ia64/linux-2.6.18-xen.hg

view drivers/char/ip27-rtc.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
1 /*
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 */
25 #define RTC_VERSION "1.09b"
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>
38 #include <linux/smp_lock.h>
40 #include <asm/m48t35.h>
41 #include <asm/sn/ioc3.h>
42 #include <asm/io.h>
43 #include <asm/uaccess.h>
44 #include <asm/system.h>
45 #include <asm/sn/klconfig.h>
46 #include <asm/sn/sn0/ip27.h>
47 #include <asm/sn/sn0/hub.h>
48 #include <asm/sn/sn_private.h>
50 static int rtc_ioctl(struct inode *inode, struct file *file,
51 unsigned int cmd, unsigned long arg);
53 static int rtc_read_proc(char *page, char **start, off_t off,
54 int count, int *eof, void *data);
56 static void get_rtc_time(struct rtc_time *rtc_tm);
58 /*
59 * Bits in rtc_status. (6 bits of room for future expansion)
60 */
62 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
63 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
65 static unsigned char rtc_status; /* bitmapped status byte. */
66 static unsigned long rtc_freq; /* Current periodic IRQ rate */
67 static struct m48t35_rtc *rtc;
69 /*
70 * If this driver ever becomes modularised, it will be really nice
71 * to make the epoch retain its value across module reload...
72 */
74 static unsigned long epoch = 1970; /* year corresponding to 0x00 */
76 static const unsigned char days_in_mo[] =
77 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
79 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
80 unsigned long arg)
81 {
83 struct rtc_time wtime;
85 switch (cmd) {
86 case RTC_RD_TIME: /* Read the time/date from RTC */
87 {
88 get_rtc_time(&wtime);
89 break;
90 }
91 case RTC_SET_TIME: /* Set the RTC */
92 {
93 struct rtc_time rtc_tm;
94 unsigned char mon, day, hrs, min, sec, leap_yr;
95 unsigned int yrs;
97 if (!capable(CAP_SYS_TIME))
98 return -EACCES;
100 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
101 sizeof(struct rtc_time)))
102 return -EFAULT;
104 yrs = rtc_tm.tm_year + 1900;
105 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
106 day = rtc_tm.tm_mday;
107 hrs = rtc_tm.tm_hour;
108 min = rtc_tm.tm_min;
109 sec = rtc_tm.tm_sec;
111 if (yrs < 1970)
112 return -EINVAL;
114 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
116 if ((mon > 12) || (day == 0))
117 return -EINVAL;
119 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
120 return -EINVAL;
122 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
123 return -EINVAL;
125 if ((yrs -= epoch) > 255) /* They are unsigned */
126 return -EINVAL;
128 if (yrs > 169)
129 return -EINVAL;
131 if (yrs >= 100)
132 yrs -= 100;
134 sec = BIN2BCD(sec);
135 min = BIN2BCD(min);
136 hrs = BIN2BCD(hrs);
137 day = BIN2BCD(day);
138 mon = BIN2BCD(mon);
139 yrs = BIN2BCD(yrs);
141 spin_lock_irq(&rtc_lock);
142 rtc->control |= M48T35_RTC_SET;
143 rtc->year = yrs;
144 rtc->month = mon;
145 rtc->date = day;
146 rtc->hour = hrs;
147 rtc->min = min;
148 rtc->sec = sec;
149 rtc->control &= ~M48T35_RTC_SET;
150 spin_unlock_irq(&rtc_lock);
152 return 0;
153 }
154 default:
155 return -EINVAL;
156 }
157 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
158 }
160 /*
161 * We enforce only one user at a time here with the open/close.
162 * Also clear the previous interrupt data on an open, and clean
163 * up things on a close.
164 */
166 static int rtc_open(struct inode *inode, struct file *file)
167 {
168 spin_lock_irq(&rtc_lock);
170 if (rtc_status & RTC_IS_OPEN) {
171 spin_unlock_irq(&rtc_lock);
172 return -EBUSY;
173 }
175 rtc_status |= RTC_IS_OPEN;
176 spin_unlock_irq(&rtc_lock);
178 return 0;
179 }
181 static int rtc_release(struct inode *inode, struct file *file)
182 {
183 /*
184 * Turn off all interrupts once the device is no longer
185 * in use, and clear the data.
186 */
188 spin_lock_irq(&rtc_lock);
189 rtc_status &= ~RTC_IS_OPEN;
190 spin_unlock_irq(&rtc_lock);
192 return 0;
193 }
195 /*
196 * The various file operations we support.
197 */
199 static const struct file_operations rtc_fops = {
200 .owner = THIS_MODULE,
201 .ioctl = rtc_ioctl,
202 .open = rtc_open,
203 .release = rtc_release,
204 };
206 static struct miscdevice rtc_dev=
207 {
208 RTC_MINOR,
209 "rtc",
210 &rtc_fops
211 };
213 static int __init rtc_init(void)
214 {
215 rtc = (struct m48t35_rtc *)
216 (KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base + IOC3_BYTEBUS_DEV0);
218 printk(KERN_INFO "Real Time Clock Driver v%s\n", RTC_VERSION);
219 if (misc_register(&rtc_dev)) {
220 printk(KERN_ERR "rtc: cannot register misc device.\n");
221 return -ENODEV;
222 }
223 if (!create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)) {
224 printk(KERN_ERR "rtc: cannot create /proc/rtc.\n");
225 misc_deregister(&rtc_dev);
226 return -ENOENT;
227 }
229 rtc_freq = 1024;
231 return 0;
232 }
234 static void __exit rtc_exit (void)
235 {
236 /* interrupts and timer disabled at this point by rtc_release */
238 remove_proc_entry ("rtc", NULL);
239 misc_deregister(&rtc_dev);
240 }
242 module_init(rtc_init);
243 module_exit(rtc_exit);
245 /*
246 * Info exported via "/proc/rtc".
247 */
249 static int rtc_get_status(char *buf)
250 {
251 char *p;
252 struct rtc_time tm;
254 /*
255 * Just emulate the standard /proc/rtc
256 */
258 p = buf;
260 get_rtc_time(&tm);
262 /*
263 * There is no way to tell if the luser has the RTC set for local
264 * time or for Universal Standard Time (GMT). Probably local though.
265 */
266 p += sprintf(p,
267 "rtc_time\t: %02d:%02d:%02d\n"
268 "rtc_date\t: %04d-%02d-%02d\n"
269 "rtc_epoch\t: %04lu\n"
270 "24hr\t\t: yes\n",
271 tm.tm_hour, tm.tm_min, tm.tm_sec,
272 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
274 return p - buf;
275 }
277 static int rtc_read_proc(char *page, char **start, off_t off,
278 int count, int *eof, void *data)
279 {
280 int len = rtc_get_status(page);
281 if (len <= off+count) *eof = 1;
282 *start = page + off;
283 len -= off;
284 if (len>count) len = count;
285 if (len<0) len = 0;
286 return len;
287 }
289 static void get_rtc_time(struct rtc_time *rtc_tm)
290 {
291 /*
292 * Do we need to wait for the last update to finish?
293 */
295 /*
296 * Only the values that we read from the RTC are set. We leave
297 * tm_wday, tm_yday and tm_isdst untouched. Even though the
298 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
299 * by the RTC when initially set to a non-zero value.
300 */
301 spin_lock_irq(&rtc_lock);
302 rtc->control |= M48T35_RTC_READ;
303 rtc_tm->tm_sec = rtc->sec;
304 rtc_tm->tm_min = rtc->min;
305 rtc_tm->tm_hour = rtc->hour;
306 rtc_tm->tm_mday = rtc->date;
307 rtc_tm->tm_mon = rtc->month;
308 rtc_tm->tm_year = rtc->year;
309 rtc->control &= ~M48T35_RTC_READ;
310 spin_unlock_irq(&rtc_lock);
312 rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
313 rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
314 rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
315 rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
316 rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
317 rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
319 /*
320 * Account for differences between how the RTC uses the values
321 * and how they are defined in a struct rtc_time;
322 */
323 if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
324 rtc_tm->tm_year += 100;
326 rtc_tm->tm_mon--;
327 }