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/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 extern unsigned long wall_jiffies; 42 43 /* this needs a better home */ 44 DEFINE_SPINLOCK(rtc_lock); 45 46 #ifdef CONFIG_SA1100_RTC_MODULE 47 EXPORT_SYMBOL(rtc_lock); 48 #endif 49 50 /* change this if you have some constant time drift */ 51 #define USECS_PER_JIFFY (1000000/HZ) 52 53 #ifdef CONFIG_SMP 54 unsigned long profile_pc(struct pt_regs *regs) 55 { 56 unsigned long fp, pc = instruction_pointer(regs); 57 58 if (in_lock_functions(pc)) { 59 fp = regs->ARM_fp; 60 pc = pc_pointer(((unsigned long *)fp)[-1]); 61 } 62 63 return pc; 64 } 65 EXPORT_SYMBOL(profile_pc); 66 #endif 67 68 /* 69 * hook for setting the RTC's idea of the current time. 70 */ 71 int (*set_rtc)(void); 72 73 static unsigned long dummy_gettimeoffset(void) 74 { 75 return 0; 76 } 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 = 50; 224 225 if (--count == 0) { 226 count = 50; 227 leds_event(led_timer); 228 } 229 } 230 #else 231 #define do_leds() 232 #endif 233 234 void do_gettimeofday(struct timeval *tv) 235 { 236 unsigned long flags; 237 unsigned long seq; 238 unsigned long usec, sec, lost; 239 240 do { 241 seq = read_seqbegin_irqsave(&xtime_lock, flags); 242 usec = system_timer->offset(); 243 244 lost = jiffies - wall_jiffies; 245 if (lost) 246 usec += lost * USECS_PER_JIFFY; 247 248 sec = xtime.tv_sec; 249 usec += xtime.tv_nsec / 1000; 250 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 251 252 /* usec may have gone up a lot: be safe */ 253 while (usec >= 1000000) { 254 usec -= 1000000; 255 sec++; 256 } 257 258 tv->tv_sec = sec; 259 tv->tv_usec = usec; 260 } 261 262 EXPORT_SYMBOL(do_gettimeofday); 263 264 int do_settimeofday(struct timespec *tv) 265 { 266 time_t wtm_sec, sec = tv->tv_sec; 267 long wtm_nsec, nsec = tv->tv_nsec; 268 269 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 270 return -EINVAL; 271 272 write_seqlock_irq(&xtime_lock); 273 /* 274 * This is revolting. We need to set "xtime" correctly. However, the 275 * value in this location is the value at the most recent update of 276 * wall time. Discover what correction gettimeofday() would have 277 * done, and then undo it! 278 */ 279 nsec -= system_timer->offset() * NSEC_PER_USEC; 280 nsec -= (jiffies - wall_jiffies) * TICK_NSEC; 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); 295 296 /** 297 * save_time_delta - Save the offset between system time and RTC time 298 * @delta: pointer to timespec to store delta 299 * @rtc: pointer to timespec for current RTC time 300 * 301 * Return a delta between the system time and the RTC time, such 302 * that system time can be restored later with restore_time_delta() 303 */ 304 void save_time_delta(struct timespec *delta, struct timespec *rtc) 305 { 306 set_normalized_timespec(delta, 307 xtime.tv_sec - rtc->tv_sec, 308 xtime.tv_nsec - rtc->tv_nsec); 309 } 310 EXPORT_SYMBOL(save_time_delta); 311 312 /** 313 * restore_time_delta - Restore the current system time 314 * @delta: delta returned by save_time_delta() 315 * @rtc: pointer to timespec for current RTC time 316 */ 317 void restore_time_delta(struct timespec *delta, struct timespec *rtc) 318 { 319 struct timespec ts; 320 321 set_normalized_timespec(&ts, 322 delta->tv_sec + rtc->tv_sec, 323 delta->tv_nsec + rtc->tv_nsec); 324 325 do_settimeofday(&ts); 326 } 327 EXPORT_SYMBOL(restore_time_delta); 328 329 /* 330 * Kernel system timer support. 331 */ 332 void timer_tick(struct pt_regs *regs) 333 { 334 profile_tick(CPU_PROFILING, regs); 335 do_leds(); 336 do_set_rtc(); 337 do_timer(regs); 338 #ifndef CONFIG_SMP 339 update_process_times(user_mode(regs)); 340 #endif 341 } 342 343 #ifdef CONFIG_PM 344 static int timer_suspend(struct sys_device *dev, pm_message_t state) 345 { 346 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 347 348 if (timer->suspend != NULL) 349 timer->suspend(); 350 351 return 0; 352 } 353 354 static int timer_resume(struct sys_device *dev) 355 { 356 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 357 358 if (timer->resume != NULL) 359 timer->resume(); 360 361 return 0; 362 } 363 #else 364 #define timer_suspend NULL 365 #define timer_resume NULL 366 #endif 367 368 static struct sysdev_class timer_sysclass = { 369 set_kset_name("timer"), 370 .suspend = timer_suspend, 371 .resume = timer_resume, 372 }; 373 374 #ifdef CONFIG_NO_IDLE_HZ 375 static int timer_dyn_tick_enable(void) 376 { 377 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 378 unsigned long flags; 379 int ret = -ENODEV; 380 381 if (dyn_tick) { 382 write_seqlock_irqsave(&xtime_lock, flags); 383 ret = 0; 384 if (!(dyn_tick->state & DYN_TICK_ENABLED)) { 385 ret = dyn_tick->enable(); 386 387 if (ret == 0) 388 dyn_tick->state |= DYN_TICK_ENABLED; 389 } 390 write_sequnlock_irqrestore(&xtime_lock, flags); 391 } 392 393 return ret; 394 } 395 396 static int timer_dyn_tick_disable(void) 397 { 398 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 399 unsigned long flags; 400 int ret = -ENODEV; 401 402 if (dyn_tick) { 403 write_seqlock_irqsave(&xtime_lock, flags); 404 ret = 0; 405 if (dyn_tick->state & DYN_TICK_ENABLED) { 406 ret = dyn_tick->disable(); 407 408 if (ret == 0) 409 dyn_tick->state &= ~DYN_TICK_ENABLED; 410 } 411 write_sequnlock_irqrestore(&xtime_lock, flags); 412 } 413 414 return ret; 415 } 416 417 /* 418 * Reprogram the system timer for at least the calculated time interval. 419 * This function should be called from the idle thread with IRQs disabled, 420 * immediately before sleeping. 421 */ 422 void timer_dyn_reprogram(void) 423 { 424 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 425 426 if (dyn_tick) { 427 write_seqlock(&xtime_lock); 428 if (dyn_tick->state & DYN_TICK_ENABLED) 429 dyn_tick->reprogram(next_timer_interrupt() - jiffies); 430 write_sequnlock(&xtime_lock); 431 } 432 } 433 434 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf) 435 { 436 return sprintf(buf, "%i\n", 437 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1); 438 } 439 440 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf, 441 size_t count) 442 { 443 unsigned int enable = simple_strtoul(buf, NULL, 2); 444 445 if (enable) 446 timer_dyn_tick_enable(); 447 else 448 timer_dyn_tick_disable(); 449 450 return count; 451 } 452 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick); 453 454 /* 455 * dyntick=enable|disable 456 */ 457 static char dyntick_str[4] __initdata = ""; 458 459 static int __init dyntick_setup(char *str) 460 { 461 if (str) 462 strlcpy(dyntick_str, str, sizeof(dyntick_str)); 463 return 1; 464 } 465 466 __setup("dyntick=", dyntick_setup); 467 #endif 468 469 static int __init timer_init_sysfs(void) 470 { 471 int ret = sysdev_class_register(&timer_sysclass); 472 if (ret == 0) { 473 system_timer->dev.cls = &timer_sysclass; 474 ret = sysdev_register(&system_timer->dev); 475 } 476 477 #ifdef CONFIG_NO_IDLE_HZ 478 if (ret == 0 && system_timer->dyn_tick) { 479 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick); 480 481 /* 482 * Turn on dynamic tick after calibrate delay 483 * for correct bogomips 484 */ 485 if (ret == 0 && dyntick_str[0] == 'e') 486 ret = timer_dyn_tick_enable(); 487 } 488 #endif 489 490 return ret; 491 } 492 493 device_initcall(timer_init_sysfs); 494 495 void __init time_init(void) 496 { 497 if (system_timer->offset == NULL) 498 system_timer->offset = dummy_gettimeoffset; 499 system_timer->init(); 500 } 501 502