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 u64 jiffies_64 = INITIAL_JIFFIES;
  38 EXPORT_SYMBOL(jiffies_64);
  39
  40 unsigned long __nongprelbss __clkin_clock_speed_HZ;
  41 unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
  42 unsigned long __nongprelbss __res_bus_clock_speed_HZ;
  43 unsigned long __nongprelbss __sdram_clock_speed_HZ;
  44 unsigned long __nongprelbss __core_bus_clock_speed_HZ;
  45 unsigned long __nongprelbss __core_clock_speed_HZ;
  46 unsigned long __nongprelbss __dsu_clock_speed_HZ;
  47 unsigned long __nongprelbss __serial_clock_speed_HZ;
  48 unsigned long __delay_loops_MHz;
  49
  50 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
  51
  52 static struct irqaction timer_irq  = {
  53         timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE, "timer", NULL, NULL
  54 };
  55
  56 static inline int set_rtc_mmss(unsigned long nowtime)
  57 {
  58         return -1;
  59 }
  60
  61 /*
  62  * timer_interrupt() needs to keep up the real-time clock,
  63  * as well as call the "do_timer()" routine every clocktick
  64  */
  65 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
  66 {
  67         /* last time the cmos clock got updated */
  68         static long last_rtc_update = 0;
  69
  70         /*
  71          * Here we are in the timer irq handler. We just have irqs locally
  72          * disabled but we don't know if the timer_bh is running on the other
  73          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
  74          * the irq version of write_lock because as just said we have irq
  75          * locally disabled. -arca
  76          */
  77         write_seqlock(&xtime_lock);
  78
  79         do_timer(regs);
  80         update_process_times(user_mode(regs));
  81         profile_tick(CPU_PROFILING, regs);
  82
  83         /*
  84          * If we have an externally synchronized Linux clock, then update
  85          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  86          * called as close as possible to 500 ms before the new second starts.
  87          */
  88         if ((time_status & STA_UNSYNC) == 0 &&
  89             xtime.tv_sec > last_rtc_update + 660 &&
  90             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  91             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
  92             ) {
  93                 if (set_rtc_mmss(xtime.tv_sec) == 0)
  94                         last_rtc_update = xtime.tv_sec;
  95                 else
  96                         last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
  97         }
  98
  99 #ifdef CONFIG_HEARTBEAT
 100         static unsigned short n;
 101         n++;
 102         __set_LEDS(n);
 103 #endif /* CONFIG_HEARTBEAT */
 104
 105         write_sequnlock(&xtime_lock);
 106         return IRQ_HANDLED;
 107 }
 108
 109 void time_divisor_init(void)
 110 {
 111         unsigned short base, pre, prediv;
 112
 113         /* set the scheduling timer going */
 114         pre = 1;
 115         prediv = 4;
 116         base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
 117
 118         __set_TPRV(pre);
 119         __set_TxCKSL_DATA(0, prediv);
 120         __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
 121         __set_TCSR_DATA(0, base & 0xff);
 122         __set_TCSR_DATA(0, base >> 8);
 123 }
 124
 125 void time_init(void)
 126 {
 127         unsigned int year, mon, day, hour, min, sec;
 128
 129         extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
 130
 131         /* FIX by dqg : Set to zero for platforms that don't have tod */
 132         /* without this time is undefined and can overflow time_t, causing  */
 133         /* very stange errors */
 134         year = 1980;
 135         mon = day = 1;
 136         hour = min = sec = 0;
 137         arch_gettod (&year, &mon, &day, &hour, &min, &sec);
 138
 139         if ((year += 1900) < 1970)
 140                 year += 100;
 141         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 142         xtime.tv_nsec = 0;
 143
 144         /* install scheduling interrupt handler */
 145         setup_irq(IRQ_CPU_TIMER0, &timer_irq);
 146
 147         time_divisor_init();
 148 }
 149
 150 /*
 151  * This version of gettimeofday has near microsecond resolution.
 152  */
 153 void do_gettimeofday(struct timeval *tv)
 154 {
 155         unsigned long seq;
 156         unsigned long usec, sec;
 157         unsigned long max_ntp_tick;
 158
 159         do {
 160                 unsigned long lost;
 161
 162                 seq = read_seqbegin(&xtime_lock);
 163
 164                 usec = 0;
 165                 lost = jiffies - wall_jiffies;
 166
 167                 /*
 168                  * If time_adjust is negative then NTP is slowing the clock
 169                  * so make sure not to go into next possible interval.
 170                  * Better to lose some accuracy than have time go backwards..
 171                  */
 172                 if (unlikely(time_adjust < 0)) {
 173                         max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
 174                         usec = min(usec, max_ntp_tick);
 175
 176                         if (lost)
 177                                 usec += lost * max_ntp_tick;
 178                 }
 179                 else if (unlikely(lost))
 180                         usec += lost * (USEC_PER_SEC / HZ);
 181
 182                 sec = xtime.tv_sec;
 183                 usec += (xtime.tv_nsec / 1000);
 184         } while (read_seqretry(&xtime_lock, seq));
 185
 186         while (usec >= 1000000) {
 187                 usec -= 1000000;
 188                 sec++;
 189         }
 190
 191         tv->tv_sec = sec;
 192         tv->tv_usec = usec;
 193 }
 194
 195 int do_settimeofday(struct timespec *tv)
 196 {
 197         time_t wtm_sec, sec = tv->tv_sec;
 198         long wtm_nsec, nsec = tv->tv_nsec;
 199
 200         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 201                 return -EINVAL;
 202
 203         write_seqlock_irq(&xtime_lock);
 204         /*
 205          * This is revolting. We need to set "xtime" correctly. However, the
 206          * value in this location is the value at the most recent update of
 207          * wall time.  Discover what correction gettimeofday() would have
 208          * made, and then undo it!
 209          */
 210         nsec -= 0 * NSEC_PER_USEC;
 211         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 212
 213         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 214         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 215
 216         set_normalized_timespec(&xtime, sec, nsec);
 217         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 218
 219         time_adjust = 0;                /* stop active adjtime() */
 220         time_status |= STA_UNSYNC;
 221         time_maxerror = NTP_PHASE_LIMIT;
 222         time_esterror = NTP_PHASE_LIMIT;
 223         write_sequnlock_irq(&xtime_lock);
 224         clock_was_set();
 225         return 0;
 226 }
 227
 228 /*
 229  * Scheduler clock - returns current time in nanosec units.
 230  */
 231 unsigned long long sched_clock(void)
 232 {
 233         return jiffies_64 * (1000000000 / HZ);
 234 }