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 <linux/mc146818rtc.h>
  33
  34 #include <asm/leds.h>
  35 #include <asm/thread_info.h>
  36 #include <asm/mach/time.h>
  37
  38 /*
  39  * Our system timer.
  40  */
  41 struct sys_timer *system_timer;
  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 #ifndef CONFIG_GENERIC_TIME
  74 static unsigned long dummy_gettimeoffset(void)
  75 {
  76         return 0;
  77 }
  78 #endif
  79
  80 /*
  81  * Scheduler clock - returns current time in nanosec units.
  82  * This is the default implementation.  Sub-architecture
  83  * implementations can override this.
  84  */
  85 unsigned long long __attribute__((weak)) sched_clock(void)
  86 {
  87         return (unsigned long long)jiffies * (1000000000 / HZ);
  88 }
  89
  90 static unsigned long next_rtc_update;
  91
  92 /*
  93  * If we have an externally synchronized linux clock, then update
  94  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  95  * called as close as possible to 500 ms before the new second
  96  * starts.
  97  */
  98 static inline void do_set_rtc(void)
  99 {
 100         if (!ntp_synced() || set_rtc == NULL)
 101                 return;
 102
 103         if (next_rtc_update &&
 104             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 105                 return;
 106
 107         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 108             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 109                 return;
 110
 111         if (set_rtc())
 112                 /*
 113                  * rtc update failed.  Try again in 60s
 114                  */
 115                 next_rtc_update = xtime.tv_sec + 60;
 116         else
 117                 next_rtc_update = xtime.tv_sec + 660;
 118 }
 119
 120 #ifdef CONFIG_LEDS
 121
 122 static void dummy_leds_event(led_event_t evt)
 123 {
 124 }
 125
 126 void (*leds_event)(led_event_t) = dummy_leds_event;
 127
 128 struct leds_evt_name {
 129         const char      name[8];
 130         int             on;
 131         int             off;
 132 };
 133
 134 static const struct leds_evt_name evt_names[] = {
 135         { "amber", led_amber_on, led_amber_off },
 136         { "blue",  led_blue_on,  led_blue_off  },
 137         { "green", led_green_on, led_green_off },
 138         { "red",   led_red_on,   led_red_off   },
 139 };
 140
 141 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 142 {
 143         int ret = -EINVAL, len = strcspn(buf, " ");
 144
 145         if (len > 0 && buf[len] == '\0')
 146                 len--;
 147
 148         if (strncmp(buf, "claim", len) == 0) {
 149                 leds_event(led_claim);
 150                 ret = size;
 151         } else if (strncmp(buf, "release", len) == 0) {
 152                 leds_event(led_release);
 153                 ret = size;
 154         } else {
 155                 int i;
 156
 157                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 158                         if (strlen(evt_names[i].name) != len ||
 159                             strncmp(buf, evt_names[i].name, len) != 0)
 160                                 continue;
 161                         if (strncmp(buf+len, " on", 3) == 0) {
 162                                 leds_event(evt_names[i].on);
 163                                 ret = size;
 164                         } else if (strncmp(buf+len, " off", 4) == 0) {
 165                                 leds_event(evt_names[i].off);
 166                                 ret = size;
 167                         }
 168                         break;
 169                 }
 170         }
 171         return ret;
 172 }
 173
 174 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 175
 176 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 177 {
 178         leds_event(led_stop);
 179         return 0;
 180 }
 181
 182 static int leds_resume(struct sys_device *dev)
 183 {
 184         leds_event(led_start);
 185         return 0;
 186 }
 187
 188 static int leds_shutdown(struct sys_device *dev)
 189 {
 190         leds_event(led_halted);
 191         return 0;
 192 }
 193
 194 static struct sysdev_class leds_sysclass = {
 195         set_kset_name("leds"),
 196         .shutdown       = leds_shutdown,
 197         .suspend        = leds_suspend,
 198         .resume         = leds_resume,
 199 };
 200
 201 static struct sys_device leds_device = {
 202         .id             = 0,
 203         .cls            = &leds_sysclass,
 204 };
 205
 206 static int __init leds_init(void)
 207 {
 208         int ret;
 209         ret = sysdev_class_register(&leds_sysclass);
 210         if (ret == 0)
 211                 ret = sysdev_register(&leds_device);
 212         if (ret == 0)
 213                 ret = sysdev_create_file(&leds_device, &attr_event);
 214         return ret;
 215 }
 216
 217 device_initcall(leds_init);
 218
 219 EXPORT_SYMBOL(leds_event);
 220 #endif
 221
 222 #ifdef CONFIG_LEDS_TIMER
 223 static inline void do_leds(void)
 224 {
 225         static unsigned int count = HZ/2;
 226
 227         if (--count == 0) {
 228                 count = HZ/2;
 229                 leds_event(led_timer);
 230         }
 231 }
 232 #else
 233 #define do_leds()
 234 #endif
 235
 236 #ifndef CONFIG_GENERIC_TIME
 237 void do_gettimeofday(struct timeval *tv)
 238 {
 239         unsigned long flags;
 240         unsigned long seq;
 241         unsigned long usec, sec;
 242
 243         do {
 244                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 245                 usec = system_timer->offset();
 246                 sec = xtime.tv_sec;
 247                 usec += xtime.tv_nsec / 1000;
 248         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 249
 250         /* usec may have gone up a lot: be safe */
 251         while (usec >= 1000000) {
 252                 usec -= 1000000;
 253                 sec++;
 254         }
 255
 256         tv->tv_sec = sec;
 257         tv->tv_usec = usec;
 258 }
 259
 260 EXPORT_SYMBOL(do_gettimeofday);
 261
 262 int do_settimeofday(struct timespec *tv)
 263 {
 264         time_t wtm_sec, sec = tv->tv_sec;
 265         long wtm_nsec, nsec = tv->tv_nsec;
 266
 267         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 268                 return -EINVAL;
 269
 270         write_seqlock_irq(&xtime_lock);
 271         /*
 272          * This is revolting. We need to set "xtime" correctly. However, the
 273          * value in this location is the value at the most recent update of
 274          * wall time.  Discover what correction gettimeofday() would have
 275          * done, and then undo it!
 276          */
 277         nsec -= system_timer->offset() * NSEC_PER_USEC;
 278
 279         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 280         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 281
 282         set_normalized_timespec(&xtime, sec, nsec);
 283         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 284
 285         ntp_clear();
 286         write_sequnlock_irq(&xtime_lock);
 287         clock_was_set();
 288         return 0;
 289 }
 290
 291 EXPORT_SYMBOL(do_settimeofday);
 292 #endif /* !CONFIG_GENERIC_TIME */
 293
 294 /**
 295  * save_time_delta - Save the offset between system time and RTC time
 296  * @delta: pointer to timespec to store delta
 297  * @rtc: pointer to timespec for current RTC time
 298  *
 299  * Return a delta between the system time and the RTC time, such
 300  * that system time can be restored later with restore_time_delta()
 301  */
 302 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 303 {
 304         set_normalized_timespec(delta,
 305                                 xtime.tv_sec - rtc->tv_sec,
 306                                 xtime.tv_nsec - rtc->tv_nsec);
 307 }
 308 EXPORT_SYMBOL(save_time_delta);
 309
 310 /**
 311  * restore_time_delta - Restore the current system time
 312  * @delta: delta returned by save_time_delta()
 313  * @rtc: pointer to timespec for current RTC time
 314  */
 315 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 316 {
 317         struct timespec ts;
 318
 319         set_normalized_timespec(&ts,
 320                                 delta->tv_sec + rtc->tv_sec,
 321                                 delta->tv_nsec + rtc->tv_nsec);
 322
 323         do_settimeofday(&ts);
 324 }
 325 EXPORT_SYMBOL(restore_time_delta);
 326
 327 /*
 328  * Kernel system timer support.
 329  */
 330 void timer_tick(void)
 331 {
 332         profile_tick(CPU_PROFILING);
 333         do_leds();
 334         do_set_rtc();
 335         do_timer(1);
 336 #ifndef CONFIG_SMP
 337         update_process_times(user_mode(get_irq_regs()));
 338 #endif
 339 }
 340
 341 #ifdef CONFIG_PM
 342 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 343 {
 344         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 345
 346         if (timer->suspend != NULL)
 347                 timer->suspend();
 348
 349         return 0;
 350 }
 351
 352 static int timer_resume(struct sys_device *dev)
 353 {
 354         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 355
 356         if (timer->resume != NULL)
 357                 timer->resume();
 358
 359         return 0;
 360 }
 361 #else
 362 #define timer_suspend NULL
 363 #define timer_resume NULL
 364 #endif
 365
 366 static struct sysdev_class timer_sysclass = {
 367         set_kset_name("timer"),
 368         .suspend        = timer_suspend,
 369         .resume         = timer_resume,
 370 };
 371
 372 #ifdef CONFIG_NO_IDLE_HZ
 373 static int timer_dyn_tick_enable(void)
 374 {
 375         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 376         unsigned long flags;
 377         int ret = -ENODEV;
 378
 379         if (dyn_tick) {
 380                 spin_lock_irqsave(&dyn_tick->lock, flags);
 381                 ret = 0;
 382                 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
 383                         ret = dyn_tick->enable();
 384
 385                         if (ret == 0)
 386                                 dyn_tick->state |= DYN_TICK_ENABLED;
 387                 }
 388                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 389         }
 390
 391         return ret;
 392 }
 393
 394 static int timer_dyn_tick_disable(void)
 395 {
 396         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 397         unsigned long flags;
 398         int ret = -ENODEV;
 399
 400         if (dyn_tick) {
 401                 spin_lock_irqsave(&dyn_tick->lock, flags);
 402                 ret = 0;
 403                 if (dyn_tick->state & DYN_TICK_ENABLED) {
 404                         ret = dyn_tick->disable();
 405
 406                         if (ret == 0)
 407                                 dyn_tick->state &= ~DYN_TICK_ENABLED;
 408                 }
 409                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 410         }
 411
 412         return ret;
 413 }
 414
 415 /*
 416  * Reprogram the system timer for at least the calculated time interval.
 417  * This function should be called from the idle thread with IRQs disabled,
 418  * immediately before sleeping.
 419  */
 420 void timer_dyn_reprogram(void)
 421 {
 422         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 423         unsigned long next, seq, flags;
 424
 425         if (!dyn_tick)
 426                 return;
 427
 428         spin_lock_irqsave(&dyn_tick->lock, flags);
 429         if (dyn_tick->state & DYN_TICK_ENABLED) {
 430                 next = next_timer_interrupt();
 431                 do {
 432                         seq = read_seqbegin(&xtime_lock);
 433                         dyn_tick->reprogram(next - jiffies);
 434                 } while (read_seqretry(&xtime_lock, seq));
 435         }
 436         spin_unlock_irqrestore(&dyn_tick->lock, flags);
 437 }
 438
 439 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
 440 {
 441         return sprintf(buf, "%i\n",
 442                        (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
 443 }
 444
 445 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
 446                                   size_t count)
 447 {
 448         unsigned int enable = simple_strtoul(buf, NULL, 2);
 449
 450         if (enable)
 451                 timer_dyn_tick_enable();
 452         else
 453                 timer_dyn_tick_disable();
 454
 455         return count;
 456 }
 457 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
 458
 459 /*
 460  * dyntick=enable|disable
 461  */
 462 static char dyntick_str[4] __initdata = "";
 463
 464 static int __init dyntick_setup(char *str)
 465 {
 466         if (str)
 467                 strlcpy(dyntick_str, str, sizeof(dyntick_str));
 468         return 1;
 469 }
 470
 471 __setup("dyntick=", dyntick_setup);
 472 #endif
 473
 474 static int __init timer_init_sysfs(void)
 475 {
 476         int ret = sysdev_class_register(&timer_sysclass);
 477         if (ret == 0) {
 478                 system_timer->dev.cls = &timer_sysclass;
 479                 ret = sysdev_register(&system_timer->dev);
 480         }
 481
 482 #ifdef CONFIG_NO_IDLE_HZ
 483         if (ret == 0 && system_timer->dyn_tick) {
 484                 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
 485
 486                 /*
 487                  * Turn on dynamic tick after calibrate delay
 488                  * for correct bogomips
 489                  */
 490                 if (ret == 0 && dyntick_str[0] == 'e')
 491                         ret = timer_dyn_tick_enable();
 492         }
 493 #endif
 494
 495         return ret;
 496 }
 497
 498 device_initcall(timer_init_sysfs);
 499
 500 void __init time_init(void)
 501 {
 502 #ifndef CONFIG_GENERIC_TIME
 503         if (system_timer->offset == NULL)
 504                 system_timer->offset = dummy_gettimeoffset;
 505 #endif
 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