LXR linux/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
  35unsigned long (*mach_random_get_entropy)(void);
  36EXPORT_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 */
  43static 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)
  77void 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)
  95static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
  96{
  97        mach_hwclk(0, tm);
  98        return 0;
  99}
 100
 101static 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
 108static 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
 132static 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
 138static 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
 151module_init(rtc_init);
 152#endif /* CONFIG_RTC_DRV_GENERIC */
 153#endif /* CONFIG M68KCLASSIC */
 154
 155void __init time_init(void)
 156{
 157        mach_sched_init(timer_interrupt);
 158}
 159