1 // SPDX-License-Identifier: GPL-2.0
3 * Real Time Clock interface for Linux on the BVME6000
5 * Based on the PC driver by Paul Gortmaker.
8 #define RTC_VERSION "1.00"
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>
24 #include <linux/uaccess.h>
25 #include <asm/setup.h>
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
34 static unsigned char days_in_mo[] =
35 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
37 static atomic_t rtc_status = ATOMIC_INIT(1);
39 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
41 volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
44 struct rtc_time wtime;
45 void __user *argp = (void __user *)arg;
48 case RTC_RD_TIME: /* Read the time/date from RTC */
50 local_irq_save(flags);
51 /* Ensure clock and real-time-mode-register are accessible */
52 msr = rtc->msr & 0xc0;
54 memset(&wtime, 0, sizeof(struct rtc_time));
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)
64 wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
65 } while (wtime.tm_sec != bcd2bin(rtc->bcd_sec));
67 local_irq_restore(flags);
68 return copy_to_user(argp, &wtime, sizeof wtime) ?
71 case RTC_SET_TIME: /* Set the RTC */
73 struct rtc_time rtc_tm;
74 unsigned char mon, day, hrs, min, sec, leap_yr;
77 if (!capable(CAP_SYS_ADMIN))
80 if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
86 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
92 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
94 if ((mon > 12) || (mon < 1) || (day == 0))
97 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
100 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
106 local_irq_save(flags);
107 /* Ensure clock and real-time-mode-register are accessible */
108 msr = rtc->msr & 0xc0;
111 rtc->t0cr_rtmr = yrs%4;
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;
124 local_irq_restore(flags);
133 * We enforce only one user at a time here with the open/close.
135 static int rtc_open(struct inode *inode, struct file *file)
137 if (!atomic_dec_and_test(&rtc_status)) {
138 atomic_inc(&rtc_status);
144 static int rtc_release(struct inode *inode, struct file *file)
146 atomic_inc(&rtc_status);
151 * The various file operations we support.
154 static const struct file_operations rtc_fops = {
155 .unlocked_ioctl = rtc_ioctl,
157 .release = rtc_release,
158 .llseek = noop_llseek,
161 static struct miscdevice rtc_dev = {
167 static int __init rtc_DP8570A_init(void)
169 if (!MACH_IS_BVME6000)
172 pr_info("DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
173 return misc_register(&rtc_dev);
175 module_init(rtc_DP8570A_init);