release/src-rt-6.x.4708/linux/linux-2.6.36/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         .flags = IRQF_DISABLED,
  48         .name = "timer",
  49 };
  50
  51 /*
  52  * timer_interrupt() needs to keep up the real-time clock,
  53  * as well as call the "do_timer()" routine every clocktick
  54  */
  55 static irqreturn_t timer_interrupt(int irq, void *dummy)
  56 {
  57         profile_tick(CPU_PROFILING);
  58         /*
  59          * Here we are in the timer irq handler. We just have irqs locally
  60          * disabled but we don't know if the timer_bh is running on the other
  61          * CPU. We need to avoid to SMP race with it. NOTE: we don't need
  62          * the irq version of write_lock because as just said we have irq
  63          * locally disabled. -arca
  64          */
  65         write_seqlock(&xtime_lock);
  66
  67         do_timer(1);
  68
  69 #ifdef CONFIG_HEARTBEAT
  70         static unsigned short n;
  71         n++;
  72         __set_LEDS(n);
  73 #endif /* CONFIG_HEARTBEAT */
  74
  75         write_sequnlock(&xtime_lock);
  76
  77         update_process_times(user_mode(get_irq_regs()));
  78
  79         return IRQ_HANDLED;
  80 }
  81
  82 void time_divisor_init(void)
  83 {
  84         unsigned short base, pre, prediv;
  85
  86         /* set the scheduling timer going */
  87         pre = 1;
  88         prediv = 4;
  89         base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
  90
  91         __set_TPRV(pre);
  92         __set_TxCKSL_DATA(0, prediv);
  93         __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
  94         __set_TCSR_DATA(0, base & 0xff);
  95         __set_TCSR_DATA(0, base >> 8);
  96 }
  97
  98
  99 void read_persistent_clock(struct timespec *ts)
 100 {
 101         unsigned int year, mon, day, hour, min, sec;
 102
 103         extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
 104
 105         /* FIX by dqg : Set to zero for platforms that don't have tod */
 106         /* without this time is undefined and can overflow time_t, causing  */
 107         /* very strange errors */
 108         year = 1980;
 109         mon = day = 1;
 110         hour = min = sec = 0;
 111         arch_gettod (&year, &mon, &day, &hour, &min, &sec);
 112
 113         if ((year += 1900) < 1970)
 114                 year += 100;
 115         ts->tv_sec = mktime(year, mon, day, hour, min, sec);
 116         ts->tv_nsec = 0;
 117 }
 118
 119 void time_init(void)
 120 {
 121         /* install scheduling interrupt handler */
 122         setup_irq(IRQ_CPU_TIMER0, &timer_irq);
 123
 124         time_divisor_init();
 125 }
 126
 127 /*
 128  * Scheduler clock - returns current time in nanosec units.
 129  */
 130 unsigned long long sched_clock(void)
 131 {
 132         return jiffies_64 * (1000000000 / HZ);
 133 }