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 extern unsigned long wall_jiffies;
  22 struct sys_timer *sys_timer;
  23
  24 /* Move this somewhere more sensible.. */
  25 DEFINE_SPINLOCK(rtc_lock);
  26 EXPORT_SYMBOL(rtc_lock);
  27
  28 /* Dummy RTC ops */
  29 static void null_rtc_get_time(struct timespec *tv)
  30 {
  31         tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
  32         tv->tv_nsec = 0;
  33 }
  34
  35 static int null_rtc_set_time(const time_t secs)
  36 {
  37         return 0;
  38 }
  39
  40 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
  41 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
  42
  43 /*
  44  * Scheduler clock - returns current time in nanosec units.
  45  */
  46 unsigned long long __attribute__ ((weak)) sched_clock(void)
  47 {
  48         return (unsigned long long)jiffies * (1000000000 / HZ);
  49 }
  50
  51 void do_gettimeofday(struct timeval *tv)
  52 {
  53         unsigned long seq;
  54         unsigned long usec, sec;
  55         unsigned long lost;
  56
  57         do {
  58                 seq = read_seqbegin(&xtime_lock);
  59                 usec = get_timer_offset();
  60
  61                 lost = jiffies - wall_jiffies;
  62                 if (lost)
  63                         usec += lost * (1000000 / HZ);
  64
  65                 sec = xtime.tv_sec;
  66                 usec += xtime.tv_nsec / 1000;
  67         } while (read_seqretry(&xtime_lock, seq));
  68
  69         while (usec >= 1000000) {
  70                 usec -= 1000000;
  71                 sec++;
  72         }
  73
  74         tv->tv_sec = sec;
  75         tv->tv_usec = usec;
  76 }
  77 EXPORT_SYMBOL(do_gettimeofday);
  78
  79 int do_settimeofday(struct timespec *tv)
  80 {
  81         time_t wtm_sec, sec = tv->tv_sec;
  82         long wtm_nsec, nsec = tv->tv_nsec;
  83
  84         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  85                 return -EINVAL;
  86
  87         write_seqlock_irq(&xtime_lock);
  88         /*
  89          * This is revolting. We need to set "xtime" correctly. However, the
  90          * value in this location is the value at the most recent update of
  91          * wall time.  Discover what correction gettimeofday() would have
  92          * made, and then undo it!
  93          */
  94         nsec -= 1000 * (get_timer_offset() +
  95                                 (jiffies - wall_jiffies) * (1000000 / HZ));
  96
  97         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  98         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
  99
 100         set_normalized_timespec(&xtime, sec, nsec);
 101         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 102
 103         ntp_clear();
 104         write_sequnlock_irq(&xtime_lock);
 105         clock_was_set();
 106
 107         return 0;
 108 }
 109 EXPORT_SYMBOL(do_settimeofday);
 110
 111 /* last time the RTC clock got updated */
 112 static long last_rtc_update;
 113
 114 /*
 115  * handle_timer_tick() needs to keep up the real-time clock,
 116  * as well as call the "do_timer()" routine every clocktick
 117  */
 118 void handle_timer_tick(struct pt_regs *regs)
 119 {
 120         do_timer(1);
 121 #ifndef CONFIG_SMP
 122         update_process_times(user_mode(regs));
 123 #endif
 124         profile_tick(CPU_PROFILING, regs);
 125
 126 #ifdef CONFIG_HEARTBEAT
 127         if (sh_mv.mv_heartbeat != NULL)
 128                 sh_mv.mv_heartbeat();
 129 #endif
 130
 131         /*
 132          * If we have an externally synchronized Linux clock, then update
 133          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 134          * called as close as possible to 500 ms before the new second starts.
 135          */
 136         if (ntp_synced() &&
 137             xtime.tv_sec > last_rtc_update + 660 &&
 138             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 139             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 140                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 141                         last_rtc_update = xtime.tv_sec;
 142                 else
 143                         /* do it again in 60s */
 144                         last_rtc_update = xtime.tv_sec - 600;
 145         }
 146 }
 147
 148 #ifdef CONFIG_PM
 149 int timer_suspend(struct sys_device *dev, pm_message_t state)
 150 {
 151         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 152
 153         sys_timer->ops->stop();
 154
 155         return 0;
 156 }
 157
 158 int timer_resume(struct sys_device *dev)
 159 {
 160         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 161
 162         sys_timer->ops->start();
 163
 164         return 0;
 165 }
 166 #else
 167 #define timer_suspend NULL
 168 #define timer_resume NULL
 169 #endif
 170
 171 static struct sysdev_class timer_sysclass = {
 172         set_kset_name("timer"),
 173         .suspend = timer_suspend,
 174         .resume  = timer_resume,
 175 };
 176
 177 static int __init timer_init_sysfs(void)
 178 {
 179         int ret = sysdev_class_register(&timer_sysclass);
 180         if (ret != 0)
 181                 return ret;
 182
 183         sys_timer->dev.cls = &timer_sysclass;
 184         return sysdev_register(&sys_timer->dev);
 185 }
 186 device_initcall(timer_init_sysfs);
 187
 188 void (*board_time_init)(void);
 189
 190 void __init time_init(void)
 191 {
 192         if (board_time_init)
 193                 board_time_init();
 194
 195         clk_init();
 196
 197         rtc_sh_get_time(&xtime);
 198         set_normalized_timespec(&wall_to_monotonic,
 199                                 -xtime.tv_sec, -xtime.tv_nsec);
 200
 201         /*
 202          * Find the timer to use as the system timer, it will be
 203          * initialized for us.
 204          */
 205         sys_timer = get_sys_timer();
 206         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 207
 208 #if defined(CONFIG_SH_KGDB)
 209         /*
 210          * Set up kgdb as requested. We do it here because the serial
 211          * init uses the timer vars we just set up for figuring baud.
 212          */
 213         kgdb_init();
 214 #endif
 215 }