LXR linux/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/module.h>
  14#include <linux/errno.h>
  15#include <linux/sched.h>
  16#include <linux/kernel.h>
  17#include <linux/param.h>
  18#include <linux/string.h>
  19#include <linux/interrupt.h>
  20#include <linux/profile.h>
  21#include <linux/irq.h>
  22#include <linux/mm.h>
  23
  24#include <asm/io.h>
  25#include <asm/timer-regs.h>
  26#include <asm/mb-regs.h>
  27#include <asm/mb86943a.h>
  28
  29#include <linux/timex.h>
  30
  31#define TICK_SIZE (tick_nsec / 1000)
  32
  33unsigned long __nongprelbss __clkin_clock_speed_HZ;
  34unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
  35unsigned long __nongprelbss __res_bus_clock_speed_HZ;
  36unsigned long __nongprelbss __sdram_clock_speed_HZ;
  37unsigned long __nongprelbss __core_bus_clock_speed_HZ;
  38unsigned long __nongprelbss __core_clock_speed_HZ;
  39unsigned long __nongprelbss __dsu_clock_speed_HZ;
  40unsigned long __nongprelbss __serial_clock_speed_HZ;
  41unsigned long __delay_loops_MHz;
  42
  43static irqreturn_t timer_interrupt(int irq, void *dummy);
  44
  45static struct irqaction timer_irq  = {
  46        .handler = timer_interrupt,
  47        .name = "timer",
  48};
  49
  50/*
  51 * timer_interrupt() needs to keep up the real-time clock,
  52 * as well as call the "xtime_update()" routine every clocktick
  53 */
  54static irqreturn_t timer_interrupt(int irq, void *dummy)
  55{
  56        profile_tick(CPU_PROFILING);
  57
  58        xtime_update(1);
  59
  60#ifdef CONFIG_HEARTBEAT
  61        static unsigned short n;
  62        n++;
  63        __set_LEDS(n);
  64#endif /* CONFIG_HEARTBEAT */
  65
  66        update_process_times(user_mode(get_irq_regs()));
  67
  68        return IRQ_HANDLED;
  69}
  70
  71void time_divisor_init(void)
  72{
  73        unsigned short base, pre, prediv;
  74
  75        /* set the scheduling timer going */
  76        pre = 1;
  77        prediv = 4;
  78        base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
  79
  80        __set_TPRV(pre);
  81        __set_TxCKSL_DATA(0, prediv);
  82        __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
  83        __set_TCSR_DATA(0, base & 0xff);
  84        __set_TCSR_DATA(0, base >> 8);
  85}
  86
  87
  88void read_persistent_clock(struct timespec *ts)
  89{
  90        unsigned int year, mon, day, hour, min, sec;
  91
  92        extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
  93
  94        /* FIX by dqg : Set to zero for platforms that don't have tod */
  95        /* without this time is undefined and can overflow time_t, causing  */
  96        /* very strange errors */
  97        year = 1980;
  98        mon = day = 1;
  99        hour = min = sec = 0;
 100        arch_gettod (&year, &mon, &day, &hour, &min, &sec);
 101
 102        if ((year += 1900) < 1970)
 103                year += 100;
 104        ts->tv_sec = mktime(year, mon, day, hour, min, sec);
 105        ts->tv_nsec = 0;
 106}
 107
 108void time_init(void)
 109{
 110        /* install scheduling interrupt handler */
 111        setup_irq(IRQ_CPU_TIMER0, &timer_irq);
 112
 113        time_divisor_init();
 114}
 115
 116/*
 117 * Scheduler clock - returns current time in nanosec units.
 118 */
 119unsigned long long sched_clock(void)
 120{
 121        return jiffies_64 * (1000000000 / HZ);
 122}
 123