arch/frv/kernel/time.c

   1 /* time.c: FRV arch-specific time handling
   2  *
   3  * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  * - Derived from arch/m68k/kernel/time.c
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/config.h> /* CONFIG_HEARTBEAT */
  14 #include <linux/module.h>
  15 #include <linux/errno.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/param.h>
  19 #include <linux/string.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/profile.h>
  22 #include <linux/irq.h>
  23 #include <linux/mm.h>
  24
  25 #include <asm/io.h>
  26 #include <asm/timer-regs.h>
  27 #include <asm/mb-regs.h>
  28 #include <asm/mb86943a.h>
  29 #include <asm/irq-routing.h>
  30
  31 #include <linux/timex.h>
  32
  33 #define TICK_SIZE (tick_nsec / 1000)
  34
  35 extern unsigned long wall_jiffies;
  36
  37 unsigned long __nongprelbss __clkin_clock_speed_HZ;
  38 unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
  39 unsigned long __nongprelbss __res_bus_clock_speed_HZ;
  40 unsigned long __nongprelbss __sdram_clock_speed_HZ;
  41 unsigned long __nongprelbss __core_bus_clock_speed_HZ;
  42 unsigned long __nongprelbss __core_clock_speed_HZ;
  43 unsigned long __nongprelbss __dsu_clock_speed_HZ;
  44 unsigned long __nongprelbss __serial_clock_speed_HZ;
  45 unsigned long __delay_loops_MHz;
  46
  47 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
  48
  49 static struct irqaction timer_irq  = {
  50         timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE, "timer", NULL, NULL
  51 };
  52
  53 static inline int set_rtc_mmss(unsigned long nowtime)
  54 {
  55         return -1;
  56 }
  57
  58 /*
  59  * timer_interrupt() needs to keep up the real-time clock,
  60  * as well as call the "do_timer()" routine every clocktick
  61  */
  62 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
  63 {
  64         /* last time the cmos clock got updated */
  65         static long last_rtc_update = 0;
  66
  67         /*
  68          * Here we are in the timer irq handler. We just have irqs locally
  69          * disabled but we don't know if the timer_bh is running on the other
  70          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
  71          * the irq version of write_lock because as just said we have irq
  72          * locally disabled. -arca
  73          */
  74         write_seqlock(&xtime_lock);
  75
  76         do_timer(regs);
  77         update_process_times(user_mode(regs));
  78         profile_tick(CPU_PROFILING, regs);
  79
  80         /*
  81          * If we have an externally synchronized Linux clock, then update
  82          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  83          * called as close as possible to 500 ms before the new second starts.
  84          */
  85         if (ntp_synced() &&
  86             xtime.tv_sec > last_rtc_update + 660 &&
  87             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  88             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
  89             ) {
  90                 if (set_rtc_mmss(xtime.tv_sec) == 0)
  91                         last_rtc_update = xtime.tv_sec;
  92                 else
  93                         last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
  94         }
  95
  96 #ifdef CONFIG_HEARTBEAT
  97         static unsigned short n;
  98         n++;
  99         __set_LEDS(n);
 100 #endif /* CONFIG_HEARTBEAT */
 101
 102         write_sequnlock(&xtime_lock);
 103         return IRQ_HANDLED;
 104 }
 105
 106 void time_divisor_init(void)
 107 {
 108         unsigned short base, pre, prediv;
 109
 110         /* set the scheduling timer going */
 111         pre = 1;
 112         prediv = 4;
 113         base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
 114
 115         __set_TPRV(pre);
 116         __set_TxCKSL_DATA(0, prediv);
 117         __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
 118         __set_TCSR_DATA(0, base & 0xff);
 119         __set_TCSR_DATA(0, base >> 8);
 120 }
 121
 122 void time_init(void)
 123 {
 124         unsigned int year, mon, day, hour, min, sec;
 125
 126         extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
 127
 128         /* FIX by dqg : Set to zero for platforms that don't have tod */
 129         /* without this time is undefined and can overflow time_t, causing  */
 130         /* very stange errors */
 131         year = 1980;
 132         mon = day = 1;
 133         hour = min = sec = 0;
 134         arch_gettod (&year, &mon, &day, &hour, &min, &sec);
 135
 136         if ((year += 1900) < 1970)
 137                 year += 100;
 138         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 139         xtime.tv_nsec = 0;
 140
 141         /* install scheduling interrupt handler */
 142         setup_irq(IRQ_CPU_TIMER0, &timer_irq);
 143
 144         time_divisor_init();
 145 }
 146
 147 /*
 148  * This version of gettimeofday has near microsecond resolution.
 149  */
 150 void do_gettimeofday(struct timeval *tv)
 151 {
 152         unsigned long seq;
 153         unsigned long usec, sec;
 154         unsigned long max_ntp_tick;
 155
 156         do {
 157                 unsigned long lost;
 158
 159                 seq = read_seqbegin(&xtime_lock);
 160
 161                 usec = 0;
 162                 lost = jiffies - wall_jiffies;
 163
 164                 /*
 165                  * If time_adjust is negative then NTP is slowing the clock
 166                  * so make sure not to go into next possible interval.
 167                  * Better to lose some accuracy than have time go backwards..
 168                  */
 169                 if (unlikely(time_adjust < 0)) {
 170                         max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
 171                         usec = min(usec, max_ntp_tick);
 172
 173                         if (lost)
 174                                 usec += lost * max_ntp_tick;
 175                 }
 176                 else if (unlikely(lost))
 177                         usec += lost * (USEC_PER_SEC / HZ);
 178
 179                 sec = xtime.tv_sec;
 180                 usec += (xtime.tv_nsec / 1000);
 181         } while (read_seqretry(&xtime_lock, seq));
 182
 183         while (usec >= 1000000) {
 184                 usec -= 1000000;
 185                 sec++;
 186         }
 187
 188         tv->tv_sec = sec;
 189         tv->tv_usec = usec;
 190 }
 191
 192 EXPORT_SYMBOL(do_gettimeofday);
 193
 194 int do_settimeofday(struct timespec *tv)
 195 {
 196         time_t wtm_sec, sec = tv->tv_sec;
 197         long wtm_nsec, nsec = tv->tv_nsec;
 198
 199         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 200                 return -EINVAL;
 201
 202         write_seqlock_irq(&xtime_lock);
 203         /*
 204          * This is revolting. We need to set "xtime" correctly. However, the
 205          * value in this location is the value at the most recent update of
 206          * wall time.  Discover what correction gettimeofday() would have
 207          * made, and then undo it!
 208          */
 209         nsec -= 0 * NSEC_PER_USEC;
 210         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 211
 212         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 213         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 214
 215         set_normalized_timespec(&xtime, sec, nsec);
 216         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 217
 218         ntp_clear();
 219         write_sequnlock_irq(&xtime_lock);
 220         clock_was_set();
 221         return 0;
 222 }
 223
 224 EXPORT_SYMBOL(do_settimeofday);
 225
 226 /*
 227  * Scheduler clock - returns current time in nanosec units.
 228  */
 229 unsigned long long sched_clock(void)
 230 {
 231         return jiffies_64 * (1000000000 / HZ);
 232 }