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, 2003, 2004, 2005  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
  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>
  19 #include <asm/rtc.h>
  20 #include <asm/timer.h>
  21 #include <asm/kgdb.h>
  22
  23 extern unsigned long wall_jiffies;
  24 struct sys_timer *sys_timer;
  25
  26 /* Move this somewhere more sensible.. */
  27 DEFINE_SPINLOCK(rtc_lock);
  28 EXPORT_SYMBOL(rtc_lock);
  29
  30 /* XXX: Can we initialize this in a routine somewhere?  Dreamcast doesn't want
  31  * these routines anywhere... */
  32 #ifdef CONFIG_SH_RTC
  33 void (*rtc_get_time)(struct timespec *) = sh_rtc_gettimeofday;
  34 int (*rtc_set_time)(const time_t) = sh_rtc_settimeofday;
  35 #else
  36 void (*rtc_get_time)(struct timespec *);
  37 int (*rtc_set_time)(const time_t);
  38 #endif
  39
  40 /*
  41  * Scheduler clock - returns current time in nanosec units.
  42  */
  43 unsigned long long __attribute__ ((weak)) sched_clock(void)
  44 {
  45         return (unsigned long long)jiffies * (1000000000 / HZ);
  46 }
  47
  48 void do_gettimeofday(struct timeval *tv)
  49 {
  50         unsigned long seq;
  51         unsigned long usec, sec;
  52         unsigned long lost;
  53
  54         do {
  55                 seq = read_seqbegin(&xtime_lock);
  56                 usec = get_timer_offset();
  57
  58                 lost = jiffies - wall_jiffies;
  59                 if (lost)
  60                         usec += lost * (1000000 / HZ);
  61
  62                 sec = xtime.tv_sec;
  63                 usec += xtime.tv_nsec / 1000;
  64         } while (read_seqretry(&xtime_lock, seq));
  65
  66         while (usec >= 1000000) {
  67                 usec -= 1000000;
  68                 sec++;
  69         }
  70
  71         tv->tv_sec = sec;
  72         tv->tv_usec = usec;
  73 }
  74
  75 EXPORT_SYMBOL(do_gettimeofday);
  76
  77 int do_settimeofday(struct timespec *tv)
  78 {
  79         time_t wtm_sec, sec = tv->tv_sec;
  80         long wtm_nsec, nsec = tv->tv_nsec;
  81
  82         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  83                 return -EINVAL;
  84
  85         write_seqlock_irq(&xtime_lock);
  86         /*
  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!
  91          */
  92         nsec -= 1000 * (get_timer_offset() +
  93                                 (jiffies - wall_jiffies) * (1000000 / HZ));
  94
  95         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  96         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
  97
  98         set_normalized_timespec(&xtime, sec, nsec);
  99         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 100
 101         ntp_clear();
 102         write_sequnlock_irq(&xtime_lock);
 103         clock_was_set();
 104
 105         return 0;
 106 }
 107
 108 EXPORT_SYMBOL(do_settimeofday);
 109
 110 /* last time the RTC clock got updated */
 111 static long last_rtc_update;
 112
 113 /*
 114  * handle_timer_tick() needs to keep up the real-time clock,
 115  * as well as call the "do_timer()" routine every clocktick
 116  */
 117 void handle_timer_tick(struct pt_regs *regs)
 118 {
 119         do_timer(regs);
 120 #ifndef CONFIG_SMP
 121         update_process_times(user_mode(regs));
 122 #endif
 123         profile_tick(CPU_PROFILING, regs);
 124
 125 #ifdef CONFIG_HEARTBEAT
 126         if (sh_mv.mv_heartbeat != NULL)
 127                 sh_mv.mv_heartbeat();
 128 #endif
 129
 130         /*
 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.
 134          */
 135         if (ntp_synced() &&
 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;
 141                 else
 142                         /* do it again in 60s */
 143                         last_rtc_update = xtime.tv_sec - 600;
 144         }
 145 }
 146
 147 static struct sysdev_class timer_sysclass = {
 148         set_kset_name("timer"),
 149 };
 150
 151 static int __init timer_init_sysfs(void)
 152 {
 153         int ret = sysdev_class_register(&timer_sysclass);
 154         if (ret != 0)
 155                 return ret;
 156
 157         sys_timer->dev.cls = &timer_sysclass;
 158         return sysdev_register(&sys_timer->dev);
 159 }
 160
 161 device_initcall(timer_init_sysfs);
 162
 163 void (*board_time_init)(void);
 164
 165 void __init time_init(void)
 166 {
 167         if (board_time_init)
 168                 board_time_init();
 169
 170         clk_init();
 171
 172         if (rtc_get_time) {
 173                 rtc_get_time(&xtime);
 174         } else {
 175                 xtime.tv_sec = mktime(2000, 1, 1, 0, 0, 0);
 176                 xtime.tv_nsec = 0;
 177         }
 178
 179         set_normalized_timespec(&wall_to_monotonic,
 180                                 -xtime.tv_sec, -xtime.tv_nsec);
 181
 182         /*
 183          * Find the timer to use as the system timer, it will be
 184          * initialized for us.
 185          */
 186         sys_timer = get_sys_timer();
 187         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 188
 189 #if defined(CONFIG_SH_KGDB)
 190         /*
 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.
 193          */
 194         kgdb_init();
 195 #endif
 196 }