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
39 /*
40 * timer_interrupt() needs to keep up the real-time clock,
41 * as well as call the "xtime_update()" routine every clocktick
42 */
timer_interrupt(int irq,void * dummy)43 static 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)
read_persistent_clock64(struct timespec64 * ts)77 void 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)
rtc_generic_get_time(struct device * dev,struct rtc_time * tm)95 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
96 {
97 mach_hwclk(0, tm);
98 return 0;
99 }
100
rtc_generic_set_time(struct device * dev,struct rtc_time * tm)101 static 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
rtc_ioctl(struct device * dev,unsigned int cmd,unsigned long arg)108 static 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
132 static 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
rtc_init(void)138 static 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
151 module_init(rtc_init);
152 #endif /* CONFIG_RTC_DRV_GENERIC */
153 #endif /* CONFIG M68KCLASSIC */
154
time_init(void)155 void __init time_init(void)
156 {
157 mach_sched_init(timer_interrupt);
158 }
159
