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
  33 unsigned long __nongprelbss __clkin_clock_speed_HZ;
  34 unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
  35 unsigned long __nongprelbss __res_bus_clock_speed_HZ;
  36 unsigned long __nongprelbss __sdram_clock_speed_HZ;
  37 unsigned long __nongprelbss __core_bus_clock_speed_HZ;
  38 unsigned long __nongprelbss __core_clock_speed_HZ;
  39 unsigned long __nongprelbss __dsu_clock_speed_HZ;
  40 unsigned long __nongprelbss __serial_clock_speed_HZ;
  41 unsigned long __delay_loops_MHz;
  42
  43 static irqreturn_t timer_interrupt(int irq, void *dummy);
  44
  45 static 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  */
  54 static 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
  71 void 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
  88 void 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
 108 void 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  */
 119 unsigned long long sched_clock(void)
 120 {
 121         return jiffies_64 * (1000000000 / HZ);
 122 }