arch/sh/kernel/time.c

   1 /*
   2  *  arch/sh/kernel/time.c
   3  *
   4  *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
   5  *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
   6  *  Copyright (C) 2002 - 2006  Paul Mundt
   7  *  Copyright (C) 2002  M. R. Brown  <mrbrown@linux-sh.org>
   8  *
   9  *  Some code taken from i386 version.
  10  *    Copyright (C) 1991, 1992, 1995  Linus Torvalds
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/profile.h>
  16 #include <asm/clock.h>
  17 #include <asm/rtc.h>
  18 #include <asm/timer.h>
  19 #include <asm/kgdb.h>
  20
  21 struct sys_timer *sys_timer;
  22
  23 /* Move this somewhere more sensible.. */
  24 DEFINE_SPINLOCK(rtc_lock);
  25 EXPORT_SYMBOL(rtc_lock);
  26
  27 /* Dummy RTC ops */
  28 static void null_rtc_get_time(struct timespec *tv)
  29 {
  30         tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
  31         tv->tv_nsec = 0;
  32 }
  33
  34 static int null_rtc_set_time(const time_t secs)
  35 {
  36         return 0;
  37 }
  38
  39 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
  40 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
  41
  42 /*
  43  * Scheduler clock - returns current time in nanosec units.
  44  */
  45 unsigned long long __attribute__ ((weak)) sched_clock(void)
  46 {
  47         return (unsigned long long)jiffies * (1000000000 / HZ);
  48 }
  49
  50 void do_gettimeofday(struct timeval *tv)
  51 {
  52         unsigned long seq;
  53         unsigned long usec, sec;
  54
  55         do {
  56                 seq = read_seqbegin(&xtime_lock);
  57                 usec = get_timer_offset();
  58                 sec = xtime.tv_sec;
  59                 usec += xtime.tv_nsec / 1000;
  60         } while (read_seqretry(&xtime_lock, seq));
  61
  62         while (usec >= 1000000) {
  63                 usec -= 1000000;
  64                 sec++;
  65         }
  66
  67         tv->tv_sec = sec;
  68         tv->tv_usec = usec;
  69 }
  70 EXPORT_SYMBOL(do_gettimeofday);
  71
  72 int do_settimeofday(struct timespec *tv)
  73 {
  74         time_t wtm_sec, sec = tv->tv_sec;
  75         long wtm_nsec, nsec = tv->tv_nsec;
  76
  77         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  78                 return -EINVAL;
  79
  80         write_seqlock_irq(&xtime_lock);
  81         /*
  82          * This is revolting. We need to set "xtime" correctly. However, the
  83          * value in this location is the value at the most recent update of
  84          * wall time.  Discover what correction gettimeofday() would have
  85          * made, and then undo it!
  86          */
  87         nsec -= 1000 * get_timer_offset();
  88
  89         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  90         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
  91
  92         set_normalized_timespec(&xtime, sec, nsec);
  93         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
  94
  95         ntp_clear();
  96         write_sequnlock_irq(&xtime_lock);
  97         clock_was_set();
  98
  99         return 0;
 100 }
 101 EXPORT_SYMBOL(do_settimeofday);
 102
 103 /* last time the RTC clock got updated */
 104 static long last_rtc_update;
 105
 106 /*
 107  * handle_timer_tick() needs to keep up the real-time clock,
 108  * as well as call the "do_timer()" routine every clocktick
 109  */
 110 void handle_timer_tick(struct pt_regs *regs)
 111 {
 112         do_timer(1);
 113 #ifndef CONFIG_SMP
 114         update_process_times(user_mode(regs));
 115 #endif
 116         profile_tick(CPU_PROFILING, regs);
 117
 118 #ifdef CONFIG_HEARTBEAT
 119         if (sh_mv.mv_heartbeat != NULL)
 120                 sh_mv.mv_heartbeat();
 121 #endif
 122
 123         /*
 124          * If we have an externally synchronized Linux clock, then update
 125          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 126          * called as close as possible to 500 ms before the new second starts.
 127          */
 128         if (ntp_synced() &&
 129             xtime.tv_sec > last_rtc_update + 660 &&
 130             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 131             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 132                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 133                         last_rtc_update = xtime.tv_sec;
 134                 else
 135                         /* do it again in 60s */
 136                         last_rtc_update = xtime.tv_sec - 600;
 137         }
 138 }
 139
 140 #ifdef CONFIG_PM
 141 int timer_suspend(struct sys_device *dev, pm_message_t state)
 142 {
 143         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 144
 145         sys_timer->ops->stop();
 146
 147         return 0;
 148 }
 149
 150 int timer_resume(struct sys_device *dev)
 151 {
 152         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 153
 154         sys_timer->ops->start();
 155
 156         return 0;
 157 }
 158 #else
 159 #define timer_suspend NULL
 160 #define timer_resume NULL
 161 #endif
 162
 163 static struct sysdev_class timer_sysclass = {
 164         set_kset_name("timer"),
 165         .suspend = timer_suspend,
 166         .resume  = timer_resume,
 167 };
 168
 169 static int __init timer_init_sysfs(void)
 170 {
 171         int ret = sysdev_class_register(&timer_sysclass);
 172         if (ret != 0)
 173                 return ret;
 174
 175         sys_timer->dev.cls = &timer_sysclass;
 176         return sysdev_register(&sys_timer->dev);
 177 }
 178 device_initcall(timer_init_sysfs);
 179
 180 void (*board_time_init)(void);
 181
 182 void __init time_init(void)
 183 {
 184         if (board_time_init)
 185                 board_time_init();
 186
 187         clk_init();
 188
 189         rtc_sh_get_time(&xtime);
 190         set_normalized_timespec(&wall_to_monotonic,
 191                                 -xtime.tv_sec, -xtime.tv_nsec);
 192
 193         /*
 194          * Find the timer to use as the system timer, it will be
 195          * initialized for us.
 196          */
 197         sys_timer = get_sys_timer();
 198         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 199
 200 #if defined(CONFIG_SH_KGDB)
 201         /*
 202          * Set up kgdb as requested. We do it here because the serial
 203          * init uses the timer vars we just set up for figuring baud.
 204          */
 205         kgdb_init();
 206 #endif
 207 }