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 /* 331 * Kernel system timer support. 332 */ 333 void timer_tick(void) 334 { 335 profile_tick(CPU_PROFILING); 336 do_leds(); 337 do_set_rtc(); 338 do_timer(1); 339 #ifndef CONFIG_SMP 340 update_process_times(user_mode(get_irq_regs())); 341 #endif 342 } 343 344 #ifdef CONFIG_PM 345 static int timer_suspend(struct sys_device *dev, pm_message_t state) 346 { 347 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 348 349 if (timer->suspend != NULL) 350 timer->suspend(); 351 352 return 0; 353 } 354 355 static int timer_resume(struct sys_device *dev) 356 { 357 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 358 359 if (timer->resume != NULL) 360 timer->resume(); 361 362 return 0; 363 } 364 #else 365 #define timer_suspend NULL 366 #define timer_resume NULL 367 #endif 368 369 static struct sysdev_class timer_sysclass = { 370 set_kset_name("timer"), 371 .suspend = timer_suspend, 372 .resume = timer_resume, 373 }; 374 375 #ifdef CONFIG_NO_IDLE_HZ 376 static int timer_dyn_tick_enable(void) 377 { 378 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 379 unsigned long flags; 380 int ret = -ENODEV; 381 382 if (dyn_tick) { 383 spin_lock_irqsave(&dyn_tick->lock, flags); 384 ret = 0; 385 if (!(dyn_tick->state & DYN_TICK_ENABLED)) { 386 ret = dyn_tick->enable(); 387 388 if (ret == 0) 389 dyn_tick->state |= DYN_TICK_ENABLED; 390 } 391 spin_unlock_irqrestore(&dyn_tick->lock, flags); 392 } 393 394 return ret; 395 } 396 397 static int timer_dyn_tick_disable(void) 398 { 399 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 400 unsigned long flags; 401 int ret = -ENODEV; 402 403 if (dyn_tick) { 404 spin_lock_irqsave(&dyn_tick->lock, flags); 405 ret = 0; 406 if (dyn_tick->state & DYN_TICK_ENABLED) { 407 ret = dyn_tick->disable(); 408 409 if (ret == 0) 410 dyn_tick->state &= ~DYN_TICK_ENABLED; 411 } 412 spin_unlock_irqrestore(&dyn_tick->lock, flags); 413 } 414 415 return ret; 416 } 417 418 /* 419 * Reprogram the system timer for at least the calculated time interval. 420 * This function should be called from the idle thread with IRQs disabled, 421 * immediately before sleeping. 422 */ 423 void timer_dyn_reprogram(void) 424 { 425 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 426 unsigned long next, seq, flags; 427 428 if (!dyn_tick) 429 return; 430 431 spin_lock_irqsave(&dyn_tick->lock, flags); 432 if (dyn_tick->state & DYN_TICK_ENABLED) { 433 next = next_timer_interrupt(); 434 do { 435 seq = read_seqbegin(&xtime_lock); 436 dyn_tick->reprogram(next - jiffies); 437 } while (read_seqretry(&xtime_lock, seq)); 438 } 439 spin_unlock_irqrestore(&dyn_tick->lock, flags); 440 } 441 442 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf) 443 { 444 return sprintf(buf, "%i\n", 445 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1); 446 } 447 448 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf, 449 size_t count) 450 { 451 unsigned int enable = simple_strtoul(buf, NULL, 2); 452 453 if (enable) 454 timer_dyn_tick_enable(); 455 else 456 timer_dyn_tick_disable(); 457 458 return count; 459 } 460 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick); 461 462 /* 463 * dyntick=enable|disable 464 */ 465 static char dyntick_str[4] __initdata = ""; 466 467 static int __init dyntick_setup(char *str) 468 { 469 if (str) 470 strlcpy(dyntick_str, str, sizeof(dyntick_str)); 471 return 1; 472 } 473 474 __setup("dyntick=", dyntick_setup); 475 #endif 476 477 static int __init timer_init_sysfs(void) 478 { 479 int ret = sysdev_class_register(&timer_sysclass); 480 if (ret == 0) { 481 system_timer->dev.cls = &timer_sysclass; 482 ret = sysdev_register(&system_timer->dev); 483 } 484 485 #ifdef CONFIG_NO_IDLE_HZ 486 if (ret == 0 && system_timer->dyn_tick) { 487 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick); 488 489 /* 490 * Turn on dynamic tick after calibrate delay 491 * for correct bogomips 492 */ 493 if (ret == 0 && dyntick_str[0] == 'e') 494 ret = timer_dyn_tick_enable(); 495 } 496 #endif 497 498 return ret; 499 } 500 501 device_initcall(timer_init_sysfs); 502 503 void __init time_init(void) 504 { 505 #ifndef CONFIG_GENERIC_TIME 506 if (system_timer->offset == NULL) 507 system_timer->offset = dummy_gettimeoffset; 508 #endif 509 system_timer->init(); 510 511 #ifdef CONFIG_NO_IDLE_HZ 512 if (system_timer->dyn_tick) 513 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED; 514 #endif 515 } 516 517