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 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
  44 /* this needs a better home */
  45 DEFINE_SPINLOCK(rtc_lock);
  46
  47 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
  48 EXPORT_SYMBOL(rtc_lock);
  49 #endif
  50 #endif  /* pc-style 'CMOS' RTC support */
  51
  52 /* change this if you have some constant time drift */
  53 #define USECS_PER_JIFFY (1000000/HZ)
  54
  55 #ifdef CONFIG_SMP
  56 unsigned long profile_pc(struct pt_regs *regs)
  57 {
  58         unsigned long fp, pc = instruction_pointer(regs);
  59
  60         if (in_lock_functions(pc)) {
  61                 fp = regs->ARM_fp;
  62                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  63         }
  64
  65         return pc;
  66 }
  67 EXPORT_SYMBOL(profile_pc);
  68 #endif
  69
  70 /*
  71  * hook for setting the RTC's idea of the current time.
  72  */
  73 int (*set_rtc)(void);
  74
  75 #ifndef CONFIG_GENERIC_TIME
  76 static unsigned long dummy_gettimeoffset(void)
  77 {
  78         return 0;
  79 }
  80 #endif
  81
  82 /*
  83  * An implementation of printk_clock() independent from
  84  * sched_clock().  This avoids non-bootable kernels when
  85  * printk_clock is enabled.
  86  */
  87 unsigned long long printk_clock(void)
  88 {
  89         return (unsigned long long)(jiffies - INITIAL_JIFFIES) *
  90                         (1000000000 / HZ);
  91 }
  92
  93 static unsigned long next_rtc_update;
  94
  95 /*
  96  * If we have an externally synchronized linux clock, then update
  97  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  98  * called as close as possible to 500 ms before the new second
  99  * starts.
 100  */
 101 static inline void do_set_rtc(void)
 102 {
 103         if (!ntp_synced() || set_rtc == NULL)
 104                 return;
 105
 106         if (next_rtc_update &&
 107             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 108                 return;
 109
 110         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 111             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 112                 return;
 113
 114         if (set_rtc())
 115                 /*
 116                  * rtc update failed.  Try again in 60s
 117                  */
 118                 next_rtc_update = xtime.tv_sec + 60;
 119         else
 120                 next_rtc_update = xtime.tv_sec + 660;
 121 }
 122
 123 #ifdef CONFIG_LEDS
 124
 125 static void dummy_leds_event(led_event_t evt)
 126 {
 127 }
 128
 129 void (*leds_event)(led_event_t) = dummy_leds_event;
 130
 131 struct leds_evt_name {
 132         const char      name[8];
 133         int             on;
 134         int             off;
 135 };
 136
 137 static const struct leds_evt_name evt_names[] = {
 138         { "amber", led_amber_on, led_amber_off },
 139         { "blue",  led_blue_on,  led_blue_off  },
 140         { "green", led_green_on, led_green_off },
 141         { "red",   led_red_on,   led_red_off   },
 142 };
 143
 144 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 145 {
 146         int ret = -EINVAL, len = strcspn(buf, " ");
 147
 148         if (len > 0 && buf[len] == '\0')
 149                 len--;
 150
 151         if (strncmp(buf, "claim", len) == 0) {
 152                 leds_event(led_claim);
 153                 ret = size;
 154         } else if (strncmp(buf, "release", len) == 0) {
 155                 leds_event(led_release);
 156                 ret = size;
 157         } else {
 158                 int i;
 159
 160                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 161                         if (strlen(evt_names[i].name) != len ||
 162                             strncmp(buf, evt_names[i].name, len) != 0)
 163                                 continue;
 164                         if (strncmp(buf+len, " on", 3) == 0) {
 165                                 leds_event(evt_names[i].on);
 166                                 ret = size;
 167                         } else if (strncmp(buf+len, " off", 4) == 0) {
 168                                 leds_event(evt_names[i].off);
 169                                 ret = size;
 170                         }
 171                         break;
 172                 }
 173         }
 174         return ret;
 175 }
 176
 177 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 178
 179 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 180 {
 181         leds_event(led_stop);
 182         return 0;
 183 }
 184
 185 static int leds_resume(struct sys_device *dev)
 186 {
 187         leds_event(led_start);
 188         return 0;
 189 }
 190
 191 static int leds_shutdown(struct sys_device *dev)
 192 {
 193         leds_event(led_halted);
 194         return 0;
 195 }
 196
 197 static struct sysdev_class leds_sysclass = {
 198         set_kset_name("leds"),
 199         .shutdown       = leds_shutdown,
 200         .suspend        = leds_suspend,
 201         .resume         = leds_resume,
 202 };
 203
 204 static struct sys_device leds_device = {
 205         .id             = 0,
 206         .cls            = &leds_sysclass,
 207 };
 208
 209 static int __init leds_init(void)
 210 {
 211         int ret;
 212         ret = sysdev_class_register(&leds_sysclass);
 213         if (ret == 0)
 214                 ret = sysdev_register(&leds_device);
 215         if (ret == 0)
 216                 ret = sysdev_create_file(&leds_device, &attr_event);
 217         return ret;
 218 }
 219
 220 device_initcall(leds_init);
 221
 222 EXPORT_SYMBOL(leds_event);
 223 #endif
 224
 225 #ifdef CONFIG_LEDS_TIMER
 226 static inline void do_leds(void)
 227 {
 228         static unsigned int count = HZ/2;
 229
 230         if (--count == 0) {
 231                 count = HZ/2;
 232                 leds_event(led_timer);
 233         }
 234 }
 235 #else
 236 #define do_leds()
 237 #endif
 238
 239 #ifndef CONFIG_GENERIC_TIME
 240 void do_gettimeofday(struct timeval *tv)
 241 {
 242         unsigned long flags;
 243         unsigned long seq;
 244         unsigned long usec, sec;
 245
 246         do {
 247                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 248                 usec = system_timer->offset();
 249                 sec = xtime.tv_sec;
 250                 usec += xtime.tv_nsec / 1000;
 251         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 252
 253         /* usec may have gone up a lot: be safe */
 254         while (usec >= 1000000) {
 255                 usec -= 1000000;
 256                 sec++;
 257         }
 258
 259         tv->tv_sec = sec;
 260         tv->tv_usec = usec;
 261 }
 262
 263 EXPORT_SYMBOL(do_gettimeofday);
 264
 265 int do_settimeofday(struct timespec *tv)
 266 {
 267         time_t wtm_sec, sec = tv->tv_sec;
 268         long wtm_nsec, nsec = tv->tv_nsec;
 269
 270         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 271                 return -EINVAL;
 272
 273         write_seqlock_irq(&xtime_lock);
 274         /*
 275          * This is revolting. We need to set "xtime" correctly. However, the
 276          * value in this location is the value at the most recent update of
 277          * wall time.  Discover what correction gettimeofday() would have
 278          * done, and then undo it!
 279          */
 280         nsec -= system_timer->offset() * NSEC_PER_USEC;
 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 #endif /* !CONFIG_GENERIC_TIME */
 296
 297 /**
 298  * save_time_delta - Save the offset between system time and RTC time
 299  * @delta: pointer to timespec to store delta
 300  * @rtc: pointer to timespec for current RTC time
 301  *
 302  * Return a delta between the system time and the RTC time, such
 303  * that system time can be restored later with restore_time_delta()
 304  */
 305 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 306 {
 307         set_normalized_timespec(delta,
 308                                 xtime.tv_sec - rtc->tv_sec,
 309                                 xtime.tv_nsec - rtc->tv_nsec);
 310 }
 311 EXPORT_SYMBOL(save_time_delta);
 312
 313 /**
 314  * restore_time_delta - Restore the current system time
 315  * @delta: delta returned by save_time_delta()
 316  * @rtc: pointer to timespec for current RTC time
 317  */
 318 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 319 {
 320         struct timespec ts;
 321
 322         set_normalized_timespec(&ts,
 323                                 delta->tv_sec + rtc->tv_sec,
 324                                 delta->tv_nsec + rtc->tv_nsec);
 325
 326         do_settimeofday(&ts);
 327 }
 328 EXPORT_SYMBOL(restore_time_delta);
 329
 330 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 331 /*
 332  * Kernel system timer support.
 333  */
 334 void timer_tick(void)
 335 {
 336         profile_tick(CPU_PROFILING);
 337         do_leds();
 338         do_set_rtc();
 339         do_timer(1);
 340 #ifndef CONFIG_SMP
 341         update_process_times(user_mode(get_irq_regs()));
 342 #endif
 343 }
 344 #endif
 345
 346 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
 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                 spin_lock_init(&system_timer->dyn_tick->lock);
 516 #endif
 517 }
 518