xref: /openbmc/linux/arch/m68k/kernel/time.c (revision b3821150)
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
timer_heartbeat(void)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 /* 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)
read_persistent_clock64(struct timespec64 * ts)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)
rtc_generic_get_time(struct device * dev,struct rtc_time * tm)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 
rtc_generic_set_time(struct device * dev,struct rtc_time * tm)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 
rtc_ioctl(struct device * dev,unsigned int cmd,unsigned long arg)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 
rtc_init(void)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 */
153 
time_init(void)154 void __init time_init(void)
155 {
156 	mach_sched_init();
157 }
158