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 * 1.12ac Alan Cox: Allow read access to the day of week register
52 #define RTC_VERSION "1.12ac"
54 #define RTC_IO_EXTENT 0x8
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/sysctl.h>
78 #include <linux/wait.h>
79 #include <linux/bcd.h>
80 #include <linux/delay.h>
82 #include <asm/current.h>
83 #include <asm/uaccess.h>
84 #include <asm/system.h>
91 #include <linux/pci.h>
97 static unsigned long rtc_port
;
98 static int rtc_irq
= PCI_IRQ_NONE
;
101 #ifdef CONFIG_HPET_RTC_IRQ
106 static int rtc_has_irq
= 1;
109 #ifndef CONFIG_HPET_EMULATE_RTC
110 #define is_hpet_enabled() 0
111 #define hpet_set_alarm_time(hrs, min, sec) 0
112 #define hpet_set_periodic_freq(arg) 0
113 #define hpet_mask_rtc_irq_bit(arg) 0
114 #define hpet_set_rtc_irq_bit(arg) 0
115 #define hpet_rtc_timer_init() do { } while (0)
116 #define hpet_rtc_dropped_irq() 0
117 static inline irqreturn_t
hpet_rtc_interrupt(int irq
, void *dev_id
, struct pt_regs
*regs
) {return 0;}
119 extern irqreturn_t
hpet_rtc_interrupt(int irq
, void *dev_id
, struct pt_regs
*regs
);
123 * We sponge a minor off of the misc major. No need slurping
124 * up another valuable major dev number for this. If you add
125 * an ioctl, make sure you don't conflict with SPARC's RTC
129 static struct fasync_struct
*rtc_async_queue
;
131 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait
);
134 static struct timer_list rtc_irq_timer
;
137 static ssize_t
rtc_read(struct file
*file
, char __user
*buf
,
138 size_t count
, loff_t
*ppos
);
140 static int rtc_ioctl(struct inode
*inode
, struct file
*file
,
141 unsigned int cmd
, unsigned long arg
);
144 static unsigned int rtc_poll(struct file
*file
, poll_table
*wait
);
147 static void get_rtc_alm_time (struct rtc_time
*alm_tm
);
149 static void rtc_dropped_irq(unsigned long data
);
151 static void set_rtc_irq_bit_locked(unsigned char bit
);
152 static void mask_rtc_irq_bit_locked(unsigned char bit
);
154 static inline void set_rtc_irq_bit(unsigned char bit
)
156 spin_lock_irq(&rtc_lock
);
157 set_rtc_irq_bit_locked(bit
);
158 spin_unlock_irq(&rtc_lock
);
161 static void mask_rtc_irq_bit(unsigned char bit
)
163 spin_lock_irq(&rtc_lock
);
164 mask_rtc_irq_bit_locked(bit
);
165 spin_unlock_irq(&rtc_lock
);
169 static int rtc_proc_open(struct inode
*inode
, struct file
*file
);
172 * Bits in rtc_status. (6 bits of room for future expansion)
175 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
176 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
179 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
180 * protected by the big kernel lock. However, ioctl can still disable the timer
181 * in rtc_status and then with del_timer after the interrupt has read
182 * rtc_status but before mod_timer is called, which would then reenable the
183 * timer (but you would need to have an awful timing before you'd trip on it)
185 static unsigned long rtc_status
= 0; /* bitmapped status byte. */
186 static unsigned long rtc_freq
= 0; /* Current periodic IRQ rate */
187 static unsigned long rtc_irq_data
= 0; /* our output to the world */
188 static unsigned long rtc_max_user_freq
= 64; /* > this, need CAP_SYS_RESOURCE */
192 * rtc_task_lock nests inside rtc_lock.
194 static DEFINE_SPINLOCK(rtc_task_lock
);
195 static rtc_task_t
*rtc_callback
= NULL
;
199 * If this driver ever becomes modularised, it will be really nice
200 * to make the epoch retain its value across module reload...
203 static unsigned long epoch
= 1900; /* year corresponding to 0x00 */
205 static const unsigned char days_in_mo
[] =
206 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
209 * Returns true if a clock update is in progress
211 static inline unsigned char rtc_is_updating(void)
215 spin_lock_irq(&rtc_lock
);
216 uip
= (CMOS_READ(RTC_FREQ_SELECT
) & RTC_UIP
);
217 spin_unlock_irq(&rtc_lock
);
223 * A very tiny interrupt handler. It runs with SA_INTERRUPT set,
224 * but there is possibility of conflicting with the set_rtc_mmss()
225 * call (the rtc irq and the timer irq can easily run at the same
226 * time in two different CPUs). So we need to serialize
227 * accesses to the chip with the rtc_lock spinlock that each
228 * architecture should implement in the timer code.
229 * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
232 irqreturn_t
rtc_interrupt(int irq
, void *dev_id
, struct pt_regs
*regs
)
235 * Can be an alarm interrupt, update complete interrupt,
236 * or a periodic interrupt. We store the status in the
237 * low byte and the number of interrupts received since
238 * the last read in the remainder of rtc_irq_data.
241 spin_lock (&rtc_lock
);
242 rtc_irq_data
+= 0x100;
243 rtc_irq_data
&= ~0xff;
244 if (is_hpet_enabled()) {
246 * In this case it is HPET RTC interrupt handler
247 * calling us, with the interrupt information
248 * passed as arg1, instead of irq.
250 rtc_irq_data
|= (unsigned long)irq
& 0xF0;
252 rtc_irq_data
|= (CMOS_READ(RTC_INTR_FLAGS
) & 0xF0);
255 if (rtc_status
& RTC_TIMER_ON
)
256 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100);
258 spin_unlock (&rtc_lock
);
260 /* Now do the rest of the actions */
261 spin_lock(&rtc_task_lock
);
263 rtc_callback
->func(rtc_callback
->private_data
);
264 spin_unlock(&rtc_task_lock
);
265 wake_up_interruptible(&rtc_wait
);
267 kill_fasync (&rtc_async_queue
, SIGIO
, POLL_IN
);
274 * sysctl-tuning infrastructure.
276 static ctl_table rtc_table
[] = {
279 .procname
= "max-user-freq",
280 .data
= &rtc_max_user_freq
,
281 .maxlen
= sizeof(int),
283 .proc_handler
= &proc_dointvec
,
288 static ctl_table rtc_root
[] = {
299 static ctl_table dev_root
[] = {
310 static struct ctl_table_header
*sysctl_header
;
312 static int __init
init_sysctl(void)
314 sysctl_header
= register_sysctl_table(dev_root
, 0);
318 static void __exit
cleanup_sysctl(void)
320 unregister_sysctl_table(sysctl_header
);
324 * Now all the various file operations that we export.
327 static ssize_t
rtc_read(struct file
*file
, char __user
*buf
,
328 size_t count
, loff_t
*ppos
)
333 DECLARE_WAITQUEUE(wait
, current
);
337 if (rtc_has_irq
== 0)
340 if (count
< sizeof(unsigned))
343 add_wait_queue(&rtc_wait
, &wait
);
346 /* First make it right. Then make it fast. Putting this whole
347 * block within the parentheses of a while would be too
348 * confusing. And no, xchg() is not the answer. */
350 __set_current_state(TASK_INTERRUPTIBLE
);
352 spin_lock_irq (&rtc_lock
);
355 spin_unlock_irq (&rtc_lock
);
360 if (file
->f_flags
& O_NONBLOCK
) {
364 if (signal_pending(current
)) {
365 retval
= -ERESTARTSYS
;
371 if (count
< sizeof(unsigned long))
372 retval
= put_user(data
, (unsigned int __user
*)buf
) ?: sizeof(int);
374 retval
= put_user(data
, (unsigned long __user
*)buf
) ?: sizeof(long);
376 current
->state
= TASK_RUNNING
;
377 remove_wait_queue(&rtc_wait
, &wait
);
383 static int rtc_do_ioctl(unsigned int cmd
, unsigned long arg
, int kernel
)
385 struct rtc_time wtime
;
388 if (rtc_has_irq
== 0) {
405 case RTC_AIE_OFF
: /* Mask alarm int. enab. bit */
407 mask_rtc_irq_bit(RTC_AIE
);
410 case RTC_AIE_ON
: /* Allow alarm interrupts. */
412 set_rtc_irq_bit(RTC_AIE
);
415 case RTC_PIE_OFF
: /* Mask periodic int. enab. bit */
417 unsigned long flags
; /* can be called from isr via rtc_control() */
418 spin_lock_irqsave (&rtc_lock
, flags
);
419 mask_rtc_irq_bit_locked(RTC_PIE
);
420 if (rtc_status
& RTC_TIMER_ON
) {
421 rtc_status
&= ~RTC_TIMER_ON
;
422 del_timer(&rtc_irq_timer
);
424 spin_unlock_irqrestore (&rtc_lock
, flags
);
427 case RTC_PIE_ON
: /* Allow periodic ints */
429 unsigned long flags
; /* can be called from isr via rtc_control() */
431 * We don't really want Joe User enabling more
432 * than 64Hz of interrupts on a multi-user machine.
434 if (!kernel
&& (rtc_freq
> rtc_max_user_freq
) &&
435 (!capable(CAP_SYS_RESOURCE
)))
438 spin_lock_irqsave (&rtc_lock
, flags
);
439 if (!(rtc_status
& RTC_TIMER_ON
)) {
440 rtc_irq_timer
.expires
= jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100;
441 add_timer(&rtc_irq_timer
);
442 rtc_status
|= RTC_TIMER_ON
;
444 set_rtc_irq_bit_locked(RTC_PIE
);
445 spin_unlock_irqrestore (&rtc_lock
, flags
);
448 case RTC_UIE_OFF
: /* Mask ints from RTC updates. */
450 mask_rtc_irq_bit(RTC_UIE
);
453 case RTC_UIE_ON
: /* Allow ints for RTC updates. */
455 set_rtc_irq_bit(RTC_UIE
);
459 case RTC_ALM_READ
: /* Read the present alarm time */
462 * This returns a struct rtc_time. Reading >= 0xc0
463 * means "don't care" or "match all". Only the tm_hour,
464 * tm_min, and tm_sec values are filled in.
466 memset(&wtime
, 0, sizeof(struct rtc_time
));
467 get_rtc_alm_time(&wtime
);
470 case RTC_ALM_SET
: /* Store a time into the alarm */
473 * This expects a struct rtc_time. Writing 0xff means
474 * "don't care" or "match all". Only the tm_hour,
475 * tm_min and tm_sec are used.
477 unsigned char hrs
, min
, sec
;
478 struct rtc_time alm_tm
;
480 if (copy_from_user(&alm_tm
, (struct rtc_time __user
*)arg
,
481 sizeof(struct rtc_time
)))
484 hrs
= alm_tm
.tm_hour
;
488 spin_lock_irq(&rtc_lock
);
489 if (hpet_set_alarm_time(hrs
, min
, sec
)) {
491 * Fallthru and set alarm time in CMOS too,
492 * so that we will get proper value in RTC_ALM_READ
495 if (!(CMOS_READ(RTC_CONTROL
) & RTC_DM_BINARY
) ||
498 if (sec
< 60) BIN_TO_BCD(sec
);
501 if (min
< 60) BIN_TO_BCD(min
);
504 if (hrs
< 24) BIN_TO_BCD(hrs
);
507 CMOS_WRITE(hrs
, RTC_HOURS_ALARM
);
508 CMOS_WRITE(min
, RTC_MINUTES_ALARM
);
509 CMOS_WRITE(sec
, RTC_SECONDS_ALARM
);
510 spin_unlock_irq(&rtc_lock
);
514 case RTC_RD_TIME
: /* Read the time/date from RTC */
516 memset(&wtime
, 0, sizeof(struct rtc_time
));
517 rtc_get_rtc_time(&wtime
);
520 case RTC_SET_TIME
: /* Set the RTC */
522 struct rtc_time rtc_tm
;
523 unsigned char mon
, day
, hrs
, min
, sec
, leap_yr
;
524 unsigned char save_control
, save_freq_select
;
526 #ifdef CONFIG_MACH_DECSTATION
527 unsigned int real_yrs
;
530 if (!capable(CAP_SYS_TIME
))
533 if (copy_from_user(&rtc_tm
, (struct rtc_time __user
*)arg
,
534 sizeof(struct rtc_time
)))
537 yrs
= rtc_tm
.tm_year
+ 1900;
538 mon
= rtc_tm
.tm_mon
+ 1; /* tm_mon starts at zero */
539 day
= rtc_tm
.tm_mday
;
540 hrs
= rtc_tm
.tm_hour
;
547 leap_yr
= ((!(yrs
% 4) && (yrs
% 100)) || !(yrs
% 400));
549 if ((mon
> 12) || (day
== 0))
552 if (day
> (days_in_mo
[mon
] + ((mon
== 2) && leap_yr
)))
555 if ((hrs
>= 24) || (min
>= 60) || (sec
>= 60))
558 if ((yrs
-= epoch
) > 255) /* They are unsigned */
561 spin_lock_irq(&rtc_lock
);
562 #ifdef CONFIG_MACH_DECSTATION
567 * We want to keep the year set to 73 until March
568 * for non-leap years, so that Feb, 29th is handled
571 if (!leap_yr
&& mon
< 3) {
576 /* These limits and adjustments are independent of
577 * whether the chip is in binary mode or not.
580 spin_unlock_irq(&rtc_lock
);
586 if (!(CMOS_READ(RTC_CONTROL
) & RTC_DM_BINARY
)
596 save_control
= CMOS_READ(RTC_CONTROL
);
597 CMOS_WRITE((save_control
|RTC_SET
), RTC_CONTROL
);
598 save_freq_select
= CMOS_READ(RTC_FREQ_SELECT
);
599 CMOS_WRITE((save_freq_select
|RTC_DIV_RESET2
), RTC_FREQ_SELECT
);
601 #ifdef CONFIG_MACH_DECSTATION
602 CMOS_WRITE(real_yrs
, RTC_DEC_YEAR
);
604 CMOS_WRITE(yrs
, RTC_YEAR
);
605 CMOS_WRITE(mon
, RTC_MONTH
);
606 CMOS_WRITE(day
, RTC_DAY_OF_MONTH
);
607 CMOS_WRITE(hrs
, RTC_HOURS
);
608 CMOS_WRITE(min
, RTC_MINUTES
);
609 CMOS_WRITE(sec
, RTC_SECONDS
);
611 CMOS_WRITE(save_control
, RTC_CONTROL
);
612 CMOS_WRITE(save_freq_select
, RTC_FREQ_SELECT
);
614 spin_unlock_irq(&rtc_lock
);
618 case RTC_IRQP_READ
: /* Read the periodic IRQ rate. */
620 return put_user(rtc_freq
, (unsigned long __user
*)arg
);
622 case RTC_IRQP_SET
: /* Set periodic IRQ rate. */
626 unsigned long flags
; /* can be called from isr via rtc_control() */
629 * The max we can do is 8192Hz.
631 if ((arg
< 2) || (arg
> 8192))
634 * We don't really want Joe User generating more
635 * than 64Hz of interrupts on a multi-user machine.
637 if (!kernel
&& (arg
> rtc_max_user_freq
) && (!capable(CAP_SYS_RESOURCE
)))
640 while (arg
> (1<<tmp
))
644 * Check that the input was really a power of 2.
649 spin_lock_irqsave(&rtc_lock
, flags
);
650 if (hpet_set_periodic_freq(arg
)) {
651 spin_unlock_irqrestore(&rtc_lock
, flags
);
656 val
= CMOS_READ(RTC_FREQ_SELECT
) & 0xf0;
658 CMOS_WRITE(val
, RTC_FREQ_SELECT
);
659 spin_unlock_irqrestore(&rtc_lock
, flags
);
663 case RTC_EPOCH_READ
: /* Read the epoch. */
665 return put_user (epoch
, (unsigned long __user
*)arg
);
667 case RTC_EPOCH_SET
: /* Set the epoch. */
670 * There were no RTC clocks before 1900.
675 if (!capable(CAP_SYS_TIME
))
684 return copy_to_user((void __user
*)arg
, &wtime
, sizeof wtime
) ? -EFAULT
: 0;
687 static int rtc_ioctl(struct inode
*inode
, struct file
*file
, unsigned int cmd
,
690 return rtc_do_ioctl(cmd
, arg
, 0);
694 * We enforce only one user at a time here with the open/close.
695 * Also clear the previous interrupt data on an open, and clean
696 * up things on a close.
699 /* We use rtc_lock to protect against concurrent opens. So the BKL is not
700 * needed here. Or anywhere else in this driver. */
701 static int rtc_open(struct inode
*inode
, struct file
*file
)
703 spin_lock_irq (&rtc_lock
);
705 if(rtc_status
& RTC_IS_OPEN
)
708 rtc_status
|= RTC_IS_OPEN
;
711 spin_unlock_irq (&rtc_lock
);
715 spin_unlock_irq (&rtc_lock
);
719 static int rtc_fasync (int fd
, struct file
*filp
, int on
)
722 return fasync_helper (fd
, filp
, on
, &rtc_async_queue
);
725 static int rtc_release(struct inode
*inode
, struct file
*file
)
730 if (rtc_has_irq
== 0)
734 * Turn off all interrupts once the device is no longer
735 * in use, and clear the data.
738 spin_lock_irq(&rtc_lock
);
739 if (!hpet_mask_rtc_irq_bit(RTC_PIE
| RTC_AIE
| RTC_UIE
)) {
740 tmp
= CMOS_READ(RTC_CONTROL
);
744 CMOS_WRITE(tmp
, RTC_CONTROL
);
745 CMOS_READ(RTC_INTR_FLAGS
);
747 if (rtc_status
& RTC_TIMER_ON
) {
748 rtc_status
&= ~RTC_TIMER_ON
;
749 del_timer(&rtc_irq_timer
);
751 spin_unlock_irq(&rtc_lock
);
753 if (file
->f_flags
& FASYNC
) {
754 rtc_fasync (-1, file
, 0);
759 spin_lock_irq (&rtc_lock
);
761 rtc_status
&= ~RTC_IS_OPEN
;
762 spin_unlock_irq (&rtc_lock
);
767 /* Called without the kernel lock - fine */
768 static unsigned int rtc_poll(struct file
*file
, poll_table
*wait
)
772 if (rtc_has_irq
== 0)
775 poll_wait(file
, &rtc_wait
, wait
);
777 spin_lock_irq (&rtc_lock
);
779 spin_unlock_irq (&rtc_lock
);
782 return POLLIN
| POLLRDNORM
;
791 EXPORT_SYMBOL(rtc_register
);
792 EXPORT_SYMBOL(rtc_unregister
);
793 EXPORT_SYMBOL(rtc_control
);
795 int rtc_register(rtc_task_t
*task
)
800 if (task
== NULL
|| task
->func
== NULL
)
802 spin_lock_irq(&rtc_lock
);
803 if (rtc_status
& RTC_IS_OPEN
) {
804 spin_unlock_irq(&rtc_lock
);
807 spin_lock(&rtc_task_lock
);
809 spin_unlock(&rtc_task_lock
);
810 spin_unlock_irq(&rtc_lock
);
813 rtc_status
|= RTC_IS_OPEN
;
815 spin_unlock(&rtc_task_lock
);
816 spin_unlock_irq(&rtc_lock
);
821 int rtc_unregister(rtc_task_t
*task
)
828 spin_lock_irq(&rtc_lock
);
829 spin_lock(&rtc_task_lock
);
830 if (rtc_callback
!= task
) {
831 spin_unlock(&rtc_task_lock
);
832 spin_unlock_irq(&rtc_lock
);
837 /* disable controls */
838 if (!hpet_mask_rtc_irq_bit(RTC_PIE
| RTC_AIE
| RTC_UIE
)) {
839 tmp
= CMOS_READ(RTC_CONTROL
);
843 CMOS_WRITE(tmp
, RTC_CONTROL
);
844 CMOS_READ(RTC_INTR_FLAGS
);
846 if (rtc_status
& RTC_TIMER_ON
) {
847 rtc_status
&= ~RTC_TIMER_ON
;
848 del_timer(&rtc_irq_timer
);
850 rtc_status
&= ~RTC_IS_OPEN
;
851 spin_unlock(&rtc_task_lock
);
852 spin_unlock_irq(&rtc_lock
);
857 int rtc_control(rtc_task_t
*task
, unsigned int cmd
, unsigned long arg
)
863 if (cmd
!= RTC_PIE_ON
&& cmd
!= RTC_PIE_OFF
&& cmd
!= RTC_IRQP_SET
)
865 spin_lock_irqsave(&rtc_task_lock
, flags
);
866 if (rtc_callback
!= task
) {
867 spin_unlock_irqrestore(&rtc_task_lock
, flags
);
870 spin_unlock_irqrestore(&rtc_task_lock
, flags
);
871 return rtc_do_ioctl(cmd
, arg
, 1);
877 * The various file operations we support.
880 static struct file_operations rtc_fops
= {
881 .owner
= THIS_MODULE
,
889 .release
= rtc_release
,
890 .fasync
= rtc_fasync
,
893 static struct miscdevice rtc_dev
= {
899 static struct file_operations rtc_proc_fops
= {
900 .owner
= THIS_MODULE
,
901 .open
= rtc_proc_open
,
904 .release
= single_release
,
907 #if defined(RTC_IRQ) && !defined(__sparc__)
908 static irqreturn_t (*rtc_int_handler_ptr
)(int irq
, void *dev_id
, struct pt_regs
*regs
);
911 static int __init
rtc_init(void)
913 struct proc_dir_entry
*ent
;
914 #if defined(__alpha__) || defined(__mips__)
915 unsigned int year
, ctrl
;
919 struct linux_ebus
*ebus
;
920 struct linux_ebus_device
*edev
;
922 struct sparc_isa_bridge
*isa_br
;
923 struct sparc_isa_device
*isa_dev
;
928 for_each_ebus(ebus
) {
929 for_each_ebusdev(edev
, ebus
) {
930 if(strcmp(edev
->prom_node
->name
, "rtc") == 0) {
931 rtc_port
= edev
->resource
[0].start
;
932 rtc_irq
= edev
->irqs
[0];
938 for_each_isa(isa_br
) {
939 for_each_isadev(isa_dev
, isa_br
) {
940 if (strcmp(isa_dev
->prom_node
->name
, "rtc") == 0) {
941 rtc_port
= isa_dev
->resource
.start
;
942 rtc_irq
= isa_dev
->irq
;
948 printk(KERN_ERR
"rtc_init: no PC rtc found\n");
952 if (rtc_irq
== PCI_IRQ_NONE
) {
958 * XXX Interrupt pin #7 in Espresso is shared between RTC and
959 * PCI Slot 2 INTA# (and some INTx# in Slot 1).
961 if (request_irq(rtc_irq
, rtc_interrupt
, SA_SHIRQ
, "rtc", (void *)&rtc_port
)) {
962 printk(KERN_ERR
"rtc: cannot register IRQ %d\n", rtc_irq
);
967 if (!request_region(RTC_PORT(0), RTC_IO_EXTENT
, "rtc")) {
968 printk(KERN_ERR
"rtc: I/O port %d is not free.\n", RTC_PORT (0));
973 if (is_hpet_enabled()) {
974 rtc_int_handler_ptr
= hpet_rtc_interrupt
;
976 rtc_int_handler_ptr
= rtc_interrupt
;
979 if(request_irq(RTC_IRQ
, rtc_int_handler_ptr
, SA_INTERRUPT
, "rtc", NULL
)) {
980 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
981 printk(KERN_ERR
"rtc: IRQ %d is not free.\n", RTC_IRQ
);
982 release_region(RTC_PORT(0), RTC_IO_EXTENT
);
985 hpet_rtc_timer_init();
989 #endif /* __sparc__ vs. others */
991 if (misc_register(&rtc_dev
)) {
993 free_irq(RTC_IRQ
, NULL
);
995 release_region(RTC_PORT(0), RTC_IO_EXTENT
);
999 ent
= create_proc_entry("driver/rtc", 0, NULL
);
1002 free_irq(RTC_IRQ
, NULL
);
1004 release_region(RTC_PORT(0), RTC_IO_EXTENT
);
1005 misc_deregister(&rtc_dev
);
1008 ent
->proc_fops
= &rtc_proc_fops
;
1010 #if defined(__alpha__) || defined(__mips__)
1013 /* Each operating system on an Alpha uses its own epoch.
1014 Let's try to guess which one we are using now. */
1016 if (rtc_is_updating() != 0)
1019 spin_lock_irq(&rtc_lock
);
1020 year
= CMOS_READ(RTC_YEAR
);
1021 ctrl
= CMOS_READ(RTC_CONTROL
);
1022 spin_unlock_irq(&rtc_lock
);
1024 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1025 BCD_TO_BIN(year
); /* This should never happen... */
1029 guess
= "SRM (post-2000)";
1030 } else if (year
>= 20 && year
< 48) {
1032 guess
= "ARC console";
1033 } else if (year
>= 48 && year
< 72) {
1035 guess
= "Digital UNIX";
1036 #if defined(__mips__)
1037 } else if (year
>= 72 && year
< 74) {
1039 guess
= "Digital DECstation";
1041 } else if (year
>= 70) {
1043 guess
= "Standard PC (1900)";
1047 printk(KERN_INFO
"rtc: %s epoch (%lu) detected\n", guess
, epoch
);
1050 if (rtc_has_irq
== 0)
1053 init_timer(&rtc_irq_timer
);
1054 rtc_irq_timer
.function
= rtc_dropped_irq
;
1055 spin_lock_irq(&rtc_lock
);
1057 if (!hpet_set_periodic_freq(rtc_freq
)) {
1058 /* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
1059 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT
) & 0xF0) | 0x06), RTC_FREQ_SELECT
);
1061 spin_unlock_irq(&rtc_lock
);
1065 (void) init_sysctl();
1067 printk(KERN_INFO
"Real Time Clock Driver v" RTC_VERSION
"\n");
1072 static void __exit
rtc_exit (void)
1075 remove_proc_entry ("driver/rtc", NULL
);
1076 misc_deregister(&rtc_dev
);
1080 free_irq (rtc_irq
, &rtc_port
);
1082 release_region (RTC_PORT (0), RTC_IO_EXTENT
);
1085 free_irq (RTC_IRQ
, NULL
);
1087 #endif /* __sparc__ */
1090 module_init(rtc_init
);
1091 module_exit(rtc_exit
);
1095 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1096 * (usually during an IDE disk interrupt, with IRQ unmasking off)
1097 * Since the interrupt handler doesn't get called, the IRQ status
1098 * byte doesn't get read, and the RTC stops generating interrupts.
1099 * A timer is set, and will call this function if/when that happens.
1100 * To get it out of this stalled state, we just read the status.
1101 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1102 * (You *really* shouldn't be trying to use a non-realtime system
1103 * for something that requires a steady > 1KHz signal anyways.)
1106 static void rtc_dropped_irq(unsigned long data
)
1110 spin_lock_irq (&rtc_lock
);
1112 if (hpet_rtc_dropped_irq()) {
1113 spin_unlock_irq(&rtc_lock
);
1117 /* Just in case someone disabled the timer from behind our back... */
1118 if (rtc_status
& RTC_TIMER_ON
)
1119 mod_timer(&rtc_irq_timer
, jiffies
+ HZ
/rtc_freq
+ 2*HZ
/100);
1121 rtc_irq_data
+= ((rtc_freq
/HZ
)<<8);
1122 rtc_irq_data
&= ~0xff;
1123 rtc_irq_data
|= (CMOS_READ(RTC_INTR_FLAGS
) & 0xF0); /* restart */
1127 spin_unlock_irq(&rtc_lock
);
1129 printk(KERN_WARNING
"rtc: lost some interrupts at %ldHz.\n", freq
);
1131 /* Now we have new data */
1132 wake_up_interruptible(&rtc_wait
);
1134 kill_fasync (&rtc_async_queue
, SIGIO
, POLL_IN
);
1139 * Info exported via "/proc/driver/rtc".
1142 static int rtc_proc_show(struct seq_file
*seq
, void *v
)
1144 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1145 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1147 unsigned char batt
, ctrl
;
1150 spin_lock_irq(&rtc_lock
);
1151 batt
= CMOS_READ(RTC_VALID
) & RTC_VRT
;
1152 ctrl
= CMOS_READ(RTC_CONTROL
);
1154 spin_unlock_irq(&rtc_lock
);
1157 rtc_get_rtc_time(&tm
);
1160 * There is no way to tell if the luser has the RTC set for local
1161 * time or for Universal Standard Time (GMT). Probably local though.
1164 "rtc_time\t: %02d:%02d:%02d\n"
1165 "rtc_date\t: %04d-%02d-%02d\n"
1166 "rtc_epoch\t: %04lu\n",
1167 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
,
1168 tm
.tm_year
+ 1900, tm
.tm_mon
+ 1, tm
.tm_mday
, epoch
);
1170 get_rtc_alm_time(&tm
);
1173 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1174 * match any value for that particular field. Values that are
1175 * greater than a valid time, but less than 0xc0 shouldn't appear.
1177 seq_puts(seq
, "alarm\t\t: ");
1178 if (tm
.tm_hour
<= 24)
1179 seq_printf(seq
, "%02d:", tm
.tm_hour
);
1181 seq_puts(seq
, "**:");
1183 if (tm
.tm_min
<= 59)
1184 seq_printf(seq
, "%02d:", tm
.tm_min
);
1186 seq_puts(seq
, "**:");
1188 if (tm
.tm_sec
<= 59)
1189 seq_printf(seq
, "%02d\n", tm
.tm_sec
);
1191 seq_puts(seq
, "**\n");
1194 "DST_enable\t: %s\n"
1197 "square_wave\t: %s\n"
1199 "update_IRQ\t: %s\n"
1200 "periodic_IRQ\t: %s\n"
1201 "periodic_freq\t: %ld\n"
1202 "batt_status\t: %s\n",
1211 batt
? "okay" : "dead");
1218 static int rtc_proc_open(struct inode
*inode
, struct file
*file
)
1220 return single_open(file
, rtc_proc_show
, NULL
);
1223 void rtc_get_rtc_time(struct rtc_time
*rtc_tm
)
1225 unsigned long uip_watchdog
= jiffies
;
1227 #ifdef CONFIG_MACH_DECSTATION
1228 unsigned int real_year
;
1232 * read RTC once any update in progress is done. The update
1233 * can take just over 2ms. We wait 20ms. There is no need to
1234 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1235 * If you need to know *exactly* when a second has started, enable
1236 * periodic update complete interrupts, (via ioctl) and then
1237 * immediately read /dev/rtc which will block until you get the IRQ.
1238 * Once the read clears, read the RTC time (again via ioctl). Easy.
1241 while (rtc_is_updating() != 0 && jiffies
- uip_watchdog
< 2*HZ
/100) {
1247 * Only the values that we read from the RTC are set. We leave
1248 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1249 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1250 * only updated by the RTC when initially set to a non-zero value.
1252 spin_lock_irq(&rtc_lock
);
1253 rtc_tm
->tm_sec
= CMOS_READ(RTC_SECONDS
);
1254 rtc_tm
->tm_min
= CMOS_READ(RTC_MINUTES
);
1255 rtc_tm
->tm_hour
= CMOS_READ(RTC_HOURS
);
1256 rtc_tm
->tm_mday
= CMOS_READ(RTC_DAY_OF_MONTH
);
1257 rtc_tm
->tm_mon
= CMOS_READ(RTC_MONTH
);
1258 rtc_tm
->tm_year
= CMOS_READ(RTC_YEAR
);
1259 /* Only set from 2.6.16 onwards */
1260 rtc_tm
->tm_wday
= CMOS_READ(RTC_DAY_OF_WEEK
);
1262 #ifdef CONFIG_MACH_DECSTATION
1263 real_year
= CMOS_READ(RTC_DEC_YEAR
);
1265 ctrl
= CMOS_READ(RTC_CONTROL
);
1266 spin_unlock_irq(&rtc_lock
);
1268 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1270 BCD_TO_BIN(rtc_tm
->tm_sec
);
1271 BCD_TO_BIN(rtc_tm
->tm_min
);
1272 BCD_TO_BIN(rtc_tm
->tm_hour
);
1273 BCD_TO_BIN(rtc_tm
->tm_mday
);
1274 BCD_TO_BIN(rtc_tm
->tm_mon
);
1275 BCD_TO_BIN(rtc_tm
->tm_year
);
1276 BCD_TO_BIN(rtc_tm
->tm_wday
);
1279 #ifdef CONFIG_MACH_DECSTATION
1280 rtc_tm
->tm_year
+= real_year
- 72;
1284 * Account for differences between how the RTC uses the values
1285 * and how they are defined in a struct rtc_time;
1287 if ((rtc_tm
->tm_year
+= (epoch
- 1900)) <= 69)
1288 rtc_tm
->tm_year
+= 100;
1293 static void get_rtc_alm_time(struct rtc_time
*alm_tm
)
1298 * Only the values that we read from the RTC are set. That
1299 * means only tm_hour, tm_min, and tm_sec.
1301 spin_lock_irq(&rtc_lock
);
1302 alm_tm
->tm_sec
= CMOS_READ(RTC_SECONDS_ALARM
);
1303 alm_tm
->tm_min
= CMOS_READ(RTC_MINUTES_ALARM
);
1304 alm_tm
->tm_hour
= CMOS_READ(RTC_HOURS_ALARM
);
1305 ctrl
= CMOS_READ(RTC_CONTROL
);
1306 spin_unlock_irq(&rtc_lock
);
1308 if (!(ctrl
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
)
1310 BCD_TO_BIN(alm_tm
->tm_sec
);
1311 BCD_TO_BIN(alm_tm
->tm_min
);
1312 BCD_TO_BIN(alm_tm
->tm_hour
);
1318 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1319 * Rumour has it that if you frob the interrupt enable/disable
1320 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1321 * ensure you actually start getting interrupts. Probably for
1322 * compatibility with older/broken chipset RTC implementations.
1323 * We also clear out any old irq data after an ioctl() that
1324 * meddles with the interrupt enable/disable bits.
1327 static void mask_rtc_irq_bit_locked(unsigned char bit
)
1331 if (hpet_mask_rtc_irq_bit(bit
))
1333 val
= CMOS_READ(RTC_CONTROL
);
1335 CMOS_WRITE(val
, RTC_CONTROL
);
1336 CMOS_READ(RTC_INTR_FLAGS
);
1341 static void set_rtc_irq_bit_locked(unsigned char bit
)
1345 if (hpet_set_rtc_irq_bit(bit
))
1347 val
= CMOS_READ(RTC_CONTROL
);
1349 CMOS_WRITE(val
, RTC_CONTROL
);
1350 CMOS_READ(RTC_INTR_FLAGS
);
1356 MODULE_AUTHOR("Paul Gortmaker");
1357 MODULE_LICENSE("GPL");
1358 MODULE_ALIAS_MISCDEV(RTC_MINOR
);