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 #if defined(CONFIG_M68KCLASSIC) || defined(CONFIG_SUN3)
  66 /* machine dependent timer functions */
  67 int (*mach_hwclk) (int, struct rtc_time*);
  68 EXPORT_SYMBOL(mach_hwclk);
  69
  70 int (*mach_get_rtc_pll)(struct rtc_pll_info *);
  71 int (*mach_set_rtc_pll)(struct rtc_pll_info *);
  72 EXPORT_SYMBOL(mach_get_rtc_pll);
  73 EXPORT_SYMBOL(mach_set_rtc_pll);
  74
  75 #if !IS_BUILTIN(CONFIG_RTC_DRV_GENERIC)
  76 void read_persistent_clock64(struct timespec64 *ts)
  77 {
  78         struct rtc_time time;
  79
  80         ts->tv_sec = 0;
  81         ts->tv_nsec = 0;
  82
  83         if (!mach_hwclk)
  84                 return;
  85
  86         mach_hwclk(0, &time);
  87
  88         ts->tv_sec = mktime64(time.tm_year + 1900, time.tm_mon + 1, time.tm_mday,
  89                               time.tm_hour, time.tm_min, time.tm_sec);
  90 }
  91 #endif
  92
  93 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
  94 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
  95 {
  96         mach_hwclk(0, tm);
  97         return 0;
  98 }
  99
 100 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
 101 {
 102         if (mach_hwclk(1, tm) < 0)
 103                 return -EOPNOTSUPP;
 104         return 0;
 105 }
 106
 107 static int rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 108 {
 109         struct rtc_pll_info pll;
 110         struct rtc_pll_info __user *argp = (void __user *)arg;
 111
 112         switch (cmd) {
 113         case RTC_PLL_GET:
 114                 if (!mach_get_rtc_pll || mach_get_rtc_pll(&pll))
 115                         return -EINVAL;
 116                 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
 117
 118         case RTC_PLL_SET:
 119                 if (!mach_set_rtc_pll)
 120                         return -EINVAL;
 121                 if (!capable(CAP_SYS_TIME))
 122                         return -EACCES;
 123                 if (copy_from_user(&pll, argp, sizeof(pll)))
 124                         return -EFAULT;
 125                 return mach_set_rtc_pll(&pll);
 126         }
 127
 128         return -ENOIOCTLCMD;
 129 }
 130
 131 static const struct rtc_class_ops generic_rtc_ops = {
 132         .ioctl = rtc_ioctl,
 133         .read_time = rtc_generic_get_time,
 134         .set_time = rtc_generic_set_time,
 135 };
 136
 137 static int __init rtc_init(void)
 138 {
 139         struct platform_device *pdev;
 140
 141         if (!mach_hwclk)
 142                 return -ENODEV;
 143
 144         pdev = platform_device_register_data(NULL, "rtc-generic", -1,
 145                                              &generic_rtc_ops,
 146                                              sizeof(generic_rtc_ops));
 147         return PTR_ERR_OR_ZERO(pdev);
 148 }
 149
 150 module_init(rtc_init);
 151 #endif /* CONFIG_RTC_DRV_GENERIC */
 152 #endif /* CONFIG_M68KCLASSIC || SUN3 */
 153
 154 void __init time_init(void)
 155 {
 156         mach_sched_init();
 157 }