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1/*
2 * linux/arch/m68k/kernel/time.c
3 *
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 *
6 * This file contains the m68k-specific time handling details.
7 * Most of the stuff is located in the machine specific files.
8 *
9 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
10 * "A Kernel Model for Precision Timekeeping" by Dave Mills
11 */
12
13#include <linux/errno.h>
14#include <linux/module.h>
15#include <linux/sched.h>
16#include <linux/kernel.h>
17#include <linux/param.h>
18#include <linux/string.h>
19#include <linux/mm.h>
20#include <linux/rtc.h>
21#include <linux/platform_device.h>
22
23#include <asm/machdep.h>
24#include <asm/io.h>
25#include <asm/irq_regs.h>
26
27#include <linux/time.h>
28#include <linux/timex.h>
29#include <linux/profile.h>
30
31
32unsigned long (*mach_random_get_entropy)(void);
33
34
35/*
36 * timer_interrupt() needs to keep up the real-time clock,
37 * as well as call the "xtime_update()" routine every clocktick
38 */
39static irqreturn_t timer_interrupt(int irq, void *dummy)
40{
41 xtime_update(1);
42 update_process_times(user_mode(get_irq_regs()));
43 profile_tick(CPU_PROFILING);
44
45#ifdef CONFIG_HEARTBEAT
46 /* use power LED as a heartbeat instead -- much more useful
47 for debugging -- based on the version for PReP by Cort */
48 /* acts like an actual heart beat -- ie thump-thump-pause... */
49 if (mach_heartbeat) {
50 static unsigned cnt = 0, period = 0, dist = 0;
51
52 if (cnt == 0 || cnt == dist)
53 mach_heartbeat( 1 );
54 else if (cnt == 7 || cnt == dist+7)
55 mach_heartbeat( 0 );
56
57 if (++cnt > period) {
58 cnt = 0;
59 /* The hyperbolic function below modifies the heartbeat period
60 * length in dependency of the current (5min) load. It goes
61 * through the points f(0)=126, f(1)=86, f(5)=51,
62 * f(inf)->30. */
63 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
64 dist = period / 4;
65 }
66 }
67#endif /* CONFIG_HEARTBEAT */
68 return IRQ_HANDLED;
69}
70
71void read_persistent_clock(struct timespec *ts)
72{
73 struct rtc_time time;
74 ts->tv_sec = 0;
75 ts->tv_nsec = 0;
76
77 if (mach_hwclk) {
78 mach_hwclk(0, &time);
79
80 if ((time.tm_year += 1900) < 1970)
81 time.tm_year += 100;
82 ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
83 time.tm_hour, time.tm_min, time.tm_sec);
84 }
85}
86
87#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
88
89static int __init rtc_init(void)
90{
91 struct platform_device *pdev;
92
93 if (!mach_hwclk)
94 return -ENODEV;
95
96 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
97 return PTR_ERR_OR_ZERO(pdev);
98}
99
100module_init(rtc_init);
101
102#endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
103
104void __init time_init(void)
105{
106 mach_sched_init(timer_interrupt);
107}