xref: /openbmc/linux/arch/m68k/mvme16x/rtc.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  *	Real Time Clock interface for Linux on the MVME16x
3  *
4  * Based on the PC driver by Paul Gortmaker.
5  */
6 
7 #define RTC_VERSION		"1.00"
8 
9 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/miscdevice.h>
12 #include <linux/slab.h>
13 #include <linux/ioport.h>
14 #include <linux/capability.h>
15 #include <linux/fcntl.h>
16 #include <linux/init.h>
17 #include <linux/poll.h>
18 #include <linux/mc146818rtc.h>	/* For struct rtc_time and ioctls, etc */
19 #include <linux/bcd.h>
20 #include <asm/mvme16xhw.h>
21 
22 #include <asm/io.h>
23 #include <asm/uaccess.h>
24 #include <asm/system.h>
25 #include <asm/setup.h>
26 
27 /*
28  *	We sponge a minor off of the misc major. No need slurping
29  *	up another valuable major dev number for this. If you add
30  *	an ioctl, make sure you don't conflict with SPARC's RTC
31  *	ioctls.
32  */
33 
34 static const unsigned char days_in_mo[] =
35 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
36 
37 static atomic_t rtc_ready = ATOMIC_INIT(1);
38 
39 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
40 		     unsigned long arg)
41 {
42 	volatile MK48T08ptr_t rtc = (MK48T08ptr_t)MVME_RTC_BASE;
43 	unsigned long flags;
44 	struct rtc_time wtime;
45 	void __user *argp = (void __user *)arg;
46 
47 	switch (cmd) {
48 	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
49 	{
50 		local_irq_save(flags);
51 		/* Ensure clock and real-time-mode-register are accessible */
52 		rtc->ctrl = RTC_READ;
53 		memset(&wtime, 0, sizeof(struct rtc_time));
54 		wtime.tm_sec =  BCD2BIN(rtc->bcd_sec);
55 		wtime.tm_min =  BCD2BIN(rtc->bcd_min);
56 		wtime.tm_hour = BCD2BIN(rtc->bcd_hr);
57 		wtime.tm_mday =  BCD2BIN(rtc->bcd_dom);
58 		wtime.tm_mon =  BCD2BIN(rtc->bcd_mth)-1;
59 		wtime.tm_year = BCD2BIN(rtc->bcd_year);
60 		if (wtime.tm_year < 70)
61 			wtime.tm_year += 100;
62 		wtime.tm_wday = BCD2BIN(rtc->bcd_dow)-1;
63 		rtc->ctrl = 0;
64 		local_irq_restore(flags);
65 		return copy_to_user(argp, &wtime, sizeof wtime) ?
66 								-EFAULT : 0;
67 	}
68 	case RTC_SET_TIME:	/* Set the RTC */
69 	{
70 		struct rtc_time rtc_tm;
71 		unsigned char mon, day, hrs, min, sec, leap_yr;
72 		unsigned int yrs;
73 
74 		if (!capable(CAP_SYS_ADMIN))
75 			return -EACCES;
76 
77 		if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
78 			return -EFAULT;
79 
80 		yrs = rtc_tm.tm_year;
81 		if (yrs < 1900)
82 			yrs += 1900;
83 		mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
84 		day = rtc_tm.tm_mday;
85 		hrs = rtc_tm.tm_hour;
86 		min = rtc_tm.tm_min;
87 		sec = rtc_tm.tm_sec;
88 
89 		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
90 
91 		if ((mon > 12) || (day == 0))
92 			return -EINVAL;
93 
94 		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
95 			return -EINVAL;
96 
97 		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
98 			return -EINVAL;
99 
100 		if (yrs >= 2070)
101 			return -EINVAL;
102 
103 		local_irq_save(flags);
104 		rtc->ctrl     = RTC_WRITE;
105 
106 		rtc->bcd_sec  = BIN2BCD(sec);
107 		rtc->bcd_min  = BIN2BCD(min);
108 		rtc->bcd_hr   = BIN2BCD(hrs);
109 		rtc->bcd_dom  = BIN2BCD(day);
110 		rtc->bcd_mth  = BIN2BCD(mon);
111 		rtc->bcd_year = BIN2BCD(yrs%100);
112 
113 		rtc->ctrl     = 0;
114 		local_irq_restore(flags);
115 		return 0;
116 	}
117 	default:
118 		return -EINVAL;
119 	}
120 }
121 
122 /*
123  *	We enforce only one user at a time here with the open/close.
124  *	Also clear the previous interrupt data on an open, and clean
125  *	up things on a close.
126  */
127 
128 static int rtc_open(struct inode *inode, struct file *file)
129 {
130 	if( !atomic_dec_and_test(&rtc_ready) )
131 	{
132 		atomic_inc( &rtc_ready );
133 		return -EBUSY;
134 	}
135 
136 	return 0;
137 }
138 
139 static int rtc_release(struct inode *inode, struct file *file)
140 {
141 	atomic_inc( &rtc_ready );
142 	return 0;
143 }
144 
145 /*
146  *	The various file operations we support.
147  */
148 
149 static const struct file_operations rtc_fops = {
150 	.ioctl =	rtc_ioctl,
151 	.open =		rtc_open,
152 	.release =	rtc_release,
153 };
154 
155 static struct miscdevice rtc_dev=
156 {
157 	.minor =	RTC_MINOR,
158 	.name =		"rtc",
159 	.fops =		&rtc_fops
160 };
161 
162 static int __init rtc_MK48T08_init(void)
163 {
164 	if (!MACH_IS_MVME16x)
165 		return -ENODEV;
166 
167 	printk(KERN_INFO "MK48T08 Real Time Clock Driver v%s\n", RTC_VERSION);
168 	return misc_register(&rtc_dev);
169 }
170 module_init(rtc_MK48T08_init);
171