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 /*
  91  * An implementation of printk_clock() independent from
  92  * sched_clock().  This avoids non-bootable kernels when
  93  * printk_clock is enabled.
  94  */
  95 unsigned long long printk_clock(void)
  96 {
  97         return (unsigned long long)(jiffies - INITIAL_JIFFIES) *
  98                         (1000000000 / HZ);
  99 }
 100
 101 static unsigned long next_rtc_update;
 102
 103 /*
 104  * If we have an externally synchronized linux clock, then update
 105  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
 106  * called as close as possible to 500 ms before the new second
 107  * starts.
 108  */
 109 static inline void do_set_rtc(void)
 110 {
 111         if (!ntp_synced() || set_rtc == NULL)
 112                 return;
 113
 114         if (next_rtc_update &&
 115             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 116                 return;
 117
 118         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 119             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 120                 return;
 121
 122         if (set_rtc())
 123                 /*
 124                  * rtc update failed.  Try again in 60s
 125                  */
 126                 next_rtc_update = xtime.tv_sec + 60;
 127         else
 128                 next_rtc_update = xtime.tv_sec + 660;
 129 }
 130
 131 #ifdef CONFIG_LEDS
 132
 133 static void dummy_leds_event(led_event_t evt)
 134 {
 135 }
 136
 137 void (*leds_event)(led_event_t) = dummy_leds_event;
 138
 139 struct leds_evt_name {
 140         const char      name[8];
 141         int             on;
 142         int             off;
 143 };
 144
 145 static const struct leds_evt_name evt_names[] = {
 146         { "amber", led_amber_on, led_amber_off },
 147         { "blue",  led_blue_on,  led_blue_off  },
 148         { "green", led_green_on, led_green_off },
 149         { "red",   led_red_on,   led_red_off   },
 150 };
 151
 152 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 153 {
 154         int ret = -EINVAL, len = strcspn(buf, " ");
 155
 156         if (len > 0 && buf[len] == '\0')
 157                 len--;
 158
 159         if (strncmp(buf, "claim", len) == 0) {
 160                 leds_event(led_claim);
 161                 ret = size;
 162         } else if (strncmp(buf, "release", len) == 0) {
 163                 leds_event(led_release);
 164                 ret = size;
 165         } else {
 166                 int i;
 167
 168                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 169                         if (strlen(evt_names[i].name) != len ||
 170                             strncmp(buf, evt_names[i].name, len) != 0)
 171                                 continue;
 172                         if (strncmp(buf+len, " on", 3) == 0) {
 173                                 leds_event(evt_names[i].on);
 174                                 ret = size;
 175                         } else if (strncmp(buf+len, " off", 4) == 0) {
 176                                 leds_event(evt_names[i].off);
 177                                 ret = size;
 178                         }
 179                         break;
 180                 }
 181         }
 182         return ret;
 183 }
 184
 185 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 186
 187 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 188 {
 189         leds_event(led_stop);
 190         return 0;
 191 }
 192
 193 static int leds_resume(struct sys_device *dev)
 194 {
 195         leds_event(led_start);
 196         return 0;
 197 }
 198
 199 static int leds_shutdown(struct sys_device *dev)
 200 {
 201         leds_event(led_halted);
 202         return 0;
 203 }
 204
 205 static struct sysdev_class leds_sysclass = {
 206         set_kset_name("leds"),
 207         .shutdown       = leds_shutdown,
 208         .suspend        = leds_suspend,
 209         .resume         = leds_resume,
 210 };
 211
 212 static struct sys_device leds_device = {
 213         .id             = 0,
 214         .cls            = &leds_sysclass,
 215 };
 216
 217 static int __init leds_init(void)
 218 {
 219         int ret;
 220         ret = sysdev_class_register(&leds_sysclass);
 221         if (ret == 0)
 222                 ret = sysdev_register(&leds_device);
 223         if (ret == 0)
 224                 ret = sysdev_create_file(&leds_device, &attr_event);
 225         return ret;
 226 }
 227
 228 device_initcall(leds_init);
 229
 230 EXPORT_SYMBOL(leds_event);
 231 #endif
 232
 233 #ifdef CONFIG_LEDS_TIMER
 234 static inline void do_leds(void)
 235 {
 236         static unsigned int count = HZ/2;
 237
 238         if (--count == 0) {
 239                 count = HZ/2;
 240                 leds_event(led_timer);
 241         }
 242 }
 243 #else
 244 #define do_leds()
 245 #endif
 246
 247 #ifndef CONFIG_GENERIC_TIME
 248 void do_gettimeofday(struct timeval *tv)
 249 {
 250         unsigned long flags;
 251         unsigned long seq;
 252         unsigned long usec, sec;
 253
 254         do {
 255                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 256                 usec = system_timer->offset();
 257                 sec = xtime.tv_sec;
 258                 usec += xtime.tv_nsec / 1000;
 259         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 260
 261         /* usec may have gone up a lot: be safe */
 262         while (usec >= 1000000) {
 263                 usec -= 1000000;
 264                 sec++;
 265         }
 266
 267         tv->tv_sec = sec;
 268         tv->tv_usec = usec;
 269 }
 270
 271 EXPORT_SYMBOL(do_gettimeofday);
 272
 273 int do_settimeofday(struct timespec *tv)
 274 {
 275         time_t wtm_sec, sec = tv->tv_sec;
 276         long wtm_nsec, nsec = tv->tv_nsec;
 277
 278         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 279                 return -EINVAL;
 280
 281         write_seqlock_irq(&xtime_lock);
 282         /*
 283          * This is revolting. We need to set "xtime" correctly. However, the
 284          * value in this location is the value at the most recent update of
 285          * wall time.  Discover what correction gettimeofday() would have
 286          * done, and then undo it!
 287          */
 288         nsec -= system_timer->offset() * NSEC_PER_USEC;
 289
 290         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 291         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 292
 293         set_normalized_timespec(&xtime, sec, nsec);
 294         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 295
 296         ntp_clear();
 297         write_sequnlock_irq(&xtime_lock);
 298         clock_was_set();
 299         return 0;
 300 }
 301
 302 EXPORT_SYMBOL(do_settimeofday);
 303 #endif /* !CONFIG_GENERIC_TIME */
 304
 305 /**
 306  * save_time_delta - Save the offset between system time and RTC time
 307  * @delta: pointer to timespec to store delta
 308  * @rtc: pointer to timespec for current RTC time
 309  *
 310  * Return a delta between the system time and the RTC time, such
 311  * that system time can be restored later with restore_time_delta()
 312  */
 313 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 314 {
 315         set_normalized_timespec(delta,
 316                                 xtime.tv_sec - rtc->tv_sec,
 317                                 xtime.tv_nsec - rtc->tv_nsec);
 318 }
 319 EXPORT_SYMBOL(save_time_delta);
 320
 321 /**
 322  * restore_time_delta - Restore the current system time
 323  * @delta: delta returned by save_time_delta()
 324  * @rtc: pointer to timespec for current RTC time
 325  */
 326 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 327 {
 328         struct timespec ts;
 329
 330         set_normalized_timespec(&ts,
 331                                 delta->tv_sec + rtc->tv_sec,
 332                                 delta->tv_nsec + rtc->tv_nsec);
 333
 334         do_settimeofday(&ts);
 335 }
 336 EXPORT_SYMBOL(restore_time_delta);
 337
 338 /*
 339  * Kernel system timer support.
 340  */
 341 void timer_tick(void)
 342 {
 343         profile_tick(CPU_PROFILING);
 344         do_leds();
 345         do_set_rtc();
 346         do_timer(1);
 347 #ifndef CONFIG_SMP
 348         update_process_times(user_mode(get_irq_regs()));
 349 #endif
 350 }
 351
 352 #ifdef CONFIG_PM
 353 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 354 {
 355         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 356
 357         if (timer->suspend != NULL)
 358                 timer->suspend();
 359
 360         return 0;
 361 }
 362
 363 static int timer_resume(struct sys_device *dev)
 364 {
 365         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 366
 367         if (timer->resume != NULL)
 368                 timer->resume();
 369
 370         return 0;
 371 }
 372 #else
 373 #define timer_suspend NULL
 374 #define timer_resume NULL
 375 #endif
 376
 377 static struct sysdev_class timer_sysclass = {
 378         set_kset_name("timer"),
 379         .suspend        = timer_suspend,
 380         .resume         = timer_resume,
 381 };
 382
 383 #ifdef CONFIG_NO_IDLE_HZ
 384 static int timer_dyn_tick_enable(void)
 385 {
 386         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 387         unsigned long flags;
 388         int ret = -ENODEV;
 389
 390         if (dyn_tick) {
 391                 spin_lock_irqsave(&dyn_tick->lock, flags);
 392                 ret = 0;
 393                 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
 394                         ret = dyn_tick->enable();
 395
 396                         if (ret == 0)
 397                                 dyn_tick->state |= DYN_TICK_ENABLED;
 398                 }
 399                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 400         }
 401
 402         return ret;
 403 }
 404
 405 static int timer_dyn_tick_disable(void)
 406 {
 407         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 408         unsigned long flags;
 409         int ret = -ENODEV;
 410
 411         if (dyn_tick) {
 412                 spin_lock_irqsave(&dyn_tick->lock, flags);
 413                 ret = 0;
 414                 if (dyn_tick->state & DYN_TICK_ENABLED) {
 415                         ret = dyn_tick->disable();
 416
 417                         if (ret == 0)
 418                                 dyn_tick->state &= ~DYN_TICK_ENABLED;
 419                 }
 420                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 421         }
 422
 423         return ret;
 424 }
 425
 426 /*
 427  * Reprogram the system timer for at least the calculated time interval.
 428  * This function should be called from the idle thread with IRQs disabled,
 429  * immediately before sleeping.
 430  */
 431 void timer_dyn_reprogram(void)
 432 {
 433         struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
 434         unsigned long next, seq, flags;
 435
 436         if (!dyn_tick)
 437                 return;
 438
 439         spin_lock_irqsave(&dyn_tick->lock, flags);
 440         if (dyn_tick->state & DYN_TICK_ENABLED) {
 441                 next = next_timer_interrupt();
 442                 do {
 443                         seq = read_seqbegin(&xtime_lock);
 444                         dyn_tick->reprogram(next - jiffies);
 445                 } while (read_seqretry(&xtime_lock, seq));
 446         }
 447         spin_unlock_irqrestore(&dyn_tick->lock, flags);
 448 }
 449
 450 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
 451 {
 452         return sprintf(buf, "%i\n",
 453                        (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
 454 }
 455
 456 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
 457                                   size_t count)
 458 {
 459         unsigned int enable = simple_strtoul(buf, NULL, 2);
 460
 461         if (enable)
 462                 timer_dyn_tick_enable();
 463         else
 464                 timer_dyn_tick_disable();
 465
 466         return count;
 467 }
 468 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
 469
 470 /*
 471  * dyntick=enable|disable
 472  */
 473 static char dyntick_str[4] __initdata = "";
 474
 475 static int __init dyntick_setup(char *str)
 476 {
 477         if (str)
 478                 strlcpy(dyntick_str, str, sizeof(dyntick_str));
 479         return 1;
 480 }
 481
 482 __setup("dyntick=", dyntick_setup);
 483 #endif
 484
 485 static int __init timer_init_sysfs(void)
 486 {
 487         int ret = sysdev_class_register(&timer_sysclass);
 488         if (ret == 0) {
 489                 system_timer->dev.cls = &timer_sysclass;
 490                 ret = sysdev_register(&system_timer->dev);
 491         }
 492
 493 #ifdef CONFIG_NO_IDLE_HZ
 494         if (ret == 0 && system_timer->dyn_tick) {
 495                 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
 496
 497                 /*
 498                  * Turn on dynamic tick after calibrate delay
 499                  * for correct bogomips
 500                  */
 501                 if (ret == 0 && dyntick_str[0] == 'e')
 502                         ret = timer_dyn_tick_enable();
 503         }
 504 #endif
 505
 506         return ret;
 507 }
 508
 509 device_initcall(timer_init_sysfs);
 510
 511 void __init time_init(void)
 512 {
 513 #ifndef CONFIG_GENERIC_TIME
 514         if (system_timer->offset == NULL)
 515                 system_timer->offset = dummy_gettimeoffset;
 516 #endif
 517         system_timer->init();
 518
 519 #ifdef CONFIG_NO_IDLE_HZ
 520         if (system_timer->dyn_tick)
 521                 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
 522 #endif
 523 }
 524