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/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/profile.h>
  17 #include <asm/clock.h>
  18 #include <asm/rtc.h>
  19 #include <asm/timer.h>
  20 #include <asm/kgdb.h>
  21
  22 extern unsigned long wall_jiffies;
  23 struct sys_timer *sys_timer;
  24
  25 /* Move this somewhere more sensible.. */
  26 DEFINE_SPINLOCK(rtc_lock);
  27 EXPORT_SYMBOL(rtc_lock);
  28
  29 /* XXX: Can we initialize this in a routine somewhere?  Dreamcast doesn't want
  30  * these routines anywhere... */
  31 #ifdef CONFIG_SH_RTC
  32 void (*rtc_get_time)(struct timespec *) = sh_rtc_gettimeofday;
  33 int (*rtc_set_time)(const time_t) = sh_rtc_settimeofday;
  34 #else
  35 void (*rtc_get_time)(struct timespec *);
  36 int (*rtc_set_time)(const time_t);
  37 #endif
  38
  39 /*
  40  * Scheduler clock - returns current time in nanosec units.
  41  */
  42 unsigned long long __attribute__ ((weak)) sched_clock(void)
  43 {
  44         return (unsigned long long)jiffies * (1000000000 / HZ);
  45 }
  46
  47 void do_gettimeofday(struct timeval *tv)
  48 {
  49         unsigned long seq;
  50         unsigned long usec, sec;
  51         unsigned long lost;
  52
  53         do {
  54                 seq = read_seqbegin(&xtime_lock);
  55                 usec = get_timer_offset();
  56
  57                 lost = jiffies - wall_jiffies;
  58                 if (lost)
  59                         usec += lost * (1000000 / HZ);
  60
  61                 sec = xtime.tv_sec;
  62                 usec += xtime.tv_nsec / 1000;
  63         } while (read_seqretry(&xtime_lock, seq));
  64
  65         while (usec >= 1000000) {
  66                 usec -= 1000000;
  67                 sec++;
  68         }
  69
  70         tv->tv_sec = sec;
  71         tv->tv_usec = usec;
  72 }
  73
  74 EXPORT_SYMBOL(do_gettimeofday);
  75
  76 int do_settimeofday(struct timespec *tv)
  77 {
  78         time_t wtm_sec, sec = tv->tv_sec;
  79         long wtm_nsec, nsec = tv->tv_nsec;
  80
  81         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  82                 return -EINVAL;
  83
  84         write_seqlock_irq(&xtime_lock);
  85         /*
  86          * This is revolting. We need to set "xtime" correctly. However, the
  87          * value in this location is the value at the most recent update of
  88          * wall time.  Discover what correction gettimeofday() would have
  89          * made, and then undo it!
  90          */
  91         nsec -= 1000 * (get_timer_offset() +
  92                                 (jiffies - wall_jiffies) * (1000000 / HZ));
  93
  94         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  95         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
  96
  97         set_normalized_timespec(&xtime, sec, nsec);
  98         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
  99
 100         ntp_clear();
 101         write_sequnlock_irq(&xtime_lock);
 102         clock_was_set();
 103
 104         return 0;
 105 }
 106
 107 EXPORT_SYMBOL(do_settimeofday);
 108
 109 /* last time the RTC clock got updated */
 110 static long last_rtc_update;
 111
 112 /*
 113  * handle_timer_tick() needs to keep up the real-time clock,
 114  * as well as call the "do_timer()" routine every clocktick
 115  */
 116 void handle_timer_tick(struct pt_regs *regs)
 117 {
 118         do_timer(regs);
 119 #ifndef CONFIG_SMP
 120         update_process_times(user_mode(regs));
 121 #endif
 122         profile_tick(CPU_PROFILING, regs);
 123
 124 #ifdef CONFIG_HEARTBEAT
 125         if (sh_mv.mv_heartbeat != NULL)
 126                 sh_mv.mv_heartbeat();
 127 #endif
 128
 129         /*
 130          * If we have an externally synchronized Linux clock, then update
 131          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 132          * called as close as possible to 500 ms before the new second starts.
 133          */
 134         if (ntp_synced() &&
 135             xtime.tv_sec > last_rtc_update + 660 &&
 136             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 137             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 138                 if (rtc_set_time(xtime.tv_sec) == 0)
 139                         last_rtc_update = xtime.tv_sec;
 140                 else
 141                         /* do it again in 60s */
 142                         last_rtc_update = xtime.tv_sec - 600;
 143         }
 144 }
 145
 146 static struct sysdev_class timer_sysclass = {
 147         set_kset_name("timer"),
 148 };
 149
 150 static int __init timer_init_sysfs(void)
 151 {
 152         int ret = sysdev_class_register(&timer_sysclass);
 153         if (ret != 0)
 154                 return ret;
 155
 156         sys_timer->dev.cls = &timer_sysclass;
 157         return sysdev_register(&sys_timer->dev);
 158 }
 159
 160 device_initcall(timer_init_sysfs);
 161
 162 void (*board_time_init)(void);
 163
 164 void __init time_init(void)
 165 {
 166         if (board_time_init)
 167                 board_time_init();
 168
 169         clk_init();
 170
 171         if (rtc_get_time) {
 172                 rtc_get_time(&xtime);
 173         } else {
 174                 xtime.tv_sec = mktime(2000, 1, 1, 0, 0, 0);
 175                 xtime.tv_nsec = 0;
 176         }
 177
 178         set_normalized_timespec(&wall_to_monotonic,
 179                                 -xtime.tv_sec, -xtime.tv_nsec);
 180
 181         /*
 182          * Find the timer to use as the system timer, it will be
 183          * initialized for us.
 184          */
 185         sys_timer = get_sys_timer();
 186         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 187
 188 #if defined(CONFIG_SH_KGDB)
 189         /*
 190          * Set up kgdb as requested. We do it here because the serial
 191          * init uses the timer vars we just set up for figuring baud.
 192          */
 193         kgdb_init();
 194 #endif
 195 }