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         /*
 129          * Here we are in the timer irq handler. We just have irqs locally
 130          * disabled but we don't know if the timer_bh is running on the other
 131          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
 132          * the irq version of write_lock because as just said we have irq
 133          * locally disabled. -arca
 134          */
 135         write_seqlock(&xtime_lock);
 136         do_timer(1);
 137
 138         /*
 139          * If we have an externally synchronized Linux clock, then update
 140          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 141          * called as close as possible to 500 ms before the new second starts.
 142          */
 143         if (ntp_synced() &&
 144             xtime.tv_sec > last_rtc_update + 660 &&
 145             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 146             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 147                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 148                         last_rtc_update = xtime.tv_sec;
 149                 else
 150                         /* do it again in 60s */
 151                         last_rtc_update = xtime.tv_sec - 600;
 152         }
 153         write_sequnlock(&xtime_lock);
 154
 155 #ifndef CONFIG_SMP
 156         update_process_times(user_mode(get_irq_regs()));
 157 #endif
 158 }
 159 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 160
 161 #ifdef CONFIG_PM
 162 int timer_suspend(struct sys_device *dev, pm_message_t state)
 163 {
 164         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 165
 166         sys_timer->ops->stop();
 167
 168         return 0;
 169 }
 170
 171 int timer_resume(struct sys_device *dev)
 172 {
 173         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 174
 175         sys_timer->ops->start();
 176
 177         return 0;
 178 }
 179 #else
 180 #define timer_suspend NULL
 181 #define timer_resume NULL
 182 #endif
 183
 184 static struct sysdev_class timer_sysclass = {
 185         .name    = "timer",
 186         .suspend = timer_suspend,
 187         .resume  = timer_resume,
 188 };
 189
 190 static int __init timer_init_sysfs(void)
 191 {
 192         int ret = sysdev_class_register(&timer_sysclass);
 193         if (ret != 0)
 194                 return ret;
 195
 196         sys_timer->dev.cls = &timer_sysclass;
 197         return sysdev_register(&sys_timer->dev);
 198 }
 199 device_initcall(timer_init_sysfs);
 200
 201 void (*board_time_init)(void);
 202
 203 /*
 204  * Shamelessly based on the MIPS and Sparc64 work.
 205  */
 206 static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
 207 unsigned long sh_hpt_frequency = 0;
 208
 209 #define NSEC_PER_CYC_SHIFT      10
 210
 211 static struct clocksource clocksource_sh = {
 212         .name           = "SuperH",
 213         .rating         = 200,
 214         .mask           = CLOCKSOURCE_MASK(32),
 215         .read           = null_hpt_read,
 216         .shift          = 16,
 217         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 218 };
 219
 220 static void __init init_sh_clocksource(void)
 221 {
 222         if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
 223                 return;
 224
 225         clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
 226                                                   clocksource_sh.shift);
 227
 228         timer_ticks_per_nsec_quotient =
 229                 clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);
 230
 231         clocksource_register(&clocksource_sh);
 232 }
 233
 234 #ifdef CONFIG_GENERIC_TIME
 235 unsigned long long sched_clock(void)
 236 {
 237         unsigned long long ticks = clocksource_sh.read();
 238         return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
 239 }
 240 #endif
 241
 242 void __init time_init(void)
 243 {
 244         if (board_time_init)
 245                 board_time_init();
 246
 247         clk_init();
 248
 249         rtc_sh_get_time(&xtime);
 250         set_normalized_timespec(&wall_to_monotonic,
 251                                 -xtime.tv_sec, -xtime.tv_nsec);
 252
 253 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 254         local_timer_setup(smp_processor_id());
 255 #endif
 256
 257         /*
 258          * Find the timer to use as the system timer, it will be
 259          * initialized for us.
 260          */
 261         sys_timer = get_sys_timer();
 262         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 263
 264
 265         if (sys_timer->ops->read)
 266                 clocksource_sh.read = sys_timer->ops->read;
 267
 268         init_sh_clocksource();
 269
 270         if (sh_hpt_frequency)
 271                 printk("Using %lu.%03lu MHz high precision timer.\n",
 272                        ((sh_hpt_frequency + 500) / 1000) / 1000,
 273                        ((sh_hpt_frequency + 500) / 1000) % 1000);
 274
 275 }