2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
10 #include <sys/cdefs.h>
11 __FBSDID("$FreeBSD$");
15 #include <sys/param.h>
16 #include <sys/kernel.h>
17 #include <sys/sysctl.h>
18 #include <sys/syslog.h>
19 #include <sys/systm.h>
20 #include <sys/timepps.h>
21 #include <sys/timetc.h>
22 #include <sys/timex.h>
25 * A large step happens on boot. This constant detects such steps.
26 * It is relatively small so that ntp_update_second gets called enough
27 * in the typical 'missed a couple of seconds' case, but doesn't loop
28 * forever when the time step is large.
30 #define LARGE_STEP 200
33 * Implement a dummy timecounter which we can use until we get a real one
34 * in the air. This allows the console and other early stuff to use
39 dummy_get_timecount(struct timecounter
*tc
)
46 static struct timecounter dummy_timecounter
= {
47 dummy_get_timecount
, 0, ~0u, 1000000, "dummy", -1000000
51 /* These fields must be initialized by the driver. */
52 struct timecounter
*th_counter
;
53 int64_t th_adjustment
;
55 u_int th_offset_count
;
56 struct bintime th_offset
;
57 struct timeval th_microtime
;
58 struct timespec th_nanotime
;
59 /* Fields not to be copied in tc_windup start with th_generation. */
60 volatile u_int th_generation
;
61 struct timehands
*th_next
;
64 static struct timehands th0
;
65 static struct timehands th9
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0
};
66 static struct timehands th8
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9
};
67 static struct timehands th7
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8
};
68 static struct timehands th6
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7
};
69 static struct timehands th5
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6
};
70 static struct timehands th4
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5
};
71 static struct timehands th3
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4
};
72 static struct timehands th2
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3
};
73 static struct timehands th1
= { NULL
, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2
};
74 static struct timehands th0
= {
77 (uint64_t)-1 / 1000000,
86 static struct timehands
*volatile timehands
= &th0
;
87 struct timecounter
*timecounter
= &dummy_timecounter
;
88 static struct timecounter
*timecounters
= &dummy_timecounter
;
90 time_t time_second
= 1;
91 time_t time_uptime
= 1;
93 static struct bintime boottimebin
;
94 struct timeval boottime
;
95 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS
);
96 SYSCTL_PROC(_kern
, KERN_BOOTTIME
, boottime
, CTLTYPE_STRUCT
|CTLFLAG_RD
,
97 NULL
, 0, sysctl_kern_boottime
, "S,timeval", "System boottime");
99 SYSCTL_NODE(_kern
, OID_AUTO
, timecounter
, CTLFLAG_RW
, 0, "");
100 SYSCTL_NODE(_kern_timecounter
, OID_AUTO
, tc
, CTLFLAG_RW
, 0, "");
102 static int timestepwarnings
;
103 SYSCTL_INT(_kern_timecounter
, OID_AUTO
, stepwarnings
, CTLFLAG_RW
,
104 ×tepwarnings
, 0, "");
106 #define TC_STATS(foo) \
108 SYSCTL_UINT(_kern_timecounter, OID_AUTO, foo, CTLFLAG_RD, &foo, 0, "");\
111 TC_STATS(nbinuptime
); TC_STATS(nnanouptime
); TC_STATS(nmicrouptime
);
112 TC_STATS(nbintime
); TC_STATS(nnanotime
); TC_STATS(nmicrotime
);
113 TC_STATS(ngetbinuptime
); TC_STATS(ngetnanouptime
); TC_STATS(ngetmicrouptime
);
114 TC_STATS(ngetbintime
); TC_STATS(ngetnanotime
); TC_STATS(ngetmicrotime
);
119 static void tc_windup(void);
120 static void cpu_tick_calibrate(int);
123 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS
)
128 if (req
->flags
& SCTL_MASK32
) {
129 tv
[0] = boottime
.tv_sec
;
130 tv
[1] = boottime
.tv_usec
;
131 return SYSCTL_OUT(req
, tv
, sizeof(tv
));
134 return SYSCTL_OUT(req
, &boottime
, sizeof(boottime
));
138 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS
)
141 struct timecounter
*tc
= arg1
;
143 ncount
= tc
->tc_get_timecount(tc
);
144 return sysctl_handle_int(oidp
, &ncount
, 0, req
);
148 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS
)
151 struct timecounter
*tc
= arg1
;
153 freq
= tc
->tc_frequency
;
154 return sysctl_handle_quad(oidp
, &freq
, 0, req
);
158 * Return the difference between the timehands' counter value now and what
159 * was when we copied it to the timehands' offset_count.
161 static __inline u_int
162 tc_delta(struct timehands
*th
)
164 struct timecounter
*tc
;
167 return ((tc
->tc_get_timecount(tc
) - th
->th_offset_count
) &
168 tc
->tc_counter_mask
);
172 * Functions for reading the time. We have to loop until we are sure that
173 * the timehands that we operated on was not updated under our feet. See
174 * the comment in <sys/time.h> for a description of these 12 functions.
178 binuptime(struct bintime
*bt
)
180 struct timehands
*th
;
186 gen
= th
->th_generation
;
188 bintime_addx(bt
, th
->th_scale
* tc_delta(th
));
189 } while (gen
== 0 || gen
!= th
->th_generation
);
193 nanouptime(struct timespec
*tsp
)
199 bintime2timespec(&bt
, tsp
);
203 microuptime(struct timeval
*tvp
)
209 bintime2timeval(&bt
, tvp
);
213 bintime(struct bintime
*bt
)
218 bintime_add(bt
, &boottimebin
);
222 nanotime(struct timespec
*tsp
)
228 bintime2timespec(&bt
, tsp
);
232 microtime(struct timeval
*tvp
)
238 bintime2timeval(&bt
, tvp
);
242 getbinuptime(struct bintime
*bt
)
244 struct timehands
*th
;
250 gen
= th
->th_generation
;
252 } while (gen
== 0 || gen
!= th
->th_generation
);
256 getnanouptime(struct timespec
*tsp
)
258 struct timehands
*th
;
264 gen
= th
->th_generation
;
265 bintime2timespec(&th
->th_offset
, tsp
);
266 } while (gen
== 0 || gen
!= th
->th_generation
);
270 getmicrouptime(struct timeval
*tvp
)
272 struct timehands
*th
;
278 gen
= th
->th_generation
;
279 bintime2timeval(&th
->th_offset
, tvp
);
280 } while (gen
== 0 || gen
!= th
->th_generation
);
284 getbintime(struct bintime
*bt
)
286 struct timehands
*th
;
292 gen
= th
->th_generation
;
294 } while (gen
== 0 || gen
!= th
->th_generation
);
295 bintime_add(bt
, &boottimebin
);
299 getnanotime(struct timespec
*tsp
)
301 struct timehands
*th
;
307 gen
= th
->th_generation
;
308 *tsp
= th
->th_nanotime
;
309 } while (gen
== 0 || gen
!= th
->th_generation
);
313 getmicrotime(struct timeval
*tvp
)
315 struct timehands
*th
;
321 gen
= th
->th_generation
;
322 *tvp
= th
->th_microtime
;
323 } while (gen
== 0 || gen
!= th
->th_generation
);
327 * Initialize a new timecounter and possibly use it.
330 tc_init(struct timecounter
*tc
)
333 struct sysctl_oid
*tc_root
;
335 u
= tc
->tc_frequency
/ tc
->tc_counter_mask
;
336 /* XXX: We need some margin here, 10% is a guess */
339 if (u
> hz
&& tc
->tc_quality
>= 0) {
340 tc
->tc_quality
= -2000;
342 printf("Timecounter \"%s\" frequency %ju Hz",
343 tc
->tc_name
, (uintmax_t)tc
->tc_frequency
);
344 printf(" -- Insufficient hz, needs at least %u\n", u
);
346 } else if (tc
->tc_quality
>= 0 || bootverbose
) {
347 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
348 tc
->tc_name
, (uintmax_t)tc
->tc_frequency
,
352 tc
->tc_next
= timecounters
;
355 * Set up sysctl tree for this counter.
357 tc_root
= SYSCTL_ADD_NODE(NULL
,
358 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc
), OID_AUTO
, tc
->tc_name
,
359 CTLFLAG_RW
, 0, "timecounter description");
360 SYSCTL_ADD_UINT(NULL
, SYSCTL_CHILDREN(tc_root
), OID_AUTO
,
361 "mask", CTLFLAG_RD
, &(tc
->tc_counter_mask
), 0,
362 "mask for implemented bits");
363 SYSCTL_ADD_PROC(NULL
, SYSCTL_CHILDREN(tc_root
), OID_AUTO
,
364 "counter", CTLTYPE_UINT
| CTLFLAG_RD
, tc
, sizeof(*tc
),
365 sysctl_kern_timecounter_get
, "IU", "current timecounter value");
366 SYSCTL_ADD_PROC(NULL
, SYSCTL_CHILDREN(tc_root
), OID_AUTO
,
367 "frequency", CTLTYPE_QUAD
| CTLFLAG_RD
, tc
, sizeof(*tc
),
368 sysctl_kern_timecounter_freq
, "QU", "timecounter frequency");
369 SYSCTL_ADD_INT(NULL
, SYSCTL_CHILDREN(tc_root
), OID_AUTO
,
370 "quality", CTLFLAG_RD
, &(tc
->tc_quality
), 0,
371 "goodness of time counter");
373 * Never automatically use a timecounter with negative quality.
374 * Even though we run on the dummy counter, switching here may be
375 * worse since this timecounter may not be monotonous.
377 if (tc
->tc_quality
< 0)
379 if (tc
->tc_quality
< timecounter
->tc_quality
)
381 if (tc
->tc_quality
== timecounter
->tc_quality
&&
382 tc
->tc_frequency
< timecounter
->tc_frequency
)
384 (void)tc
->tc_get_timecount(tc
);
385 (void)tc
->tc_get_timecount(tc
);
389 /* Report the frequency of the current timecounter. */
391 tc_getfrequency(void)
394 return (timehands
->th_counter
->tc_frequency
);
398 * Step our concept of UTC. This is done by modifying our estimate of
403 tc_setclock(struct timespec
*ts
)
405 struct timespec tbef
, taft
;
406 struct bintime bt
, bt2
;
408 cpu_tick_calibrate(1);
411 timespec2bintime(ts
, &bt
);
413 bintime_sub(&bt
, &bt2
);
414 bintime_add(&bt2
, &boottimebin
);
416 bintime2timeval(&bt
, &boottime
);
418 /* XXX fiddle all the little crinkly bits around the fiords... */
421 if (timestepwarnings
) {
423 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
424 (intmax_t)tbef
.tv_sec
, tbef
.tv_nsec
,
425 (intmax_t)taft
.tv_sec
, taft
.tv_nsec
,
426 (intmax_t)ts
->tv_sec
, ts
->tv_nsec
);
428 cpu_tick_calibrate(1);
432 * Initialize the next struct timehands in the ring and make
433 * it the active timehands. Along the way we might switch to a different
434 * timecounter and/or do seconds processing in NTP. Slightly magic.
440 struct timehands
*th
, *tho
;
442 u_int delta
, ncount
, ogen
;
447 * Make the next timehands a copy of the current one, but do not
448 * overwrite the generation or next pointer. While we update
449 * the contents, the generation must be zero.
453 ogen
= th
->th_generation
;
454 th
->th_generation
= 0;
455 bcopy(tho
, th
, offsetof(struct timehands
, th_generation
));
458 * Capture a timecounter delta on the current timecounter and if
459 * changing timecounters, a counter value from the new timecounter.
460 * Update the offset fields accordingly.
462 delta
= tc_delta(th
);
463 if (th
->th_counter
!= timecounter
)
464 ncount
= timecounter
->tc_get_timecount(timecounter
);
467 th
->th_offset_count
+= delta
;
468 th
->th_offset_count
&= th
->th_counter
->tc_counter_mask
;
469 bintime_addx(&th
->th_offset
, th
->th_scale
* delta
);
472 * Hardware latching timecounters may not generate interrupts on
473 * PPS events, so instead we poll them. There is a finite risk that
474 * the hardware might capture a count which is later than the one we
475 * got above, and therefore possibly in the next NTP second which might
476 * have a different rate than the current NTP second. It doesn't
477 * matter in practice.
479 if (tho
->th_counter
->tc_poll_pps
)
480 tho
->th_counter
->tc_poll_pps(tho
->th_counter
);
483 * Deal with NTP second processing. The for loop normally
484 * iterates at most once, but in extreme situations it might
485 * keep NTP sane if timeouts are not run for several seconds.
486 * At boot, the time step can be large when the TOD hardware
487 * has been read, so on really large steps, we call
488 * ntp_update_second only twice. We need to call it twice in
489 * case we missed a leap second.
492 bintime_add(&bt
, &boottimebin
);
493 i
= bt
.sec
- tho
->th_microtime
.tv_sec
;
498 ntp_update_second(&th
->th_adjustment
, &bt
.sec
);
500 boottimebin
.sec
+= bt
.sec
- t
;
502 /* Update the UTC timestamps used by the get*() functions. */
503 /* XXX shouldn't do this here. Should force non-`get' versions. */
504 bintime2timeval(&bt
, &th
->th_microtime
);
505 bintime2timespec(&bt
, &th
->th_nanotime
);
507 /* Now is a good time to change timecounters. */
508 if (th
->th_counter
!= timecounter
) {
509 th
->th_counter
= timecounter
;
510 th
->th_offset_count
= ncount
;
514 * Recalculate the scaling factor. We want the number of 1/2^64
515 * fractions of a second per period of the hardware counter, taking
516 * into account the th_adjustment factor which the NTP PLL/adjtime(2)
517 * processing provides us with.
519 * The th_adjustment is nanoseconds per second with 32 bit binary
520 * fraction and we want 64 bit binary fraction of second:
522 * x = a * 2^32 / 10^9 = a * 4.294967296
524 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
525 * we can only multiply by about 850 without overflowing, that
526 * leaves no suitably precise fractions for multiply before divide.
528 * Divide before multiply with a fraction of 2199/512 results in a
529 * systematic undercompensation of 10PPM of th_adjustment. On a
530 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
532 * We happily sacrifice the lowest of the 64 bits of our result
533 * to the goddess of code clarity.
536 scale
= (u_int64_t
)1 << 63;
537 scale
+= (th
->th_adjustment
/ 1024) * 2199;
538 scale
/= th
->th_counter
->tc_frequency
;
539 th
->th_scale
= scale
* 2;
542 * Now that the struct timehands is again consistent, set the new
543 * generation number, making sure to not make it zero.
547 th
->th_generation
= ogen
;
549 /* Go live with the new struct timehands. */
550 time_second
= th
->th_microtime
.tv_sec
;
551 time_uptime
= th
->th_offset
.sec
;
555 /* Report or change the active timecounter hardware. */
557 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS
)
560 struct timecounter
*newtc
, *tc
;
564 strlcpy(newname
, tc
->tc_name
, sizeof(newname
));
566 error
= sysctl_handle_string(oidp
, &newname
[0], sizeof(newname
), req
);
567 if (error
!= 0 || req
->newptr
== NULL
||
568 strcmp(newname
, tc
->tc_name
) == 0)
570 for (newtc
= timecounters
; newtc
!= NULL
; newtc
= newtc
->tc_next
) {
571 if (strcmp(newname
, newtc
->tc_name
) != 0)
574 /* Warm up new timecounter. */
575 (void)newtc
->tc_get_timecount(newtc
);
576 (void)newtc
->tc_get_timecount(newtc
);
584 SYSCTL_PROC(_kern_timecounter
, OID_AUTO
, hardware
, CTLTYPE_STRING
| CTLFLAG_RW
,
585 0, 0, sysctl_kern_timecounter_hardware
, "A", "");
588 /* Report or change the active timecounter hardware. */
590 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS
)
593 struct timecounter
*tc
;
598 for (tc
= timecounters
; error
== 0 && tc
!= NULL
; tc
= tc
->tc_next
) {
599 sprintf(buf
, "%s%s(%d)",
600 spc
, tc
->tc_name
, tc
->tc_quality
);
601 error
= SYSCTL_OUT(req
, buf
, strlen(buf
));
607 SYSCTL_PROC(_kern_timecounter
, OID_AUTO
, choice
, CTLTYPE_STRING
| CTLFLAG_RD
,
608 0, 0, sysctl_kern_timecounter_choice
, "A", "");
611 * RFC 2783 PPS-API implementation.
615 pps_ioctl(u_long cmd
, caddr_t data
, struct pps_state
*pps
)
618 struct pps_fetch_args
*fapi
;
620 struct pps_kcbind_args
*kapi
;
623 KASSERT(pps
!= NULL
, ("NULL pps pointer in pps_ioctl"));
627 case PPS_IOC_DESTROY
:
629 case PPS_IOC_SETPARAMS
:
630 app
= (pps_params_t
*)data
;
631 if (app
->mode
& ~pps
->ppscap
)
633 pps
->ppsparam
= *app
;
635 case PPS_IOC_GETPARAMS
:
636 app
= (pps_params_t
*)data
;
637 *app
= pps
->ppsparam
;
638 app
->api_version
= PPS_API_VERS_1
;
641 *(int*)data
= pps
->ppscap
;
644 fapi
= (struct pps_fetch_args
*)data
;
645 if (fapi
->tsformat
&& fapi
->tsformat
!= PPS_TSFMT_TSPEC
)
647 if (fapi
->timeout
.tv_sec
|| fapi
->timeout
.tv_nsec
)
649 pps
->ppsinfo
.current_mode
= pps
->ppsparam
.mode
;
650 fapi
->pps_info_buf
= pps
->ppsinfo
;
654 kapi
= (struct pps_kcbind_args
*)data
;
655 /* XXX Only root should be able to do this */
656 if (kapi
->tsformat
&& kapi
->tsformat
!= PPS_TSFMT_TSPEC
)
658 if (kapi
->kernel_consumer
!= PPS_KC_HARDPPS
)
660 if (kapi
->edge
& ~pps
->ppscap
)
662 pps
->kcmode
= kapi
->edge
;
673 pps_init(struct pps_state
*pps
)
675 pps
->ppscap
|= PPS_TSFMT_TSPEC
;
676 if (pps
->ppscap
& PPS_CAPTUREASSERT
)
677 pps
->ppscap
|= PPS_OFFSETASSERT
;
678 if (pps
->ppscap
& PPS_CAPTURECLEAR
)
679 pps
->ppscap
|= PPS_OFFSETCLEAR
;
683 pps_capture(struct pps_state
*pps
)
685 struct timehands
*th
;
687 KASSERT(pps
!= NULL
, ("NULL pps pointer in pps_capture"));
689 pps
->capgen
= th
->th_generation
;
691 pps
->capcount
= th
->th_counter
->tc_get_timecount(th
->th_counter
);
692 if (pps
->capgen
!= th
->th_generation
)
697 pps_event(struct pps_state
*pps
, int event
)
700 struct timespec ts
, *tsp
, *osp
;
701 u_int tcount
, *pcount
;
705 KASSERT(pps
!= NULL
, ("NULL pps pointer in pps_event"));
706 /* If the timecounter was wound up underneath us, bail out. */
707 if (pps
->capgen
== 0 || pps
->capgen
!= pps
->capth
->th_generation
)
710 /* Things would be easier with arrays. */
711 if (event
== PPS_CAPTUREASSERT
) {
712 tsp
= &pps
->ppsinfo
.assert_timestamp
;
713 osp
= &pps
->ppsparam
.assert_offset
;
714 foff
= pps
->ppsparam
.mode
& PPS_OFFSETASSERT
;
715 fhard
= pps
->kcmode
& PPS_CAPTUREASSERT
;
716 pcount
= &pps
->ppscount
[0];
717 pseq
= &pps
->ppsinfo
.assert_sequence
;
719 tsp
= &pps
->ppsinfo
.clear_timestamp
;
720 osp
= &pps
->ppsparam
.clear_offset
;
721 foff
= pps
->ppsparam
.mode
& PPS_OFFSETCLEAR
;
722 fhard
= pps
->kcmode
& PPS_CAPTURECLEAR
;
723 pcount
= &pps
->ppscount
[1];
724 pseq
= &pps
->ppsinfo
.clear_sequence
;
728 * If the timecounter changed, we cannot compare the count values, so
729 * we have to drop the rest of the PPS-stuff until the next event.
731 if (pps
->ppstc
!= pps
->capth
->th_counter
) {
732 pps
->ppstc
= pps
->capth
->th_counter
;
733 *pcount
= pps
->capcount
;
734 pps
->ppscount
[2] = pps
->capcount
;
738 /* Convert the count to a timespec. */
739 tcount
= pps
->capcount
- pps
->capth
->th_offset_count
;
740 tcount
&= pps
->capth
->th_counter
->tc_counter_mask
;
741 bt
= pps
->capth
->th_offset
;
742 bintime_addx(&bt
, pps
->capth
->th_scale
* tcount
);
743 bintime_add(&bt
, &boottimebin
);
744 bintime2timespec(&bt
, &ts
);
746 /* If the timecounter was wound up underneath us, bail out. */
747 if (pps
->capgen
!= pps
->capth
->th_generation
)
750 *pcount
= pps
->capcount
;
755 timespecadd(tsp
, osp
);
756 if (tsp
->tv_nsec
< 0) {
757 tsp
->tv_nsec
+= 1000000000;
766 * Feed the NTP PLL/FLL.
767 * The FLL wants to know how many (hardware) nanoseconds
768 * elapsed since the previous event.
770 tcount
= pps
->capcount
- pps
->ppscount
[2];
771 pps
->ppscount
[2] = pps
->capcount
;
772 tcount
&= pps
->capth
->th_counter
->tc_counter_mask
;
773 scale
= (u_int64_t
)1 << 63;
774 scale
/= pps
->capth
->th_counter
->tc_frequency
;
778 bintime_addx(&bt
, scale
* tcount
);
779 bintime2timespec(&bt
, &ts
);
780 hardpps(tsp
, ts
.tv_nsec
+ 1000000000 * ts
.tv_sec
);
786 * Timecounters need to be updated every so often to prevent the hardware
787 * counter from overflowing. Updating also recalculates the cached values
788 * used by the get*() family of functions, so their precision depends on
789 * the update frequency.
793 SYSCTL_INT(_kern_timecounter
, OID_AUTO
, tick
, CTLFLAG_RD
, &tc_tick
, 0, "");
799 static time_t last_calib
;
801 if (++count
< tc_tick
)
805 if (time_uptime
!= last_calib
&& !(time_uptime
& 0xf)) {
806 cpu_tick_calibrate(0);
807 last_calib
= time_uptime
;
812 inittimecounter(void *dummy
)
817 * Set the initial timeout to
818 * max(1, <approx. number of hardclock ticks in a millisecond>).
819 * People should probably not use the sysctl to set the timeout
820 * to smaller than its inital value, since that value is the
821 * smallest reasonable one. If they want better timestamps they
822 * should use the non-"get"* functions.
825 tc_tick
= (hz
+ 500) / 1000;
828 p
= (tc_tick
* 1000000) / hz
;
829 printf("Timecounters tick every %d.%03u msec\n", p
/ 1000, p
% 1000);
831 /* warm up new timecounter (again) and get rolling. */
832 (void)timecounter
->tc_get_timecount(timecounter
);
833 (void)timecounter
->tc_get_timecount(timecounter
);
836 SYSINIT(timecounter
, SI_SUB_CLOCKS
, SI_ORDER_SECOND
, inittimecounter
, NULL
);
838 /* Cpu tick handling -------------------------------------------------*/
840 static int cpu_tick_variable
;
841 static uint64_t cpu_tick_frequency
;
846 static uint64_t base
;
847 static unsigned last
;
849 struct timecounter
*tc
;
851 tc
= timehands
->th_counter
;
852 u
= tc
->tc_get_timecount(tc
) & tc
->tc_counter_mask
;
854 base
+= (uint64_t)tc
->tc_counter_mask
+ 1;
860 * This function gets called every 16 seconds on only one designated
861 * CPU in the system from hardclock() via tc_ticktock().
863 * Whenever the real time clock is stepped we get called with reset=1
864 * to make sure we handle suspend/resume and similar events correctly.
868 cpu_tick_calibrate(int reset
)
870 static uint64_t c_last
;
871 uint64_t c_this
, c_delta
;
872 static struct bintime t_last
;
873 struct bintime t_this
, t_delta
;
877 /* The clock was stepped, abort & reset */
882 /* we don't calibrate fixed rate cputicks */
883 if (!cpu_tick_variable
)
886 getbinuptime(&t_this
);
887 c_this
= cpu_ticks();
888 if (t_last
.sec
!= 0) {
889 c_delta
= c_this
- c_last
;
891 bintime_sub(&t_delta
, &t_last
);
893 * Validate that 16 +/- 1/256 seconds passed.
894 * After division by 16 this gives us a precision of
895 * roughly 250PPM which is sufficient
897 if (t_delta
.sec
> 16 || (
898 t_delta
.sec
== 16 && t_delta
.frac
>= (0x01LL
<< 56))) {
901 printf("t_delta %ju.%016jx too long\n",
902 (uintmax_t)t_delta
.sec
,
903 (uintmax_t)t_delta
.frac
);
904 } else if (t_delta
.sec
< 15 ||
905 (t_delta
.sec
== 15 && t_delta
.frac
<= (0xffLL
<< 56))) {
908 printf("t_delta %ju.%016jx too short\n",
909 (uintmax_t)t_delta
.sec
,
910 (uintmax_t)t_delta
.frac
);
915 * 2^(64-20) / 16[s] =
917 * 17.592.186.044.416 / 16 =
918 * 1.099.511.627.776 [Hz]
920 divi
= t_delta
.sec
<< 20;
921 divi
|= t_delta
.frac
>> (64 - 20);
924 if (c_delta
> cpu_tick_frequency
) {
925 if (0 && bootverbose
)
926 printf("cpu_tick increased to %ju Hz\n",
928 cpu_tick_frequency
= c_delta
;
937 set_cputicker(cpu_tick_f
*func
, uint64_t freq
, unsigned var
)
941 cpu_ticks
= tc_cpu_ticks
;
943 cpu_tick_frequency
= freq
;
944 cpu_tick_variable
= var
;
953 if (cpu_ticks
== tc_cpu_ticks
)
954 return (tc_getfrequency());
955 return (cpu_tick_frequency
);
959 * We need to be slightly careful converting cputicks to microseconds.
960 * There is plenty of margin in 64 bits of microseconds (half a million
961 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
962 * before divide conversion (to retain precision) we find that the
963 * margin shrinks to 1.5 hours (one millionth of 146y).
964 * With a three prong approach we never lose significant bits, no
965 * matter what the cputick rate and length of timeinterval is.
969 cputick2usec(uint64_t tick
)
972 if (tick
> 18446744073709551LL) /* floor(2^64 / 1000) */
973 return (tick
/ (cpu_tickrate() / 1000000LL));
974 else if (tick
> 18446744073709LL) /* floor(2^64 / 1000000) */
975 return ((tick
* 1000LL) / (cpu_tickrate() / 1000LL));
977 return ((tick
* 1000000LL) / cpu_tickrate());
980 cpu_tick_f
*cpu_ticks
= tc_cpu_ticks
;