arch/sh/kernel/time_32.c

   1 /*
   2  *  arch/sh/kernel/time_32.c
   3  *
   4  *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
   5  *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
   6  *  Copyright (C) 2002 - 2008  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 <linux/timex.h>
  17 #include <linux/sched.h>
  18 #include <linux/clockchips.h>
  19 #include <linux/mc146818rtc.h>  /* for rtc_lock */
  20 #include <linux/smp.h>
  21 #include <asm/clock.h>
  22 #include <asm/rtc.h>
  23 #include <asm/timer.h>
  24 #include <asm/kgdb.h>
  25
  26 struct sys_timer *sys_timer;
  27
  28 /* Move this somewhere more sensible.. */
  29 DEFINE_SPINLOCK(rtc_lock);
  30 EXPORT_SYMBOL(rtc_lock);
  31
  32 /* Dummy RTC ops */
  33 static void null_rtc_get_time(struct timespec *tv)
  34 {
  35         tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
  36         tv->tv_nsec = 0;
  37 }
  38
  39 static int null_rtc_set_time(const time_t secs)
  40 {
  41         return 0;
  42 }
  43
  44 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
  45 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
  46
  47 #ifndef CONFIG_GENERIC_TIME
  48 void do_gettimeofday(struct timeval *tv)
  49 {
  50         unsigned long flags;
  51         unsigned long seq;
  52         unsigned long usec, sec;
  53
  54         do {
  55                 /*
  56                  * Turn off IRQs when grabbing xtime_lock, so that
  57                  * the sys_timer get_offset code doesn't have to handle it.
  58                  */
  59                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
  60                 usec = get_timer_offset();
  61                 sec = xtime.tv_sec;
  62                 usec += xtime.tv_nsec / NSEC_PER_USEC;
  63         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
  64
  65         while (usec >= 1000000) {
  66                 usec -= 1000000;
  67                 sec++;
  68         }
  69
  70         tv->tv_sec = sec;
  71         tv->tv_usec = usec;
  72 }
  73 EXPORT_SYMBOL(do_gettimeofday);
  74
  75 int do_settimeofday(struct timespec *tv)
  76 {
  77         time_t wtm_sec, sec = tv->tv_sec;
  78         long wtm_nsec, nsec = tv->tv_nsec;
  79
  80         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  81                 return -EINVAL;
  82
  83         write_seqlock_irq(&xtime_lock);
  84         /*
  85          * This is revolting. We need to set "xtime" correctly. However, the
  86          * value in this location is the value at the most recent update of
  87          * wall time.  Discover what correction gettimeofday() would have
  88          * made, and then undo it!
  89          */
  90         nsec -= get_timer_offset() * NSEC_PER_USEC;
  91
  92         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  93         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
  94
  95         set_normalized_timespec(&xtime, sec, nsec);
  96         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
  97
  98         ntp_clear();
  99         write_sequnlock_irq(&xtime_lock);
 100         clock_was_set();
 101
 102         return 0;
 103 }
 104 EXPORT_SYMBOL(do_settimeofday);
 105 #endif /* !CONFIG_GENERIC_TIME */
 106
 107 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 108 /* last time the RTC clock got updated */
 109 static long last_rtc_update;
 110
 111 /*
 112  * handle_timer_tick() needs to keep up the real-time clock,
 113  * as well as call the "do_timer()" routine every clocktick
 114  */
 115 void handle_timer_tick(void)
 116 {
 117         if (current->pid)
 118                 profile_tick(CPU_PROFILING);
 119
 120         /*
 121          * Here we are in the timer irq handler. We just have irqs locally
 122          * disabled but we don't know if the timer_bh is running on the other
 123          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
 124          * the irq version of write_lock because as just said we have irq
 125          * locally disabled. -arca
 126          */
 127         write_seqlock(&xtime_lock);
 128         do_timer(1);
 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_sh_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         write_sequnlock(&xtime_lock);
 146
 147 #ifndef CONFIG_SMP
 148         update_process_times(user_mode(get_irq_regs()));
 149 #endif
 150 }
 151 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 152
 153 #ifdef CONFIG_PM
 154 int timer_suspend(struct sys_device *dev, pm_message_t state)
 155 {
 156         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 157
 158         sys_timer->ops->stop();
 159
 160         return 0;
 161 }
 162
 163 int timer_resume(struct sys_device *dev)
 164 {
 165         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 166
 167         sys_timer->ops->start();
 168
 169         return 0;
 170 }
 171 #else
 172 #define timer_suspend NULL
 173 #define timer_resume NULL
 174 #endif
 175
 176 static struct sysdev_class timer_sysclass = {
 177         .name    = "timer",
 178         .suspend = timer_suspend,
 179         .resume  = timer_resume,
 180 };
 181
 182 static int __init timer_init_sysfs(void)
 183 {
 184         int ret = sysdev_class_register(&timer_sysclass);
 185         if (ret != 0)
 186                 return ret;
 187
 188         sys_timer->dev.cls = &timer_sysclass;
 189         return sysdev_register(&sys_timer->dev);
 190 }
 191 device_initcall(timer_init_sysfs);
 192
 193 void (*board_time_init)(void);
 194
 195 struct clocksource clocksource_sh = {
 196         .name           = "SuperH",
 197 };
 198
 199 #ifdef CONFIG_GENERIC_TIME
 200 unsigned long long sched_clock(void)
 201 {
 202         unsigned long long cycles;
 203
 204         /* jiffies based sched_clock if no clocksource is installed */
 205         if (!clocksource_sh.rating)
 206                 return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
 207
 208         cycles = clocksource_sh.read();
 209         return cyc2ns(&clocksource_sh, cycles);
 210 }
 211 #endif
 212
 213 void __init time_init(void)
 214 {
 215         if (board_time_init)
 216                 board_time_init();
 217
 218         clk_init();
 219
 220         rtc_sh_get_time(&xtime);
 221         set_normalized_timespec(&wall_to_monotonic,
 222                                 -xtime.tv_sec, -xtime.tv_nsec);
 223
 224 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 225         local_timer_setup(smp_processor_id());
 226 #endif
 227
 228         /*
 229          * Find the timer to use as the system timer, it will be
 230          * initialized for us.
 231          */
 232         sys_timer = get_sys_timer();
 233         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 234 }