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 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, const char *buf, size_t size)
134 {
135 int ret = -EINVAL, len = strcspn(buf, " ");
136
137 if (len > 0 && buf[len] == '\0')
138 len--;
139
140 if (strncmp(buf, "claim", len) == 0) {
141 leds_event(led_claim);
142 ret = size;
143 } else if (strncmp(buf, "release", len) == 0) {
144 leds_event(led_release);
145 ret = size;
146 } else {
147 int i;
148
149 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
150 if (strlen(evt_names[i].name) != len ||
151 strncmp(buf, evt_names[i].name, len) != 0)
152 continue;
153 if (strncmp(buf+len, " on", 3) == 0) {
154 leds_event(evt_names[i].on);
155 ret = size;
156 } else if (strncmp(buf+len, " off", 4) == 0) {
157 leds_event(evt_names[i].off);
158 ret = size;
159 }
160 break;
161 }
162 }
163 return ret;
164 }
165
166 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
167
168 static int leds_suspend(struct sys_device *dev, pm_message_t state)
169 {
170 leds_event(led_stop);
171 return 0;
172 }
173
174 static int leds_resume(struct sys_device *dev)
175 {
176 leds_event(led_start);
177 return 0;
178 }
179
180 static int leds_shutdown(struct sys_device *dev)
181 {
182 leds_event(led_halted);
183 return 0;
184 }
185
186 static struct sysdev_class leds_sysclass = {
187 .name = "leds",
188 .shutdown = leds_shutdown,
189 .suspend = leds_suspend,
190 .resume = leds_resume,
191 };
192
193 static struct sys_device leds_device = {
194 .id = 0,
195 .cls = &leds_sysclass,
196 };
197
198 static int __init leds_init(void)
199 {
200 int ret;
201 ret = sysdev_class_register(&leds_sysclass);
202 if (ret == 0)
203 ret = sysdev_register(&leds_device);
204 if (ret == 0)
205 ret = sysdev_create_file(&leds_device, &attr_event);
206 return ret;
207 }
208
209 device_initcall(leds_init);
210
211 EXPORT_SYMBOL(leds_event);
212 #endif
213
214 #ifdef CONFIG_LEDS_TIMER
215 static inline void do_leds(void)
216 {
217 static unsigned int count = HZ/2;
218
219 if (--count == 0) {
220 count = HZ/2;
221 leds_event(led_timer);
222 }
223 }
224 #else
225 #define do_leds()
226 #endif
227
228 #ifndef CONFIG_GENERIC_TIME
229 void do_gettimeofday(struct timeval *tv)
230 {
231 unsigned long flags;
232 unsigned long seq;
233 unsigned long usec, sec;
234
235 do {
236 seq = read_seqbegin_irqsave(&xtime_lock, flags);
237 usec = system_timer->offset();
238 sec = xtime.tv_sec;
239 usec += xtime.tv_nsec / 1000;
240 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
241
242 /* usec may have gone up a lot: be safe */
243 while (usec >= 1000000) {
244 usec -= 1000000;
245 sec++;
246 }
247
248 tv->tv_sec = sec;
249 tv->tv_usec = usec;
250 }
251
252 EXPORT_SYMBOL(do_gettimeofday);
253
254 int do_settimeofday(struct timespec *tv)
255 {
256 time_t wtm_sec, sec = tv->tv_sec;
257 long wtm_nsec, nsec = tv->tv_nsec;
258
259 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
260 return -EINVAL;
261
262 write_seqlock_irq(&xtime_lock);
263 /*
264 * This is revolting. We need to set "xtime" correctly. However, the
265 * value in this location is the value at the most recent update of
266 * wall time. Discover what correction gettimeofday() would have
267 * done, and then undo it!
268 */
269 nsec -= system_timer->offset() * NSEC_PER_USEC;
270
271 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
272 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
273
274 set_normalized_timespec(&xtime, sec, nsec);
275 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
276
277 ntp_clear();
278 write_sequnlock_irq(&xtime_lock);
279 clock_was_set();
280 return 0;
281 }
282
283 EXPORT_SYMBOL(do_settimeofday);
284 #endif /* !CONFIG_GENERIC_TIME */
285
286 /**
287 * save_time_delta - Save the offset between system time and RTC time
288 * @delta: pointer to timespec to store delta
289 * @rtc: pointer to timespec for current RTC time
290 *
291 * Return a delta between the system time and the RTC time, such
292 * that system time can be restored later with restore_time_delta()
293 */
294 void save_time_delta(struct timespec *delta, struct timespec *rtc)
295 {
296 set_normalized_timespec(delta,
297 xtime.tv_sec - rtc->tv_sec,
298 xtime.tv_nsec - rtc->tv_nsec);
299 }
300 EXPORT_SYMBOL(save_time_delta);
301
302 /**
303 * restore_time_delta - Restore the current system time
304 * @delta: delta returned by save_time_delta()
305 * @rtc: pointer to timespec for current RTC time
306 */
307 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
308 {
309 struct timespec ts;
310
311 set_normalized_timespec(&ts,
312 delta->tv_sec + rtc->tv_sec,
313 delta->tv_nsec + rtc->tv_nsec);
314
315 do_settimeofday(&ts);
316 }
317 EXPORT_SYMBOL(restore_time_delta);
318
319 #ifndef CONFIG_GENERIC_CLOCKEVENTS
320 /*
321 * Kernel system timer support.
322 */
323 void timer_tick(void)
324 {
325 profile_tick(CPU_PROFILING);
326 do_leds();
327 do_set_rtc();
328 write_seqlock(&xtime_lock);
329 do_timer(1);
330 write_sequnlock(&xtime_lock);
331 #ifndef CONFIG_SMP
332 update_process_times(user_mode(get_irq_regs()));
333 #endif
334 }
335 #endif
336
337 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
338 static int timer_suspend(struct sys_device *dev, pm_message_t state)
339 {
340 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
341
342 if (timer->suspend != NULL)
343 timer->suspend();
344
345 return 0;
346 }
347
348 static int timer_resume(struct sys_device *dev)
349 {
350 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
351
352 if (timer->resume != NULL)
353 timer->resume();
354
355 return 0;
356 }
357 #else
358 #define timer_suspend NULL
359 #define timer_resume NULL
360 #endif
361
362 static struct sysdev_class timer_sysclass = {
363 .name = "timer",
364 .suspend = timer_suspend,
365 .resume = timer_resume,
366 };
367
368 #ifdef CONFIG_NO_IDLE_HZ
369 static int timer_dyn_tick_enable(void)
370 {
371 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
372 unsigned long flags;
373 int ret = -ENODEV;
374
375 if (dyn_tick) {
376 spin_lock_irqsave(&dyn_tick->lock, flags);
377 ret = 0;
378 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
379 ret = dyn_tick->enable();
380
381 if (ret == 0)
382 dyn_tick->state |= DYN_TICK_ENABLED;
383 }
384 spin_unlock_irqrestore(&dyn_tick->lock, flags);
385 }
386
387 return ret;
388 }
389
390 static int timer_dyn_tick_disable(void)
391 {
392 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
393 unsigned long flags;
394 int ret = -ENODEV;
395
396 if (dyn_tick) {
397 spin_lock_irqsave(&dyn_tick->lock, flags);
398 ret = 0;
399 if (dyn_tick->state & DYN_TICK_ENABLED) {
400 ret = dyn_tick->disable();
401
402 if (ret == 0)
403 dyn_tick->state &= ~DYN_TICK_ENABLED;
404 }
405 spin_unlock_irqrestore(&dyn_tick->lock, flags);
406 }
407
408 return ret;
409 }
410
411 /*
412 * Reprogram the system timer for at least the calculated time interval.
413 * This function should be called from the idle thread with IRQs disabled,
414 * immediately before sleeping.
415 */
416 void timer_dyn_reprogram(void)
417 {
418 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
419 unsigned long next, seq, flags;
420
421 if (!dyn_tick)
422 return;
423
424 spin_lock_irqsave(&dyn_tick->lock, flags);
425 if (dyn_tick->state & DYN_TICK_ENABLED) {
426 next = next_timer_interrupt();
427 do {
428 seq = read_seqbegin(&xtime_lock);
429 dyn_tick->reprogram(next - jiffies);
430 } while (read_seqretry(&xtime_lock, seq));
431 }
432 spin_unlock_irqrestore(&dyn_tick->lock, flags);
433 }
434
435 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
436 {
437 return sprintf(buf, "%i\n",
438 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
439 }
440
441 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
442 size_t count)
443 {
444 unsigned int enable = simple_strtoul(buf, NULL, 2);
445
446 if (enable)
447 timer_dyn_tick_enable();
448 else
449 timer_dyn_tick_disable();
450
451 return count;
452 }
453 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
454
455 /*
456 * dyntick=enable|disable
457 */
458 static char dyntick_str[4] __initdata = "";
459
460 static int __init dyntick_setup(char *str)
461 {
462 if (str)
463 strlcpy(dyntick_str, str, sizeof(dyntick_str));
464 return 1;
465 }
466
467 __setup("dyntick=", dyntick_setup);
468 #endif
469
470 static int __init timer_init_sysfs(void)
471 {
472 int ret = sysdev_class_register(&timer_sysclass);
473 if (ret == 0) {
474 system_timer->dev.cls = &timer_sysclass;
475 ret = sysdev_register(&system_timer->dev);
476 }
477
478 #ifdef CONFIG_NO_IDLE_HZ
479 if (ret == 0 && system_timer->dyn_tick) {
480 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
481
482 /*
483 * Turn on dynamic tick after calibrate delay
484 * for correct bogomips
485 */
486 if (ret == 0 && dyntick_str[0] == 'e')
487 ret = timer_dyn_tick_enable();
488 }
489 #endif
490
491 return ret;
492 }
493
494 device_initcall(timer_init_sysfs);
495
496 void __init time_init(void)
497 {
498 #ifndef CONFIG_GENERIC_TIME
499 if (system_timer->offset == NULL)
500 system_timer->offset = dummy_gettimeoffset;
501 #endif
502 system_timer->init();
503
504 #ifdef CONFIG_NO_IDLE_HZ
505 if (system_timer->dyn_tick)
506 spin_lock_init(&system_timer->dyn_tick->lock);
507 #endif
508 }
509
510
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