john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/time/timekeeping.c |
| 3 | * |
| 4 | * Kernel timekeeping code and accessor functions |
| 5 | * |
| 6 | * This code was moved from linux/kernel/timer.c. |
| 7 | * Please see that file for copyright and history logs. |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/interrupt.h> |
| 13 | #include <linux/percpu.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/mm.h> |
Alexey Dobriyan | d43c36d | 2009-10-07 17:09:06 +0400 | [diff] [blame] | 16 | #include <linux/sched.h> |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 17 | #include <linux/sysdev.h> |
| 18 | #include <linux/clocksource.h> |
| 19 | #include <linux/jiffies.h> |
| 20 | #include <linux/time.h> |
| 21 | #include <linux/tick.h> |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 22 | #include <linux/stop_machine.h> |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 23 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 24 | /* Structure holding internal timekeeping values. */ |
| 25 | struct timekeeper { |
| 26 | /* Current clocksource used for timekeeping. */ |
| 27 | struct clocksource *clock; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 28 | /* The shift value of the current clocksource. */ |
| 29 | int shift; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 30 | |
| 31 | /* Number of clock cycles in one NTP interval. */ |
| 32 | cycle_t cycle_interval; |
| 33 | /* Number of clock shifted nano seconds in one NTP interval. */ |
| 34 | u64 xtime_interval; |
| 35 | /* Raw nano seconds accumulated per NTP interval. */ |
| 36 | u32 raw_interval; |
| 37 | |
| 38 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ |
| 39 | u64 xtime_nsec; |
| 40 | /* Difference between accumulated time and NTP time in ntp |
| 41 | * shifted nano seconds. */ |
| 42 | s64 ntp_error; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 43 | /* Shift conversion between clock shifted nano seconds and |
| 44 | * ntp shifted nano seconds. */ |
| 45 | int ntp_error_shift; |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 46 | /* NTP adjusted clock multiplier */ |
| 47 | u32 mult; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 48 | }; |
| 49 | |
| 50 | struct timekeeper timekeeper; |
| 51 | |
| 52 | /** |
| 53 | * timekeeper_setup_internals - Set up internals to use clocksource clock. |
| 54 | * |
| 55 | * @clock: Pointer to clocksource. |
| 56 | * |
| 57 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment |
| 58 | * pair and interval request. |
| 59 | * |
| 60 | * Unless you're the timekeeping code, you should not be using this! |
| 61 | */ |
| 62 | static void timekeeper_setup_internals(struct clocksource *clock) |
| 63 | { |
| 64 | cycle_t interval; |
| 65 | u64 tmp; |
| 66 | |
| 67 | timekeeper.clock = clock; |
| 68 | clock->cycle_last = clock->read(clock); |
| 69 | |
| 70 | /* Do the ns -> cycle conversion first, using original mult */ |
| 71 | tmp = NTP_INTERVAL_LENGTH; |
| 72 | tmp <<= clock->shift; |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 73 | tmp += clock->mult/2; |
| 74 | do_div(tmp, clock->mult); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 75 | if (tmp == 0) |
| 76 | tmp = 1; |
| 77 | |
| 78 | interval = (cycle_t) tmp; |
| 79 | timekeeper.cycle_interval = interval; |
| 80 | |
| 81 | /* Go back from cycles -> shifted ns */ |
| 82 | timekeeper.xtime_interval = (u64) interval * clock->mult; |
| 83 | timekeeper.raw_interval = |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 84 | ((u64) interval * clock->mult) >> clock->shift; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 85 | |
| 86 | timekeeper.xtime_nsec = 0; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 87 | timekeeper.shift = clock->shift; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 88 | |
| 89 | timekeeper.ntp_error = 0; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 90 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 91 | |
| 92 | /* |
| 93 | * The timekeeper keeps its own mult values for the currently |
| 94 | * active clocksource. These value will be adjusted via NTP |
| 95 | * to counteract clock drifting. |
| 96 | */ |
| 97 | timekeeper.mult = clock->mult; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 98 | } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 99 | |
Martin Schwidefsky | 2ba2a30 | 2009-08-14 15:47:29 +0200 | [diff] [blame] | 100 | /* Timekeeper helper functions. */ |
| 101 | static inline s64 timekeeping_get_ns(void) |
| 102 | { |
| 103 | cycle_t cycle_now, cycle_delta; |
| 104 | struct clocksource *clock; |
| 105 | |
| 106 | /* read clocksource: */ |
| 107 | clock = timekeeper.clock; |
| 108 | cycle_now = clock->read(clock); |
| 109 | |
| 110 | /* calculate the delta since the last update_wall_time: */ |
| 111 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| 112 | |
| 113 | /* return delta convert to nanoseconds using ntp adjusted mult. */ |
| 114 | return clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
| 115 | timekeeper.shift); |
| 116 | } |
| 117 | |
| 118 | static inline s64 timekeeping_get_ns_raw(void) |
| 119 | { |
| 120 | cycle_t cycle_now, cycle_delta; |
| 121 | struct clocksource *clock; |
| 122 | |
| 123 | /* read clocksource: */ |
| 124 | clock = timekeeper.clock; |
| 125 | cycle_now = clock->read(clock); |
| 126 | |
| 127 | /* calculate the delta since the last update_wall_time: */ |
| 128 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| 129 | |
| 130 | /* return delta convert to nanoseconds using ntp adjusted mult. */ |
| 131 | return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
| 132 | } |
| 133 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 134 | /* |
| 135 | * This read-write spinlock protects us from races in SMP while |
Thomas Gleixner | dce48a8 | 2009-04-11 10:43:41 +0200 | [diff] [blame] | 136 | * playing with xtime. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 137 | */ |
Adrian Bunk | ba2a631 | 2007-10-16 23:27:16 -0700 | [diff] [blame] | 138 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 139 | |
| 140 | |
| 141 | /* |
| 142 | * The current time |
| 143 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected |
| 144 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged |
| 145 | * at zero at system boot time, so wall_to_monotonic will be negative, |
| 146 | * however, we will ALWAYS keep the tv_nsec part positive so we can use |
| 147 | * the usual normalization. |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 148 | * |
| 149 | * wall_to_monotonic is moved after resume from suspend for the monotonic |
| 150 | * time not to jump. We need to add total_sleep_time to wall_to_monotonic |
| 151 | * to get the real boot based time offset. |
| 152 | * |
| 153 | * - wall_to_monotonic is no longer the boot time, getboottime must be |
| 154 | * used instead. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 155 | */ |
| 156 | struct timespec xtime __attribute__ ((aligned (16))); |
| 157 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 158 | static struct timespec total_sleep_time; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 159 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 160 | /* |
| 161 | * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. |
| 162 | */ |
| 163 | struct timespec raw_time; |
| 164 | |
Thomas Gleixner | 1c5745a | 2008-12-22 23:05:28 +0100 | [diff] [blame] | 165 | /* flag for if timekeeping is suspended */ |
| 166 | int __read_mostly timekeeping_suspended; |
| 167 | |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 168 | static struct timespec xtime_cache __attribute__ ((aligned (16))); |
| 169 | void update_xtime_cache(u64 nsec) |
| 170 | { |
| 171 | xtime_cache = xtime; |
| 172 | timespec_add_ns(&xtime_cache, nsec); |
| 173 | } |
| 174 | |
John Stultz | 31089c1 | 2009-08-14 15:47:18 +0200 | [diff] [blame] | 175 | /* must hold xtime_lock */ |
| 176 | void timekeeping_leap_insert(int leapsecond) |
| 177 | { |
| 178 | xtime.tv_sec += leapsecond; |
| 179 | wall_to_monotonic.tv_sec -= leapsecond; |
Lin Ming | 0696b71 | 2009-11-17 13:49:50 +0800 | [diff] [blame] | 180 | update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); |
John Stultz | 31089c1 | 2009-08-14 15:47:18 +0200 | [diff] [blame] | 181 | } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 182 | |
| 183 | #ifdef CONFIG_GENERIC_TIME |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 184 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 185 | /** |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 186 | * timekeeping_forward_now - update clock to the current time |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 187 | * |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 188 | * Forward the current clock to update its state since the last call to |
| 189 | * update_wall_time(). This is useful before significant clock changes, |
| 190 | * as it avoids having to deal with this time offset explicitly. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 191 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 192 | static void timekeeping_forward_now(void) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 193 | { |
| 194 | cycle_t cycle_now, cycle_delta; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 195 | struct clocksource *clock; |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 196 | s64 nsec; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 197 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 198 | clock = timekeeper.clock; |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 199 | cycle_now = clock->read(clock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 200 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 201 | clock->cycle_last = cycle_now; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 202 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 203 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
| 204 | timekeeper.shift); |
john stultz | 7d27558 | 2009-05-01 13:10:26 -0700 | [diff] [blame] | 205 | |
| 206 | /* If arch requires, add in gettimeoffset() */ |
| 207 | nsec += arch_gettimeoffset(); |
| 208 | |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 209 | timespec_add_ns(&xtime, nsec); |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 210 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 211 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 212 | timespec_add_ns(&raw_time, nsec); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 213 | } |
| 214 | |
| 215 | /** |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 216 | * getnstimeofday - Returns the time of day in a timespec |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 217 | * @ts: pointer to the timespec to be set |
| 218 | * |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 219 | * Returns the time of day in a timespec. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 220 | */ |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 221 | void getnstimeofday(struct timespec *ts) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 222 | { |
| 223 | unsigned long seq; |
| 224 | s64 nsecs; |
| 225 | |
Thomas Gleixner | 1c5745a | 2008-12-22 23:05:28 +0100 | [diff] [blame] | 226 | WARN_ON(timekeeping_suspended); |
| 227 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 228 | do { |
| 229 | seq = read_seqbegin(&xtime_lock); |
| 230 | |
| 231 | *ts = xtime; |
Martin Schwidefsky | 2ba2a30 | 2009-08-14 15:47:29 +0200 | [diff] [blame] | 232 | nsecs = timekeeping_get_ns(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 233 | |
john stultz | 7d27558 | 2009-05-01 13:10:26 -0700 | [diff] [blame] | 234 | /* If arch requires, add in gettimeoffset() */ |
| 235 | nsecs += arch_gettimeoffset(); |
| 236 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 237 | } while (read_seqretry(&xtime_lock, seq)); |
| 238 | |
| 239 | timespec_add_ns(ts, nsecs); |
| 240 | } |
| 241 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 242 | EXPORT_SYMBOL(getnstimeofday); |
| 243 | |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 244 | ktime_t ktime_get(void) |
| 245 | { |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 246 | unsigned int seq; |
| 247 | s64 secs, nsecs; |
| 248 | |
| 249 | WARN_ON(timekeeping_suspended); |
| 250 | |
| 251 | do { |
| 252 | seq = read_seqbegin(&xtime_lock); |
| 253 | secs = xtime.tv_sec + wall_to_monotonic.tv_sec; |
| 254 | nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; |
Martin Schwidefsky | 2ba2a30 | 2009-08-14 15:47:29 +0200 | [diff] [blame] | 255 | nsecs += timekeeping_get_ns(); |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 256 | |
| 257 | } while (read_seqretry(&xtime_lock, seq)); |
| 258 | /* |
| 259 | * Use ktime_set/ktime_add_ns to create a proper ktime on |
| 260 | * 32-bit architectures without CONFIG_KTIME_SCALAR. |
| 261 | */ |
| 262 | return ktime_add_ns(ktime_set(secs, 0), nsecs); |
| 263 | } |
| 264 | EXPORT_SYMBOL_GPL(ktime_get); |
| 265 | |
| 266 | /** |
| 267 | * ktime_get_ts - get the monotonic clock in timespec format |
| 268 | * @ts: pointer to timespec variable |
| 269 | * |
| 270 | * The function calculates the monotonic clock from the realtime |
| 271 | * clock and the wall_to_monotonic offset and stores the result |
| 272 | * in normalized timespec format in the variable pointed to by @ts. |
| 273 | */ |
| 274 | void ktime_get_ts(struct timespec *ts) |
| 275 | { |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 276 | struct timespec tomono; |
| 277 | unsigned int seq; |
| 278 | s64 nsecs; |
| 279 | |
| 280 | WARN_ON(timekeeping_suspended); |
| 281 | |
| 282 | do { |
| 283 | seq = read_seqbegin(&xtime_lock); |
| 284 | *ts = xtime; |
| 285 | tomono = wall_to_monotonic; |
Martin Schwidefsky | 2ba2a30 | 2009-08-14 15:47:29 +0200 | [diff] [blame] | 286 | nsecs = timekeeping_get_ns(); |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 287 | |
| 288 | } while (read_seqretry(&xtime_lock, seq)); |
| 289 | |
| 290 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, |
| 291 | ts->tv_nsec + tomono.tv_nsec + nsecs); |
| 292 | } |
| 293 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
| 294 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 295 | /** |
| 296 | * do_gettimeofday - Returns the time of day in a timeval |
| 297 | * @tv: pointer to the timeval to be set |
| 298 | * |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 299 | * NOTE: Users should be converted to using getnstimeofday() |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 300 | */ |
| 301 | void do_gettimeofday(struct timeval *tv) |
| 302 | { |
| 303 | struct timespec now; |
| 304 | |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 305 | getnstimeofday(&now); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 306 | tv->tv_sec = now.tv_sec; |
| 307 | tv->tv_usec = now.tv_nsec/1000; |
| 308 | } |
| 309 | |
| 310 | EXPORT_SYMBOL(do_gettimeofday); |
| 311 | /** |
| 312 | * do_settimeofday - Sets the time of day |
| 313 | * @tv: pointer to the timespec variable containing the new time |
| 314 | * |
| 315 | * Sets the time of day to the new time and update NTP and notify hrtimers |
| 316 | */ |
| 317 | int do_settimeofday(struct timespec *tv) |
| 318 | { |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 319 | struct timespec ts_delta; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 320 | unsigned long flags; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 321 | |
| 322 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 323 | return -EINVAL; |
| 324 | |
| 325 | write_seqlock_irqsave(&xtime_lock, flags); |
| 326 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 327 | timekeeping_forward_now(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 328 | |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 329 | ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec; |
| 330 | ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec; |
| 331 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 332 | |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 333 | xtime = *tv; |
| 334 | |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 335 | update_xtime_cache(0); |
| 336 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 337 | timekeeper.ntp_error = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 338 | ntp_clear(); |
| 339 | |
Lin Ming | 0696b71 | 2009-11-17 13:49:50 +0800 | [diff] [blame] | 340 | update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 341 | |
| 342 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 343 | |
| 344 | /* signal hrtimers about time change */ |
| 345 | clock_was_set(); |
| 346 | |
| 347 | return 0; |
| 348 | } |
| 349 | |
| 350 | EXPORT_SYMBOL(do_settimeofday); |
| 351 | |
| 352 | /** |
| 353 | * change_clocksource - Swaps clocksources if a new one is available |
| 354 | * |
| 355 | * Accumulates current time interval and initializes new clocksource |
| 356 | */ |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 357 | static int change_clocksource(void *data) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 358 | { |
Magnus Damm | 4614e6a | 2009-04-21 12:24:02 -0700 | [diff] [blame] | 359 | struct clocksource *new, *old; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 360 | |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 361 | new = (struct clocksource *) data; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 362 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 363 | timekeeping_forward_now(); |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 364 | if (!new->enable || new->enable(new) == 0) { |
| 365 | old = timekeeper.clock; |
| 366 | timekeeper_setup_internals(new); |
| 367 | if (old->disable) |
| 368 | old->disable(old); |
| 369 | } |
| 370 | return 0; |
| 371 | } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 372 | |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 373 | /** |
| 374 | * timekeeping_notify - Install a new clock source |
| 375 | * @clock: pointer to the clock source |
| 376 | * |
| 377 | * This function is called from clocksource.c after a new, better clock |
| 378 | * source has been registered. The caller holds the clocksource_mutex. |
| 379 | */ |
| 380 | void timekeeping_notify(struct clocksource *clock) |
| 381 | { |
| 382 | if (timekeeper.clock == clock) |
Magnus Damm | 4614e6a | 2009-04-21 12:24:02 -0700 | [diff] [blame] | 383 | return; |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 384 | stop_machine(change_clocksource, clock, NULL); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 385 | tick_clock_notify(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 386 | } |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 387 | |
Thomas Gleixner | a40f262 | 2009-07-07 13:00:31 +0200 | [diff] [blame] | 388 | #else /* GENERIC_TIME */ |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 389 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 390 | static inline void timekeeping_forward_now(void) { } |
Thomas Gleixner | a40f262 | 2009-07-07 13:00:31 +0200 | [diff] [blame] | 391 | |
| 392 | /** |
| 393 | * ktime_get - get the monotonic time in ktime_t format |
| 394 | * |
| 395 | * returns the time in ktime_t format |
| 396 | */ |
| 397 | ktime_t ktime_get(void) |
| 398 | { |
| 399 | struct timespec now; |
| 400 | |
| 401 | ktime_get_ts(&now); |
| 402 | |
| 403 | return timespec_to_ktime(now); |
| 404 | } |
| 405 | EXPORT_SYMBOL_GPL(ktime_get); |
| 406 | |
| 407 | /** |
| 408 | * ktime_get_ts - get the monotonic clock in timespec format |
| 409 | * @ts: pointer to timespec variable |
| 410 | * |
| 411 | * The function calculates the monotonic clock from the realtime |
| 412 | * clock and the wall_to_monotonic offset and stores the result |
| 413 | * in normalized timespec format in the variable pointed to by @ts. |
| 414 | */ |
| 415 | void ktime_get_ts(struct timespec *ts) |
| 416 | { |
| 417 | struct timespec tomono; |
| 418 | unsigned long seq; |
| 419 | |
| 420 | do { |
| 421 | seq = read_seqbegin(&xtime_lock); |
| 422 | getnstimeofday(ts); |
| 423 | tomono = wall_to_monotonic; |
| 424 | |
| 425 | } while (read_seqretry(&xtime_lock, seq)); |
| 426 | |
| 427 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, |
| 428 | ts->tv_nsec + tomono.tv_nsec); |
| 429 | } |
| 430 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
Martin Schwidefsky | 75c5158 | 2009-08-14 15:47:30 +0200 | [diff] [blame] | 431 | |
Thomas Gleixner | a40f262 | 2009-07-07 13:00:31 +0200 | [diff] [blame] | 432 | #endif /* !GENERIC_TIME */ |
| 433 | |
| 434 | /** |
| 435 | * ktime_get_real - get the real (wall-) time in ktime_t format |
| 436 | * |
| 437 | * returns the time in ktime_t format |
| 438 | */ |
| 439 | ktime_t ktime_get_real(void) |
| 440 | { |
| 441 | struct timespec now; |
| 442 | |
| 443 | getnstimeofday(&now); |
| 444 | |
| 445 | return timespec_to_ktime(now); |
| 446 | } |
| 447 | EXPORT_SYMBOL_GPL(ktime_get_real); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 448 | |
| 449 | /** |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 450 | * getrawmonotonic - Returns the raw monotonic time in a timespec |
| 451 | * @ts: pointer to the timespec to be set |
| 452 | * |
| 453 | * Returns the raw monotonic time (completely un-modified by ntp) |
| 454 | */ |
| 455 | void getrawmonotonic(struct timespec *ts) |
| 456 | { |
| 457 | unsigned long seq; |
| 458 | s64 nsecs; |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 459 | |
| 460 | do { |
| 461 | seq = read_seqbegin(&xtime_lock); |
Martin Schwidefsky | 2ba2a30 | 2009-08-14 15:47:29 +0200 | [diff] [blame] | 462 | nsecs = timekeeping_get_ns_raw(); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 463 | *ts = raw_time; |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 464 | |
| 465 | } while (read_seqretry(&xtime_lock, seq)); |
| 466 | |
| 467 | timespec_add_ns(ts, nsecs); |
| 468 | } |
| 469 | EXPORT_SYMBOL(getrawmonotonic); |
| 470 | |
| 471 | |
| 472 | /** |
Li Zefan | cf4fc6c | 2008-02-08 04:19:24 -0800 | [diff] [blame] | 473 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 474 | */ |
Li Zefan | cf4fc6c | 2008-02-08 04:19:24 -0800 | [diff] [blame] | 475 | int timekeeping_valid_for_hres(void) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 476 | { |
| 477 | unsigned long seq; |
| 478 | int ret; |
| 479 | |
| 480 | do { |
| 481 | seq = read_seqbegin(&xtime_lock); |
| 482 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 483 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 484 | |
| 485 | } while (read_seqretry(&xtime_lock, seq)); |
| 486 | |
| 487 | return ret; |
| 488 | } |
| 489 | |
| 490 | /** |
Jon Hunter | 9896246 | 2009-08-18 12:45:10 -0500 | [diff] [blame] | 491 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred |
| 492 | * |
| 493 | * Caller must observe xtime_lock via read_seqbegin/read_seqretry to |
| 494 | * ensure that the clocksource does not change! |
| 495 | */ |
| 496 | u64 timekeeping_max_deferment(void) |
| 497 | { |
| 498 | return timekeeper.clock->max_idle_ns; |
| 499 | } |
| 500 | |
| 501 | /** |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 502 | * read_persistent_clock - Return time from the persistent clock. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 503 | * |
| 504 | * Weak dummy function for arches that do not yet support it. |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 505 | * Reads the time from the battery backed persistent clock. |
| 506 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 507 | * |
| 508 | * XXX - Do be sure to remove it once all arches implement it. |
| 509 | */ |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 510 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 511 | { |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 512 | ts->tv_sec = 0; |
| 513 | ts->tv_nsec = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 514 | } |
| 515 | |
Martin Schwidefsky | 23970e3 | 2009-08-14 15:47:32 +0200 | [diff] [blame] | 516 | /** |
| 517 | * read_boot_clock - Return time of the system start. |
| 518 | * |
| 519 | * Weak dummy function for arches that do not yet support it. |
| 520 | * Function to read the exact time the system has been started. |
| 521 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. |
| 522 | * |
| 523 | * XXX - Do be sure to remove it once all arches implement it. |
| 524 | */ |
| 525 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) |
| 526 | { |
| 527 | ts->tv_sec = 0; |
| 528 | ts->tv_nsec = 0; |
| 529 | } |
| 530 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 531 | /* |
| 532 | * timekeeping_init - Initializes the clocksource and common timekeeping values |
| 533 | */ |
| 534 | void __init timekeeping_init(void) |
| 535 | { |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 536 | struct clocksource *clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 537 | unsigned long flags; |
Martin Schwidefsky | 23970e3 | 2009-08-14 15:47:32 +0200 | [diff] [blame] | 538 | struct timespec now, boot; |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 539 | |
| 540 | read_persistent_clock(&now); |
Martin Schwidefsky | 23970e3 | 2009-08-14 15:47:32 +0200 | [diff] [blame] | 541 | read_boot_clock(&boot); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 542 | |
| 543 | write_seqlock_irqsave(&xtime_lock, flags); |
| 544 | |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 545 | ntp_init(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 546 | |
Martin Schwidefsky | f1b8274 | 2009-08-14 15:47:21 +0200 | [diff] [blame] | 547 | clock = clocksource_default_clock(); |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 548 | if (clock->enable) |
| 549 | clock->enable(clock); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 550 | timekeeper_setup_internals(clock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 551 | |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 552 | xtime.tv_sec = now.tv_sec; |
| 553 | xtime.tv_nsec = now.tv_nsec; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 554 | raw_time.tv_sec = 0; |
| 555 | raw_time.tv_nsec = 0; |
Martin Schwidefsky | 23970e3 | 2009-08-14 15:47:32 +0200 | [diff] [blame] | 556 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) { |
| 557 | boot.tv_sec = xtime.tv_sec; |
| 558 | boot.tv_nsec = xtime.tv_nsec; |
| 559 | } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 560 | set_normalized_timespec(&wall_to_monotonic, |
Martin Schwidefsky | 23970e3 | 2009-08-14 15:47:32 +0200 | [diff] [blame] | 561 | -boot.tv_sec, -boot.tv_nsec); |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 562 | update_xtime_cache(0); |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 563 | total_sleep_time.tv_sec = 0; |
| 564 | total_sleep_time.tv_nsec = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 565 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 566 | } |
| 567 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 568 | /* time in seconds when suspend began */ |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 569 | static struct timespec timekeeping_suspend_time; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 570 | |
| 571 | /** |
| 572 | * timekeeping_resume - Resumes the generic timekeeping subsystem. |
| 573 | * @dev: unused |
| 574 | * |
| 575 | * This is for the generic clocksource timekeeping. |
| 576 | * xtime/wall_to_monotonic/jiffies/etc are |
| 577 | * still managed by arch specific suspend/resume code. |
| 578 | */ |
| 579 | static int timekeeping_resume(struct sys_device *dev) |
| 580 | { |
| 581 | unsigned long flags; |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 582 | struct timespec ts; |
| 583 | |
| 584 | read_persistent_clock(&ts); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 585 | |
Thomas Gleixner | d10ff3f | 2007-05-14 11:10:02 +0200 | [diff] [blame] | 586 | clocksource_resume(); |
| 587 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 588 | write_seqlock_irqsave(&xtime_lock, flags); |
| 589 | |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 590 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
| 591 | ts = timespec_sub(ts, timekeeping_suspend_time); |
| 592 | xtime = timespec_add_safe(xtime, ts); |
| 593 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts); |
| 594 | total_sleep_time = timespec_add_safe(total_sleep_time, ts); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 595 | } |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 596 | update_xtime_cache(0); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 597 | /* re-base the last cycle value */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 598 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
| 599 | timekeeper.ntp_error = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 600 | timekeeping_suspended = 0; |
| 601 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 602 | |
| 603 | touch_softlockup_watchdog(); |
| 604 | |
| 605 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); |
| 606 | |
| 607 | /* Resume hrtimers */ |
| 608 | hres_timers_resume(); |
| 609 | |
| 610 | return 0; |
| 611 | } |
| 612 | |
| 613 | static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) |
| 614 | { |
| 615 | unsigned long flags; |
| 616 | |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 617 | read_persistent_clock(&timekeeping_suspend_time); |
Thomas Gleixner | 3be9095 | 2007-09-16 15:36:43 +0200 | [diff] [blame] | 618 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 619 | write_seqlock_irqsave(&xtime_lock, flags); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 620 | timekeeping_forward_now(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 621 | timekeeping_suspended = 1; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 622 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 623 | |
| 624 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); |
Magnus Damm | c54a42b | 2010-02-02 14:41:41 -0800 | [diff] [blame] | 625 | clocksource_suspend(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 626 | |
| 627 | return 0; |
| 628 | } |
| 629 | |
| 630 | /* sysfs resume/suspend bits for timekeeping */ |
| 631 | static struct sysdev_class timekeeping_sysclass = { |
Kay Sievers | af5ca3f | 2007-12-20 02:09:39 +0100 | [diff] [blame] | 632 | .name = "timekeeping", |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 633 | .resume = timekeeping_resume, |
| 634 | .suspend = timekeeping_suspend, |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 635 | }; |
| 636 | |
| 637 | static struct sys_device device_timer = { |
| 638 | .id = 0, |
| 639 | .cls = &timekeeping_sysclass, |
| 640 | }; |
| 641 | |
| 642 | static int __init timekeeping_init_device(void) |
| 643 | { |
| 644 | int error = sysdev_class_register(&timekeeping_sysclass); |
| 645 | if (!error) |
| 646 | error = sysdev_register(&device_timer); |
| 647 | return error; |
| 648 | } |
| 649 | |
| 650 | device_initcall(timekeeping_init_device); |
| 651 | |
| 652 | /* |
| 653 | * If the error is already larger, we look ahead even further |
| 654 | * to compensate for late or lost adjustments. |
| 655 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 656 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 657 | s64 *offset) |
| 658 | { |
| 659 | s64 tick_error, i; |
| 660 | u32 look_ahead, adj; |
| 661 | s32 error2, mult; |
| 662 | |
| 663 | /* |
| 664 | * Use the current error value to determine how much to look ahead. |
| 665 | * The larger the error the slower we adjust for it to avoid problems |
| 666 | * with losing too many ticks, otherwise we would overadjust and |
| 667 | * produce an even larger error. The smaller the adjustment the |
| 668 | * faster we try to adjust for it, as lost ticks can do less harm |
Li Zefan | 3eb0567 | 2008-02-08 04:19:25 -0800 | [diff] [blame] | 669 | * here. This is tuned so that an error of about 1 msec is adjusted |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 670 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
| 671 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 672 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 673 | error2 = abs(error2); |
| 674 | for (look_ahead = 0; error2 > 0; look_ahead++) |
| 675 | error2 >>= 2; |
| 676 | |
| 677 | /* |
| 678 | * Now calculate the error in (1 << look_ahead) ticks, but first |
| 679 | * remove the single look ahead already included in the error. |
| 680 | */ |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 681 | tick_error = tick_length >> (timekeeper.ntp_error_shift + 1); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 682 | tick_error -= timekeeper.xtime_interval >> 1; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 683 | error = ((error - tick_error) >> look_ahead) + tick_error; |
| 684 | |
| 685 | /* Finally calculate the adjustment shift value. */ |
| 686 | i = *interval; |
| 687 | mult = 1; |
| 688 | if (error < 0) { |
| 689 | error = -error; |
| 690 | *interval = -*interval; |
| 691 | *offset = -*offset; |
| 692 | mult = -1; |
| 693 | } |
| 694 | for (adj = 0; error > i; adj++) |
| 695 | error >>= 1; |
| 696 | |
| 697 | *interval <<= adj; |
| 698 | *offset <<= adj; |
| 699 | return mult << adj; |
| 700 | } |
| 701 | |
| 702 | /* |
| 703 | * Adjust the multiplier to reduce the error value, |
| 704 | * this is optimized for the most common adjustments of -1,0,1, |
| 705 | * for other values we can do a bit more work. |
| 706 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 707 | static void timekeeping_adjust(s64 offset) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 708 | { |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 709 | s64 error, interval = timekeeper.cycle_interval; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 710 | int adj; |
| 711 | |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 712 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 713 | if (error > interval) { |
| 714 | error >>= 2; |
| 715 | if (likely(error <= interval)) |
| 716 | adj = 1; |
| 717 | else |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 718 | adj = timekeeping_bigadjust(error, &interval, &offset); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 719 | } else if (error < -interval) { |
| 720 | error >>= 2; |
| 721 | if (likely(error >= -interval)) { |
| 722 | adj = -1; |
| 723 | interval = -interval; |
| 724 | offset = -offset; |
| 725 | } else |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 726 | adj = timekeeping_bigadjust(error, &interval, &offset); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 727 | } else |
| 728 | return; |
| 729 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame] | 730 | timekeeper.mult += adj; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 731 | timekeeper.xtime_interval += interval; |
| 732 | timekeeper.xtime_nsec -= offset; |
| 733 | timekeeper.ntp_error -= (interval - offset) << |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 734 | timekeeper.ntp_error_shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 735 | } |
| 736 | |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 737 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 738 | /** |
john stultz | a092ff0 | 2009-10-02 16:17:53 -0700 | [diff] [blame] | 739 | * logarithmic_accumulation - shifted accumulation of cycles |
| 740 | * |
| 741 | * This functions accumulates a shifted interval of cycles into |
| 742 | * into a shifted interval nanoseconds. Allows for O(log) accumulation |
| 743 | * loop. |
| 744 | * |
| 745 | * Returns the unconsumed cycles. |
| 746 | */ |
| 747 | static cycle_t logarithmic_accumulation(cycle_t offset, int shift) |
| 748 | { |
| 749 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; |
| 750 | |
| 751 | /* If the offset is smaller then a shifted interval, do nothing */ |
| 752 | if (offset < timekeeper.cycle_interval<<shift) |
| 753 | return offset; |
| 754 | |
| 755 | /* Accumulate one shifted interval */ |
| 756 | offset -= timekeeper.cycle_interval << shift; |
| 757 | timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift; |
| 758 | |
| 759 | timekeeper.xtime_nsec += timekeeper.xtime_interval << shift; |
| 760 | while (timekeeper.xtime_nsec >= nsecps) { |
| 761 | timekeeper.xtime_nsec -= nsecps; |
| 762 | xtime.tv_sec++; |
| 763 | second_overflow(); |
| 764 | } |
| 765 | |
| 766 | /* Accumulate into raw time */ |
| 767 | raw_time.tv_nsec += timekeeper.raw_interval << shift;; |
| 768 | while (raw_time.tv_nsec >= NSEC_PER_SEC) { |
| 769 | raw_time.tv_nsec -= NSEC_PER_SEC; |
| 770 | raw_time.tv_sec++; |
| 771 | } |
| 772 | |
| 773 | /* Accumulate error between NTP and clock interval */ |
| 774 | timekeeper.ntp_error += tick_length << shift; |
| 775 | timekeeper.ntp_error -= timekeeper.xtime_interval << |
| 776 | (timekeeper.ntp_error_shift + shift); |
| 777 | |
| 778 | return offset; |
| 779 | } |
| 780 | |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 781 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 782 | /** |
| 783 | * update_wall_time - Uses the current clocksource to increment the wall time |
| 784 | * |
| 785 | * Called from the timer interrupt, must hold a write on xtime_lock. |
| 786 | */ |
| 787 | void update_wall_time(void) |
| 788 | { |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 789 | struct clocksource *clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 790 | cycle_t offset; |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 791 | u64 nsecs; |
john stultz | a092ff0 | 2009-10-02 16:17:53 -0700 | [diff] [blame] | 792 | int shift = 0, maxshift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 793 | |
| 794 | /* Make sure we're fully resumed: */ |
| 795 | if (unlikely(timekeeping_suspended)) |
| 796 | return; |
| 797 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 798 | clock = timekeeper.clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 799 | #ifdef CONFIG_GENERIC_TIME |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 800 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 801 | #else |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 802 | offset = timekeeper.cycle_interval; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 803 | #endif |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 804 | timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 805 | |
john stultz | a092ff0 | 2009-10-02 16:17:53 -0700 | [diff] [blame] | 806 | /* |
| 807 | * With NO_HZ we may have to accumulate many cycle_intervals |
| 808 | * (think "ticks") worth of time at once. To do this efficiently, |
| 809 | * we calculate the largest doubling multiple of cycle_intervals |
| 810 | * that is smaller then the offset. We then accumulate that |
| 811 | * chunk in one go, and then try to consume the next smaller |
| 812 | * doubled multiple. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 813 | */ |
john stultz | a092ff0 | 2009-10-02 16:17:53 -0700 | [diff] [blame] | 814 | shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); |
| 815 | shift = max(0, shift); |
| 816 | /* Bound shift to one less then what overflows tick_length */ |
| 817 | maxshift = (8*sizeof(tick_length) - (ilog2(tick_length)+1)) - 1; |
| 818 | shift = min(shift, maxshift); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 819 | while (offset >= timekeeper.cycle_interval) { |
john stultz | a092ff0 | 2009-10-02 16:17:53 -0700 | [diff] [blame] | 820 | offset = logarithmic_accumulation(offset, shift); |
John Stultz | 830ec04 | 2010-03-18 14:47:30 -0700 | [diff] [blame] | 821 | if(offset < timekeeper.cycle_interval<<shift) |
| 822 | shift--; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 823 | } |
| 824 | |
| 825 | /* correct the clock when NTP error is too big */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 826 | timekeeping_adjust(offset); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 827 | |
john stultz | 6c9bacb | 2008-12-01 18:34:41 -0800 | [diff] [blame] | 828 | /* |
| 829 | * Since in the loop above, we accumulate any amount of time |
| 830 | * in xtime_nsec over a second into xtime.tv_sec, its possible for |
| 831 | * xtime_nsec to be fairly small after the loop. Further, if we're |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 832 | * slightly speeding the clocksource up in timekeeping_adjust(), |
john stultz | 6c9bacb | 2008-12-01 18:34:41 -0800 | [diff] [blame] | 833 | * its possible the required corrective factor to xtime_nsec could |
| 834 | * cause it to underflow. |
| 835 | * |
| 836 | * Now, we cannot simply roll the accumulated second back, since |
| 837 | * the NTP subsystem has been notified via second_overflow. So |
| 838 | * instead we push xtime_nsec forward by the amount we underflowed, |
| 839 | * and add that amount into the error. |
| 840 | * |
| 841 | * We'll correct this error next time through this function, when |
| 842 | * xtime_nsec is not as small. |
| 843 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 844 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
| 845 | s64 neg = -(s64)timekeeper.xtime_nsec; |
| 846 | timekeeper.xtime_nsec = 0; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 847 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
john stultz | 6c9bacb | 2008-12-01 18:34:41 -0800 | [diff] [blame] | 848 | } |
| 849 | |
Roman Zippel | 5cd1c9c | 2008-09-22 14:42:43 -0700 | [diff] [blame] | 850 | /* store full nanoseconds into xtime after rounding it up and |
| 851 | * add the remainder to the error difference. |
| 852 | */ |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 853 | xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1; |
| 854 | timekeeper.xtime_nsec -= (s64) xtime.tv_nsec << timekeeper.shift; |
| 855 | timekeeper.ntp_error += timekeeper.xtime_nsec << |
| 856 | timekeeper.ntp_error_shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 857 | |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 858 | nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift); |
| 859 | update_xtime_cache(nsecs); |
| 860 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 861 | /* check to see if there is a new clocksource to use */ |
Lin Ming | 0696b71 | 2009-11-17 13:49:50 +0800 | [diff] [blame] | 862 | update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 863 | } |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 864 | |
| 865 | /** |
| 866 | * getboottime - Return the real time of system boot. |
| 867 | * @ts: pointer to the timespec to be set |
| 868 | * |
| 869 | * Returns the time of day in a timespec. |
| 870 | * |
| 871 | * This is based on the wall_to_monotonic offset and the total suspend |
| 872 | * time. Calls to settimeofday will affect the value returned (which |
| 873 | * basically means that however wrong your real time clock is at boot time, |
| 874 | * you get the right time here). |
| 875 | */ |
| 876 | void getboottime(struct timespec *ts) |
| 877 | { |
Hiroshi Shimamoto | 36d4748 | 2009-08-25 15:08:30 +0900 | [diff] [blame] | 878 | struct timespec boottime = { |
| 879 | .tv_sec = wall_to_monotonic.tv_sec + total_sleep_time.tv_sec, |
| 880 | .tv_nsec = wall_to_monotonic.tv_nsec + total_sleep_time.tv_nsec |
| 881 | }; |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 882 | |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 883 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 884 | } |
Jason Wang | c93d89f | 2010-01-27 19:13:40 +0800 | [diff] [blame] | 885 | EXPORT_SYMBOL_GPL(getboottime); |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 886 | |
| 887 | /** |
| 888 | * monotonic_to_bootbased - Convert the monotonic time to boot based. |
| 889 | * @ts: pointer to the timespec to be converted |
| 890 | */ |
| 891 | void monotonic_to_bootbased(struct timespec *ts) |
| 892 | { |
Martin Schwidefsky | d4f587c | 2009-08-14 15:47:31 +0200 | [diff] [blame] | 893 | *ts = timespec_add_safe(*ts, total_sleep_time); |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 894 | } |
Jason Wang | c93d89f | 2010-01-27 19:13:40 +0800 | [diff] [blame] | 895 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 896 | |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 897 | unsigned long get_seconds(void) |
| 898 | { |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 899 | return xtime_cache.tv_sec; |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 900 | } |
| 901 | EXPORT_SYMBOL(get_seconds); |
| 902 | |
john stultz | da15cfd | 2009-08-19 19:13:34 -0700 | [diff] [blame] | 903 | struct timespec __current_kernel_time(void) |
| 904 | { |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 905 | return xtime_cache; |
john stultz | da15cfd | 2009-08-19 19:13:34 -0700 | [diff] [blame] | 906 | } |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 907 | |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 908 | struct timespec current_kernel_time(void) |
| 909 | { |
| 910 | struct timespec now; |
| 911 | unsigned long seq; |
| 912 | |
| 913 | do { |
| 914 | seq = read_seqbegin(&xtime_lock); |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 915 | |
| 916 | now = xtime_cache; |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 917 | } while (read_seqretry(&xtime_lock, seq)); |
| 918 | |
| 919 | return now; |
| 920 | } |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 921 | EXPORT_SYMBOL(current_kernel_time); |
john stultz | da15cfd | 2009-08-19 19:13:34 -0700 | [diff] [blame] | 922 | |
| 923 | struct timespec get_monotonic_coarse(void) |
| 924 | { |
| 925 | struct timespec now, mono; |
| 926 | unsigned long seq; |
| 927 | |
| 928 | do { |
| 929 | seq = read_seqbegin(&xtime_lock); |
Linus Torvalds | 83f57a1 | 2009-12-22 14:10:37 -0800 | [diff] [blame] | 930 | |
| 931 | now = xtime_cache; |
john stultz | da15cfd | 2009-08-19 19:13:34 -0700 | [diff] [blame] | 932 | mono = wall_to_monotonic; |
| 933 | } while (read_seqretry(&xtime_lock, seq)); |
| 934 | |
| 935 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, |
| 936 | now.tv_nsec + mono.tv_nsec); |
| 937 | return now; |
| 938 | } |