2 * Copyright (c) 2011 The University of Melbourne
5 * This software was developed by Julien Ridoux at the University of Melbourne
6 * under sponsorship from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #ifndef _SYS_TIMEFF_H_
33 #define _SYS_TIMEFF_H_
35 #include <sys/_ffcounter.h>
38 * Feed-forward clock estimate
39 * Holds time mark as a ffcounter and conversion to bintime based on current
40 * timecounter period and offset estimate passed by the synchronization daemon.
41 * Provides time of last daemon update, clock status and bound on error.
43 struct ffclock_estimate {
44 struct bintime update_time; /* Time of last estimates update. */
45 ffcounter update_ffcount; /* Counter value at last update. */
46 ffcounter leapsec_next; /* Counter value of next leap second. */
47 uint64_t period; /* Estimate of counter period. */
48 uint32_t errb_abs; /* Bound on absolute clock error [ns]. */
49 uint32_t errb_rate; /* Bound on counter rate error [ps/s]. */
50 uint32_t status; /* Clock status. */
51 int16_t leapsec_total; /* All leap seconds seen so far. */
52 int8_t leapsec; /* Next leap second (in {-1,0,1}). */
58 /* Define the kern.sysclock sysctl tree. */
59 SYSCTL_DECL(_kern_sysclock);
61 /* Define the kern.sysclock.ffclock sysctl tree. */
62 SYSCTL_DECL(_kern_sysclock_ffclock);
65 * Index into the sysclocks array for obtaining the ASCII name of a particular
68 #define SYSCLOCK_FBCK 0
69 #define SYSCLOCK_FFWD 1
70 extern int sysclock_active;
73 * Parameters of counter characterisation required by feed-forward algorithms.
75 #define FFCLOCK_SKM_SCALE 1024
78 * Feed-forward clock status
80 #define FFCLOCK_STA_UNSYNC 1
81 #define FFCLOCK_STA_WARMUP 2
84 * Flags for use by sysclock_snap2bintime() and various ffclock_ functions to
85 * control how the timecounter hardware is read and how the hardware snapshot is
86 * converted into absolute time.
87 * {FB|FF}CLOCK_FAST: Do not read the hardware counter, instead using the
88 * value at last tick. The time returned has a resolution
89 * of the kernel tick timer (1/hz [s]).
90 * FFCLOCK_LERP: Linear interpolation of ffclock time to guarantee
92 * FFCLOCK_LEAPSEC: Include leap seconds.
93 * {FB|FF}CLOCK_UPTIME: Time stamp should be relative to system boot, not epoch.
95 #define FFCLOCK_FAST 0x00000001
96 #define FFCLOCK_LERP 0x00000002
97 #define FFCLOCK_LEAPSEC 0x00000004
98 #define FFCLOCK_UPTIME 0x00000008
99 #define FFCLOCK_MASK 0x0000ffff
101 #define FBCLOCK_FAST 0x00010000 /* Currently unused. */
102 #define FBCLOCK_UPTIME 0x00020000
103 #define FBCLOCK_MASK 0xffff0000
106 * Feedback clock specific info structure. The feedback clock's estimation of
107 * clock error is an absolute figure determined by the NTP algorithm. The status
108 * is determined by the userland daemon.
110 struct fbclock_info {
111 struct bintime error;
112 struct bintime tick_time;
118 * Feed-forward clock specific info structure. The feed-forward clock's
119 * estimation of clock error is an upper bound, which although potentially
120 * looser than the feedback clock equivalent, is much more reliable. The status
121 * is determined by the userland daemon.
123 struct ffclock_info {
124 struct bintime error;
125 struct bintime tick_time;
126 struct bintime tick_time_lerp;
128 uint64_t period_lerp;
129 int leapsec_adjustment;
134 * Snapshot of system clocks and related information. Holds time read from each
135 * clock based on a single read of the active hardware timecounter, as well as
136 * respective clock information such as error estimates and the ffcounter value
137 * at the time of the read.
139 struct sysclock_snap {
140 struct fbclock_info fb_info;
141 struct ffclock_info ff_info;
147 /* Take a snapshot of the system clocks and related information. */
148 void sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast);
150 /* Convert a timestamp from the selected system clock into bintime. */
151 int sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt,
152 int whichclock, uint32_t flags);
154 /* Resets feed-forward clock from RTC */
155 void ffclock_reset_clock(struct timespec *ts);
158 * Return the current value of the feed-forward clock counter. Essential to
159 * measure time interval in counter units. If a fast timecounter is used by the
160 * system, may also allow fast but accurate timestamping.
162 void ffclock_read_counter(ffcounter *ffcount);
165 * Retrieve feed-forward counter value and time of last kernel tick. This
166 * accepts the FFCLOCK_LERP flag.
168 void ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags);
171 * Low level routines to convert a counter timestamp into absolute time and a
172 * counter timestamp interval into an interval in seconds. The absolute time
173 * conversion accepts the FFCLOCK_LERP flag.
175 void ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags);
176 void ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt);
179 * Feed-forward clock routines.
181 * These functions rely on the timecounters and ffclock_estimates stored in
182 * fftimehands. Note that the error_bound parameter is not the error of the
183 * clock but an upper bound on the error of the absolute time or time interval
186 * ffclock_abstime(): retrieves current time as counter value and convert this
187 * timestamp in seconds. The value (in seconds) of the converted timestamp
188 * depends on the flags passed: for a given counter value, different
189 * conversions are possible. Different clock models can be selected by
190 * combining flags (for example (FFCLOCK_LERP|FFCLOCK_UPTIME) produces
191 * linearly interpolated uptime).
192 * ffclock_difftime(): computes a time interval in seconds based on an interval
193 * measured in ffcounter units. This should be the preferred way to measure
194 * small time intervals very accurately.
196 void ffclock_abstime(ffcounter *ffcount, struct bintime *bt,
197 struct bintime *error_bound, uint32_t flags);
198 void ffclock_difftime(ffcounter ffdelta, struct bintime *bt,
199 struct bintime *error_bound);
202 * Wrapper routines to return current absolute time using the feed-forward
203 * clock. These functions are named after those defined in <sys/time.h>, which
204 * contains a description of the original ones.
206 void ffclock_bintime(struct bintime *bt);
207 void ffclock_nanotime(struct timespec *tsp);
208 void ffclock_microtime(struct timeval *tvp);
210 void ffclock_getbintime(struct bintime *bt);
211 void ffclock_getnanotime(struct timespec *tsp);
212 void ffclock_getmicrotime(struct timeval *tvp);
214 void ffclock_binuptime(struct bintime *bt);
215 void ffclock_nanouptime(struct timespec *tsp);
216 void ffclock_microuptime(struct timeval *tvp);
218 void ffclock_getbinuptime(struct bintime *bt);
219 void ffclock_getnanouptime(struct timespec *tsp);
220 void ffclock_getmicrouptime(struct timeval *tvp);
223 * Wrapper routines to convert a time interval specified in ffcounter units into
224 * seconds using the current feed-forward clock estimates.
226 void ffclock_bindifftime(ffcounter ffdelta, struct bintime *bt);
227 void ffclock_nanodifftime(ffcounter ffdelta, struct timespec *tsp);
228 void ffclock_microdifftime(ffcounter ffdelta, struct timeval *tvp);
231 * When FFCLOCK is enabled in the kernel, [get]{bin,nano,micro}[up]time() become
232 * wrappers around equivalent feedback or feed-forward functions. Provide access
233 * outside of kern_tc.c to the feedback clock equivalent functions for
234 * specialised use i.e. these are not for general consumption.
236 void fbclock_bintime(struct bintime *bt);
237 void fbclock_nanotime(struct timespec *tsp);
238 void fbclock_microtime(struct timeval *tvp);
240 void fbclock_getbintime(struct bintime *bt);
241 void fbclock_getnanotime(struct timespec *tsp);
242 void fbclock_getmicrotime(struct timeval *tvp);
244 void fbclock_binuptime(struct bintime *bt);
245 void fbclock_nanouptime(struct timespec *tsp);
246 void fbclock_microuptime(struct timeval *tvp);
248 void fbclock_getbinuptime(struct bintime *bt);
249 void fbclock_getnanouptime(struct timespec *tsp);
250 void fbclock_getmicrouptime(struct timeval *tvp);
253 * Public system clock wrapper API which allows consumers to select which clock
254 * to obtain time from, independent of the current default system clock. These
255 * wrappers should be used instead of directly calling the underlying fbclock_
256 * or ffclock_ functions.
259 bintime_fromclock(struct bintime *bt, int whichclock)
262 if (whichclock == SYSCLOCK_FFWD)
269 nanotime_fromclock(struct timespec *tsp, int whichclock)
272 if (whichclock == SYSCLOCK_FFWD)
273 ffclock_nanotime(tsp);
275 fbclock_nanotime(tsp);
279 microtime_fromclock(struct timeval *tvp, int whichclock)
282 if (whichclock == SYSCLOCK_FFWD)
283 ffclock_microtime(tvp);
285 fbclock_microtime(tvp);
289 getbintime_fromclock(struct bintime *bt, int whichclock)
292 if (whichclock == SYSCLOCK_FFWD)
293 ffclock_getbintime(bt);
295 fbclock_getbintime(bt);
299 getnanotime_fromclock(struct timespec *tsp, int whichclock)
302 if (whichclock == SYSCLOCK_FFWD)
303 ffclock_getnanotime(tsp);
305 fbclock_getnanotime(tsp);
309 getmicrotime_fromclock(struct timeval *tvp, int whichclock)
312 if (whichclock == SYSCLOCK_FFWD)
313 ffclock_getmicrotime(tvp);
315 fbclock_getmicrotime(tvp);
319 binuptime_fromclock(struct bintime *bt, int whichclock)
322 if (whichclock == SYSCLOCK_FFWD)
323 ffclock_binuptime(bt);
325 fbclock_binuptime(bt);
329 nanouptime_fromclock(struct timespec *tsp, int whichclock)
332 if (whichclock == SYSCLOCK_FFWD)
333 ffclock_nanouptime(tsp);
335 fbclock_nanouptime(tsp);
339 microuptime_fromclock(struct timeval *tvp, int whichclock)
342 if (whichclock == SYSCLOCK_FFWD)
343 ffclock_microuptime(tvp);
345 fbclock_microuptime(tvp);
349 getbinuptime_fromclock(struct bintime *bt, int whichclock)
352 if (whichclock == SYSCLOCK_FFWD)
353 ffclock_getbinuptime(bt);
355 fbclock_getbinuptime(bt);
359 getnanouptime_fromclock(struct timespec *tsp, int whichclock)
362 if (whichclock == SYSCLOCK_FFWD)
363 ffclock_getnanouptime(tsp);
365 fbclock_getnanouptime(tsp);
369 getmicrouptime_fromclock(struct timeval *tvp, int whichclock)
372 if (whichclock == SYSCLOCK_FFWD)
373 ffclock_getmicrouptime(tvp);
375 fbclock_getmicrouptime(tvp);
380 /* Feed-Forward Clock system calls. */
382 int ffclock_getcounter(ffcounter *ffcount);
383 int ffclock_getestimate(struct ffclock_estimate *cest);
384 int ffclock_setestimate(struct ffclock_estimate *cest);
388 #endif /* __BSD_VISIBLE */
389 #endif /* _SYS_TIMEFF_H_ */