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); 38 update_process_times(user_mode(get_irq_regs())); 39 profile_tick(CPU_PROFILING); 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 67 void read_persistent_clock(struct timespec *ts) 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 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET 84 85 static int __init rtc_init(void) 86 { 87 struct platform_device *pdev; 88 89 if (!mach_hwclk) 90 return -ENODEV; 91 92 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 93 return PTR_ERR_OR_ZERO(pdev); 94 } 95 96 module_init(rtc_init); 97 98 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */ 99 100 void __init time_init(void) 101 { 102 mach_sched_init(timer_interrupt); 103 } 104