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
51 * 1.12b David John: Remove calls to the BKL.
54 #define RTC_VERSION "1.12b"
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 time.c vs.
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>
84 #include <asm/current.h>
85 #include <asm/system.h>
93 #include <linux/of_device.h>
96 static unsigned long rtc_port
;
100 #ifdef CONFIG_HPET_EMULATE_RTC
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
116 #define hpet_register_irq_handler(h) ({ 0; })
117 #define hpet_unregister_irq_handler(h) ({ 0; })
119 static 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 long rtc_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
147 static void rtc_get_rtc_time(struct rtc_time
*rtc_tm
);
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 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)
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 */
198 * rtc_task_lock nests inside rtc_lock.
200 static DEFINE_SPINLOCK(rtc_task_lock
);
201 static rtc_task_t
*rtc_callback
;
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 static irqreturn_t
rtc_interrupt(int irq
, void *dev_id
)
233 * Can be an alarm interrupt, update complete interrupt,
234 * or a periodic interrupt. We store the status in the
235 * low byte and the number of interrupts received since
236 * the last read in the remainder of rtc_irq_data.
239 spin_lock(&rtc_lock
);
240 rtc_irq_data
+= 0x100;
241 rtc_irq_data
&= ~0xff;
242 if (is_hpet_enabled()) {
244 * In this case it is HPET RTC interrupt handler
245 * calling us, with the interrupt information
246 * passed as arg1, instead of irq.
248 rtc_irq_data
|= (unsigned long)irq
& 0xF0;
250 rtc_irq_data
|= (CMOS_READ(RTC_INTR_FLAGS
) & 0xF0);
253 if (rtc_status
& RTC_TIMER_ON
)
254 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100);
256 spin_unlock(&rtc_lock
);
258 /* Now do the rest of the actions */
259 spin_lock(&rtc_task_lock
);
261 rtc_callback
->func(rtc_callback
->private_data
);
262 spin_unlock(&rtc_task_lock
);
263 wake_up_interruptible(&rtc_wait
);
265 kill_fasync(&rtc_async_queue
, SIGIO
, POLL_IN
);
272 * sysctl-tuning infrastructure.
274 static ctl_table rtc_table
[] = {
276 .procname
= "max-user-freq",
277 .data
= &rtc_max_user_freq
,
278 .maxlen
= sizeof(int),
280 .proc_handler
= proc_dointvec
,
285 static ctl_table rtc_root
[] = {
294 static ctl_table dev_root
[] = {
303 static struct ctl_table_header
*sysctl_header
;
305 static int __init
init_sysctl(void)
307 sysctl_header
= register_sysctl_table(dev_root
);
311 static void __exit
cleanup_sysctl(void)
313 unregister_sysctl_table(sysctl_header
);
317 * Now all the various file operations that we export.
320 static ssize_t
rtc_read(struct file
*file
, char __user
*buf
,
321 size_t count
, loff_t
*ppos
)
326 DECLARE_WAITQUEUE(wait
, current
);
330 if (rtc_has_irq
== 0)
334 * Historically this function used to assume that sizeof(unsigned long)
335 * is the same in userspace and kernelspace. This lead to problems
336 * for configurations with multiple ABIs such a the MIPS o32 and 64
337 * ABIs supported on the same kernel. So now we support read of both
338 * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
341 if (count
!= sizeof(unsigned int) && count
!= sizeof(unsigned long))
344 add_wait_queue(&rtc_wait
, &wait
);
347 /* First make it right. Then make it fast. Putting this whole
348 * block within the parentheses of a while would be too
349 * confusing. And no, xchg() is not the answer. */
351 __set_current_state(TASK_INTERRUPTIBLE
);
353 spin_lock_irq(&rtc_lock
);
356 spin_unlock_irq(&rtc_lock
);
361 if (file
->f_flags
& O_NONBLOCK
) {
365 if (signal_pending(current
)) {
366 retval
= -ERESTARTSYS
;
372 if (count
== sizeof(unsigned int)) {
373 retval
= put_user(data
,
374 (unsigned int __user
*)buf
) ?: sizeof(int);
376 retval
= put_user(data
,
377 (unsigned long __user
*)buf
) ?: sizeof(long);
382 __set_current_state(TASK_RUNNING
);
383 remove_wait_queue(&rtc_wait
, &wait
);
389 static int rtc_do_ioctl(unsigned int cmd
, unsigned long arg
, int kernel
)
391 struct rtc_time wtime
;
394 if (rtc_has_irq
== 0) {
411 case RTC_AIE_OFF
: /* Mask alarm int. enab. bit */
413 mask_rtc_irq_bit(RTC_AIE
);
416 case RTC_AIE_ON
: /* Allow alarm interrupts. */
418 set_rtc_irq_bit(RTC_AIE
);
421 case RTC_PIE_OFF
: /* Mask periodic int. enab. bit */
423 /* can be called from isr via rtc_control() */
426 spin_lock_irqsave(&rtc_lock
, flags
);
427 mask_rtc_irq_bit_locked(RTC_PIE
);
428 if (rtc_status
& RTC_TIMER_ON
) {
429 rtc_status
&= ~RTC_TIMER_ON
;
430 del_timer(&rtc_irq_timer
);
432 spin_unlock_irqrestore(&rtc_lock
, flags
);
436 case RTC_PIE_ON
: /* Allow periodic ints */
438 /* can be called from isr via rtc_control() */
442 * We don't really want Joe User enabling more
443 * than 64Hz of interrupts on a multi-user machine.
445 if (!kernel
&& (rtc_freq
> rtc_max_user_freq
) &&
446 (!capable(CAP_SYS_RESOURCE
)))
449 spin_lock_irqsave(&rtc_lock
, flags
);
450 if (!(rtc_status
& RTC_TIMER_ON
)) {
451 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+
453 rtc_status
|= RTC_TIMER_ON
;
455 set_rtc_irq_bit_locked(RTC_PIE
);
456 spin_unlock_irqrestore(&rtc_lock
, flags
);
460 case RTC_UIE_OFF
: /* Mask ints from RTC updates. */
462 mask_rtc_irq_bit(RTC_UIE
);
465 case RTC_UIE_ON
: /* Allow ints for RTC updates. */
467 set_rtc_irq_bit(RTC_UIE
);
471 case RTC_ALM_READ
: /* Read the present alarm time */
474 * This returns a struct rtc_time. Reading >= 0xc0
475 * means "don't care" or "match all". Only the tm_hour,
476 * tm_min, and tm_sec values are filled in.
478 memset(&wtime
, 0, sizeof(struct rtc_time
));
479 get_rtc_alm_time(&wtime
);
482 case RTC_ALM_SET
: /* Store a time into the alarm */
485 * This expects a struct rtc_time. Writing 0xff means
486 * "don't care" or "match all". Only the tm_hour,
487 * tm_min and tm_sec are used.
489 unsigned char hrs
, min
, sec
;
490 struct rtc_time alm_tm
;
492 if (copy_from_user(&alm_tm
, (struct rtc_time __user
*)arg
,
493 sizeof(struct rtc_time
)))
496 hrs
= alm_tm
.tm_hour
;
500 spin_lock_irq(&rtc_lock
);
501 if (hpet_set_alarm_time(hrs
, min
, sec
)) {
503 * Fallthru and set alarm time in CMOS too,
504 * so that we will get proper value in RTC_ALM_READ
507 if (!(CMOS_READ(RTC_CONTROL
) & RTC_DM_BINARY
) ||
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))
576 if (yrs
> 255) /* They are unsigned */
579 spin_lock_irq(&rtc_lock
);
580 #ifdef CONFIG_MACH_DECSTATION
585 * We want to keep the year set to 73 until March
586 * for non-leap years, so that Feb, 29th is handled
589 if (!leap_yr
&& mon
< 3) {
594 /* These limits and adjustments are independent of
595 * whether the chip is in binary mode or not.
598 spin_unlock_irq(&rtc_lock
);
604 if (!(CMOS_READ(RTC_CONTROL
) & RTC_DM_BINARY
)
614 save_control
= CMOS_READ(RTC_CONTROL
);
615 CMOS_WRITE((save_control
|RTC_SET
), RTC_CONTROL
);
616 save_freq_select
= CMOS_READ(RTC_FREQ_SELECT
);
617 CMOS_WRITE((save_freq_select
|RTC_DIV_RESET2
), RTC_FREQ_SELECT
);
619 #ifdef CONFIG_MACH_DECSTATION
620 CMOS_WRITE(real_yrs
, RTC_DEC_YEAR
);
622 CMOS_WRITE(yrs
, RTC_YEAR
);
623 CMOS_WRITE(mon
, RTC_MONTH
);
624 CMOS_WRITE(day
, RTC_DAY_OF_MONTH
);
625 CMOS_WRITE(hrs
, RTC_HOURS
);
626 CMOS_WRITE(min
, RTC_MINUTES
);
627 CMOS_WRITE(sec
, RTC_SECONDS
);
629 CMOS_WRITE(save_control
, RTC_CONTROL
);
630 CMOS_WRITE(save_freq_select
, RTC_FREQ_SELECT
);
632 spin_unlock_irq(&rtc_lock
);
636 case RTC_IRQP_READ
: /* Read the periodic IRQ rate. */
638 return put_user(rtc_freq
, (unsigned long __user
*)arg
);
640 case RTC_IRQP_SET
: /* Set periodic IRQ rate. */
644 /* can be called from isr via rtc_control() */
648 * The max we can do is 8192Hz.
650 if ((arg
< 2) || (arg
> 8192))
653 * We don't really want Joe User generating more
654 * than 64Hz of interrupts on a multi-user machine.
656 if (!kernel
&& (arg
> rtc_max_user_freq
) &&
657 !capable(CAP_SYS_RESOURCE
))
660 while (arg
> (1<<tmp
))
664 * Check that the input was really a power of 2.
671 spin_lock_irqsave(&rtc_lock
, flags
);
672 if (hpet_set_periodic_freq(arg
)) {
673 spin_unlock_irqrestore(&rtc_lock
, flags
);
677 val
= CMOS_READ(RTC_FREQ_SELECT
) & 0xf0;
679 CMOS_WRITE(val
, RTC_FREQ_SELECT
);
680 spin_unlock_irqrestore(&rtc_lock
, flags
);
684 case RTC_EPOCH_READ
: /* Read the epoch. */
686 return put_user(epoch
, (unsigned long __user
*)arg
);
688 case RTC_EPOCH_SET
: /* Set the epoch. */
691 * There were no RTC clocks before 1900.
696 if (!capable(CAP_SYS_TIME
))
705 return copy_to_user((void __user
*)arg
,
706 &wtime
, sizeof wtime
) ? -EFAULT
: 0;
709 static long rtc_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
712 ret
= rtc_do_ioctl(cmd
, arg
, 0);
717 * We enforce only one user at a time here with the open/close.
718 * Also clear the previous interrupt data on an open, and clean
719 * up things on a close.
721 static int rtc_open(struct inode
*inode
, struct file
*file
)
723 spin_lock_irq(&rtc_lock
);
725 if (rtc_status
& RTC_IS_OPEN
)
728 rtc_status
|= RTC_IS_OPEN
;
731 spin_unlock_irq(&rtc_lock
);
735 spin_unlock_irq(&rtc_lock
);
739 static int rtc_fasync(int fd
, struct file
*filp
, int on
)
741 return fasync_helper(fd
, filp
, on
, &rtc_async_queue
);
744 static int rtc_release(struct inode
*inode
, struct file
*file
)
749 if (rtc_has_irq
== 0)
753 * Turn off all interrupts once the device is no longer
754 * in use, and clear the data.
757 spin_lock_irq(&rtc_lock
);
758 if (!hpet_mask_rtc_irq_bit(RTC_PIE
| RTC_AIE
| RTC_UIE
)) {
759 tmp
= CMOS_READ(RTC_CONTROL
);
763 CMOS_WRITE(tmp
, RTC_CONTROL
);
764 CMOS_READ(RTC_INTR_FLAGS
);
766 if (rtc_status
& RTC_TIMER_ON
) {
767 rtc_status
&= ~RTC_TIMER_ON
;
768 del_timer(&rtc_irq_timer
);
770 spin_unlock_irq(&rtc_lock
);
775 spin_lock_irq(&rtc_lock
);
777 rtc_status
&= ~RTC_IS_OPEN
;
778 spin_unlock_irq(&rtc_lock
);
784 static unsigned int rtc_poll(struct file
*file
, poll_table
*wait
)
788 if (rtc_has_irq
== 0)
791 poll_wait(file
, &rtc_wait
, wait
);
793 spin_lock_irq(&rtc_lock
);
795 spin_unlock_irq(&rtc_lock
);
798 return POLLIN
| POLLRDNORM
;
803 int rtc_register(rtc_task_t
*task
)
808 if (task
== NULL
|| task
->func
== NULL
)
810 spin_lock_irq(&rtc_lock
);
811 if (rtc_status
& RTC_IS_OPEN
) {
812 spin_unlock_irq(&rtc_lock
);
815 spin_lock(&rtc_task_lock
);
817 spin_unlock(&rtc_task_lock
);
818 spin_unlock_irq(&rtc_lock
);
821 rtc_status
|= RTC_IS_OPEN
;
823 spin_unlock(&rtc_task_lock
);
824 spin_unlock_irq(&rtc_lock
);
828 EXPORT_SYMBOL(rtc_register
);
830 int rtc_unregister(rtc_task_t
*task
)
837 spin_lock_irq(&rtc_lock
);
838 spin_lock(&rtc_task_lock
);
839 if (rtc_callback
!= task
) {
840 spin_unlock(&rtc_task_lock
);
841 spin_unlock_irq(&rtc_lock
);
846 /* disable controls */
847 if (!hpet_mask_rtc_irq_bit(RTC_PIE
| RTC_AIE
| RTC_UIE
)) {
848 tmp
= CMOS_READ(RTC_CONTROL
);
852 CMOS_WRITE(tmp
, RTC_CONTROL
);
853 CMOS_READ(RTC_INTR_FLAGS
);
855 if (rtc_status
& RTC_TIMER_ON
) {
856 rtc_status
&= ~RTC_TIMER_ON
;
857 del_timer(&rtc_irq_timer
);
859 rtc_status
&= ~RTC_IS_OPEN
;
860 spin_unlock(&rtc_task_lock
);
861 spin_unlock_irq(&rtc_lock
);
865 EXPORT_SYMBOL(rtc_unregister
);
867 int rtc_control(rtc_task_t
*task
, unsigned int cmd
, unsigned long arg
)
873 if (cmd
!= RTC_PIE_ON
&& cmd
!= RTC_PIE_OFF
&& cmd
!= RTC_IRQP_SET
)
875 spin_lock_irqsave(&rtc_task_lock
, flags
);
876 if (rtc_callback
!= task
) {
877 spin_unlock_irqrestore(&rtc_task_lock
, flags
);
880 spin_unlock_irqrestore(&rtc_task_lock
, flags
);
881 return rtc_do_ioctl(cmd
, arg
, 1);
884 EXPORT_SYMBOL(rtc_control
);
887 * The various file operations we support.
890 static const struct file_operations rtc_fops
= {
891 .owner
= THIS_MODULE
,
897 .unlocked_ioctl
= rtc_ioctl
,
899 .release
= rtc_release
,
900 .fasync
= rtc_fasync
,
903 static struct miscdevice rtc_dev
= {
909 #ifdef CONFIG_PROC_FS
910 static const struct file_operations rtc_proc_fops
= {
911 .owner
= THIS_MODULE
,
912 .open
= rtc_proc_open
,
915 .release
= single_release
,
919 static resource_size_t rtc_size
;
921 static struct resource
* __init
rtc_request_region(resource_size_t size
)
926 r
= request_region(RTC_PORT(0), size
, "rtc");
928 r
= request_mem_region(RTC_PORT(0), size
, "rtc");
936 static void rtc_release_region(void)
939 release_region(RTC_PORT(0), rtc_size
);
941 release_mem_region(RTC_PORT(0), rtc_size
);
944 static int __init
rtc_init(void)
946 #ifdef CONFIG_PROC_FS
947 struct proc_dir_entry
*ent
;
949 #if defined(__alpha__) || defined(__mips__)
950 unsigned int year
, ctrl
;
953 #ifdef CONFIG_SPARC32
954 struct device_node
*ebus_dp
;
955 struct platform_device
*op
;
959 irq_handler_t rtc_int_handler_ptr
;
963 #ifdef CONFIG_SPARC32
964 for_each_node_by_name(ebus_dp
, "ebus") {
965 struct device_node
*dp
;
966 for (dp
= ebus_dp
; dp
; dp
= dp
->sibling
) {
967 if (!strcmp(dp
->name
, "rtc")) {
968 op
= of_find_device_by_node(dp
);
970 rtc_port
= op
->resource
[0].start
;
971 rtc_irq
= op
->irqs
[0];
978 printk(KERN_ERR
"rtc_init: no PC rtc found\n");
987 if (request_irq(rtc_irq
, rtc_interrupt
, IRQF_SHARED
, "rtc",
988 (void *)&rtc_port
)) {
990 printk(KERN_ERR
"rtc: cannot register IRQ %d\n", rtc_irq
);
995 r
= rtc_request_region(RTC_IO_EXTENT
);
998 * If we've already requested a smaller range (for example, because
999 * PNPBIOS or ACPI told us how the device is configured), the request
1000 * above might fail because it's too big.
1002 * If so, request just the range we actually use.
1005 r
= rtc_request_region(RTC_IO_EXTENT_USED
);
1010 printk(KERN_ERR
"rtc: I/O resource %lx is not free.\n",
1011 (long)(RTC_PORT(0)));
1016 if (is_hpet_enabled()) {
1019 rtc_int_handler_ptr
= hpet_rtc_interrupt
;
1020 err
= hpet_register_irq_handler(rtc_interrupt
);
1022 printk(KERN_WARNING
"hpet_register_irq_handler failed "
1027 rtc_int_handler_ptr
= rtc_interrupt
;
1030 if (request_irq(RTC_IRQ
, rtc_int_handler_ptr
, IRQF_DISABLED
,
1032 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
1034 printk(KERN_ERR
"rtc: IRQ %d is not free.\n", RTC_IRQ
);
1035 rtc_release_region();
1039 hpet_rtc_timer_init();
1043 #endif /* CONFIG_SPARC32 vs. others */
1045 if (misc_register(&rtc_dev
)) {
1047 free_irq(RTC_IRQ
, NULL
);
1048 hpet_unregister_irq_handler(rtc_interrupt
);
1051 rtc_release_region();
1055 #ifdef CONFIG_PROC_FS
1056 ent
= proc_create("driver/rtc", 0, NULL
, &rtc_proc_fops
);
1058 printk(KERN_WARNING
"rtc: Failed to register with procfs.\n");
1061 #if defined(__alpha__) || defined(__mips__)
1064 /* Each operating system on an Alpha uses its own epoch.
1065 Let's try to guess which one we are using now. */
1067 if (rtc_is_updating() != 0)
1070 spin_lock_irq(&rtc_lock
);
1071 year
= CMOS_READ(RTC_YEAR
);
1072 ctrl
= CMOS_READ(RTC_CONTROL
);
1073 spin_unlock_irq(&rtc_lock
);
1075 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1076 year
= bcd2bin(year
); /* This should never happen... */
1080 guess
= "SRM (post-2000)";
1081 } else if (year
>= 20 && year
< 48) {
1083 guess
= "ARC console";
1084 } else if (year
>= 48 && year
< 72) {
1086 guess
= "Digital UNIX";
1087 #if defined(__mips__)
1088 } else if (year
>= 72 && year
< 74) {
1090 guess
= "Digital DECstation";
1092 } else if (year
>= 70) {
1094 guess
= "Standard PC (1900)";
1098 printk(KERN_INFO
"rtc: %s epoch (%lu) detected\n",
1102 if (rtc_has_irq
== 0)
1105 spin_lock_irq(&rtc_lock
);
1107 if (!hpet_set_periodic_freq(rtc_freq
)) {
1109 * Initialize periodic frequency to CMOS reset default,
1112 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT
) & 0xF0) | 0x06),
1115 spin_unlock_irq(&rtc_lock
);
1119 (void) init_sysctl();
1121 printk(KERN_INFO
"Real Time Clock Driver v" RTC_VERSION
"\n");
1126 static void __exit
rtc_exit(void)
1129 remove_proc_entry("driver/rtc", NULL
);
1130 misc_deregister(&rtc_dev
);
1132 #ifdef CONFIG_SPARC32
1134 free_irq(rtc_irq
, &rtc_port
);
1136 rtc_release_region();
1139 free_irq(RTC_IRQ
, NULL
);
1140 hpet_unregister_irq_handler(hpet_rtc_interrupt
);
1143 #endif /* CONFIG_SPARC32 */
1146 module_init(rtc_init
);
1147 module_exit(rtc_exit
);
1151 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1152 * (usually during an IDE disk interrupt, with IRQ unmasking off)
1153 * Since the interrupt handler doesn't get called, the IRQ status
1154 * byte doesn't get read, and the RTC stops generating interrupts.
1155 * A timer is set, and will call this function if/when that happens.
1156 * To get it out of this stalled state, we just read the status.
1157 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1158 * (You *really* shouldn't be trying to use a non-realtime system
1159 * for something that requires a steady > 1KHz signal anyways.)
1162 static void rtc_dropped_irq(unsigned long data
)
1166 spin_lock_irq(&rtc_lock
);
1168 if (hpet_rtc_dropped_irq()) {
1169 spin_unlock_irq(&rtc_lock
);
1173 /* Just in case someone disabled the timer from behind our back... */
1174 if (rtc_status
& RTC_TIMER_ON
)
1175 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100);
1177 rtc_irq_data
+= ((rtc_freq
/HZ
)<<8);
1178 rtc_irq_data
&= ~0xff;
1179 rtc_irq_data
|= (CMOS_READ(RTC_INTR_FLAGS
) & 0xF0); /* restart */
1183 spin_unlock_irq(&rtc_lock
);
1185 if (printk_ratelimit()) {
1186 printk(KERN_WARNING
"rtc: lost some interrupts at %ldHz.\n",
1190 /* Now we have new data */
1191 wake_up_interruptible(&rtc_wait
);
1193 kill_fasync(&rtc_async_queue
, SIGIO
, POLL_IN
);
1197 #ifdef CONFIG_PROC_FS
1199 * Info exported via "/proc/driver/rtc".
1202 static int rtc_proc_show(struct seq_file
*seq
, void *v
)
1204 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1205 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1207 unsigned char batt
, ctrl
;
1210 spin_lock_irq(&rtc_lock
);
1211 batt
= CMOS_READ(RTC_VALID
) & RTC_VRT
;
1212 ctrl
= CMOS_READ(RTC_CONTROL
);
1214 spin_unlock_irq(&rtc_lock
);
1217 rtc_get_rtc_time(&tm
);
1220 * There is no way to tell if the luser has the RTC set for local
1221 * time or for Universal Standard Time (GMT). Probably local though.
1224 "rtc_time\t: %02d:%02d:%02d\n"
1225 "rtc_date\t: %04d-%02d-%02d\n"
1226 "rtc_epoch\t: %04lu\n",
1227 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
,
1228 tm
.tm_year
+ 1900, tm
.tm_mon
+ 1, tm
.tm_mday
, epoch
);
1230 get_rtc_alm_time(&tm
);
1233 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1234 * match any value for that particular field. Values that are
1235 * greater than a valid time, but less than 0xc0 shouldn't appear.
1237 seq_puts(seq
, "alarm\t\t: ");
1238 if (tm
.tm_hour
<= 24)
1239 seq_printf(seq
, "%02d:", tm
.tm_hour
);
1241 seq_puts(seq
, "**:");
1243 if (tm
.tm_min
<= 59)
1244 seq_printf(seq
, "%02d:", tm
.tm_min
);
1246 seq_puts(seq
, "**:");
1248 if (tm
.tm_sec
<= 59)
1249 seq_printf(seq
, "%02d\n", tm
.tm_sec
);
1251 seq_puts(seq
, "**\n");
1254 "DST_enable\t: %s\n"
1257 "square_wave\t: %s\n"
1259 "update_IRQ\t: %s\n"
1260 "periodic_IRQ\t: %s\n"
1261 "periodic_freq\t: %ld\n"
1262 "batt_status\t: %s\n",
1271 batt
? "okay" : "dead");
1278 static int rtc_proc_open(struct inode
*inode
, struct file
*file
)
1280 return single_open(file
, rtc_proc_show
, NULL
);
1284 static void rtc_get_rtc_time(struct rtc_time
*rtc_tm
)
1286 unsigned long uip_watchdog
= jiffies
, flags
;
1288 #ifdef CONFIG_MACH_DECSTATION
1289 unsigned int real_year
;
1293 * read RTC once any update in progress is done. The update
1294 * can take just over 2ms. We wait 20ms. There is no need to
1295 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1296 * If you need to know *exactly* when a second has started, enable
1297 * periodic update complete interrupts, (via ioctl) and then
1298 * immediately read /dev/rtc which will block until you get the IRQ.
1299 * Once the read clears, read the RTC time (again via ioctl). Easy.
1302 while (rtc_is_updating() != 0 &&
1303 time_before(jiffies
, uip_watchdog
+ 2*HZ
/100))
1307 * Only the values that we read from the RTC are set. We leave
1308 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1309 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1310 * only updated by the RTC when initially set to a non-zero value.
1312 spin_lock_irqsave(&rtc_lock
, flags
);
1313 rtc_tm
->tm_sec
= CMOS_READ(RTC_SECONDS
);
1314 rtc_tm
->tm_min
= CMOS_READ(RTC_MINUTES
);
1315 rtc_tm
->tm_hour
= CMOS_READ(RTC_HOURS
);
1316 rtc_tm
->tm_mday
= CMOS_READ(RTC_DAY_OF_MONTH
);
1317 rtc_tm
->tm_mon
= CMOS_READ(RTC_MONTH
);
1318 rtc_tm
->tm_year
= CMOS_READ(RTC_YEAR
);
1319 /* Only set from 2.6.16 onwards */
1320 rtc_tm
->tm_wday
= CMOS_READ(RTC_DAY_OF_WEEK
);
1322 #ifdef CONFIG_MACH_DECSTATION
1323 real_year
= CMOS_READ(RTC_DEC_YEAR
);
1325 ctrl
= CMOS_READ(RTC_CONTROL
);
1326 spin_unlock_irqrestore(&rtc_lock
, flags
);
1328 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
) {
1329 rtc_tm
->tm_sec
= bcd2bin(rtc_tm
->tm_sec
);
1330 rtc_tm
->tm_min
= bcd2bin(rtc_tm
->tm_min
);
1331 rtc_tm
->tm_hour
= bcd2bin(rtc_tm
->tm_hour
);
1332 rtc_tm
->tm_mday
= bcd2bin(rtc_tm
->tm_mday
);
1333 rtc_tm
->tm_mon
= bcd2bin(rtc_tm
->tm_mon
);
1334 rtc_tm
->tm_year
= bcd2bin(rtc_tm
->tm_year
);
1335 rtc_tm
->tm_wday
= bcd2bin(rtc_tm
->tm_wday
);
1338 #ifdef CONFIG_MACH_DECSTATION
1339 rtc_tm
->tm_year
+= real_year
- 72;
1343 * Account for differences between how the RTC uses the values
1344 * and how they are defined in a struct rtc_time;
1346 rtc_tm
->tm_year
+= epoch
- 1900;
1347 if (rtc_tm
->tm_year
<= 69)
1348 rtc_tm
->tm_year
+= 100;
1353 static void get_rtc_alm_time(struct rtc_time
*alm_tm
)
1358 * Only the values that we read from the RTC are set. That
1359 * means only tm_hour, tm_min, and tm_sec.
1361 spin_lock_irq(&rtc_lock
);
1362 alm_tm
->tm_sec
= CMOS_READ(RTC_SECONDS_ALARM
);
1363 alm_tm
->tm_min
= CMOS_READ(RTC_MINUTES_ALARM
);
1364 alm_tm
->tm_hour
= CMOS_READ(RTC_HOURS_ALARM
);
1365 ctrl
= CMOS_READ(RTC_CONTROL
);
1366 spin_unlock_irq(&rtc_lock
);
1368 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
) {
1369 alm_tm
->tm_sec
= bcd2bin(alm_tm
->tm_sec
);
1370 alm_tm
->tm_min
= bcd2bin(alm_tm
->tm_min
);
1371 alm_tm
->tm_hour
= bcd2bin(alm_tm
->tm_hour
);
1377 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1378 * Rumour has it that if you frob the interrupt enable/disable
1379 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1380 * ensure you actually start getting interrupts. Probably for
1381 * compatibility with older/broken chipset RTC implementations.
1382 * We also clear out any old irq data after an ioctl() that
1383 * meddles with the interrupt enable/disable bits.
1386 static void mask_rtc_irq_bit_locked(unsigned char bit
)
1390 if (hpet_mask_rtc_irq_bit(bit
))
1392 val
= CMOS_READ(RTC_CONTROL
);
1394 CMOS_WRITE(val
, RTC_CONTROL
);
1395 CMOS_READ(RTC_INTR_FLAGS
);
1400 static void set_rtc_irq_bit_locked(unsigned char bit
)
1404 if (hpet_set_rtc_irq_bit(bit
))
1406 val
= CMOS_READ(RTC_CONTROL
);
1408 CMOS_WRITE(val
, RTC_CONTROL
);
1409 CMOS_READ(RTC_INTR_FLAGS
);
1415 MODULE_AUTHOR("Paul Gortmaker");
1416 MODULE_LICENSE("GPL");
1417 MODULE_ALIAS_MISCDEV(RTC_MINOR
);