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 * 1.11 Takashi Iwai: Kernel access functions
45 * rtc_register/rtc_unregister/rtc_control
46 * 1.11a Daniele Bellucci: Audit create_proc_read_entry in rtc_init
47 * 1.12 Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
48 * CONFIG_HPET_EMULATE_RTC
49 * 1.12a Maciej W. Rozycki: Handle memory-mapped chips properly.
50 * 1.12ac Alan Cox: Allow read access to the day of week register
51 * 1.12b David John: Remove calls to the BKL.
52 */
53
54 #define RTC_VERSION "1.12b"
55
56 /*
57 * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
58 * interrupts disabled. Due to the index-port/data-port (0x70/0x71)
59 * design of the RTC, we don't want two different things trying to
60 * get to it at once. (e.g. the periodic 11 min sync from
61 * kernel/time/ntp.c vs. this driver.)
62 */
63
64 #include <linux/interrupt.h>
65 #include <linux/module.h>
66 #include <linux/kernel.h>
67 #include <linux/types.h>
68 #include <linux/miscdevice.h>
69 #include <linux/ioport.h>
70 #include <linux/fcntl.h>
71 #include <linux/mc146818rtc.h>
72 #include <linux/init.h>
73 #include <linux/poll.h>
74 #include <linux/proc_fs.h>
75 #include <linux/seq_file.h>
76 #include <linux/spinlock.h>
77 #include <linux/sched.h>
78 #include <linux/sysctl.h>
79 #include <linux/wait.h>
80 #include <linux/bcd.h>
81 #include <linux/delay.h>
82 #include <linux/uaccess.h>
83 #include <linux/ratelimit.h>
84
85 #include <asm/current.h>
86
87 #ifdef CONFIG_X86
88 #include <asm/hpet.h>
89 #endif
90
91 #ifdef CONFIG_SPARC32
92 #include <linux/of.h>
93 #include <linux/of_device.h>
94 #include <asm/io.h>
95
96 static unsigned long rtc_port;
97 static int rtc_irq;
98 #endif
99
100 #ifdef CONFIG_HPET_EMULATE_RTC
101 #undef RTC_IRQ
102 #endif
103
104 #ifdef RTC_IRQ
105 static int rtc_has_irq = 1;
106 #endif
107
108 #ifndef CONFIG_HPET_EMULATE_RTC
109 #define is_hpet_enabled() 0
110 #define hpet_set_alarm_time(hrs, min, sec) 0
111 #define hpet_set_periodic_freq(arg) 0
112 #define hpet_mask_rtc_irq_bit(arg) 0
113 #define hpet_set_rtc_irq_bit(arg) 0
114 #define hpet_rtc_timer_init() do { } while (0)
115 #define hpet_rtc_dropped_irq() 0
116 #define hpet_register_irq_handler(h) ({ 0; })
117 #define hpet_unregister_irq_handler(h) ({ 0; })
118 #ifdef RTC_IRQ
hpet_rtc_interrupt(int irq,void * dev_id)119 static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
120 {
121 return 0;
122 }
123 #endif
124 #endif
125
126 /*
127 * We sponge a minor off of the misc major. No need slurping
128 * up another valuable major dev number for this. If you add
129 * an ioctl, make sure you don't conflict with SPARC's RTC
130 * ioctls.
131 */
132
133 static struct fasync_struct *rtc_async_queue;
134
135 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
136
137 #ifdef RTC_IRQ
138 static void rtc_dropped_irq(unsigned long data);
139
140 static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq, 0, 0);
141 #endif
142
143 static ssize_t rtc_read(struct file *file, char __user *buf,
144 size_t count, loff_t *ppos);
145
146 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
147 static void rtc_get_rtc_time(struct rtc_time *rtc_tm);
148
149 #ifdef RTC_IRQ
150 static unsigned int rtc_poll(struct file *file, poll_table *wait);
151 #endif
152
153 static void get_rtc_alm_time(struct rtc_time *alm_tm);
154 #ifdef RTC_IRQ
155 static void set_rtc_irq_bit_locked(unsigned char bit);
156 static void mask_rtc_irq_bit_locked(unsigned char bit);
157
set_rtc_irq_bit(unsigned char bit)158 static inline void set_rtc_irq_bit(unsigned char bit)
159 {
160 spin_lock_irq(&rtc_lock);
161 set_rtc_irq_bit_locked(bit);
162 spin_unlock_irq(&rtc_lock);
163 }
164
mask_rtc_irq_bit(unsigned char bit)165 static void mask_rtc_irq_bit(unsigned char bit)
166 {
167 spin_lock_irq(&rtc_lock);
168 mask_rtc_irq_bit_locked(bit);
169 spin_unlock_irq(&rtc_lock);
170 }
171 #endif
172
173 #ifdef CONFIG_PROC_FS
174 static int rtc_proc_open(struct inode *inode, struct file *file);
175 #endif
176
177 /*
178 * Bits in rtc_status. (6 bits of room for future expansion)
179 */
180
181 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
182 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
183
184 /*
185 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
186 * protected by the spin lock rtc_lock. However, ioctl can still disable the
187 * timer in rtc_status and then with del_timer after the interrupt has read
188 * rtc_status but before mod_timer is called, which would then reenable the
189 * timer (but you would need to have an awful timing before you'd trip on it)
190 */
191 static unsigned long rtc_status; /* bitmapped status byte. */
192 static unsigned long rtc_freq; /* Current periodic IRQ rate */
193 static unsigned long rtc_irq_data; /* our output to the world */
194 static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */
195
196 #ifdef RTC_IRQ
197 /*
198 * rtc_task_lock nests inside rtc_lock.
199 */
200 static DEFINE_SPINLOCK(rtc_task_lock);
201 static rtc_task_t *rtc_callback;
202 #endif
203
204 /*
205 * If this driver ever becomes modularised, it will be really nice
206 * to make the epoch retain its value across module reload...
207 */
208
209 static unsigned long epoch = 1900; /* year corresponding to 0x00 */
210
211 static const unsigned char days_in_mo[] =
212 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
213
214 /*
215 * Returns true if a clock update is in progress
216 */
rtc_is_updating(void)217 static inline unsigned char rtc_is_updating(void)
218 {
219 unsigned long flags;
220 unsigned char uip;
221
222 spin_lock_irqsave(&rtc_lock, flags);
223 uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
224 spin_unlock_irqrestore(&rtc_lock, flags);
225 return uip;
226 }
227
228 #ifdef RTC_IRQ
229 /*
230 * A very tiny interrupt handler. It runs with IRQF_DISABLED set,
231 * but there is possibility of conflicting with the set_rtc_mmss()
232 * call (the rtc irq and the timer irq can easily run at the same
233 * time in two different CPUs). So we need to serialize
234 * accesses to the chip with the rtc_lock spinlock that each
235 * architecture should implement in the timer code.
236 * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
237 */
238
rtc_interrupt(int irq,void * dev_id)239 static irqreturn_t rtc_interrupt(int irq, void *dev_id)
240 {
241 /*
242 * Can be an alarm interrupt, update complete interrupt,
243 * or a periodic interrupt. We store the status in the
244 * low byte and the number of interrupts received since
245 * the last read in the remainder of rtc_irq_data.
246 */
247
248 spin_lock(&rtc_lock);
249 rtc_irq_data += 0x100;
250 rtc_irq_data &= ~0xff;
251 if (is_hpet_enabled()) {
252 /*
253 * In this case it is HPET RTC interrupt handler
254 * calling us, with the interrupt information
255 * passed as arg1, instead of irq.
256 */
257 rtc_irq_data |= (unsigned long)irq & 0xF0;
258 } else {
259 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
260 }
261
262 if (rtc_status & RTC_TIMER_ON)
263 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
264
265 spin_unlock(&rtc_lock);
266
267 /* Now do the rest of the actions */
268 spin_lock(&rtc_task_lock);
269 if (rtc_callback)
270 rtc_callback->func(rtc_callback->private_data);
271 spin_unlock(&rtc_task_lock);
272 wake_up_interruptible(&rtc_wait);
273
274 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
275
276 return IRQ_HANDLED;
277 }
278 #endif
279
280 /*
281 * sysctl-tuning infrastructure.
282 */
283 static ctl_table rtc_table[] = {
284 {
285 .procname = "max-user-freq",
286 .data = &rtc_max_user_freq,
287 .maxlen = sizeof(int),
288 .mode = 0644,
289 .proc_handler = proc_dointvec,
290 },
291 { }
292 };
293
294 static ctl_table rtc_root[] = {
295 {
296 .procname = "rtc",
297 .mode = 0555,
298 .child = rtc_table,
299 },
300 { }
301 };
302
303 static ctl_table dev_root[] = {
304 {
305 .procname = "dev",
306 .mode = 0555,
307 .child = rtc_root,
308 },
309 { }
310 };
311
312 static struct ctl_table_header *sysctl_header;
313
init_sysctl(void)314 static int __init init_sysctl(void)
315 {
316 sysctl_header = register_sysctl_table(dev_root);
317 return 0;
318 }
319
cleanup_sysctl(void)320 static void __exit cleanup_sysctl(void)
321 {
322 unregister_sysctl_table(sysctl_header);
323 }
324
325 /*
326 * Now all the various file operations that we export.
327 */
328
rtc_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)329 static ssize_t rtc_read(struct file *file, char __user *buf,
330 size_t count, loff_t *ppos)
331 {
332 #ifndef RTC_IRQ
333 return -EIO;
334 #else
335 DECLARE_WAITQUEUE(wait, current);
336 unsigned long data;
337 ssize_t retval;
338
339 if (rtc_has_irq == 0)
340 return -EIO;
341
342 /*
343 * Historically this function used to assume that sizeof(unsigned long)
344 * is the same in userspace and kernelspace. This lead to problems
345 * for configurations with multiple ABIs such a the MIPS o32 and 64
346 * ABIs supported on the same kernel. So now we support read of both
347 * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
348 * userspace ABI.
349 */
350 if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
351 return -EINVAL;
352
353 add_wait_queue(&rtc_wait, &wait);
354
355 do {
356 /* First make it right. Then make it fast. Putting this whole
357 * block within the parentheses of a while would be too
358 * confusing. And no, xchg() is not the answer. */
359
360 __set_current_state(TASK_INTERRUPTIBLE);
361
362 spin_lock_irq(&rtc_lock);
363 data = rtc_irq_data;
364 rtc_irq_data = 0;
365 spin_unlock_irq(&rtc_lock);
366
367 if (data != 0)
368 break;
369
370 if (file->f_flags & O_NONBLOCK) {
371 retval = -EAGAIN;
372 goto out;
373 }
374 if (signal_pending(current)) {
375 retval = -ERESTARTSYS;
376 goto out;
377 }
378 schedule();
379 } while (1);
380
381 if (count == sizeof(unsigned int)) {
382 retval = put_user(data,
383 (unsigned int __user *)buf) ?: sizeof(int);
384 } else {
385 retval = put_user(data,
386 (unsigned long __user *)buf) ?: sizeof(long);
387 }
388 if (!retval)
389 retval = count;
390 out:
391 __set_current_state(TASK_RUNNING);
392 remove_wait_queue(&rtc_wait, &wait);
393
394 return retval;
395 #endif
396 }
397
rtc_do_ioctl(unsigned int cmd,unsigned long arg,int kernel)398 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
399 {
400 struct rtc_time wtime;
401
402 #ifdef RTC_IRQ
403 if (rtc_has_irq == 0) {
404 switch (cmd) {
405 case RTC_AIE_OFF:
406 case RTC_AIE_ON:
407 case RTC_PIE_OFF:
408 case RTC_PIE_ON:
409 case RTC_UIE_OFF:
410 case RTC_UIE_ON:
411 case RTC_IRQP_READ:
412 case RTC_IRQP_SET:
413 return -EINVAL;
414 };
415 }
416 #endif
417
418 switch (cmd) {
419 #ifdef RTC_IRQ
420 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
421 {
422 mask_rtc_irq_bit(RTC_AIE);
423 return 0;
424 }
425 case RTC_AIE_ON: /* Allow alarm interrupts. */
426 {
427 set_rtc_irq_bit(RTC_AIE);
428 return 0;
429 }
430 case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
431 {
432 /* can be called from isr via rtc_control() */
433 unsigned long flags;
434
435 spin_lock_irqsave(&rtc_lock, flags);
436 mask_rtc_irq_bit_locked(RTC_PIE);
437 if (rtc_status & RTC_TIMER_ON) {
438 rtc_status &= ~RTC_TIMER_ON;
439 del_timer(&rtc_irq_timer);
440 }
441 spin_unlock_irqrestore(&rtc_lock, flags);
442
443 return 0;
444 }
445 case RTC_PIE_ON: /* Allow periodic ints */
446 {
447 /* can be called from isr via rtc_control() */
448 unsigned long flags;
449
450 /*
451 * We don't really want Joe User enabling more
452 * than 64Hz of interrupts on a multi-user machine.
453 */
454 if (!kernel && (rtc_freq > rtc_max_user_freq) &&
455 (!capable(CAP_SYS_RESOURCE)))
456 return -EACCES;
457
458 spin_lock_irqsave(&rtc_lock, flags);
459 if (!(rtc_status & RTC_TIMER_ON)) {
460 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq +
461 2*HZ/100);
462 rtc_status |= RTC_TIMER_ON;
463 }
464 set_rtc_irq_bit_locked(RTC_PIE);
465 spin_unlock_irqrestore(&rtc_lock, flags);
466
467 return 0;
468 }
469 case RTC_UIE_OFF: /* Mask ints from RTC updates. */
470 {
471 mask_rtc_irq_bit(RTC_UIE);
472 return 0;
473 }
474 case RTC_UIE_ON: /* Allow ints for RTC updates. */
475 {
476 set_rtc_irq_bit(RTC_UIE);
477 return 0;
478 }
479 #endif
480 case RTC_ALM_READ: /* Read the present alarm time */
481 {
482 /*
483 * This returns a struct rtc_time. Reading >= 0xc0
484 * means "don't care" or "match all". Only the tm_hour,
485 * tm_min, and tm_sec values are filled in.
486 */
487 memset(&wtime, 0, sizeof(struct rtc_time));
488 get_rtc_alm_time(&wtime);
489 break;
490 }
491 case RTC_ALM_SET: /* Store a time into the alarm */
492 {
493 /*
494 * This expects a struct rtc_time. Writing 0xff means
495 * "don't care" or "match all". Only the tm_hour,
496 * tm_min and tm_sec are used.
497 */
498 unsigned char hrs, min, sec;
499 struct rtc_time alm_tm;
500
501 if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg,
502 sizeof(struct rtc_time)))
503 return -EFAULT;
504
505 hrs = alm_tm.tm_hour;
506 min = alm_tm.tm_min;
507 sec = alm_tm.tm_sec;
508
509 spin_lock_irq(&rtc_lock);
510 if (hpet_set_alarm_time(hrs, min, sec)) {
511 /*
512 * Fallthru and set alarm time in CMOS too,
513 * so that we will get proper value in RTC_ALM_READ
514 */
515 }
516 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
517 RTC_ALWAYS_BCD) {
518 if (sec < 60)
519 sec = bin2bcd(sec);
520 else
521 sec = 0xff;
522
523 if (min < 60)
524 min = bin2bcd(min);
525 else
526 min = 0xff;
527
528 if (hrs < 24)
529 hrs = bin2bcd(hrs);
530 else
531 hrs = 0xff;
532 }
533 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
534 CMOS_WRITE(min, RTC_MINUTES_ALARM);
535 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
536 spin_unlock_irq(&rtc_lock);
537
538 return 0;
539 }
540 case RTC_RD_TIME: /* Read the time/date from RTC */
541 {
542 memset(&wtime, 0, sizeof(struct rtc_time));
543 rtc_get_rtc_time(&wtime);
544 break;
545 }
546 case RTC_SET_TIME: /* Set the RTC */
547 {
548 struct rtc_time rtc_tm;
549 unsigned char mon, day, hrs, min, sec, leap_yr;
550 unsigned char save_control, save_freq_select;
551 unsigned int yrs;
552 #ifdef CONFIG_MACH_DECSTATION
553 unsigned int real_yrs;
554 #endif
555
556 if (!capable(CAP_SYS_TIME))
557 return -EACCES;
558
559 if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
560 sizeof(struct rtc_time)))
561 return -EFAULT;
562
563 yrs = rtc_tm.tm_year + 1900;
564 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
565 day = rtc_tm.tm_mday;
566 hrs = rtc_tm.tm_hour;
567 min = rtc_tm.tm_min;
568 sec = rtc_tm.tm_sec;
569
570 if (yrs < 1970)
571 return -EINVAL;
572
573 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
574
575 if ((mon > 12) || (day == 0))
576 return -EINVAL;
577
578 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
579 return -EINVAL;
580
581 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
582 return -EINVAL;
583
584 yrs -= epoch;
585 if (yrs > 255) /* They are unsigned */
586 return -EINVAL;
587
588 spin_lock_irq(&rtc_lock);
589 #ifdef CONFIG_MACH_DECSTATION
590 real_yrs = yrs;
591 yrs = 72;
592
593 /*
594 * We want to keep the year set to 73 until March
595 * for non-leap years, so that Feb, 29th is handled
596 * correctly.
597 */
598 if (!leap_yr && mon < 3) {
599 real_yrs--;
600 yrs = 73;
601 }
602 #endif
603 /* These limits and adjustments are independent of
604 * whether the chip is in binary mode or not.
605 */
606 if (yrs > 169) {
607 spin_unlock_irq(&rtc_lock);
608 return -EINVAL;
609 }
610 if (yrs >= 100)
611 yrs -= 100;
612
613 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
614 || RTC_ALWAYS_BCD) {
615 sec = bin2bcd(sec);
616 min = bin2bcd(min);
617 hrs = bin2bcd(hrs);
618 day = bin2bcd(day);
619 mon = bin2bcd(mon);
620 yrs = bin2bcd(yrs);
621 }
622
623 save_control = CMOS_READ(RTC_CONTROL);
624 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
625 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
626 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
627
628 #ifdef CONFIG_MACH_DECSTATION
629 CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
630 #endif
631 CMOS_WRITE(yrs, RTC_YEAR);
632 CMOS_WRITE(mon, RTC_MONTH);
633 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
634 CMOS_WRITE(hrs, RTC_HOURS);
635 CMOS_WRITE(min, RTC_MINUTES);
636 CMOS_WRITE(sec, RTC_SECONDS);
637
638 CMOS_WRITE(save_control, RTC_CONTROL);
639 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
640
641 spin_unlock_irq(&rtc_lock);
642 return 0;
643 }
644 #ifdef RTC_IRQ
645 case RTC_IRQP_READ: /* Read the periodic IRQ rate. */
646 {
647 return put_user(rtc_freq, (unsigned long __user *)arg);
648 }
649 case RTC_IRQP_SET: /* Set periodic IRQ rate. */
650 {
651 int tmp = 0;
652 unsigned char val;
653 /* can be called from isr via rtc_control() */
654 unsigned long flags;
655
656 /*
657 * The max we can do is 8192Hz.
658 */
659 if ((arg < 2) || (arg > 8192))
660 return -EINVAL;
661 /*
662 * We don't really want Joe User generating more
663 * than 64Hz of interrupts on a multi-user machine.
664 */
665 if (!kernel && (arg > rtc_max_user_freq) &&
666 !capable(CAP_SYS_RESOURCE))
667 return -EACCES;
668
669 while (arg > (1<<tmp))
670 tmp++;
671
672 /*
673 * Check that the input was really a power of 2.
674 */
675 if (arg != (1<<tmp))
676 return -EINVAL;
677
678 rtc_freq = arg;
679
680 spin_lock_irqsave(&rtc_lock, flags);
681 if (hpet_set_periodic_freq(arg)) {
682 spin_unlock_irqrestore(&rtc_lock, flags);
683 return 0;
684 }
685
686 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
687 val |= (16 - tmp);
688 CMOS_WRITE(val, RTC_FREQ_SELECT);
689 spin_unlock_irqrestore(&rtc_lock, flags);
690 return 0;
691 }
692 #endif
693 case RTC_EPOCH_READ: /* Read the epoch. */
694 {
695 return put_user(epoch, (unsigned long __user *)arg);
696 }
697 case RTC_EPOCH_SET: /* Set the epoch. */
698 {
699 /*
700 * There were no RTC clocks before 1900.
701 */
702 if (arg < 1900)
703 return -EINVAL;
704
705 if (!capable(CAP_SYS_TIME))
706 return -EACCES;
707
708 epoch = arg;
709 return 0;
710 }
711 default:
712 return -ENOTTY;
713 }
714 return copy_to_user((void __user *)arg,
715 &wtime, sizeof wtime) ? -EFAULT : 0;
716 }
717
rtc_ioctl(struct file * file,unsigned int cmd,unsigned long arg)718 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
719 {
720 long ret;
721 ret = rtc_do_ioctl(cmd, arg, 0);
722 return ret;
723 }
724
725 /*
726 * We enforce only one user at a time here with the open/close.
727 * Also clear the previous interrupt data on an open, and clean
728 * up things on a close.
729 */
rtc_open(struct inode * inode,struct file * file)730 static int rtc_open(struct inode *inode, struct file *file)
731 {
732 spin_lock_irq(&rtc_lock);
733
734 if (rtc_status & RTC_IS_OPEN)
735 goto out_busy;
736
737 rtc_status |= RTC_IS_OPEN;
738
739 rtc_irq_data = 0;
740 spin_unlock_irq(&rtc_lock);
741 return 0;
742
743 out_busy:
744 spin_unlock_irq(&rtc_lock);
745 return -EBUSY;
746 }
747
rtc_fasync(int fd,struct file * filp,int on)748 static int rtc_fasync(int fd, struct file *filp, int on)
749 {
750 return fasync_helper(fd, filp, on, &rtc_async_queue);
751 }
752
rtc_release(struct inode * inode,struct file * file)753 static int rtc_release(struct inode *inode, struct file *file)
754 {
755 #ifdef RTC_IRQ
756 unsigned char tmp;
757
758 if (rtc_has_irq == 0)
759 goto no_irq;
760
761 /*
762 * Turn off all interrupts once the device is no longer
763 * in use, and clear the data.
764 */
765
766 spin_lock_irq(&rtc_lock);
767 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
768 tmp = CMOS_READ(RTC_CONTROL);
769 tmp &= ~RTC_PIE;
770 tmp &= ~RTC_AIE;
771 tmp &= ~RTC_UIE;
772 CMOS_WRITE(tmp, RTC_CONTROL);
773 CMOS_READ(RTC_INTR_FLAGS);
774 }
775 if (rtc_status & RTC_TIMER_ON) {
776 rtc_status &= ~RTC_TIMER_ON;
777 del_timer(&rtc_irq_timer);
778 }
779 spin_unlock_irq(&rtc_lock);
780
781 no_irq:
782 #endif
783
784 spin_lock_irq(&rtc_lock);
785 rtc_irq_data = 0;
786 rtc_status &= ~RTC_IS_OPEN;
787 spin_unlock_irq(&rtc_lock);
788
789 return 0;
790 }
791
792 #ifdef RTC_IRQ
rtc_poll(struct file * file,poll_table * wait)793 static unsigned int rtc_poll(struct file *file, poll_table *wait)
794 {
795 unsigned long l;
796
797 if (rtc_has_irq == 0)
798 return 0;
799
800 poll_wait(file, &rtc_wait, wait);
801
802 spin_lock_irq(&rtc_lock);
803 l = rtc_irq_data;
804 spin_unlock_irq(&rtc_lock);
805
806 if (l != 0)
807 return POLLIN | POLLRDNORM;
808 return 0;
809 }
810 #endif
811
rtc_register(rtc_task_t * task)812 int rtc_register(rtc_task_t *task)
813 {
814 #ifndef RTC_IRQ
815 return -EIO;
816 #else
817 if (task == NULL || task->func == NULL)
818 return -EINVAL;
819 spin_lock_irq(&rtc_lock);
820 if (rtc_status & RTC_IS_OPEN) {
821 spin_unlock_irq(&rtc_lock);
822 return -EBUSY;
823 }
824 spin_lock(&rtc_task_lock);
825 if (rtc_callback) {
826 spin_unlock(&rtc_task_lock);
827 spin_unlock_irq(&rtc_lock);
828 return -EBUSY;
829 }
830 rtc_status |= RTC_IS_OPEN;
831 rtc_callback = task;
832 spin_unlock(&rtc_task_lock);
833 spin_unlock_irq(&rtc_lock);
834 return 0;
835 #endif
836 }
837 EXPORT_SYMBOL(rtc_register);
838
rtc_unregister(rtc_task_t * task)839 int rtc_unregister(rtc_task_t *task)
840 {
841 #ifndef RTC_IRQ
842 return -EIO;
843 #else
844 unsigned char tmp;
845
846 spin_lock_irq(&rtc_lock);
847 spin_lock(&rtc_task_lock);
848 if (rtc_callback != task) {
849 spin_unlock(&rtc_task_lock);
850 spin_unlock_irq(&rtc_lock);
851 return -ENXIO;
852 }
853 rtc_callback = NULL;
854
855 /* disable controls */
856 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
857 tmp = CMOS_READ(RTC_CONTROL);
858 tmp &= ~RTC_PIE;
859 tmp &= ~RTC_AIE;
860 tmp &= ~RTC_UIE;
861 CMOS_WRITE(tmp, RTC_CONTROL);
862 CMOS_READ(RTC_INTR_FLAGS);
863 }
864 if (rtc_status & RTC_TIMER_ON) {
865 rtc_status &= ~RTC_TIMER_ON;
866 del_timer(&rtc_irq_timer);
867 }
868 rtc_status &= ~RTC_IS_OPEN;
869 spin_unlock(&rtc_task_lock);
870 spin_unlock_irq(&rtc_lock);
871 return 0;
872 #endif
873 }
874 EXPORT_SYMBOL(rtc_unregister);
875
rtc_control(rtc_task_t * task,unsigned int cmd,unsigned long arg)876 int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
877 {
878 #ifndef RTC_IRQ
879 return -EIO;
880 #else
881 unsigned long flags;
882 if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET)
883 return -EINVAL;
884 spin_lock_irqsave(&rtc_task_lock, flags);
885 if (rtc_callback != task) {
886 spin_unlock_irqrestore(&rtc_task_lock, flags);
887 return -ENXIO;
888 }
889 spin_unlock_irqrestore(&rtc_task_lock, flags);
890 return rtc_do_ioctl(cmd, arg, 1);
891 #endif
892 }
893 EXPORT_SYMBOL(rtc_control);
894
895 /*
896 * The various file operations we support.
897 */
898
899 static const struct file_operations rtc_fops = {
900 .owner = THIS_MODULE,
901 .llseek = no_llseek,
902 .read = rtc_read,
903 #ifdef RTC_IRQ
904 .poll = rtc_poll,
905 #endif
906 .unlocked_ioctl = rtc_ioctl,
907 .open = rtc_open,
908 .release = rtc_release,
909 .fasync = rtc_fasync,
910 };
911
912 static struct miscdevice rtc_dev = {
913 .minor = RTC_MINOR,
914 .name = "rtc",
915 .fops = &rtc_fops,
916 };
917
918 #ifdef CONFIG_PROC_FS
919 static const struct file_operations rtc_proc_fops = {
920 .owner = THIS_MODULE,
921 .open = rtc_proc_open,
922 .read = seq_read,
923 .llseek = seq_lseek,
924 .release = single_release,
925 };
926 #endif
927
928 static resource_size_t rtc_size;
929
rtc_request_region(resource_size_t size)930 static struct resource * __init rtc_request_region(resource_size_t size)
931 {
932 struct resource *r;
933
934 if (RTC_IOMAPPED)
935 r = request_region(RTC_PORT(0), size, "rtc");
936 else
937 r = request_mem_region(RTC_PORT(0), size, "rtc");
938
939 if (r)
940 rtc_size = size;
941
942 return r;
943 }
944
rtc_release_region(void)945 static void rtc_release_region(void)
946 {
947 if (RTC_IOMAPPED)
948 release_region(RTC_PORT(0), rtc_size);
949 else
950 release_mem_region(RTC_PORT(0), rtc_size);
951 }
952
rtc_init(void)953 static int __init rtc_init(void)
954 {
955 #ifdef CONFIG_PROC_FS
956 struct proc_dir_entry *ent;
957 #endif
958 #if defined(__alpha__) || defined(__mips__)
959 unsigned int year, ctrl;
960 char *guess = NULL;
961 #endif
962 #ifdef CONFIG_SPARC32
963 struct device_node *ebus_dp;
964 struct platform_device *op;
965 #else
966 void *r;
967 #ifdef RTC_IRQ
968 irq_handler_t rtc_int_handler_ptr;
969 #endif
970 #endif
971
972 #ifdef CONFIG_SPARC32
973 for_each_node_by_name(ebus_dp, "ebus") {
974 struct device_node *dp;
975 for (dp = ebus_dp; dp; dp = dp->sibling) {
976 if (!strcmp(dp->name, "rtc")) {
977 op = of_find_device_by_node(dp);
978 if (op) {
979 rtc_port = op->resource[0].start;
980 rtc_irq = op->irqs[0];
981 goto found;
982 }
983 }
984 }
985 }
986 rtc_has_irq = 0;
987 printk(KERN_ERR "rtc_init: no PC rtc found\n");
988 return -EIO;
989
990 found:
991 if (!rtc_irq) {
992 rtc_has_irq = 0;
993 goto no_irq;
994 }
995
996 /*
997 * XXX Interrupt pin #7 in Espresso is shared between RTC and
998 * PCI Slot 2 INTA# (and some INTx# in Slot 1).
999 */
1000 if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc",
1001 (void *)&rtc_port)) {
1002 rtc_has_irq = 0;
1003 printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
1004 return -EIO;
1005 }
1006 no_irq:
1007 #else
1008 r = rtc_request_region(RTC_IO_EXTENT);
1009
1010 /*
1011 * If we've already requested a smaller range (for example, because
1012 * PNPBIOS or ACPI told us how the device is configured), the request
1013 * above might fail because it's too big.
1014 *
1015 * If so, request just the range we actually use.
1016 */
1017 if (!r)
1018 r = rtc_request_region(RTC_IO_EXTENT_USED);
1019 if (!r) {
1020 #ifdef RTC_IRQ
1021 rtc_has_irq = 0;
1022 #endif
1023 printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
1024 (long)(RTC_PORT(0)));
1025 return -EIO;
1026 }
1027
1028 #ifdef RTC_IRQ
1029 if (is_hpet_enabled()) {
1030 int err;
1031
1032 rtc_int_handler_ptr = hpet_rtc_interrupt;
1033 err = hpet_register_irq_handler(rtc_interrupt);
1034 if (err != 0) {
1035 printk(KERN_WARNING "hpet_register_irq_handler failed "
1036 "in rtc_init().");
1037 return err;
1038 }
1039 } else {
1040 rtc_int_handler_ptr = rtc_interrupt;
1041 }
1042
1043 if (request_irq(RTC_IRQ, rtc_int_handler_ptr, IRQF_DISABLED,
1044 "rtc", NULL)) {
1045 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
1046 rtc_has_irq = 0;
1047 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
1048 rtc_release_region();
1049
1050 return -EIO;
1051 }
1052 hpet_rtc_timer_init();
1053
1054 #endif
1055
1056 #endif /* CONFIG_SPARC32 vs. others */
1057
1058 if (misc_register(&rtc_dev)) {
1059 #ifdef RTC_IRQ
1060 free_irq(RTC_IRQ, NULL);
1061 hpet_unregister_irq_handler(rtc_interrupt);
1062 rtc_has_irq = 0;
1063 #endif
1064 rtc_release_region();
1065 return -ENODEV;
1066 }
1067
1068 #ifdef CONFIG_PROC_FS
1069 ent = proc_create("driver/rtc", 0, NULL, &rtc_proc_fops);
1070 if (!ent)
1071 printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
1072 #endif
1073
1074 #if defined(__alpha__) || defined(__mips__)
1075 rtc_freq = HZ;
1076
1077 /* Each operating system on an Alpha uses its own epoch.
1078 Let's try to guess which one we are using now. */
1079
1080 if (rtc_is_updating() != 0)
1081 msleep(20);
1082
1083 spin_lock_irq(&rtc_lock);
1084 year = CMOS_READ(RTC_YEAR);
1085 ctrl = CMOS_READ(RTC_CONTROL);
1086 spin_unlock_irq(&rtc_lock);
1087
1088 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1089 year = bcd2bin(year); /* This should never happen... */
1090
1091 if (year < 20) {
1092 epoch = 2000;
1093 guess = "SRM (post-2000)";
1094 } else if (year >= 20 && year < 48) {
1095 epoch = 1980;
1096 guess = "ARC console";
1097 } else if (year >= 48 && year < 72) {
1098 epoch = 1952;
1099 guess = "Digital UNIX";
1100 #if defined(__mips__)
1101 } else if (year >= 72 && year < 74) {
1102 epoch = 2000;
1103 guess = "Digital DECstation";
1104 #else
1105 } else if (year >= 70) {
1106 epoch = 1900;
1107 guess = "Standard PC (1900)";
1108 #endif
1109 }
1110 if (guess)
1111 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n",
1112 guess, epoch);
1113 #endif
1114 #ifdef RTC_IRQ
1115 if (rtc_has_irq == 0)
1116 goto no_irq2;
1117
1118 spin_lock_irq(&rtc_lock);
1119 rtc_freq = 1024;
1120 if (!hpet_set_periodic_freq(rtc_freq)) {
1121 /*
1122 * Initialize periodic frequency to CMOS reset default,
1123 * which is 1024Hz
1124 */
1125 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06),
1126 RTC_FREQ_SELECT);
1127 }
1128 spin_unlock_irq(&rtc_lock);
1129 no_irq2:
1130 #endif
1131
1132 (void) init_sysctl();
1133
1134 printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
1135
1136 return 0;
1137 }
1138
rtc_exit(void)1139 static void __exit rtc_exit(void)
1140 {
1141 cleanup_sysctl();
1142 remove_proc_entry("driver/rtc", NULL);
1143 misc_deregister(&rtc_dev);
1144
1145 #ifdef CONFIG_SPARC32
1146 if (rtc_has_irq)
1147 free_irq(rtc_irq, &rtc_port);
1148 #else
1149 rtc_release_region();
1150 #ifdef RTC_IRQ
1151 if (rtc_has_irq) {
1152 free_irq(RTC_IRQ, NULL);
1153 hpet_unregister_irq_handler(hpet_rtc_interrupt);
1154 }
1155 #endif
1156 #endif /* CONFIG_SPARC32 */
1157 }
1158
1159 module_init(rtc_init);
1160 module_exit(rtc_exit);
1161
1162 #ifdef RTC_IRQ
1163 /*
1164 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1165 * (usually during an IDE disk interrupt, with IRQ unmasking off)
1166 * Since the interrupt handler doesn't get called, the IRQ status
1167 * byte doesn't get read, and the RTC stops generating interrupts.
1168 * A timer is set, and will call this function if/when that happens.
1169 * To get it out of this stalled state, we just read the status.
1170 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1171 * (You *really* shouldn't be trying to use a non-realtime system
1172 * for something that requires a steady > 1KHz signal anyways.)
1173 */
1174
rtc_dropped_irq(unsigned long data)1175 static void rtc_dropped_irq(unsigned long data)
1176 {
1177 unsigned long freq;
1178
1179 spin_lock_irq(&rtc_lock);
1180
1181 if (hpet_rtc_dropped_irq()) {
1182 spin_unlock_irq(&rtc_lock);
1183 return;
1184 }
1185
1186 /* Just in case someone disabled the timer from behind our back... */
1187 if (rtc_status & RTC_TIMER_ON)
1188 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
1189
1190 rtc_irq_data += ((rtc_freq/HZ)<<8);
1191 rtc_irq_data &= ~0xff;
1192 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */
1193
1194 freq = rtc_freq;
1195
1196 spin_unlock_irq(&rtc_lock);
1197
1198 printk_ratelimited(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
1199 freq);
1200
1201 /* Now we have new data */
1202 wake_up_interruptible(&rtc_wait);
1203
1204 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
1205 }
1206 #endif
1207
1208 #ifdef CONFIG_PROC_FS
1209 /*
1210 * Info exported via "/proc/driver/rtc".
1211 */
1212
rtc_proc_show(struct seq_file * seq,void * v)1213 static int rtc_proc_show(struct seq_file *seq, void *v)
1214 {
1215 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1216 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1217 struct rtc_time tm;
1218 unsigned char batt, ctrl;
1219 unsigned long freq;
1220
1221 spin_lock_irq(&rtc_lock);
1222 batt = CMOS_READ(RTC_VALID) & RTC_VRT;
1223 ctrl = CMOS_READ(RTC_CONTROL);
1224 freq = rtc_freq;
1225 spin_unlock_irq(&rtc_lock);
1226
1227
1228 rtc_get_rtc_time(&tm);
1229
1230 /*
1231 * There is no way to tell if the luser has the RTC set for local
1232 * time or for Universal Standard Time (GMT). Probably local though.
1233 */
1234 seq_printf(seq,
1235 "rtc_time\t: %02d:%02d:%02d\n"
1236 "rtc_date\t: %04d-%02d-%02d\n"
1237 "rtc_epoch\t: %04lu\n",
1238 tm.tm_hour, tm.tm_min, tm.tm_sec,
1239 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
1240
1241 get_rtc_alm_time(&tm);
1242
1243 /*
1244 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1245 * match any value for that particular field. Values that are
1246 * greater than a valid time, but less than 0xc0 shouldn't appear.
1247 */
1248 seq_puts(seq, "alarm\t\t: ");
1249 if (tm.tm_hour <= 24)
1250 seq_printf(seq, "%02d:", tm.tm_hour);
1251 else
1252 seq_puts(seq, "**:");
1253
1254 if (tm.tm_min <= 59)
1255 seq_printf(seq, "%02d:", tm.tm_min);
1256 else
1257 seq_puts(seq, "**:");
1258
1259 if (tm.tm_sec <= 59)
1260 seq_printf(seq, "%02d\n", tm.tm_sec);
1261 else
1262 seq_puts(seq, "**\n");
1263
1264 seq_printf(seq,
1265 "DST_enable\t: %s\n"
1266 "BCD\t\t: %s\n"
1267 "24hr\t\t: %s\n"
1268 "square_wave\t: %s\n"
1269 "alarm_IRQ\t: %s\n"
1270 "update_IRQ\t: %s\n"
1271 "periodic_IRQ\t: %s\n"
1272 "periodic_freq\t: %ld\n"
1273 "batt_status\t: %s\n",
1274 YN(RTC_DST_EN),
1275 NY(RTC_DM_BINARY),
1276 YN(RTC_24H),
1277 YN(RTC_SQWE),
1278 YN(RTC_AIE),
1279 YN(RTC_UIE),
1280 YN(RTC_PIE),
1281 freq,
1282 batt ? "okay" : "dead");
1283
1284 return 0;
1285 #undef YN
1286 #undef NY
1287 }
1288
rtc_proc_open(struct inode * inode,struct file * file)1289 static int rtc_proc_open(struct inode *inode, struct file *file)
1290 {
1291 return single_open(file, rtc_proc_show, NULL);
1292 }
1293 #endif
1294
rtc_get_rtc_time(struct rtc_time * rtc_tm)1295 static void rtc_get_rtc_time(struct rtc_time *rtc_tm)
1296 {
1297 unsigned long uip_watchdog = jiffies, flags;
1298 unsigned char ctrl;
1299 #ifdef CONFIG_MACH_DECSTATION
1300 unsigned int real_year;
1301 #endif
1302
1303 /*
1304 * read RTC once any update in progress is done. The update
1305 * can take just over 2ms. We wait 20ms. There is no need to
1306 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1307 * If you need to know *exactly* when a second has started, enable
1308 * periodic update complete interrupts, (via ioctl) and then
1309 * immediately read /dev/rtc which will block until you get the IRQ.
1310 * Once the read clears, read the RTC time (again via ioctl). Easy.
1311 */
1312
1313 while (rtc_is_updating() != 0 &&
1314 time_before(jiffies, uip_watchdog + 2*HZ/100))
1315 cpu_relax();
1316
1317 /*
1318 * Only the values that we read from the RTC are set. We leave
1319 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1320 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1321 * only updated by the RTC when initially set to a non-zero value.
1322 */
1323 spin_lock_irqsave(&rtc_lock, flags);
1324 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
1325 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
1326 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
1327 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
1328 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
1329 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
1330 /* Only set from 2.6.16 onwards */
1331 rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);
1332
1333 #ifdef CONFIG_MACH_DECSTATION
1334 real_year = CMOS_READ(RTC_DEC_YEAR);
1335 #endif
1336 ctrl = CMOS_READ(RTC_CONTROL);
1337 spin_unlock_irqrestore(&rtc_lock, flags);
1338
1339 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1340 rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
1341 rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
1342 rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
1343 rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
1344 rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
1345 rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
1346 rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
1347 }
1348
1349 #ifdef CONFIG_MACH_DECSTATION
1350 rtc_tm->tm_year += real_year - 72;
1351 #endif
1352
1353 /*
1354 * Account for differences between how the RTC uses the values
1355 * and how they are defined in a struct rtc_time;
1356 */
1357 rtc_tm->tm_year += epoch - 1900;
1358 if (rtc_tm->tm_year <= 69)
1359 rtc_tm->tm_year += 100;
1360
1361 rtc_tm->tm_mon--;
1362 }
1363
get_rtc_alm_time(struct rtc_time * alm_tm)1364 static void get_rtc_alm_time(struct rtc_time *alm_tm)
1365 {
1366 unsigned char ctrl;
1367
1368 /*
1369 * Only the values that we read from the RTC are set. That
1370 * means only tm_hour, tm_min, and tm_sec.
1371 */
1372 spin_lock_irq(&rtc_lock);
1373 alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
1374 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
1375 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
1376 ctrl = CMOS_READ(RTC_CONTROL);
1377 spin_unlock_irq(&rtc_lock);
1378
1379 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1380 alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
1381 alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
1382 alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
1383 }
1384 }
1385
1386 #ifdef RTC_IRQ
1387 /*
1388 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1389 * Rumour has it that if you frob the interrupt enable/disable
1390 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1391 * ensure you actually start getting interrupts. Probably for
1392 * compatibility with older/broken chipset RTC implementations.
1393 * We also clear out any old irq data after an ioctl() that
1394 * meddles with the interrupt enable/disable bits.
1395 */
1396
mask_rtc_irq_bit_locked(unsigned char bit)1397 static void mask_rtc_irq_bit_locked(unsigned char bit)
1398 {
1399 unsigned char val;
1400
1401 if (hpet_mask_rtc_irq_bit(bit))
1402 return;
1403 val = CMOS_READ(RTC_CONTROL);
1404 val &= ~bit;
1405 CMOS_WRITE(val, RTC_CONTROL);
1406 CMOS_READ(RTC_INTR_FLAGS);
1407
1408 rtc_irq_data = 0;
1409 }
1410
set_rtc_irq_bit_locked(unsigned char bit)1411 static void set_rtc_irq_bit_locked(unsigned char bit)
1412 {
1413 unsigned char val;
1414
1415 if (hpet_set_rtc_irq_bit(bit))
1416 return;
1417 val = CMOS_READ(RTC_CONTROL);
1418 val |= bit;
1419 CMOS_WRITE(val, RTC_CONTROL);
1420 CMOS_READ(RTC_INTR_FLAGS);
1421
1422 rtc_irq_data = 0;
1423 }
1424 #endif
1425
1426 MODULE_AUTHOR("Paul Gortmaker");
1427 MODULE_LICENSE("GPL");
1428 MODULE_ALIAS_MISCDEV(RTC_MINOR);
1429