john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 1 | /* |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 2 | * NTP state machine interfaces and logic. |
| 3 | * |
| 4 | * This code was mainly moved from kernel/timer.c and kernel/time.c |
| 5 | * Please see those files for relevant copyright info and historical |
| 6 | * changelogs. |
| 7 | */ |
Alexey Dobriyan | aa0ac36 | 2007-07-15 23:40:39 -0700 | [diff] [blame] | 8 | #include <linux/capability.h> |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 9 | #include <linux/clocksource.h> |
Maciej W. Rozycki | eb3f938 | 2008-09-22 14:42:40 -0700 | [diff] [blame] | 10 | #include <linux/workqueue.h> |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 11 | #include <linux/hrtimer.h> |
| 12 | #include <linux/jiffies.h> |
| 13 | #include <linux/math64.h> |
| 14 | #include <linux/timex.h> |
| 15 | #include <linux/time.h> |
| 16 | #include <linux/mm.h> |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 17 | #include <linux/module.h> |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 18 | |
Roman Zippel | b0ee755 | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 19 | /* |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 20 | * NTP timekeeping variables: |
Roman Zippel | b0ee755 | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 21 | */ |
Roman Zippel | b0ee755 | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 22 | |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 23 | /* USER_HZ period (usecs): */ |
| 24 | unsigned long tick_usec = TICK_USEC; |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 25 | |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 26 | /* ACTHZ period (nsecs): */ |
| 27 | unsigned long tick_nsec; |
| 28 | |
| 29 | u64 tick_length; |
| 30 | static u64 tick_length_base; |
| 31 | |
| 32 | static struct hrtimer leap_timer; |
| 33 | |
Ingo Molnar | bbd1267 | 2009-02-22 12:11:11 +0100 | [diff] [blame] | 34 | #define MAX_TICKADJ 500LL /* usecs */ |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 35 | #define MAX_TICKADJ_SCALED \ |
Ingo Molnar | bbd1267 | 2009-02-22 12:11:11 +0100 | [diff] [blame] | 36 | (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ) |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 37 | |
| 38 | /* |
| 39 | * phase-lock loop variables |
| 40 | */ |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 41 | |
| 42 | /* |
| 43 | * clock synchronization status |
| 44 | * |
| 45 | * (TIME_ERROR prevents overwriting the CMOS clock) |
| 46 | */ |
| 47 | static int time_state = TIME_OK; |
| 48 | |
| 49 | /* clock status bits: */ |
| 50 | int time_status = STA_UNSYNC; |
| 51 | |
| 52 | /* TAI offset (secs): */ |
| 53 | static long time_tai; |
| 54 | |
| 55 | /* time adjustment (nsecs): */ |
| 56 | static s64 time_offset; |
| 57 | |
| 58 | /* pll time constant: */ |
| 59 | static long time_constant = 2; |
| 60 | |
| 61 | /* maximum error (usecs): */ |
john stultz | 1f5b8f8 | 2010-01-28 15:02:41 -0800 | [diff] [blame] | 62 | static long time_maxerror = NTP_PHASE_LIMIT; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 63 | |
| 64 | /* estimated error (usecs): */ |
john stultz | 1f5b8f8 | 2010-01-28 15:02:41 -0800 | [diff] [blame] | 65 | static long time_esterror = NTP_PHASE_LIMIT; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 66 | |
| 67 | /* frequency offset (scaled nsecs/secs): */ |
| 68 | static s64 time_freq; |
| 69 | |
| 70 | /* time at last adjustment (secs): */ |
| 71 | static long time_reftime; |
| 72 | |
John Stultz | e1292ba | 2010-03-18 20:19:27 -0700 | [diff] [blame] | 73 | static long time_adjust; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 74 | |
Ingo Molnar | 069569e | 2009-02-22 16:03:37 +0100 | [diff] [blame] | 75 | /* constant (boot-param configurable) NTP tick adjustment (upscaled) */ |
| 76 | static s64 ntp_tick_adj; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 77 | |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 78 | #ifdef CONFIG_NTP_PPS |
| 79 | |
| 80 | /* |
| 81 | * The following variables are used when a pulse-per-second (PPS) signal |
| 82 | * is available. They establish the engineering parameters of the clock |
| 83 | * discipline loop when controlled by the PPS signal. |
| 84 | */ |
| 85 | #define PPS_VALID 10 /* PPS signal watchdog max (s) */ |
| 86 | #define PPS_POPCORN 4 /* popcorn spike threshold (shift) */ |
| 87 | #define PPS_INTMIN 2 /* min freq interval (s) (shift) */ |
| 88 | #define PPS_INTMAX 8 /* max freq interval (s) (shift) */ |
| 89 | #define PPS_INTCOUNT 4 /* number of consecutive good intervals to |
| 90 | increase pps_shift or consecutive bad |
| 91 | intervals to decrease it */ |
| 92 | #define PPS_MAXWANDER 100000 /* max PPS freq wander (ns/s) */ |
| 93 | |
| 94 | static int pps_valid; /* signal watchdog counter */ |
| 95 | static long pps_tf[3]; /* phase median filter */ |
| 96 | static long pps_jitter; /* current jitter (ns) */ |
| 97 | static struct timespec pps_fbase; /* beginning of the last freq interval */ |
| 98 | static int pps_shift; /* current interval duration (s) (shift) */ |
| 99 | static int pps_intcnt; /* interval counter */ |
| 100 | static s64 pps_freq; /* frequency offset (scaled ns/s) */ |
| 101 | static long pps_stabil; /* current stability (scaled ns/s) */ |
| 102 | |
| 103 | /* |
| 104 | * PPS signal quality monitors |
| 105 | */ |
| 106 | static long pps_calcnt; /* calibration intervals */ |
| 107 | static long pps_jitcnt; /* jitter limit exceeded */ |
| 108 | static long pps_stbcnt; /* stability limit exceeded */ |
| 109 | static long pps_errcnt; /* calibration errors */ |
| 110 | |
| 111 | |
| 112 | /* PPS kernel consumer compensates the whole phase error immediately. |
| 113 | * Otherwise, reduce the offset by a fixed factor times the time constant. |
| 114 | */ |
| 115 | static inline s64 ntp_offset_chunk(s64 offset) |
| 116 | { |
| 117 | if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) |
| 118 | return offset; |
| 119 | else |
| 120 | return shift_right(offset, SHIFT_PLL + time_constant); |
| 121 | } |
| 122 | |
| 123 | static inline void pps_reset_freq_interval(void) |
| 124 | { |
| 125 | /* the PPS calibration interval may end |
| 126 | surprisingly early */ |
| 127 | pps_shift = PPS_INTMIN; |
| 128 | pps_intcnt = 0; |
| 129 | } |
| 130 | |
| 131 | /** |
| 132 | * pps_clear - Clears the PPS state variables |
| 133 | * |
| 134 | * Must be called while holding a write on the xtime_lock |
| 135 | */ |
| 136 | static inline void pps_clear(void) |
| 137 | { |
| 138 | pps_reset_freq_interval(); |
| 139 | pps_tf[0] = 0; |
| 140 | pps_tf[1] = 0; |
| 141 | pps_tf[2] = 0; |
| 142 | pps_fbase.tv_sec = pps_fbase.tv_nsec = 0; |
| 143 | pps_freq = 0; |
| 144 | } |
| 145 | |
| 146 | /* Decrease pps_valid to indicate that another second has passed since |
| 147 | * the last PPS signal. When it reaches 0, indicate that PPS signal is |
| 148 | * missing. |
| 149 | * |
| 150 | * Must be called while holding a write on the xtime_lock |
| 151 | */ |
| 152 | static inline void pps_dec_valid(void) |
| 153 | { |
| 154 | if (pps_valid > 0) |
| 155 | pps_valid--; |
| 156 | else { |
| 157 | time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | |
| 158 | STA_PPSWANDER | STA_PPSERROR); |
| 159 | pps_clear(); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | static inline void pps_set_freq(s64 freq) |
| 164 | { |
| 165 | pps_freq = freq; |
| 166 | } |
| 167 | |
| 168 | static inline int is_error_status(int status) |
| 169 | { |
| 170 | return (time_status & (STA_UNSYNC|STA_CLOCKERR)) |
| 171 | /* PPS signal lost when either PPS time or |
| 172 | * PPS frequency synchronization requested |
| 173 | */ |
| 174 | || ((time_status & (STA_PPSFREQ|STA_PPSTIME)) |
| 175 | && !(time_status & STA_PPSSIGNAL)) |
| 176 | /* PPS jitter exceeded when |
| 177 | * PPS time synchronization requested */ |
| 178 | || ((time_status & (STA_PPSTIME|STA_PPSJITTER)) |
| 179 | == (STA_PPSTIME|STA_PPSJITTER)) |
| 180 | /* PPS wander exceeded or calibration error when |
| 181 | * PPS frequency synchronization requested |
| 182 | */ |
| 183 | || ((time_status & STA_PPSFREQ) |
| 184 | && (time_status & (STA_PPSWANDER|STA_PPSERROR))); |
| 185 | } |
| 186 | |
| 187 | static inline void pps_fill_timex(struct timex *txc) |
| 188 | { |
| 189 | txc->ppsfreq = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) * |
| 190 | PPM_SCALE_INV, NTP_SCALE_SHIFT); |
| 191 | txc->jitter = pps_jitter; |
| 192 | if (!(time_status & STA_NANO)) |
| 193 | txc->jitter /= NSEC_PER_USEC; |
| 194 | txc->shift = pps_shift; |
| 195 | txc->stabil = pps_stabil; |
| 196 | txc->jitcnt = pps_jitcnt; |
| 197 | txc->calcnt = pps_calcnt; |
| 198 | txc->errcnt = pps_errcnt; |
| 199 | txc->stbcnt = pps_stbcnt; |
| 200 | } |
| 201 | |
| 202 | #else /* !CONFIG_NTP_PPS */ |
| 203 | |
| 204 | static inline s64 ntp_offset_chunk(s64 offset) |
| 205 | { |
| 206 | return shift_right(offset, SHIFT_PLL + time_constant); |
| 207 | } |
| 208 | |
| 209 | static inline void pps_reset_freq_interval(void) {} |
| 210 | static inline void pps_clear(void) {} |
| 211 | static inline void pps_dec_valid(void) {} |
| 212 | static inline void pps_set_freq(s64 freq) {} |
| 213 | |
| 214 | static inline int is_error_status(int status) |
| 215 | { |
| 216 | return status & (STA_UNSYNC|STA_CLOCKERR); |
| 217 | } |
| 218 | |
| 219 | static inline void pps_fill_timex(struct timex *txc) |
| 220 | { |
| 221 | /* PPS is not implemented, so these are zero */ |
| 222 | txc->ppsfreq = 0; |
| 223 | txc->jitter = 0; |
| 224 | txc->shift = 0; |
| 225 | txc->stabil = 0; |
| 226 | txc->jitcnt = 0; |
| 227 | txc->calcnt = 0; |
| 228 | txc->errcnt = 0; |
| 229 | txc->stbcnt = 0; |
| 230 | } |
| 231 | |
| 232 | #endif /* CONFIG_NTP_PPS */ |
| 233 | |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 234 | /* |
| 235 | * NTP methods: |
| 236 | */ |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 237 | |
Ingo Molnar | 9ce616a | 2009-02-22 12:42:59 +0100 | [diff] [blame] | 238 | /* |
| 239 | * Update (tick_length, tick_length_base, tick_nsec), based |
| 240 | * on (tick_usec, ntp_tick_adj, time_freq): |
| 241 | */ |
Adrian Bunk | 70bc42f | 2006-09-30 23:28:29 -0700 | [diff] [blame] | 242 | static void ntp_update_frequency(void) |
| 243 | { |
Ingo Molnar | 9ce616a | 2009-02-22 12:42:59 +0100 | [diff] [blame] | 244 | u64 second_length; |
Ingo Molnar | bc26c31 | 2009-02-22 12:17:36 +0100 | [diff] [blame] | 245 | u64 new_base; |
Adrian Bunk | 70bc42f | 2006-09-30 23:28:29 -0700 | [diff] [blame] | 246 | |
Ingo Molnar | 9ce616a | 2009-02-22 12:42:59 +0100 | [diff] [blame] | 247 | second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) |
| 248 | << NTP_SCALE_SHIFT; |
| 249 | |
Ingo Molnar | 069569e | 2009-02-22 16:03:37 +0100 | [diff] [blame] | 250 | second_length += ntp_tick_adj; |
Ingo Molnar | 9ce616a | 2009-02-22 12:42:59 +0100 | [diff] [blame] | 251 | second_length += time_freq; |
| 252 | |
Ingo Molnar | 9ce616a | 2009-02-22 12:42:59 +0100 | [diff] [blame] | 253 | tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT; |
Ingo Molnar | bc26c31 | 2009-02-22 12:17:36 +0100 | [diff] [blame] | 254 | new_base = div_u64(second_length, NTP_INTERVAL_FREQ); |
john stultz | fdcedf7 | 2009-02-18 16:02:22 -0800 | [diff] [blame] | 255 | |
| 256 | /* |
| 257 | * Don't wait for the next second_overflow, apply |
Ingo Molnar | bc26c31 | 2009-02-22 12:17:36 +0100 | [diff] [blame] | 258 | * the change to the tick length immediately: |
john stultz | fdcedf7 | 2009-02-18 16:02:22 -0800 | [diff] [blame] | 259 | */ |
Ingo Molnar | bc26c31 | 2009-02-22 12:17:36 +0100 | [diff] [blame] | 260 | tick_length += new_base - tick_length_base; |
| 261 | tick_length_base = new_base; |
Adrian Bunk | 70bc42f | 2006-09-30 23:28:29 -0700 | [diff] [blame] | 262 | } |
| 263 | |
Ingo Molnar | 478b7aa | 2009-02-22 13:22:23 +0100 | [diff] [blame] | 264 | static inline s64 ntp_update_offset_fll(s64 offset64, long secs) |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 265 | { |
| 266 | time_status &= ~STA_MODE; |
| 267 | |
| 268 | if (secs < MINSEC) |
Ingo Molnar | 478b7aa | 2009-02-22 13:22:23 +0100 | [diff] [blame] | 269 | return 0; |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 270 | |
| 271 | if (!(time_status & STA_FLL) && (secs <= MAXSEC)) |
Ingo Molnar | 478b7aa | 2009-02-22 13:22:23 +0100 | [diff] [blame] | 272 | return 0; |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 273 | |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 274 | time_status |= STA_MODE; |
| 275 | |
Ingo Molnar | 478b7aa | 2009-02-22 13:22:23 +0100 | [diff] [blame] | 276 | return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs); |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 277 | } |
| 278 | |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 279 | static void ntp_update_offset(long offset) |
| 280 | { |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 281 | s64 freq_adj; |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 282 | s64 offset64; |
| 283 | long secs; |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 284 | |
| 285 | if (!(time_status & STA_PLL)) |
| 286 | return; |
| 287 | |
Roman Zippel | eea83d8 | 2008-05-01 04:34:33 -0700 | [diff] [blame] | 288 | if (!(time_status & STA_NANO)) |
Roman Zippel | 9f14f66 | 2008-05-01 04:34:36 -0700 | [diff] [blame] | 289 | offset *= NSEC_PER_USEC; |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 290 | |
| 291 | /* |
| 292 | * Scale the phase adjustment and |
| 293 | * clamp to the operating range. |
| 294 | */ |
Roman Zippel | 9f14f66 | 2008-05-01 04:34:36 -0700 | [diff] [blame] | 295 | offset = min(offset, MAXPHASE); |
| 296 | offset = max(offset, -MAXPHASE); |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 297 | |
| 298 | /* |
| 299 | * Select how the frequency is to be controlled |
| 300 | * and in which mode (PLL or FLL). |
| 301 | */ |
John Stultz | 7e1b584 | 2010-01-28 20:20:44 -0800 | [diff] [blame] | 302 | secs = get_seconds() - time_reftime; |
Ingo Molnar | 10dd31a | 2009-02-22 13:38:40 +0100 | [diff] [blame] | 303 | if (unlikely(time_status & STA_FREQHOLD)) |
Ingo Molnar | c7986ac | 2009-02-22 13:29:09 +0100 | [diff] [blame] | 304 | secs = 0; |
| 305 | |
John Stultz | 7e1b584 | 2010-01-28 20:20:44 -0800 | [diff] [blame] | 306 | time_reftime = get_seconds(); |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 307 | |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 308 | offset64 = offset; |
Miroslav Lichvar | 8af3c15 | 2010-09-07 16:43:46 +0200 | [diff] [blame] | 309 | freq_adj = ntp_update_offset_fll(offset64, secs); |
Roman Zippel | 9f14f66 | 2008-05-01 04:34:36 -0700 | [diff] [blame] | 310 | |
Miroslav Lichvar | 8af3c15 | 2010-09-07 16:43:46 +0200 | [diff] [blame] | 311 | /* |
| 312 | * Clamp update interval to reduce PLL gain with low |
| 313 | * sampling rate (e.g. intermittent network connection) |
| 314 | * to avoid instability. |
| 315 | */ |
| 316 | if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant))) |
| 317 | secs = 1 << (SHIFT_PLL + 1 + time_constant); |
| 318 | |
| 319 | freq_adj += (offset64 * secs) << |
| 320 | (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant)); |
Ingo Molnar | f939890 | 2009-02-22 12:57:49 +0100 | [diff] [blame] | 321 | |
| 322 | freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED); |
| 323 | |
| 324 | time_freq = max(freq_adj, -MAXFREQ_SCALED); |
| 325 | |
| 326 | time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ); |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 327 | } |
| 328 | |
Roman Zippel | b0ee755 | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 329 | /** |
| 330 | * ntp_clear - Clears the NTP state variables |
| 331 | * |
| 332 | * Must be called while holding a write on the xtime_lock |
| 333 | */ |
| 334 | void ntp_clear(void) |
| 335 | { |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 336 | time_adjust = 0; /* stop active adjtime() */ |
| 337 | time_status |= STA_UNSYNC; |
| 338 | time_maxerror = NTP_PHASE_LIMIT; |
| 339 | time_esterror = NTP_PHASE_LIMIT; |
Roman Zippel | b0ee755 | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 340 | |
| 341 | ntp_update_frequency(); |
| 342 | |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 343 | tick_length = tick_length_base; |
| 344 | time_offset = 0; |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 345 | |
| 346 | /* Clear PPS state variables */ |
| 347 | pps_clear(); |
Roman Zippel | b0ee755 | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 348 | } |
| 349 | |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 350 | /* |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 351 | * Leap second processing. If in leap-insert state at the end of the |
| 352 | * day, the system clock is set back one second; if in leap-delete |
| 353 | * state, the system clock is set ahead one second. |
| 354 | */ |
| 355 | static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer) |
| 356 | { |
| 357 | enum hrtimer_restart res = HRTIMER_NORESTART; |
| 358 | |
Peter Zijlstra | ca10949 | 2008-11-25 12:43:51 +0100 | [diff] [blame] | 359 | write_seqlock(&xtime_lock); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 360 | |
| 361 | switch (time_state) { |
| 362 | case TIME_OK: |
| 363 | break; |
| 364 | case TIME_INS: |
John Stultz | 31089c1 | 2009-08-14 15:47:18 +0200 | [diff] [blame] | 365 | timekeeping_leap_insert(-1); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 366 | time_state = TIME_OOP; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 367 | printk(KERN_NOTICE |
| 368 | "Clock: inserting leap second 23:59:60 UTC\n"); |
Arjan van de Ven | cc584b2 | 2008-09-01 15:02:30 -0700 | [diff] [blame] | 369 | hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 370 | res = HRTIMER_RESTART; |
| 371 | break; |
| 372 | case TIME_DEL: |
John Stultz | 31089c1 | 2009-08-14 15:47:18 +0200 | [diff] [blame] | 373 | timekeeping_leap_insert(1); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 374 | time_tai--; |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 375 | time_state = TIME_WAIT; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 376 | printk(KERN_NOTICE |
| 377 | "Clock: deleting leap second 23:59:59 UTC\n"); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 378 | break; |
| 379 | case TIME_OOP: |
| 380 | time_tai++; |
| 381 | time_state = TIME_WAIT; |
| 382 | /* fall through */ |
| 383 | case TIME_WAIT: |
| 384 | if (!(time_status & (STA_INS | STA_DEL))) |
| 385 | time_state = TIME_OK; |
| 386 | break; |
| 387 | } |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 388 | |
Peter Zijlstra | ca10949 | 2008-11-25 12:43:51 +0100 | [diff] [blame] | 389 | write_sequnlock(&xtime_lock); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 390 | |
| 391 | return res; |
| 392 | } |
| 393 | |
| 394 | /* |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 395 | * this routine handles the overflow of the microsecond field |
| 396 | * |
| 397 | * The tricky bits of code to handle the accurate clock support |
| 398 | * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. |
| 399 | * They were originally developed for SUN and DEC kernels. |
| 400 | * All the kudos should go to Dave for this stuff. |
| 401 | */ |
| 402 | void second_overflow(void) |
| 403 | { |
Ingo Molnar | 39854fe | 2009-02-22 16:06:58 +0100 | [diff] [blame] | 404 | s64 delta; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 405 | |
| 406 | /* Bump the maxerror field */ |
Roman Zippel | 074b3b8 | 2008-05-01 04:34:34 -0700 | [diff] [blame] | 407 | time_maxerror += MAXFREQ / NSEC_PER_USEC; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 408 | if (time_maxerror > NTP_PHASE_LIMIT) { |
| 409 | time_maxerror = NTP_PHASE_LIMIT; |
| 410 | time_status |= STA_UNSYNC; |
| 411 | } |
| 412 | |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 413 | /* Compute the phase adjustment for the next second */ |
Ingo Molnar | 39854fe | 2009-02-22 16:06:58 +0100 | [diff] [blame] | 414 | tick_length = tick_length_base; |
| 415 | |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 416 | delta = ntp_offset_chunk(time_offset); |
Ingo Molnar | 39854fe | 2009-02-22 16:06:58 +0100 | [diff] [blame] | 417 | time_offset -= delta; |
| 418 | tick_length += delta; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 419 | |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 420 | /* Check PPS signal */ |
| 421 | pps_dec_valid(); |
| 422 | |
Ingo Molnar | 3c972c2 | 2009-02-22 12:06:57 +0100 | [diff] [blame] | 423 | if (!time_adjust) |
| 424 | return; |
| 425 | |
| 426 | if (time_adjust > MAX_TICKADJ) { |
| 427 | time_adjust -= MAX_TICKADJ; |
| 428 | tick_length += MAX_TICKADJ_SCALED; |
| 429 | return; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 430 | } |
Ingo Molnar | 3c972c2 | 2009-02-22 12:06:57 +0100 | [diff] [blame] | 431 | |
| 432 | if (time_adjust < -MAX_TICKADJ) { |
| 433 | time_adjust += MAX_TICKADJ; |
| 434 | tick_length -= MAX_TICKADJ_SCALED; |
| 435 | return; |
| 436 | } |
| 437 | |
| 438 | tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ) |
| 439 | << NTP_SCALE_SHIFT; |
| 440 | time_adjust = 0; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 441 | } |
| 442 | |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 443 | #ifdef CONFIG_GENERIC_CMOS_UPDATE |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 444 | |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 445 | /* Disable the cmos update - used by virtualization and embedded */ |
| 446 | int no_sync_cmos_clock __read_mostly; |
| 447 | |
Maciej W. Rozycki | eb3f938 | 2008-09-22 14:42:40 -0700 | [diff] [blame] | 448 | static void sync_cmos_clock(struct work_struct *work); |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 449 | |
Maciej W. Rozycki | eb3f938 | 2008-09-22 14:42:40 -0700 | [diff] [blame] | 450 | static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock); |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 451 | |
Maciej W. Rozycki | eb3f938 | 2008-09-22 14:42:40 -0700 | [diff] [blame] | 452 | static void sync_cmos_clock(struct work_struct *work) |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 453 | { |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 454 | struct timespec now, next; |
| 455 | int fail = 1; |
| 456 | |
| 457 | /* |
| 458 | * If we have an externally synchronized Linux clock, then update |
| 459 | * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be |
| 460 | * called as close as possible to 500 ms before the new second starts. |
| 461 | * This code is run on a timer. If the clock is set, that timer |
| 462 | * may not expire at the correct time. Thus, we adjust... |
| 463 | */ |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 464 | if (!ntp_synced()) { |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 465 | /* |
| 466 | * Not synced, exit, do not restart a timer (if one is |
| 467 | * running, let it run out). |
| 468 | */ |
| 469 | return; |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 470 | } |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 471 | |
| 472 | getnstimeofday(&now); |
David P. Reed | fa6a1a5 | 2007-11-14 17:49:21 -0500 | [diff] [blame] | 473 | if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 474 | fail = update_persistent_clock(now); |
| 475 | |
Maciej W. Rozycki | 4ff4b9e | 2008-09-05 14:05:31 -0700 | [diff] [blame] | 476 | next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2); |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 477 | if (next.tv_nsec <= 0) |
| 478 | next.tv_nsec += NSEC_PER_SEC; |
| 479 | |
| 480 | if (!fail) |
| 481 | next.tv_sec = 659; |
| 482 | else |
| 483 | next.tv_sec = 0; |
| 484 | |
| 485 | if (next.tv_nsec >= NSEC_PER_SEC) { |
| 486 | next.tv_sec++; |
| 487 | next.tv_nsec -= NSEC_PER_SEC; |
| 488 | } |
Maciej W. Rozycki | eb3f938 | 2008-09-22 14:42:40 -0700 | [diff] [blame] | 489 | schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next)); |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 490 | } |
| 491 | |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 492 | static void notify_cmos_timer(void) |
| 493 | { |
Tony Breeds | 298a5df | 2007-09-11 15:24:03 -0700 | [diff] [blame] | 494 | if (!no_sync_cmos_clock) |
Maciej W. Rozycki | eb3f938 | 2008-09-22 14:42:40 -0700 | [diff] [blame] | 495 | schedule_delayed_work(&sync_cmos_work, 0); |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 496 | } |
| 497 | |
| 498 | #else |
| 499 | static inline void notify_cmos_timer(void) { } |
| 500 | #endif |
| 501 | |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 502 | /* |
| 503 | * Start the leap seconds timer: |
| 504 | */ |
| 505 | static inline void ntp_start_leap_timer(struct timespec *ts) |
| 506 | { |
| 507 | long now = ts->tv_sec; |
| 508 | |
| 509 | if (time_status & STA_INS) { |
| 510 | time_state = TIME_INS; |
| 511 | now += 86400 - now % 86400; |
| 512 | hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS); |
| 513 | |
| 514 | return; |
| 515 | } |
| 516 | |
| 517 | if (time_status & STA_DEL) { |
| 518 | time_state = TIME_DEL; |
| 519 | now += 86400 - (now + 1) % 86400; |
| 520 | hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS); |
| 521 | } |
| 522 | } |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 523 | |
| 524 | /* |
| 525 | * Propagate a new txc->status value into the NTP state: |
| 526 | */ |
| 527 | static inline void process_adj_status(struct timex *txc, struct timespec *ts) |
| 528 | { |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 529 | if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) { |
| 530 | time_state = TIME_OK; |
| 531 | time_status = STA_UNSYNC; |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 532 | /* restart PPS frequency calibration */ |
| 533 | pps_reset_freq_interval(); |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 534 | } |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 535 | |
| 536 | /* |
| 537 | * If we turn on PLL adjustments then reset the |
| 538 | * reference time to current time. |
| 539 | */ |
| 540 | if (!(time_status & STA_PLL) && (txc->status & STA_PLL)) |
John Stultz | 7e1b584 | 2010-01-28 20:20:44 -0800 | [diff] [blame] | 541 | time_reftime = get_seconds(); |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 542 | |
John Stultz | a2a5ac8 | 2009-02-26 09:46:14 -0800 | [diff] [blame] | 543 | /* only set allowed bits */ |
| 544 | time_status &= STA_RONLY; |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 545 | time_status |= txc->status & ~STA_RONLY; |
| 546 | |
| 547 | switch (time_state) { |
| 548 | case TIME_OK: |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 549 | ntp_start_leap_timer(ts); |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 550 | break; |
| 551 | case TIME_INS: |
| 552 | case TIME_DEL: |
| 553 | time_state = TIME_OK; |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 554 | ntp_start_leap_timer(ts); |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 555 | case TIME_WAIT: |
| 556 | if (!(time_status & (STA_INS | STA_DEL))) |
| 557 | time_state = TIME_OK; |
| 558 | break; |
| 559 | case TIME_OOP: |
| 560 | hrtimer_restart(&leap_timer); |
| 561 | break; |
| 562 | } |
| 563 | } |
| 564 | /* |
| 565 | * Called with the xtime lock held, so we can access and modify |
| 566 | * all the global NTP state: |
| 567 | */ |
| 568 | static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts) |
| 569 | { |
| 570 | if (txc->modes & ADJ_STATUS) |
| 571 | process_adj_status(txc, ts); |
| 572 | |
| 573 | if (txc->modes & ADJ_NANO) |
| 574 | time_status |= STA_NANO; |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 575 | |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 576 | if (txc->modes & ADJ_MICRO) |
| 577 | time_status &= ~STA_NANO; |
| 578 | |
| 579 | if (txc->modes & ADJ_FREQUENCY) { |
Ingo Molnar | 2b9d149 | 2009-02-22 15:48:43 +0100 | [diff] [blame] | 580 | time_freq = txc->freq * PPM_SCALE; |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 581 | time_freq = min(time_freq, MAXFREQ_SCALED); |
| 582 | time_freq = max(time_freq, -MAXFREQ_SCALED); |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 583 | /* update pps_freq */ |
| 584 | pps_set_freq(time_freq); |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 585 | } |
| 586 | |
| 587 | if (txc->modes & ADJ_MAXERROR) |
| 588 | time_maxerror = txc->maxerror; |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 589 | |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 590 | if (txc->modes & ADJ_ESTERROR) |
| 591 | time_esterror = txc->esterror; |
| 592 | |
| 593 | if (txc->modes & ADJ_TIMECONST) { |
| 594 | time_constant = txc->constant; |
| 595 | if (!(time_status & STA_NANO)) |
| 596 | time_constant += 4; |
| 597 | time_constant = min(time_constant, (long)MAXTC); |
| 598 | time_constant = max(time_constant, 0l); |
| 599 | } |
| 600 | |
| 601 | if (txc->modes & ADJ_TAI && txc->constant > 0) |
| 602 | time_tai = txc->constant; |
| 603 | |
| 604 | if (txc->modes & ADJ_OFFSET) |
| 605 | ntp_update_offset(txc->offset); |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 606 | |
Ingo Molnar | 80f2257 | 2009-02-22 15:15:32 +0100 | [diff] [blame] | 607 | if (txc->modes & ADJ_TICK) |
| 608 | tick_usec = txc->tick; |
| 609 | |
| 610 | if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET)) |
| 611 | ntp_update_frequency(); |
| 612 | } |
| 613 | |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 614 | /* |
| 615 | * adjtimex mainly allows reading (and writing, if superuser) of |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 616 | * kernel time-keeping variables. used by xntpd. |
| 617 | */ |
| 618 | int do_adjtimex(struct timex *txc) |
| 619 | { |
Roman Zippel | eea83d8 | 2008-05-01 04:34:33 -0700 | [diff] [blame] | 620 | struct timespec ts; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 621 | int result; |
| 622 | |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 623 | /* Validate the data before disabling interrupts */ |
| 624 | if (txc->modes & ADJ_ADJTIME) { |
Roman Zippel | eea83d8 | 2008-05-01 04:34:33 -0700 | [diff] [blame] | 625 | /* singleshot must not be used with any other mode bits */ |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 626 | if (!(txc->modes & ADJ_OFFSET_SINGLESHOT)) |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 627 | return -EINVAL; |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 628 | if (!(txc->modes & ADJ_OFFSET_READONLY) && |
| 629 | !capable(CAP_SYS_TIME)) |
| 630 | return -EPERM; |
| 631 | } else { |
| 632 | /* In order to modify anything, you gotta be super-user! */ |
| 633 | if (txc->modes && !capable(CAP_SYS_TIME)) |
| 634 | return -EPERM; |
| 635 | |
Ingo Molnar | 53bbfa9 | 2008-02-20 07:58:42 +0100 | [diff] [blame] | 636 | /* |
| 637 | * if the quartz is off by more than 10% then |
| 638 | * something is VERY wrong! |
| 639 | */ |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 640 | if (txc->modes & ADJ_TICK && |
| 641 | (txc->tick < 900000/USER_HZ || |
| 642 | txc->tick > 1100000/USER_HZ)) |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 643 | return -EINVAL; |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 644 | |
| 645 | if (txc->modes & ADJ_STATUS && time_state != TIME_OK) |
| 646 | hrtimer_cancel(&leap_timer); |
John Stultz | 52bfb36 | 2007-11-26 20:42:19 +0100 | [diff] [blame] | 647 | } |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 648 | |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 649 | getnstimeofday(&ts); |
| 650 | |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 651 | write_seqlock_irq(&xtime_lock); |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 652 | |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 653 | if (txc->modes & ADJ_ADJTIME) { |
| 654 | long save_adjust = time_adjust; |
| 655 | |
| 656 | if (!(txc->modes & ADJ_OFFSET_READONLY)) { |
| 657 | /* adjtime() is independent from ntp_adjtime() */ |
| 658 | time_adjust = txc->offset; |
| 659 | ntp_update_frequency(); |
| 660 | } |
| 661 | txc->offset = save_adjust; |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 662 | } else { |
| 663 | |
| 664 | /* If there are input parameters, then process them: */ |
| 665 | if (txc->modes) |
| 666 | process_adjtimex_modes(txc, &ts); |
| 667 | |
| 668 | txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ, |
| 669 | NTP_SCALE_SHIFT); |
| 670 | if (!(time_status & STA_NANO)) |
| 671 | txc->offset /= NSEC_PER_USEC; |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 672 | } |
Roman Zippel | 916c7a8 | 2008-08-20 16:46:08 -0700 | [diff] [blame] | 673 | |
Roman Zippel | eea83d8 | 2008-05-01 04:34:33 -0700 | [diff] [blame] | 674 | result = time_state; /* mostly `TIME_OK' */ |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 675 | /* check for errors */ |
| 676 | if (is_error_status(time_status)) |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 677 | result = TIME_ERROR; |
| 678 | |
Roman Zippel | d40e944 | 2008-09-22 14:42:44 -0700 | [diff] [blame] | 679 | txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) * |
Ingo Molnar | 2b9d149 | 2009-02-22 15:48:43 +0100 | [diff] [blame] | 680 | PPM_SCALE_INV, NTP_SCALE_SHIFT); |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 681 | txc->maxerror = time_maxerror; |
| 682 | txc->esterror = time_esterror; |
| 683 | txc->status = time_status; |
| 684 | txc->constant = time_constant; |
Adrian Bunk | 70bc42f | 2006-09-30 23:28:29 -0700 | [diff] [blame] | 685 | txc->precision = 1; |
Roman Zippel | 074b3b8 | 2008-05-01 04:34:34 -0700 | [diff] [blame] | 686 | txc->tolerance = MAXFREQ_SCALED / PPM_SCALE; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 687 | txc->tick = tick_usec; |
Roman Zippel | 153b5d0 | 2008-05-01 04:34:37 -0700 | [diff] [blame] | 688 | txc->tai = time_tai; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 689 | |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 690 | /* fill PPS status fields */ |
| 691 | pps_fill_timex(txc); |
Ingo Molnar | e962916 | 2009-02-22 15:35:18 +0100 | [diff] [blame] | 692 | |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 693 | write_sequnlock_irq(&xtime_lock); |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 694 | |
Roman Zippel | eea83d8 | 2008-05-01 04:34:33 -0700 | [diff] [blame] | 695 | txc->time.tv_sec = ts.tv_sec; |
| 696 | txc->time.tv_usec = ts.tv_nsec; |
| 697 | if (!(time_status & STA_NANO)) |
| 698 | txc->time.tv_usec /= NSEC_PER_USEC; |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 699 | |
Thomas Gleixner | 8264445 | 2007-07-21 04:37:37 -0700 | [diff] [blame] | 700 | notify_cmos_timer(); |
Roman Zippel | ee9851b | 2008-05-01 04:34:32 -0700 | [diff] [blame] | 701 | |
| 702 | return result; |
john stultz | 4c7ee8d | 2006-09-30 23:28:22 -0700 | [diff] [blame] | 703 | } |
Roman Zippel | 10a398d | 2008-03-04 15:14:26 -0800 | [diff] [blame] | 704 | |
Alexander Gordeev | 025b40a | 2011-01-12 17:00:56 -0800 | [diff] [blame] | 705 | #ifdef CONFIG_NTP_PPS |
| 706 | |
| 707 | /* actually struct pps_normtime is good old struct timespec, but it is |
| 708 | * semantically different (and it is the reason why it was invented): |
| 709 | * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] |
| 710 | * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */ |
| 711 | struct pps_normtime { |
| 712 | __kernel_time_t sec; /* seconds */ |
| 713 | long nsec; /* nanoseconds */ |
| 714 | }; |
| 715 | |
| 716 | /* normalize the timestamp so that nsec is in the |
| 717 | ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */ |
| 718 | static inline struct pps_normtime pps_normalize_ts(struct timespec ts) |
| 719 | { |
| 720 | struct pps_normtime norm = { |
| 721 | .sec = ts.tv_sec, |
| 722 | .nsec = ts.tv_nsec |
| 723 | }; |
| 724 | |
| 725 | if (norm.nsec > (NSEC_PER_SEC >> 1)) { |
| 726 | norm.nsec -= NSEC_PER_SEC; |
| 727 | norm.sec++; |
| 728 | } |
| 729 | |
| 730 | return norm; |
| 731 | } |
| 732 | |
| 733 | /* get current phase correction and jitter */ |
| 734 | static inline long pps_phase_filter_get(long *jitter) |
| 735 | { |
| 736 | *jitter = pps_tf[0] - pps_tf[1]; |
| 737 | if (*jitter < 0) |
| 738 | *jitter = -*jitter; |
| 739 | |
| 740 | /* TODO: test various filters */ |
| 741 | return pps_tf[0]; |
| 742 | } |
| 743 | |
| 744 | /* add the sample to the phase filter */ |
| 745 | static inline void pps_phase_filter_add(long err) |
| 746 | { |
| 747 | pps_tf[2] = pps_tf[1]; |
| 748 | pps_tf[1] = pps_tf[0]; |
| 749 | pps_tf[0] = err; |
| 750 | } |
| 751 | |
| 752 | /* decrease frequency calibration interval length. |
| 753 | * It is halved after four consecutive unstable intervals. |
| 754 | */ |
| 755 | static inline void pps_dec_freq_interval(void) |
| 756 | { |
| 757 | if (--pps_intcnt <= -PPS_INTCOUNT) { |
| 758 | pps_intcnt = -PPS_INTCOUNT; |
| 759 | if (pps_shift > PPS_INTMIN) { |
| 760 | pps_shift--; |
| 761 | pps_intcnt = 0; |
| 762 | } |
| 763 | } |
| 764 | } |
| 765 | |
| 766 | /* increase frequency calibration interval length. |
| 767 | * It is doubled after four consecutive stable intervals. |
| 768 | */ |
| 769 | static inline void pps_inc_freq_interval(void) |
| 770 | { |
| 771 | if (++pps_intcnt >= PPS_INTCOUNT) { |
| 772 | pps_intcnt = PPS_INTCOUNT; |
| 773 | if (pps_shift < PPS_INTMAX) { |
| 774 | pps_shift++; |
| 775 | pps_intcnt = 0; |
| 776 | } |
| 777 | } |
| 778 | } |
| 779 | |
| 780 | /* update clock frequency based on MONOTONIC_RAW clock PPS signal |
| 781 | * timestamps |
| 782 | * |
| 783 | * At the end of the calibration interval the difference between the |
| 784 | * first and last MONOTONIC_RAW clock timestamps divided by the length |
| 785 | * of the interval becomes the frequency update. If the interval was |
| 786 | * too long, the data are discarded. |
| 787 | * Returns the difference between old and new frequency values. |
| 788 | */ |
| 789 | static long hardpps_update_freq(struct pps_normtime freq_norm) |
| 790 | { |
| 791 | long delta, delta_mod; |
| 792 | s64 ftemp; |
| 793 | |
| 794 | /* check if the frequency interval was too long */ |
| 795 | if (freq_norm.sec > (2 << pps_shift)) { |
| 796 | time_status |= STA_PPSERROR; |
| 797 | pps_errcnt++; |
| 798 | pps_dec_freq_interval(); |
| 799 | pr_err("hardpps: PPSERROR: interval too long - %ld s\n", |
| 800 | freq_norm.sec); |
| 801 | return 0; |
| 802 | } |
| 803 | |
| 804 | /* here the raw frequency offset and wander (stability) is |
| 805 | * calculated. If the wander is less than the wander threshold |
| 806 | * the interval is increased; otherwise it is decreased. |
| 807 | */ |
| 808 | ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT, |
| 809 | freq_norm.sec); |
| 810 | delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT); |
| 811 | pps_freq = ftemp; |
| 812 | if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) { |
| 813 | pr_warning("hardpps: PPSWANDER: change=%ld\n", delta); |
| 814 | time_status |= STA_PPSWANDER; |
| 815 | pps_stbcnt++; |
| 816 | pps_dec_freq_interval(); |
| 817 | } else { /* good sample */ |
| 818 | pps_inc_freq_interval(); |
| 819 | } |
| 820 | |
| 821 | /* the stability metric is calculated as the average of recent |
| 822 | * frequency changes, but is used only for performance |
| 823 | * monitoring |
| 824 | */ |
| 825 | delta_mod = delta; |
| 826 | if (delta_mod < 0) |
| 827 | delta_mod = -delta_mod; |
| 828 | pps_stabil += (div_s64(((s64)delta_mod) << |
| 829 | (NTP_SCALE_SHIFT - SHIFT_USEC), |
| 830 | NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN; |
| 831 | |
| 832 | /* if enabled, the system clock frequency is updated */ |
| 833 | if ((time_status & STA_PPSFREQ) != 0 && |
| 834 | (time_status & STA_FREQHOLD) == 0) { |
| 835 | time_freq = pps_freq; |
| 836 | ntp_update_frequency(); |
| 837 | } |
| 838 | |
| 839 | return delta; |
| 840 | } |
| 841 | |
| 842 | /* correct REALTIME clock phase error against PPS signal */ |
| 843 | static void hardpps_update_phase(long error) |
| 844 | { |
| 845 | long correction = -error; |
| 846 | long jitter; |
| 847 | |
| 848 | /* add the sample to the median filter */ |
| 849 | pps_phase_filter_add(correction); |
| 850 | correction = pps_phase_filter_get(&jitter); |
| 851 | |
| 852 | /* Nominal jitter is due to PPS signal noise. If it exceeds the |
| 853 | * threshold, the sample is discarded; otherwise, if so enabled, |
| 854 | * the time offset is updated. |
| 855 | */ |
| 856 | if (jitter > (pps_jitter << PPS_POPCORN)) { |
| 857 | pr_warning("hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", |
| 858 | jitter, (pps_jitter << PPS_POPCORN)); |
| 859 | time_status |= STA_PPSJITTER; |
| 860 | pps_jitcnt++; |
| 861 | } else if (time_status & STA_PPSTIME) { |
| 862 | /* correct the time using the phase offset */ |
| 863 | time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT, |
| 864 | NTP_INTERVAL_FREQ); |
| 865 | /* cancel running adjtime() */ |
| 866 | time_adjust = 0; |
| 867 | } |
| 868 | /* update jitter */ |
| 869 | pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN; |
| 870 | } |
| 871 | |
| 872 | /* |
| 873 | * hardpps() - discipline CPU clock oscillator to external PPS signal |
| 874 | * |
| 875 | * This routine is called at each PPS signal arrival in order to |
| 876 | * discipline the CPU clock oscillator to the PPS signal. It takes two |
| 877 | * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former |
| 878 | * is used to correct clock phase error and the latter is used to |
| 879 | * correct the frequency. |
| 880 | * |
| 881 | * This code is based on David Mills's reference nanokernel |
| 882 | * implementation. It was mostly rewritten but keeps the same idea. |
| 883 | */ |
| 884 | void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) |
| 885 | { |
| 886 | struct pps_normtime pts_norm, freq_norm; |
| 887 | unsigned long flags; |
| 888 | |
| 889 | pts_norm = pps_normalize_ts(*phase_ts); |
| 890 | |
| 891 | write_seqlock_irqsave(&xtime_lock, flags); |
| 892 | |
| 893 | /* clear the error bits, they will be set again if needed */ |
| 894 | time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); |
| 895 | |
| 896 | /* indicate signal presence */ |
| 897 | time_status |= STA_PPSSIGNAL; |
| 898 | pps_valid = PPS_VALID; |
| 899 | |
| 900 | /* when called for the first time, |
| 901 | * just start the frequency interval */ |
| 902 | if (unlikely(pps_fbase.tv_sec == 0)) { |
| 903 | pps_fbase = *raw_ts; |
| 904 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 905 | return; |
| 906 | } |
| 907 | |
| 908 | /* ok, now we have a base for frequency calculation */ |
| 909 | freq_norm = pps_normalize_ts(timespec_sub(*raw_ts, pps_fbase)); |
| 910 | |
| 911 | /* check that the signal is in the range |
| 912 | * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */ |
| 913 | if ((freq_norm.sec == 0) || |
| 914 | (freq_norm.nsec > MAXFREQ * freq_norm.sec) || |
| 915 | (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) { |
| 916 | time_status |= STA_PPSJITTER; |
| 917 | /* restart the frequency calibration interval */ |
| 918 | pps_fbase = *raw_ts; |
| 919 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 920 | pr_err("hardpps: PPSJITTER: bad pulse\n"); |
| 921 | return; |
| 922 | } |
| 923 | |
| 924 | /* signal is ok */ |
| 925 | |
| 926 | /* check if the current frequency interval is finished */ |
| 927 | if (freq_norm.sec >= (1 << pps_shift)) { |
| 928 | pps_calcnt++; |
| 929 | /* restart the frequency calibration interval */ |
| 930 | pps_fbase = *raw_ts; |
| 931 | hardpps_update_freq(freq_norm); |
| 932 | } |
| 933 | |
| 934 | hardpps_update_phase(pts_norm.nsec); |
| 935 | |
| 936 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 937 | } |
| 938 | EXPORT_SYMBOL(hardpps); |
| 939 | |
| 940 | #endif /* CONFIG_NTP_PPS */ |
| 941 | |
Roman Zippel | 10a398d | 2008-03-04 15:14:26 -0800 | [diff] [blame] | 942 | static int __init ntp_tick_adj_setup(char *str) |
| 943 | { |
| 944 | ntp_tick_adj = simple_strtol(str, NULL, 0); |
Ingo Molnar | 069569e | 2009-02-22 16:03:37 +0100 | [diff] [blame] | 945 | ntp_tick_adj <<= NTP_SCALE_SHIFT; |
| 946 | |
Roman Zippel | 10a398d | 2008-03-04 15:14:26 -0800 | [diff] [blame] | 947 | return 1; |
| 948 | } |
| 949 | |
| 950 | __setup("ntp_tick_adj=", ntp_tick_adj_setup); |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 951 | |
| 952 | void __init ntp_init(void) |
| 953 | { |
| 954 | ntp_clear(); |
| 955 | hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS); |
| 956 | leap_timer.function = ntp_leap_second; |
| 957 | } |