Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
time.c
Go to the documentation of this file.
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 /*
32  * timer_interrupt() needs to keep up the real-time clock,
33  * as well as call the "xtime_update()" routine every clocktick
34  */
35 static irqreturn_t timer_interrupt(int irq, void *dummy)
36 {
37  xtime_update(1);
40 
41 #ifdef CONFIG_HEARTBEAT
42  /* use power LED as a heartbeat instead -- much more useful
43  for debugging -- based on the version for PReP by Cort */
44  /* acts like an actual heart beat -- ie thump-thump-pause... */
45  if (mach_heartbeat) {
46  static unsigned cnt = 0, period = 0, dist = 0;
47 
48  if (cnt == 0 || cnt == dist)
49  mach_heartbeat( 1 );
50  else if (cnt == 7 || cnt == dist+7)
51  mach_heartbeat( 0 );
52 
53  if (++cnt > period) {
54  cnt = 0;
55  /* The hyperbolic function below modifies the heartbeat period
56  * length in dependency of the current (5min) load. It goes
57  * through the points f(0)=126, f(1)=86, f(5)=51,
58  * f(inf)->30. */
59  period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
60  dist = period / 4;
61  }
62  }
63 #endif /* CONFIG_HEARTBEAT */
64  return IRQ_HANDLED;
65 }
66 
68 {
69  struct rtc_time time;
70  ts->tv_sec = 0;
71  ts->tv_nsec = 0;
72 
73  if (mach_hwclk) {
74  mach_hwclk(0, &time);
75 
76  if ((time.tm_year += 1900) < 1970)
77  time.tm_year += 100;
78  ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
79  time.tm_hour, time.tm_min, time.tm_sec);
80  }
81 }
82 
83 void __init time_init(void)
84 {
86 }
87 
88 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
89 
91 {
92  return mach_gettimeoffset() * 1000;
93 }
94 
95 static int __init rtc_init(void)
96 {
97  struct platform_device *pdev;
98 
99  if (!mach_hwclk)
100  return -ENODEV;
101 
102  pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
103  return PTR_RET(pdev);
104 }
105 
106 module_init(rtc_init);
107 
108 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */