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/hardware.h>
  33 #include <asm/io.h>
  34 #include <asm/irq.h>
  35 #include <asm/leds.h>
  36 #include <asm/thread_info.h>
  37 #include <asm/mach/time.h>
  38
  39 /*
  40  * Our system timer.
  41  */
  42 struct sys_timer *system_timer;
  43
  44 extern unsigned long wall_jiffies;
  45
  46 /* this needs a better home */
  47 DEFINE_SPINLOCK(rtc_lock);
  48
  49 #ifdef CONFIG_SA1100_RTC_MODULE
  50 EXPORT_SYMBOL(rtc_lock);
  51 #endif
  52
  53 /* change this if you have some constant time drift */
  54 #define USECS_PER_JIFFY (1000000/HZ)
  55
  56 #ifdef CONFIG_SMP
  57 unsigned long profile_pc(struct pt_regs *regs)
  58 {
  59         unsigned long fp, pc = instruction_pointer(regs);
  60
  61         if (in_lock_functions(pc)) {
  62                 fp = regs->ARM_fp;
  63                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  64         }
  65
  66         return pc;
  67 }
  68 EXPORT_SYMBOL(profile_pc);
  69 #endif
  70
  71 /*
  72  * hook for setting the RTC's idea of the current time.
  73  */
  74 int (*set_rtc)(void);
  75
  76 static unsigned long dummy_gettimeoffset(void)
  77 {
  78         return 0;
  79 }
  80
  81 /*
  82  * Scheduler clock - returns current time in nanosec units.
  83  * This is the default implementation.  Sub-architecture
  84  * implementations can override this.
  85  */
  86 unsigned long long __attribute__((weak)) sched_clock(void)
  87 {
  88         return (unsigned long long)jiffies * (1000000000 / HZ);
  89 }
  90
  91 static unsigned long next_rtc_update;
  92
  93 /*
  94  * If we have an externally synchronized linux clock, then update
  95  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  96  * called as close as possible to 500 ms before the new second
  97  * starts.
  98  */
  99 static inline void do_set_rtc(void)
 100 {
 101         if (!ntp_synced() || set_rtc == NULL)
 102                 return;
 103
 104         if (next_rtc_update &&
 105             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 106                 return;
 107
 108         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 109             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 110                 return;
 111
 112         if (set_rtc())
 113                 /*
 114                  * rtc update failed.  Try again in 60s
 115                  */
 116                 next_rtc_update = xtime.tv_sec + 60;
 117         else
 118                 next_rtc_update = xtime.tv_sec + 660;
 119 }
 120
 121 #ifdef CONFIG_LEDS
 122
 123 static void dummy_leds_event(led_event_t evt)
 124 {
 125 }
 126
 127 void (*leds_event)(led_event_t) = dummy_leds_event;
 128
 129 struct leds_evt_name {
 130         const char      name[8];
 131         int             on;
 132         int             off;
 133 };
 134
 135 static const struct leds_evt_name evt_names[] = {
 136         { "amber", led_amber_on, led_amber_off },
 137         { "blue",  led_blue_on,  led_blue_off  },
 138         { "green", led_green_on, led_green_off },
 139         { "red",   led_red_on,   led_red_off   },
 140 };
 141
 142 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 143 {
 144         int ret = -EINVAL, len = strcspn(buf, " ");
 145
 146         if (len > 0 && buf[len] == '\0')
 147                 len--;
 148
 149         if (strncmp(buf, "claim", len) == 0) {
 150                 leds_event(led_claim);
 151                 ret = size;
 152         } else if (strncmp(buf, "release", len) == 0) {
 153                 leds_event(led_release);
 154                 ret = size;
 155         } else {
 156                 int i;
 157
 158                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 159                         if (strlen(evt_names[i].name) != len ||
 160                             strncmp(buf, evt_names[i].name, len) != 0)
 161                                 continue;
 162                         if (strncmp(buf+len, " on", 3) == 0) {
 163                                 leds_event(evt_names[i].on);
 164                                 ret = size;
 165                         } else if (strncmp(buf+len, " off", 4) == 0) {
 166                                 leds_event(evt_names[i].off);
 167                                 ret = size;
 168                         }
 169                         break;
 170                 }
 171         }
 172         return ret;
 173 }
 174
 175 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 176
 177 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 178 {
 179         leds_event(led_stop);
 180         return 0;
 181 }
 182
 183 static int leds_resume(struct sys_device *dev)
 184 {
 185         leds_event(led_start);
 186         return 0;
 187 }
 188
 189 static int leds_shutdown(struct sys_device *dev)
 190 {
 191         leds_event(led_halted);
 192         return 0;
 193 }
 194
 195 static struct sysdev_class leds_sysclass = {
 196         set_kset_name("leds"),
 197         .shutdown       = leds_shutdown,
 198         .suspend        = leds_suspend,
 199         .resume         = leds_resume,
 200 };
 201
 202 static struct sys_device leds_device = {
 203         .id             = 0,
 204         .cls            = &leds_sysclass,
 205 };
 206
 207 static int __init leds_init(void)
 208 {
 209         int ret;
 210         ret = sysdev_class_register(&leds_sysclass);
 211         if (ret == 0)
 212                 ret = sysdev_register(&leds_device);
 213         if (ret == 0)
 214                 ret = sysdev_create_file(&leds_device, &attr_event);
 215         return ret;
 216 }
 217
 218 device_initcall(leds_init);
 219
 220 EXPORT_SYMBOL(leds_event);
 221 #endif
 222
 223 #ifdef CONFIG_LEDS_TIMER
 224 static inline void do_leds(void)
 225 {
 226         static unsigned int count = 50;
 227
 228         if (--count == 0) {
 229                 count = 50;
 230                 leds_event(led_timer);
 231         }
 232 }
 233 #else
 234 #define do_leds()
 235 #endif
 236
 237 void do_gettimeofday(struct timeval *tv)
 238 {
 239         unsigned long flags;
 240         unsigned long seq;
 241         unsigned long usec, sec, lost;
 242
 243         do {
 244                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 245                 usec = system_timer->offset();
 246
 247                 lost = jiffies - wall_jiffies;
 248                 if (lost)
 249                         usec += lost * USECS_PER_JIFFY;
 250
 251                 sec = xtime.tv_sec;
 252                 usec += xtime.tv_nsec / 1000;
 253         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 254
 255         /* usec may have gone up a lot: be safe */
 256         while (usec >= 1000000) {
 257                 usec -= 1000000;
 258                 sec++;
 259         }
 260
 261         tv->tv_sec = sec;
 262         tv->tv_usec = usec;
 263 }
 264
 265 EXPORT_SYMBOL(do_gettimeofday);
 266
 267 int do_settimeofday(struct timespec *tv)
 268 {
 269         time_t wtm_sec, sec = tv->tv_sec;
 270         long wtm_nsec, nsec = tv->tv_nsec;
 271
 272         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 273                 return -EINVAL;
 274
 275         write_seqlock_irq(&xtime_lock);
 276         /*
 277          * This is revolting. We need to set "xtime" correctly. However, the
 278          * value in this location is the value at the most recent update of
 279          * wall time.  Discover what correction gettimeofday() would have
 280          * done, and then undo it!
 281          */
 282         nsec -= system_timer->offset() * NSEC_PER_USEC;
 283         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 284
 285         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 286         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 287
 288         set_normalized_timespec(&xtime, sec, nsec);
 289         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 290
 291         ntp_clear();
 292         write_sequnlock_irq(&xtime_lock);
 293         clock_was_set();
 294         return 0;
 295 }
 296
 297 EXPORT_SYMBOL(do_settimeofday);
 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                 write_seqlock_irqsave(&xtime_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                 write_sequnlock_irqrestore(&xtime_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                 write_seqlock_irqsave(&xtime_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                 write_sequnlock_irqrestore(&xtime_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
 429         if (dyn_tick) {
 430                 write_seqlock(&xtime_lock);
 431                 if (dyn_tick->state & DYN_TICK_ENABLED)
 432                         dyn_tick->reprogram(next_timer_interrupt() - jiffies);
 433                 write_sequnlock(&xtime_lock);
 434         }
 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         if (system_timer->offset == NULL)
 501                 system_timer->offset = dummy_gettimeoffset;
 502         system_timer->init();
 503 }
 504