_cache(0); |
8524070b | 563 | /* re-base the last cycle value */ |
155ec602 MS |
564 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
565 | timekeeper.ntp_error = 0; | |
8524070b JS |
566 | timekeeping_suspended = 0; |
567 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
568 | ||
569 | touch_softlockup_watchdog(); | |
570 | ||
571 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
572 | ||
573 | /* Resume hrtimers */ | |
574 | hres_timers_resume(); | |
575 | ||
576 | return 0; | |
577 | } | |
578 | ||
579 | static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) | |
580 | { | |
581 | unsigned long flags; | |
582 | ||
3be90950 TG |
583 | timekeeping_suspend_time = read_persistent_clock(); |
584 | ||
8524070b | 585 | write_seqlock_irqsave(&xtime_lock, flags); |
155ec602 | 586 | timekeeping_forward_now(); |
8524070b | 587 | timekeeping_suspended = 1; |
8524070b JS |
588 | write_sequnlock_irqrestore(&xtime_lock, flags); |
589 | ||
590 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
591 | ||
592 | return 0; | |
593 | } | |
594 | ||
595 | /* sysfs resume/suspend bits for timekeeping */ | |
596 | static struct sysdev_class timekeeping_sysclass = { | |
af5ca3f4 | 597 | .name = "timekeeping", |
8524070b JS |
598 | .resume = timekeeping_resume, |
599 | .suspend = timekeeping_suspend, | |
8524070b JS |
600 | }; |
601 | ||
602 | static struct sys_device device_timer = { | |
603 | .id = 0, | |
604 | .cls = &timekeeping_sysclass, | |
605 | }; | |
606 | ||
607 | static int __init timekeeping_init_device(void) | |
608 | { | |
609 | int error = sysdev_class_register(&timekeeping_sysclass); | |
610 | if (!error) | |
611 | error = sysdev_register(&device_timer); | |
612 | return error; | |
613 | } | |
614 | ||
615 | device_initcall(timekeeping_init_device); | |
616 | ||
617 | /* | |
618 | * If the error is already larger, we look ahead even further | |
619 | * to compensate for late or lost adjustments. | |
620 | */ | |
155ec602 | 621 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
8524070b JS |
622 | s64 *offset) |
623 | { | |
624 | s64 tick_error, i; | |
625 | u32 look_ahead, adj; | |
626 | s32 error2, mult; | |
627 | ||
628 | /* | |
629 | * Use the current error value to determine how much to look ahead. | |
630 | * The larger the error the slower we adjust for it to avoid problems | |
631 | * with losing too many ticks, otherwise we would overadjust and | |
632 | * produce an even larger error. The smaller the adjustment the | |
633 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 634 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
635 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
636 | */ | |
155ec602 | 637 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
638 | error2 = abs(error2); |
639 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
640 | error2 >>= 2; | |
641 | ||
642 | /* | |
643 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
644 | * remove the single look ahead already included in the error. | |
645 | */ | |
23ce7211 | 646 | tick_error = tick_length >> (timekeeper.ntp_error_shift + 1); |
155ec602 | 647 | tick_error -= timekeeper.xtime_interval >> 1; |
8524070b JS |
648 | error = ((error - tick_error) >> look_ahead) + tick_error; |
649 | ||
650 | /* Finally calculate the adjustment shift value. */ | |
651 | i = *interval; | |
652 | mult = 1; | |
653 | if (error < 0) { | |
654 | error = -error; | |
655 | *interval = -*interval; | |
656 | *offset = -*offset; | |
657 | mult = -1; | |
658 | } | |
659 | for (adj = 0; error > i; adj++) | |
660 | error >>= 1; | |
661 | ||
662 | *interval <<= adj; | |
663 | *offset <<= adj; | |
664 | return mult << adj; | |
665 | } | |
666 | ||
667 | /* | |
668 | * Adjust the multiplier to reduce the error value, | |
669 | * this is optimized for the most common adjustments of -1,0,1, | |
670 | * for other values we can do a bit more work. | |
671 | */ | |
155ec602 | 672 | static void timekeeping_adjust(s64 offset) |
8524070b | 673 | { |
155ec602 | 674 | s64 error, interval = timekeeper.cycle_interval; |
8524070b JS |
675 | int adj; |
676 | ||
23ce7211 | 677 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
8524070b JS |
678 | if (error > interval) { |
679 | error >>= 2; | |
680 | if (likely(error <= interval)) | |
681 | adj = 1; | |
682 | else | |
155ec602 | 683 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b JS |
684 | } else if (error < -interval) { |
685 | error >>= 2; | |
686 | if (likely(error >= -interval)) { | |
687 | adj = -1; | |
688 | interval = -interval; | |
689 | offset = -offset; | |
690 | } else | |
155ec602 | 691 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b JS |
692 | } else |
693 | return; | |
694 | ||
0a544198 | 695 | timekeeper.mult += adj; |
155ec602 MS |
696 | timekeeper.xtime_interval += interval; |
697 | timekeeper.xtime_nsec -= offset; | |
698 | timekeeper.ntp_error -= (interval - offset) << | |
23ce7211 | 699 | timekeeper.ntp_error_shift; |
8524070b JS |
700 | } |
701 | ||
702 | /** | |
703 | * update_wall_time - Uses the current clocksource to increment the wall time | |
704 | * | |
705 | * Called from the timer interrupt, must hold a write on xtime_lock. | |
706 | */ | |
707 | void update_wall_time(void) | |
708 | { | |
155ec602 | 709 | struct clocksource *clock; |
8524070b | 710 | cycle_t offset; |
23ce7211 | 711 | u64 nsecs; |
8524070b JS |
712 | |
713 | /* Make sure we're fully resumed: */ | |
714 | if (unlikely(timekeeping_suspended)) | |
715 | return; | |
716 | ||
155ec602 | 717 | clock = timekeeper.clock; |
8524070b | 718 | #ifdef CONFIG_GENERIC_TIME |
a0f7d48b | 719 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; |
8524070b | 720 | #else |
155ec602 | 721 | offset = timekeeper.cycle_interval; |
8524070b | 722 | #endif |
23ce7211 | 723 | timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; |
8524070b JS |
724 | |
725 | /* normally this loop will run just once, however in the | |
726 | * case of lost or late ticks, it will accumulate correctly. | |
727 | */ | |
155ec602 | 728 | while (offset >= timekeeper.cycle_interval) { |
23ce7211 | 729 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; |
155ec602 | 730 | |
8524070b | 731 | /* accumulate one interval */ |
155ec602 MS |
732 | offset -= timekeeper.cycle_interval; |
733 | clock->cycle_last += timekeeper.cycle_interval; | |
8524070b | 734 | |
155ec602 MS |
735 | timekeeper.xtime_nsec += timekeeper.xtime_interval; |
736 | if (timekeeper.xtime_nsec >= nsecps) { | |
737 | timekeeper.xtime_nsec -= nsecps; | |
8524070b JS |
738 | xtime.tv_sec++; |
739 | second_overflow(); | |
740 | } | |
741 | ||
155ec602 MS |
742 | raw_time.tv_nsec += timekeeper.raw_interval; |
743 | if (raw_time.tv_nsec >= NSEC_PER_SEC) { | |
744 | raw_time.tv_nsec -= NSEC_PER_SEC; | |
745 | raw_time.tv_sec++; | |
2d42244a JS |
746 | } |
747 | ||
8524070b | 748 | /* accumulate error between NTP and clock interval */ |
155ec602 MS |
749 | timekeeper.ntp_error += tick_length; |
750 | timekeeper.ntp_error -= timekeeper.xtime_interval << | |
23ce7211 | 751 | timekeeper.ntp_error_shift; |
8524070b JS |
752 | } |
753 | ||
754 | /* correct the clock when NTP error is too big */ | |
155ec602 | 755 | timekeeping_adjust(offset); |
8524070b | 756 | |
6c9bacb4 JS |
757 | /* |
758 | * Since in the loop above, we accumulate any amount of time | |
759 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
760 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
155ec602 | 761 | * slightly speeding the clocksource up in timekeeping_adjust(), |
6c9bacb4 JS |
762 | * its possible the required corrective factor to xtime_nsec could |
763 | * cause it to underflow. | |
764 | * | |
765 | * Now, we cannot simply roll the accumulated second back, since | |
766 | * the NTP subsystem has been notified via second_overflow. So | |
767 | * instead we push xtime_nsec forward by the amount we underflowed, | |
768 | * and add that amount into the error. | |
769 | * | |
770 | * We'll correct this error next time through this function, when | |
771 | * xtime_nsec is not as small. | |
772 | */ | |
155ec602 MS |
773 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
774 | s64 neg = -(s64)timekeeper.xtime_nsec; | |
775 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 776 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
6c9bacb4 JS |
777 | } |
778 | ||
5cd1c9c5 RZ |
779 | /* store full nanoseconds into xtime after rounding it up and |
780 | * add the remainder to the error difference. | |
781 | */ | |
23ce7211 MS |
782 | xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1; |
783 | timekeeper.xtime_nsec -= (s64) xtime.tv_nsec << timekeeper.shift; | |
784 | timekeeper.ntp_error += timekeeper.xtime_nsec << | |
785 | timekeeper.ntp_error_shift; | |
8524070b | 786 | |
0a544198 | 787 | nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift); |
155ec602 | 788 | update_xtime_cache(nsecs); |
17c38b74 | 789 | |
8524070b JS |
790 | /* check to see if there is a new clocksource to use */ |
791 | change_clocksource(); | |
155ec602 | 792 | update_vsyscall(&xtime, timekeeper.clock); |
8524070b | 793 | } |
7c3f1a57 TJ |
794 | |
795 | /** | |
796 | * getboottime - Return the real time of system boot. | |
797 | * @ts: pointer to the timespec to be set | |
798 | * | |
799 | * Returns the time of day in a timespec. | |
800 | * | |
801 | * This is based on the wall_to_monotonic offset and the total suspend | |
802 | * time. Calls to settimeofday will affect the value returned (which | |
803 | * basically means that however wrong your real time clock is at boot time, | |
804 | * you get the right time here). | |
805 | */ | |
806 | void getboottime(struct timespec *ts) | |
807 | { | |
808 | set_normalized_timespec(ts, | |
809 | - (wall_to_monotonic.tv_sec + total_sleep_time), | |
810 | - wall_to_monotonic.tv_nsec); | |
811 | } | |
812 | ||
813 | /** | |
814 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
815 | * @ts: pointer to the timespec to be converted | |
816 | */ | |
817 | void monotonic_to_bootbased(struct timespec *ts) | |
818 | { | |
819 | ts->tv_sec += total_sleep_time; | |
820 | } | |
2c6b47de | 821 | |
17c38b74 JS |
822 | unsigned long get_seconds(void) |
823 | { | |
824 | return xtime_cache.tv_sec; | |
825 | } | |
826 | EXPORT_SYMBOL(get_seconds); | |
827 | ||
828 | ||
2c6b47de JS |
829 | struct timespec current_kernel_time(void) |
830 | { | |
831 | struct timespec now; | |
832 | unsigned long seq; | |
833 | ||
834 | do { | |
835 | seq = read_seqbegin(&xtime_lock); | |
836 | ||
17c38b74 | 837 | now = xtime_cache; |
2c6b47de JS |
838 | } while (read_seqretry(&xtime_lock, seq)); |
839 | ||
840 | return now; | |
841 | } | |
2c6b47de | 842 | EXPORT_SYMBOL(current_kernel_time); |