Linux Kernel  3.7.1
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time.c
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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 ([email protected])
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 "xtime_update()" routine every clocktick
54  */
56 {
58 
59  xtime_update(1);
60 
61 #ifdef CONFIG_HEARTBEAT
62  static unsigned short n;
63  n++;
64  __set_LEDS(n);
65 #endif /* CONFIG_HEARTBEAT */
66 
68 
69  return IRQ_HANDLED;
70 }
71 
73 {
74  unsigned short base, pre, prediv;
75 
76  /* set the scheduling timer going */
77  pre = 1;
78  prediv = 4;
79  base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
80 
81  __set_TPRV(pre);
82  __set_TxCKSL_DATA(0, prediv);
84  __set_TCSR_DATA(0, base & 0xff);
85  __set_TCSR_DATA(0, base >> 8);
86 }
87 
88 
90 {
91  unsigned int year, mon, day, hour, min, sec;
92 
93  extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
94 
95  /* FIX by dqg : Set to zero for platforms that don't have tod */
96  /* without this time is undefined and can overflow time_t, causing */
97  /* very strange errors */
98  year = 1980;
99  mon = day = 1;
100  hour = min = sec = 0;
101  arch_gettod (&year, &mon, &day, &hour, &min, &sec);
102 
103  if ((year += 1900) < 1970)
104  year += 100;
105  ts->tv_sec = mktime(year, mon, day, hour, min, sec);
106  ts->tv_nsec = 0;
107 }
108 
109 void time_init(void)
110 {
111  /* install scheduling interrupt handler */
112  setup_irq(IRQ_CPU_TIMER0, &timer_irq);
113 
115 }
116 
117 /*
118  * Scheduler clock - returns current time in nanosec units.
119  */
120 unsigned long long sched_clock(void)
121 {
122  return jiffies_64 * (1000000000 / HZ);
123 }