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/config.h>
  20 #include <linux/module.h>
  21 #include <linux/kernel.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/time.h>
  24 #include <linux/init.h>
  25 #include <linux/smp.h>
  26 #include <linux/timex.h>
  27 #include <linux/errno.h>
  28 #include <linux/profile.h>
  29 #include <linux/sysdev.h>
  30 #include <linux/timer.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 extern unsigned long wall_jiffies;
  42
  43 /* this needs a better home */
  44 DEFINE_SPINLOCK(rtc_lock);
  45
  46 #ifdef CONFIG_SA1100_RTC_MODULE
  47 EXPORT_SYMBOL(rtc_lock);
  48 #endif
  49
  50 /* change this if you have some constant time drift */
  51 #define USECS_PER_JIFFY (1000000/HZ)
  52
  53 #ifdef CONFIG_SMP
  54 unsigned long profile_pc(struct pt_regs *regs)
  55 {
  56         unsigned long fp, pc = instruction_pointer(regs);
  57
  58         if (in_lock_functions(pc)) {
  59                 fp = regs->ARM_fp;
  60                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  61         }
  62
  63         return pc;
  64 }
  65 EXPORT_SYMBOL(profile_pc);
  66 #endif
  67
  68 /*
  69  * hook for setting the RTC's idea of the current time.
  70  */
  71 int (*set_rtc)(void);
  72
  73 static unsigned long dummy_gettimeoffset(void)
  74 {
  75         return 0;
  76 }
  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 = 50;
 224
 225         if (--count == 0) {
 226                 count = 50;
 227                 leds_event(led_timer);
 228         }
 229 }
 230 #else
 231 #define do_leds()
 232 #endif
 233
 234 void do_gettimeofday(struct timeval *tv)
 235 {
 236         unsigned long flags;
 237         unsigned long seq;
 238         unsigned long usec, sec, lost;
 239
 240         do {
 241                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 242                 usec = system_timer->offset();
 243
 244                 lost = jiffies - wall_jiffies;
 245                 if (lost)
 246                         usec += lost * USECS_PER_JIFFY;
 247
 248                 sec = xtime.tv_sec;
 249                 usec += xtime.tv_nsec / 1000;
 250         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 251
 252         /* usec may have gone up a lot: be safe */
 253         while (usec >= 1000000) {
 254                 usec -= 1000000;
 255                 sec++;
 256         }
 257
 258         tv->tv_sec = sec;
 259         tv->tv_usec = usec;
 260 }
 261
 262 EXPORT_SYMBOL(do_gettimeofday);
 263
 264 int do_settimeofday(struct timespec *tv)
 265 {
 266         time_t wtm_sec, sec = tv->tv_sec;
 267         long wtm_nsec, nsec = tv->tv_nsec;
 268
 269         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 270                 return -EINVAL;
 271
 272         write_seqlock_irq(&xtime_lock);
 273         /*
 274          * This is revolting. We need to set "xtime" correctly. However, the
 275          * value in this location is the value at the most recent update of
 276          * wall time.  Discover what correction gettimeofday() would have
 277          * done, and then undo it!
 278          */
 279         nsec -= system_timer->offset() * NSEC_PER_USEC;
 280         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 281
 282         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 283         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 284
 285         set_normalized_timespec(&xtime, sec, nsec);
 286         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 287
 288         ntp_clear();
 289         write_sequnlock_irq(&xtime_lock);
 290         clock_was_set();
 291         return 0;
 292 }
 293
 294 EXPORT_SYMBOL(do_settimeofday);
 295
 296 /**
 297  * save_time_delta - Save the offset between system time and RTC time
 298  * @delta: pointer to timespec to store delta
 299  * @rtc: pointer to timespec for current RTC time
 300  *
 301  * Return a delta between the system time and the RTC time, such
 302  * that system time can be restored later with restore_time_delta()
 303  */
 304 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 305 {
 306         set_normalized_timespec(delta,
 307                                 xtime.tv_sec - rtc->tv_sec,
 308                                 xtime.tv_nsec - rtc->tv_nsec);
 309 }
 310 EXPORT_SYMBOL(save_time_delta);
 311
 312 /**
 313  * restore_time_delta - Restore the current system time
 314  * @delta: delta returned by save_time_delta()
 315  * @rtc: pointer to timespec for current RTC time
 316  */
 317 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 318 {
 319         struct timespec ts;
 320
 321         set_normalized_timespec(&ts,
 322                                 delta->tv_sec + rtc->tv_sec,
 323                                 delta->tv_nsec + rtc->tv_nsec);
 324
 325         do_settimeofday(&ts);
 326 }
 327 EXPORT_SYMBOL(restore_time_delta);
 328
 329 /*
 330  * Kernel system timer support.
 331  */
 332 void timer_tick(struct pt_regs *regs)
 333 {
 334         profile_tick(CPU_PROFILING, regs);
 335         do_leds();
 336         do_set_rtc();
 337         do_timer(regs);
 338 #ifndef CONFIG_SMP
 339         update_process_times(user_mode(regs));
 340 #endif
 341 }
 342
 343 #ifdef CONFIG_PM
 344 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 345 {
 346         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 347
 348         if (timer->suspend != NULL)
 349                 timer->suspend();
 350
 351         return 0;
 352 }
 353
 354 static int timer_resume(struct sys_device *dev)
 355 {
 356         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 357
 358         if (timer->resume != NULL)
 359                 timer->resume();
 360
 361         return 0;
 362 }
 363 #else
 364 #define timer_suspend NULL
 365 #define timer_resume NULL
 366 #endif
 367
 368 static struct sysdev_class timer_sysclass = {
 369         set_kset_name("timer"),
 370         .suspend        = timer_suspend,
 371         .resume         = timer_resume,
 372 };
 373
 374 #ifdef CONFIG_NO_IDLE_HZ
 375 static int timer_dyn_tick_enable(void)
 376 {
 377         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 378         unsigned long flags;
 379         int ret = -ENODEV;
 380
 381         if (dyn_tick) {
 382                 spin_lock_irqsave(&dyn_tick->lock, flags);
 383                 ret = 0;
 384                 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
 385                         ret = dyn_tick->enable();
 386
 387                         if (ret == 0)
 388                                 dyn_tick->state |= DYN_TICK_ENABLED;
 389                 }
 390                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 391         }
 392
 393         return ret;
 394 }
 395
 396 static int timer_dyn_tick_disable(void)
 397 {
 398         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 399         unsigned long flags;
 400         int ret = -ENODEV;
 401
 402         if (dyn_tick) {
 403                 spin_lock_irqsave(&dyn_tick->lock, flags);
 404                 ret = 0;
 405                 if (dyn_tick->state & DYN_TICK_ENABLED) {
 406                         ret = dyn_tick->disable();
 407
 408                         if (ret == 0)
 409                                 dyn_tick->state &= ~DYN_TICK_ENABLED;
 410                 }
 411                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 412         }
 413
 414         return ret;
 415 }
 416
 417 /*
 418  * Reprogram the system timer for at least the calculated time interval.
 419  * This function should be called from the idle thread with IRQs disabled,
 420  * immediately before sleeping.
 421  */
 422 void timer_dyn_reprogram(void)
 423 {
 424         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 425         unsigned long next, seq, flags;
 426
 427         if (!dyn_tick)
 428                 return;
 429
 430         spin_lock_irqsave(&dyn_tick->lock, flags);
 431         if (dyn_tick->state & DYN_TICK_ENABLED) {
 432                 next = next_timer_interrupt();
 433                 do {
 434                         seq = read_seqbegin(&xtime_lock);
 435                         dyn_tick->reprogram(next - jiffies);
 436                 } while (read_seqretry(&xtime_lock, seq));
 437         }
 438         spin_unlock_irqrestore(&dyn_tick->lock, flags);
 439 }
 440
 441 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
 442 {
 443         return sprintf(buf, "%i\n",
 444                        (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
 445 }
 446
 447 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
 448                                   size_t count)
 449 {
 450         unsigned int enable = simple_strtoul(buf, NULL, 2);
 451
 452         if (enable)
 453                 timer_dyn_tick_enable();
 454         else
 455                 timer_dyn_tick_disable();
 456
 457         return count;
 458 }
 459 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
 460
 461 /*
 462  * dyntick=enable|disable
 463  */
 464 static char dyntick_str[4] __initdata = "";
 465
 466 static int __init dyntick_setup(char *str)
 467 {
 468         if (str)
 469                 strlcpy(dyntick_str, str, sizeof(dyntick_str));
 470         return 1;
 471 }
 472
 473 __setup("dyntick=", dyntick_setup);
 474 #endif
 475
 476 static int __init timer_init_sysfs(void)
 477 {
 478         int ret = sysdev_class_register(&timer_sysclass);
 479         if (ret == 0) {
 480                 system_timer->dev.cls = &timer_sysclass;
 481                 ret = sysdev_register(&system_timer->dev);
 482         }
 483
 484 #ifdef CONFIG_NO_IDLE_HZ
 485         if (ret == 0 && system_timer->dyn_tick) {
 486                 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
 487
 488                 /*
 489                  * Turn on dynamic tick after calibrate delay
 490                  * for correct bogomips
 491                  */
 492                 if (ret == 0 && dyntick_str[0] == 'e')
 493                         ret = timer_dyn_tick_enable();
 494         }
 495 #endif
 496
 497         return ret;
 498 }
 499
 500 device_initcall(timer_init_sysfs);
 501
 502 void __init time_init(void)
 503 {
 504         if (system_timer->offset == NULL)
 505                 system_timer->offset = dummy_gettimeoffset;
 506         system_timer->init();
 507
 508 #ifdef CONFIG_NO_IDLE_HZ
 509         if (system_timer->dyn_tick)
 510                 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
 511 #endif
 512 }
 513