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 * 1.10e Maciej W. Rozycki: Handle DECstation's year weirdness.
44 * 1.10f Maciej W. Rozycki: Handle memory-mapped chips properly.
45 */
46
47 #define RTC_VERSION "1.10f"
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 #include <linux/sysctl.h>
70
71 #include <asm/io.h>
72 #include <asm/uaccess.h>
73 #include <asm/system.h>
74
75 #ifdef __sparc__
76 #include <linux/pci.h>
77 #include <asm/ebus.h>
78 #ifdef __sparc_v9__
79 #include <asm/isa.h>
80 #endif
81
82 static unsigned long rtc_port;
83 static int rtc_irq = PCI_IRQ_NONE;
84 #endif
85
86 #if RTC_IRQ
87 static int rtc_has_irq = 1;
88 #endif
89
90 /*
91 * We sponge a minor off of the misc major. No need slurping
92 * up another valuable major dev number for this. If you add
93 * an ioctl, make sure you don't conflict with SPARC's RTC
94 * ioctls.
95 */
96
97 static struct fasync_struct *rtc_async_queue;
98
99 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
100
101 #if RTC_IRQ
102 static struct timer_list rtc_irq_timer;
103 #endif
104
105 static ssize_t rtc_read(struct file *file, char *buf,
106 size_t count, loff_t *ppos);
107
108 static int rtc_ioctl(struct inode *inode, struct file *file,
109 unsigned int cmd, unsigned long arg);
110
111 #if RTC_IRQ
112 static unsigned int rtc_poll(struct file *file, poll_table *wait);
113 #endif
114
115 static void get_rtc_time (struct rtc_time *rtc_tm);
116 static void get_rtc_alm_time (struct rtc_time *alm_tm);
117 #if RTC_IRQ
118 static void rtc_dropped_irq(unsigned long data);
119
120 static void set_rtc_irq_bit(unsigned char bit);
121 static void mask_rtc_irq_bit(unsigned char bit);
122 #endif
123
124 static inline unsigned char rtc_is_updating(void);
125
126 static int rtc_read_proc(char *page, char **start, off_t off,
127 int count, int *eof, void *data);
128
129 /*
130 * Bits in rtc_status. (6 bits of room for future expansion)
131 */
132
133 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
134 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
135
136 /*
137 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
138 * protected by the big kernel lock. However, ioctl can still disable the timer
139 * in rtc_status and then with del_timer after the interrupt has read
140 * rtc_status but before mod_timer is called, which would then reenable the
141 * timer (but you would need to have an awful timing before you'd trip on it)
142 */
143 static unsigned long rtc_status = 0; /* bitmapped status byte. */
144 static unsigned long rtc_freq = 0; /* Current periodic IRQ rate */
145 static unsigned long rtc_irq_data = 0; /* our output to the world */
146 static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */
147
148 /*
149 * If this driver ever becomes modularised, it will be really nice
150 * to make the epoch retain its value across module reload...
151 */
152
153 static unsigned long epoch = 1900; /* year corresponding to 0x00 */
154
155 static const unsigned char days_in_mo[] =
156 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
157
158 #if RTC_IRQ
159 /*
160 * A very tiny interrupt handler. It runs with SA_INTERRUPT set,
161 * but there is possibility of conflicting with the set_rtc_mmss()
162 * call (the rtc irq and the timer irq can easily run at the same
163 * time in two different CPUs). So we need to serializes
164 * accesses to the chip with the rtc_lock spinlock that each
165 * architecture should implement in the timer code.
166 * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
167 */
168
rtc_interrupt(int irq,void * dev_id,struct pt_regs * regs)169 static void rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
170 {
171 /*
172 * Can be an alarm interrupt, update complete interrupt,
173 * or a periodic interrupt. We store the status in the
174 * low byte and the number of interrupts received since
175 * the last read in the remainder of rtc_irq_data.
176 */
177
178 spin_lock (&rtc_lock);
179 rtc_irq_data += 0x100;
180 rtc_irq_data &= ~0xff;
181 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
182
183 if (rtc_status & RTC_TIMER_ON)
184 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
185
186 spin_unlock (&rtc_lock);
187
188 /* Now do the rest of the actions */
189 wake_up_interruptible(&rtc_wait);
190
191 kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
192 }
193 #endif
194
195 /*
196 * sysctl-tuning infrastructure.
197 */
198 static ctl_table rtc_table[] = {
199 { 1, "max-user-freq", &rtc_max_user_freq, sizeof(int), 0644, NULL,
200 &proc_dointvec, NULL, },
201 { 0, }
202 };
203
204 static ctl_table rtc_root[] = {
205 { 1, "rtc", NULL, 0, 0555, rtc_table, },
206 { 0, }
207 };
208
209 static ctl_table dev_root[] = {
210 { CTL_DEV, "dev", NULL, 0, 0555, rtc_root, },
211 { 0, }
212 };
213
214 static struct ctl_table_header *sysctl_header;
215
init_sysctl(void)216 static int __init init_sysctl(void)
217 {
218 sysctl_header = register_sysctl_table(dev_root, 0);
219 return 0;
220 }
221
cleanup_sysctl(void)222 static void __exit cleanup_sysctl(void)
223 {
224 unregister_sysctl_table(sysctl_header);
225 }
226
227 /*
228 * Now all the various file operations that we export.
229 */
230
rtc_read(struct file * file,char * buf,size_t count,loff_t * ppos)231 static ssize_t rtc_read(struct file *file, char *buf,
232 size_t count, loff_t *ppos)
233 {
234 #if !RTC_IRQ
235 return -EIO;
236 #else
237 DECLARE_WAITQUEUE(wait, current);
238 unsigned long data;
239 ssize_t retval;
240
241 if (rtc_has_irq == 0)
242 return -EIO;
243
244 /*
245 * Historically this function used to assume that sizeof(unsigned long)
246 * is the same in userspace and kernelspace. This lead to problems
247 * for configurations with multiple ABIs such a the MIPS o32 and 64
248 * ABIs supported on the same kernel. So now we support read of both
249 * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
250 * userspace ABI.
251 */
252 if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
253 return -EINVAL;
254
255 add_wait_queue(&rtc_wait, &wait);
256
257 do {
258 __set_current_state(TASK_INTERRUPTIBLE);
259
260 /* First make it right. Then make it fast. Putting this whole
261 * block within the parentheses of a while would be too
262 * confusing. And no, xchg() is not the answer. */
263 spin_lock_irq (&rtc_lock);
264 data = rtc_irq_data;
265 rtc_irq_data = 0;
266 spin_unlock_irq (&rtc_lock);
267
268 if (data != 0)
269 break;
270
271 if (file->f_flags & O_NONBLOCK) {
272 retval = -EAGAIN;
273 goto out;
274 }
275 if (signal_pending(current)) {
276 retval = -ERESTARTSYS;
277 goto out;
278 }
279 schedule();
280 } while (1);
281
282 if (count == sizeof(unsigned int))
283 retval = put_user(data, (unsigned int *)buf);
284 else
285 retval = put_user(data, (unsigned long *)buf);
286 if (!retval)
287 retval = count;
288 out:
289 current->state = TASK_RUNNING;
290 remove_wait_queue(&rtc_wait, &wait);
291
292 return retval;
293 #endif
294 }
295
rtc_ioctl(struct inode * inode,struct file * file,unsigned int cmd,unsigned long arg)296 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
297 unsigned long arg)
298 {
299 struct rtc_time wtime;
300
301 #if RTC_IRQ
302 if (rtc_has_irq == 0) {
303 switch (cmd) {
304 case RTC_AIE_OFF:
305 case RTC_AIE_ON:
306 case RTC_PIE_OFF:
307 case RTC_PIE_ON:
308 case RTC_UIE_OFF:
309 case RTC_UIE_ON:
310 case RTC_IRQP_READ:
311 case RTC_IRQP_SET:
312 return -EINVAL;
313 };
314 }
315 #endif
316
317 switch (cmd) {
318 #if RTC_IRQ
319 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
320 {
321 mask_rtc_irq_bit(RTC_AIE);
322 return 0;
323 }
324 case RTC_AIE_ON: /* Allow alarm interrupts. */
325 {
326 set_rtc_irq_bit(RTC_AIE);
327 return 0;
328 }
329 case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
330 {
331 mask_rtc_irq_bit(RTC_PIE);
332 if (rtc_status & RTC_TIMER_ON) {
333 spin_lock_irq (&rtc_lock);
334 rtc_status &= ~RTC_TIMER_ON;
335 del_timer(&rtc_irq_timer);
336 spin_unlock_irq (&rtc_lock);
337 }
338 return 0;
339 }
340 case RTC_PIE_ON: /* Allow periodic ints */
341 {
342
343 /*
344 * We don't really want Joe User enabling more
345 * than 64Hz of interrupts on a multi-user machine.
346 */
347 if ((rtc_freq > rtc_max_user_freq) &&
348 (!capable(CAP_SYS_RESOURCE)))
349 return -EACCES;
350
351 if (!(rtc_status & RTC_TIMER_ON)) {
352 spin_lock_irq (&rtc_lock);
353 rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
354 add_timer(&rtc_irq_timer);
355 rtc_status |= RTC_TIMER_ON;
356 spin_unlock_irq (&rtc_lock);
357 }
358 set_rtc_irq_bit(RTC_PIE);
359 return 0;
360 }
361 case RTC_UIE_OFF: /* Mask ints from RTC updates. */
362 {
363 mask_rtc_irq_bit(RTC_UIE);
364 return 0;
365 }
366 case RTC_UIE_ON: /* Allow ints for RTC updates. */
367 {
368 set_rtc_irq_bit(RTC_UIE);
369 return 0;
370 }
371 #endif
372 case RTC_ALM_READ: /* Read the present alarm time */
373 {
374 /*
375 * This returns a struct rtc_time. Reading >= 0xc0
376 * means "don't care" or "match all". Only the tm_hour,
377 * tm_min, and tm_sec values are filled in.
378 */
379 memset(&wtime, 0, sizeof(struct rtc_time));
380 get_rtc_alm_time(&wtime);
381 break;
382 }
383 case RTC_ALM_SET: /* Store a time into the alarm */
384 {
385 /*
386 * This expects a struct rtc_time. Writing 0xff means
387 * "don't care" or "match all". Only the tm_hour,
388 * tm_min and tm_sec are used.
389 */
390 unsigned char hrs, min, sec;
391 struct rtc_time alm_tm;
392
393 if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
394 sizeof(struct rtc_time)))
395 return -EFAULT;
396
397 hrs = alm_tm.tm_hour;
398 min = alm_tm.tm_min;
399 sec = alm_tm.tm_sec;
400
401 spin_lock_irq(&rtc_lock);
402 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
403 RTC_ALWAYS_BCD)
404 {
405 if (sec < 60) BIN_TO_BCD(sec);
406 else sec = 0xff;
407
408 if (min < 60) BIN_TO_BCD(min);
409 else min = 0xff;
410
411 if (hrs < 24) BIN_TO_BCD(hrs);
412 else hrs = 0xff;
413 }
414 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
415 CMOS_WRITE(min, RTC_MINUTES_ALARM);
416 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
417 spin_unlock_irq(&rtc_lock);
418
419 return 0;
420 }
421 case RTC_RD_TIME: /* Read the time/date from RTC */
422 {
423 memset(&wtime, 0, sizeof(struct rtc_time));
424 get_rtc_time(&wtime);
425 break;
426 }
427 case RTC_SET_TIME: /* Set the RTC */
428 {
429 struct rtc_time rtc_tm;
430 unsigned char mon, day, hrs, min, sec, leap_yr;
431 unsigned char save_control, save_freq_select;
432 unsigned int yrs;
433 #ifdef CONFIG_DECSTATION
434 unsigned int real_yrs;
435 #endif
436
437 if (!capable(CAP_SYS_TIME))
438 return -EACCES;
439
440 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
441 sizeof(struct rtc_time)))
442 return -EFAULT;
443
444 yrs = rtc_tm.tm_year + 1900;
445 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
446 day = rtc_tm.tm_mday;
447 hrs = rtc_tm.tm_hour;
448 min = rtc_tm.tm_min;
449 sec = rtc_tm.tm_sec;
450
451 if (yrs < 1970)
452 return -EINVAL;
453
454 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
455
456 if ((mon > 12) || (day == 0))
457 return -EINVAL;
458
459 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
460 return -EINVAL;
461
462 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
463 return -EINVAL;
464
465 if ((yrs -= epoch) > 255) /* They are unsigned */
466 return -EINVAL;
467
468 spin_lock_irq(&rtc_lock);
469 #ifdef CONFIG_DECSTATION
470 real_yrs = yrs;
471 yrs = 72;
472
473 /*
474 * We want to keep the year set to 73 until March
475 * for non-leap years, so that Feb, 29th is handled
476 * correctly.
477 */
478 if (!leap_yr && mon < 3) {
479 real_yrs--;
480 yrs = 73;
481 }
482 #endif
483 /* These limits and adjustments are independant of
484 * whether the chip is in binary mode or not.
485 */
486 if (yrs > 169) {
487 spin_unlock_irq(&rtc_lock);
488 return -EINVAL;
489 }
490 if (yrs >= 100)
491 yrs -= 100;
492
493 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
494 || RTC_ALWAYS_BCD) {
495 BIN_TO_BCD(sec);
496 BIN_TO_BCD(min);
497 BIN_TO_BCD(hrs);
498 BIN_TO_BCD(day);
499 BIN_TO_BCD(mon);
500 BIN_TO_BCD(yrs);
501 }
502
503 save_control = CMOS_READ(RTC_CONTROL);
504 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
505 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
506 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
507
508 #ifdef CONFIG_DECSTATION
509 CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
510 #endif
511 CMOS_WRITE(yrs, RTC_YEAR);
512 CMOS_WRITE(mon, RTC_MONTH);
513 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
514 CMOS_WRITE(hrs, RTC_HOURS);
515 CMOS_WRITE(min, RTC_MINUTES);
516 CMOS_WRITE(sec, RTC_SECONDS);
517
518 CMOS_WRITE(save_control, RTC_CONTROL);
519 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
520
521 spin_unlock_irq(&rtc_lock);
522 return 0;
523 }
524 #if RTC_IRQ
525 case RTC_IRQP_READ: /* Read the periodic IRQ rate. */
526 {
527 return put_user(rtc_freq, (unsigned long *)arg);
528 }
529 case RTC_IRQP_SET: /* Set periodic IRQ rate. */
530 {
531 int tmp = 0;
532 unsigned char val;
533
534 /*
535 * The max we can do is 8192Hz.
536 */
537 if ((arg < 2) || (arg > 8192))
538 return -EINVAL;
539 /*
540 * We don't really want Joe User generating more
541 * than 64Hz of interrupts on a multi-user machine.
542 */
543 if ((arg > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
544 return -EACCES;
545
546 while (arg > (1<<tmp))
547 tmp++;
548
549 /*
550 * Check that the input was really a power of 2.
551 */
552 if (arg != (1<<tmp))
553 return -EINVAL;
554
555 spin_lock_irq(&rtc_lock);
556 rtc_freq = arg;
557
558 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
559 val |= (16 - tmp);
560 CMOS_WRITE(val, RTC_FREQ_SELECT);
561 spin_unlock_irq(&rtc_lock);
562 return 0;
563 }
564 #endif
565 case RTC_EPOCH_READ: /* Read the epoch. */
566 {
567 return put_user (epoch, (unsigned long *)arg);
568 }
569 case RTC_EPOCH_SET: /* Set the epoch. */
570 {
571 /*
572 * There were no RTC clocks before 1900.
573 */
574 if (arg < 1900)
575 return -EINVAL;
576
577 if (!capable(CAP_SYS_TIME))
578 return -EACCES;
579
580 epoch = arg;
581 return 0;
582 }
583 default:
584 return -ENOTTY;
585 }
586 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
587 }
588
589 /*
590 * We enforce only one user at a time here with the open/close.
591 * Also clear the previous interrupt data on an open, and clean
592 * up things on a close.
593 */
594
595 /* We use rtc_lock to protect against concurrent opens. So the BKL is not
596 * needed here. Or anywhere else in this driver. */
rtc_open(struct inode * inode,struct file * file)597 static int rtc_open(struct inode *inode, struct file *file)
598 {
599 spin_lock_irq (&rtc_lock);
600
601 if(rtc_status & RTC_IS_OPEN)
602 goto out_busy;
603
604 rtc_status |= RTC_IS_OPEN;
605
606 rtc_irq_data = 0;
607 spin_unlock_irq (&rtc_lock);
608 return 0;
609
610 out_busy:
611 spin_unlock_irq (&rtc_lock);
612 return -EBUSY;
613 }
614
rtc_fasync(int fd,struct file * filp,int on)615 static int rtc_fasync (int fd, struct file *filp, int on)
616
617 {
618 return fasync_helper (fd, filp, on, &rtc_async_queue);
619 }
620
rtc_release(struct inode * inode,struct file * file)621 static int rtc_release(struct inode *inode, struct file *file)
622 {
623 #if RTC_IRQ
624 unsigned char tmp;
625
626 if (rtc_has_irq == 0)
627 goto no_irq;
628
629 /*
630 * Turn off all interrupts once the device is no longer
631 * in use, and clear the data.
632 */
633
634 spin_lock_irq(&rtc_lock);
635 tmp = CMOS_READ(RTC_CONTROL);
636 tmp &= ~RTC_PIE;
637 tmp &= ~RTC_AIE;
638 tmp &= ~RTC_UIE;
639 CMOS_WRITE(tmp, RTC_CONTROL);
640 CMOS_READ(RTC_INTR_FLAGS);
641
642 if (rtc_status & RTC_TIMER_ON) {
643 rtc_status &= ~RTC_TIMER_ON;
644 del_timer(&rtc_irq_timer);
645 }
646 spin_unlock_irq(&rtc_lock);
647
648 if (file->f_flags & FASYNC) {
649 rtc_fasync (-1, file, 0);
650 }
651 no_irq:
652 #endif
653
654 spin_lock_irq (&rtc_lock);
655 rtc_irq_data = 0;
656 spin_unlock_irq (&rtc_lock);
657
658 /* No need for locking -- nobody else can do anything until this rmw is
659 * committed, and no timer is running. */
660 rtc_status &= ~RTC_IS_OPEN;
661 return 0;
662 }
663
664 #if RTC_IRQ
665 /* Called without the kernel lock - fine */
rtc_poll(struct file * file,poll_table * wait)666 static unsigned int rtc_poll(struct file *file, poll_table *wait)
667 {
668 unsigned long l;
669
670 if (rtc_has_irq == 0)
671 return 0;
672
673 poll_wait(file, &rtc_wait, wait);
674
675 spin_lock_irq (&rtc_lock);
676 l = rtc_irq_data;
677 spin_unlock_irq (&rtc_lock);
678
679 if (l != 0)
680 return POLLIN | POLLRDNORM;
681 return 0;
682 }
683 #endif
684
685 /*
686 * The various file operations we support.
687 */
688
689 static struct file_operations rtc_fops = {
690 owner: THIS_MODULE,
691 llseek: no_llseek,
692 read: rtc_read,
693 #if RTC_IRQ
694 poll: rtc_poll,
695 #endif
696 ioctl: rtc_ioctl,
697 open: rtc_open,
698 release: rtc_release,
699 fasync: rtc_fasync,
700 };
701
702 static struct miscdevice rtc_dev=
703 {
704 RTC_MINOR,
705 "rtc",
706 &rtc_fops
707 };
708
rtc_init(void)709 static int __init rtc_init(void)
710 {
711 #if defined(__alpha__) || defined(__mips__)
712 unsigned int year, ctrl;
713 unsigned long uip_watchdog;
714 char *guess = NULL;
715 #endif
716 #ifdef __sparc__
717 struct linux_ebus *ebus;
718 struct linux_ebus_device *edev;
719 #ifdef __sparc_v9__
720 struct isa_bridge *isa_br;
721 struct isa_device *isa_dev;
722 #endif
723 #endif
724 #ifndef __sparc__
725 void *r;
726 #endif
727
728 #ifdef __sparc__
729 for_each_ebus(ebus) {
730 for_each_ebusdev(edev, ebus) {
731 if(strcmp(edev->prom_name, "rtc") == 0) {
732 rtc_port = edev->resource[0].start;
733 rtc_irq = edev->irqs[0];
734 goto found;
735 }
736 }
737 }
738 #ifdef __sparc_v9__
739 for_each_isa(isa_br) {
740 for_each_isadev(isa_dev, isa_br) {
741 if (strcmp(isa_dev->prom_name, "rtc") == 0) {
742 rtc_port = isa_dev->resource.start;
743 rtc_irq = isa_dev->irq;
744 goto found;
745 }
746 }
747 }
748 #endif
749 printk(KERN_ERR "rtc_init: no PC rtc found\n");
750 return -EIO;
751
752 found:
753 if (rtc_irq == PCI_IRQ_NONE) {
754 rtc_has_irq = 0;
755 goto no_irq;
756 }
757
758 /*
759 * XXX Interrupt pin #7 in Espresso is shared between RTC and
760 * PCI Slot 2 INTA# (and some INTx# in Slot 1). SA_INTERRUPT here
761 * is asking for trouble with add-on boards. Change to SA_SHIRQ.
762 */
763 if (request_irq(rtc_irq, rtc_interrupt, SA_INTERRUPT, "rtc", (void *)&rtc_port)) {
764 /*
765 * Standard way for sparc to print irq's is to use
766 * __irq_itoa(). I think for EBus it's ok to use %d.
767 */
768 printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
769 return -EIO;
770 }
771 no_irq:
772 #else
773 if (RTC_IOMAPPED)
774 r = request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
775 else
776 r = request_mem_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
777 if (!r) {
778 printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
779 (long)(RTC_PORT(0)));
780 return -EIO;
781 }
782
783 #if RTC_IRQ
784 if(request_irq(RTC_IRQ, rtc_interrupt, SA_INTERRUPT, "rtc", NULL)) {
785 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
786 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
787 if (RTC_IOMAPPED)
788 release_region(RTC_PORT(0), RTC_IO_EXTENT);
789 else
790 release_mem_region(RTC_PORT(0), RTC_IO_EXTENT);
791 return -EIO;
792 }
793 #endif
794
795 #endif /* __sparc__ vs. others */
796
797 misc_register(&rtc_dev);
798 create_proc_read_entry ("driver/rtc", 0, 0, rtc_read_proc, NULL);
799
800 #if defined(__alpha__) || defined(__mips__)
801 rtc_freq = HZ;
802
803 /* Each operating system on an Alpha uses its own epoch.
804 Let's try to guess which one we are using now. */
805
806 uip_watchdog = jiffies;
807 if (rtc_is_updating() != 0)
808 while (jiffies - uip_watchdog < 2*HZ/100) {
809 barrier();
810 cpu_relax();
811 }
812
813 spin_lock_irq(&rtc_lock);
814 year = CMOS_READ(RTC_YEAR);
815 ctrl = CMOS_READ(RTC_CONTROL);
816 spin_unlock_irq(&rtc_lock);
817
818 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
819 BCD_TO_BIN(year); /* This should never happen... */
820
821 if (year < 20) {
822 epoch = 2000;
823 guess = "SRM (post-2000)";
824 } else if (year >= 20 && year < 48) {
825 epoch = 1980;
826 guess = "ARC console";
827 } else if (year >= 48 && year < 72) {
828 epoch = 1952;
829 guess = "Digital UNIX";
830 #if defined(__mips__)
831 } else if (year >= 72 && year < 74) {
832 epoch = 2000;
833 guess = "Digital DECstation";
834 #else
835 } else if (year >= 70) {
836 epoch = 1900;
837 guess = "Standard PC (1900)";
838 #endif
839 }
840 if (guess)
841 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", guess, epoch);
842 #endif
843 #if RTC_IRQ
844 if (rtc_has_irq == 0)
845 goto no_irq2;
846
847 init_timer(&rtc_irq_timer);
848 rtc_irq_timer.function = rtc_dropped_irq;
849 spin_lock_irq(&rtc_lock);
850 /* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
851 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), RTC_FREQ_SELECT);
852 spin_unlock_irq(&rtc_lock);
853 rtc_freq = 1024;
854 no_irq2:
855 #endif
856
857 (void) init_sysctl();
858
859 printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
860
861 return 0;
862 }
863
rtc_exit(void)864 static void __exit rtc_exit (void)
865 {
866 cleanup_sysctl();
867 remove_proc_entry ("driver/rtc", NULL);
868 misc_deregister(&rtc_dev);
869
870 #ifdef __sparc__
871 if (rtc_has_irq)
872 free_irq (rtc_irq, &rtc_port);
873 #else
874 if (RTC_IOMAPPED)
875 release_region(RTC_PORT(0), RTC_IO_EXTENT);
876 else
877 release_mem_region(RTC_PORT(0), RTC_IO_EXTENT);
878 #if RTC_IRQ
879 if (rtc_has_irq)
880 free_irq (RTC_IRQ, NULL);
881 #endif
882 #endif /* __sparc__ */
883 }
884
885 module_init(rtc_init);
886 module_exit(rtc_exit);
887 EXPORT_NO_SYMBOLS;
888
889 #if RTC_IRQ
890 /*
891 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
892 * (usually during an IDE disk interrupt, with IRQ unmasking off)
893 * Since the interrupt handler doesn't get called, the IRQ status
894 * byte doesn't get read, and the RTC stops generating interrupts.
895 * A timer is set, and will call this function if/when that happens.
896 * To get it out of this stalled state, we just read the status.
897 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
898 * (You *really* shouldn't be trying to use a non-realtime system
899 * for something that requires a steady > 1KHz signal anyways.)
900 */
901
rtc_dropped_irq(unsigned long data)902 static void rtc_dropped_irq(unsigned long data)
903 {
904 unsigned long freq;
905
906 spin_lock_irq (&rtc_lock);
907
908 /* Just in case someone disabled the timer from behind our back... */
909 if (rtc_status & RTC_TIMER_ON)
910 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
911
912 rtc_irq_data += ((rtc_freq/HZ)<<8);
913 rtc_irq_data &= ~0xff;
914 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */
915
916 freq = rtc_freq;
917
918 spin_unlock_irq(&rtc_lock);
919
920 printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", freq);
921
922 /* Now we have new data */
923 wake_up_interruptible(&rtc_wait);
924
925 kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
926 }
927 #endif
928
929 /*
930 * Info exported via "/proc/driver/rtc".
931 */
932
rtc_proc_output(char * buf)933 static int rtc_proc_output (char *buf)
934 {
935 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
936 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
937 char *p;
938 struct rtc_time tm;
939 unsigned char batt, ctrl;
940 unsigned long freq;
941
942 spin_lock_irq(&rtc_lock);
943 batt = CMOS_READ(RTC_VALID) & RTC_VRT;
944 ctrl = CMOS_READ(RTC_CONTROL);
945 freq = rtc_freq;
946 spin_unlock_irq(&rtc_lock);
947
948 p = buf;
949
950 get_rtc_time(&tm);
951
952 /*
953 * There is no way to tell if the luser has the RTC set for local
954 * time or for Universal Standard Time (GMT). Probably local though.
955 */
956 p += sprintf(p,
957 "rtc_time\t: %02d:%02d:%02d\n"
958 "rtc_date\t: %04d-%02d-%02d\n"
959 "rtc_epoch\t: %04lu\n",
960 tm.tm_hour, tm.tm_min, tm.tm_sec,
961 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
962
963 get_rtc_alm_time(&tm);
964
965 /*
966 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
967 * match any value for that particular field. Values that are
968 * greater than a valid time, but less than 0xc0 shouldn't appear.
969 */
970 p += sprintf(p, "alarm\t\t: ");
971 if (tm.tm_hour <= 24)
972 p += sprintf(p, "%02d:", tm.tm_hour);
973 else
974 p += sprintf(p, "**:");
975
976 if (tm.tm_min <= 59)
977 p += sprintf(p, "%02d:", tm.tm_min);
978 else
979 p += sprintf(p, "**:");
980
981 if (tm.tm_sec <= 59)
982 p += sprintf(p, "%02d\n", tm.tm_sec);
983 else
984 p += sprintf(p, "**\n");
985
986 p += sprintf(p,
987 "DST_enable\t: %s\n"
988 "BCD\t\t: %s\n"
989 "24hr\t\t: %s\n"
990 "square_wave\t: %s\n"
991 "alarm_IRQ\t: %s\n"
992 "update_IRQ\t: %s\n"
993 "periodic_IRQ\t: %s\n"
994 "periodic_freq\t: %ld\n"
995 "batt_status\t: %s\n",
996 YN(RTC_DST_EN),
997 NY(RTC_DM_BINARY),
998 YN(RTC_24H),
999 YN(RTC_SQWE),
1000 YN(RTC_AIE),
1001 YN(RTC_UIE),
1002 YN(RTC_PIE),
1003 freq,
1004 batt ? "okay" : "dead");
1005
1006 return p - buf;
1007 #undef YN
1008 #undef NY
1009 }
1010
rtc_read_proc(char * page,char ** start,off_t off,int count,int * eof,void * data)1011 static int rtc_read_proc(char *page, char **start, off_t off,
1012 int count, int *eof, void *data)
1013 {
1014 int len = rtc_proc_output (page);
1015 if (len <= off+count) *eof = 1;
1016 *start = page + off;
1017 len -= off;
1018 if (len>count) len = count;
1019 if (len<0) len = 0;
1020 return len;
1021 }
1022
1023 /*
1024 * Returns true if a clock update is in progress
1025 */
1026 /* FIXME shouldn't this be above rtc_init to make it fully inlined? */
rtc_is_updating(void)1027 static inline unsigned char rtc_is_updating(void)
1028 {
1029 unsigned char uip;
1030
1031 spin_lock_irq(&rtc_lock);
1032 uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
1033 spin_unlock_irq(&rtc_lock);
1034 return uip;
1035 }
1036
get_rtc_time(struct rtc_time * rtc_tm)1037 static void get_rtc_time(struct rtc_time *rtc_tm)
1038 {
1039 unsigned long uip_watchdog = jiffies;
1040 unsigned char ctrl;
1041 #ifdef CONFIG_DECSTATION
1042 unsigned int real_year;
1043 #endif
1044
1045 /*
1046 * read RTC once any update in progress is done. The update
1047 * can take just over 2ms. We wait 10 to 20ms. There is no need to
1048 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1049 * If you need to know *exactly* when a second has started, enable
1050 * periodic update complete interrupts, (via ioctl) and then
1051 * immediately read /dev/rtc which will block until you get the IRQ.
1052 * Once the read clears, read the RTC time (again via ioctl). Easy.
1053 */
1054
1055 if (rtc_is_updating() != 0)
1056 while (jiffies - uip_watchdog < 2*HZ/100) {
1057 barrier();
1058 cpu_relax();
1059 }
1060
1061 /*
1062 * Only the values that we read from the RTC are set. We leave
1063 * tm_wday, tm_yday and tm_isdst untouched. Even though the
1064 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
1065 * by the RTC when initially set to a non-zero value.
1066 */
1067 spin_lock_irq(&rtc_lock);
1068 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
1069 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
1070 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
1071 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
1072 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
1073 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
1074 #ifdef CONFIG_DECSTATION
1075 real_year = CMOS_READ(RTC_DEC_YEAR);
1076 #endif
1077 ctrl = CMOS_READ(RTC_CONTROL);
1078 spin_unlock_irq(&rtc_lock);
1079
1080 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1081 {
1082 BCD_TO_BIN(rtc_tm->tm_sec);
1083 BCD_TO_BIN(rtc_tm->tm_min);
1084 BCD_TO_BIN(rtc_tm->tm_hour);
1085 BCD_TO_BIN(rtc_tm->tm_mday);
1086 BCD_TO_BIN(rtc_tm->tm_mon);
1087 BCD_TO_BIN(rtc_tm->tm_year);
1088 }
1089
1090 #ifdef CONFIG_DECSTATION
1091 rtc_tm->tm_year += real_year - 72;
1092 #endif
1093
1094 /*
1095 * Account for differences between how the RTC uses the values
1096 * and how they are defined in a struct rtc_time;
1097 */
1098 if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
1099 rtc_tm->tm_year += 100;
1100
1101 rtc_tm->tm_mon--;
1102 }
1103
get_rtc_alm_time(struct rtc_time * alm_tm)1104 static void get_rtc_alm_time(struct rtc_time *alm_tm)
1105 {
1106 unsigned char ctrl;
1107
1108 /*
1109 * Only the values that we read from the RTC are set. That
1110 * means only tm_hour, tm_min, and tm_sec.
1111 */
1112 spin_lock_irq(&rtc_lock);
1113 alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
1114 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
1115 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
1116 ctrl = CMOS_READ(RTC_CONTROL);
1117 spin_unlock_irq(&rtc_lock);
1118
1119 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1120 {
1121 BCD_TO_BIN(alm_tm->tm_sec);
1122 BCD_TO_BIN(alm_tm->tm_min);
1123 BCD_TO_BIN(alm_tm->tm_hour);
1124 }
1125 }
1126
1127 #if RTC_IRQ
1128 /*
1129 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1130 * Rumour has it that if you frob the interrupt enable/disable
1131 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1132 * ensure you actually start getting interrupts. Probably for
1133 * compatibility with older/broken chipset RTC implementations.
1134 * We also clear out any old irq data after an ioctl() that
1135 * meddles with the interrupt enable/disable bits.
1136 */
1137
mask_rtc_irq_bit(unsigned char bit)1138 static void mask_rtc_irq_bit(unsigned char bit)
1139 {
1140 unsigned char val;
1141
1142 spin_lock_irq(&rtc_lock);
1143 val = CMOS_READ(RTC_CONTROL);
1144 val &= ~bit;
1145 CMOS_WRITE(val, RTC_CONTROL);
1146 CMOS_READ(RTC_INTR_FLAGS);
1147
1148 rtc_irq_data = 0;
1149 spin_unlock_irq(&rtc_lock);
1150 }
1151
set_rtc_irq_bit(unsigned char bit)1152 static void set_rtc_irq_bit(unsigned char bit)
1153 {
1154 unsigned char val;
1155
1156 spin_lock_irq(&rtc_lock);
1157 val = CMOS_READ(RTC_CONTROL);
1158 val |= bit;
1159 CMOS_WRITE(val, RTC_CONTROL);
1160 CMOS_READ(RTC_INTR_FLAGS);
1161
1162 rtc_irq_data = 0;
1163 spin_unlock_irq(&rtc_lock);
1164 }
1165 #endif
1166
1167 MODULE_AUTHOR("Paul Gortmaker");
1168 MODULE_LICENSE("GPL");
1169