xref: /openbmc/linux/arch/m68k/kernel/time.c (revision 82e6fdd6)
1 /*
2  *  linux/arch/m68k/kernel/time.c
3  *
4  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
5  *
6  * This file contains the m68k-specific time handling details.
7  * Most of the stuff is located in the machine specific files.
8  *
9  * 1997-09-10	Updated NTP code according to technical memorandum Jan '96
10  *		"A Kernel Model for Precision Timekeeping" by Dave Mills
11  */
12 
13 #include <linux/errno.h>
14 #include <linux/export.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/sched/loadavg.h>
18 #include <linux/kernel.h>
19 #include <linux/param.h>
20 #include <linux/string.h>
21 #include <linux/mm.h>
22 #include <linux/rtc.h>
23 #include <linux/platform_device.h>
24 
25 #include <asm/machdep.h>
26 #include <asm/io.h>
27 #include <asm/irq_regs.h>
28 
29 #include <linux/time.h>
30 #include <linux/timex.h>
31 #include <linux/profile.h>
32 
33 
34 unsigned long (*mach_random_get_entropy)(void);
35 EXPORT_SYMBOL_GPL(mach_random_get_entropy);
36 
37 
38 /*
39  * timer_interrupt() needs to keep up the real-time clock,
40  * as well as call the "xtime_update()" routine every clocktick
41  */
42 static irqreturn_t timer_interrupt(int irq, void *dummy)
43 {
44 	xtime_update(1);
45 	update_process_times(user_mode(get_irq_regs()));
46 	profile_tick(CPU_PROFILING);
47 
48 #ifdef CONFIG_HEARTBEAT
49 	/* use power LED as a heartbeat instead -- much more useful
50 	   for debugging -- based on the version for PReP by Cort */
51 	/* acts like an actual heart beat -- ie thump-thump-pause... */
52 	if (mach_heartbeat) {
53 	    static unsigned cnt = 0, period = 0, dist = 0;
54 
55 	    if (cnt == 0 || cnt == dist)
56 		mach_heartbeat( 1 );
57 	    else if (cnt == 7 || cnt == dist+7)
58 		mach_heartbeat( 0 );
59 
60 	    if (++cnt > period) {
61 		cnt = 0;
62 		/* The hyperbolic function below modifies the heartbeat period
63 		 * length in dependency of the current (5min) load. It goes
64 		 * through the points f(0)=126, f(1)=86, f(5)=51,
65 		 * f(inf)->30. */
66 		period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
67 		dist = period / 4;
68 	    }
69 	}
70 #endif /* CONFIG_HEARTBEAT */
71 	return IRQ_HANDLED;
72 }
73 
74 void read_persistent_clock(struct timespec *ts)
75 {
76 	struct rtc_time time;
77 	ts->tv_sec = 0;
78 	ts->tv_nsec = 0;
79 
80 	if (mach_hwclk) {
81 		mach_hwclk(0, &time);
82 
83 		if ((time.tm_year += 1900) < 1970)
84 			time.tm_year += 100;
85 		ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
86 				      time.tm_hour, time.tm_min, time.tm_sec);
87 	}
88 }
89 
90 #if defined(CONFIG_ARCH_USES_GETTIMEOFFSET) && IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
91 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
92 {
93 	mach_hwclk(0, tm);
94 	return rtc_valid_tm(tm);
95 }
96 
97 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
98 {
99 	if (mach_hwclk(1, tm) < 0)
100 		return -EOPNOTSUPP;
101 	return 0;
102 }
103 
104 static int rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
105 {
106 	struct rtc_pll_info pll;
107 	struct rtc_pll_info __user *argp = (void __user *)arg;
108 
109 	switch (cmd) {
110 	case RTC_PLL_GET:
111 		if (!mach_get_rtc_pll || mach_get_rtc_pll(&pll))
112 			return -EINVAL;
113 		return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
114 
115 	case RTC_PLL_SET:
116 		if (!mach_set_rtc_pll)
117 			return -EINVAL;
118 		if (!capable(CAP_SYS_TIME))
119 			return -EACCES;
120 		if (copy_from_user(&pll, argp, sizeof(pll)))
121 			return -EFAULT;
122 		return mach_set_rtc_pll(&pll);
123 	}
124 
125 	return -ENOIOCTLCMD;
126 }
127 
128 static const struct rtc_class_ops generic_rtc_ops = {
129 	.ioctl = rtc_ioctl,
130 	.read_time = rtc_generic_get_time,
131 	.set_time = rtc_generic_set_time,
132 };
133 
134 static int __init rtc_init(void)
135 {
136 	struct platform_device *pdev;
137 
138 	if (!mach_hwclk)
139 		return -ENODEV;
140 
141 	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
142 					     &generic_rtc_ops,
143 					     sizeof(generic_rtc_ops));
144 	return PTR_ERR_OR_ZERO(pdev);
145 }
146 
147 module_init(rtc_init);
148 
149 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
150 
151 void __init time_init(void)
152 {
153 	mach_sched_init(timer_interrupt);
154 }
155