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 }
123
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