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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/kernel/time.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm/kernel/time.c')
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diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
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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/hardware.h>
33#include <asm/io.h>
34#include <asm/irq.h>
35#include <asm/leds.h>
36#include <asm/thread_info.h>
37#include <asm/mach/time.h>
38
39u64 jiffies_64 = INITIAL_JIFFIES;
40
41EXPORT_SYMBOL(jiffies_64);
42
43/*
44 * Our system timer.
45 */
46struct sys_timer *system_timer;
47
48extern unsigned long wall_jiffies;
49
50/* this needs a better home */
51DEFINE_SPINLOCK(rtc_lock);
52
53#ifdef CONFIG_SA1100_RTC_MODULE
54EXPORT_SYMBOL(rtc_lock);
55#endif
56
57/* change this if you have some constant time drift */
58#define USECS_PER_JIFFY (1000000/HZ)
59
60#ifdef CONFIG_SMP
61unsigned long profile_pc(struct pt_regs *regs)
62{
63 unsigned long fp, pc = instruction_pointer(regs);
64
65 if (in_lock_functions(pc)) {
66 fp = regs->ARM_fp;
67 pc = pc_pointer(((unsigned long *)fp)[-1]);
68 }
69
70 return pc;
71}
72EXPORT_SYMBOL(profile_pc);
73#endif
74
75/*
76 * hook for setting the RTC's idea of the current time.
77 */
78int (*set_rtc)(void);
79
80static unsigned long dummy_gettimeoffset(void)
81{
82 return 0;
83}
84
85/*
86 * Scheduler clock - returns current time in nanosec units.
87 * This is the default implementation. Sub-architecture
88 * implementations can override this.
89 */
90unsigned long long __attribute__((weak)) sched_clock(void)
91{
92 return (unsigned long long)jiffies * (1000000000 / HZ);
93}
94
95static unsigned long next_rtc_update;
96
97/*
98 * If we have an externally synchronized linux clock, then update
99 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
100 * called as close as possible to 500 ms before the new second
101 * starts.
102 */
103static inline void do_set_rtc(void)
104{
105 if (time_status & STA_UNSYNC || set_rtc == NULL)
106 return;
107
108 if (next_rtc_update &&
109 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
110 return;
111
112 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
113 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
114 return;
115
116 if (set_rtc())
117 /*
118 * rtc update failed. Try again in 60s
119 */
120 next_rtc_update = xtime.tv_sec + 60;
121 else
122 next_rtc_update = xtime.tv_sec + 660;
123}
124
125#ifdef CONFIG_LEDS
126
127static void dummy_leds_event(led_event_t evt)
128{
129}
130
131void (*leds_event)(led_event_t) = dummy_leds_event;
132
133struct leds_evt_name {
134 const char name[8];
135 int on;
136 int off;
137};
138
139static const struct leds_evt_name evt_names[] = {
140 { "amber", led_amber_on, led_amber_off },
141 { "blue", led_blue_on, led_blue_off },
142 { "green", led_green_on, led_green_off },
143 { "red", led_red_on, led_red_off },
144};
145
146static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
147{
148 int ret = -EINVAL, len = strcspn(buf, " ");
149
150 if (len > 0 && buf[len] == '\0')
151 len--;
152
153 if (strncmp(buf, "claim", len) == 0) {
154 leds_event(led_claim);
155 ret = size;
156 } else if (strncmp(buf, "release", len) == 0) {
157 leds_event(led_release);
158 ret = size;
159 } else {
160 int i;
161
162 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
163 if (strlen(evt_names[i].name) != len ||
164 strncmp(buf, evt_names[i].name, len) != 0)
165 continue;
166 if (strncmp(buf+len, " on", 3) == 0) {
167 leds_event(evt_names[i].on);
168 ret = size;
169 } else if (strncmp(buf+len, " off", 4) == 0) {
170 leds_event(evt_names[i].off);
171 ret = size;
172 }
173 break;
174 }
175 }
176 return ret;
177}
178
179static SYSDEV_ATTR(event, 0200, NULL, leds_store);
180
181static int leds_suspend(struct sys_device *dev, pm_message_t state)
182{
183 leds_event(led_stop);
184 return 0;
185}
186
187static int leds_resume(struct sys_device *dev)
188{
189 leds_event(led_start);
190 return 0;
191}
192
193static int leds_shutdown(struct sys_device *dev)
194{
195 leds_event(led_halted);
196 return 0;
197}
198
199static struct sysdev_class leds_sysclass = {
200 set_kset_name("leds"),
201 .shutdown = leds_shutdown,
202 .suspend = leds_suspend,
203 .resume = leds_resume,
204};
205
206static struct sys_device leds_device = {
207 .id = 0,
208 .cls = &leds_sysclass,
209};
210
211static int __init leds_init(void)
212{
213 int ret;
214 ret = sysdev_class_register(&leds_sysclass);
215 if (ret == 0)
216 ret = sysdev_register(&leds_device);
217 if (ret == 0)
218 ret = sysdev_create_file(&leds_device, &attr_event);
219 return ret;
220}
221
222device_initcall(leds_init);
223
224EXPORT_SYMBOL(leds_event);
225#endif
226
227#ifdef CONFIG_LEDS_TIMER
228static inline void do_leds(void)
229{
230 static unsigned int count = 50;
231
232 if (--count == 0) {
233 count = 50;
234 leds_event(led_timer);
235 }
236}
237#else
238#define do_leds()
239#endif
240
241void do_gettimeofday(struct timeval *tv)
242{
243 unsigned long flags;
244 unsigned long seq;
245 unsigned long usec, sec, lost;
246
247 do {
248 seq = read_seqbegin_irqsave(&xtime_lock, flags);
249 usec = system_timer->offset();
250
251 lost = jiffies - wall_jiffies;
252 if (lost)
253 usec += lost * USECS_PER_JIFFY;
254
255 sec = xtime.tv_sec;
256 usec += xtime.tv_nsec / 1000;
257 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
258
259 /* usec may have gone up a lot: be safe */
260 while (usec >= 1000000) {
261 usec -= 1000000;
262 sec++;
263 }
264
265 tv->tv_sec = sec;
266 tv->tv_usec = usec;
267}
268
269EXPORT_SYMBOL(do_gettimeofday);
270
271int do_settimeofday(struct timespec *tv)
272{
273 time_t wtm_sec, sec = tv->tv_sec;
274 long wtm_nsec, nsec = tv->tv_nsec;
275
276 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
277 return -EINVAL;
278
279 write_seqlock_irq(&xtime_lock);
280 /*
281 * This is revolting. We need to set "xtime" correctly. However, the
282 * value in this location is the value at the most recent update of
283 * wall time. Discover what correction gettimeofday() would have
284 * done, and then undo it!
285 */
286 nsec -= system_timer->offset() * NSEC_PER_USEC;
287 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
288
289 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
290 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
291
292 set_normalized_timespec(&xtime, sec, nsec);
293 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
294
295 time_adjust = 0; /* stop active adjtime() */
296 time_status |= STA_UNSYNC;
297 time_maxerror = NTP_PHASE_LIMIT;
298 time_esterror = NTP_PHASE_LIMIT;
299 write_sequnlock_irq(&xtime_lock);
300 clock_was_set();
301 return 0;
302}
303
304EXPORT_SYMBOL(do_settimeofday);
305
306/**
307 * save_time_delta - Save the offset between system time and RTC time
308 * @delta: pointer to timespec to store delta
309 * @rtc: pointer to timespec for current RTC time
310 *
311 * Return a delta between the system time and the RTC time, such
312 * that system time can be restored later with restore_time_delta()
313 */
314void save_time_delta(struct timespec *delta, struct timespec *rtc)
315{
316 set_normalized_timespec(delta,
317 xtime.tv_sec - rtc->tv_sec,
318 xtime.tv_nsec - rtc->tv_nsec);
319}
320EXPORT_SYMBOL(save_time_delta);
321
322/**
323 * restore_time_delta - Restore the current system time
324 * @delta: delta returned by save_time_delta()
325 * @rtc: pointer to timespec for current RTC time
326 */
327void restore_time_delta(struct timespec *delta, struct timespec *rtc)
328{
329 struct timespec ts;
330
331 set_normalized_timespec(&ts,
332 delta->tv_sec + rtc->tv_sec,
333 delta->tv_nsec + rtc->tv_nsec);
334
335 do_settimeofday(&ts);
336}
337EXPORT_SYMBOL(restore_time_delta);
338
339/*
340 * Kernel system timer support.
341 */
342void timer_tick(struct pt_regs *regs)
343{
344 profile_tick(CPU_PROFILING, regs);
345 do_leds();
346 do_set_rtc();
347 do_timer(regs);
348#ifndef CONFIG_SMP
349 update_process_times(user_mode(regs));
350#endif
351}
352
353#ifdef CONFIG_PM
354static int timer_suspend(struct sys_device *dev, pm_message_t state)
355{
356 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
357
358 if (timer->suspend != NULL)
359 timer->suspend();
360
361 return 0;
362}
363
364static int timer_resume(struct sys_device *dev)
365{
366 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
367
368 if (timer->resume != NULL)
369 timer->resume();
370
371 return 0;
372}
373#else
374#define timer_suspend NULL
375#define timer_resume NULL
376#endif
377
378static struct sysdev_class timer_sysclass = {
379 set_kset_name("timer"),
380 .suspend = timer_suspend,
381 .resume = timer_resume,
382};
383
384static int __init timer_init_sysfs(void)
385{
386 int ret = sysdev_class_register(&timer_sysclass);
387 if (ret == 0) {
388 system_timer->dev.cls = &timer_sysclass;
389 ret = sysdev_register(&system_timer->dev);
390 }
391 return ret;
392}
393
394device_initcall(timer_init_sysfs);
395
396void __init time_init(void)
397{
398 if (system_timer->offset == NULL)
399 system_timer->offset = dummy_gettimeoffset;
400 system_timer->init();
401}
402