2 * Real Time Clock interface for Linux
4 * Copyright (C) 1996 Paul Gortmaker
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.
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.
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.
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.
28 * Based on other minimal char device drivers, like Alan's
29 * watchdog, Ted's random, etc. etc.
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
53 #define RTC_VERSION "1.12ac"
56 * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
57 * interrupts disabled. Due to the index-port/data-port (0x70/0x71)
58 * design of the RTC, we don't want two different things trying to
59 * get to it at once. (e.g. the periodic 11 min sync from time.c vs.
63 #include <linux/interrupt.h>
64 #include <linux/module.h>
65 #include <linux/kernel.h>
66 #include <linux/types.h>
67 #include <linux/miscdevice.h>
68 #include <linux/ioport.h>
69 #include <linux/fcntl.h>
70 #include <linux/mc146818rtc.h>
71 #include <linux/init.h>
72 #include <linux/poll.h>
73 #include <linux/proc_fs.h>
74 #include <linux/seq_file.h>
75 #include <linux/spinlock.h>
76 #include <linux/sysctl.h>
77 #include <linux/wait.h>
78 #include <linux/bcd.h>
79 #include <linux/delay.h>
81 #include <asm/current.h>
82 #include <asm/uaccess.h>
83 #include <asm/system.h>
90 #include <linux/pci.h>
96 static unsigned long rtc_port
;
97 static int rtc_irq
= PCI_IRQ_NONE
;
100 #ifdef CONFIG_HPET_RTC_IRQ
105 static int rtc_has_irq
= 1;
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
117 static irqreturn_t
hpet_rtc_interrupt(int irq
, void *dev_id
)
123 extern irqreturn_t
hpet_rtc_interrupt(int irq
, void *dev_id
);
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
133 static struct fasync_struct
*rtc_async_queue
;
135 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait
);
138 static void rtc_dropped_irq(unsigned long data
);
140 static DEFINE_TIMER(rtc_irq_timer
, rtc_dropped_irq
, 0, 0);
143 static ssize_t
rtc_read(struct file
*file
, char __user
*buf
,
144 size_t count
, loff_t
*ppos
);
146 static int rtc_ioctl(struct inode
*inode
, struct file
*file
,
147 unsigned int cmd
, unsigned long arg
);
150 static unsigned int rtc_poll(struct file
*file
, poll_table
*wait
);
153 static void get_rtc_alm_time (struct rtc_time
*alm_tm
);
155 static void set_rtc_irq_bit_locked(unsigned char bit
);
156 static void mask_rtc_irq_bit_locked(unsigned char bit
);
158 static inline void set_rtc_irq_bit(unsigned char bit
)
160 spin_lock_irq(&rtc_lock
);
161 set_rtc_irq_bit_locked(bit
);
162 spin_unlock_irq(&rtc_lock
);
165 static void mask_rtc_irq_bit(unsigned char bit
)
167 spin_lock_irq(&rtc_lock
);
168 mask_rtc_irq_bit_locked(bit
);
169 spin_unlock_irq(&rtc_lock
);
173 #ifdef CONFIG_PROC_FS
174 static int rtc_proc_open(struct inode
*inode
, struct file
*file
);
178 * Bits in rtc_status. (6 bits of room for future expansion)
181 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
182 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
185 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
186 * protected by the big kernel lock. However, ioctl can still disable the timer
187 * 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)
191 static unsigned long rtc_status
= 0; /* bitmapped status byte. */
192 static unsigned long rtc_freq
= 0; /* Current periodic IRQ rate */
193 static unsigned long rtc_irq_data
= 0; /* our output to the world */
194 static unsigned long rtc_max_user_freq
= 64; /* > this, need CAP_SYS_RESOURCE */
198 * rtc_task_lock nests inside rtc_lock.
200 static DEFINE_SPINLOCK(rtc_task_lock
);
201 static rtc_task_t
*rtc_callback
= NULL
;
205 * If this driver ever becomes modularised, it will be really nice
206 * to make the epoch retain its value across module reload...
209 static unsigned long epoch
= 1900; /* year corresponding to 0x00 */
211 static const unsigned char days_in_mo
[] =
212 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
215 * Returns true if a clock update is in progress
217 static inline unsigned char rtc_is_updating(void)
222 spin_lock_irqsave(&rtc_lock
, flags
);
223 uip
= (CMOS_READ(RTC_FREQ_SELECT
) & RTC_UIP
);
224 spin_unlock_irqrestore(&rtc_lock
, flags
);
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.)
239 irqreturn_t
rtc_interrupt(int irq
, void *dev_id
)
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.
248 spin_lock (&rtc_lock
);
249 rtc_irq_data
+= 0x100;
250 rtc_irq_data
&= ~0xff;
251 if (is_hpet_enabled()) {
253 * In this case it is HPET RTC interrupt handler
254 * calling us, with the interrupt information
255 * passed as arg1, instead of irq.
257 rtc_irq_data
|= (unsigned long)irq
& 0xF0;
259 rtc_irq_data
|= (CMOS_READ(RTC_INTR_FLAGS
) & 0xF0);
262 if (rtc_status
& RTC_TIMER_ON
)
263 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100);
265 spin_unlock (&rtc_lock
);
267 /* Now do the rest of the actions */
268 spin_lock(&rtc_task_lock
);
270 rtc_callback
->func(rtc_callback
->private_data
);
271 spin_unlock(&rtc_task_lock
);
272 wake_up_interruptible(&rtc_wait
);
274 kill_fasync (&rtc_async_queue
, SIGIO
, POLL_IN
);
281 * sysctl-tuning infrastructure.
283 static ctl_table rtc_table
[] = {
286 .procname
= "max-user-freq",
287 .data
= &rtc_max_user_freq
,
288 .maxlen
= sizeof(int),
290 .proc_handler
= &proc_dointvec
,
295 static ctl_table rtc_root
[] = {
306 static ctl_table dev_root
[] = {
317 static struct ctl_table_header
*sysctl_header
;
319 static int __init
init_sysctl(void)
321 sysctl_header
= register_sysctl_table(dev_root
, 0);
325 static void __exit
cleanup_sysctl(void)
327 unregister_sysctl_table(sysctl_header
);
331 * Now all the various file operations that we export.
334 static ssize_t
rtc_read(struct file
*file
, char __user
*buf
,
335 size_t count
, loff_t
*ppos
)
340 DECLARE_WAITQUEUE(wait
, current
);
344 if (rtc_has_irq
== 0)
348 * Historically this function used to assume that sizeof(unsigned long)
349 * is the same in userspace and kernelspace. This lead to problems
350 * for configurations with multiple ABIs such a the MIPS o32 and 64
351 * ABIs supported on the same kernel. So now we support read of both
352 * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
355 if (count
!= sizeof(unsigned int) && count
!= sizeof(unsigned long))
358 add_wait_queue(&rtc_wait
, &wait
);
361 /* First make it right. Then make it fast. Putting this whole
362 * block within the parentheses of a while would be too
363 * confusing. And no, xchg() is not the answer. */
365 __set_current_state(TASK_INTERRUPTIBLE
);
367 spin_lock_irq (&rtc_lock
);
370 spin_unlock_irq (&rtc_lock
);
375 if (file
->f_flags
& O_NONBLOCK
) {
379 if (signal_pending(current
)) {
380 retval
= -ERESTARTSYS
;
386 if (count
== sizeof(unsigned int))
387 retval
= put_user(data
, (unsigned int __user
*)buf
) ?: sizeof(int);
389 retval
= put_user(data
, (unsigned long __user
*)buf
) ?: sizeof(long);
393 current
->state
= TASK_RUNNING
;
394 remove_wait_queue(&rtc_wait
, &wait
);
400 static int rtc_do_ioctl(unsigned int cmd
, unsigned long arg
, int kernel
)
402 struct rtc_time wtime
;
405 if (rtc_has_irq
== 0) {
422 case RTC_AIE_OFF
: /* Mask alarm int. enab. bit */
424 mask_rtc_irq_bit(RTC_AIE
);
427 case RTC_AIE_ON
: /* Allow alarm interrupts. */
429 set_rtc_irq_bit(RTC_AIE
);
432 case RTC_PIE_OFF
: /* Mask periodic int. enab. bit */
434 unsigned long flags
; /* can be called from isr via rtc_control() */
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
);
441 spin_unlock_irqrestore (&rtc_lock
, flags
);
444 case RTC_PIE_ON
: /* Allow periodic ints */
446 unsigned long flags
; /* can be called from isr via rtc_control() */
448 * We don't really want Joe User enabling more
449 * than 64Hz of interrupts on a multi-user machine.
451 if (!kernel
&& (rtc_freq
> rtc_max_user_freq
) &&
452 (!capable(CAP_SYS_RESOURCE
)))
455 spin_lock_irqsave (&rtc_lock
, flags
);
456 if (!(rtc_status
& RTC_TIMER_ON
)) {
457 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+
459 rtc_status
|= RTC_TIMER_ON
;
461 set_rtc_irq_bit_locked(RTC_PIE
);
462 spin_unlock_irqrestore (&rtc_lock
, flags
);
465 case RTC_UIE_OFF
: /* Mask ints from RTC updates. */
467 mask_rtc_irq_bit(RTC_UIE
);
470 case RTC_UIE_ON
: /* Allow ints for RTC updates. */
472 set_rtc_irq_bit(RTC_UIE
);
476 case RTC_ALM_READ
: /* Read the present alarm time */
479 * This returns a struct rtc_time. Reading >= 0xc0
480 * means "don't care" or "match all". Only the tm_hour,
481 * tm_min, and tm_sec values are filled in.
483 memset(&wtime
, 0, sizeof(struct rtc_time
));
484 get_rtc_alm_time(&wtime
);
487 case RTC_ALM_SET
: /* Store a time into the alarm */
490 * This expects a struct rtc_time. Writing 0xff means
491 * "don't care" or "match all". Only the tm_hour,
492 * tm_min and tm_sec are used.
494 unsigned char hrs
, min
, sec
;
495 struct rtc_time alm_tm
;
497 if (copy_from_user(&alm_tm
, (struct rtc_time __user
*)arg
,
498 sizeof(struct rtc_time
)))
501 hrs
= alm_tm
.tm_hour
;
505 spin_lock_irq(&rtc_lock
);
506 if (hpet_set_alarm_time(hrs
, min
, sec
)) {
508 * Fallthru and set alarm time in CMOS too,
509 * so that we will get proper value in RTC_ALM_READ
512 if (!(CMOS_READ(RTC_CONTROL
) & RTC_DM_BINARY
) ||
515 if (sec
< 60) BIN_TO_BCD(sec
);
518 if (min
< 60) BIN_TO_BCD(min
);
521 if (hrs
< 24) BIN_TO_BCD(hrs
);
524 CMOS_WRITE(hrs
, RTC_HOURS_ALARM
);
525 CMOS_WRITE(min
, RTC_MINUTES_ALARM
);
526 CMOS_WRITE(sec
, RTC_SECONDS_ALARM
);
527 spin_unlock_irq(&rtc_lock
);
531 case RTC_RD_TIME
: /* Read the time/date from RTC */
533 memset(&wtime
, 0, sizeof(struct rtc_time
));
534 rtc_get_rtc_time(&wtime
);
537 case RTC_SET_TIME
: /* Set the RTC */
539 struct rtc_time rtc_tm
;
540 unsigned char mon
, day
, hrs
, min
, sec
, leap_yr
;
541 unsigned char save_control
, save_freq_select
;
543 #ifdef CONFIG_MACH_DECSTATION
544 unsigned int real_yrs
;
547 if (!capable(CAP_SYS_TIME
))
550 if (copy_from_user(&rtc_tm
, (struct rtc_time __user
*)arg
,
551 sizeof(struct rtc_time
)))
554 yrs
= rtc_tm
.tm_year
+ 1900;
555 mon
= rtc_tm
.tm_mon
+ 1; /* tm_mon starts at zero */
556 day
= rtc_tm
.tm_mday
;
557 hrs
= rtc_tm
.tm_hour
;
564 leap_yr
= ((!(yrs
% 4) && (yrs
% 100)) || !(yrs
% 400));
566 if ((mon
> 12) || (day
== 0))
569 if (day
> (days_in_mo
[mon
] + ((mon
== 2) && leap_yr
)))
572 if ((hrs
>= 24) || (min
>= 60) || (sec
>= 60))
575 if ((yrs
-= epoch
) > 255) /* They are unsigned */
578 spin_lock_irq(&rtc_lock
);
579 #ifdef CONFIG_MACH_DECSTATION
584 * We want to keep the year set to 73 until March
585 * for non-leap years, so that Feb, 29th is handled
588 if (!leap_yr
&& mon
< 3) {
593 /* These limits and adjustments are independent of
594 * whether the chip is in binary mode or not.
597 spin_unlock_irq(&rtc_lock
);
603 if (!(CMOS_READ(RTC_CONTROL
) & RTC_DM_BINARY
)
613 save_control
= CMOS_READ(RTC_CONTROL
);
614 CMOS_WRITE((save_control
|RTC_SET
), RTC_CONTROL
);
615 save_freq_select
= CMOS_READ(RTC_FREQ_SELECT
);
616 CMOS_WRITE((save_freq_select
|RTC_DIV_RESET2
), RTC_FREQ_SELECT
);
618 #ifdef CONFIG_MACH_DECSTATION
619 CMOS_WRITE(real_yrs
, RTC_DEC_YEAR
);
621 CMOS_WRITE(yrs
, RTC_YEAR
);
622 CMOS_WRITE(mon
, RTC_MONTH
);
623 CMOS_WRITE(day
, RTC_DAY_OF_MONTH
);
624 CMOS_WRITE(hrs
, RTC_HOURS
);
625 CMOS_WRITE(min
, RTC_MINUTES
);
626 CMOS_WRITE(sec
, RTC_SECONDS
);
628 CMOS_WRITE(save_control
, RTC_CONTROL
);
629 CMOS_WRITE(save_freq_select
, RTC_FREQ_SELECT
);
631 spin_unlock_irq(&rtc_lock
);
635 case RTC_IRQP_READ
: /* Read the periodic IRQ rate. */
637 return put_user(rtc_freq
, (unsigned long __user
*)arg
);
639 case RTC_IRQP_SET
: /* Set periodic IRQ rate. */
643 unsigned long flags
; /* can be called from isr via rtc_control() */
646 * The max we can do is 8192Hz.
648 if ((arg
< 2) || (arg
> 8192))
651 * We don't really want Joe User generating more
652 * than 64Hz of interrupts on a multi-user machine.
654 if (!kernel
&& (arg
> rtc_max_user_freq
) && (!capable(CAP_SYS_RESOURCE
)))
657 while (arg
> (1<<tmp
))
661 * Check that the input was really a power of 2.
666 spin_lock_irqsave(&rtc_lock
, flags
);
667 if (hpet_set_periodic_freq(arg
)) {
668 spin_unlock_irqrestore(&rtc_lock
, flags
);
673 val
= CMOS_READ(RTC_FREQ_SELECT
) & 0xf0;
675 CMOS_WRITE(val
, RTC_FREQ_SELECT
);
676 spin_unlock_irqrestore(&rtc_lock
, flags
);
680 case RTC_EPOCH_READ
: /* Read the epoch. */
682 return put_user (epoch
, (unsigned long __user
*)arg
);
684 case RTC_EPOCH_SET
: /* Set the epoch. */
687 * There were no RTC clocks before 1900.
692 if (!capable(CAP_SYS_TIME
))
701 return copy_to_user((void __user
*)arg
, &wtime
, sizeof wtime
) ? -EFAULT
: 0;
704 static int rtc_ioctl(struct inode
*inode
, struct file
*file
, unsigned int cmd
,
707 return rtc_do_ioctl(cmd
, arg
, 0);
711 * We enforce only one user at a time here with the open/close.
712 * Also clear the previous interrupt data on an open, and clean
713 * up things on a close.
716 /* We use rtc_lock to protect against concurrent opens. So the BKL is not
717 * needed here. Or anywhere else in this driver. */
718 static int rtc_open(struct inode
*inode
, struct file
*file
)
720 spin_lock_irq (&rtc_lock
);
722 if(rtc_status
& RTC_IS_OPEN
)
725 rtc_status
|= RTC_IS_OPEN
;
728 spin_unlock_irq (&rtc_lock
);
732 spin_unlock_irq (&rtc_lock
);
736 static int rtc_fasync (int fd
, struct file
*filp
, int on
)
739 return fasync_helper (fd
, filp
, on
, &rtc_async_queue
);
742 static int rtc_release(struct inode
*inode
, struct file
*file
)
747 if (rtc_has_irq
== 0)
751 * Turn off all interrupts once the device is no longer
752 * in use, and clear the data.
755 spin_lock_irq(&rtc_lock
);
756 if (!hpet_mask_rtc_irq_bit(RTC_PIE
| RTC_AIE
| RTC_UIE
)) {
757 tmp
= CMOS_READ(RTC_CONTROL
);
761 CMOS_WRITE(tmp
, RTC_CONTROL
);
762 CMOS_READ(RTC_INTR_FLAGS
);
764 if (rtc_status
& RTC_TIMER_ON
) {
765 rtc_status
&= ~RTC_TIMER_ON
;
766 del_timer(&rtc_irq_timer
);
768 spin_unlock_irq(&rtc_lock
);
770 if (file
->f_flags
& FASYNC
) {
771 rtc_fasync (-1, file
, 0);
776 spin_lock_irq (&rtc_lock
);
778 rtc_status
&= ~RTC_IS_OPEN
;
779 spin_unlock_irq (&rtc_lock
);
784 /* Called without the kernel lock - fine */
785 static unsigned int rtc_poll(struct file
*file
, poll_table
*wait
)
789 if (rtc_has_irq
== 0)
792 poll_wait(file
, &rtc_wait
, wait
);
794 spin_lock_irq (&rtc_lock
);
796 spin_unlock_irq (&rtc_lock
);
799 return POLLIN
| POLLRDNORM
;
808 EXPORT_SYMBOL(rtc_register
);
809 EXPORT_SYMBOL(rtc_unregister
);
810 EXPORT_SYMBOL(rtc_control
);
812 int rtc_register(rtc_task_t
*task
)
817 if (task
== NULL
|| task
->func
== NULL
)
819 spin_lock_irq(&rtc_lock
);
820 if (rtc_status
& RTC_IS_OPEN
) {
821 spin_unlock_irq(&rtc_lock
);
824 spin_lock(&rtc_task_lock
);
826 spin_unlock(&rtc_task_lock
);
827 spin_unlock_irq(&rtc_lock
);
830 rtc_status
|= RTC_IS_OPEN
;
832 spin_unlock(&rtc_task_lock
);
833 spin_unlock_irq(&rtc_lock
);
838 int rtc_unregister(rtc_task_t
*task
)
845 spin_lock_irq(&rtc_lock
);
846 spin_lock(&rtc_task_lock
);
847 if (rtc_callback
!= task
) {
848 spin_unlock(&rtc_task_lock
);
849 spin_unlock_irq(&rtc_lock
);
854 /* disable controls */
855 if (!hpet_mask_rtc_irq_bit(RTC_PIE
| RTC_AIE
| RTC_UIE
)) {
856 tmp
= CMOS_READ(RTC_CONTROL
);
860 CMOS_WRITE(tmp
, RTC_CONTROL
);
861 CMOS_READ(RTC_INTR_FLAGS
);
863 if (rtc_status
& RTC_TIMER_ON
) {
864 rtc_status
&= ~RTC_TIMER_ON
;
865 del_timer(&rtc_irq_timer
);
867 rtc_status
&= ~RTC_IS_OPEN
;
868 spin_unlock(&rtc_task_lock
);
869 spin_unlock_irq(&rtc_lock
);
874 int rtc_control(rtc_task_t
*task
, unsigned int cmd
, unsigned long arg
)
880 if (cmd
!= RTC_PIE_ON
&& cmd
!= RTC_PIE_OFF
&& cmd
!= RTC_IRQP_SET
)
882 spin_lock_irqsave(&rtc_task_lock
, flags
);
883 if (rtc_callback
!= task
) {
884 spin_unlock_irqrestore(&rtc_task_lock
, flags
);
887 spin_unlock_irqrestore(&rtc_task_lock
, flags
);
888 return rtc_do_ioctl(cmd
, arg
, 1);
894 * The various file operations we support.
897 static const struct file_operations rtc_fops
= {
898 .owner
= THIS_MODULE
,
906 .release
= rtc_release
,
907 .fasync
= rtc_fasync
,
910 static struct miscdevice rtc_dev
= {
916 #ifdef CONFIG_PROC_FS
917 static const struct file_operations rtc_proc_fops
= {
918 .owner
= THIS_MODULE
,
919 .open
= rtc_proc_open
,
922 .release
= single_release
,
926 static int __init
rtc_init(void)
928 #ifdef CONFIG_PROC_FS
929 struct proc_dir_entry
*ent
;
931 #if defined(__alpha__) || defined(__mips__)
932 unsigned int year
, ctrl
;
936 struct linux_ebus
*ebus
;
937 struct linux_ebus_device
*edev
;
939 struct sparc_isa_bridge
*isa_br
;
940 struct sparc_isa_device
*isa_dev
;
945 irq_handler_t rtc_int_handler_ptr
;
950 for_each_ebus(ebus
) {
951 for_each_ebusdev(edev
, ebus
) {
952 if(strcmp(edev
->prom_node
->name
, "rtc") == 0) {
953 rtc_port
= edev
->resource
[0].start
;
954 rtc_irq
= edev
->irqs
[0];
960 for_each_isa(isa_br
) {
961 for_each_isadev(isa_dev
, isa_br
) {
962 if (strcmp(isa_dev
->prom_node
->name
, "rtc") == 0) {
963 rtc_port
= isa_dev
->resource
.start
;
964 rtc_irq
= isa_dev
->irq
;
971 printk(KERN_ERR
"rtc_init: no PC rtc found\n");
975 if (rtc_irq
== PCI_IRQ_NONE
) {
981 * XXX Interrupt pin #7 in Espresso is shared between RTC and
982 * PCI Slot 2 INTA# (and some INTx# in Slot 1).
984 if (request_irq(rtc_irq
, rtc_interrupt
, IRQF_SHARED
, "rtc", (void *)&rtc_port
)) {
986 printk(KERN_ERR
"rtc: cannot register IRQ %d\n", rtc_irq
);
992 r
= request_region(RTC_PORT(0), RTC_IO_EXTENT
, "rtc");
994 r
= request_mem_region(RTC_PORT(0), RTC_IO_EXTENT
, "rtc");
999 printk(KERN_ERR
"rtc: I/O resource %lx is not free.\n",
1000 (long)(RTC_PORT(0)));
1005 if (is_hpet_enabled()) {
1006 rtc_int_handler_ptr
= hpet_rtc_interrupt
;
1008 rtc_int_handler_ptr
= rtc_interrupt
;
1011 if(request_irq(RTC_IRQ
, rtc_int_handler_ptr
, IRQF_DISABLED
, "rtc", NULL
)) {
1012 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
1014 printk(KERN_ERR
"rtc: IRQ %d is not free.\n", RTC_IRQ
);
1016 release_region(RTC_PORT(0), RTC_IO_EXTENT
);
1018 release_mem_region(RTC_PORT(0), RTC_IO_EXTENT
);
1021 hpet_rtc_timer_init();
1025 #endif /* __sparc__ vs. others */
1027 if (misc_register(&rtc_dev
)) {
1029 free_irq(RTC_IRQ
, NULL
);
1032 release_region(RTC_PORT(0), RTC_IO_EXTENT
);
1036 #ifdef CONFIG_PROC_FS
1037 ent
= create_proc_entry("driver/rtc", 0, NULL
);
1039 ent
->proc_fops
= &rtc_proc_fops
;
1041 printk(KERN_WARNING
"rtc: Failed to register with procfs.\n");
1044 #if defined(__alpha__) || defined(__mips__)
1047 /* Each operating system on an Alpha uses its own epoch.
1048 Let's try to guess which one we are using now. */
1050 if (rtc_is_updating() != 0)
1053 spin_lock_irq(&rtc_lock
);
1054 year
= CMOS_READ(RTC_YEAR
);
1055 ctrl
= CMOS_READ(RTC_CONTROL
);
1056 spin_unlock_irq(&rtc_lock
);
1058 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1059 BCD_TO_BIN(year
); /* This should never happen... */
1063 guess
= "SRM (post-2000)";
1064 } else if (year
>= 20 && year
< 48) {
1066 guess
= "ARC console";
1067 } else if (year
>= 48 && year
< 72) {
1069 guess
= "Digital UNIX";
1070 #if defined(__mips__)
1071 } else if (year
>= 72 && year
< 74) {
1073 guess
= "Digital DECstation";
1075 } else if (year
>= 70) {
1077 guess
= "Standard PC (1900)";
1081 printk(KERN_INFO
"rtc: %s epoch (%lu) detected\n", guess
, epoch
);
1084 if (rtc_has_irq
== 0)
1087 spin_lock_irq(&rtc_lock
);
1089 if (!hpet_set_periodic_freq(rtc_freq
)) {
1090 /* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
1091 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT
) & 0xF0) | 0x06), RTC_FREQ_SELECT
);
1093 spin_unlock_irq(&rtc_lock
);
1097 (void) init_sysctl();
1099 printk(KERN_INFO
"Real Time Clock Driver v" RTC_VERSION
"\n");
1104 static void __exit
rtc_exit (void)
1107 remove_proc_entry ("driver/rtc", NULL
);
1108 misc_deregister(&rtc_dev
);
1112 free_irq (rtc_irq
, &rtc_port
);
1115 release_region(RTC_PORT(0), RTC_IO_EXTENT
);
1117 release_mem_region(RTC_PORT(0), RTC_IO_EXTENT
);
1120 free_irq (RTC_IRQ
, NULL
);
1122 #endif /* __sparc__ */
1125 module_init(rtc_init
);
1126 module_exit(rtc_exit
);
1130 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1131 * (usually during an IDE disk interrupt, with IRQ unmasking off)
1132 * Since the interrupt handler doesn't get called, the IRQ status
1133 * byte doesn't get read, and the RTC stops generating interrupts.
1134 * A timer is set, and will call this function if/when that happens.
1135 * To get it out of this stalled state, we just read the status.
1136 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1137 * (You *really* shouldn't be trying to use a non-realtime system
1138 * for something that requires a steady > 1KHz signal anyways.)
1141 static void rtc_dropped_irq(unsigned long data
)
1145 spin_lock_irq (&rtc_lock
);
1147 if (hpet_rtc_dropped_irq()) {
1148 spin_unlock_irq(&rtc_lock
);
1152 /* Just in case someone disabled the timer from behind our back... */
1153 if (rtc_status
& RTC_TIMER_ON
)
1154 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100);
1156 rtc_irq_data
+= ((rtc_freq
/HZ
)<<8);
1157 rtc_irq_data
&= ~0xff;
1158 rtc_irq_data
|= (CMOS_READ(RTC_INTR_FLAGS
) & 0xF0); /* restart */
1162 spin_unlock_irq(&rtc_lock
);
1164 printk(KERN_WARNING
"rtc: lost some interrupts at %ldHz.\n", freq
);
1166 /* Now we have new data */
1167 wake_up_interruptible(&rtc_wait
);
1169 kill_fasync (&rtc_async_queue
, SIGIO
, POLL_IN
);
1173 #ifdef CONFIG_PROC_FS
1175 * Info exported via "/proc/driver/rtc".
1178 static int rtc_proc_show(struct seq_file
*seq
, void *v
)
1180 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1181 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1183 unsigned char batt
, ctrl
;
1186 spin_lock_irq(&rtc_lock
);
1187 batt
= CMOS_READ(RTC_VALID
) & RTC_VRT
;
1188 ctrl
= CMOS_READ(RTC_CONTROL
);
1190 spin_unlock_irq(&rtc_lock
);
1193 rtc_get_rtc_time(&tm
);
1196 * There is no way to tell if the luser has the RTC set for local
1197 * time or for Universal Standard Time (GMT). Probably local though.
1200 "rtc_time\t: %02d:%02d:%02d\n"
1201 "rtc_date\t: %04d-%02d-%02d\n"
1202 "rtc_epoch\t: %04lu\n",
1203 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
,
1204 tm
.tm_year
+ 1900, tm
.tm_mon
+ 1, tm
.tm_mday
, epoch
);
1206 get_rtc_alm_time(&tm
);
1209 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1210 * match any value for that particular field. Values that are
1211 * greater than a valid time, but less than 0xc0 shouldn't appear.
1213 seq_puts(seq
, "alarm\t\t: ");
1214 if (tm
.tm_hour
<= 24)
1215 seq_printf(seq
, "%02d:", tm
.tm_hour
);
1217 seq_puts(seq
, "**:");
1219 if (tm
.tm_min
<= 59)
1220 seq_printf(seq
, "%02d:", tm
.tm_min
);
1222 seq_puts(seq
, "**:");
1224 if (tm
.tm_sec
<= 59)
1225 seq_printf(seq
, "%02d\n", tm
.tm_sec
);
1227 seq_puts(seq
, "**\n");
1230 "DST_enable\t: %s\n"
1233 "square_wave\t: %s\n"
1235 "update_IRQ\t: %s\n"
1236 "periodic_IRQ\t: %s\n"
1237 "periodic_freq\t: %ld\n"
1238 "batt_status\t: %s\n",
1247 batt
? "okay" : "dead");
1254 static int rtc_proc_open(struct inode
*inode
, struct file
*file
)
1256 return single_open(file
, rtc_proc_show
, NULL
);
1260 void rtc_get_rtc_time(struct rtc_time
*rtc_tm
)
1262 unsigned long uip_watchdog
= jiffies
, flags
;
1264 #ifdef CONFIG_MACH_DECSTATION
1265 unsigned int real_year
;
1269 * read RTC once any update in progress is done. The update
1270 * can take just over 2ms. We wait 20ms. There is no need to
1271 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1272 * If you need to know *exactly* when a second has started, enable
1273 * periodic update complete interrupts, (via ioctl) and then
1274 * immediately read /dev/rtc which will block until you get the IRQ.
1275 * Once the read clears, read the RTC time (again via ioctl). Easy.
1278 while (rtc_is_updating() != 0 && jiffies
- uip_watchdog
< 2*HZ
/100)
1282 * Only the values that we read from the RTC are set. We leave
1283 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1284 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1285 * only updated by the RTC when initially set to a non-zero value.
1287 spin_lock_irqsave(&rtc_lock
, flags
);
1288 rtc_tm
->tm_sec
= CMOS_READ(RTC_SECONDS
);
1289 rtc_tm
->tm_min
= CMOS_READ(RTC_MINUTES
);
1290 rtc_tm
->tm_hour
= CMOS_READ(RTC_HOURS
);
1291 rtc_tm
->tm_mday
= CMOS_READ(RTC_DAY_OF_MONTH
);
1292 rtc_tm
->tm_mon
= CMOS_READ(RTC_MONTH
);
1293 rtc_tm
->tm_year
= CMOS_READ(RTC_YEAR
);
1294 /* Only set from 2.6.16 onwards */
1295 rtc_tm
->tm_wday
= CMOS_READ(RTC_DAY_OF_WEEK
);
1297 #ifdef CONFIG_MACH_DECSTATION
1298 real_year
= CMOS_READ(RTC_DEC_YEAR
);
1300 ctrl
= CMOS_READ(RTC_CONTROL
);
1301 spin_unlock_irqrestore(&rtc_lock
, flags
);
1303 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1305 BCD_TO_BIN(rtc_tm
->tm_sec
);
1306 BCD_TO_BIN(rtc_tm
->tm_min
);
1307 BCD_TO_BIN(rtc_tm
->tm_hour
);
1308 BCD_TO_BIN(rtc_tm
->tm_mday
);
1309 BCD_TO_BIN(rtc_tm
->tm_mon
);
1310 BCD_TO_BIN(rtc_tm
->tm_year
);
1311 BCD_TO_BIN(rtc_tm
->tm_wday
);
1314 #ifdef CONFIG_MACH_DECSTATION
1315 rtc_tm
->tm_year
+= real_year
- 72;
1319 * Account for differences between how the RTC uses the values
1320 * and how they are defined in a struct rtc_time;
1322 if ((rtc_tm
->tm_year
+= (epoch
- 1900)) <= 69)
1323 rtc_tm
->tm_year
+= 100;
1328 static void get_rtc_alm_time(struct rtc_time
*alm_tm
)
1333 * Only the values that we read from the RTC are set. That
1334 * means only tm_hour, tm_min, and tm_sec.
1336 spin_lock_irq(&rtc_lock
);
1337 alm_tm
->tm_sec
= CMOS_READ(RTC_SECONDS_ALARM
);
1338 alm_tm
->tm_min
= CMOS_READ(RTC_MINUTES_ALARM
);
1339 alm_tm
->tm_hour
= CMOS_READ(RTC_HOURS_ALARM
);
1340 ctrl
= CMOS_READ(RTC_CONTROL
);
1341 spin_unlock_irq(&rtc_lock
);
1343 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1345 BCD_TO_BIN(alm_tm
->tm_sec
);
1346 BCD_TO_BIN(alm_tm
->tm_min
);
1347 BCD_TO_BIN(alm_tm
->tm_hour
);
1353 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1354 * Rumour has it that if you frob the interrupt enable/disable
1355 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1356 * ensure you actually start getting interrupts. Probably for
1357 * compatibility with older/broken chipset RTC implementations.
1358 * We also clear out any old irq data after an ioctl() that
1359 * meddles with the interrupt enable/disable bits.
1362 static void mask_rtc_irq_bit_locked(unsigned char bit
)
1366 if (hpet_mask_rtc_irq_bit(bit
))
1368 val
= CMOS_READ(RTC_CONTROL
);
1370 CMOS_WRITE(val
, RTC_CONTROL
);
1371 CMOS_READ(RTC_INTR_FLAGS
);
1376 static void set_rtc_irq_bit_locked(unsigned char bit
)
1380 if (hpet_set_rtc_irq_bit(bit
))
1382 val
= CMOS_READ(RTC_CONTROL
);
1384 CMOS_WRITE(val
, RTC_CONTROL
);
1385 CMOS_READ(RTC_INTR_FLAGS
);
1391 MODULE_AUTHOR("Paul Gortmaker");
1392 MODULE_LICENSE("GPL");
1393 MODULE_ALIAS_MISCDEV(RTC_MINOR
);