arch/m68k/kernel/time.c

   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 }