1 /*
2 * Real Time Clock interface for Linux
3 *
4 * Copyright (C) 1996 Paul Gortmaker
5 *
6 * This driver allows use of the real time clock (built into
7 * nearly all computers) from user space. It exports the /dev/rtc
8 * interface supporting various ioctl() and also the
9 * /proc/driver/rtc pseudo-file for status information.
10 *
11 * The ioctls can be used to set the interrupt behaviour and
12 * generation rate from the RTC via IRQ 8. Then the /dev/rtc
13 * interface can be used to make use of these timer interrupts,
14 * be they interval or alarm based.
15 *
16 * The /dev/rtc interface will block on reads until an interrupt
17 * has been received. If a RTC interrupt has already happened,
18 * it will output an unsigned long and then block. The output value
19 * contains the interrupt status in the low byte and the number of
20 * interrupts since the last read in the remaining high bytes. The
21 * /dev/rtc interface can also be used with the select(2) call.
22 *
23 * This program is free software; you can redistribute it and/or
24 * modify it under the terms of the GNU General Public License
25 * as published by the Free Software Foundation; either version
26 * 2 of the License, or (at your option) any later version.
27 *
28 * Based on other minimal char device drivers, like Alan's
29 * watchdog, Ted's random, etc. etc.
30 *
31 * 1.07 Paul Gortmaker.
32 * 1.08 Miquel van Smoorenburg: disallow certain things on the
33 * DEC Alpha as the CMOS clock is also used for other things.
34 * 1.09 Nikita Schmidt: epoch support and some Alpha cleanup.
35 * 1.09a Pete Zaitcev: Sun SPARC
36 * 1.09b Jeff Garzik: Modularize, init cleanup
37 * 1.09c Jeff Garzik: SMP cleanup
38 * 1.10 Paul Barton-Davis: add support for async I/O
39 * 1.10a Andrea Arcangeli: Alpha updates
40 * 1.10b Andrew Morton: SMP lock fix
41 * 1.10c Cesar Barros: SMP locking fixes and cleanup
42 * 1.10d Paul Gortmaker: delete paranoia check in rtc_exit
43 */
44
45 #define RTC_VERSION "1.10d"
46
47 #define RTC_IO_EXTENT 0x10 /* Only really two ports, but... */
48
49 /*
50 * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
51 * interrupts disabled. Due to the index-port/data-port (0x70/0x71)
52 * design of the RTC, we don't want two different things trying to
53 * get to it at once. (e.g. the periodic 11 min sync from time.c vs.
54 * this driver.)
55 */
56
57 #include <linux/config.h>
58 #include <linux/module.h>
59 #include <linux/kernel.h>
60 #include <linux/types.h>
61 #include <linux/miscdevice.h>
62 #include <linux/ioport.h>
63 #include <linux/fcntl.h>
64 #include <linux/mc146818rtc.h>
65 #include <linux/init.h>
66 #include <linux/poll.h>
67 #include <linux/proc_fs.h>
68 #include <linux/spinlock.h>
69
70 #include <asm/io.h>
71 #include <asm/uaccess.h>
72 #include <asm/system.h>
73
74 #ifdef __sparc__
75 #include <asm/ebus.h>
76
77 static unsigned long rtc_port;
78 static int rtc_irq;
79 #endif
80
81 /*
82 * We sponge a minor off of the misc major. No need slurping
83 * up another valuable major dev number for this. If you add
84 * an ioctl, make sure you don't conflict with SPARC's RTC
85 * ioctls.
86 */
87
88 static struct fasync_struct *rtc_async_queue;
89
90 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
91
92 static struct timer_list rtc_irq_timer;
93
94 static loff_t rtc_llseek(struct file *file, loff_t offset, int origin);
95
96 static ssize_t rtc_read(struct file *file, char *buf,
97 size_t count, loff_t *ppos);
98
99 static int rtc_ioctl(struct inode *inode, struct file *file,
100 unsigned int cmd, unsigned long arg);
101
102 #if RTC_IRQ
103 static unsigned int rtc_poll(struct file *file, poll_table *wait);
104 #endif
105
106 static void get_rtc_time (struct rtc_time *rtc_tm);
107 static void get_rtc_alm_time (struct rtc_time *alm_tm);
108 #if RTC_IRQ
109 static void rtc_dropped_irq(unsigned long data);
110
111 static void set_rtc_irq_bit(unsigned char bit);
112 static void mask_rtc_irq_bit(unsigned char bit);
113 #endif
114
115 static inline unsigned char rtc_is_updating(void);
116
117 static int rtc_read_proc(char *page, char **start, off_t off,
118 int count, int *eof, void *data);
119
120 /*
121 * Bits in rtc_status. (6 bits of room for future expansion)
122 */
123
124 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
125 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
126
127 /*
128 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
129 * protected by the big kernel lock. However, ioctl can still disable the timer
130 * in rtc_status and then with del_timer after the interrupt has read
131 * rtc_status but before mod_timer is called, which would then reenable the
132 * timer (but you would need to have an awful timing before you'd trip on it)
133 */
134 static unsigned long rtc_status = 0; /* bitmapped status byte. */
135 static unsigned long rtc_freq = 0; /* Current periodic IRQ rate */
136 static unsigned long rtc_irq_data = 0; /* our output to the world */
137
138 /*
139 * If this driver ever becomes modularised, it will be really nice
140 * to make the epoch retain its value across module reload...
141 */
142
143 static unsigned long epoch = 1900; /* year corresponding to 0x00 */
144
145 static const unsigned char days_in_mo[] =
146 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
147
148 #if RTC_IRQ
149 /*
150 * A very tiny interrupt handler. It runs with SA_INTERRUPT set,
151 * but there is possibility of conflicting with the set_rtc_mmss()
152 * call (the rtc irq and the timer irq can easily run at the same
153 * time in two different CPUs). So we need to serializes
154 * accesses to the chip with the rtc_lock spinlock that each
155 * architecture should implement in the timer code.
156 * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
157 */
158
159 static void rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
160 {
161 /*
162 * Can be an alarm interrupt, update complete interrupt,
163 * or a periodic interrupt. We store the status in the
164 * low byte and the number of interrupts received since
165 * the last read in the remainder of rtc_irq_data.
166 */
167
168 spin_lock (&rtc_lock);
169 rtc_irq_data += 0x100;
170 rtc_irq_data &= ~0xff;
171 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
172
173 if (rtc_status & RTC_TIMER_ON)
174 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
175
176 spin_unlock (&rtc_lock);
177
178 /* Now do the rest of the actions */
179 wake_up_interruptible(&rtc_wait);
180
181 kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
182 }
183 #endif
184
185 /*
186 * Now all the various file operations that we export.
187 */
188
189 static loff_t rtc_llseek(struct file *file, loff_t offset, int origin)
190 {
191 return -ESPIPE;
192 }
193
194 static ssize_t rtc_read(struct file *file, char *buf,
195 size_t count, loff_t *ppos)
196 {
197 #if !RTC_IRQ
198 return -EIO;
199 #else
200 DECLARE_WAITQUEUE(wait, current);
201 unsigned long data;
202 ssize_t retval;
203
204 if (count < sizeof(unsigned long))
205 return -EINVAL;
206
207 add_wait_queue(&rtc_wait, &wait);
208
209 current->state = TASK_INTERRUPTIBLE;
210
211 do {
212 /* First make it right. Then make it fast. Putting this whole
213 * block within the parentheses of a while would be too
214 * confusing. And no, xchg() is not the answer. */
215 spin_lock_irq (&rtc_lock);
216 data = rtc_irq_data;
217 rtc_irq_data = 0;
218 spin_unlock_irq (&rtc_lock);
219
220 if (data != 0)
221 break;
222
223 if (file->f_flags & O_NONBLOCK) {
224 retval = -EAGAIN;
225 goto out;
226 }
227 if (signal_pending(current)) {
228 retval = -ERESTARTSYS;
229 goto out;
230 }
231 schedule();
232 } while (1);
233
234 retval = put_user(data, (unsigned long *)buf);
235 if (!retval)
236 retval = sizeof(unsigned long);
237 out:
238 current->state = TASK_RUNNING;
239 remove_wait_queue(&rtc_wait, &wait);
240
241 return retval;
242 #endif
243 }
244
245 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
246 unsigned long arg)
247 {
248 struct rtc_time wtime;
249
250 switch (cmd) {
251 #if RTC_IRQ
252 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
253 {
254 mask_rtc_irq_bit(RTC_AIE);
255 return 0;
256 }
257 case RTC_AIE_ON: /* Allow alarm interrupts. */
258 {
259 set_rtc_irq_bit(RTC_AIE);
260 return 0;
261 }
262 case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
263 {
264 mask_rtc_irq_bit(RTC_PIE);
265 if (rtc_status & RTC_TIMER_ON) {
266 spin_lock_irq (&rtc_lock);
267 rtc_status &= ~RTC_TIMER_ON;
268 del_timer(&rtc_irq_timer);
269 spin_unlock_irq (&rtc_lock);
270 }
271 return 0;
272 }
273 case RTC_PIE_ON: /* Allow periodic ints */
274 {
275
276 /*
277 * We don't really want Joe User enabling more
278 * than 64Hz of interrupts on a multi-user machine.
279 */
280 if ((rtc_freq > 64) && (!capable(CAP_SYS_RESOURCE)))
281 return -EACCES;
282
283 if (!(rtc_status & RTC_TIMER_ON)) {
284 spin_lock_irq (&rtc_lock);
285 rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
286 add_timer(&rtc_irq_timer);
287 rtc_status |= RTC_TIMER_ON;
288 spin_unlock_irq (&rtc_lock);
289 }
290 set_rtc_irq_bit(RTC_PIE);
291 return 0;
292 }
293 case RTC_UIE_OFF: /* Mask ints from RTC updates. */
294 {
295 mask_rtc_irq_bit(RTC_UIE);
296 return 0;
297 }
298 case RTC_UIE_ON: /* Allow ints for RTC updates. */
299 {
300 set_rtc_irq_bit(RTC_UIE);
301 return 0;
302 }
303 #endif
304 case RTC_ALM_READ: /* Read the present alarm time */
305 {
306 /*
307 * This returns a struct rtc_time. Reading >= 0xc0
308 * means "don't care" or "match all". Only the tm_hour,
309 * tm_min, and tm_sec values are filled in.
310 */
311
312 get_rtc_alm_time(&wtime);
313 break;
314 }
315 case RTC_ALM_SET: /* Store a time into the alarm */
316 {
317 /*
318 * This expects a struct rtc_time. Writing 0xff means
319 * "don't care" or "match all". Only the tm_hour,
320 * tm_min and tm_sec are used.
321 */
322 unsigned char hrs, min, sec;
323 struct rtc_time alm_tm;
324
325 if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
326 sizeof(struct rtc_time)))
327 return -EFAULT;
328
329 hrs = alm_tm.tm_hour;
330 min = alm_tm.tm_min;
331 sec = alm_tm.tm_sec;
332
333 if (hrs >= 24)
334 hrs = 0xff;
335
336 if (min >= 60)
337 min = 0xff;
338
339 if (sec >= 60)
340 sec = 0xff;
341
342 spin_lock_irq(&rtc_lock);
343 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
344 RTC_ALWAYS_BCD)
345 {
346 BIN_TO_BCD(sec);
347 BIN_TO_BCD(min);
348 BIN_TO_BCD(hrs);
349 }
350 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
351 CMOS_WRITE(min, RTC_MINUTES_ALARM);
352 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
353 spin_unlock_irq(&rtc_lock);
354
355 return 0;
356 }
357 case RTC_RD_TIME: /* Read the time/date from RTC */
358 {
359 get_rtc_time(&wtime);
360 break;
361 }
362 case RTC_SET_TIME: /* Set the RTC */
363 {
364 struct rtc_time rtc_tm;
365 unsigned char mon, day, hrs, min, sec, leap_yr;
366 unsigned char save_control, save_freq_select;
367 unsigned int yrs;
368
369 if (!capable(CAP_SYS_TIME))
370 return -EACCES;
371
372 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
373 sizeof(struct rtc_time)))
374 return -EFAULT;
375
376 yrs = rtc_tm.tm_year + 1900;
377 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
378 day = rtc_tm.tm_mday;
379 hrs = rtc_tm.tm_hour;
380 min = rtc_tm.tm_min;
381 sec = rtc_tm.tm_sec;
382
383 if (yrs < 1970)
384 return -EINVAL;
385
386 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
387
388 if ((mon > 12) || (day == 0))
389 return -EINVAL;
390
391 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
392 return -EINVAL;
393
394 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
395 return -EINVAL;
396
397 if ((yrs -= epoch) > 255) /* They are unsigned */
398 return -EINVAL;
399
400 spin_lock_irq(&rtc_lock);
401 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
402 || RTC_ALWAYS_BCD) {
403 if (yrs > 169) {
404 spin_unlock_irq(&rtc_lock);
405 return -EINVAL;
406 }
407 if (yrs >= 100)
408 yrs -= 100;
409
410 BIN_TO_BCD(sec);
411 BIN_TO_BCD(min);
412 BIN_TO_BCD(hrs);
413 BIN_TO_BCD(day);
414 BIN_TO_BCD(mon);
415 BIN_TO_BCD(yrs);
416 }
417
418 save_control = CMOS_READ(RTC_CONTROL);
419 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
420 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
421 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
422
423 CMOS_WRITE(yrs, RTC_YEAR);
424 CMOS_WRITE(mon, RTC_MONTH);
425 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
426 CMOS_WRITE(hrs, RTC_HOURS);
427 CMOS_WRITE(min, RTC_MINUTES);
428 CMOS_WRITE(sec, RTC_SECONDS);
429
430 CMOS_WRITE(save_control, RTC_CONTROL);
431 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
432
433 spin_unlock_irq(&rtc_lock);
434 return 0;
435 }
436 #if RTC_IRQ
437 case RTC_IRQP_READ: /* Read the periodic IRQ rate. */
438 {
439 return put_user(rtc_freq, (unsigned long *)arg);
440 }
441 case RTC_IRQP_SET: /* Set periodic IRQ rate. */
442 {
443 int tmp = 0;
444 unsigned char val;
445
446 /*
447 * The max we can do is 8192Hz.
448 */
449 if ((arg < 2) || (arg > 8192))
450 return -EINVAL;
451 /*
452 * We don't really want Joe User generating more
453 * than 64Hz of interrupts on a multi-user machine.
454 */
455 if ((arg > 64) && (!capable(CAP_SYS_RESOURCE)))
456 return -EACCES;
457
458 while (arg > (1<<tmp))
459 tmp++;
460
461 /*
462 * Check that the input was really a power of 2.
463 */
464 if (arg != (1<<tmp))
465 return -EINVAL;
466
467 spin_lock_irq(&rtc_lock);
468 rtc_freq = arg;
469
470 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
471 val |= (16 - tmp);
472 CMOS_WRITE(val, RTC_FREQ_SELECT);
473 spin_unlock_irq(&rtc_lock);
474 return 0;
475 }
476 #elif !defined(CONFIG_DECSTATION)
477 case RTC_EPOCH_READ: /* Read the epoch. */
478 {
479 return put_user (epoch, (unsigned long *)arg);
480 }
481 case RTC_EPOCH_SET: /* Set the epoch. */
482 {
483 /*
484 * There were no RTC clocks before 1900.
485 */
486 if (arg < 1900)
487 return -EINVAL;
488
489 if (!capable(CAP_SYS_TIME))
490 return -EACCES;
491
492 epoch = arg;
493 return 0;
494 }
495 #endif
496 default:
497 return -EINVAL;
498 }
499 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
500 }
501
502 /*
503 * We enforce only one user at a time here with the open/close.
504 * Also clear the previous interrupt data on an open, and clean
505 * up things on a close.
506 */
507
508 /* We use rtc_lock to protect against concurrent opens. So the BKL is not
509 * needed here. Or anywhere else in this driver. */
510 static int rtc_open(struct inode *inode, struct file *file)
511 {
512 spin_lock_irq (&rtc_lock);
513
514 if(rtc_status & RTC_IS_OPEN)
515 goto out_busy;
516
517 rtc_status |= RTC_IS_OPEN;
518
519 rtc_irq_data = 0;
520 spin_unlock_irq (&rtc_lock);
521 return 0;
522
523 out_busy:
524 spin_unlock_irq (&rtc_lock);
525 return -EBUSY;
526 }
527
528 static int rtc_fasync (int fd, struct file *filp, int on)
529
530 {
531 return fasync_helper (fd, filp, on, &rtc_async_queue);
532 }
533
534 static int rtc_release(struct inode *inode, struct file *file)
535 {
536 #if RTC_IRQ
537 /*
538 * Turn off all interrupts once the device is no longer
539 * in use, and clear the data.
540 */
541
542 unsigned char tmp;
543
544 spin_lock_irq(&rtc_lock);
545 tmp = CMOS_READ(RTC_CONTROL);
546 tmp &= ~RTC_PIE;
547 tmp &= ~RTC_AIE;
548 tmp &= ~RTC_UIE;
549 CMOS_WRITE(tmp, RTC_CONTROL);
550 CMOS_READ(RTC_INTR_FLAGS);
551
552 if (rtc_status & RTC_TIMER_ON) {
553 rtc_status &= ~RTC_TIMER_ON;
554 del_timer(&rtc_irq_timer);
555 }
556 spin_unlock_irq(&rtc_lock);
557
558 if (file->f_flags & FASYNC) {
559 rtc_fasync (-1, file, 0);
560 }
561 #endif
562
563 spin_lock_irq (&rtc_lock);
564 rtc_irq_data = 0;
565 spin_unlock_irq (&rtc_lock);
566
567 /* No need for locking -- nobody else can do anything until this rmw is
568 * committed, and no timer is running. */
569 rtc_status &= ~RTC_IS_OPEN;
570 return 0;
571 }
572
573 #if RTC_IRQ
574 /* Called without the kernel lock - fine */
575 static unsigned int rtc_poll(struct file *file, poll_table *wait)
576 {
577 unsigned long l;
578
579 poll_wait(file, &rtc_wait, wait);
580
581 spin_lock_irq (&rtc_lock);
582 l = rtc_irq_data;
583 spin_unlock_irq (&rtc_lock);
584
585 if (l != 0)
586 return POLLIN | POLLRDNORM;
587 return 0;
588 }
589 #endif
590
591 /*
592 * The various file operations we support.
593 */
594
595 static struct file_operations rtc_fops = {
596 owner: THIS_MODULE,
597 llseek: rtc_llseek,
598 read: rtc_read,
599 #if RTC_IRQ
600 poll: rtc_poll,
601 #endif
602 ioctl: rtc_ioctl,
603 open: rtc_open,
604 release: rtc_release,
605 fasync: rtc_fasync,
606 };
607
608 static struct miscdevice rtc_dev=
609 {
610 RTC_MINOR,
611 "rtc",
612 &rtc_fops
613 };
614
615 static int __init rtc_init(void)
616 {
617 #if defined(__alpha__) || defined(__mips__)
618 unsigned int year, ctrl;
619 unsigned long uip_watchdog;
620 char *guess = NULL;
621 #endif
622 #ifdef __sparc__
623 struct linux_ebus *ebus;
624 struct linux_ebus_device *edev;
625 #endif
626
627 #ifdef __sparc__
628 for_each_ebus(ebus) {
629 for_each_ebusdev(edev, ebus) {
630 if(strcmp(edev->prom_name, "rtc") == 0) {
631 goto found;
632 }
633 }
634 }
635 printk(KERN_ERR "rtc_init: no PC rtc found\n");
636 return -EIO;
637
638 found:
639 rtc_port = edev->resource[0].start;
640 rtc_irq = edev->irqs[0];
641 /*
642 * XXX Interrupt pin #7 in Espresso is shared between RTC and
643 * PCI Slot 2 INTA# (and some INTx# in Slot 1). SA_INTERRUPT here
644 * is asking for trouble with add-on boards. Change to SA_SHIRQ.
645 */
646 if(request_irq(rtc_irq, rtc_interrupt, SA_INTERRUPT, "rtc", (void *)&rtc_port)) {
647 /*
648 * Standard way for sparc to print irq's is to use
649 * __irq_itoa(). I think for EBus it's ok to use %d.
650 */
651 printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
652 return -EIO;
653 }
654 #else
655 if (check_region (RTC_PORT (0), RTC_IO_EXTENT))
656 {
657 printk(KERN_ERR "rtc: I/O port %d is not free.\n", RTC_PORT (0));
658 return -EIO;
659 }
660
661 #if RTC_IRQ
662 if(request_irq(RTC_IRQ, rtc_interrupt, SA_INTERRUPT, "rtc", NULL))
663 {
664 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
665 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
666 return -EIO;
667 }
668 #endif
669
670 request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
671 #endif /* __sparc__ vs. others */
672
673 misc_register(&rtc_dev);
674 create_proc_read_entry ("driver/rtc", 0, 0, rtc_read_proc, NULL);
675
676 #if defined(__alpha__) || defined(__mips__)
677 rtc_freq = HZ;
678
679 /* Each operating system on an Alpha uses its own epoch.
680 Let's try to guess which one we are using now. */
681
682 uip_watchdog = jiffies;
683 if (rtc_is_updating() != 0)
684 while (jiffies - uip_watchdog < 2*HZ/100)
685 barrier();
686
687 spin_lock_irq(&rtc_lock);
688 year = CMOS_READ(RTC_YEAR);
689 ctrl = CMOS_READ(RTC_CONTROL);
690 spin_unlock_irq(&rtc_lock);
691
692 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
693 BCD_TO_BIN(year); /* This should never happen... */
694
695 if (year >= 20 && year < 48) {
696 epoch = 1980;
697 guess = "ARC console";
698 } else if (year >= 48 && year < 70) {
699 epoch = 1952;
700 guess = "Digital UNIX";
701 } else if (year >= 70 && year < 100) {
702 epoch = 1928;
703 guess = "Digital DECstation";
704 }
705 if (guess)
706 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", guess, epoch);
707 #endif
708 #if RTC_IRQ
709 init_timer(&rtc_irq_timer);
710 rtc_irq_timer.function = rtc_dropped_irq;
711 spin_lock_irq(&rtc_lock);
712 /* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
713 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), RTC_FREQ_SELECT);
714 spin_unlock_irq(&rtc_lock);
715 rtc_freq = 1024;
716 #endif
717
718 printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
719
720 return 0;
721 }
722
723 static void __exit rtc_exit (void)
724 {
725 remove_proc_entry ("driver/rtc", NULL);
726 misc_deregister(&rtc_dev);
727
728 #ifdef __sparc__
729 free_irq (rtc_irq, &rtc_port);
730 #else
731 release_region (RTC_PORT (0), RTC_IO_EXTENT);
732 #if RTC_IRQ
733 free_irq (RTC_IRQ, NULL);
734 #endif
735 #endif /* __sparc__ */
736 }
737
738 module_init(rtc_init);
739 module_exit(rtc_exit);
740 EXPORT_NO_SYMBOLS;
741
742 #if RTC_IRQ
743 /*
744 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
745 * (usually during an IDE disk interrupt, with IRQ unmasking off)
746 * Since the interrupt handler doesn't get called, the IRQ status
747 * byte doesn't get read, and the RTC stops generating interrupts.
748 * A timer is set, and will call this function if/when that happens.
749 * To get it out of this stalled state, we just read the status.
750 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
751 * (You *really* shouldn't be trying to use a non-realtime system
752 * for something that requires a steady > 1KHz signal anyways.)
753 */
754
755 static void rtc_dropped_irq(unsigned long data)
756 {
757 unsigned long freq;
758
759 spin_lock_irq (&rtc_lock);
760
761 /* Just in case someone disabled the timer from behind our back... */
762 if (rtc_status & RTC_TIMER_ON)
763 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
764
765 rtc_irq_data += ((rtc_freq/HZ)<<8);
766 rtc_irq_data &= ~0xff;
767 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */
768
769 freq = rtc_freq;
770
771 spin_unlock_irq(&rtc_lock);
772
773 printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", freq);
774
775 /* Now we have new data */
776 wake_up_interruptible(&rtc_wait);
777
778 kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
779 }
780 #endif
781
782 /*
783 * Info exported via "/proc/driver/rtc".
784 */
785
786 static int rtc_proc_output (char *buf)
787 {
788 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
789 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
790 char *p;
791 struct rtc_time tm;
792 unsigned char batt, ctrl;
793 unsigned long freq;
794
795 spin_lock_irq(&rtc_lock);
796 batt = CMOS_READ(RTC_VALID) & RTC_VRT;
797 ctrl = CMOS_READ(RTC_CONTROL);
798 freq = rtc_freq;
799 spin_unlock_irq(&rtc_lock);
800
801 p = buf;
802
803 get_rtc_time(&tm);
804
805 /*
806 * There is no way to tell if the luser has the RTC set for local
807 * time or for Universal Standard Time (GMT). Probably local though.
808 */
809 p += sprintf(p,
810 "rtc_time\t: %02d:%02d:%02d\n"
811 "rtc_date\t: %04d-%02d-%02d\n"
812 "rtc_epoch\t: %04lu\n",
813 tm.tm_hour, tm.tm_min, tm.tm_sec,
814 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
815
816 get_rtc_alm_time(&tm);
817
818 /*
819 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
820 * match any value for that particular field. Values that are
821 * greater than a valid time, but less than 0xc0 shouldn't appear.
822 */
823 p += sprintf(p, "alarm\t\t: ");
824 if (tm.tm_hour <= 24)
825 p += sprintf(p, "%02d:", tm.tm_hour);
826 else
827 p += sprintf(p, "**:");
828
829 if (tm.tm_min <= 59)
830 p += sprintf(p, "%02d:", tm.tm_min);
831 else
832 p += sprintf(p, "**:");
833
834 if (tm.tm_sec <= 59)
835 p += sprintf(p, "%02d\n", tm.tm_sec);
836 else
837 p += sprintf(p, "**\n");
838
839 p += sprintf(p,
840 "DST_enable\t: %s\n"
841 "BCD\t\t: %s\n"
842 "24hr\t\t: %s\n"
843 "square_wave\t: %s\n"
844 "alarm_IRQ\t: %s\n"
845 "update_IRQ\t: %s\n"
846 "periodic_IRQ\t: %s\n"
847 "periodic_freq\t: %ld\n"
848 "batt_status\t: %s\n",
849 YN(RTC_DST_EN),
850 NY(RTC_DM_BINARY),
851 YN(RTC_24H),
852 YN(RTC_SQWE),
853 YN(RTC_AIE),
854 YN(RTC_UIE),
855 YN(RTC_PIE),
856 freq,
857 batt ? "okay" : "dead");
858
859 return p - buf;
860 #undef YN
861 #undef NY
862 }
863
864 static int rtc_read_proc(char *page, char **start, off_t off,
865 int count, int *eof, void *data)
866 {
867 int len = rtc_proc_output (page);
868 if (len <= off+count) *eof = 1;
869 *start = page + off;
870 len -= off;
871 if (len>count) len = count;
872 if (len<0) len = 0;
873 return len;
874 }
875
876 /*
877 * Returns true if a clock update is in progress
878 */
879 /* FIXME shouldn't this be above rtc_init to make it fully inlined? */
880 static inline unsigned char rtc_is_updating(void)
881 {
882 unsigned char uip;
883
884 spin_lock_irq(&rtc_lock);
885 uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
886 spin_unlock_irq(&rtc_lock);
887 return uip;
888 }
889
890 static void get_rtc_time(struct rtc_time *rtc_tm)
891 {
892 unsigned long uip_watchdog = jiffies;
893 unsigned char ctrl;
894
895 /*
896 * read RTC once any update in progress is done. The update
897 * can take just over 2ms. We wait 10 to 20ms. There is no need to
898 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
899 * If you need to know *exactly* when a second has started, enable
900 * periodic update complete interrupts, (via ioctl) and then
901 * immediately read /dev/rtc which will block until you get the IRQ.
902 * Once the read clears, read the RTC time (again via ioctl). Easy.
903 */
904
905 if (rtc_is_updating() != 0)
906 while (jiffies - uip_watchdog < 2*HZ/100)
907 barrier();
908
909 /*
910 * Only the values that we read from the RTC are set. We leave
911 * tm_wday, tm_yday and tm_isdst untouched. Even though the
912 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
913 * by the RTC when initially set to a non-zero value.
914 */
915 spin_lock_irq(&rtc_lock);
916 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
917 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
918 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
919 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
920 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
921 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
922 ctrl = CMOS_READ(RTC_CONTROL);
923 spin_unlock_irq(&rtc_lock);
924
925 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
926 {
927 BCD_TO_BIN(rtc_tm->tm_sec);
928 BCD_TO_BIN(rtc_tm->tm_min);
929 BCD_TO_BIN(rtc_tm->tm_hour);
930 BCD_TO_BIN(rtc_tm->tm_mday);
931 BCD_TO_BIN(rtc_tm->tm_mon);
932 BCD_TO_BIN(rtc_tm->tm_year);
933 }
934
935 /*
936 * Account for differences between how the RTC uses the values
937 * and how they are defined in a struct rtc_time;
938 */
939 if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
940 rtc_tm->tm_year += 100;
941
942 rtc_tm->tm_mon--;
943 }
944
945 static void get_rtc_alm_time(struct rtc_time *alm_tm)
946 {
947 unsigned char ctrl;
948
949 /*
950 * Only the values that we read from the RTC are set. That
951 * means only tm_hour, tm_min, and tm_sec.
952 */
953 spin_lock_irq(&rtc_lock);
954 alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
955 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
956 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
957 ctrl = CMOS_READ(RTC_CONTROL);
958 spin_unlock_irq(&rtc_lock);
959
960 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
961 {
962 BCD_TO_BIN(alm_tm->tm_sec);
963 BCD_TO_BIN(alm_tm->tm_min);
964 BCD_TO_BIN(alm_tm->tm_hour);
965 }
966 }
967
968 #if RTC_IRQ
969 /*
970 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
971 * Rumour has it that if you frob the interrupt enable/disable
972 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
973 * ensure you actually start getting interrupts. Probably for
974 * compatibility with older/broken chipset RTC implementations.
975 * We also clear out any old irq data after an ioctl() that
976 * meddles with the interrupt enable/disable bits.
977 */
978
979 static void mask_rtc_irq_bit(unsigned char bit)
980 {
981 unsigned char val;
982
983 spin_lock_irq(&rtc_lock);
984 val = CMOS_READ(RTC_CONTROL);
985 val &= ~bit;
986 CMOS_WRITE(val, RTC_CONTROL);
987 CMOS_READ(RTC_INTR_FLAGS);
988
989 rtc_irq_data = 0;
990 spin_unlock_irq(&rtc_lock);
991 }
992
993 static void set_rtc_irq_bit(unsigned char bit)
994 {
995 unsigned char val;
996
997 spin_lock_irq(&rtc_lock);
998 val = CMOS_READ(RTC_CONTROL);
999 val |= bit;
1000 CMOS_WRITE(val, RTC_CONTROL);
1001 CMOS_READ(RTC_INTR_FLAGS);
1002
1003 rtc_irq_data = 0;
1004 spin_unlock_irq(&rtc_lock);
1005 }
1006 #endif
1007
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