2 * arch/sh/kernel/time.c
4 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
5 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
6 * Copyright (C) 2002, 2003, 2004, 2005 Paul Mundt
7 * Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org>
9 * Some code taken from i386 version.
10 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
13 #include <linux/config.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/profile.h>
18 #include <asm/clock.h>
20 #include <asm/timer.h>
23 extern unsigned long wall_jiffies;
24 struct sys_timer *sys_timer;
26 /* Move this somewhere more sensible.. */
27 DEFINE_SPINLOCK(rtc_lock);
28 EXPORT_SYMBOL(rtc_lock);
30 /* XXX: Can we initialize this in a routine somewhere? Dreamcast doesn't want
31 * these routines anywhere... */
33 void (*rtc_get_time)(struct timespec *) = sh_rtc_gettimeofday;
34 int (*rtc_set_time)(const time_t) = sh_rtc_settimeofday;
36 void (*rtc_get_time)(struct timespec *);
37 int (*rtc_set_time)(const time_t);
41 * Scheduler clock - returns current time in nanosec units.
43 unsigned long long __attribute__ ((weak)) sched_clock(void)
45 return (unsigned long long)jiffies * (1000000000 / HZ);
48 void do_gettimeofday(struct timeval *tv)
51 unsigned long usec, sec;
55 seq = read_seqbegin(&xtime_lock);
56 usec = get_timer_offset();
58 lost = jiffies - wall_jiffies;
60 usec += lost * (1000000 / HZ);
63 usec += xtime.tv_nsec / 1000;
64 } while (read_seqretry(&xtime_lock, seq));
66 while (usec >= 1000000) {
75 EXPORT_SYMBOL(do_gettimeofday);
77 int do_settimeofday(struct timespec *tv)
79 time_t wtm_sec, sec = tv->tv_sec;
80 long wtm_nsec, nsec = tv->tv_nsec;
82 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
85 write_seqlock_irq(&xtime_lock);
87 * This is revolting. We need to set "xtime" correctly. However, the
88 * value in this location is the value at the most recent update of
89 * wall time. Discover what correction gettimeofday() would have
90 * made, and then undo it!
92 nsec -= 1000 * (get_timer_offset() +
93 (jiffies - wall_jiffies) * (1000000 / HZ));
95 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
96 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
98 set_normalized_timespec(&xtime, sec, nsec);
99 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
102 write_sequnlock_irq(&xtime_lock);
108 EXPORT_SYMBOL(do_settimeofday);
110 /* last time the RTC clock got updated */
111 static long last_rtc_update;
114 * handle_timer_tick() needs to keep up the real-time clock,
115 * as well as call the "do_timer()" routine every clocktick
117 void handle_timer_tick(struct pt_regs *regs)
121 update_process_times(user_mode(regs));
123 profile_tick(CPU_PROFILING, regs);
125 #ifdef CONFIG_HEARTBEAT
126 if (sh_mv.mv_heartbeat != NULL)
127 sh_mv.mv_heartbeat();
131 * If we have an externally synchronized Linux clock, then update
132 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
133 * called as close as possible to 500 ms before the new second starts.
136 xtime.tv_sec > last_rtc_update + 660 &&
137 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
138 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
139 if (rtc_set_time(xtime.tv_sec) == 0)
140 last_rtc_update = xtime.tv_sec;
142 /* do it again in 60s */
143 last_rtc_update = xtime.tv_sec - 600;
147 static struct sysdev_class timer_sysclass = {
148 set_kset_name("timer"),
151 static int __init timer_init_sysfs(void)
153 int ret = sysdev_class_register(&timer_sysclass);
157 sys_timer->dev.cls = &timer_sysclass;
158 return sysdev_register(&sys_timer->dev);
161 device_initcall(timer_init_sysfs);
163 void (*board_time_init)(void);
165 void __init time_init(void)
173 rtc_get_time(&xtime);
175 xtime.tv_sec = mktime(2000, 1, 1, 0, 0, 0);
179 set_normalized_timespec(&wall_to_monotonic,
180 -xtime.tv_sec, -xtime.tv_nsec);
183 * Find the timer to use as the system timer, it will be
184 * initialized for us.
186 sys_timer = get_sys_timer();
187 printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
189 #if defined(CONFIG_SH_KGDB)
191 * Set up kgdb as requested. We do it here because the serial
192 * init uses the timer vars we just set up for figuring baud.