arch/m68k/kernel/time.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/m68k/kernel/time.c
   4  *
   5  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   6  *
   7  * This file contains the m68k-specific time handling details.
   8  * Most of the stuff is located in the machine specific files.
   9  *
  10  * 1997-09-10   Updated NTP code according to technical memorandum Jan '96
  11  *              "A Kernel Model for Precision Timekeeping" by Dave Mills
  12  */
  13
  14 #include <linux/errno.h>
  15 #include <linux/export.h>
  16 #include <linux/module.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/loadavg.h>
  19 #include <linux/kernel.h>
  20 #include <linux/param.h>
  21 #include <linux/string.h>
  22 #include <linux/mm.h>
  23 #include <linux/rtc.h>
  24 #include <linux/platform_device.h>
  25
  26 #include <asm/machdep.h>
  27 #include <asm/io.h>
  28 #include <asm/irq_regs.h>
  29
  30 #include <linux/time.h>
  31 #include <linux/timex.h>
  32 #include <linux/profile.h>
  33
  34
  35 unsigned long (*mach_random_get_entropy)(void);
  36 EXPORT_SYMBOL_GPL(mach_random_get_entropy);
  37
  38
  39 /*
  40  * timer_interrupt() needs to keep up the real-time clock,
  41  * as well as call the "xtime_update()" routine every clocktick
  42  */
  43 static irqreturn_t timer_interrupt(int irq, void *dummy)
  44 {
  45         xtime_update(1);
  46         update_process_times(user_mode(get_irq_regs()));
  47         profile_tick(CPU_PROFILING);
  48
  49 #ifdef CONFIG_HEARTBEAT
  50         /* use power LED as a heartbeat instead -- much more useful
  51            for debugging -- based on the version for PReP by Cort */
  52         /* acts like an actual heart beat -- ie thump-thump-pause... */
  53         if (mach_heartbeat) {
  54             static unsigned cnt = 0, period = 0, dist = 0;
  55
  56             if (cnt == 0 || cnt == dist)
  57                 mach_heartbeat( 1 );
  58             else if (cnt == 7 || cnt == dist+7)
  59                 mach_heartbeat( 0 );
  60
  61             if (++cnt > period) {
  62                 cnt = 0;
  63                 /* The hyperbolic function below modifies the heartbeat period
  64                  * length in dependency of the current (5min) load. It goes
  65                  * through the points f(0)=126, f(1)=86, f(5)=51,
  66                  * f(inf)->30. */
  67                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  68                 dist = period / 4;
  69             }
  70         }
  71 #endif /* CONFIG_HEARTBEAT */
  72         return IRQ_HANDLED;
  73 }
  74
  75 #ifdef CONFIG_M68KCLASSIC
  76 #if !IS_BUILTIN(CONFIG_RTC_DRV_GENERIC)
  77 void read_persistent_clock64(struct timespec64 *ts)
  78 {
  79         struct rtc_time time;
  80
  81         ts->tv_sec = 0;
  82         ts->tv_nsec = 0;
  83
  84         if (!mach_hwclk)
  85                 return;
  86
  87         mach_hwclk(0, &time);
  88
  89         ts->tv_sec = mktime64(time.tm_year + 1900, time.tm_mon + 1, time.tm_mday,
  90                               time.tm_hour, time.tm_min, time.tm_sec);
  91 }
  92 #endif
  93
  94 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
  95 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
  96 {
  97         mach_hwclk(0, tm);
  98         return 0;
  99 }
 100
 101 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
 102 {
 103         if (mach_hwclk(1, tm) < 0)
 104                 return -EOPNOTSUPP;
 105         return 0;
 106 }
 107
 108 static int rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 109 {
 110         struct rtc_pll_info pll;
 111         struct rtc_pll_info __user *argp = (void __user *)arg;
 112
 113         switch (cmd) {
 114         case RTC_PLL_GET:
 115                 if (!mach_get_rtc_pll || mach_get_rtc_pll(&pll))
 116                         return -EINVAL;
 117                 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
 118
 119         case RTC_PLL_SET:
 120                 if (!mach_set_rtc_pll)
 121                         return -EINVAL;
 122                 if (!capable(CAP_SYS_TIME))
 123                         return -EACCES;
 124                 if (copy_from_user(&pll, argp, sizeof(pll)))
 125                         return -EFAULT;
 126                 return mach_set_rtc_pll(&pll);
 127         }
 128
 129         return -ENOIOCTLCMD;
 130 }
 131
 132 static const struct rtc_class_ops generic_rtc_ops = {
 133         .ioctl = rtc_ioctl,
 134         .read_time = rtc_generic_get_time,
 135         .set_time = rtc_generic_set_time,
 136 };
 137
 138 static int __init rtc_init(void)
 139 {
 140         struct platform_device *pdev;
 141
 142         if (!mach_hwclk)
 143                 return -ENODEV;
 144
 145         pdev = platform_device_register_data(NULL, "rtc-generic", -1,
 146                                              &generic_rtc_ops,
 147                                              sizeof(generic_rtc_ops));
 148         return PTR_ERR_OR_ZERO(pdev);
 149 }
 150
 151 module_init(rtc_init);
 152 #endif /* CONFIG_RTC_DRV_GENERIC */
 153 #endif /* CONFIG M68KCLASSIC */
 154
 155 void __init time_init(void)
 156 {
 157         mach_sched_init(timer_interrupt);
 158 }