1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Real Time Clock interface for Linux on the BVME6000
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/module.h>
19 #include <linux/rtc.h> /* For struct rtc_time and ioctls, etc */
20 #include <linux/bcd.h>
21 #include <asm/bvme6000hw.h>
22
23 #include <asm/io.h>
24 #include <linux/uaccess.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 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_status = ATOMIC_INIT(1);
38
39 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
40 {
41 volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
42 unsigned char msr;
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 msr = rtc->msr & 0xc0;
53 rtc->msr = 0x40;
54 memset(&wtime, 0, sizeof(struct rtc_time));
55 do {
56 wtime.tm_sec = bcd2bin(rtc->bcd_sec);
57 wtime.tm_min = bcd2bin(rtc->bcd_min);
58 wtime.tm_hour = bcd2bin(rtc->bcd_hr);
59 wtime.tm_mday = bcd2bin(rtc->bcd_dom);
60 wtime.tm_mon = bcd2bin(rtc->bcd_mth)-1;
61 wtime.tm_year = bcd2bin(rtc->bcd_year);
62 if (wtime.tm_year < 70)
63 wtime.tm_year += 100;
64 wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
65 } while (wtime.tm_sec != bcd2bin(rtc->bcd_sec));
66 rtc->msr = msr;
67 local_irq_restore(flags);
68 return copy_to_user(argp, &wtime, sizeof wtime) ?
69 -EFAULT : 0;
70 }
71 case RTC_SET_TIME: /* Set the RTC */
72 {
73 struct rtc_time rtc_tm;
74 unsigned char mon, day, hrs, min, sec, leap_yr;
75 unsigned int yrs;
76
77 if (!capable(CAP_SYS_ADMIN))
78 return -EACCES;
79
80 if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
81 return -EFAULT;
82
83 yrs = rtc_tm.tm_year;
84 if (yrs < 1900)
85 yrs += 1900;
86 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
87 day = rtc_tm.tm_mday;
88 hrs = rtc_tm.tm_hour;
89 min = rtc_tm.tm_min;
90 sec = rtc_tm.tm_sec;
91
92 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
93
94 if ((mon > 12) || (mon < 1) || (day == 0))
95 return -EINVAL;
96
97 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
98 return -EINVAL;
99
100 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
101 return -EINVAL;
102
103 if (yrs >= 2070)
104 return -EINVAL;
105
106 local_irq_save(flags);
107 /* Ensure clock and real-time-mode-register are accessible */
108 msr = rtc->msr & 0xc0;
109 rtc->msr = 0x40;
110
111 rtc->t0cr_rtmr = yrs%4;
112 rtc->bcd_tenms = 0;
113 rtc->bcd_sec = bin2bcd(sec);
114 rtc->bcd_min = bin2bcd(min);
115 rtc->bcd_hr = bin2bcd(hrs);
116 rtc->bcd_dom = bin2bcd(day);
117 rtc->bcd_mth = bin2bcd(mon);
118 rtc->bcd_year = bin2bcd(yrs%100);
119 if (rtc_tm.tm_wday >= 0)
120 rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1);
121 rtc->t0cr_rtmr = yrs%4 | 0x08;
122
123 rtc->msr = msr;
124 local_irq_restore(flags);
125 return 0;
126 }
127 default:
128 return -EINVAL;
129 }
130 }
131
132 /*
133 * We enforce only one user at a time here with the open/close.
134 */
135 static int rtc_open(struct inode *inode, struct file *file)
136 {
137 if (!atomic_dec_and_test(&rtc_status)) {
138 atomic_inc(&rtc_status);
139 return -EBUSY;
140 }
141 return 0;
142 }
143
144 static int rtc_release(struct inode *inode, struct file *file)
145 {
146 atomic_inc(&rtc_status);
147 return 0;
148 }
149
150 /*
151 * The various file operations we support.
152 */
153
154 static const struct file_operations rtc_fops = {
155 .unlocked_ioctl = rtc_ioctl,
156 .open = rtc_open,
157 .release = rtc_release,
158 .llseek = noop_llseek,
159 };
160
161 static struct miscdevice rtc_dev = {
162 .minor = RTC_MINOR,
163 .name = "rtc",
164 .fops = &rtc_fops
165 };
166
167 static int __init rtc_DP8570A_init(void)
168 {
169 if (!MACH_IS_BVME6000)
170 return -ENODEV;
171
172 pr_info("DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
173 return misc_register(&rtc_dev);
174 }
175 module_init(rtc_DP8570A_init);
176
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