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