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 #ifndef CONFIG_GENERIC_TIME
  51 void do_gettimeofday(struct timeval *tv)
  52 {
  53         unsigned long seq;
  54         unsigned long usec, sec;
  55
  56         do {
  57                 seq = read_seqbegin(&xtime_lock);
  58                 usec = get_timer_offset();
  59                 sec = xtime.tv_sec;
  60                 usec += xtime.tv_nsec / 1000;
  61         } while (read_seqretry(&xtime_lock, seq));
  62
  63         while (usec >= 1000000) {
  64                 usec -= 1000000;
  65                 sec++;
  66         }
  67
  68         tv->tv_sec = sec;
  69         tv->tv_usec = usec;
  70 }
  71 EXPORT_SYMBOL(do_gettimeofday);
  72
  73 int do_settimeofday(struct timespec *tv)
  74 {
  75         time_t wtm_sec, sec = tv->tv_sec;
  76         long wtm_nsec, nsec = tv->tv_nsec;
  77
  78         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  79                 return -EINVAL;
  80
  81         write_seqlock_irq(&xtime_lock);
  82         /*
  83          * This is revolting. We need to set "xtime" correctly. However, the
  84          * value in this location is the value at the most recent update of
  85          * wall time.  Discover what correction gettimeofday() would have
  86          * made, and then undo it!
  87          */
  88         nsec -= 1000 * get_timer_offset();
  89
  90         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  91         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
  92
  93         set_normalized_timespec(&xtime, sec, nsec);
  94         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
  95
  96         ntp_clear();
  97         write_sequnlock_irq(&xtime_lock);
  98         clock_was_set();
  99
 100         return 0;
 101 }
 102 EXPORT_SYMBOL(do_settimeofday);
 103 #endif /* !CONFIG_GENERIC_TIME */
 104
 105 /* last time the RTC clock got updated */
 106 static long last_rtc_update;
 107
 108 /*
 109  * handle_timer_tick() needs to keep up the real-time clock,
 110  * as well as call the "do_timer()" routine every clocktick
 111  */
 112 void handle_timer_tick(struct pt_regs *regs)
 113 {
 114         do_timer(1);
 115 #ifndef CONFIG_SMP
 116         update_process_times(user_mode(regs));
 117 #endif
 118         profile_tick(CPU_PROFILING, regs);
 119
 120 #ifdef CONFIG_HEARTBEAT
 121         if (sh_mv.mv_heartbeat != NULL)
 122                 sh_mv.mv_heartbeat();
 123 #endif
 124
 125         /*
 126          * If we have an externally synchronized Linux clock, then update
 127          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 128          * called as close as possible to 500 ms before the new second starts.
 129          */
 130         if (ntp_synced() &&
 131             xtime.tv_sec > last_rtc_update + 660 &&
 132             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 133             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 134                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 135                         last_rtc_update = xtime.tv_sec;
 136                 else
 137                         /* do it again in 60s */
 138                         last_rtc_update = xtime.tv_sec - 600;
 139         }
 140 }
 141
 142 #ifdef CONFIG_PM
 143 int timer_suspend(struct sys_device *dev, pm_message_t state)
 144 {
 145         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 146
 147         sys_timer->ops->stop();
 148
 149         return 0;
 150 }
 151
 152 int timer_resume(struct sys_device *dev)
 153 {
 154         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 155
 156         sys_timer->ops->start();
 157
 158         return 0;
 159 }
 160 #else
 161 #define timer_suspend NULL
 162 #define timer_resume NULL
 163 #endif
 164
 165 static struct sysdev_class timer_sysclass = {
 166         set_kset_name("timer"),
 167         .suspend = timer_suspend,
 168         .resume  = timer_resume,
 169 };
 170
 171 static int __init timer_init_sysfs(void)
 172 {
 173         int ret = sysdev_class_register(&timer_sysclass);
 174         if (ret != 0)
 175                 return ret;
 176
 177         sys_timer->dev.cls = &timer_sysclass;
 178         return sysdev_register(&sys_timer->dev);
 179 }
 180 device_initcall(timer_init_sysfs);
 181
 182 void (*board_time_init)(void);
 183
 184 void __init time_init(void)
 185 {
 186         if (board_time_init)
 187                 board_time_init();
 188
 189         clk_init();
 190
 191         rtc_sh_get_time(&xtime);
 192         set_normalized_timespec(&wall_to_monotonic,
 193                                 -xtime.tv_sec, -xtime.tv_nsec);
 194
 195         /*
 196          * Find the timer to use as the system timer, it will be
 197          * initialized for us.
 198          */
 199         sys_timer = get_sys_timer();
 200         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 201
 202 #if defined(CONFIG_SH_KGDB)
 203         /*
 204          * Set up kgdb as requested. We do it here because the serial
 205          * init uses the timer vars we just set up for figuring baud.
 206          */
 207         kgdb_init();
 208 #endif
 209 }