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 /*
  45  * Null high precision timer functions for systems lacking one.
  46  */
  47 static cycle_t null_hpt_read(void)
  48 {
  49         return 0;
  50 }
  51
  52 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
  53 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
  54
  55 #ifndef CONFIG_GENERIC_TIME
  56 void do_gettimeofday(struct timeval *tv)
  57 {
  58         unsigned long flags;
  59         unsigned long seq;
  60         unsigned long usec, sec;
  61
  62         do {
  63                 /*
  64                  * Turn off IRQs when grabbing xtime_lock, so that
  65                  * the sys_timer get_offset code doesn't have to handle it.
  66                  */
  67                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
  68                 usec = get_timer_offset();
  69                 sec = xtime.tv_sec;
  70                 usec += xtime.tv_nsec / NSEC_PER_USEC;
  71         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
  72
  73         while (usec >= 1000000) {
  74                 usec -= 1000000;
  75                 sec++;
  76         }
  77
  78         tv->tv_sec = sec;
  79         tv->tv_usec = usec;
  80 }
  81 EXPORT_SYMBOL(do_gettimeofday);
  82
  83 int do_settimeofday(struct timespec *tv)
  84 {
  85         time_t wtm_sec, sec = tv->tv_sec;
  86         long wtm_nsec, nsec = tv->tv_nsec;
  87
  88         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  89                 return -EINVAL;
  90
  91         write_seqlock_irq(&xtime_lock);
  92         /*
  93          * This is revolting. We need to set "xtime" correctly. However, the
  94          * value in this location is the value at the most recent update of
  95          * wall time.  Discover what correction gettimeofday() would have
  96          * made, and then undo it!
  97          */
  98         nsec -= get_timer_offset() * NSEC_PER_USEC;
  99
 100         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 101         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 102
 103         set_normalized_timespec(&xtime, sec, nsec);
 104         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 105
 106         ntp_clear();
 107         write_sequnlock_irq(&xtime_lock);
 108         clock_was_set();
 109
 110         return 0;
 111 }
 112 EXPORT_SYMBOL(do_settimeofday);
 113 #endif /* !CONFIG_GENERIC_TIME */
 114
 115 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 116 /* last time the RTC clock got updated */
 117 static long last_rtc_update;
 118
 119 /*
 120  * handle_timer_tick() needs to keep up the real-time clock,
 121  * as well as call the "do_timer()" routine every clocktick
 122  */
 123 void handle_timer_tick(void)
 124 {
 125         if (current->pid)
 126                 profile_tick(CPU_PROFILING);
 127
 128 #ifdef CONFIG_HEARTBEAT
 129         if (sh_mv.mv_heartbeat != NULL)
 130                 sh_mv.mv_heartbeat();
 131 #endif
 132
 133         /*
 134          * Here we are in the timer irq handler. We just have irqs locally
 135          * disabled but we don't know if the timer_bh is running on the other
 136          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
 137          * the irq version of write_lock because as just said we have irq
 138          * locally disabled. -arca
 139          */
 140         write_seqlock(&xtime_lock);
 141         do_timer(1);
 142
 143         /*
 144          * If we have an externally synchronized Linux clock, then update
 145          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 146          * called as close as possible to 500 ms before the new second starts.
 147          */
 148         if (ntp_synced() &&
 149             xtime.tv_sec > last_rtc_update + 660 &&
 150             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 151             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 152                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 153                         last_rtc_update = xtime.tv_sec;
 154                 else
 155                         /* do it again in 60s */
 156                         last_rtc_update = xtime.tv_sec - 600;
 157         }
 158         write_sequnlock(&xtime_lock);
 159
 160 #ifndef CONFIG_SMP
 161         update_process_times(user_mode(get_irq_regs()));
 162 #endif
 163 }
 164 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 165
 166 #ifdef CONFIG_PM
 167 int timer_suspend(struct sys_device *dev, pm_message_t state)
 168 {
 169         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 170
 171         sys_timer->ops->stop();
 172
 173         return 0;
 174 }
 175
 176 int timer_resume(struct sys_device *dev)
 177 {
 178         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 179
 180         sys_timer->ops->start();
 181
 182         return 0;
 183 }
 184 #else
 185 #define timer_suspend NULL
 186 #define timer_resume NULL
 187 #endif
 188
 189 static struct sysdev_class timer_sysclass = {
 190         .name    = "timer",
 191         .suspend = timer_suspend,
 192         .resume  = timer_resume,
 193 };
 194
 195 static int __init timer_init_sysfs(void)
 196 {
 197         int ret = sysdev_class_register(&timer_sysclass);
 198         if (ret != 0)
 199                 return ret;
 200
 201         sys_timer->dev.cls = &timer_sysclass;
 202         return sysdev_register(&sys_timer->dev);
 203 }
 204 device_initcall(timer_init_sysfs);
 205
 206 void (*board_time_init)(void);
 207
 208 /*
 209  * Shamelessly based on the MIPS and Sparc64 work.
 210  */
 211 static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
 212 unsigned long sh_hpt_frequency = 0;
 213
 214 #define NSEC_PER_CYC_SHIFT      10
 215
 216 static struct clocksource clocksource_sh = {
 217         .name           = "SuperH",
 218         .rating         = 200,
 219         .mask           = CLOCKSOURCE_MASK(32),
 220         .read           = null_hpt_read,
 221         .shift          = 16,
 222         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 223 };
 224
 225 static void __init init_sh_clocksource(void)
 226 {
 227         if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
 228                 return;
 229
 230         clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
 231                                                   clocksource_sh.shift);
 232
 233         timer_ticks_per_nsec_quotient =
 234                 clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);
 235
 236         clocksource_register(&clocksource_sh);
 237 }
 238
 239 #ifdef CONFIG_GENERIC_TIME
 240 unsigned long long sched_clock(void)
 241 {
 242         unsigned long long ticks = clocksource_sh.read();
 243         return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
 244 }
 245 #endif
 246
 247 void __init time_init(void)
 248 {
 249         if (board_time_init)
 250                 board_time_init();
 251
 252         clk_init();
 253
 254         rtc_sh_get_time(&xtime);
 255         set_normalized_timespec(&wall_to_monotonic,
 256                                 -xtime.tv_sec, -xtime.tv_nsec);
 257
 258 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 259         local_timer_setup(smp_processor_id());
 260 #endif
 261
 262         /*
 263          * Find the timer to use as the system timer, it will be
 264          * initialized for us.
 265          */
 266         sys_timer = get_sys_timer();
 267         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 268
 269
 270         if (sys_timer->ops->read)
 271                 clocksource_sh.read = sys_timer->ops->read;
 272
 273         init_sh_clocksource();
 274
 275         if (sh_hpt_frequency)
 276                 printk("Using %lu.%03lu MHz high precision timer.\n",
 277                        ((sh_hpt_frequency + 500) / 1000) / 1000,
 278                        ((sh_hpt_frequency + 500) / 1000) % 1000);
 279
 280 #if defined(CONFIG_SH_KGDB)
 281         /*
 282          * Set up kgdb as requested. We do it here because the serial
 283          * init uses the timer vars we just set up for figuring baud.
 284          */
 285         kgdb_init();
 286 #endif
 287 }