LXR linux/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
  34unsigned long (*mach_random_get_entropy)(void);
  35EXPORT_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 */
  42static 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
  74void 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)
  91static 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
  97static 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
 104static 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
 128static 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
 134static 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
 147module_init(rtc_init);
 148
 149#endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
 150
 151void __init time_init(void)
 152{
 153        mach_sched_init(timer_interrupt);
 154}
 155