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 <linux/timex.h>
  17 #include <linux/sched.h>
  18 #include <asm/clock.h>
  19 #include <asm/rtc.h>
  20 #include <asm/timer.h>
  21 #include <asm/kgdb.h>
  22
  23 struct sys_timer *sys_timer;
  24
  25 /* Move this somewhere more sensible.. */
  26 DEFINE_SPINLOCK(rtc_lock);
  27 EXPORT_SYMBOL(rtc_lock);
  28
  29 /* Dummy RTC ops */
  30 static void null_rtc_get_time(struct timespec *tv)
  31 {
  32         tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
  33         tv->tv_nsec = 0;
  34 }
  35
  36 static int null_rtc_set_time(const time_t secs)
  37 {
  38         return 0;
  39 }
  40
  41 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
  42 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
  43
  44 /*
  45  * Scheduler clock - returns current time in nanosec units.
  46  */
  47 unsigned long long __attribute__ ((weak)) sched_clock(void)
  48 {
  49         return (unsigned long long)jiffies * (1000000000 / HZ);
  50 }
  51
  52 #ifndef CONFIG_GENERIC_TIME
  53 void do_gettimeofday(struct timeval *tv)
  54 {
  55         unsigned long flags;
  56         unsigned long seq;
  57         unsigned long usec, sec;
  58
  59         do {
  60                 /*
  61                  * Turn off IRQs when grabbing xtime_lock, so that
  62                  * the sys_timer get_offset code doesn't have to handle it.
  63                  */
  64                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
  65                 usec = get_timer_offset();
  66                 sec = xtime.tv_sec;
  67                 usec += xtime.tv_nsec / NSEC_PER_USEC;
  68         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
  69
  70         while (usec >= 1000000) {
  71                 usec -= 1000000;
  72                 sec++;
  73         }
  74
  75         tv->tv_sec = sec;
  76         tv->tv_usec = usec;
  77 }
  78 EXPORT_SYMBOL(do_gettimeofday);
  79
  80 int do_settimeofday(struct timespec *tv)
  81 {
  82         time_t wtm_sec, sec = tv->tv_sec;
  83         long wtm_nsec, nsec = tv->tv_nsec;
  84
  85         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  86                 return -EINVAL;
  87
  88         write_seqlock_irq(&xtime_lock);
  89         /*
  90          * This is revolting. We need to set "xtime" correctly. However, the
  91          * value in this location is the value at the most recent update of
  92          * wall time.  Discover what correction gettimeofday() would have
  93          * made, and then undo it!
  94          */
  95         nsec -= get_timer_offset() * NSEC_PER_USEC;
  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 #endif /* !CONFIG_GENERIC_TIME */
 111
 112 /* last time the RTC clock got updated */
 113 static long last_rtc_update;
 114
 115 /*
 116  * handle_timer_tick() needs to keep up the real-time clock,
 117  * as well as call the "do_timer()" routine every clocktick
 118  */
 119 void handle_timer_tick(void)
 120 {
 121         do_timer(1);
 122 #ifndef CONFIG_SMP
 123         update_process_times(user_mode(get_irq_regs()));
 124 #endif
 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          * If we have an externally synchronized Linux clock, then update
 135          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 136          * called as close as possible to 500 ms before the new second starts.
 137          */
 138         if (ntp_synced() &&
 139             xtime.tv_sec > last_rtc_update + 660 &&
 140             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 141             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 142                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 143                         last_rtc_update = xtime.tv_sec;
 144                 else
 145                         /* do it again in 60s */
 146                         last_rtc_update = xtime.tv_sec - 600;
 147         }
 148 }
 149
 150 #ifdef CONFIG_PM
 151 int timer_suspend(struct sys_device *dev, pm_message_t state)
 152 {
 153         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 154
 155         sys_timer->ops->stop();
 156
 157         return 0;
 158 }
 159
 160 int timer_resume(struct sys_device *dev)
 161 {
 162         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 163
 164         sys_timer->ops->start();
 165
 166         return 0;
 167 }
 168 #else
 169 #define timer_suspend NULL
 170 #define timer_resume NULL
 171 #endif
 172
 173 static struct sysdev_class timer_sysclass = {
 174         set_kset_name("timer"),
 175         .suspend = timer_suspend,
 176         .resume  = timer_resume,
 177 };
 178
 179 #ifdef CONFIG_NO_IDLE_HZ
 180 static int timer_dyn_tick_enable(void)
 181 {
 182         struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
 183         unsigned long flags;
 184         int ret = -ENODEV;
 185
 186         if (dyn_tick) {
 187                 spin_lock_irqsave(&dyn_tick->lock, flags);
 188                 ret = 0;
 189                 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
 190                         ret = dyn_tick->enable();
 191
 192                         if (ret == 0)
 193                                 dyn_tick->state |= DYN_TICK_ENABLED;
 194                 }
 195                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 196         }
 197
 198         return ret;
 199 }
 200
 201 static int timer_dyn_tick_disable(void)
 202 {
 203         struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
 204         unsigned long flags;
 205         int ret = -ENODEV;
 206
 207         if (dyn_tick) {
 208                 spin_lock_irqsave(&dyn_tick->lock, flags);
 209                 ret = 0;
 210                 if (dyn_tick->state & DYN_TICK_ENABLED) {
 211                         ret = dyn_tick->disable();
 212
 213                         if (ret == 0)
 214                                 dyn_tick->state &= ~DYN_TICK_ENABLED;
 215                 }
 216                 spin_unlock_irqrestore(&dyn_tick->lock, flags);
 217         }
 218
 219         return ret;
 220 }
 221
 222 /*
 223  * Reprogram the system timer for at least the calculated time interval.
 224  * This function should be called from the idle thread with IRQs disabled,
 225  * immediately before sleeping.
 226  */
 227 void timer_dyn_reprogram(void)
 228 {
 229         struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
 230         unsigned long next, seq, flags;
 231
 232         if (!dyn_tick)
 233                 return;
 234
 235         spin_lock_irqsave(&dyn_tick->lock, flags);
 236         if (dyn_tick->state & DYN_TICK_ENABLED) {
 237                 next = next_timer_interrupt();
 238                 do {
 239                         seq = read_seqbegin(&xtime_lock);
 240                         dyn_tick->reprogram(next - jiffies);
 241                 } while (read_seqretry(&xtime_lock, seq));
 242         }
 243         spin_unlock_irqrestore(&dyn_tick->lock, flags);
 244 }
 245
 246 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
 247 {
 248         return sprintf(buf, "%i\n",
 249                        (sys_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
 250 }
 251
 252 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
 253                                   size_t count)
 254 {
 255         unsigned int enable = simple_strtoul(buf, NULL, 2);
 256
 257         if (enable)
 258                 timer_dyn_tick_enable();
 259         else
 260                 timer_dyn_tick_disable();
 261
 262         return count;
 263 }
 264 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
 265
 266 /*
 267  * dyntick=enable|disable
 268  */
 269 static char dyntick_str[4] __initdata = "";
 270
 271 static int __init dyntick_setup(char *str)
 272 {
 273         if (str)
 274                 strlcpy(dyntick_str, str, sizeof(dyntick_str));
 275         return 1;
 276 }
 277
 278 __setup("dyntick=", dyntick_setup);
 279 #endif
 280
 281 static int __init timer_init_sysfs(void)
 282 {
 283         int ret = sysdev_class_register(&timer_sysclass);
 284         if (ret != 0)
 285                 return ret;
 286
 287         sys_timer->dev.cls = &timer_sysclass;
 288         ret = sysdev_register(&sys_timer->dev);
 289
 290 #ifdef CONFIG_NO_IDLE_HZ
 291         if (ret == 0 && sys_timer->dyn_tick) {
 292                 ret = sysdev_create_file(&sys_timer->dev, &attr_dyn_tick);
 293
 294                 /*
 295                  * Turn on dynamic tick after calibrate delay
 296                  * for correct bogomips
 297                  */
 298                 if (ret == 0 && dyntick_str[0] == 'e')
 299                         ret = timer_dyn_tick_enable();
 300         }
 301 #endif
 302
 303         return ret;
 304 }
 305 device_initcall(timer_init_sysfs);
 306
 307 void (*board_time_init)(void);
 308
 309 void __init time_init(void)
 310 {
 311         if (board_time_init)
 312                 board_time_init();
 313
 314         clk_init();
 315
 316         rtc_sh_get_time(&xtime);
 317         set_normalized_timespec(&wall_to_monotonic,
 318                                 -xtime.tv_sec, -xtime.tv_nsec);
 319
 320         /*
 321          * Find the timer to use as the system timer, it will be
 322          * initialized for us.
 323          */
 324         sys_timer = get_sys_timer();
 325         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 326
 327 #ifdef CONFIG_NO_IDLE_HZ
 328         if (sys_timer->dyn_tick)
 329                 spin_lock_init(&sys_timer->dyn_tick->lock);
 330 #endif
 331
 332 #if defined(CONFIG_SH_KGDB)
 333         /*
 334          * Set up kgdb as requested. We do it here because the serial
 335          * init uses the timer vars we just set up for figuring baud.
 336          */
 337         kgdb_init();
 338 #endif
 339 }