blob: 86e6538a77b05835b352001d170dba5335be284b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
3 *
4 * Real Time Clock interface for Linux
5 *
6 * TODO: Implement periodic interrupts.
7 *
8 * Copyright (C) 2000 Silicon Graphics, Inc.
9 * Written by Ulf Carlsson (ulfc@engr.sgi.com)
10 *
11 * Based on code written by Paul Gortmaker.
12 *
13 * This driver allows use of the real time clock (built into
14 * nearly all computers) from user space. It exports the /dev/rtc
15 * interface supporting various ioctl() and also the /proc/rtc
16 * pseudo-file for status information.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 *
23 */
24
25#define RTC_VERSION "1.09b"
26
27#include <linux/bcd.h>
28#include <linux/module.h>
29#include <linux/kernel.h>
30#include <linux/types.h>
31#include <linux/miscdevice.h>
32#include <linux/ioport.h>
33#include <linux/fcntl.h>
34#include <linux/rtc.h>
35#include <linux/init.h>
36#include <linux/poll.h>
37#include <linux/proc_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39#include <asm/m48t35.h>
40#include <asm/sn/ioc3.h>
41#include <asm/io.h>
42#include <asm/uaccess.h>
43#include <asm/system.h>
44#include <asm/sn/klconfig.h>
45#include <asm/sn/sn0/ip27.h>
46#include <asm/sn/sn0/hub.h>
47#include <asm/sn/sn_private.h>
48
Cyrill Gorcunov102f4a02008-02-06 01:38:53 -080049static long rtc_ioctl(struct file *filp, unsigned int cmd,
50 unsigned long arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
52static int rtc_read_proc(char *page, char **start, off_t off,
53 int count, int *eof, void *data);
54
55static void get_rtc_time(struct rtc_time *rtc_tm);
56
57/*
58 * Bits in rtc_status. (6 bits of room for future expansion)
59 */
60
61#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
62#define RTC_TIMER_ON 0x02 /* missed irq timer active */
63
64static unsigned char rtc_status; /* bitmapped status byte. */
65static unsigned long rtc_freq; /* Current periodic IRQ rate */
66static struct m48t35_rtc *rtc;
67
68/*
69 * If this driver ever becomes modularised, it will be really nice
70 * to make the epoch retain its value across module reload...
71 */
72
73static unsigned long epoch = 1970; /* year corresponding to 0x00 */
74
75static const unsigned char days_in_mo[] =
76{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
77
Cyrill Gorcunov102f4a02008-02-06 01:38:53 -080078static long rtc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -070079{
80
81 struct rtc_time wtime;
82
83 switch (cmd) {
84 case RTC_RD_TIME: /* Read the time/date from RTC */
85 {
86 get_rtc_time(&wtime);
87 break;
88 }
89 case RTC_SET_TIME: /* Set the RTC */
90 {
91 struct rtc_time rtc_tm;
92 unsigned char mon, day, hrs, min, sec, leap_yr;
93 unsigned int yrs;
94
95 if (!capable(CAP_SYS_TIME))
96 return -EACCES;
97
98 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
99 sizeof(struct rtc_time)))
100 return -EFAULT;
101
102 yrs = rtc_tm.tm_year + 1900;
103 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
104 day = rtc_tm.tm_mday;
105 hrs = rtc_tm.tm_hour;
106 min = rtc_tm.tm_min;
107 sec = rtc_tm.tm_sec;
108
109 if (yrs < 1970)
110 return -EINVAL;
111
112 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
113
114 if ((mon > 12) || (day == 0))
115 return -EINVAL;
116
117 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
118 return -EINVAL;
119
120 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
121 return -EINVAL;
122
123 if ((yrs -= epoch) > 255) /* They are unsigned */
124 return -EINVAL;
125
126 if (yrs > 169)
127 return -EINVAL;
128
129 if (yrs >= 100)
130 yrs -= 100;
131
132 sec = BIN2BCD(sec);
133 min = BIN2BCD(min);
134 hrs = BIN2BCD(hrs);
135 day = BIN2BCD(day);
136 mon = BIN2BCD(mon);
137 yrs = BIN2BCD(yrs);
138
139 spin_lock_irq(&rtc_lock);
140 rtc->control |= M48T35_RTC_SET;
141 rtc->year = yrs;
142 rtc->month = mon;
143 rtc->date = day;
144 rtc->hour = hrs;
145 rtc->min = min;
146 rtc->sec = sec;
147 rtc->control &= ~M48T35_RTC_SET;
148 spin_unlock_irq(&rtc_lock);
149
150 return 0;
151 }
152 default:
153 return -EINVAL;
154 }
155 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
156}
157
158/*
159 * We enforce only one user at a time here with the open/close.
160 * Also clear the previous interrupt data on an open, and clean
161 * up things on a close.
162 */
163
164static int rtc_open(struct inode *inode, struct file *file)
165{
166 spin_lock_irq(&rtc_lock);
167
168 if (rtc_status & RTC_IS_OPEN) {
169 spin_unlock_irq(&rtc_lock);
170 return -EBUSY;
171 }
172
173 rtc_status |= RTC_IS_OPEN;
174 spin_unlock_irq(&rtc_lock);
175
176 return 0;
177}
178
179static int rtc_release(struct inode *inode, struct file *file)
180{
181 /*
182 * Turn off all interrupts once the device is no longer
183 * in use, and clear the data.
184 */
185
186 spin_lock_irq(&rtc_lock);
187 rtc_status &= ~RTC_IS_OPEN;
188 spin_unlock_irq(&rtc_lock);
189
190 return 0;
191}
192
193/*
194 * The various file operations we support.
195 */
196
Arjan van de Ven62322d22006-07-03 00:24:21 -0700197static const struct file_operations rtc_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 .owner = THIS_MODULE,
Cyrill Gorcunov102f4a02008-02-06 01:38:53 -0800199 .unlocked_ioctl = rtc_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 .open = rtc_open,
201 .release = rtc_release,
202};
203
204static struct miscdevice rtc_dev=
205{
206 RTC_MINOR,
207 "rtc",
208 &rtc_fops
209};
210
211static int __init rtc_init(void)
212{
213 rtc = (struct m48t35_rtc *)
214 (KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base + IOC3_BYTEBUS_DEV0);
215
216 printk(KERN_INFO "Real Time Clock Driver v%s\n", RTC_VERSION);
217 if (misc_register(&rtc_dev)) {
218 printk(KERN_ERR "rtc: cannot register misc device.\n");
219 return -ENODEV;
220 }
221 if (!create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)) {
222 printk(KERN_ERR "rtc: cannot create /proc/rtc.\n");
223 misc_deregister(&rtc_dev);
224 return -ENOENT;
225 }
226
227 rtc_freq = 1024;
228
229 return 0;
230}
231
232static void __exit rtc_exit (void)
233{
234 /* interrupts and timer disabled at this point by rtc_release */
235
236 remove_proc_entry ("rtc", NULL);
237 misc_deregister(&rtc_dev);
238}
239
240module_init(rtc_init);
241module_exit(rtc_exit);
242
243/*
244 * Info exported via "/proc/rtc".
245 */
246
247static int rtc_get_status(char *buf)
248{
249 char *p;
250 struct rtc_time tm;
251
252 /*
253 * Just emulate the standard /proc/rtc
254 */
255
256 p = buf;
257
258 get_rtc_time(&tm);
259
260 /*
261 * There is no way to tell if the luser has the RTC set for local
262 * time or for Universal Standard Time (GMT). Probably local though.
263 */
264 p += sprintf(p,
265 "rtc_time\t: %02d:%02d:%02d\n"
266 "rtc_date\t: %04d-%02d-%02d\n"
267 "rtc_epoch\t: %04lu\n"
268 "24hr\t\t: yes\n",
269 tm.tm_hour, tm.tm_min, tm.tm_sec,
270 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
271
272 return p - buf;
273}
274
275static int rtc_read_proc(char *page, char **start, off_t off,
276 int count, int *eof, void *data)
277{
278 int len = rtc_get_status(page);
279 if (len <= off+count) *eof = 1;
280 *start = page + off;
281 len -= off;
282 if (len>count) len = count;
283 if (len<0) len = 0;
284 return len;
285}
286
287static void get_rtc_time(struct rtc_time *rtc_tm)
288{
289 /*
290 * Do we need to wait for the last update to finish?
291 */
292
293 /*
294 * Only the values that we read from the RTC are set. We leave
295 * tm_wday, tm_yday and tm_isdst untouched. Even though the
296 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
297 * by the RTC when initially set to a non-zero value.
298 */
299 spin_lock_irq(&rtc_lock);
300 rtc->control |= M48T35_RTC_READ;
301 rtc_tm->tm_sec = rtc->sec;
302 rtc_tm->tm_min = rtc->min;
303 rtc_tm->tm_hour = rtc->hour;
304 rtc_tm->tm_mday = rtc->date;
305 rtc_tm->tm_mon = rtc->month;
306 rtc_tm->tm_year = rtc->year;
307 rtc->control &= ~M48T35_RTC_READ;
308 spin_unlock_irq(&rtc_lock);
309
310 rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
311 rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
312 rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
313 rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
314 rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
315 rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
316
317 /*
318 * Account for differences between how the RTC uses the values
319 * and how they are defined in a struct rtc_time;
320 */
321 if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
322 rtc_tm->tm_year += 100;
323
324 rtc_tm->tm_mon--;
325}