kernel/2.6.29.6-aldebaran-rt/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 = ((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 static unsigned long next_rtc_update;
  83
  84 /*
  85  * If we have an externally synchronized linux clock, then update
  86  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  87  * called as close as possible to 500 ms before the new second
  88  * starts.
  89  */
  90 static inline void do_set_rtc(void)
  91 {
  92         if (!ntp_synced() || set_rtc == NULL)
  93                 return;
  94
  95         if (next_rtc_update &&
  96             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
  97                 return;
  98
  99         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 100             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 101                 return;
 102
 103         if (set_rtc())
 104                 /*
 105                  * rtc update failed.  Try again in 60s
 106                  */
 107                 next_rtc_update = xtime.tv_sec + 60;
 108         else
 109                 next_rtc_update = xtime.tv_sec + 660;
 110 }
 111
 112 #ifdef CONFIG_LEDS
 113
 114 static void dummy_leds_event(led_event_t evt)
 115 {
 116 }
 117
 118 void (*leds_event)(led_event_t) = dummy_leds_event;
 119
 120 struct leds_evt_name {
 121         const char      name[8];
 122         int             on;
 123         int             off;
 124 };
 125
 126 static const struct leds_evt_name evt_names[] = {
 127         { "amber", led_amber_on, led_amber_off },
 128         { "blue",  led_blue_on,  led_blue_off  },
 129         { "green", led_green_on, led_green_off },
 130         { "red",   led_red_on,   led_red_off   },
 131 };
 132
 133 static ssize_t leds_store(struct sys_device *dev,
 134                         struct sysdev_attribute *attr,
 135                         const char *buf, size_t size)
 136 {
 137         int ret = -EINVAL, len = strcspn(buf, " ");
 138
 139         if (len > 0 && buf[len] == '\0')
 140                 len--;
 141
 142         if (strncmp(buf, "claim", len) == 0) {
 143                 leds_event(led_claim);
 144                 ret = size;
 145         } else if (strncmp(buf, "release", len) == 0) {
 146                 leds_event(led_release);
 147                 ret = size;
 148         } else {
 149                 int i;
 150
 151                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 152                         if (strlen(evt_names[i].name) != len ||
 153                             strncmp(buf, evt_names[i].name, len) != 0)
 154                                 continue;
 155                         if (strncmp(buf+len, " on", 3) == 0) {
 156                                 leds_event(evt_names[i].on);
 157                                 ret = size;
 158                         } else if (strncmp(buf+len, " off", 4) == 0) {
 159                                 leds_event(evt_names[i].off);
 160                                 ret = size;
 161                         }
 162                         break;
 163                 }
 164         }
 165         return ret;
 166 }
 167
 168 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 169
 170 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 171 {
 172         leds_event(led_stop);
 173         return 0;
 174 }
 175
 176 static int leds_resume(struct sys_device *dev)
 177 {
 178         leds_event(led_start);
 179         return 0;
 180 }
 181
 182 static int leds_shutdown(struct sys_device *dev)
 183 {
 184         leds_event(led_halted);
 185         return 0;
 186 }
 187
 188 static struct sysdev_class leds_sysclass = {
 189         .name           = "leds",
 190         .shutdown       = leds_shutdown,
 191         .suspend        = leds_suspend,
 192         .resume         = leds_resume,
 193 };
 194
 195 static struct sys_device leds_device = {
 196         .id             = 0,
 197         .cls            = &leds_sysclass,
 198 };
 199
 200 static int __init leds_init(void)
 201 {
 202         int ret;
 203         ret = sysdev_class_register(&leds_sysclass);
 204         if (ret == 0)
 205                 ret = sysdev_register(&leds_device);
 206         if (ret == 0)
 207                 ret = sysdev_create_file(&leds_device, &attr_event);
 208         return ret;
 209 }
 210
 211 device_initcall(leds_init);
 212
 213 EXPORT_SYMBOL(leds_event);
 214 #endif
 215
 216 #ifdef CONFIG_LEDS_TIMER
 217 static inline void do_leds(void)
 218 {
 219         static unsigned int count = HZ/2;
 220
 221         if (--count == 0) {
 222                 count = HZ/2;
 223                 leds_event(led_timer);
 224         }
 225 }
 226 #else
 227 #define do_leds()
 228 #endif
 229
 230 #ifndef CONFIG_GENERIC_TIME
 231 void do_gettimeofday(struct timeval *tv)
 232 {
 233         unsigned long flags;
 234         unsigned long seq;
 235         unsigned long usec, sec;
 236
 237         do {
 238                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 239                 usec = system_timer->offset();
 240                 sec = xtime.tv_sec;
 241                 usec += xtime.tv_nsec / 1000;
 242         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 243
 244         /* usec may have gone up a lot: be safe */
 245         while (usec >= 1000000) {
 246                 usec -= 1000000;
 247                 sec++;
 248         }
 249
 250         tv->tv_sec = sec;
 251         tv->tv_usec = usec;
 252 }
 253
 254 EXPORT_SYMBOL(do_gettimeofday);
 255
 256 int do_settimeofday(struct timespec *tv)
 257 {
 258         time_t wtm_sec, sec = tv->tv_sec;
 259         long wtm_nsec, nsec = tv->tv_nsec;
 260
 261         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 262                 return -EINVAL;
 263
 264         write_seqlock_irq(&xtime_lock);
 265         /*
 266          * This is revolting. We need to set "xtime" correctly. However, the
 267          * value in this location is the value at the most recent update of
 268          * wall time.  Discover what correction gettimeofday() would have
 269          * done, and then undo it!
 270          */
 271         nsec -= system_timer->offset() * NSEC_PER_USEC;
 272
 273         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 274         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 275
 276         set_normalized_timespec(&xtime, sec, nsec);
 277         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 278
 279         ntp_clear();
 280         write_sequnlock_irq(&xtime_lock);
 281         clock_was_set();
 282         return 0;
 283 }
 284
 285 EXPORT_SYMBOL(do_settimeofday);
 286 #endif /* !CONFIG_GENERIC_TIME */
 287
 288 /**
 289  * save_time_delta - Save the offset between system time and RTC time
 290  * @delta: pointer to timespec to store delta
 291  * @rtc: pointer to timespec for current RTC time
 292  *
 293  * Return a delta between the system time and the RTC time, such
 294  * that system time can be restored later with restore_time_delta()
 295  */
 296 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 297 {
 298         set_normalized_timespec(delta,
 299                                 xtime.tv_sec - rtc->tv_sec,
 300                                 xtime.tv_nsec - rtc->tv_nsec);
 301 }
 302 EXPORT_SYMBOL(save_time_delta);
 303
 304 /**
 305  * restore_time_delta - Restore the current system time
 306  * @delta: delta returned by save_time_delta()
 307  * @rtc: pointer to timespec for current RTC time
 308  */
 309 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 310 {
 311         struct timespec ts;
 312
 313         set_normalized_timespec(&ts,
 314                                 delta->tv_sec + rtc->tv_sec,
 315                                 delta->tv_nsec + rtc->tv_nsec);
 316
 317         do_settimeofday(&ts);
 318 }
 319 EXPORT_SYMBOL(restore_time_delta);
 320
 321 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 322 /*
 323  * Kernel system timer support.
 324  */
 325 void timer_tick(void)
 326 {
 327         profile_tick(CPU_PROFILING);
 328         do_leds();
 329         do_set_rtc();
 330         write_seqlock(&xtime_lock);
 331         do_timer(1);
 332         write_sequnlock(&xtime_lock);
 333 #ifndef CONFIG_SMP
 334         update_process_times(user_mode(get_irq_regs()));
 335 #endif
 336 }
 337 #endif
 338
 339 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
 340 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 341 {
 342         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 343
 344         if (timer->suspend != NULL)
 345                 timer->suspend();
 346
 347         return 0;
 348 }
 349
 350 static int timer_resume(struct sys_device *dev)
 351 {
 352         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 353
 354         if (timer->resume != NULL)
 355                 timer->resume();
 356
 357         return 0;
 358 }
 359 #else
 360 #define timer_suspend NULL
 361 #define timer_resume NULL
 362 #endif
 363
 364 static struct sysdev_class timer_sysclass = {
 365         .name           = "timer",
 366         .suspend        = timer_suspend,
 367         .resume         = timer_resume,
 368 };
 369
 370 static int __init timer_init_sysfs(void)
 371 {
 372         int ret = sysdev_class_register(&timer_sysclass);
 373         if (ret == 0) {
 374                 system_timer->dev.cls = &timer_sysclass;
 375                 ret = sysdev_register(&system_timer->dev);
 376         }
 377
 378         return ret;
 379 }
 380
 381 device_initcall(timer_init_sysfs);
 382
 383 void __init time_init(void)
 384 {
 385 #ifndef CONFIG_GENERIC_TIME
 386         if (system_timer->offset == NULL)
 387                 system_timer->offset = dummy_gettimeoffset;
 388 #endif
 389         system_timer->init();
 390 }
 391