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 <asm/leds.h> 33 #include <asm/thread_info.h> 34 #include <asm/mach/time.h> 35 36 /* 37 * Our system timer. 38 */ 39 struct sys_timer *system_timer; 40 41 /* this needs a better home */ 42 DEFINE_SPINLOCK(rtc_lock); 43 44 #ifdef CONFIG_SA1100_RTC_MODULE 45 EXPORT_SYMBOL(rtc_lock); 46 #endif 47 48 /* change this if you have some constant time drift */ 49 #define USECS_PER_JIFFY (1000000/HZ) 50 51 #ifdef CONFIG_SMP 52 unsigned long profile_pc(struct pt_regs *regs) 53 { 54 unsigned long fp, pc = instruction_pointer(regs); 55 56 if (in_lock_functions(pc)) { 57 fp = regs->ARM_fp; 58 pc = pc_pointer(((unsigned long *)fp)[-1]); 59 } 60 61 return pc; 62 } 63 EXPORT_SYMBOL(profile_pc); 64 #endif 65 66 /* 67 * hook for setting the RTC's idea of the current time. 68 */ 69 int (*set_rtc)(void); 70 71 #ifndef CONFIG_GENERIC_TIME 72 static unsigned long dummy_gettimeoffset(void) 73 { 74 return 0; 75 } 76 #endif 77 78 /* 79 * Scheduler clock - returns current time in nanosec units. 80 * This is the default implementation. Sub-architecture 81 * implementations can override this. 82 */ 83 unsigned long long __attribute__((weak)) sched_clock(void) 84 { 85 return (unsigned long long)jiffies * (1000000000 / HZ); 86 } 87 88 static unsigned long next_rtc_update; 89 90 /* 91 * If we have an externally synchronized linux clock, then update 92 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be 93 * called as close as possible to 500 ms before the new second 94 * starts. 95 */ 96 static inline void do_set_rtc(void) 97 { 98 if (!ntp_synced() || set_rtc == NULL) 99 return; 100 101 if (next_rtc_update && 102 time_before((unsigned long)xtime.tv_sec, next_rtc_update)) 103 return; 104 105 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && 106 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) 107 return; 108 109 if (set_rtc()) 110 /* 111 * rtc update failed. Try again in 60s 112 */ 113 next_rtc_update = xtime.tv_sec + 60; 114 else 115 next_rtc_update = xtime.tv_sec + 660; 116 } 117 118 #ifdef CONFIG_LEDS 119 120 static void dummy_leds_event(led_event_t evt) 121 { 122 } 123 124 void (*leds_event)(led_event_t) = dummy_leds_event; 125 126 struct leds_evt_name { 127 const char name[8]; 128 int on; 129 int off; 130 }; 131 132 static const struct leds_evt_name evt_names[] = { 133 { "amber", led_amber_on, led_amber_off }, 134 { "blue", led_blue_on, led_blue_off }, 135 { "green", led_green_on, led_green_off }, 136 { "red", led_red_on, led_red_off }, 137 }; 138 139 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size) 140 { 141 int ret = -EINVAL, len = strcspn(buf, " "); 142 143 if (len > 0 && buf[len] == '\0') 144 len--; 145 146 if (strncmp(buf, "claim", len) == 0) { 147 leds_event(led_claim); 148 ret = size; 149 } else if (strncmp(buf, "release", len) == 0) { 150 leds_event(led_release); 151 ret = size; 152 } else { 153 int i; 154 155 for (i = 0; i < ARRAY_SIZE(evt_names); i++) { 156 if (strlen(evt_names[i].name) != len || 157 strncmp(buf, evt_names[i].name, len) != 0) 158 continue; 159 if (strncmp(buf+len, " on", 3) == 0) { 160 leds_event(evt_names[i].on); 161 ret = size; 162 } else if (strncmp(buf+len, " off", 4) == 0) { 163 leds_event(evt_names[i].off); 164 ret = size; 165 } 166 break; 167 } 168 } 169 return ret; 170 } 171 172 static SYSDEV_ATTR(event, 0200, NULL, leds_store); 173 174 static int leds_suspend(struct sys_device *dev, pm_message_t state) 175 { 176 leds_event(led_stop); 177 return 0; 178 } 179 180 static int leds_resume(struct sys_device *dev) 181 { 182 leds_event(led_start); 183 return 0; 184 } 185 186 static int leds_shutdown(struct sys_device *dev) 187 { 188 leds_event(led_halted); 189 return 0; 190 } 191 192 static struct sysdev_class leds_sysclass = { 193 set_kset_name("leds"), 194 .shutdown = leds_shutdown, 195 .suspend = leds_suspend, 196 .resume = leds_resume, 197 }; 198 199 static struct sys_device leds_device = { 200 .id = 0, 201 .cls = &leds_sysclass, 202 }; 203 204 static int __init leds_init(void) 205 { 206 int ret; 207 ret = sysdev_class_register(&leds_sysclass); 208 if (ret == 0) 209 ret = sysdev_register(&leds_device); 210 if (ret == 0) 211 ret = sysdev_create_file(&leds_device, &attr_event); 212 return ret; 213 } 214 215 device_initcall(leds_init); 216 217 EXPORT_SYMBOL(leds_event); 218 #endif 219 220 #ifdef CONFIG_LEDS_TIMER 221 static inline void do_leds(void) 222 { 223 static unsigned int count = HZ/2; 224 225 if (--count == 0) { 226 count = HZ/2; 227 leds_event(led_timer); 228 } 229 } 230 #else 231 #define do_leds() 232 #endif 233 234 #ifndef CONFIG_GENERIC_TIME 235 void do_gettimeofday(struct timeval *tv) 236 { 237 unsigned long flags; 238 unsigned long seq; 239 unsigned long usec, sec; 240 241 do { 242 seq = read_seqbegin_irqsave(&xtime_lock, flags); 243 usec = system_timer->offset(); 244 sec = xtime.tv_sec; 245 usec += xtime.tv_nsec / 1000; 246 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 247 248 /* usec may have gone up a lot: be safe */ 249 while (usec >= 1000000) { 250 usec -= 1000000; 251 sec++; 252 } 253 254 tv->tv_sec = sec; 255 tv->tv_usec = usec; 256 } 257 258 EXPORT_SYMBOL(do_gettimeofday); 259 260 int do_settimeofday(struct timespec *tv) 261 { 262 time_t wtm_sec, sec = tv->tv_sec; 263 long wtm_nsec, nsec = tv->tv_nsec; 264 265 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 266 return -EINVAL; 267 268 write_seqlock_irq(&xtime_lock); 269 /* 270 * This is revolting. We need to set "xtime" correctly. However, the 271 * value in this location is the value at the most recent update of 272 * wall time. Discover what correction gettimeofday() would have 273 * done, and then undo it! 274 */ 275 nsec -= system_timer->offset() * NSEC_PER_USEC; 276 277 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 278 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 279 280 set_normalized_timespec(&xtime, sec, nsec); 281 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 282 283 ntp_clear(); 284 write_sequnlock_irq(&xtime_lock); 285 clock_was_set(); 286 return 0; 287 } 288 289 EXPORT_SYMBOL(do_settimeofday); 290 #endif /* !CONFIG_GENERIC_TIME */ 291 292 /** 293 * save_time_delta - Save the offset between system time and RTC time 294 * @delta: pointer to timespec to store delta 295 * @rtc: pointer to timespec for current RTC time 296 * 297 * Return a delta between the system time and the RTC time, such 298 * that system time can be restored later with restore_time_delta() 299 */ 300 void save_time_delta(struct timespec *delta, struct timespec *rtc) 301 { 302 set_normalized_timespec(delta, 303 xtime.tv_sec - rtc->tv_sec, 304 xtime.tv_nsec - rtc->tv_nsec); 305 } 306 EXPORT_SYMBOL(save_time_delta); 307 308 /** 309 * restore_time_delta - Restore the current system time 310 * @delta: delta returned by save_time_delta() 311 * @rtc: pointer to timespec for current RTC time 312 */ 313 void restore_time_delta(struct timespec *delta, struct timespec *rtc) 314 { 315 struct timespec ts; 316 317 set_normalized_timespec(&ts, 318 delta->tv_sec + rtc->tv_sec, 319 delta->tv_nsec + rtc->tv_nsec); 320 321 do_settimeofday(&ts); 322 } 323 EXPORT_SYMBOL(restore_time_delta); 324 325 /* 326 * Kernel system timer support. 327 */ 328 void timer_tick(void) 329 { 330 profile_tick(CPU_PROFILING); 331 do_leds(); 332 do_set_rtc(); 333 do_timer(1); 334 #ifndef CONFIG_SMP 335 update_process_times(user_mode(get_irq_regs())); 336 #endif 337 } 338 339 #ifdef CONFIG_PM 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 set_kset_name("timer"), 366 .suspend = timer_suspend, 367 .resume = timer_resume, 368 }; 369 370 #ifdef CONFIG_NO_IDLE_HZ 371 static int timer_dyn_tick_enable(void) 372 { 373 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 374 unsigned long flags; 375 int ret = -ENODEV; 376 377 if (dyn_tick) { 378 spin_lock_irqsave(&dyn_tick->lock, flags); 379 ret = 0; 380 if (!(dyn_tick->state & DYN_TICK_ENABLED)) { 381 ret = dyn_tick->enable(); 382 383 if (ret == 0) 384 dyn_tick->state |= DYN_TICK_ENABLED; 385 } 386 spin_unlock_irqrestore(&dyn_tick->lock, flags); 387 } 388 389 return ret; 390 } 391 392 static int timer_dyn_tick_disable(void) 393 { 394 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 395 unsigned long flags; 396 int ret = -ENODEV; 397 398 if (dyn_tick) { 399 spin_lock_irqsave(&dyn_tick->lock, flags); 400 ret = 0; 401 if (dyn_tick->state & DYN_TICK_ENABLED) { 402 ret = dyn_tick->disable(); 403 404 if (ret == 0) 405 dyn_tick->state &= ~DYN_TICK_ENABLED; 406 } 407 spin_unlock_irqrestore(&dyn_tick->lock, flags); 408 } 409 410 return ret; 411 } 412 413 /* 414 * Reprogram the system timer for at least the calculated time interval. 415 * This function should be called from the idle thread with IRQs disabled, 416 * immediately before sleeping. 417 */ 418 void timer_dyn_reprogram(void) 419 { 420 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 421 unsigned long next, seq, flags; 422 423 if (!dyn_tick) 424 return; 425 426 spin_lock_irqsave(&dyn_tick->lock, flags); 427 if (dyn_tick->state & DYN_TICK_ENABLED) { 428 next = next_timer_interrupt(); 429 do { 430 seq = read_seqbegin(&xtime_lock); 431 dyn_tick->reprogram(next - jiffies); 432 } while (read_seqretry(&xtime_lock, seq)); 433 } 434 spin_unlock_irqrestore(&dyn_tick->lock, flags); 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 #ifndef CONFIG_GENERIC_TIME 501 if (system_timer->offset == NULL) 502 system_timer->offset = dummy_gettimeoffset; 503 #endif 504 system_timer->init(); 505 506 #ifdef CONFIG_NO_IDLE_HZ 507 if (system_timer->dyn_tick) 508 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED; 509 #endif 510 } 511 512