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1 | /***************************************************************************** |
2 | * * | |
3 | * Copyright (c) David L. Mills 1993 * | |
4 | * * | |
5 | * Permission to use, copy, modify, and distribute this software and its * | |
6 | * documentation for any purpose and without fee is hereby granted, provided * | |
7 | * that the above copyright notice appears in all copies and that both the * | |
8 | * copyright notice and this permission notice appear in supporting * | |
9 | * documentation, and that the name University of Delaware not be used in * | |
10 | * advertising or publicity pertaining to distribution of the software * | |
11 | * without specific, written prior permission. The University of Delaware * | |
12 | * makes no representations about the suitability this software for any * | |
13 | * purpose. It is provided "as is" without express or implied warranty. * | |
14 | * * | |
15 | *****************************************************************************/ | |
16 | ||
17 | /* | |
18 | * Modification history timex.h | |
19 | * | |
20 | * 29 Dec 97 Russell King | |
21 | * Moved CLOCK_TICK_RATE, CLOCK_TICK_FACTOR and FINETUNE to asm/timex.h | |
22 | * for ARM machines | |
23 | * | |
24 | * 9 Jan 97 Adrian Sun | |
25 | * Shifted LATCH define to allow access to alpha machines. | |
26 | * | |
27 | * 26 Sep 94 David L. Mills | |
28 | * Added defines for hybrid phase/frequency-lock loop. | |
29 | * | |
30 | * 19 Mar 94 David L. Mills | |
31 | * Moved defines from kernel routines to header file and added new | |
32 | * defines for PPS phase-lock loop. | |
33 | * | |
34 | * 20 Feb 94 David L. Mills | |
35 | * Revised status codes and structures for external clock and PPS | |
36 | * signal discipline. | |
37 | * | |
38 | * 28 Nov 93 David L. Mills | |
39 | * Adjusted parameters to improve stability and increase poll | |
40 | * interval. | |
41 | * | |
42 | * 17 Sep 93 David L. Mills | |
43 | * Created file $NTP/include/sys/timex.h | |
44 | * 07 Oct 93 Torsten Duwe | |
45 | * Derived linux/timex.h | |
46 | * 1995-08-13 Torsten Duwe | |
47 | * kernel PLL updated to 1994-12-13 specs (rfc-1589) | |
48 | * 1997-08-30 Ulrich Windl | |
49 | * Added new constant NTP_PHASE_LIMIT | |
50 | * 2004-08-12 Christoph Lameter | |
51 | * Reworked time interpolation logic | |
52 | */ | |
53 | #ifndef _LINUX_TIMEX_H | |
54 | #define _LINUX_TIMEX_H | |
55 | ||
56 | #include <linux/config.h> | |
57 | #include <linux/compiler.h> | |
58 | #include <linux/time.h> | |
59 | ||
60 | #include <asm/param.h> | |
61 | #include <asm/timex.h> | |
62 | ||
63 | /* | |
64 | * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen | |
65 | * for a slightly underdamped convergence characteristic. SHIFT_KH | |
66 | * establishes the damping of the FLL and is chosen by wisdom and black | |
67 | * art. | |
68 | * | |
69 | * MAXTC establishes the maximum time constant of the PLL. With the | |
70 | * SHIFT_KG and SHIFT_KF values given and a time constant range from | |
71 | * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, | |
72 | * respectively. | |
73 | */ | |
74 | #define SHIFT_KG 6 /* phase factor (shift) */ | |
75 | #define SHIFT_KF 16 /* PLL frequency factor (shift) */ | |
76 | #define SHIFT_KH 2 /* FLL frequency factor (shift) */ | |
77 | #define MAXTC 6 /* maximum time constant (shift) */ | |
78 | ||
79 | /* | |
80 | * The SHIFT_SCALE define establishes the decimal point of the time_phase | |
81 | * variable which serves as an extension to the low-order bits of the | |
82 | * system clock variable. The SHIFT_UPDATE define establishes the decimal | |
83 | * point of the time_offset variable which represents the current offset | |
84 | * with respect to standard time. The FINENSEC define represents 1 nsec in | |
85 | * scaled units. | |
86 | * | |
87 | * SHIFT_USEC defines the scaling (shift) of the time_freq and | |
88 | * time_tolerance variables, which represent the current frequency | |
89 | * offset and maximum frequency tolerance. | |
90 | * | |
91 | * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable. | |
92 | */ | |
93 | #define SHIFT_SCALE 22 /* phase scale (shift) */ | |
94 | #define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */ | |
95 | #define SHIFT_USEC 16 /* frequency offset scale (shift) */ | |
96 | #define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */ | |
97 | ||
98 | #define MAXPHASE 512000L /* max phase error (us) */ | |
99 | #define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ | |
100 | #define MAXTIME (200L << PPS_AVG) /* max PPS error (jitter) (200 us) */ | |
101 | #define MINSEC 16L /* min interval between updates (s) */ | |
102 | #define MAXSEC 1200L /* max interval between updates (s) */ | |
103 | #define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ | |
104 | ||
105 | /* | |
106 | * The following defines are used only if a pulse-per-second (PPS) | |
107 | * signal is available and connected via a modem control lead, such as | |
108 | * produced by the optional ppsclock feature incorporated in the Sun | |
109 | * asynch driver. They establish the design parameters of the frequency- | |
110 | * lock loop used to discipline the CPU clock oscillator to the PPS | |
111 | * signal. | |
112 | * | |
113 | * PPS_AVG is the averaging factor for the frequency loop, as well as | |
114 | * the time and frequency dispersion. | |
115 | * | |
116 | * PPS_SHIFT and PPS_SHIFTMAX specify the minimum and maximum | |
117 | * calibration intervals, respectively, in seconds as a power of two. | |
118 | * | |
119 | * PPS_VALID is the maximum interval before the PPS signal is considered | |
120 | * invalid and protocol updates used directly instead. | |
121 | * | |
122 | * MAXGLITCH is the maximum interval before a time offset of more than | |
123 | * MAXTIME is believed. | |
124 | */ | |
125 | #define PPS_AVG 2 /* pps averaging constant (shift) */ | |
126 | #define PPS_SHIFT 2 /* min interval duration (s) (shift) */ | |
127 | #define PPS_SHIFTMAX 8 /* max interval duration (s) (shift) */ | |
128 | #define PPS_VALID 120 /* pps signal watchdog max (s) */ | |
129 | #define MAXGLITCH 30 /* pps signal glitch max (s) */ | |
130 | ||
131 | /* | |
132 | * syscall interface - used (mainly by NTP daemon) | |
133 | * to discipline kernel clock oscillator | |
134 | */ | |
135 | struct timex { | |
136 | unsigned int modes; /* mode selector */ | |
137 | long offset; /* time offset (usec) */ | |
138 | long freq; /* frequency offset (scaled ppm) */ | |
139 | long maxerror; /* maximum error (usec) */ | |
140 | long esterror; /* estimated error (usec) */ | |
141 | int status; /* clock command/status */ | |
142 | long constant; /* pll time constant */ | |
143 | long precision; /* clock precision (usec) (read only) */ | |
144 | long tolerance; /* clock frequency tolerance (ppm) | |
145 | * (read only) | |
146 | */ | |
147 | struct timeval time; /* (read only) */ | |
148 | long tick; /* (modified) usecs between clock ticks */ | |
149 | ||
150 | long ppsfreq; /* pps frequency (scaled ppm) (ro) */ | |
151 | long jitter; /* pps jitter (us) (ro) */ | |
152 | int shift; /* interval duration (s) (shift) (ro) */ | |
153 | long stabil; /* pps stability (scaled ppm) (ro) */ | |
154 | long jitcnt; /* jitter limit exceeded (ro) */ | |
155 | long calcnt; /* calibration intervals (ro) */ | |
156 | long errcnt; /* calibration errors (ro) */ | |
157 | long stbcnt; /* stability limit exceeded (ro) */ | |
158 | ||
159 | int :32; int :32; int :32; int :32; | |
160 | int :32; int :32; int :32; int :32; | |
161 | int :32; int :32; int :32; int :32; | |
162 | }; | |
163 | ||
164 | /* | |
165 | * Mode codes (timex.mode) | |
166 | */ | |
167 | #define ADJ_OFFSET 0x0001 /* time offset */ | |
168 | #define ADJ_FREQUENCY 0x0002 /* frequency offset */ | |
169 | #define ADJ_MAXERROR 0x0004 /* maximum time error */ | |
170 | #define ADJ_ESTERROR 0x0008 /* estimated time error */ | |
171 | #define ADJ_STATUS 0x0010 /* clock status */ | |
172 | #define ADJ_TIMECONST 0x0020 /* pll time constant */ | |
173 | #define ADJ_TICK 0x4000 /* tick value */ | |
174 | #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ | |
175 | ||
176 | /* xntp 3.4 compatibility names */ | |
177 | #define MOD_OFFSET ADJ_OFFSET | |
178 | #define MOD_FREQUENCY ADJ_FREQUENCY | |
179 | #define MOD_MAXERROR ADJ_MAXERROR | |
180 | #define MOD_ESTERROR ADJ_ESTERROR | |
181 | #define MOD_STATUS ADJ_STATUS | |
182 | #define MOD_TIMECONST ADJ_TIMECONST | |
183 | #define MOD_CLKB ADJ_TICK | |
184 | #define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */ | |
185 | ||
186 | ||
187 | /* | |
188 | * Status codes (timex.status) | |
189 | */ | |
190 | #define STA_PLL 0x0001 /* enable PLL updates (rw) */ | |
191 | #define STA_PPSFREQ 0x0002 /* enable PPS freq discipline (rw) */ | |
192 | #define STA_PPSTIME 0x0004 /* enable PPS time discipline (rw) */ | |
193 | #define STA_FLL 0x0008 /* select frequency-lock mode (rw) */ | |
194 | ||
195 | #define STA_INS 0x0010 /* insert leap (rw) */ | |
196 | #define STA_DEL 0x0020 /* delete leap (rw) */ | |
197 | #define STA_UNSYNC 0x0040 /* clock unsynchronized (rw) */ | |
198 | #define STA_FREQHOLD 0x0080 /* hold frequency (rw) */ | |
199 | ||
200 | #define STA_PPSSIGNAL 0x0100 /* PPS signal present (ro) */ | |
201 | #define STA_PPSJITTER 0x0200 /* PPS signal jitter exceeded (ro) */ | |
202 | #define STA_PPSWANDER 0x0400 /* PPS signal wander exceeded (ro) */ | |
203 | #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ | |
204 | ||
205 | #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ | |
206 | ||
207 | #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ | |
208 | STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ | |
209 | ||
210 | /* | |
211 | * Clock states (time_state) | |
212 | */ | |
213 | #define TIME_OK 0 /* clock synchronized, no leap second */ | |
214 | #define TIME_INS 1 /* insert leap second */ | |
215 | #define TIME_DEL 2 /* delete leap second */ | |
216 | #define TIME_OOP 3 /* leap second in progress */ | |
217 | #define TIME_WAIT 4 /* leap second has occurred */ | |
218 | #define TIME_ERROR 5 /* clock not synchronized */ | |
219 | #define TIME_BAD TIME_ERROR /* bw compat */ | |
220 | ||
221 | #ifdef __KERNEL__ | |
222 | /* | |
223 | * kernel variables | |
224 | * Note: maximum error = NTP synch distance = dispersion + delay / 2; | |
225 | * estimated error = NTP dispersion. | |
226 | */ | |
227 | extern unsigned long tick_usec; /* USER_HZ period (usec) */ | |
228 | extern unsigned long tick_nsec; /* ACTHZ period (nsec) */ | |
229 | extern int tickadj; /* amount of adjustment per tick */ | |
230 | ||
231 | /* | |
232 | * phase-lock loop variables | |
233 | */ | |
234 | extern int time_state; /* clock status */ | |
235 | extern int time_status; /* clock synchronization status bits */ | |
236 | extern long time_offset; /* time adjustment (us) */ | |
237 | extern long time_constant; /* pll time constant */ | |
238 | extern long time_tolerance; /* frequency tolerance (ppm) */ | |
239 | extern long time_precision; /* clock precision (us) */ | |
240 | extern long time_maxerror; /* maximum error */ | |
241 | extern long time_esterror; /* estimated error */ | |
242 | ||
243 | extern long time_freq; /* frequency offset (scaled ppm) */ | |
244 | extern long time_reftime; /* time at last adjustment (s) */ | |
245 | ||
246 | extern long time_adjust; /* The amount of adjtime left */ | |
247 | extern long time_next_adjust; /* Value for time_adjust at next tick */ | |
248 | ||
249 | /* interface variables pps->timer interrupt */ | |
250 | extern long pps_offset; /* pps time offset (us) */ | |
251 | extern long pps_jitter; /* time dispersion (jitter) (us) */ | |
252 | extern long pps_freq; /* frequency offset (scaled ppm) */ | |
253 | extern long pps_stabil; /* frequency dispersion (scaled ppm) */ | |
254 | extern long pps_valid; /* pps signal watchdog counter */ | |
255 | ||
256 | /* interface variables pps->adjtimex */ | |
257 | extern int pps_shift; /* interval duration (s) (shift) */ | |
258 | extern long pps_jitcnt; /* jitter limit exceeded */ | |
259 | extern long pps_calcnt; /* calibration intervals */ | |
260 | extern long pps_errcnt; /* calibration errors */ | |
261 | extern long pps_stbcnt; /* stability limit exceeded */ | |
262 | ||
263 | #ifdef CONFIG_TIME_INTERPOLATION | |
264 | ||
265 | #define TIME_SOURCE_CPU 0 | |
266 | #define TIME_SOURCE_MMIO64 1 | |
267 | #define TIME_SOURCE_MMIO32 2 | |
268 | #define TIME_SOURCE_FUNCTION 3 | |
269 | ||
270 | /* For proper operations time_interpolator clocks must run slightly slower | |
271 | * than the standard clock since the interpolator may only correct by having | |
272 | * time jump forward during a tick. A slower clock is usually a side effect | |
273 | * of the integer divide of the nanoseconds in a second by the frequency. | |
274 | * The accuracy of the division can be increased by specifying a shift. | |
275 | * However, this may cause the clock not to be slow enough. | |
276 | * The interpolator will self-tune the clock by slowing down if no | |
277 | * resets occur or speeding up if the time jumps per analysis cycle | |
278 | * become too high. | |
279 | * | |
280 | * Setting jitter compensates for a fluctuating timesource by comparing | |
281 | * to the last value read from the timesource to insure that an earlier value | |
282 | * is not returned by a later call. The price to pay | |
283 | * for the compensation is that the timer routines are not as scalable anymore. | |
284 | */ | |
285 | ||
286 | struct time_interpolator { | |
287 | u16 source; /* time source flags */ | |
288 | u8 shift; /* increases accuracy of multiply by shifting. */ | |
289 | /* Note that bits may be lost if shift is set too high */ | |
290 | u8 jitter; /* if set compensate for fluctuations */ | |
291 | u32 nsec_per_cyc; /* set by register_time_interpolator() */ | |
292 | void *addr; /* address of counter or function */ | |
293 | u64 mask; /* mask the valid bits of the counter */ | |
294 | unsigned long offset; /* nsec offset at last update of interpolator */ | |
295 | u64 last_counter; /* counter value in units of the counter at last update */ | |
296 | u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */ | |
297 | u64 frequency; /* frequency in counts/second */ | |
298 | long drift; /* drift in parts-per-million (or -1) */ | |
299 | unsigned long skips; /* skips forward */ | |
300 | unsigned long ns_skipped; /* nanoseconds skipped */ | |
301 | struct time_interpolator *next; | |
302 | }; | |
303 | ||
304 | extern void register_time_interpolator(struct time_interpolator *); | |
305 | extern void unregister_time_interpolator(struct time_interpolator *); | |
306 | extern void time_interpolator_reset(void); | |
307 | extern unsigned long time_interpolator_get_offset(void); | |
308 | ||
309 | #else /* !CONFIG_TIME_INTERPOLATION */ | |
310 | ||
311 | static inline void | |
312 | time_interpolator_reset(void) | |
313 | { | |
314 | } | |
315 | ||
316 | #endif /* !CONFIG_TIME_INTERPOLATION */ | |
317 | ||
318 | #endif /* KERNEL */ | |
319 | ||
320 | #endif /* LINUX_TIMEX_H */ |