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
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 */
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
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
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
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