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}). */
59 * Index into the sysclocks array for obtaining the ASCII name of a particular
62 #define SYSCLOCK_FBCK 0
63 #define SYSCLOCK_FFWD 1
64 extern int sysclock_active;
67 * Parameters of counter characterisation required by feed-forward algorithms.
69 #define FFCLOCK_SKM_SCALE 1024
72 * Feed-forward clock status
74 #define FFCLOCK_STA_UNSYNC 1
75 #define FFCLOCK_STA_WARMUP 2
78 * Clock flags to select how the feed-forward counter is converted to absolute
79 * time by ffclock_convert_abs().
80 * FAST: do not read the hardware counter, return feed-forward clock time
81 * at last tick. The time returned has the resolution of the kernel
83 * LERP: linear interpolation of ffclock time to guarantee monotonic time.
84 * LEAPSEC: include leap seconds.
85 * UPTIME: removes time of boot.
87 #define FFCLOCK_FAST 1
88 #define FFCLOCK_LERP 2
89 #define FFCLOCK_LEAPSEC 4
90 #define FFCLOCK_UPTIME 8
92 /* Resets feed-forward clock from RTC */
93 void ffclock_reset_clock(struct timespec *ts);
96 * Return the current value of the feed-forward clock counter. Essential to
97 * measure time interval in counter units. If a fast timecounter is used by the
98 * system, may also allow fast but accurate timestamping.
100 void ffclock_read_counter(ffcounter *ffcount);
103 * Retrieve feed-forward counter value and time of last kernel tick. This
104 * accepts the FFCLOCK_LERP flag.
106 void ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags);
109 * Low level routines to convert a counter timestamp into absolute time and a
110 * counter timestamp interval into an interval in seconds. The absolute time
111 * conversion accepts the FFCLOCK_LERP flag.
113 void ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags);
114 void ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt);
117 * Feed-forward clock routines.
119 * These functions rely on the timecounters and ffclock_estimates stored in
120 * fftimehands. Note that the error_bound parameter is not the error of the
121 * clock but an upper bound on the error of the absolute time or time interval
124 * ffclock_abstime(): retrieves current time as counter value and convert this
125 * timestamp in seconds. The value (in seconds) of the converted timestamp
126 * depends on the flags passed: for a given counter value, different
127 * conversions are possible. Different clock models can be selected by
128 * combining flags (for example (FFCLOCK_LERP|FFCLOCK_UPTIME) produces
129 * linearly interpolated uptime).
130 * ffclock_difftime(): computes a time interval in seconds based on an interval
131 * measured in ffcounter units. This should be the preferred way to measure
132 * small time intervals very accurately.
134 void ffclock_abstime(ffcounter *ffcount, struct bintime *bt,
135 struct bintime *error_bound, uint32_t flags);
136 void ffclock_difftime(ffcounter ffdelta, struct bintime *bt,
137 struct bintime *error_bound);
140 * Wrapper routines to return current absolute time using the feed-forward
141 * clock. These functions are named after those defined in <sys/time.h>, which
142 * contains a description of the original ones.
144 void ffclock_bintime(struct bintime *bt);
145 void ffclock_nanotime(struct timespec *tsp);
146 void ffclock_microtime(struct timeval *tvp);
148 void ffclock_getbintime(struct bintime *bt);
149 void ffclock_getnanotime(struct timespec *tsp);
150 void ffclock_getmicrotime(struct timeval *tvp);
152 void ffclock_binuptime(struct bintime *bt);
153 void ffclock_nanouptime(struct timespec *tsp);
154 void ffclock_microuptime(struct timeval *tvp);
156 void ffclock_getbinuptime(struct bintime *bt);
157 void ffclock_getnanouptime(struct timespec *tsp);
158 void ffclock_getmicrouptime(struct timeval *tvp);
161 * Wrapper routines to convert a time interval specified in ffcounter units into
162 * seconds using the current feed-forward clock estimates.
164 void ffclock_bindifftime(ffcounter ffdelta, struct bintime *bt);
165 void ffclock_nanodifftime(ffcounter ffdelta, struct timespec *tsp);
166 void ffclock_microdifftime(ffcounter ffdelta, struct timeval *tvp);
169 * When FFCLOCK is enabled in the kernel, [get]{bin,nano,micro}[up]time() become
170 * wrappers around equivalent feedback or feed-forward functions. Provide access
171 * outside of kern_tc.c to the feedback clock equivalent functions for
172 * specialised use i.e. these are not for general consumption.
174 void fbclock_bintime(struct bintime *bt);
175 void fbclock_nanotime(struct timespec *tsp);
176 void fbclock_microtime(struct timeval *tvp);
178 void fbclock_getbintime(struct bintime *bt);
179 void fbclock_getnanotime(struct timespec *tsp);
180 void fbclock_getmicrotime(struct timeval *tvp);
182 void fbclock_binuptime(struct bintime *bt);
183 void fbclock_nanouptime(struct timespec *tsp);
184 void fbclock_microuptime(struct timeval *tvp);
186 void fbclock_getbinuptime(struct bintime *bt);
187 void fbclock_getnanouptime(struct timespec *tsp);
188 void fbclock_getmicrouptime(struct timeval *tvp);
191 * Public system clock wrapper API which allows consumers to select which clock
192 * to obtain time from, independent of the current default system clock. These
193 * wrappers should be used instead of directly calling the underlying fbclock_
194 * or ffclock_ functions.
197 bintime_fromclock(struct bintime *bt, int whichclock)
200 if (whichclock == SYSCLOCK_FFWD)
207 nanotime_fromclock(struct timespec *tsp, int whichclock)
210 if (whichclock == SYSCLOCK_FFWD)
211 ffclock_nanotime(tsp);
213 fbclock_nanotime(tsp);
217 microtime_fromclock(struct timeval *tvp, int whichclock)
220 if (whichclock == SYSCLOCK_FFWD)
221 ffclock_microtime(tvp);
223 fbclock_microtime(tvp);
227 getbintime_fromclock(struct bintime *bt, int whichclock)
230 if (whichclock == SYSCLOCK_FFWD)
231 ffclock_getbintime(bt);
233 fbclock_getbintime(bt);
237 getnanotime_fromclock(struct timespec *tsp, int whichclock)
240 if (whichclock == SYSCLOCK_FFWD)
241 ffclock_getnanotime(tsp);
243 fbclock_getnanotime(tsp);
247 getmicrotime_fromclock(struct timeval *tvp, int whichclock)
250 if (whichclock == SYSCLOCK_FFWD)
251 ffclock_getmicrotime(tvp);
253 fbclock_getmicrotime(tvp);
257 binuptime_fromclock(struct bintime *bt, int whichclock)
260 if (whichclock == SYSCLOCK_FFWD)
261 ffclock_binuptime(bt);
263 fbclock_binuptime(bt);
267 nanouptime_fromclock(struct timespec *tsp, int whichclock)
270 if (whichclock == SYSCLOCK_FFWD)
271 ffclock_nanouptime(tsp);
273 fbclock_nanouptime(tsp);
277 microuptime_fromclock(struct timeval *tvp, int whichclock)
280 if (whichclock == SYSCLOCK_FFWD)
281 ffclock_microuptime(tvp);
283 fbclock_microuptime(tvp);
287 getbinuptime_fromclock(struct bintime *bt, int whichclock)
290 if (whichclock == SYSCLOCK_FFWD)
291 ffclock_getbinuptime(bt);
293 fbclock_getbinuptime(bt);
297 getnanouptime_fromclock(struct timespec *tsp, int whichclock)
300 if (whichclock == SYSCLOCK_FFWD)
301 ffclock_getnanouptime(tsp);
303 fbclock_getnanouptime(tsp);
307 getmicrouptime_fromclock(struct timeval *tvp, int whichclock)
310 if (whichclock == SYSCLOCK_FFWD)
311 ffclock_getmicrouptime(tvp);
313 fbclock_getmicrouptime(tvp);
318 /* Feed-Forward Clock system calls. */
320 int ffclock_getcounter(ffcounter *ffcount);
321 int ffclock_getestimate(struct ffclock_estimate *cest);
322 int ffclock_setestimate(struct ffclock_estimate *cest);
326 #endif /* __BSD_VISIBLE */
327 #endif /* _SYS_TIMEFF_H_ */