arch/sh/kernel/time_32.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         if (current->pid)
 124                 profile_tick(CPU_PROFILING);
 125
 126 #ifdef CONFIG_HEARTBEAT
 127         if (sh_mv.mv_heartbeat != NULL)
 128                 sh_mv.mv_heartbeat();
 129 #endif
 130
 131         /*
 132          * Here we are in the timer irq handler. We just have irqs locally
 133          * disabled but we don't know if the timer_bh is running on the other
 134          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
 135          * the irq version of write_lock because as just said we have irq
 136          * locally disabled. -arca
 137          */
 138         write_seqlock(&xtime_lock);
 139         do_timer(1);
 140
 141         /*
 142          * If we have an externally synchronized Linux clock, then update
 143          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 144          * called as close as possible to 500 ms before the new second starts.
 145          */
 146         if (ntp_synced() &&
 147             xtime.tv_sec > last_rtc_update + 660 &&
 148             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 149             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 150                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 151                         last_rtc_update = xtime.tv_sec;
 152                 else
 153                         /* do it again in 60s */
 154                         last_rtc_update = xtime.tv_sec - 600;
 155         }
 156         write_sequnlock(&xtime_lock);
 157
 158 #ifndef CONFIG_SMP
 159         update_process_times(user_mode(get_irq_regs()));
 160 #endif
 161 }
 162 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 163
 164 #ifdef CONFIG_PM
 165 int timer_suspend(struct sys_device *dev, pm_message_t state)
 166 {
 167         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 168
 169         sys_timer->ops->stop();
 170
 171         return 0;
 172 }
 173
 174 int timer_resume(struct sys_device *dev)
 175 {
 176         struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
 177
 178         sys_timer->ops->start();
 179
 180         return 0;
 181 }
 182 #else
 183 #define timer_suspend NULL
 184 #define timer_resume NULL
 185 #endif
 186
 187 static struct sysdev_class timer_sysclass = {
 188         .name    = "timer",
 189         .suspend = timer_suspend,
 190         .resume  = timer_resume,
 191 };
 192
 193 static int __init timer_init_sysfs(void)
 194 {
 195         int ret = sysdev_class_register(&timer_sysclass);
 196         if (ret != 0)
 197                 return ret;
 198
 199         sys_timer->dev.cls = &timer_sysclass;
 200         return sysdev_register(&sys_timer->dev);
 201 }
 202 device_initcall(timer_init_sysfs);
 203
 204 void (*board_time_init)(void);
 205
 206 /*
 207  * Shamelessly based on the MIPS and Sparc64 work.
 208  */
 209 static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
 210 unsigned long sh_hpt_frequency = 0;
 211
 212 #define NSEC_PER_CYC_SHIFT      10
 213
 214 struct clocksource clocksource_sh = {
 215         .name           = "SuperH",
 216         .rating         = 200,
 217         .mask           = CLOCKSOURCE_MASK(32),
 218         .read           = null_hpt_read,
 219         .shift          = 16,
 220         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 221 };
 222
 223 static void __init init_sh_clocksource(void)
 224 {
 225         if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
 226                 return;
 227
 228         clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
 229                                                   clocksource_sh.shift);
 230
 231         timer_ticks_per_nsec_quotient =
 232                 clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);
 233
 234         clocksource_register(&clocksource_sh);
 235 }
 236
 237 #ifdef CONFIG_GENERIC_TIME
 238 unsigned long long sched_clock(void)
 239 {
 240         unsigned long long ticks = clocksource_sh.read();
 241         return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
 242 }
 243 #endif
 244
 245 void __init time_init(void)
 246 {
 247         if (board_time_init)
 248                 board_time_init();
 249
 250         clk_init();
 251
 252         rtc_sh_get_time(&xtime);
 253         set_normalized_timespec(&wall_to_monotonic,
 254                                 -xtime.tv_sec, -xtime.tv_nsec);
 255
 256         /*
 257          * Find the timer to use as the system timer, it will be
 258          * initialized for us.
 259          */
 260         sys_timer = get_sys_timer();
 261         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
 262
 263         if (sys_timer->ops->read)
 264                 clocksource_sh.read = sys_timer->ops->read;
 265
 266         init_sh_clocksource();
 267
 268         if (sh_hpt_frequency)
 269                 printk("Using %lu.%03lu MHz high precision timer.\n",
 270                        ((sh_hpt_frequency + 500) / 1000) / 1000,
 271                        ((sh_hpt_frequency + 500) / 1000) % 1000);
 272
 273 #if defined(CONFIG_SH_KGDB)
 274         /*
 275          * Set up kgdb as requested. We do it here because the serial
 276          * init uses the timer vars we just set up for figuring baud.
 277          */
 278         kgdb_init();
 279 #endif
 280 }