arch/arm/kernel/time.c

   1 /*
   2  *  linux/arch/arm/kernel/time.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   5  *  Modifications for ARM (C) 1994-2001 Russell King
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  *  This file contains the ARM-specific time handling details:
  12  *  reading the RTC at bootup, etc...
  13  *
  14  *  1994-07-02  Alan Modra
  15  *              fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
  16  *  1998-12-20  Updated NTP code according to technical memorandum Jan '96
  17  *              "A Kernel Model for Precision Timekeeping" by Dave Mills
  18  */
  19 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/smp.h>
  25 #include <linux/timex.h>
  26 #include <linux/errno.h>
  27 #include <linux/profile.h>
  28 #include <linux/sysdev.h>
  29 #include <linux/timer.h>
  30 #include <linux/irq.h>
  31
  32 #include <asm/leds.h>
  33 #include <asm/thread_info.h>
  34 #include <asm/mach/time.h>
  35
  36 /*
  37  * Our system timer.
  38  */
  39 struct sys_timer *system_timer;
  40
  41 /* this needs a better home */
  42 DEFINE_SPINLOCK(rtc_lock);
  43
  44 #ifdef CONFIG_SA1100_RTC_MODULE
  45 EXPORT_SYMBOL(rtc_lock);
  46 #endif
  47
  48 /* change this if you have some constant time drift */
  49 #define USECS_PER_JIFFY (1000000/HZ)
  50
  51 #ifdef CONFIG_SMP
  52 unsigned long profile_pc(struct pt_regs *regs)
  53 {
  54         unsigned long fp, pc = instruction_pointer(regs);
  55
  56         if (in_lock_functions(pc)) {
  57                 fp = regs->ARM_fp;
  58                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  59         }
  60
  61         return pc;
  62 }
  63 EXPORT_SYMBOL(profile_pc);
  64 #endif
  65
  66 /*
  67  * hook for setting the RTC's idea of the current time.
  68  */
  69 int (*set_rtc)(void);
  70
  71 #ifndef CONFIG_GENERIC_TIME
  72 static unsigned long dummy_gettimeoffset(void)
  73 {
  74         return 0;
  75 }
  76 #endif
  77
  78 /*
  79  * Scheduler clock - returns current time in nanosec units.
  80  * This is the default implementation.  Sub-architecture
  81  * implementations can override this.
  82  */
  83 unsigned long long __attribute__((weak)) sched_clock(void)
  84 {
  85         return (unsigned long long)jiffies * (1000000000 / HZ);
  86 }
  87
  88 static unsigned long next_rtc_update;
  89
  90 /*
  91  * If we have an externally synchronized linux clock, then update
  92  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  93  * called as close as possible to 500 ms before the new second
  94  * starts.
  95  */
  96 static inline void do_set_rtc(void)
  97 {
  98         if (!ntp_synced() || set_rtc == NULL)
  99                 return;
 100
 101         if (next_rtc_update &&
 102             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 103                 return;
 104
 105         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 106             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 107                 return;
 108
 109         if (set_rtc())
 110                 /*
 111                  * rtc update failed.  Try again in 60s
 112                  */
 113                 next_rtc_update = xtime.tv_sec + 60;
 114         else
 115                 next_rtc_update = xtime.tv_sec + 660;
 116 }
 117
 118 #ifdef CONFIG_LEDS
 119
 120 static void dummy_leds_event(led_event_t evt)
 121 {
 122 }
 123
 124 void (*leds_event)(led_event_t) = dummy_leds_event;
 125
 126 struct leds_evt_name {
 127         const char      name[8];
 128         int             on;
 129         int             off;
 130 };
 131
 132 static const struct leds_evt_name evt_names[] = {
 133         { "amber", led_amber_on, led_amber_off },
 134         { "blue",  led_blue_on,  led_blue_off  },
 135         { "green", led_green_on, led_green_off },
 136         { "red",   led_red_on,   led_red_off   },
 137 };
 138
 139 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 140 {
 141         int ret = -EINVAL, len = strcspn(buf, " ");
 142
 143         if (len > 0 && buf[len] == '\0')
 144                 len--;
 145
 146         if (strncmp(buf, "claim", len) == 0) {
 147                 leds_event(led_claim);
 148                 ret = size;
 149         } else if (strncmp(buf, "release", len) == 0) {
 150                 leds_event(led_release);
 151                 ret = size;
 152         } else {
 153                 int i;
 154
 155                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 156                         if (strlen(evt_names[i].name) != len ||
 157                             strncmp(buf, evt_names[i].name, len) != 0)
 158                                 continue;
 159                         if (strncmp(buf+len, " on", 3) == 0) {
 160                                 leds_event(evt_names[i].on);
 161                                 ret = size;
 162                         } else if (strncmp(buf+len, " off", 4) == 0) {
 163                                 leds_event(evt_names[i].off);
 164                                 ret = size;
 165                         }
 166                         break;
 167                 }
 168         }
 169         return ret;
 170 }
 171
 172 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 173
 174 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 175 {
 176         leds_event(led_stop);
 177         return 0;
 178 }
 179
 180 static int leds_resume(struct sys_device *dev)
 181 {
 182         leds_event(led_start);
 183         return 0;
 184 }
 185
 186 static int leds_shutdown(struct sys_device *dev)
 187 {
 188         leds_event(led_halted);
 189         return 0;
 190 }
 191
 192 static struct sysdev_class leds_sysclass = {
 193         set_kset_name("leds"),
 194         .shutdown       = leds_shutdown,
 195         .suspend        = leds_suspend,
 196         .resume         = leds_resume,
 197 };
 198
 199 static struct sys_device leds_device = {
 200         .id             = 0,
 201         .cls            = &leds_sysclass,
 202 };
 203
 204 static int __init leds_init(void)
 205 {
 206         int ret;
 207         ret = sysdev_class_register(&leds_sysclass);
 208         if (ret == 0)
 209                 ret = sysdev_register(&leds_device);
 210         if (ret == 0)
 211                 ret = sysdev_create_file(&leds_device, &attr_event);
 212         return ret;
 213 }
 214
 215 device_initcall(leds_init);
 216
 217 EXPORT_SYMBOL(leds_event);
 218 #endif
 219
 220 #ifdef CONFIG_LEDS_TIMER
 221 static inline void do_leds(void)
 222 {
 223         static unsigned int count = HZ/2;
 224
 225         if (--count == 0) {
 226                 count = HZ/2;
 227                 leds_event(led_timer);
 228         }
 229 }
 230 #else
 231 #define do_leds()
 232 #endif
 233
 234 #ifndef CONFIG_GENERIC_TIME
 235 void do_gettimeofday(struct timeval *tv)
 236 {
 237         unsigned long flags;
 238         unsigned long seq;
 239         unsigned long usec, sec;
 240
 241         do {
 242                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 243                 usec = system_timer->offset();
 244                 sec = xtime.tv_sec;
 245                 usec += xtime.tv_nsec / 1000;
 246         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 247
 248         /* usec may have gone up a lot: be safe */
 249         while (usec >= 1000000) {
 250                 usec -= 1000000;
 251                 sec++;
 252         }
 253
 254         tv->tv_sec = sec;
 255         tv->tv_usec = usec;
 256 }
 257
 258 EXPORT_SYMBOL(do_gettimeofday);
 259
 260 int do_settimeofday(struct timespec *tv)
 261 {
 262         time_t wtm_sec, sec = tv->tv_sec;
 263         long wtm_nsec, nsec = tv->tv_nsec;
 264
 265         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 266                 return -EINVAL;
 267
 268         write_seqlock_irq(&xtime_lock);
 269         /*
 270          * This is revolting. We need to set "xtime" correctly. However, the
 271          * value in this location is the value at the most recent update of
 272          * wall time.  Discover what correction gettimeofday() would have
 273          * done, and then undo it!
 274          */
 275         nsec -= system_timer->offset() * NSEC_PER_USEC;
 276
 277         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 278         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 279
 280         set_normalized_timespec(&xtime, sec, nsec);
 281         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 282
 283         ntp_clear();
 284         write_sequnlock_irq(&xtime_lock);
 285         clock_was_set();
 286         return 0;
 287 }
 288
 289 EXPORT_SYMBOL(do_settimeofday);
 290 #endif /* !CONFIG_GENERIC_TIME */
 291
 292 /**
 293  * save_time_delta - Save the offset between system time and RTC time
 294  * @delta: pointer to timespec to store delta
 295  * @rtc: pointer to timespec for current RTC time
 296  *
 297  * Return a delta between the system time and the RTC time, such
 298  * that system time can be restored later with restore_time_delta()
 299  */
 300 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 301 {
 302         set_normalized_timespec(delta,
 303                                 xtime.tv_sec - rtc->tv_sec,
 304                                 xtime.tv_nsec - rtc->tv_nsec);
 305 }
 306 EXPORT_SYMBOL(save_time_delta);
 307
 308 /**
 309  * restore_time_delta - Restore the current system time
 310  * @delta: delta returned by save_time_delta()
 311  * @rtc: pointer to timespec for current RTC time
 312  */
 313 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 314 {
 315         struct timespec ts;
 316
 317         set_normalized_timespec(&ts,
 318                                 delta->tv_sec + rtc->tv_sec,
 319                                 delta->tv_nsec + rtc->tv_nsec);
 320
 321         do_settimeofday(&ts);
 322 }
 323 EXPORT_SYMBOL(restore_time_delta);
 324
 325 /*
 326  * Kernel system timer support.
 327  */
 328 void timer_tick(void)
 329 {
 330         profile_tick(CPU_PROFILING);
 331         do_leds();
 332         do_set_rtc();
 333         do_timer(1);
 334 #ifndef CONFIG_SMP
 335         update_process_times(user_mode(get_irq_regs()));
 336 #endif
 337 }
 338
 339 #ifdef CONFIG_PM
 340 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 341 {
 342         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 343
 344         if (timer->suspend != NULL)
 345                 timer->suspend();
 346
 347         return 0;
 348 }
 349
 350 static int timer_resume(struct sys_device *dev)
 351 {
 352         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 353
 354         if (timer->resume != NULL)
 355                 timer->resume();
 356
 357         return 0;
 358 }
 359 #else
 360 #define timer_suspend NULL
 361 #define timer_resume NULL
 362 #endif
 363
 364 static struct sysdev_class timer_sysclass = {
 365         set_kset_name("timer"),
 366         .suspend        = timer_suspend,
 367         .resume         = timer_resume,
 368 };
 369
 370 #ifdef CONFIG_NO_IDLE_HZ
 371 static int timer_dyn_tick_enable(void)
 372 {
 373         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 374         unsigned long flags;
 375         int ret = -ENODEV;
 376
 377         if (dyn_tick) {
 378                 spin_lock_irqsave(&dyn_tick->lock, flags);
 379                 ret = 0;
 380                 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
 381                         ret = dyn_tick->enable();
 382
 383                         if (ret == 0)
 384                                 dyn_tick->state |= DYN_TICK_ENABLED;
 385                 }
 386                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 387         }
 388
 389         return ret;
 390 }
 391
 392 static int timer_dyn_tick_disable(void)
 393 {
 394         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 395         unsigned long flags;
 396         int ret = -ENODEV;
 397
 398         if (dyn_tick) {
 399                 spin_lock_irqsave(&dyn_tick->lock, flags);
 400                 ret = 0;
 401                 if (dyn_tick->state & DYN_TICK_ENABLED) {
 402                         ret = dyn_tick->disable();
 403
 404                         if (ret == 0)
 405                                 dyn_tick->state &= ~DYN_TICK_ENABLED;
 406                 }
 407                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 408         }
 409
 410         return ret;
 411 }
 412
 413 /*
 414  * Reprogram the system timer for at least the calculated time interval.
 415  * This function should be called from the idle thread with IRQs disabled,
 416  * immediately before sleeping.
 417  */
 418 void timer_dyn_reprogram(void)
 419 {
 420         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 421         unsigned long next, seq, flags;
 422
 423         if (!dyn_tick)
 424                 return;
 425
 426         spin_lock_irqsave(&dyn_tick->lock, flags);
 427         if (dyn_tick->state & DYN_TICK_ENABLED) {
 428                 next = next_timer_interrupt();
 429                 do {
 430                         seq = read_seqbegin(&xtime_lock);
 431                         dyn_tick->reprogram(next - jiffies);
 432                 } while (read_seqretry(&xtime_lock, seq));
 433         }
 434         spin_unlock_irqrestore(&dyn_tick->lock, flags);
 435 }
 436
 437 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
 438 {
 439         return sprintf(buf, "%i\n",
 440                        (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
 441 }
 442
 443 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
 444                                   size_t count)
 445 {
 446         unsigned int enable = simple_strtoul(buf, NULL, 2);
 447
 448         if (enable)
 449                 timer_dyn_tick_enable();
 450         else
 451                 timer_dyn_tick_disable();
 452
 453         return count;
 454 }
 455 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
 456
 457 /*
 458  * dyntick=enable|disable
 459  */
 460 static char dyntick_str[4] __initdata = "";
 461
 462 static int __init dyntick_setup(char *str)
 463 {
 464         if (str)
 465                 strlcpy(dyntick_str, str, sizeof(dyntick_str));
 466         return 1;
 467 }
 468
 469 __setup("dyntick=", dyntick_setup);
 470 #endif
 471
 472 static int __init timer_init_sysfs(void)
 473 {
 474         int ret = sysdev_class_register(&timer_sysclass);
 475         if (ret == 0) {
 476                 system_timer->dev.cls = &timer_sysclass;
 477                 ret = sysdev_register(&system_timer->dev);
 478         }
 479
 480 #ifdef CONFIG_NO_IDLE_HZ
 481         if (ret == 0 && system_timer->dyn_tick) {
 482                 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
 483
 484                 /*
 485                  * Turn on dynamic tick after calibrate delay
 486                  * for correct bogomips
 487                  */
 488                 if (ret == 0 && dyntick_str[0] == 'e')
 489                         ret = timer_dyn_tick_enable();
 490         }
 491 #endif
 492
 493         return ret;
 494 }
 495
 496 device_initcall(timer_init_sysfs);
 497
 498 void __init time_init(void)
 499 {
 500 #ifndef CONFIG_GENERIC_TIME
 501         if (system_timer->offset == NULL)
 502                 system_timer->offset = dummy_gettimeoffset;
 503 #endif
 504         system_timer->init();
 505
 506 #ifdef CONFIG_NO_IDLE_HZ
 507         if (system_timer->dyn_tick)
 508                 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
 509 #endif
 510 }
 511