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 - 2007  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 <asm/clock.h>
  20 #include <asm/rtc.h>
  21 #include <asm/timer.h>
  22 #include <asm/kgdb.h>
  23
  24 struct sys_timer *sys_timer;
  25
  26 /* Move this somewhere more sensible.. */
  27 DEFINE_SPINLOCK(rtc_lock);
  28 EXPORT_SYMBOL(rtc_lock);
  29
  30 /* Dummy RTC ops */
  31 static void null_rtc_get_time(struct timespec *tv)
  32 {
  33         tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
  34         tv->tv_nsec = 0;
  35 }
  36
  37 static int null_rtc_set_time(const time_t secs)
  38 {
  39         return 0;
  40 }
  41
  42 /*
  43  * Null high precision timer functions for systems lacking one.
  44  */
  45 static cycle_t null_hpt_read(void)
  46 {
  47         return 0;
  48 }
  49
  50 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
  51 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
  52
  53 #ifndef CONFIG_GENERIC_TIME
  54 void do_gettimeofday(struct timeval *tv)
  55 {
  56         unsigned long flags;
  57         unsigned long seq;
  58         unsigned long usec, sec;
  59
  60         do {
  61                 /*
  62                  * Turn off IRQs when grabbing xtime_lock, so that
  63                  * the sys_timer get_offset code doesn't have to handle it.
  64                  */
  65                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
  66                 usec = get_timer_offset();
  67                 sec = xtime.tv_sec;
  68                 usec += xtime.tv_nsec / NSEC_PER_USEC;
  69         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
  70
  71         while (usec >= 1000000) {
  72                 usec -= 1000000;
  73                 sec++;
  74         }
  75
  76         tv->tv_sec = sec;
  77         tv->tv_usec = usec;
  78 }
  79 EXPORT_SYMBOL(do_gettimeofday);
  80
  81 int do_settimeofday(struct timespec *tv)
  82 {
  83         time_t wtm_sec, sec = tv->tv_sec;
  84         long wtm_nsec, nsec = tv->tv_nsec;
  85
  86         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  87                 return -EINVAL;
  88
  89         write_seqlock_irq(&xtime_lock);
  90         /*
  91          * This is revolting. We need to set "xtime" correctly. However, the
  92          * value in this location is the value at the most recent update of
  93          * wall time.  Discover what correction gettimeofday() would have
  94          * made, and then undo it!
  95          */
  96         nsec -= get_timer_offset() * NSEC_PER_USEC;
  97
  98         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
  99         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 100
 101         set_normalized_timespec(&xtime, sec, nsec);
 102         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 103
 104         ntp_clear();
 105         write_sequnlock_irq(&xtime_lock);
 106         clock_was_set();
 107
 108         return 0;
 109 }
 110 EXPORT_SYMBOL(do_settimeofday);
 111 #endif /* !CONFIG_GENERIC_TIME */
 112
 113 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 114 /* last time the RTC clock got updated */
 115 static long last_rtc_update;
 116
 117 /*
 118  * handle_timer_tick() needs to keep up the real-time clock,
 119  * as well as call the "do_timer()" routine every clocktick
 120  */
 121 void handle_timer_tick(void)
 122 {
 123         do_timer(1);
 124 #ifndef CONFIG_SMP
 125         update_process_times(user_mode(get_irq_regs()));
 126 #endif
 127         if (current->pid)
 128                 profile_tick(CPU_PROFILING);
 129
 130 #ifdef CONFIG_HEARTBEAT
 131         if (sh_mv.mv_heartbeat != NULL)
 132                 sh_mv.mv_heartbeat();
 133 #endif
 134
 135         /*
 136          * If we have an externally synchronized Linux clock, then update
 137          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 138          * called as close as possible to 500 ms before the new second starts.
 139          */
 140         if (ntp_synced() &&
 141             xtime.tv_sec > last_rtc_update + 660 &&
 142             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 143             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 144                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 145                         last_rtc_update = xtime.tv_sec;
 146                 else
 147                         /* do it again in 60s */
 148                         last_rtc_update = xtime.tv_sec - 600;
 149         }
 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         set_kset_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 /*
 196  * Shamelessly based on the MIPS and Sparc64 work.
 197  */
 198 static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
 199 unsigned long sh_hpt_frequency = 0;
 200
 201 #define NSEC_PER_CYC_SHIFT      10
 202
 203 struct clocksource clocksource_sh = {
 204         .name           = "SuperH",
 205         .rating         = 200,
 206         .mask           = CLOCKSOURCE_MASK(32),
 207         .read           = null_hpt_read,
 208         .shift          = 16,
 209         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 210 };
 211
 212 static void __init init_sh_clocksource(void)
 213 {
 214         if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
 215                 return;
 216
 217         clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
 218                                                   clocksource_sh.shift);
 219
 220         timer_ticks_per_nsec_quotient =
 221                 clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);
 222
 223         clocksource_register(&clocksource_sh);
 224 }
 225
 226 #ifdef CONFIG_GENERIC_TIME
 227 unsigned long long sched_clock(void)
 228 {
 229         unsigned long long ticks = clocksource_sh.read();
 230         return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
 231 }
 232 #endif
 233
 234 void __init time_init(void)
 235 {
 236         if (board_time_init)
 237                 board_time_init();
 238
 239         clk_init();
 240
 241         rtc_sh_get_time(&xtime);
 242         set_normalized_timespec(&wall_to_monotonic,
 243                                 -xtime.tv_sec, -xtime.tv_nsec);
 244
 245         /*
 246          * Find the timer to use as the system timer, it will be
 247          * initialized for us.
 248          */
 249         sys_timer = get_sys_timer();
 250         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 251
 252         if (sys_timer->ops->read)
 253                 clocksource_sh.read = sys_timer->ops->read;
 254
 255         init_sh_clocksource();
 256
 257         if (sh_hpt_frequency)
 258                 printk("Using %lu.%03lu MHz high precision timer.\n",
 259                        ((sh_hpt_frequency + 500) / 1000) / 1000,
 260                        ((sh_hpt_frequency + 500) / 1000) % 1000);
 261
 262 #if defined(CONFIG_SH_KGDB)
 263         /*
 264          * Set up kgdb as requested. We do it here because the serial
 265          * init uses the timer vars we just set up for figuring baud.
 266          */
 267         kgdb_init();
 268 #endif
 269 }