2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2011 The University of Melbourne
7 * This software was developed by Julien Ridoux at the University of Melbourne
8 * under sponsorship from the FreeBSD Foundation.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #ifndef _SYS_TIMEFF_H_
35 #define _SYS_TIMEFF_H_
37 #include <sys/_ffcounter.h>
40 * Feed-forward clock estimate
41 * Holds time mark as a ffcounter and conversion to bintime based on current
42 * timecounter period and offset estimate passed by the synchronization daemon.
43 * Provides time of last daemon update, clock status and bound on error.
45 struct ffclock_estimate {
46 struct bintime update_time; /* Time of last estimates update. */
47 ffcounter update_ffcount; /* Counter value at last update. */
48 ffcounter leapsec_next; /* Counter value of next leap second. */
49 uint64_t period; /* Estimate of counter period. */
50 uint32_t errb_abs; /* Bound on absolute clock error [ns]. */
51 uint32_t errb_rate; /* Bound on counter rate error [ps/s]. */
52 uint32_t status; /* Clock status. */
53 int16_t leapsec_total; /* All leap seconds seen so far. */
54 int8_t leapsec; /* Next leap second (in {-1,0,1}). */
60 /* Define the kern.sysclock sysctl tree. */
61 SYSCTL_DECL(_kern_sysclock);
63 /* Define the kern.sysclock.ffclock sysctl tree. */
64 SYSCTL_DECL(_kern_sysclock_ffclock);
67 * Index into the sysclocks array for obtaining the ASCII name of a particular
70 #define SYSCLOCK_FBCK 0
71 #define SYSCLOCK_FFWD 1
72 extern int sysclock_active;
75 * Parameters of counter characterisation required by feed-forward algorithms.
77 #define FFCLOCK_SKM_SCALE 1024
80 * Feed-forward clock status
82 #define FFCLOCK_STA_UNSYNC 1
83 #define FFCLOCK_STA_WARMUP 2
86 * Flags for use by sysclock_snap2bintime() and various ffclock_ functions to
87 * control how the timecounter hardware is read and how the hardware snapshot is
88 * converted into absolute time.
89 * {FB|FF}CLOCK_FAST: Do not read the hardware counter, instead using the
90 * value at last tick. The time returned has a resolution
91 * of the kernel tick timer (1/hz [s]).
92 * FFCLOCK_LERP: Linear interpolation of ffclock time to guarantee
94 * FFCLOCK_LEAPSEC: Include leap seconds.
95 * {FB|FF}CLOCK_UPTIME: Time stamp should be relative to system boot, not epoch.
97 #define FFCLOCK_FAST 0x00000001
98 #define FFCLOCK_LERP 0x00000002
99 #define FFCLOCK_LEAPSEC 0x00000004
100 #define FFCLOCK_UPTIME 0x00000008
101 #define FFCLOCK_MASK 0x0000ffff
103 #define FBCLOCK_FAST 0x00010000 /* Currently unused. */
104 #define FBCLOCK_UPTIME 0x00020000
105 #define FBCLOCK_MASK 0xffff0000
108 * Feedback clock specific info structure. The feedback clock's estimation of
109 * clock error is an absolute figure determined by the NTP algorithm. The status
110 * is determined by the userland daemon.
112 struct fbclock_info {
113 struct bintime error;
114 struct bintime tick_time;
120 * Feed-forward clock specific info structure. The feed-forward clock's
121 * estimation of clock error is an upper bound, which although potentially
122 * looser than the feedback clock equivalent, is much more reliable. The status
123 * is determined by the userland daemon.
125 struct ffclock_info {
126 struct bintime error;
127 struct bintime tick_time;
128 struct bintime tick_time_lerp;
130 uint64_t period_lerp;
131 int leapsec_adjustment;
136 * Snapshot of system clocks and related information. Holds time read from each
137 * clock based on a single read of the active hardware timecounter, as well as
138 * respective clock information such as error estimates and the ffcounter value
139 * at the time of the read.
141 struct sysclock_snap {
142 struct fbclock_info fb_info;
143 struct ffclock_info ff_info;
149 /* Take a snapshot of the system clocks and related information. */
150 void sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast);
152 /* Convert a timestamp from the selected system clock into bintime. */
153 int sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt,
154 int whichclock, uint32_t flags);
156 /* Resets feed-forward clock from RTC */
157 void ffclock_reset_clock(struct timespec *ts);
160 * Return the current value of the feed-forward clock counter. Essential to
161 * measure time interval in counter units. If a fast timecounter is used by the
162 * system, may also allow fast but accurate timestamping.
164 void ffclock_read_counter(ffcounter *ffcount);
167 * Retrieve feed-forward counter value and time of last kernel tick. This
168 * accepts the FFCLOCK_LERP flag.
170 void ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags);
173 * Low level routines to convert a counter timestamp into absolute time and a
174 * counter timestamp interval into an interval in seconds. The absolute time
175 * conversion accepts the FFCLOCK_LERP flag.
177 void ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags);
178 void ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt);
181 * Feed-forward clock routines.
183 * These functions rely on the timecounters and ffclock_estimates stored in
184 * fftimehands. Note that the error_bound parameter is not the error of the
185 * clock but an upper bound on the error of the absolute time or time interval
188 * ffclock_abstime(): retrieves current time as counter value and convert this
189 * timestamp in seconds. The value (in seconds) of the converted timestamp
190 * depends on the flags passed: for a given counter value, different
191 * conversions are possible. Different clock models can be selected by
192 * combining flags (for example (FFCLOCK_LERP|FFCLOCK_UPTIME) produces
193 * linearly interpolated uptime).
194 * ffclock_difftime(): computes a time interval in seconds based on an interval
195 * measured in ffcounter units. This should be the preferred way to measure
196 * small time intervals very accurately.
198 void ffclock_abstime(ffcounter *ffcount, struct bintime *bt,
199 struct bintime *error_bound, uint32_t flags);
200 void ffclock_difftime(ffcounter ffdelta, struct bintime *bt,
201 struct bintime *error_bound);
204 * Wrapper routines to return current absolute time using the feed-forward
205 * clock. These functions are named after those defined in <sys/time.h>, which
206 * contains a description of the original ones.
208 void ffclock_bintime(struct bintime *bt);
209 void ffclock_nanotime(struct timespec *tsp);
210 void ffclock_microtime(struct timeval *tvp);
212 void ffclock_getbintime(struct bintime *bt);
213 void ffclock_getnanotime(struct timespec *tsp);
214 void ffclock_getmicrotime(struct timeval *tvp);
216 void ffclock_binuptime(struct bintime *bt);
217 void ffclock_nanouptime(struct timespec *tsp);
218 void ffclock_microuptime(struct timeval *tvp);
220 void ffclock_getbinuptime(struct bintime *bt);
221 void ffclock_getnanouptime(struct timespec *tsp);
222 void ffclock_getmicrouptime(struct timeval *tvp);
225 * Wrapper routines to convert a time interval specified in ffcounter units into
226 * seconds using the current feed-forward clock estimates.
228 void ffclock_bindifftime(ffcounter ffdelta, struct bintime *bt);
229 void ffclock_nanodifftime(ffcounter ffdelta, struct timespec *tsp);
230 void ffclock_microdifftime(ffcounter ffdelta, struct timeval *tvp);
233 * When FFCLOCK is enabled in the kernel, [get]{bin,nano,micro}[up]time() become
234 * wrappers around equivalent feedback or feed-forward functions. Provide access
235 * outside of kern_tc.c to the feedback clock equivalent functions for
236 * specialised use i.e. these are not for general consumption.
238 void fbclock_bintime(struct bintime *bt);
239 void fbclock_nanotime(struct timespec *tsp);
240 void fbclock_microtime(struct timeval *tvp);
242 void fbclock_getbintime(struct bintime *bt);
243 void fbclock_getnanotime(struct timespec *tsp);
244 void fbclock_getmicrotime(struct timeval *tvp);
246 void fbclock_binuptime(struct bintime *bt);
247 void fbclock_nanouptime(struct timespec *tsp);
248 void fbclock_microuptime(struct timeval *tvp);
250 void fbclock_getbinuptime(struct bintime *bt);
251 void fbclock_getnanouptime(struct timespec *tsp);
252 void fbclock_getmicrouptime(struct timeval *tvp);
255 * Public system clock wrapper API which allows consumers to select which clock
256 * to obtain time from, independent of the current default system clock. These
257 * wrappers should be used instead of directly calling the underlying fbclock_
258 * or ffclock_ functions.
261 bintime_fromclock(struct bintime *bt, int whichclock)
264 if (whichclock == SYSCLOCK_FFWD)
271 nanotime_fromclock(struct timespec *tsp, int whichclock)
274 if (whichclock == SYSCLOCK_FFWD)
275 ffclock_nanotime(tsp);
277 fbclock_nanotime(tsp);
281 microtime_fromclock(struct timeval *tvp, int whichclock)
284 if (whichclock == SYSCLOCK_FFWD)
285 ffclock_microtime(tvp);
287 fbclock_microtime(tvp);
291 getbintime_fromclock(struct bintime *bt, int whichclock)
294 if (whichclock == SYSCLOCK_FFWD)
295 ffclock_getbintime(bt);
297 fbclock_getbintime(bt);
301 getnanotime_fromclock(struct timespec *tsp, int whichclock)
304 if (whichclock == SYSCLOCK_FFWD)
305 ffclock_getnanotime(tsp);
307 fbclock_getnanotime(tsp);
311 getmicrotime_fromclock(struct timeval *tvp, int whichclock)
314 if (whichclock == SYSCLOCK_FFWD)
315 ffclock_getmicrotime(tvp);
317 fbclock_getmicrotime(tvp);
321 binuptime_fromclock(struct bintime *bt, int whichclock)
324 if (whichclock == SYSCLOCK_FFWD)
325 ffclock_binuptime(bt);
327 fbclock_binuptime(bt);
331 nanouptime_fromclock(struct timespec *tsp, int whichclock)
334 if (whichclock == SYSCLOCK_FFWD)
335 ffclock_nanouptime(tsp);
337 fbclock_nanouptime(tsp);
341 microuptime_fromclock(struct timeval *tvp, int whichclock)
344 if (whichclock == SYSCLOCK_FFWD)
345 ffclock_microuptime(tvp);
347 fbclock_microuptime(tvp);
351 getbinuptime_fromclock(struct bintime *bt, int whichclock)
354 if (whichclock == SYSCLOCK_FFWD)
355 ffclock_getbinuptime(bt);
357 fbclock_getbinuptime(bt);
361 getnanouptime_fromclock(struct timespec *tsp, int whichclock)
364 if (whichclock == SYSCLOCK_FFWD)
365 ffclock_getnanouptime(tsp);
367 fbclock_getnanouptime(tsp);
371 getmicrouptime_fromclock(struct timeval *tvp, int whichclock)
374 if (whichclock == SYSCLOCK_FFWD)
375 ffclock_getmicrouptime(tvp);
377 fbclock_getmicrouptime(tvp);
382 /* Feed-Forward Clock system calls. */
384 int ffclock_getcounter(ffcounter *ffcount);
385 int ffclock_getestimate(struct ffclock_estimate *cest);
386 int ffclock_setestimate(struct ffclock_estimate *cest);
390 #endif /* __BSD_VISIBLE */
391 #endif /* _SYS_TIMEFF_H_ */