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> |
| 16 | #include <linux/sysdev.h> |
| 17 | #include <linux/clocksource.h> |
| 18 | #include <linux/jiffies.h> |
| 19 | #include <linux/time.h> |
| 20 | #include <linux/tick.h> |
| 21 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 22 | /* Structure holding internal timekeeping values. */ |
| 23 | struct timekeeper { |
| 24 | /* Current clocksource used for timekeeping. */ |
| 25 | struct clocksource *clock; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 26 | /* The shift value of the current clocksource. */ |
| 27 | int shift; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 28 | |
| 29 | /* Number of clock cycles in one NTP interval. */ |
| 30 | cycle_t cycle_interval; |
| 31 | /* Number of clock shifted nano seconds in one NTP interval. */ |
| 32 | u64 xtime_interval; |
| 33 | /* Raw nano seconds accumulated per NTP interval. */ |
| 34 | u32 raw_interval; |
| 35 | |
| 36 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ |
| 37 | u64 xtime_nsec; |
| 38 | /* Difference between accumulated time and NTP time in ntp |
| 39 | * shifted nano seconds. */ |
| 40 | s64 ntp_error; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 41 | /* Shift conversion between clock shifted nano seconds and |
| 42 | * ntp shifted nano seconds. */ |
| 43 | int ntp_error_shift; |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 44 | /* NTP adjusted clock multiplier */ |
| 45 | u32 mult; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 46 | }; |
| 47 | |
| 48 | struct timekeeper timekeeper; |
| 49 | |
| 50 | /** |
| 51 | * timekeeper_setup_internals - Set up internals to use clocksource clock. |
| 52 | * |
| 53 | * @clock: Pointer to clocksource. |
| 54 | * |
| 55 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment |
| 56 | * pair and interval request. |
| 57 | * |
| 58 | * Unless you're the timekeeping code, you should not be using this! |
| 59 | */ |
| 60 | static void timekeeper_setup_internals(struct clocksource *clock) |
| 61 | { |
| 62 | cycle_t interval; |
| 63 | u64 tmp; |
| 64 | |
| 65 | timekeeper.clock = clock; |
| 66 | clock->cycle_last = clock->read(clock); |
| 67 | |
| 68 | /* Do the ns -> cycle conversion first, using original mult */ |
| 69 | tmp = NTP_INTERVAL_LENGTH; |
| 70 | tmp <<= clock->shift; |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 71 | tmp += clock->mult/2; |
| 72 | do_div(tmp, clock->mult); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 73 | if (tmp == 0) |
| 74 | tmp = 1; |
| 75 | |
| 76 | interval = (cycle_t) tmp; |
| 77 | timekeeper.cycle_interval = interval; |
| 78 | |
| 79 | /* Go back from cycles -> shifted ns */ |
| 80 | timekeeper.xtime_interval = (u64) interval * clock->mult; |
| 81 | timekeeper.raw_interval = |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 82 | ((u64) interval * clock->mult) >> clock->shift; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 83 | |
| 84 | timekeeper.xtime_nsec = 0; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 85 | timekeeper.shift = clock->shift; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 86 | |
| 87 | timekeeper.ntp_error = 0; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 88 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 89 | |
| 90 | /* |
| 91 | * The timekeeper keeps its own mult values for the currently |
| 92 | * active clocksource. These value will be adjusted via NTP |
| 93 | * to counteract clock drifting. |
| 94 | */ |
| 95 | timekeeper.mult = clock->mult; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 96 | } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 97 | |
| 98 | /* |
| 99 | * This read-write spinlock protects us from races in SMP while |
Thomas Gleixner | dce48a8 | 2009-04-11 10:43:41 +0200 | [diff] [blame] | 100 | * playing with xtime. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 101 | */ |
Adrian Bunk | ba2a631 | 2007-10-16 23:27:16 -0700 | [diff] [blame] | 102 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 103 | |
| 104 | |
| 105 | /* |
| 106 | * The current time |
| 107 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected |
| 108 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged |
| 109 | * at zero at system boot time, so wall_to_monotonic will be negative, |
| 110 | * however, we will ALWAYS keep the tv_nsec part positive so we can use |
| 111 | * the usual normalization. |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 112 | * |
| 113 | * wall_to_monotonic is moved after resume from suspend for the monotonic |
| 114 | * time not to jump. We need to add total_sleep_time to wall_to_monotonic |
| 115 | * to get the real boot based time offset. |
| 116 | * |
| 117 | * - wall_to_monotonic is no longer the boot time, getboottime must be |
| 118 | * used instead. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 119 | */ |
| 120 | struct timespec xtime __attribute__ ((aligned (16))); |
| 121 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 122 | static unsigned long total_sleep_time; /* seconds */ |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 123 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 124 | /* |
| 125 | * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. |
| 126 | */ |
| 127 | struct timespec raw_time; |
| 128 | |
Thomas Gleixner | 1c5745a | 2008-12-22 23:05:28 +0100 | [diff] [blame] | 129 | /* flag for if timekeeping is suspended */ |
| 130 | int __read_mostly timekeeping_suspended; |
| 131 | |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 132 | static struct timespec xtime_cache __attribute__ ((aligned (16))); |
Thomas Gleixner | 1001d0a | 2008-02-01 17:45:13 +0100 | [diff] [blame] | 133 | void update_xtime_cache(u64 nsec) |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 134 | { |
| 135 | xtime_cache = xtime; |
| 136 | timespec_add_ns(&xtime_cache, nsec); |
| 137 | } |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 138 | |
John Stultz | 31089c1 | 2009-08-14 15:47:18 +0200 | [diff] [blame] | 139 | /* must hold xtime_lock */ |
| 140 | void timekeeping_leap_insert(int leapsecond) |
| 141 | { |
| 142 | xtime.tv_sec += leapsecond; |
| 143 | wall_to_monotonic.tv_sec -= leapsecond; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 144 | update_vsyscall(&xtime, timekeeper.clock); |
John Stultz | 31089c1 | 2009-08-14 15:47:18 +0200 | [diff] [blame] | 145 | } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 146 | |
| 147 | #ifdef CONFIG_GENERIC_TIME |
| 148 | /** |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 149 | * timekeeping_forward_now - update clock to the current time |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 150 | * |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 151 | * Forward the current clock to update its state since the last call to |
| 152 | * update_wall_time(). This is useful before significant clock changes, |
| 153 | * as it avoids having to deal with this time offset explicitly. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 154 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 155 | static void timekeeping_forward_now(void) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 156 | { |
| 157 | cycle_t cycle_now, cycle_delta; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 158 | struct clocksource *clock; |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 159 | s64 nsec; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 160 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 161 | clock = timekeeper.clock; |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 162 | cycle_now = clock->read(clock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 163 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 164 | clock->cycle_last = cycle_now; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 165 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 166 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
| 167 | timekeeper.shift); |
john stultz | 7d27558 | 2009-05-01 13:10:26 -0700 | [diff] [blame] | 168 | |
| 169 | /* If arch requires, add in gettimeoffset() */ |
| 170 | nsec += arch_gettimeoffset(); |
| 171 | |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 172 | timespec_add_ns(&xtime, nsec); |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 173 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 174 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 175 | timespec_add_ns(&raw_time, nsec); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 176 | } |
| 177 | |
| 178 | /** |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 179 | * getnstimeofday - Returns the time of day in a timespec |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 180 | * @ts: pointer to the timespec to be set |
| 181 | * |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 182 | * Returns the time of day in a timespec. |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 183 | */ |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 184 | void getnstimeofday(struct timespec *ts) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 185 | { |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 186 | cycle_t cycle_now, cycle_delta; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 187 | struct clocksource *clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 188 | unsigned long seq; |
| 189 | s64 nsecs; |
| 190 | |
Thomas Gleixner | 1c5745a | 2008-12-22 23:05:28 +0100 | [diff] [blame] | 191 | WARN_ON(timekeeping_suspended); |
| 192 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 193 | do { |
| 194 | seq = read_seqbegin(&xtime_lock); |
| 195 | |
| 196 | *ts = xtime; |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 197 | |
| 198 | /* read clocksource: */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 199 | clock = timekeeper.clock; |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 200 | cycle_now = clock->read(clock); |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 201 | |
| 202 | /* calculate the delta since the last update_wall_time: */ |
| 203 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| 204 | |
| 205 | /* convert to nanoseconds: */ |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 206 | nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
| 207 | timekeeper.shift); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 208 | |
john stultz | 7d27558 | 2009-05-01 13:10:26 -0700 | [diff] [blame] | 209 | /* If arch requires, add in gettimeoffset() */ |
| 210 | nsecs += arch_gettimeoffset(); |
| 211 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 212 | } while (read_seqretry(&xtime_lock, seq)); |
| 213 | |
| 214 | timespec_add_ns(ts, nsecs); |
| 215 | } |
| 216 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 217 | EXPORT_SYMBOL(getnstimeofday); |
| 218 | |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 219 | ktime_t ktime_get(void) |
| 220 | { |
| 221 | cycle_t cycle_now, cycle_delta; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 222 | struct clocksource *clock; |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 223 | unsigned int seq; |
| 224 | s64 secs, nsecs; |
| 225 | |
| 226 | WARN_ON(timekeeping_suspended); |
| 227 | |
| 228 | do { |
| 229 | seq = read_seqbegin(&xtime_lock); |
| 230 | secs = xtime.tv_sec + wall_to_monotonic.tv_sec; |
| 231 | nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; |
| 232 | |
| 233 | /* read clocksource: */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 234 | clock = timekeeper.clock; |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 235 | cycle_now = clock->read(clock); |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 236 | |
| 237 | /* calculate the delta since the last update_wall_time: */ |
| 238 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| 239 | |
| 240 | /* convert to nanoseconds: */ |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 241 | nsecs += clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
| 242 | timekeeper.shift); |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 243 | |
| 244 | } while (read_seqretry(&xtime_lock, seq)); |
| 245 | /* |
| 246 | * Use ktime_set/ktime_add_ns to create a proper ktime on |
| 247 | * 32-bit architectures without CONFIG_KTIME_SCALAR. |
| 248 | */ |
| 249 | return ktime_add_ns(ktime_set(secs, 0), nsecs); |
| 250 | } |
| 251 | EXPORT_SYMBOL_GPL(ktime_get); |
| 252 | |
| 253 | /** |
| 254 | * ktime_get_ts - get the monotonic clock in timespec format |
| 255 | * @ts: pointer to timespec variable |
| 256 | * |
| 257 | * The function calculates the monotonic clock from the realtime |
| 258 | * clock and the wall_to_monotonic offset and stores the result |
| 259 | * in normalized timespec format in the variable pointed to by @ts. |
| 260 | */ |
| 261 | void ktime_get_ts(struct timespec *ts) |
| 262 | { |
| 263 | cycle_t cycle_now, cycle_delta; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 264 | struct clocksource *clock; |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 265 | struct timespec tomono; |
| 266 | unsigned int seq; |
| 267 | s64 nsecs; |
| 268 | |
| 269 | WARN_ON(timekeeping_suspended); |
| 270 | |
| 271 | do { |
| 272 | seq = read_seqbegin(&xtime_lock); |
| 273 | *ts = xtime; |
| 274 | tomono = wall_to_monotonic; |
| 275 | |
| 276 | /* read clocksource: */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 277 | clock = timekeeper.clock; |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 278 | cycle_now = clock->read(clock); |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 279 | |
| 280 | /* calculate the delta since the last update_wall_time: */ |
| 281 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| 282 | |
| 283 | /* convert to nanoseconds: */ |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 284 | nsecs = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
| 285 | timekeeper.shift); |
Martin Schwidefsky | 951ed4d | 2009-07-07 11:27:28 +0200 | [diff] [blame] | 286 | |
| 287 | } while (read_seqretry(&xtime_lock, seq)); |
| 288 | |
| 289 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, |
| 290 | ts->tv_nsec + tomono.tv_nsec + nsecs); |
| 291 | } |
| 292 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
| 293 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 294 | /** |
| 295 | * do_gettimeofday - Returns the time of day in a timeval |
| 296 | * @tv: pointer to the timeval to be set |
| 297 | * |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 298 | * NOTE: Users should be converted to using getnstimeofday() |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 299 | */ |
| 300 | void do_gettimeofday(struct timeval *tv) |
| 301 | { |
| 302 | struct timespec now; |
| 303 | |
Geert Uytterhoeven | efd9ac8 | 2008-01-30 13:30:01 +0100 | [diff] [blame] | 304 | getnstimeofday(&now); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 305 | tv->tv_sec = now.tv_sec; |
| 306 | tv->tv_usec = now.tv_nsec/1000; |
| 307 | } |
| 308 | |
| 309 | EXPORT_SYMBOL(do_gettimeofday); |
| 310 | /** |
| 311 | * do_settimeofday - Sets the time of day |
| 312 | * @tv: pointer to the timespec variable containing the new time |
| 313 | * |
| 314 | * Sets the time of day to the new time and update NTP and notify hrtimers |
| 315 | */ |
| 316 | int do_settimeofday(struct timespec *tv) |
| 317 | { |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 318 | struct timespec ts_delta; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 319 | unsigned long flags; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 320 | |
| 321 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 322 | return -EINVAL; |
| 323 | |
| 324 | write_seqlock_irqsave(&xtime_lock, flags); |
| 325 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 326 | timekeeping_forward_now(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 327 | |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 328 | ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec; |
| 329 | ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec; |
| 330 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 331 | |
Roman Zippel | 9a05511 | 2008-08-20 16:37:28 -0700 | [diff] [blame] | 332 | xtime = *tv; |
| 333 | |
Thomas Gleixner | 1001d0a | 2008-02-01 17:45:13 +0100 | [diff] [blame] | 334 | update_xtime_cache(0); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 335 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 336 | timekeeper.ntp_error = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 337 | ntp_clear(); |
| 338 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 339 | update_vsyscall(&xtime, timekeeper.clock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 340 | |
| 341 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 342 | |
| 343 | /* signal hrtimers about time change */ |
| 344 | clock_was_set(); |
| 345 | |
| 346 | return 0; |
| 347 | } |
| 348 | |
| 349 | EXPORT_SYMBOL(do_settimeofday); |
| 350 | |
| 351 | /** |
| 352 | * change_clocksource - Swaps clocksources if a new one is available |
| 353 | * |
| 354 | * Accumulates current time interval and initializes new clocksource |
| 355 | */ |
| 356 | static void change_clocksource(void) |
| 357 | { |
Magnus Damm | 4614e6a | 2009-04-21 12:24:02 -0700 | [diff] [blame] | 358 | struct clocksource *new, *old; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 359 | |
| 360 | new = clocksource_get_next(); |
| 361 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 362 | if (!new || timekeeper.clock == new) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 363 | return; |
| 364 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 365 | timekeeping_forward_now(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 366 | |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 367 | if (new->enable && !new->enable(new)) |
Magnus Damm | 4614e6a | 2009-04-21 12:24:02 -0700 | [diff] [blame] | 368 | return; |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 369 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 370 | old = timekeeper.clock; |
| 371 | timekeeper_setup_internals(new); |
| 372 | |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 373 | if (old->disable) |
| 374 | old->disable(old); |
Magnus Damm | 4614e6a | 2009-04-21 12:24:02 -0700 | [diff] [blame] | 375 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 376 | tick_clock_notify(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 377 | } |
Thomas Gleixner | a40f262 | 2009-07-07 13:00:31 +0200 | [diff] [blame] | 378 | #else /* GENERIC_TIME */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 379 | static inline void timekeeping_forward_now(void) { } |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 380 | static inline void change_clocksource(void) { } |
Thomas Gleixner | a40f262 | 2009-07-07 13:00:31 +0200 | [diff] [blame] | 381 | |
| 382 | /** |
| 383 | * ktime_get - get the monotonic time in ktime_t format |
| 384 | * |
| 385 | * returns the time in ktime_t format |
| 386 | */ |
| 387 | ktime_t ktime_get(void) |
| 388 | { |
| 389 | struct timespec now; |
| 390 | |
| 391 | ktime_get_ts(&now); |
| 392 | |
| 393 | return timespec_to_ktime(now); |
| 394 | } |
| 395 | EXPORT_SYMBOL_GPL(ktime_get); |
| 396 | |
| 397 | /** |
| 398 | * ktime_get_ts - get the monotonic clock in timespec format |
| 399 | * @ts: pointer to timespec variable |
| 400 | * |
| 401 | * The function calculates the monotonic clock from the realtime |
| 402 | * clock and the wall_to_monotonic offset and stores the result |
| 403 | * in normalized timespec format in the variable pointed to by @ts. |
| 404 | */ |
| 405 | void ktime_get_ts(struct timespec *ts) |
| 406 | { |
| 407 | struct timespec tomono; |
| 408 | unsigned long seq; |
| 409 | |
| 410 | do { |
| 411 | seq = read_seqbegin(&xtime_lock); |
| 412 | getnstimeofday(ts); |
| 413 | tomono = wall_to_monotonic; |
| 414 | |
| 415 | } while (read_seqretry(&xtime_lock, seq)); |
| 416 | |
| 417 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, |
| 418 | ts->tv_nsec + tomono.tv_nsec); |
| 419 | } |
| 420 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
| 421 | #endif /* !GENERIC_TIME */ |
| 422 | |
| 423 | /** |
| 424 | * ktime_get_real - get the real (wall-) time in ktime_t format |
| 425 | * |
| 426 | * returns the time in ktime_t format |
| 427 | */ |
| 428 | ktime_t ktime_get_real(void) |
| 429 | { |
| 430 | struct timespec now; |
| 431 | |
| 432 | getnstimeofday(&now); |
| 433 | |
| 434 | return timespec_to_ktime(now); |
| 435 | } |
| 436 | EXPORT_SYMBOL_GPL(ktime_get_real); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 437 | |
| 438 | /** |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 439 | * getrawmonotonic - Returns the raw monotonic time in a timespec |
| 440 | * @ts: pointer to the timespec to be set |
| 441 | * |
| 442 | * Returns the raw monotonic time (completely un-modified by ntp) |
| 443 | */ |
| 444 | void getrawmonotonic(struct timespec *ts) |
| 445 | { |
| 446 | unsigned long seq; |
| 447 | s64 nsecs; |
| 448 | cycle_t cycle_now, cycle_delta; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 449 | struct clocksource *clock; |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 450 | |
| 451 | do { |
| 452 | seq = read_seqbegin(&xtime_lock); |
| 453 | |
| 454 | /* read clocksource: */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 455 | clock = timekeeper.clock; |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 456 | cycle_now = clock->read(clock); |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 457 | |
| 458 | /* calculate the delta since the last update_wall_time: */ |
| 459 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| 460 | |
| 461 | /* convert to nanoseconds: */ |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 462 | nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 463 | clock->shift); |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 464 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 465 | *ts = raw_time; |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 466 | |
| 467 | } while (read_seqretry(&xtime_lock, seq)); |
| 468 | |
| 469 | timespec_add_ns(ts, nsecs); |
| 470 | } |
| 471 | EXPORT_SYMBOL(getrawmonotonic); |
| 472 | |
| 473 | |
| 474 | /** |
Li Zefan | cf4fc6c | 2008-02-08 04:19:24 -0800 | [diff] [blame] | 475 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 476 | */ |
Li Zefan | cf4fc6c | 2008-02-08 04:19:24 -0800 | [diff] [blame] | 477 | int timekeeping_valid_for_hres(void) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 478 | { |
| 479 | unsigned long seq; |
| 480 | int ret; |
| 481 | |
| 482 | do { |
| 483 | seq = read_seqbegin(&xtime_lock); |
| 484 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 485 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 486 | |
| 487 | } while (read_seqretry(&xtime_lock, seq)); |
| 488 | |
| 489 | return ret; |
| 490 | } |
| 491 | |
| 492 | /** |
| 493 | * read_persistent_clock - Return time in seconds from the persistent clock. |
| 494 | * |
| 495 | * Weak dummy function for arches that do not yet support it. |
| 496 | * Returns seconds from epoch using the battery backed persistent clock. |
| 497 | * Returns zero if unsupported. |
| 498 | * |
| 499 | * XXX - Do be sure to remove it once all arches implement it. |
| 500 | */ |
| 501 | unsigned long __attribute__((weak)) read_persistent_clock(void) |
| 502 | { |
| 503 | return 0; |
| 504 | } |
| 505 | |
| 506 | /* |
| 507 | * timekeeping_init - Initializes the clocksource and common timekeeping values |
| 508 | */ |
| 509 | void __init timekeeping_init(void) |
| 510 | { |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 511 | struct clocksource *clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 512 | unsigned long flags; |
| 513 | unsigned long sec = read_persistent_clock(); |
| 514 | |
| 515 | write_seqlock_irqsave(&xtime_lock, flags); |
| 516 | |
Roman Zippel | 7dffa3c | 2008-05-01 04:34:41 -0700 | [diff] [blame] | 517 | ntp_init(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 518 | |
Martin Schwidefsky | f1b8274 | 2009-08-14 15:47:21 +0200 | [diff] [blame] | 519 | clock = clocksource_default_clock(); |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 520 | if (clock->enable) |
| 521 | clock->enable(clock); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 522 | timekeeper_setup_internals(clock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 523 | |
| 524 | xtime.tv_sec = sec; |
| 525 | xtime.tv_nsec = 0; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 526 | raw_time.tv_sec = 0; |
| 527 | raw_time.tv_nsec = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 528 | set_normalized_timespec(&wall_to_monotonic, |
| 529 | -xtime.tv_sec, -xtime.tv_nsec); |
Thomas Gleixner | 1001d0a | 2008-02-01 17:45:13 +0100 | [diff] [blame] | 530 | update_xtime_cache(0); |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 531 | total_sleep_time = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 532 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 533 | } |
| 534 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 535 | /* time in seconds when suspend began */ |
| 536 | static unsigned long timekeeping_suspend_time; |
| 537 | |
| 538 | /** |
| 539 | * timekeeping_resume - Resumes the generic timekeeping subsystem. |
| 540 | * @dev: unused |
| 541 | * |
| 542 | * This is for the generic clocksource timekeeping. |
| 543 | * xtime/wall_to_monotonic/jiffies/etc are |
| 544 | * still managed by arch specific suspend/resume code. |
| 545 | */ |
| 546 | static int timekeeping_resume(struct sys_device *dev) |
| 547 | { |
| 548 | unsigned long flags; |
| 549 | unsigned long now = read_persistent_clock(); |
| 550 | |
Thomas Gleixner | d10ff3f | 2007-05-14 11:10:02 +0200 | [diff] [blame] | 551 | clocksource_resume(); |
| 552 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 553 | write_seqlock_irqsave(&xtime_lock, flags); |
| 554 | |
| 555 | if (now && (now > timekeeping_suspend_time)) { |
| 556 | unsigned long sleep_length = now - timekeeping_suspend_time; |
| 557 | |
| 558 | xtime.tv_sec += sleep_length; |
| 559 | wall_to_monotonic.tv_sec -= sleep_length; |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 560 | total_sleep_time += sleep_length; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 561 | } |
Thomas Gleixner | 1001d0a | 2008-02-01 17:45:13 +0100 | [diff] [blame] | 562 | update_xtime_cache(0); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 563 | /* re-base the last cycle value */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 564 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
| 565 | timekeeper.ntp_error = 0; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 566 | timekeeping_suspended = 0; |
| 567 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 568 | |
| 569 | touch_softlockup_watchdog(); |
| 570 | |
| 571 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); |
| 572 | |
| 573 | /* Resume hrtimers */ |
| 574 | hres_timers_resume(); |
| 575 | |
| 576 | return 0; |
| 577 | } |
| 578 | |
| 579 | static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) |
| 580 | { |
| 581 | unsigned long flags; |
| 582 | |
Thomas Gleixner | 3be9095 | 2007-09-16 15:36:43 +0200 | [diff] [blame] | 583 | timekeeping_suspend_time = read_persistent_clock(); |
| 584 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 585 | write_seqlock_irqsave(&xtime_lock, flags); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 586 | timekeeping_forward_now(); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 587 | timekeeping_suspended = 1; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 588 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 589 | |
| 590 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); |
| 591 | |
| 592 | return 0; |
| 593 | } |
| 594 | |
| 595 | /* sysfs resume/suspend bits for timekeeping */ |
| 596 | static struct sysdev_class timekeeping_sysclass = { |
Kay Sievers | af5ca3f | 2007-12-20 02:09:39 +0100 | [diff] [blame] | 597 | .name = "timekeeping", |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 598 | .resume = timekeeping_resume, |
| 599 | .suspend = timekeeping_suspend, |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 600 | }; |
| 601 | |
| 602 | static struct sys_device device_timer = { |
| 603 | .id = 0, |
| 604 | .cls = &timekeeping_sysclass, |
| 605 | }; |
| 606 | |
| 607 | static int __init timekeeping_init_device(void) |
| 608 | { |
| 609 | int error = sysdev_class_register(&timekeeping_sysclass); |
| 610 | if (!error) |
| 611 | error = sysdev_register(&device_timer); |
| 612 | return error; |
| 613 | } |
| 614 | |
| 615 | device_initcall(timekeeping_init_device); |
| 616 | |
| 617 | /* |
| 618 | * If the error is already larger, we look ahead even further |
| 619 | * to compensate for late or lost adjustments. |
| 620 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 621 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 622 | s64 *offset) |
| 623 | { |
| 624 | s64 tick_error, i; |
| 625 | u32 look_ahead, adj; |
| 626 | s32 error2, mult; |
| 627 | |
| 628 | /* |
| 629 | * Use the current error value to determine how much to look ahead. |
| 630 | * The larger the error the slower we adjust for it to avoid problems |
| 631 | * with losing too many ticks, otherwise we would overadjust and |
| 632 | * produce an even larger error. The smaller the adjustment the |
| 633 | * 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] | 634 | * 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] | 635 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
| 636 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 637 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 638 | error2 = abs(error2); |
| 639 | for (look_ahead = 0; error2 > 0; look_ahead++) |
| 640 | error2 >>= 2; |
| 641 | |
| 642 | /* |
| 643 | * Now calculate the error in (1 << look_ahead) ticks, but first |
| 644 | * remove the single look ahead already included in the error. |
| 645 | */ |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 646 | tick_error = tick_length >> (timekeeper.ntp_error_shift + 1); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 647 | tick_error -= timekeeper.xtime_interval >> 1; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 648 | error = ((error - tick_error) >> look_ahead) + tick_error; |
| 649 | |
| 650 | /* Finally calculate the adjustment shift value. */ |
| 651 | i = *interval; |
| 652 | mult = 1; |
| 653 | if (error < 0) { |
| 654 | error = -error; |
| 655 | *interval = -*interval; |
| 656 | *offset = -*offset; |
| 657 | mult = -1; |
| 658 | } |
| 659 | for (adj = 0; error > i; adj++) |
| 660 | error >>= 1; |
| 661 | |
| 662 | *interval <<= adj; |
| 663 | *offset <<= adj; |
| 664 | return mult << adj; |
| 665 | } |
| 666 | |
| 667 | /* |
| 668 | * Adjust the multiplier to reduce the error value, |
| 669 | * this is optimized for the most common adjustments of -1,0,1, |
| 670 | * for other values we can do a bit more work. |
| 671 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 672 | static void timekeeping_adjust(s64 offset) |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 673 | { |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 674 | s64 error, interval = timekeeper.cycle_interval; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 675 | int adj; |
| 676 | |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 677 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 678 | if (error > interval) { |
| 679 | error >>= 2; |
| 680 | if (likely(error <= interval)) |
| 681 | adj = 1; |
| 682 | else |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 683 | adj = timekeeping_bigadjust(error, &interval, &offset); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 684 | } else if (error < -interval) { |
| 685 | error >>= 2; |
| 686 | if (likely(error >= -interval)) { |
| 687 | adj = -1; |
| 688 | interval = -interval; |
| 689 | offset = -offset; |
| 690 | } else |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 691 | adj = timekeeping_bigadjust(error, &interval, &offset); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 692 | } else |
| 693 | return; |
| 694 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 695 | timekeeper.mult += adj; |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 696 | timekeeper.xtime_interval += interval; |
| 697 | timekeeper.xtime_nsec -= offset; |
| 698 | timekeeper.ntp_error -= (interval - offset) << |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 699 | timekeeper.ntp_error_shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 700 | } |
| 701 | |
| 702 | /** |
| 703 | * update_wall_time - Uses the current clocksource to increment the wall time |
| 704 | * |
| 705 | * Called from the timer interrupt, must hold a write on xtime_lock. |
| 706 | */ |
| 707 | void update_wall_time(void) |
| 708 | { |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 709 | struct clocksource *clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 710 | cycle_t offset; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 711 | u64 nsecs; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 712 | |
| 713 | /* Make sure we're fully resumed: */ |
| 714 | if (unlikely(timekeeping_suspended)) |
| 715 | return; |
| 716 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 717 | clock = timekeeper.clock; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 718 | #ifdef CONFIG_GENERIC_TIME |
Martin Schwidefsky | a0f7d48 | 2009-08-14 15:47:19 +0200 | [diff] [blame] | 719 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 720 | #else |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 721 | offset = timekeeper.cycle_interval; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 722 | #endif |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 723 | timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 724 | |
| 725 | /* normally this loop will run just once, however in the |
| 726 | * case of lost or late ticks, it will accumulate correctly. |
| 727 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 728 | while (offset >= timekeeper.cycle_interval) { |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 729 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 730 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 731 | /* accumulate one interval */ |
| 732 | offset -= timekeeper.cycle_interval; |
| 733 | clock->cycle_last += timekeeper.cycle_interval; |
| 734 | |
| 735 | timekeeper.xtime_nsec += timekeeper.xtime_interval; |
| 736 | if (timekeeper.xtime_nsec >= nsecps) { |
| 737 | timekeeper.xtime_nsec -= nsecps; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 738 | xtime.tv_sec++; |
| 739 | second_overflow(); |
| 740 | } |
| 741 | |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 742 | raw_time.tv_nsec += timekeeper.raw_interval; |
| 743 | if (raw_time.tv_nsec >= NSEC_PER_SEC) { |
| 744 | raw_time.tv_nsec -= NSEC_PER_SEC; |
| 745 | raw_time.tv_sec++; |
John Stultz | 2d42244 | 2008-08-20 16:37:30 -0700 | [diff] [blame] | 746 | } |
| 747 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 748 | /* accumulate error between NTP and clock interval */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 749 | timekeeper.ntp_error += tick_length; |
| 750 | timekeeper.ntp_error -= timekeeper.xtime_interval << |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 751 | timekeeper.ntp_error_shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 752 | } |
| 753 | |
| 754 | /* correct the clock when NTP error is too big */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 755 | timekeeping_adjust(offset); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 756 | |
john stultz | 6c9bacb | 2008-12-01 18:34:41 -0800 | [diff] [blame] | 757 | /* |
| 758 | * Since in the loop above, we accumulate any amount of time |
| 759 | * in xtime_nsec over a second into xtime.tv_sec, its possible for |
| 760 | * 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] | 761 | * slightly speeding the clocksource up in timekeeping_adjust(), |
john stultz | 6c9bacb | 2008-12-01 18:34:41 -0800 | [diff] [blame] | 762 | * its possible the required corrective factor to xtime_nsec could |
| 763 | * cause it to underflow. |
| 764 | * |
| 765 | * Now, we cannot simply roll the accumulated second back, since |
| 766 | * the NTP subsystem has been notified via second_overflow. So |
| 767 | * instead we push xtime_nsec forward by the amount we underflowed, |
| 768 | * and add that amount into the error. |
| 769 | * |
| 770 | * We'll correct this error next time through this function, when |
| 771 | * xtime_nsec is not as small. |
| 772 | */ |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 773 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
| 774 | s64 neg = -(s64)timekeeper.xtime_nsec; |
| 775 | timekeeper.xtime_nsec = 0; |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 776 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
john stultz | 6c9bacb | 2008-12-01 18:34:41 -0800 | [diff] [blame] | 777 | } |
| 778 | |
Roman Zippel | 5cd1c9c | 2008-09-22 14:42:43 -0700 | [diff] [blame] | 779 | /* store full nanoseconds into xtime after rounding it up and |
| 780 | * add the remainder to the error difference. |
| 781 | */ |
Martin Schwidefsky | 23ce721 | 2009-08-14 15:47:27 +0200 | [diff] [blame] | 782 | xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1; |
| 783 | timekeeper.xtime_nsec -= (s64) xtime.tv_nsec << timekeeper.shift; |
| 784 | timekeeper.ntp_error += timekeeper.xtime_nsec << |
| 785 | timekeeper.ntp_error_shift; |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 786 | |
Martin Schwidefsky | 0a54419 | 2009-08-14 15:47:28 +0200 | [diff] [blame^] | 787 | nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 788 | update_xtime_cache(nsecs); |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 789 | |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 790 | /* check to see if there is a new clocksource to use */ |
| 791 | change_clocksource(); |
Martin Schwidefsky | 155ec60 | 2009-08-14 15:47:26 +0200 | [diff] [blame] | 792 | update_vsyscall(&xtime, timekeeper.clock); |
john stultz | 8524070 | 2007-05-08 00:27:59 -0700 | [diff] [blame] | 793 | } |
Tomas Janousek | 7c3f1a5 | 2007-07-15 23:39:41 -0700 | [diff] [blame] | 794 | |
| 795 | /** |
| 796 | * getboottime - Return the real time of system boot. |
| 797 | * @ts: pointer to the timespec to be set |
| 798 | * |
| 799 | * Returns the time of day in a timespec. |
| 800 | * |
| 801 | * This is based on the wall_to_monotonic offset and the total suspend |
| 802 | * time. Calls to settimeofday will affect the value returned (which |
| 803 | * basically means that however wrong your real time clock is at boot time, |
| 804 | * you get the right time here). |
| 805 | */ |
| 806 | void getboottime(struct timespec *ts) |
| 807 | { |
| 808 | set_normalized_timespec(ts, |
| 809 | - (wall_to_monotonic.tv_sec + total_sleep_time), |
| 810 | - wall_to_monotonic.tv_nsec); |
| 811 | } |
| 812 | |
| 813 | /** |
| 814 | * monotonic_to_bootbased - Convert the monotonic time to boot based. |
| 815 | * @ts: pointer to the timespec to be converted |
| 816 | */ |
| 817 | void monotonic_to_bootbased(struct timespec *ts) |
| 818 | { |
| 819 | ts->tv_sec += total_sleep_time; |
| 820 | } |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 821 | |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 822 | unsigned long get_seconds(void) |
| 823 | { |
| 824 | return xtime_cache.tv_sec; |
| 825 | } |
| 826 | EXPORT_SYMBOL(get_seconds); |
| 827 | |
| 828 | |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 829 | struct timespec current_kernel_time(void) |
| 830 | { |
| 831 | struct timespec now; |
| 832 | unsigned long seq; |
| 833 | |
| 834 | do { |
| 835 | seq = read_seqbegin(&xtime_lock); |
| 836 | |
john stultz | 17c38b7 | 2007-07-24 18:38:34 -0700 | [diff] [blame] | 837 | now = xtime_cache; |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 838 | } while (read_seqretry(&xtime_lock, seq)); |
| 839 | |
| 840 | return now; |
| 841 | } |
john stultz | 2c6b47d | 2007-07-24 17:47:43 -0700 | [diff] [blame] | 842 | EXPORT_SYMBOL(current_kernel_time); |