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/export.h> 15 #include <linux/module.h> 16 #include <linux/sched.h> 17 #include <linux/kernel.h> 18 #include <linux/param.h> 19 #include <linux/string.h> 20 #include <linux/mm.h> 21 #include <linux/rtc.h> 22 #include <linux/platform_device.h> 23 24 #include <asm/machdep.h> 25 #include <asm/io.h> 26 #include <asm/irq_regs.h> 27 28 #include <linux/time.h> 29 #include <linux/timex.h> 30 #include <linux/profile.h> 31 32 33 unsigned long (*mach_random_get_entropy)(void); 34 EXPORT_SYMBOL_GPL(mach_random_get_entropy); 35 36 37 /* 38 * timer_interrupt() needs to keep up the real-time clock, 39 * as well as call the "xtime_update()" routine every clocktick 40 */ 41 static irqreturn_t timer_interrupt(int irq, void *dummy) 42 { 43 xtime_update(1); 44 update_process_times(user_mode(get_irq_regs())); 45 profile_tick(CPU_PROFILING); 46 47 #ifdef CONFIG_HEARTBEAT 48 /* use power LED as a heartbeat instead -- much more useful 49 for debugging -- based on the version for PReP by Cort */ 50 /* acts like an actual heart beat -- ie thump-thump-pause... */ 51 if (mach_heartbeat) { 52 static unsigned cnt = 0, period = 0, dist = 0; 53 54 if (cnt == 0 || cnt == dist) 55 mach_heartbeat( 1 ); 56 else if (cnt == 7 || cnt == dist+7) 57 mach_heartbeat( 0 ); 58 59 if (++cnt > period) { 60 cnt = 0; 61 /* The hyperbolic function below modifies the heartbeat period 62 * length in dependency of the current (5min) load. It goes 63 * through the points f(0)=126, f(1)=86, f(5)=51, 64 * f(inf)->30. */ 65 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30; 66 dist = period / 4; 67 } 68 } 69 #endif /* CONFIG_HEARTBEAT */ 70 return IRQ_HANDLED; 71 } 72 73 void read_persistent_clock(struct timespec *ts) 74 { 75 struct rtc_time time; 76 ts->tv_sec = 0; 77 ts->tv_nsec = 0; 78 79 if (mach_hwclk) { 80 mach_hwclk(0, &time); 81 82 if ((time.tm_year += 1900) < 1970) 83 time.tm_year += 100; 84 ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday, 85 time.tm_hour, time.tm_min, time.tm_sec); 86 } 87 } 88 89 #if defined(CONFIG_ARCH_USES_GETTIMEOFFSET) && IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 90 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 91 { 92 mach_hwclk(0, tm); 93 return rtc_valid_tm(tm); 94 } 95 96 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 97 { 98 if (mach_hwclk(1, tm) < 0) 99 return -EOPNOTSUPP; 100 return 0; 101 } 102 103 static int rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 104 { 105 struct rtc_pll_info pll; 106 struct rtc_pll_info __user *argp = (void __user *)arg; 107 108 switch (cmd) { 109 case RTC_PLL_GET: 110 if (!mach_get_rtc_pll || mach_get_rtc_pll(&pll)) 111 return -EINVAL; 112 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0; 113 114 case RTC_PLL_SET: 115 if (!mach_set_rtc_pll) 116 return -EINVAL; 117 if (!capable(CAP_SYS_TIME)) 118 return -EACCES; 119 if (copy_from_user(&pll, argp, sizeof(pll))) 120 return -EFAULT; 121 return mach_set_rtc_pll(&pll); 122 } 123 124 return -ENOIOCTLCMD; 125 } 126 127 static const struct rtc_class_ops generic_rtc_ops = { 128 .ioctl = rtc_ioctl, 129 .read_time = rtc_generic_get_time, 130 .set_time = rtc_generic_set_time, 131 }; 132 133 static int __init rtc_init(void) 134 { 135 struct platform_device *pdev; 136 137 if (!mach_hwclk) 138 return -ENODEV; 139 140 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 141 &generic_rtc_ops, 142 sizeof(generic_rtc_ops)); 143 return PTR_ERR_OR_ZERO(pdev); 144 } 145 146 module_init(rtc_init); 147 148 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */ 149 150 void __init time_init(void) 151 { 152 mach_sched_init(timer_interrupt); 153 } 154