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
  31 #include <asm/leds.h>
  32 #include <asm/thread_info.h>
  33 #include <asm/mach/time.h>
  34
  35 /*
  36  * Our system timer.
  37  */
  38 struct sys_timer *system_timer;
  39
  40 extern unsigned long wall_jiffies;
  41
  42 /* this needs a better home */
  43 DEFINE_SPINLOCK(rtc_lock);
  44
  45 #ifdef CONFIG_SA1100_RTC_MODULE
  46 EXPORT_SYMBOL(rtc_lock);
  47 #endif
  48
  49 /* change this if you have some constant time drift */
  50 #define USECS_PER_JIFFY (1000000/HZ)
  51
  52 #ifdef CONFIG_SMP
  53 unsigned long profile_pc(struct pt_regs *regs)
  54 {
  55         unsigned long fp, pc = instruction_pointer(regs);
  56
  57         if (in_lock_functions(pc)) {
  58                 fp = regs->ARM_fp;
  59                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  60         }
  61
  62         return pc;
  63 }
  64 EXPORT_SYMBOL(profile_pc);
  65 #endif
  66
  67 /*
  68  * hook for setting the RTC's idea of the current time.
  69  */
  70 int (*set_rtc)(void);
  71
  72 #ifndef CONFIG_GENERIC_TIME
  73 static unsigned long dummy_gettimeoffset(void)
  74 {
  75         return 0;
  76 }
  77 #endif
  78
  79 /*
  80  * Scheduler clock - returns current time in nanosec units.
  81  * This is the default implementation.  Sub-architecture
  82  * implementations can override this.
  83  */
  84 unsigned long long __attribute__((weak)) sched_clock(void)
  85 {
  86         return (unsigned long long)jiffies * (1000000000 / HZ);
  87 }
  88
  89 static unsigned long next_rtc_update;
  90
  91 /*
  92  * If we have an externally synchronized linux clock, then update
  93  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  94  * called as close as possible to 500 ms before the new second
  95  * starts.
  96  */
  97 static inline void do_set_rtc(void)
  98 {
  99         if (!ntp_synced() || set_rtc == NULL)
 100                 return;
 101
 102         if (next_rtc_update &&
 103             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 104                 return;
 105
 106         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 107             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 108                 return;
 109
 110         if (set_rtc())
 111                 /*
 112                  * rtc update failed.  Try again in 60s
 113                  */
 114                 next_rtc_update = xtime.tv_sec + 60;
 115         else
 116                 next_rtc_update = xtime.tv_sec + 660;
 117 }
 118
 119 #ifdef CONFIG_LEDS
 120
 121 static void dummy_leds_event(led_event_t evt)
 122 {
 123 }
 124
 125 void (*leds_event)(led_event_t) = dummy_leds_event;
 126
 127 struct leds_evt_name {
 128         const char      name[8];
 129         int             on;
 130         int             off;
 131 };
 132
 133 static const struct leds_evt_name evt_names[] = {
 134         { "amber", led_amber_on, led_amber_off },
 135         { "blue",  led_blue_on,  led_blue_off  },
 136         { "green", led_green_on, led_green_off },
 137         { "red",   led_red_on,   led_red_off   },
 138 };
 139
 140 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 141 {
 142         int ret = -EINVAL, len = strcspn(buf, " ");
 143
 144         if (len > 0 && buf[len] == '\0')
 145                 len--;
 146
 147         if (strncmp(buf, "claim", len) == 0) {
 148                 leds_event(led_claim);
 149                 ret = size;
 150         } else if (strncmp(buf, "release", len) == 0) {
 151                 leds_event(led_release);
 152                 ret = size;
 153         } else {
 154                 int i;
 155
 156                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 157                         if (strlen(evt_names[i].name) != len ||
 158                             strncmp(buf, evt_names[i].name, len) != 0)
 159                                 continue;
 160                         if (strncmp(buf+len, " on", 3) == 0) {
 161                                 leds_event(evt_names[i].on);
 162                                 ret = size;
 163                         } else if (strncmp(buf+len, " off", 4) == 0) {
 164                                 leds_event(evt_names[i].off);
 165                                 ret = size;
 166                         }
 167                         break;
 168                 }
 169         }
 170         return ret;
 171 }
 172
 173 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 174
 175 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 176 {
 177         leds_event(led_stop);
 178         return 0;
 179 }
 180
 181 static int leds_resume(struct sys_device *dev)
 182 {
 183         leds_event(led_start);
 184         return 0;
 185 }
 186
 187 static int leds_shutdown(struct sys_device *dev)
 188 {
 189         leds_event(led_halted);
 190         return 0;
 191 }
 192
 193 static struct sysdev_class leds_sysclass = {
 194         set_kset_name("leds"),
 195         .shutdown       = leds_shutdown,
 196         .suspend        = leds_suspend,
 197         .resume         = leds_resume,
 198 };
 199
 200 static struct sys_device leds_device = {
 201         .id             = 0,
 202         .cls            = &leds_sysclass,
 203 };
 204
 205 static int __init leds_init(void)
 206 {
 207         int ret;
 208         ret = sysdev_class_register(&leds_sysclass);
 209         if (ret == 0)
 210                 ret = sysdev_register(&leds_device);
 211         if (ret == 0)
 212                 ret = sysdev_create_file(&leds_device, &attr_event);
 213         return ret;
 214 }
 215
 216 device_initcall(leds_init);
 217
 218 EXPORT_SYMBOL(leds_event);
 219 #endif
 220
 221 #ifdef CONFIG_LEDS_TIMER
 222 static inline void do_leds(void)
 223 {
 224         static unsigned int count = 50;
 225
 226         if (--count == 0) {
 227                 count = 50;
 228                 leds_event(led_timer);
 229         }
 230 }
 231 #else
 232 #define do_leds()
 233 #endif
 234
 235 #ifndef CONFIG_GENERIC_TIME
 236 void do_gettimeofday(struct timeval *tv)
 237 {
 238         unsigned long flags;
 239         unsigned long seq;
 240         unsigned long usec, sec, lost;
 241
 242         do {
 243                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 244                 usec = system_timer->offset();
 245
 246                 lost = jiffies - wall_jiffies;
 247                 if (lost)
 248                         usec += lost * USECS_PER_JIFFY;
 249
 250                 sec = xtime.tv_sec;
 251                 usec += xtime.tv_nsec / 1000;
 252         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 253
 254         /* usec may have gone up a lot: be safe */
 255         while (usec >= 1000000) {
 256                 usec -= 1000000;
 257                 sec++;
 258         }
 259
 260         tv->tv_sec = sec;
 261         tv->tv_usec = usec;
 262 }
 263
 264 EXPORT_SYMBOL(do_gettimeofday);
 265
 266 int do_settimeofday(struct timespec *tv)
 267 {
 268         time_t wtm_sec, sec = tv->tv_sec;
 269         long wtm_nsec, nsec = tv->tv_nsec;
 270
 271         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 272                 return -EINVAL;
 273
 274         write_seqlock_irq(&xtime_lock);
 275         /*
 276          * This is revolting. We need to set "xtime" correctly. However, the
 277          * value in this location is the value at the most recent update of
 278          * wall time.  Discover what correction gettimeofday() would have
 279          * done, and then undo it!
 280          */
 281         nsec -= system_timer->offset() * NSEC_PER_USEC;
 282         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 283
 284         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 285         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 286
 287         set_normalized_timespec(&xtime, sec, nsec);
 288         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 289
 290         ntp_clear();
 291         write_sequnlock_irq(&xtime_lock);
 292         clock_was_set();
 293         return 0;
 294 }
 295
 296 EXPORT_SYMBOL(do_settimeofday);
 297 #endif /* !CONFIG_GENERIC_TIME */
 298
 299 /**
 300  * save_time_delta - Save the offset between system time and RTC time
 301  * @delta: pointer to timespec to store delta
 302  * @rtc: pointer to timespec for current RTC time
 303  *
 304  * Return a delta between the system time and the RTC time, such
 305  * that system time can be restored later with restore_time_delta()
 306  */
 307 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 308 {
 309         set_normalized_timespec(delta,
 310                                 xtime.tv_sec - rtc->tv_sec,
 311                                 xtime.tv_nsec - rtc->tv_nsec);
 312 }
 313 EXPORT_SYMBOL(save_time_delta);
 314
 315 /**
 316  * restore_time_delta - Restore the current system time
 317  * @delta: delta returned by save_time_delta()
 318  * @rtc: pointer to timespec for current RTC time
 319  */
 320 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 321 {
 322         struct timespec ts;
 323
 324         set_normalized_timespec(&ts,
 325                                 delta->tv_sec + rtc->tv_sec,
 326                                 delta->tv_nsec + rtc->tv_nsec);
 327
 328         do_settimeofday(&ts);
 329 }
 330 EXPORT_SYMBOL(restore_time_delta);
 331
 332 /*
 333  * Kernel system timer support.
 334  */
 335 void timer_tick(struct pt_regs *regs)
 336 {
 337         profile_tick(CPU_PROFILING, regs);
 338         do_leds();
 339         do_set_rtc();
 340         do_timer(regs);
 341 #ifndef CONFIG_SMP
 342         update_process_times(user_mode(regs));
 343 #endif
 344 }
 345
 346 #ifdef CONFIG_PM
 347 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 348 {
 349         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 350
 351         if (timer->suspend != NULL)
 352                 timer->suspend();
 353
 354         return 0;
 355 }
 356
 357 static int timer_resume(struct sys_device *dev)
 358 {
 359         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 360
 361         if (timer->resume != NULL)
 362                 timer->resume();
 363
 364         return 0;
 365 }
 366 #else
 367 #define timer_suspend NULL
 368 #define timer_resume NULL
 369 #endif
 370
 371 static struct sysdev_class timer_sysclass = {
 372         set_kset_name("timer"),
 373         .suspend        = timer_suspend,
 374         .resume         = timer_resume,
 375 };
 376
 377 #ifdef CONFIG_NO_IDLE_HZ
 378 static int timer_dyn_tick_enable(void)
 379 {
 380         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 381         unsigned long flags;
 382         int ret = -ENODEV;
 383
 384         if (dyn_tick) {
 385                 spin_lock_irqsave(&dyn_tick->lock, flags);
 386                 ret = 0;
 387                 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
 388                         ret = dyn_tick->enable();
 389
 390                         if (ret == 0)
 391                                 dyn_tick->state |= DYN_TICK_ENABLED;
 392                 }
 393                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 394         }
 395
 396         return ret;
 397 }
 398
 399 static int timer_dyn_tick_disable(void)
 400 {
 401         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 402         unsigned long flags;
 403         int ret = -ENODEV;
 404
 405         if (dyn_tick) {
 406                 spin_lock_irqsave(&dyn_tick->lock, flags);
 407                 ret = 0;
 408                 if (dyn_tick->state & DYN_TICK_ENABLED) {
 409                         ret = dyn_tick->disable();
 410
 411                         if (ret == 0)
 412                                 dyn_tick->state &= ~DYN_TICK_ENABLED;
 413                 }
 414                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 415         }
 416
 417         return ret;
 418 }
 419
 420 /*
 421  * Reprogram the system timer for at least the calculated time interval.
 422  * This function should be called from the idle thread with IRQs disabled,
 423  * immediately before sleeping.
 424  */
 425 void timer_dyn_reprogram(void)
 426 {
 427         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 428         unsigned long next, seq, flags;
 429
 430         if (!dyn_tick)
 431                 return;
 432
 433         spin_lock_irqsave(&dyn_tick->lock, flags);
 434         if (dyn_tick->state & DYN_TICK_ENABLED) {
 435                 next = next_timer_interrupt();
 436                 do {
 437                         seq = read_seqbegin(&xtime_lock);
 438                         dyn_tick->reprogram(next - jiffies);
 439                 } while (read_seqretry(&xtime_lock, seq));
 440         }
 441         spin_unlock_irqrestore(&dyn_tick->lock, flags);
 442 }
 443
 444 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
 445 {
 446         return sprintf(buf, "%i\n",
 447                        (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
 448 }
 449
 450 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
 451                                   size_t count)
 452 {
 453         unsigned int enable = simple_strtoul(buf, NULL, 2);
 454
 455         if (enable)
 456                 timer_dyn_tick_enable();
 457         else
 458                 timer_dyn_tick_disable();
 459
 460         return count;
 461 }
 462 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
 463
 464 /*
 465  * dyntick=enable|disable
 466  */
 467 static char dyntick_str[4] __initdata = "";
 468
 469 static int __init dyntick_setup(char *str)
 470 {
 471         if (str)
 472                 strlcpy(dyntick_str, str, sizeof(dyntick_str));
 473         return 1;
 474 }
 475
 476 __setup("dyntick=", dyntick_setup);
 477 #endif
 478
 479 static int __init timer_init_sysfs(void)
 480 {
 481         int ret = sysdev_class_register(&timer_sysclass);
 482         if (ret == 0) {
 483                 system_timer->dev.cls = &timer_sysclass;
 484                 ret = sysdev_register(&system_timer->dev);
 485         }
 486
 487 #ifdef CONFIG_NO_IDLE_HZ
 488         if (ret == 0 && system_timer->dyn_tick) {
 489                 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
 490
 491                 /*
 492                  * Turn on dynamic tick after calibrate delay
 493                  * for correct bogomips
 494                  */
 495                 if (ret == 0 && dyntick_str[0] == 'e')
 496                         ret = timer_dyn_tick_enable();
 497         }
 498 #endif
 499
 500         return ret;
 501 }
 502
 503 device_initcall(timer_init_sysfs);
 504
 505 void __init time_init(void)
 506 {
 507 #ifndef CONFIG_GENERIC_TIME
 508         if (system_timer->offset == NULL)
 509                 system_timer->offset = dummy_gettimeoffset;
 510 #endif
 511         system_timer->init();
 512
 513 #ifdef CONFIG_NO_IDLE_HZ
 514         if (system_timer->dyn_tick)
 515                 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
 516 #endif
 517 }
 518