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/sched/loadavg.h> 18 #include <linux/kernel.h> 19 #include <linux/param.h> 20 #include <linux/string.h> 21 #include <linux/mm.h> 22 #include <linux/rtc.h> 23 #include <linux/platform_device.h> 24 25 #include <asm/machdep.h> 26 #include <asm/io.h> 27 #include <asm/irq_regs.h> 28 29 #include <linux/time.h> 30 #include <linux/timex.h> 31 #include <linux/profile.h> 32 33 34 unsigned long (*mach_random_get_entropy)(void); 35 EXPORT_SYMBOL_GPL(mach_random_get_entropy); 36 37 38 /* 39 * timer_interrupt() needs to keep up the real-time clock, 40 * as well as call the "xtime_update()" routine every clocktick 41 */ 42 static irqreturn_t timer_interrupt(int irq, void *dummy) 43 { 44 xtime_update(1); 45 update_process_times(user_mode(get_irq_regs())); 46 profile_tick(CPU_PROFILING); 47 48 #ifdef CONFIG_HEARTBEAT 49 /* use power LED as a heartbeat instead -- much more useful 50 for debugging -- based on the version for PReP by Cort */ 51 /* acts like an actual heart beat -- ie thump-thump-pause... */ 52 if (mach_heartbeat) { 53 static unsigned cnt = 0, period = 0, dist = 0; 54 55 if (cnt == 0 || cnt == dist) 56 mach_heartbeat( 1 ); 57 else if (cnt == 7 || cnt == dist+7) 58 mach_heartbeat( 0 ); 59 60 if (++cnt > period) { 61 cnt = 0; 62 /* The hyperbolic function below modifies the heartbeat period 63 * length in dependency of the current (5min) load. It goes 64 * through the points f(0)=126, f(1)=86, f(5)=51, 65 * f(inf)->30. */ 66 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30; 67 dist = period / 4; 68 } 69 } 70 #endif /* CONFIG_HEARTBEAT */ 71 return IRQ_HANDLED; 72 } 73 74 void read_persistent_clock(struct timespec *ts) 75 { 76 struct rtc_time time; 77 ts->tv_sec = 0; 78 ts->tv_nsec = 0; 79 80 if (mach_hwclk) { 81 mach_hwclk(0, &time); 82 83 if ((time.tm_year += 1900) < 1970) 84 time.tm_year += 100; 85 ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday, 86 time.tm_hour, time.tm_min, time.tm_sec); 87 } 88 } 89 90 #if defined(CONFIG_ARCH_USES_GETTIMEOFFSET) && IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 91 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 92 { 93 mach_hwclk(0, tm); 94 return rtc_valid_tm(tm); 95 } 96 97 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 98 { 99 if (mach_hwclk(1, tm) < 0) 100 return -EOPNOTSUPP; 101 return 0; 102 } 103 104 static int rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 105 { 106 struct rtc_pll_info pll; 107 struct rtc_pll_info __user *argp = (void __user *)arg; 108 109 switch (cmd) { 110 case RTC_PLL_GET: 111 if (!mach_get_rtc_pll || mach_get_rtc_pll(&pll)) 112 return -EINVAL; 113 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0; 114 115 case RTC_PLL_SET: 116 if (!mach_set_rtc_pll) 117 return -EINVAL; 118 if (!capable(CAP_SYS_TIME)) 119 return -EACCES; 120 if (copy_from_user(&pll, argp, sizeof(pll))) 121 return -EFAULT; 122 return mach_set_rtc_pll(&pll); 123 } 124 125 return -ENOIOCTLCMD; 126 } 127 128 static const struct rtc_class_ops generic_rtc_ops = { 129 .ioctl = rtc_ioctl, 130 .read_time = rtc_generic_get_time, 131 .set_time = rtc_generic_set_time, 132 }; 133 134 static int __init rtc_init(void) 135 { 136 struct platform_device *pdev; 137 138 if (!mach_hwclk) 139 return -ENODEV; 140 141 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 142 &generic_rtc_ops, 143 sizeof(generic_rtc_ops)); 144 return PTR_ERR_OR_ZERO(pdev); 145 } 146 147 module_init(rtc_init); 148 149 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */ 150 151 void __init time_init(void) 152 { 153 mach_sched_init(timer_interrupt); 154 } 155