2 * linux/arch/arm/kernel/time.c
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 * Modifications for ARM (C) 1994-2001 Russell King
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.
11 * This file contains the ARM-specific time handling details:
12 * reading the RTC at bootup, etc...
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/interrupt.h>
17 #include <linux/time.h>
18 #include <linux/init.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/timex.h>
22 #include <linux/errno.h>
23 #include <linux/profile.h>
24 #include <linux/sysdev.h>
25 #include <linux/timer.h>
26 #include <linux/irq.h>
28 #include <linux/mc146818rtc.h>
31 #include <asm/thread_info.h>
32 #include <asm/stacktrace.h>
33 #include <asm/mach/time.h>
38 struct sys_timer *system_timer;
40 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
41 /* this needs a better home */
42 DEFINE_SPINLOCK(rtc_lock);
44 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
45 EXPORT_SYMBOL(rtc_lock);
47 #endif /* pc-style 'CMOS' RTC support */
49 /* change this if you have some constant time drift */
50 #define USECS_PER_JIFFY (1000000/HZ)
53 unsigned long profile_pc(struct pt_regs *regs)
55 struct stackframe frame;
57 if (!in_lock_functions(regs->ARM_pc))
60 frame.fp = regs->ARM_fp;
61 frame.sp = regs->ARM_sp;
62 frame.lr = regs->ARM_lr;
63 frame.pc = regs->ARM_pc;
65 int ret = unwind_frame(&frame);
68 } while (in_lock_functions(frame.pc));
72 EXPORT_SYMBOL(profile_pc);
75 #ifndef CONFIG_GENERIC_TIME
76 static unsigned long dummy_gettimeoffset(void)
84 static void dummy_leds_event(led_event_t evt)
88 void (*leds_event)(led_event_t) = dummy_leds_event;
90 struct leds_evt_name {
96 static const struct leds_evt_name evt_names[] = {
97 { "amber", led_amber_on, led_amber_off },
98 { "blue", led_blue_on, led_blue_off },
99 { "green", led_green_on, led_green_off },
100 { "red", led_red_on, led_red_off },
103 static ssize_t leds_store(struct sys_device *dev,
104 struct sysdev_attribute *attr,
105 const char *buf, size_t size)
107 int ret = -EINVAL, len = strcspn(buf, " ");
109 if (len > 0 && buf[len] == '\0')
112 if (strncmp(buf, "claim", len) == 0) {
113 leds_event(led_claim);
115 } else if (strncmp(buf, "release", len) == 0) {
116 leds_event(led_release);
121 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
122 if (strlen(evt_names[i].name) != len ||
123 strncmp(buf, evt_names[i].name, len) != 0)
125 if (strncmp(buf+len, " on", 3) == 0) {
126 leds_event(evt_names[i].on);
128 } else if (strncmp(buf+len, " off", 4) == 0) {
129 leds_event(evt_names[i].off);
138 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
140 static int leds_suspend(struct sys_device *dev, pm_message_t state)
142 leds_event(led_stop);
146 static int leds_resume(struct sys_device *dev)
148 leds_event(led_start);
152 static int leds_shutdown(struct sys_device *dev)
154 leds_event(led_halted);
158 static struct sysdev_class leds_sysclass = {
160 .shutdown = leds_shutdown,
161 .suspend = leds_suspend,
162 .resume = leds_resume,
165 static struct sys_device leds_device = {
167 .cls = &leds_sysclass,
170 static int __init leds_init(void)
173 ret = sysdev_class_register(&leds_sysclass);
175 ret = sysdev_register(&leds_device);
177 ret = sysdev_create_file(&leds_device, &attr_event);
181 device_initcall(leds_init);
183 EXPORT_SYMBOL(leds_event);
186 #ifdef CONFIG_LEDS_TIMER
187 static inline void do_leds(void)
189 static unsigned int count = HZ/2;
193 leds_event(led_timer);
200 #ifndef CONFIG_GENERIC_TIME
201 void do_gettimeofday(struct timeval *tv)
205 unsigned long usec, sec;
208 seq = read_seqbegin_irqsave(&xtime_lock, flags);
209 usec = system_timer->offset();
211 usec += xtime.tv_nsec / 1000;
212 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
214 /* usec may have gone up a lot: be safe */
215 while (usec >= 1000000) {
224 EXPORT_SYMBOL(do_gettimeofday);
226 int do_settimeofday(struct timespec *tv)
228 time_t wtm_sec, sec = tv->tv_sec;
229 long wtm_nsec, nsec = tv->tv_nsec;
231 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
234 write_seqlock_irq(&xtime_lock);
236 * This is revolting. We need to set "xtime" correctly. However, the
237 * value in this location is the value at the most recent update of
238 * wall time. Discover what correction gettimeofday() would have
239 * done, and then undo it!
241 nsec -= system_timer->offset() * NSEC_PER_USEC;
243 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
244 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
246 set_normalized_timespec(&xtime, sec, nsec);
247 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
250 write_sequnlock_irq(&xtime_lock);
255 EXPORT_SYMBOL(do_settimeofday);
256 #endif /* !CONFIG_GENERIC_TIME */
258 #ifndef CONFIG_GENERIC_CLOCKEVENTS
260 * Kernel system timer support.
262 void timer_tick(void)
264 profile_tick(CPU_PROFILING);
266 write_seqlock(&xtime_lock);
268 write_sequnlock(&xtime_lock);
270 update_process_times(user_mode(get_irq_regs()));
275 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
276 static int timer_suspend(struct sys_device *dev, pm_message_t state)
278 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
280 if (timer->suspend != NULL)
286 static int timer_resume(struct sys_device *dev)
288 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
290 if (timer->resume != NULL)
296 #define timer_suspend NULL
297 #define timer_resume NULL
300 static struct sysdev_class timer_sysclass = {
302 .suspend = timer_suspend,
303 .resume = timer_resume,
306 static int __init timer_init_sysfs(void)
308 int ret = sysdev_class_register(&timer_sysclass);
310 system_timer->dev.cls = &timer_sysclass;
311 ret = sysdev_register(&system_timer->dev);
317 device_initcall(timer_init_sysfs);
319 void __init time_init(void)
321 #ifndef CONFIG_GENERIC_TIME
322 if (system_timer->offset == NULL)
323 system_timer->offset = dummy_gettimeoffset;
325 system_timer->init();