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
profile_pc(struct pt_regs * regs)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
dummy_gettimeoffset(void)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 */
do_set_rtc(void)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
dummy_leds_event(led_event_t evt)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
leds_store(struct sys_device * dev,struct sysdev_attribute * attr,const char * buf,size_t size)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
leds_suspend(struct sys_device * dev,pm_message_t state)170 static int leds_suspend(struct sys_device *dev, pm_message_t state)
171 {
172 leds_event(led_stop);
173 return 0;
174 }
175
leds_resume(struct sys_device * dev)176 static int leds_resume(struct sys_device *dev)
177 {
178 leds_event(led_start);
179 return 0;
180 }
181
leds_shutdown(struct sys_device * dev)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
leds_init(void)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
do_leds(void)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
do_gettimeofday(struct timeval * tv)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
do_settimeofday(struct timespec * tv)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 */
save_time_delta(struct timespec * delta,struct timespec * rtc)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 */
restore_time_delta(struct timespec * delta,struct timespec * rtc)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 */
timer_tick(void)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)
timer_suspend(struct sys_device * dev,pm_message_t state)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
timer_resume(struct sys_device * dev)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
timer_init_sysfs(void)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
time_init(void)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
392