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Commit | Line | Data |
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fc235a3f ML |
1 | /* |
2 | chronyd/chronyc - Programs for keeping computer clocks accurate. | |
3 | ||
4 | ********************************************************************** | |
33967780 | 5 | * Copyright (C) Miroslav Lichvar 2014-2015 |
fc235a3f ML |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of version 2 of the GNU General Public License as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but | |
12 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License along | |
17 | * with this program; if not, write to the Free Software Foundation, Inc., | |
18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
19 | * | |
20 | ********************************************************************** | |
21 | ||
22 | ======================================================================= | |
23 | ||
24 | Generic driver functions to complete system-specific drivers | |
25 | */ | |
26 | ||
27 | #include "config.h" | |
28 | ||
29 | #include "sysincl.h" | |
30 | ||
31 | #include "sys_generic.h" | |
32 | ||
9cf78b97 | 33 | #include "conf.h" |
fc235a3f ML |
34 | #include "local.h" |
35 | #include "localp.h" | |
36 | #include "logging.h" | |
400820d3 | 37 | #include "privops.h" |
fc235a3f ML |
38 | #include "sched.h" |
39 | #include "util.h" | |
40 | ||
41 | /* ================================================== */ | |
42 | ||
02cbe5e1 | 43 | /* System clock drivers */ |
fc235a3f ML |
44 | static lcl_ReadFrequencyDriver drv_read_freq; |
45 | static lcl_SetFrequencyDriver drv_set_freq; | |
02cbe5e1 | 46 | static lcl_SetSyncStatusDriver drv_set_sync_status; |
d6fdae5f ML |
47 | static lcl_AccrueOffsetDriver drv_accrue_offset; |
48 | static lcl_OffsetCorrectionDriver drv_get_offset_correction; | |
fc235a3f ML |
49 | |
50 | /* Current frequency as requested by the local module (in ppm) */ | |
51 | static double base_freq; | |
52 | ||
53 | /* Maximum frequency that can be set by drv_set_freq (in ppm) */ | |
54 | static double max_freq; | |
55 | ||
56 | /* Maximum expected delay in the actual frequency change (e.g. kernel ticks) | |
57 | in local time */ | |
58 | static double max_freq_change_delay; | |
59 | ||
9cf78b97 ML |
60 | /* Maximum allowed frequency offset relative to the base frequency */ |
61 | static double max_corr_freq; | |
62 | ||
fc235a3f ML |
63 | /* Amount of outstanding offset to process */ |
64 | static double offset_register; | |
65 | ||
66 | /* Minimum offset to correct */ | |
67 | #define MIN_OFFSET_CORRECTION 1.0e-9 | |
68 | ||
69 | /* Current frequency offset between base_freq and the real clock frequency | |
70 | as set by drv_set_freq (not in ppm) */ | |
71 | static double slew_freq; | |
72 | ||
fc235a3f | 73 | /* Time (raw) of last update of slewing frequency and offset */ |
d0dfa1de | 74 | static struct timespec slew_start; |
fc235a3f | 75 | |
af8e4a51 ML |
76 | /* Limits for the slew length */ |
77 | #define MIN_SLEW_DURATION 1.0 | |
78 | #define MAX_SLEW_DURATION 1.0e4 | |
fc235a3f | 79 | |
0076458e | 80 | /* Scheduler timeout ID for ending of the currently running slew */ |
fc235a3f | 81 | static SCH_TimeoutID slew_timeout_id; |
fc235a3f ML |
82 | |
83 | /* Suggested offset correction rate (correction time * offset) */ | |
84 | static double correction_rate; | |
85 | ||
86 | /* Maximum expected offset correction error caused by delayed change in the | |
87 | real frequency of the clock */ | |
88 | static double slew_error; | |
89 | ||
d6fdae5f ML |
90 | /* Minimum offset that the system driver can slew faster than the maximum |
91 | frequency offset that it allows to be set directly */ | |
92 | static double fastslew_min_offset; | |
93 | ||
94 | /* Maximum slew rate of the system driver */ | |
95 | static double fastslew_max_rate; | |
96 | ||
97 | /* Flag indicating that the system driver is currently slewing */ | |
98 | static int fastslew_active; | |
99 | ||
fc235a3f ML |
100 | /* ================================================== */ |
101 | ||
102 | static void handle_end_of_slew(void *anything); | |
a33a9551 | 103 | static void update_slew(void); |
fc235a3f ML |
104 | |
105 | /* ================================================== */ | |
106 | /* Adjust slew_start on clock step */ | |
107 | ||
108 | static void | |
d0dfa1de | 109 | handle_step(struct timespec *raw, struct timespec *cooked, double dfreq, |
44c9744d | 110 | double doffset, LCL_ChangeType change_type, void *anything) |
fc235a3f | 111 | { |
9cc609c4 | 112 | if (change_type == LCL_ChangeStep) { |
d0dfa1de | 113 | UTI_AddDoubleToTimespec(&slew_start, -doffset, &slew_start); |
a33a9551 | 114 | } |
fc235a3f ML |
115 | } |
116 | ||
ad942e35 ML |
117 | /* ================================================== */ |
118 | ||
d6fdae5f ML |
119 | static void |
120 | start_fastslew(void) | |
121 | { | |
122 | if (!drv_accrue_offset) | |
123 | return; | |
124 | ||
125 | drv_accrue_offset(offset_register, 0.0); | |
126 | ||
f282856c | 127 | DEBUG_LOG("fastslew offset=%e", offset_register); |
d6fdae5f ML |
128 | |
129 | offset_register = 0.0; | |
130 | fastslew_active = 1; | |
131 | } | |
132 | ||
133 | /* ================================================== */ | |
134 | ||
135 | static void | |
d0dfa1de | 136 | stop_fastslew(struct timespec *now) |
d6fdae5f ML |
137 | { |
138 | double corr; | |
139 | ||
140 | if (!drv_get_offset_correction || !fastslew_active) | |
141 | return; | |
142 | ||
143 | /* Cancel the remaining offset */ | |
144 | drv_get_offset_correction(now, &corr, NULL); | |
145 | drv_accrue_offset(corr, 0.0); | |
146 | offset_register -= corr; | |
147 | } | |
148 | ||
149 | /* ================================================== */ | |
150 | ||
ad942e35 ML |
151 | static double |
152 | clamp_freq(double freq) | |
153 | { | |
154 | if (freq > max_freq) | |
155 | return max_freq; | |
156 | if (freq < -max_freq) | |
157 | return -max_freq; | |
158 | return freq; | |
159 | } | |
160 | ||
fc235a3f ML |
161 | /* ================================================== */ |
162 | /* End currently running slew and start a new one */ | |
163 | ||
164 | static void | |
165 | update_slew(void) | |
166 | { | |
d0dfa1de | 167 | struct timespec now, end_of_slew; |
fc235a3f ML |
168 | double old_slew_freq, total_freq, corr_freq, duration; |
169 | ||
170 | /* Remove currently running timeout */ | |
0076458e | 171 | SCH_RemoveTimeout(slew_timeout_id); |
fc235a3f ML |
172 | |
173 | LCL_ReadRawTime(&now); | |
174 | ||
175 | /* Adjust the offset register by achieved slew */ | |
cfe706f0 | 176 | duration = UTI_DiffTimespecsToDouble(&now, &slew_start); |
fc235a3f ML |
177 | offset_register -= slew_freq * duration; |
178 | ||
d6fdae5f ML |
179 | stop_fastslew(&now); |
180 | ||
fc235a3f ML |
181 | /* Estimate how long should the next slew take */ |
182 | if (fabs(offset_register) < MIN_OFFSET_CORRECTION) { | |
af8e4a51 | 183 | duration = MAX_SLEW_DURATION; |
fc235a3f ML |
184 | } else { |
185 | duration = correction_rate / fabs(offset_register); | |
af8e4a51 ML |
186 | if (duration < MIN_SLEW_DURATION) |
187 | duration = MIN_SLEW_DURATION; | |
fc235a3f ML |
188 | } |
189 | ||
190 | /* Get frequency offset needed to slew the offset in the duration | |
191 | and clamp it to the allowed maximum */ | |
192 | corr_freq = offset_register / duration; | |
9cf78b97 ML |
193 | if (corr_freq < -max_corr_freq) |
194 | corr_freq = -max_corr_freq; | |
195 | else if (corr_freq > max_corr_freq) | |
196 | corr_freq = max_corr_freq; | |
fc235a3f | 197 | |
d6fdae5f ML |
198 | /* Let the system driver perform the slew if the requested frequency |
199 | offset is too large for the frequency driver */ | |
200 | if (drv_accrue_offset && fabs(corr_freq) >= fastslew_max_rate && | |
201 | fabs(offset_register) > fastslew_min_offset) { | |
202 | start_fastslew(); | |
203 | corr_freq = 0.0; | |
204 | } | |
205 | ||
fc235a3f | 206 | /* Get the new real frequency and clamp it */ |
ad942e35 | 207 | total_freq = clamp_freq(base_freq + corr_freq * (1.0e6 - base_freq)); |
fc235a3f ML |
208 | |
209 | /* Set the new frequency (the actual frequency returned by the call may be | |
210 | slightly different from the requested frequency due to rounding) */ | |
211 | total_freq = (*drv_set_freq)(total_freq); | |
212 | ||
213 | /* Compute the new slewing frequency, it's relative to the real frequency to | |
214 | make the calculation in offset_convert() cheaper */ | |
215 | old_slew_freq = slew_freq; | |
216 | slew_freq = (total_freq - base_freq) / (1.0e6 - total_freq); | |
217 | ||
218 | /* Compute the dispersion introduced by changing frequency and add it | |
219 | to all statistics held at higher levels in the system */ | |
220 | slew_error = fabs((old_slew_freq - slew_freq) * max_freq_change_delay); | |
e8bb95ba ML |
221 | if (slew_error >= MIN_OFFSET_CORRECTION) |
222 | lcl_InvokeDispersionNotifyHandlers(slew_error); | |
fc235a3f ML |
223 | |
224 | /* Compute the duration of the slew and clamp it. If the slewing frequency | |
225 | is zero or has wrong sign (e.g. due to rounding in the frequency driver or | |
d6fdae5f ML |
226 | when base_freq is larger than max_freq, or fast slew is active), use the |
227 | maximum timeout and try again on the next update. */ | |
f88a712d ML |
228 | if (fabs(offset_register) < MIN_OFFSET_CORRECTION || |
229 | offset_register * slew_freq <= 0.0) { | |
af8e4a51 | 230 | duration = MAX_SLEW_DURATION; |
fc235a3f ML |
231 | } else { |
232 | duration = offset_register / slew_freq; | |
af8e4a51 ML |
233 | if (duration < MIN_SLEW_DURATION) |
234 | duration = MIN_SLEW_DURATION; | |
235 | else if (duration > MAX_SLEW_DURATION) | |
236 | duration = MAX_SLEW_DURATION; | |
fc235a3f ML |
237 | } |
238 | ||
239 | /* Restart timer for the next update */ | |
d0dfa1de | 240 | UTI_AddDoubleToTimespec(&now, duration, &end_of_slew); |
fc235a3f | 241 | slew_timeout_id = SCH_AddTimeout(&end_of_slew, handle_end_of_slew, NULL); |
fc235a3f | 242 | slew_start = now; |
fc235a3f | 243 | |
f282856c | 244 | DEBUG_LOG("slew offset=%e corr_rate=%e base_freq=%f total_freq=%f slew_freq=%e duration=%f slew_error=%e", |
e8bb95ba ML |
245 | offset_register, correction_rate, base_freq, total_freq, slew_freq, |
246 | duration, slew_error); | |
fc235a3f ML |
247 | } |
248 | ||
249 | /* ================================================== */ | |
250 | ||
251 | static void | |
252 | handle_end_of_slew(void *anything) | |
253 | { | |
0076458e | 254 | slew_timeout_id = 0; |
fc235a3f ML |
255 | update_slew(); |
256 | } | |
257 | ||
258 | /* ================================================== */ | |
259 | ||
260 | static double | |
261 | read_frequency(void) | |
262 | { | |
263 | return base_freq; | |
264 | } | |
265 | ||
266 | /* ================================================== */ | |
267 | ||
268 | static double | |
269 | set_frequency(double freq_ppm) | |
270 | { | |
271 | base_freq = freq_ppm; | |
272 | update_slew(); | |
273 | ||
274 | return base_freq; | |
275 | } | |
276 | ||
277 | /* ================================================== */ | |
278 | ||
279 | static void | |
280 | accrue_offset(double offset, double corr_rate) | |
281 | { | |
282 | offset_register += offset; | |
283 | correction_rate = corr_rate; | |
284 | ||
285 | update_slew(); | |
286 | } | |
287 | ||
288 | /* ================================================== */ | |
289 | /* Determine the correction to generate the cooked time for given raw time */ | |
290 | ||
291 | static void | |
d0dfa1de | 292 | offset_convert(struct timespec *raw, |
fc235a3f ML |
293 | double *corr, double *err) |
294 | { | |
d6fdae5f | 295 | double duration, fastslew_corr, fastslew_err; |
fc235a3f | 296 | |
cfe706f0 | 297 | duration = UTI_DiffTimespecsToDouble(raw, &slew_start); |
fc235a3f | 298 | |
d6fdae5f ML |
299 | if (drv_get_offset_correction && fastslew_active) { |
300 | drv_get_offset_correction(raw, &fastslew_corr, &fastslew_err); | |
301 | if (fastslew_corr == 0.0 && fastslew_err == 0.0) | |
302 | fastslew_active = 0; | |
303 | } else { | |
304 | fastslew_corr = fastslew_err = 0.0; | |
305 | } | |
306 | ||
307 | *corr = slew_freq * duration + fastslew_corr - offset_register; | |
308 | ||
309 | if (err) { | |
310 | *err = fastslew_err; | |
311 | if (fabs(duration) <= max_freq_change_delay) | |
312 | *err += slew_error; | |
313 | } | |
fc235a3f ML |
314 | } |
315 | ||
cf3c7b3b ML |
316 | /* ================================================== */ |
317 | /* Positive means currently fast of true time, i.e. jump backwards */ | |
318 | ||
f6a9c5c1 | 319 | static int |
cf3c7b3b ML |
320 | apply_step_offset(double offset) |
321 | { | |
d0dfa1de ML |
322 | struct timespec old_time, new_time; |
323 | struct timeval new_time_tv; | |
cf3c7b3b ML |
324 | double err; |
325 | ||
326 | LCL_ReadRawTime(&old_time); | |
d0dfa1de ML |
327 | UTI_AddDoubleToTimespec(&old_time, -offset, &new_time); |
328 | UTI_TimespecToTimeval(&new_time, &new_time_tv); | |
cf3c7b3b | 329 | |
d0dfa1de | 330 | if (PRV_SetTime(&new_time_tv, NULL) < 0) { |
f282856c | 331 | DEBUG_LOG("settimeofday() failed"); |
f6a9c5c1 | 332 | return 0; |
cf3c7b3b ML |
333 | } |
334 | ||
335 | LCL_ReadRawTime(&old_time); | |
cfe706f0 | 336 | err = UTI_DiffTimespecsToDouble(&old_time, &new_time); |
cf3c7b3b ML |
337 | |
338 | lcl_InvokeDispersionNotifyHandlers(fabs(err)); | |
f6a9c5c1 ML |
339 | |
340 | return 1; | |
cf3c7b3b ML |
341 | } |
342 | ||
fc235a3f ML |
343 | /* ================================================== */ |
344 | ||
02cbe5e1 ML |
345 | static void |
346 | set_sync_status(int synchronised, double est_error, double max_error) | |
347 | { | |
348 | double offset; | |
349 | ||
350 | offset = fabs(offset_register); | |
351 | if (est_error < offset) | |
352 | est_error = offset; | |
353 | max_error += offset; | |
354 | ||
355 | if (drv_set_sync_status) | |
356 | drv_set_sync_status(synchronised, est_error, max_error); | |
357 | } | |
358 | ||
359 | /* ================================================== */ | |
360 | ||
fc235a3f ML |
361 | void |
362 | SYS_Generic_CompleteFreqDriver(double max_set_freq_ppm, double max_set_freq_delay, | |
363 | lcl_ReadFrequencyDriver sys_read_freq, | |
364 | lcl_SetFrequencyDriver sys_set_freq, | |
365 | lcl_ApplyStepOffsetDriver sys_apply_step_offset, | |
d6fdae5f ML |
366 | double min_fastslew_offset, double max_fastslew_rate, |
367 | lcl_AccrueOffsetDriver sys_accrue_offset, | |
368 | lcl_OffsetCorrectionDriver sys_get_offset_correction, | |
e14a03a1 ML |
369 | lcl_SetLeapDriver sys_set_leap, |
370 | lcl_SetSyncStatusDriver sys_set_sync_status) | |
fc235a3f ML |
371 | { |
372 | max_freq = max_set_freq_ppm; | |
373 | max_freq_change_delay = max_set_freq_delay * (1.0 + max_freq / 1.0e6); | |
374 | drv_read_freq = sys_read_freq; | |
375 | drv_set_freq = sys_set_freq; | |
d6fdae5f ML |
376 | drv_accrue_offset = sys_accrue_offset; |
377 | drv_get_offset_correction = sys_get_offset_correction; | |
02cbe5e1 | 378 | drv_set_sync_status = sys_set_sync_status; |
fc235a3f ML |
379 | |
380 | base_freq = (*drv_read_freq)(); | |
381 | slew_freq = 0.0; | |
382 | offset_register = 0.0; | |
383 | ||
9cf78b97 ML |
384 | max_corr_freq = CNF_GetMaxSlewRate() / 1.0e6; |
385 | ||
d6fdae5f ML |
386 | fastslew_min_offset = min_fastslew_offset; |
387 | fastslew_max_rate = max_fastslew_rate / 1.0e6; | |
388 | fastslew_active = 0; | |
389 | ||
fc235a3f | 390 | lcl_RegisterSystemDrivers(read_frequency, set_frequency, |
cf3c7b3b ML |
391 | accrue_offset, sys_apply_step_offset ? |
392 | sys_apply_step_offset : apply_step_offset, | |
02cbe5e1 | 393 | offset_convert, sys_set_leap, set_sync_status); |
fc235a3f ML |
394 | |
395 | LCL_AddParameterChangeHandler(handle_step, NULL); | |
396 | } | |
397 | ||
398 | /* ================================================== */ | |
399 | ||
400 | void | |
401 | SYS_Generic_Finalise(void) | |
402 | { | |
d0dfa1de | 403 | struct timespec now; |
d6fdae5f | 404 | |
fc235a3f ML |
405 | /* Must *NOT* leave a slew running - clock could drift way off |
406 | if the daemon is not restarted */ | |
0076458e ML |
407 | |
408 | SCH_RemoveTimeout(slew_timeout_id); | |
409 | slew_timeout_id = 0; | |
fc235a3f | 410 | |
ad942e35 | 411 | (*drv_set_freq)(clamp_freq(base_freq)); |
d6fdae5f ML |
412 | |
413 | LCL_ReadRawTime(&now); | |
414 | stop_fastslew(&now); | |
5f6f265f ML |
415 | |
416 | LCL_RemoveParameterChangeHandler(handle_step, NULL); | |
fc235a3f ML |
417 | } |
418 | ||
419 | /* ================================================== */ |