1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *	Real Time Clock interface for Linux on the MVME16x
4  *
5  * Based on the PC driver by Paul Gortmaker.
6  */
7 
8 #define RTC_VERSION		"1.00"
9 
10 #include <linux/types.h>
11 #include <linux/errno.h>
12 #include <linux/miscdevice.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/rtc.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 <linux/uaccess.h>
24 #include <asm/setup.h>
25 
26 /*
27  *	We sponge a minor off of the misc major. No need slurping
28  *	up another valuable major dev number for this. If you add
29  *	an ioctl, make sure you don't conflict with SPARC's RTC
30  *	ioctls.
31  */
32 
33 static const unsigned char days_in_mo[] =
34 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
35 
36 static atomic_t rtc_ready = ATOMIC_INIT(1);
37 
rtc_ioctl(struct file * file,unsigned int cmd,unsigned long arg)38 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
39 {
40 	volatile MK48T08ptr_t rtc = (MK48T08ptr_t)MVME_RTC_BASE;
41 	unsigned long flags;
42 	struct rtc_time wtime;
43 	void __user *argp = (void __user *)arg;
44 
45 	switch (cmd) {
46 	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
47 	{
48 		local_irq_save(flags);
49 		/* Ensure clock and real-time-mode-register are accessible */
50 		rtc->ctrl = RTC_READ;
51 		memset(&wtime, 0, sizeof(struct rtc_time));
52 		wtime.tm_sec =  bcd2bin(rtc->bcd_sec);
53 		wtime.tm_min =  bcd2bin(rtc->bcd_min);
54 		wtime.tm_hour = bcd2bin(rtc->bcd_hr);
55 		wtime.tm_mday =  bcd2bin(rtc->bcd_dom);
56 		wtime.tm_mon =  bcd2bin(rtc->bcd_mth)-1;
57 		wtime.tm_year = bcd2bin(rtc->bcd_year);
58 		if (wtime.tm_year < 70)
59 			wtime.tm_year += 100;
60 		wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
61 		rtc->ctrl = 0;
62 		local_irq_restore(flags);
63 		return copy_to_user(argp, &wtime, sizeof wtime) ?
64 								-EFAULT : 0;
65 	}
66 	case RTC_SET_TIME:	/* Set the RTC */
67 	{
68 		struct rtc_time rtc_tm;
69 		unsigned char mon, day, hrs, min, sec, leap_yr;
70 		unsigned int yrs;
71 
72 		if (!capable(CAP_SYS_ADMIN))
73 			return -EACCES;
74 
75 		if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
76 			return -EFAULT;
77 
78 		yrs = rtc_tm.tm_year;
79 		if (yrs < 1900)
80 			yrs += 1900;
81 		mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
82 		day = rtc_tm.tm_mday;
83 		hrs = rtc_tm.tm_hour;
84 		min = rtc_tm.tm_min;
85 		sec = rtc_tm.tm_sec;
86 
87 		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
88 
89 		if ((mon > 12) || (day == 0))
90 			return -EINVAL;
91 
92 		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
93 			return -EINVAL;
94 
95 		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
96 			return -EINVAL;
97 
98 		if (yrs >= 2070)
99 			return -EINVAL;
100 
101 		local_irq_save(flags);
102 		rtc->ctrl     = RTC_WRITE;
103 
104 		rtc->bcd_sec  = bin2bcd(sec);
105 		rtc->bcd_min  = bin2bcd(min);
106 		rtc->bcd_hr   = bin2bcd(hrs);
107 		rtc->bcd_dom  = bin2bcd(day);
108 		rtc->bcd_mth  = bin2bcd(mon);
109 		rtc->bcd_year = bin2bcd(yrs%100);
110 
111 		rtc->ctrl     = 0;
112 		local_irq_restore(flags);
113 		return 0;
114 	}
115 	default:
116 		return -EINVAL;
117 	}
118 }
119 
120 /*
121  * We enforce only one user at a time here with the open/close.
122  */
rtc_open(struct inode * inode,struct file * file)123 static int rtc_open(struct inode *inode, struct file *file)
124 {
125 	if( !atomic_dec_and_test(&rtc_ready) )
126 	{
127 		atomic_inc( &rtc_ready );
128 		return -EBUSY;
129 	}
130 	return 0;
131 }
132 
rtc_release(struct inode * inode,struct file * file)133 static int rtc_release(struct inode *inode, struct file *file)
134 {
135 	atomic_inc( &rtc_ready );
136 	return 0;
137 }
138 
139 /*
140  *	The various file operations we support.
141  */
142 
143 static const struct file_operations rtc_fops = {
144 	.unlocked_ioctl	= rtc_ioctl,
145 	.open		= rtc_open,
146 	.release	= rtc_release,
147 	.llseek		= noop_llseek,
148 };
149 
150 static struct miscdevice rtc_dev=
151 {
152 	.minor =	RTC_MINOR,
153 	.name =		"rtc",
154 	.fops =		&rtc_fops
155 };
156 
rtc_MK48T08_init(void)157 static int __init rtc_MK48T08_init(void)
158 {
159 	if (!MACH_IS_MVME16x)
160 		return -ENODEV;
161 
162 	pr_info("MK48T08 Real Time Clock Driver v%s\n", RTC_VERSION);
163 	return misc_register(&rtc_dev);
164 }
165 device_initcall(rtc_MK48T08_init);
166