ia64/linux-2.6.18-xen.hg

view drivers/char/ds1286.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 * DS1286 Real Time Clock interface for Linux
3 *
4 * Copyright (C) 1998, 1999, 2000 Ralf Baechle
5 *
6 * Based on code written by Paul Gortmaker.
7 *
8 * This driver allows use of the real time clock (built into nearly all
9 * computers) from user space. It exports the /dev/rtc interface supporting
10 * various ioctl() and also the /proc/rtc pseudo-file for status
11 * information.
12 *
13 * The ioctls can be used to set the interrupt behaviour and generation rate
14 * from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make
15 * use of these timer interrupts, be they interval or alarm based.
16 *
17 * The /dev/rtc interface will block on reads until an interrupt has been
18 * received. If a RTC interrupt has already happened, it will output an
19 * unsigned long and then block. The output value contains the interrupt
20 * status in the low byte and the number of interrupts since the last read
21 * in the remaining high bytes. The /dev/rtc interface can also be used with
22 * the select(2) call.
23 *
24 * This program is free software; you can redistribute it and/or modify it
25 * under the terms of the GNU General Public License as published by the
26 * Free Software Foundation; either version 2 of the License, or (at your
27 * option) any later version.
28 */
29 #include <linux/ds1286.h>
30 #include <linux/types.h>
31 #include <linux/errno.h>
32 #include <linux/miscdevice.h>
33 #include <linux/slab.h>
34 #include <linux/ioport.h>
35 #include <linux/fcntl.h>
36 #include <linux/init.h>
37 #include <linux/poll.h>
38 #include <linux/rtc.h>
39 #include <linux/spinlock.h>
40 #include <linux/bcd.h>
41 #include <linux/proc_fs.h>
43 #include <asm/uaccess.h>
44 #include <asm/system.h>
46 #define DS1286_VERSION "1.0"
48 /*
49 * We sponge a minor off of the misc major. No need slurping
50 * up another valuable major dev number for this. If you add
51 * an ioctl, make sure you don't conflict with SPARC's RTC
52 * ioctls.
53 */
55 static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait);
57 static ssize_t ds1286_read(struct file *file, char *buf,
58 size_t count, loff_t *ppos);
60 static int ds1286_ioctl(struct inode *inode, struct file *file,
61 unsigned int cmd, unsigned long arg);
63 static unsigned int ds1286_poll(struct file *file, poll_table *wait);
65 static void ds1286_get_alm_time (struct rtc_time *alm_tm);
66 static void ds1286_get_time(struct rtc_time *rtc_tm);
67 static int ds1286_set_time(struct rtc_time *rtc_tm);
69 static inline unsigned char ds1286_is_updating(void);
71 static DEFINE_SPINLOCK(ds1286_lock);
73 static int ds1286_read_proc(char *page, char **start, off_t off,
74 int count, int *eof, void *data);
76 /*
77 * Bits in rtc_status. (7 bits of room for future expansion)
78 */
80 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
81 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
83 static unsigned char ds1286_status; /* bitmapped status byte. */
85 static unsigned char days_in_mo[] = {
86 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
87 };
89 /*
90 * Now all the various file operations that we export.
91 */
93 static ssize_t ds1286_read(struct file *file, char *buf,
94 size_t count, loff_t *ppos)
95 {
96 return -EIO;
97 }
99 static int ds1286_ioctl(struct inode *inode, struct file *file,
100 unsigned int cmd, unsigned long arg)
101 {
102 struct rtc_time wtime;
104 switch (cmd) {
105 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
106 {
107 unsigned int flags;
108 unsigned char val;
110 if (!capable(CAP_SYS_TIME))
111 return -EACCES;
113 spin_lock_irqsave(&ds1286_lock, flags);
114 val = rtc_read(RTC_CMD);
115 val |= RTC_TDM;
116 rtc_write(val, RTC_CMD);
117 spin_unlock_irqrestore(&ds1286_lock, flags);
119 return 0;
120 }
121 case RTC_AIE_ON: /* Allow alarm interrupts. */
122 {
123 unsigned int flags;
124 unsigned char val;
126 if (!capable(CAP_SYS_TIME))
127 return -EACCES;
129 spin_lock_irqsave(&ds1286_lock, flags);
130 val = rtc_read(RTC_CMD);
131 val &= ~RTC_TDM;
132 rtc_write(val, RTC_CMD);
133 spin_unlock_irqrestore(&ds1286_lock, flags);
135 return 0;
136 }
137 case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */
138 {
139 unsigned int flags;
140 unsigned char val;
142 if (!capable(CAP_SYS_TIME))
143 return -EACCES;
145 spin_lock_irqsave(&ds1286_lock, flags);
146 val = rtc_read(RTC_CMD);
147 val |= RTC_WAM;
148 rtc_write(val, RTC_CMD);
149 spin_unlock_irqrestore(&ds1286_lock, flags);
151 return 0;
152 }
153 case RTC_WIE_ON: /* Allow watchdog interrupts. */
154 {
155 unsigned int flags;
156 unsigned char val;
158 if (!capable(CAP_SYS_TIME))
159 return -EACCES;
161 spin_lock_irqsave(&ds1286_lock, flags);
162 val = rtc_read(RTC_CMD);
163 val &= ~RTC_WAM;
164 rtc_write(val, RTC_CMD);
165 spin_unlock_irqrestore(&ds1286_lock, flags);
167 return 0;
168 }
169 case RTC_ALM_READ: /* Read the present alarm time */
170 {
171 /*
172 * This returns a struct rtc_time. Reading >= 0xc0
173 * means "don't care" or "match all". Only the tm_hour,
174 * tm_min, and tm_sec values are filled in.
175 */
177 memset(&wtime, 0, sizeof(wtime));
178 ds1286_get_alm_time(&wtime);
179 break;
180 }
181 case RTC_ALM_SET: /* Store a time into the alarm */
182 {
183 /*
184 * This expects a struct rtc_time. Writing 0xff means
185 * "don't care" or "match all". Only the tm_hour,
186 * tm_min and tm_sec are used.
187 */
188 unsigned char hrs, min, sec;
189 struct rtc_time alm_tm;
191 if (!capable(CAP_SYS_TIME))
192 return -EACCES;
194 if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
195 sizeof(struct rtc_time)))
196 return -EFAULT;
198 hrs = alm_tm.tm_hour;
199 min = alm_tm.tm_min;
201 if (hrs >= 24)
202 hrs = 0xff;
204 if (min >= 60)
205 min = 0xff;
207 BIN_TO_BCD(sec);
208 BIN_TO_BCD(min);
209 BIN_TO_BCD(hrs);
211 spin_lock(&ds1286_lock);
212 rtc_write(hrs, RTC_HOURS_ALARM);
213 rtc_write(min, RTC_MINUTES_ALARM);
214 spin_unlock(&ds1286_lock);
216 return 0;
217 }
218 case RTC_RD_TIME: /* Read the time/date from RTC */
219 {
220 memset(&wtime, 0, sizeof(wtime));
221 ds1286_get_time(&wtime);
222 break;
223 }
224 case RTC_SET_TIME: /* Set the RTC */
225 {
226 struct rtc_time rtc_tm;
228 if (!capable(CAP_SYS_TIME))
229 return -EACCES;
231 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
232 sizeof(struct rtc_time)))
233 return -EFAULT;
235 return ds1286_set_time(&rtc_tm);
236 }
237 default:
238 return -EINVAL;
239 }
240 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
241 }
243 /*
244 * We enforce only one user at a time here with the open/close.
245 * Also clear the previous interrupt data on an open, and clean
246 * up things on a close.
247 */
249 static int ds1286_open(struct inode *inode, struct file *file)
250 {
251 spin_lock_irq(&ds1286_lock);
253 if (ds1286_status & RTC_IS_OPEN)
254 goto out_busy;
256 ds1286_status |= RTC_IS_OPEN;
258 spin_unlock_irq(&ds1286_lock);
259 return 0;
261 out_busy:
262 spin_lock_irq(&ds1286_lock);
263 return -EBUSY;
264 }
266 static int ds1286_release(struct inode *inode, struct file *file)
267 {
268 ds1286_status &= ~RTC_IS_OPEN;
270 return 0;
271 }
273 static unsigned int ds1286_poll(struct file *file, poll_table *wait)
274 {
275 poll_wait(file, &ds1286_wait, wait);
277 return 0;
278 }
280 /*
281 * The various file operations we support.
282 */
284 static const struct file_operations ds1286_fops = {
285 .llseek = no_llseek,
286 .read = ds1286_read,
287 .poll = ds1286_poll,
288 .ioctl = ds1286_ioctl,
289 .open = ds1286_open,
290 .release = ds1286_release,
291 };
293 static struct miscdevice ds1286_dev=
294 {
295 .minor = RTC_MINOR,
296 .name = "rtc",
297 .fops = &ds1286_fops,
298 };
300 static int __init ds1286_init(void)
301 {
302 int err;
304 printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION);
306 err = misc_register(&ds1286_dev);
307 if (err)
308 goto out;
310 if (!create_proc_read_entry("driver/rtc", 0, 0, ds1286_read_proc, NULL)) {
311 err = -ENOMEM;
313 goto out_deregister;
314 }
316 return 0;
318 out_deregister:
319 misc_deregister(&ds1286_dev);
321 out:
322 return err;
323 }
325 static void __exit ds1286_exit(void)
326 {
327 remove_proc_entry("driver/rtc", NULL);
328 misc_deregister(&ds1286_dev);
329 }
331 static char *days[] = {
332 "***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
333 };
335 /*
336 * Info exported via "/proc/rtc".
337 */
338 static int ds1286_proc_output(char *buf)
339 {
340 char *p, *s;
341 struct rtc_time tm;
342 unsigned char hundredth, month, cmd, amode;
344 p = buf;
346 ds1286_get_time(&tm);
347 hundredth = rtc_read(RTC_HUNDREDTH_SECOND);
348 BCD_TO_BIN(hundredth);
350 p += sprintf(p,
351 "rtc_time\t: %02d:%02d:%02d.%02d\n"
352 "rtc_date\t: %04d-%02d-%02d\n",
353 tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth,
354 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
356 /*
357 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
358 * match any value for that particular field. Values that are
359 * greater than a valid time, but less than 0xc0 shouldn't appear.
360 */
361 ds1286_get_alm_time(&tm);
362 p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]);
363 if (tm.tm_hour <= 24)
364 p += sprintf(p, "%02d:", tm.tm_hour);
365 else
366 p += sprintf(p, "**:");
368 if (tm.tm_min <= 59)
369 p += sprintf(p, "%02d\n", tm.tm_min);
370 else
371 p += sprintf(p, "**\n");
373 month = rtc_read(RTC_MONTH);
374 p += sprintf(p,
375 "oscillator\t: %s\n"
376 "square_wave\t: %s\n",
377 (month & RTC_EOSC) ? "disabled" : "enabled",
378 (month & RTC_ESQW) ? "disabled" : "enabled");
380 amode = ((rtc_read(RTC_MINUTES_ALARM) & 0x80) >> 5) |
381 ((rtc_read(RTC_HOURS_ALARM) & 0x80) >> 6) |
382 ((rtc_read(RTC_DAY_ALARM) & 0x80) >> 7);
383 if (amode == 7) s = "each minute";
384 else if (amode == 3) s = "minutes match";
385 else if (amode == 1) s = "hours and minutes match";
386 else if (amode == 0) s = "days, hours and minutes match";
387 else s = "invalid";
388 p += sprintf(p, "alarm_mode\t: %s\n", s);
390 cmd = rtc_read(RTC_CMD);
391 p += sprintf(p,
392 "alarm_enable\t: %s\n"
393 "wdog_alarm\t: %s\n"
394 "alarm_mask\t: %s\n"
395 "wdog_alarm_mask\t: %s\n"
396 "interrupt_mode\t: %s\n"
397 "INTB_mode\t: %s_active\n"
398 "interrupt_pins\t: %s\n",
399 (cmd & RTC_TDF) ? "yes" : "no",
400 (cmd & RTC_WAF) ? "yes" : "no",
401 (cmd & RTC_TDM) ? "disabled" : "enabled",
402 (cmd & RTC_WAM) ? "disabled" : "enabled",
403 (cmd & RTC_PU_LVL) ? "pulse" : "level",
404 (cmd & RTC_IBH_LO) ? "low" : "high",
405 (cmd & RTC_IPSW) ? "unswapped" : "swapped");
407 return p - buf;
408 }
410 static int ds1286_read_proc(char *page, char **start, off_t off,
411 int count, int *eof, void *data)
412 {
413 int len = ds1286_proc_output (page);
414 if (len <= off+count) *eof = 1;
415 *start = page + off;
416 len -= off;
417 if (len>count)
418 len = count;
419 if (len<0)
420 len = 0;
422 return len;
423 }
425 /*
426 * Returns true if a clock update is in progress
427 */
428 static inline unsigned char ds1286_is_updating(void)
429 {
430 return rtc_read(RTC_CMD) & RTC_TE;
431 }
434 static void ds1286_get_time(struct rtc_time *rtc_tm)
435 {
436 unsigned char save_control;
437 unsigned int flags;
438 unsigned long uip_watchdog = jiffies;
440 /*
441 * read RTC once any update in progress is done. The update
442 * can take just over 2ms. We wait 10 to 20ms. There is no need to
443 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
444 * If you need to know *exactly* when a second has started, enable
445 * periodic update complete interrupts, (via ioctl) and then
446 * immediately read /dev/rtc which will block until you get the IRQ.
447 * Once the read clears, read the RTC time (again via ioctl). Easy.
448 */
450 if (ds1286_is_updating() != 0)
451 while (jiffies - uip_watchdog < 2*HZ/100)
452 barrier();
454 /*
455 * Only the values that we read from the RTC are set. We leave
456 * tm_wday, tm_yday and tm_isdst untouched. Even though the
457 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
458 * by the RTC when initially set to a non-zero value.
459 */
460 spin_lock_irqsave(&ds1286_lock, flags);
461 save_control = rtc_read(RTC_CMD);
462 rtc_write((save_control|RTC_TE), RTC_CMD);
464 rtc_tm->tm_sec = rtc_read(RTC_SECONDS);
465 rtc_tm->tm_min = rtc_read(RTC_MINUTES);
466 rtc_tm->tm_hour = rtc_read(RTC_HOURS) & 0x3f;
467 rtc_tm->tm_mday = rtc_read(RTC_DATE);
468 rtc_tm->tm_mon = rtc_read(RTC_MONTH) & 0x1f;
469 rtc_tm->tm_year = rtc_read(RTC_YEAR);
471 rtc_write(save_control, RTC_CMD);
472 spin_unlock_irqrestore(&ds1286_lock, flags);
474 BCD_TO_BIN(rtc_tm->tm_sec);
475 BCD_TO_BIN(rtc_tm->tm_min);
476 BCD_TO_BIN(rtc_tm->tm_hour);
477 BCD_TO_BIN(rtc_tm->tm_mday);
478 BCD_TO_BIN(rtc_tm->tm_mon);
479 BCD_TO_BIN(rtc_tm->tm_year);
481 /*
482 * Account for differences between how the RTC uses the values
483 * and how they are defined in a struct rtc_time;
484 */
485 if (rtc_tm->tm_year < 45)
486 rtc_tm->tm_year += 30;
487 if ((rtc_tm->tm_year += 40) < 70)
488 rtc_tm->tm_year += 100;
490 rtc_tm->tm_mon--;
491 }
493 static int ds1286_set_time(struct rtc_time *rtc_tm)
494 {
495 unsigned char mon, day, hrs, min, sec, leap_yr;
496 unsigned char save_control;
497 unsigned int yrs, flags;
500 yrs = rtc_tm->tm_year + 1900;
501 mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
502 day = rtc_tm->tm_mday;
503 hrs = rtc_tm->tm_hour;
504 min = rtc_tm->tm_min;
505 sec = rtc_tm->tm_sec;
507 if (yrs < 1970)
508 return -EINVAL;
510 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
512 if ((mon > 12) || (day == 0))
513 return -EINVAL;
515 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
516 return -EINVAL;
518 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
519 return -EINVAL;
521 if ((yrs -= 1940) > 255) /* They are unsigned */
522 return -EINVAL;
524 if (yrs >= 100)
525 yrs -= 100;
527 BIN_TO_BCD(sec);
528 BIN_TO_BCD(min);
529 BIN_TO_BCD(hrs);
530 BIN_TO_BCD(day);
531 BIN_TO_BCD(mon);
532 BIN_TO_BCD(yrs);
534 spin_lock_irqsave(&ds1286_lock, flags);
535 save_control = rtc_read(RTC_CMD);
536 rtc_write((save_control|RTC_TE), RTC_CMD);
538 rtc_write(yrs, RTC_YEAR);
539 rtc_write(mon, RTC_MONTH);
540 rtc_write(day, RTC_DATE);
541 rtc_write(hrs, RTC_HOURS);
542 rtc_write(min, RTC_MINUTES);
543 rtc_write(sec, RTC_SECONDS);
544 rtc_write(0, RTC_HUNDREDTH_SECOND);
546 rtc_write(save_control, RTC_CMD);
547 spin_unlock_irqrestore(&ds1286_lock, flags);
549 return 0;
550 }
552 static void ds1286_get_alm_time(struct rtc_time *alm_tm)
553 {
554 unsigned char cmd;
555 unsigned int flags;
557 /*
558 * Only the values that we read from the RTC are set. That
559 * means only tm_wday, tm_hour, tm_min.
560 */
561 spin_lock_irqsave(&ds1286_lock, flags);
562 alm_tm->tm_min = rtc_read(RTC_MINUTES_ALARM) & 0x7f;
563 alm_tm->tm_hour = rtc_read(RTC_HOURS_ALARM) & 0x1f;
564 alm_tm->tm_wday = rtc_read(RTC_DAY_ALARM) & 0x07;
565 cmd = rtc_read(RTC_CMD);
566 spin_unlock_irqrestore(&ds1286_lock, flags);
568 BCD_TO_BIN(alm_tm->tm_min);
569 BCD_TO_BIN(alm_tm->tm_hour);
570 alm_tm->tm_sec = 0;
571 }
573 module_init(ds1286_init);
574 module_exit(ds1286_exit);
576 MODULE_AUTHOR("Ralf Baechle");
577 MODULE_LICENSE("GPL");
578 MODULE_ALIAS_MISCDEV(RTC_MINOR);