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 #ifdef CONFIG_HEARTBEAT
  39 void timer_heartbeat(void)
  40 {
  41         /* use power LED as a heartbeat instead -- much more useful
  42            for debugging -- based on the version for PReP by Cort */
  43         /* acts like an actual heart beat -- ie thump-thump-pause... */
  44         if (mach_heartbeat) {
  45             static unsigned cnt = 0, period = 0, dist = 0;
  46
  47             if (cnt == 0 || cnt == dist)
  48                 mach_heartbeat( 1 );
  49             else if (cnt == 7 || cnt == dist+7)
  50                 mach_heartbeat( 0 );
  51
  52             if (++cnt > period) {
  53                 cnt = 0;
  54                 /* The hyperbolic function below modifies the heartbeat period
  55                  * length in dependency of the current (5min) load. It goes
  56                  * through the points f(0)=126, f(1)=86, f(5)=51,
  57                  * f(inf)->30. */
  58                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  59                 dist = period / 4;
  60             }
  61         }
  62 }
  63 #endif /* CONFIG_HEARTBEAT */
  64
  65 #ifdef CONFIG_M68KCLASSIC
  66 #if !IS_BUILTIN(CONFIG_RTC_DRV_GENERIC)
  67 void read_persistent_clock64(struct timespec64 *ts)
  68 {
  69         struct rtc_time time;
  70
  71         ts->tv_sec = 0;
  72         ts->tv_nsec = 0;
  73
  74         if (!mach_hwclk)
  75                 return;
  76
  77         mach_hwclk(0, &time);
  78
  79         ts->tv_sec = mktime64(time.tm_year + 1900, time.tm_mon + 1, time.tm_mday,
  80                               time.tm_hour, time.tm_min, time.tm_sec);
  81 }
  82 #endif
  83
  84 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
  85 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
  86 {
  87         mach_hwclk(0, tm);
  88         return 0;
  89 }
  90
  91 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
  92 {
  93         if (mach_hwclk(1, tm) < 0)
  94                 return -EOPNOTSUPP;
  95         return 0;
  96 }
  97
  98 static int rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
  99 {
 100         struct rtc_pll_info pll;
 101         struct rtc_pll_info __user *argp = (void __user *)arg;
 102
 103         switch (cmd) {
 104         case RTC_PLL_GET:
 105                 if (!mach_get_rtc_pll || mach_get_rtc_pll(&pll))
 106                         return -EINVAL;
 107                 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
 108
 109         case RTC_PLL_SET:
 110                 if (!mach_set_rtc_pll)
 111                         return -EINVAL;
 112                 if (!capable(CAP_SYS_TIME))
 113                         return -EACCES;
 114                 if (copy_from_user(&pll, argp, sizeof(pll)))
 115                         return -EFAULT;
 116                 return mach_set_rtc_pll(&pll);
 117         }
 118
 119         return -ENOIOCTLCMD;
 120 }
 121
 122 static const struct rtc_class_ops generic_rtc_ops = {
 123         .ioctl = rtc_ioctl,
 124         .read_time = rtc_generic_get_time,
 125         .set_time = rtc_generic_set_time,
 126 };
 127
 128 static int __init rtc_init(void)
 129 {
 130         struct platform_device *pdev;
 131
 132         if (!mach_hwclk)
 133                 return -ENODEV;
 134
 135         pdev = platform_device_register_data(NULL, "rtc-generic", -1,
 136                                              &generic_rtc_ops,
 137                                              sizeof(generic_rtc_ops));
 138         return PTR_ERR_OR_ZERO(pdev);
 139 }
 140
 141 module_init(rtc_init);
 142 #endif /* CONFIG_RTC_DRV_GENERIC */
 143 #endif /* CONFIG M68KCLASSIC */
 144
 145 void __init time_init(void)
 146 {
 147         mach_sched_init();
 148 }