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>
91 #include <linux/jiffies.h>
94 static unsigned long rtc_port;
95 static int rtc_irq = PCI_IRQ_NONE;
98 #ifdef CONFIG_HPET_RTC_IRQ
103 static int rtc_has_irq = 1;
106 #ifndef CONFIG_HPET_EMULATE_RTC
107 #define is_hpet_enabled() 0
108 #define hpet_set_alarm_time(hrs, min, sec) 0
109 #define hpet_set_periodic_freq(arg) 0
110 #define hpet_mask_rtc_irq_bit(arg) 0
111 #define hpet_set_rtc_irq_bit(arg) 0
112 #define hpet_rtc_timer_init() do { } while (0)
113 #define hpet_rtc_dropped_irq() 0
114 #define hpet_register_irq_handler(h) ({ 0; })
115 #define hpet_unregister_irq_handler(h) ({ 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; /* 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 * 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[] = {
285 .ctl_name = CTL_UNNUMBERED,
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[] = {
297 .ctl_name = CTL_UNNUMBERED,
305 static ctl_table dev_root[] = {
315 static struct ctl_table_header *sysctl_header;
317 static int __init init_sysctl(void)
319 sysctl_header = register_sysctl_table(dev_root);
323 static void __exit cleanup_sysctl(void)
325 unregister_sysctl_table(sysctl_header);
329 * Now all the various file operations that we export.
332 static ssize_t rtc_read(struct file *file, char __user *buf,
333 size_t count, loff_t *ppos)
338 DECLARE_WAITQUEUE(wait, current);
342 if (rtc_has_irq == 0)
346 * Historically this function used to assume that sizeof(unsigned long)
347 * is the same in userspace and kernelspace. This lead to problems
348 * for configurations with multiple ABIs such a the MIPS o32 and 64
349 * ABIs supported on the same kernel. So now we support read of both
350 * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
353 if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
356 add_wait_queue(&rtc_wait, &wait);
359 /* First make it right. Then make it fast. Putting this whole
360 * block within the parentheses of a while would be too
361 * confusing. And no, xchg() is not the answer. */
363 __set_current_state(TASK_INTERRUPTIBLE);
365 spin_lock_irq(&rtc_lock);
368 spin_unlock_irq(&rtc_lock);
373 if (file->f_flags & O_NONBLOCK) {
377 if (signal_pending(current)) {
378 retval = -ERESTARTSYS;
384 if (count == sizeof(unsigned int)) {
385 retval = put_user(data,
386 (unsigned int __user *)buf) ?: sizeof(int);
388 retval = put_user(data,
389 (unsigned long __user *)buf) ?: sizeof(long);
394 __set_current_state(TASK_RUNNING);
395 remove_wait_queue(&rtc_wait, &wait);
401 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
403 struct rtc_time wtime;
406 if (rtc_has_irq == 0) {
423 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
425 mask_rtc_irq_bit(RTC_AIE);
428 case RTC_AIE_ON: /* Allow alarm interrupts. */
430 set_rtc_irq_bit(RTC_AIE);
433 case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
435 /* can be called from isr via rtc_control() */
438 spin_lock_irqsave(&rtc_lock, flags);
439 mask_rtc_irq_bit_locked(RTC_PIE);
440 if (rtc_status & RTC_TIMER_ON) {
441 rtc_status &= ~RTC_TIMER_ON;
442 del_timer(&rtc_irq_timer);
444 spin_unlock_irqrestore(&rtc_lock, flags);
448 case RTC_PIE_ON: /* Allow periodic ints */
450 /* can be called from isr via rtc_control() */
454 * We don't really want Joe User enabling more
455 * than 64Hz of interrupts on a multi-user machine.
457 if (!kernel && (rtc_freq > rtc_max_user_freq) &&
458 (!capable(CAP_SYS_RESOURCE)))
461 spin_lock_irqsave(&rtc_lock, flags);
462 if (!(rtc_status & RTC_TIMER_ON)) {
463 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq +
465 rtc_status |= RTC_TIMER_ON;
467 set_rtc_irq_bit_locked(RTC_PIE);
468 spin_unlock_irqrestore(&rtc_lock, flags);
472 case RTC_UIE_OFF: /* Mask ints from RTC updates. */
474 mask_rtc_irq_bit(RTC_UIE);
477 case RTC_UIE_ON: /* Allow ints for RTC updates. */
479 set_rtc_irq_bit(RTC_UIE);
483 case RTC_ALM_READ: /* Read the present alarm time */
486 * This returns a struct rtc_time. Reading >= 0xc0
487 * means "don't care" or "match all". Only the tm_hour,
488 * tm_min, and tm_sec values are filled in.
490 memset(&wtime, 0, sizeof(struct rtc_time));
491 get_rtc_alm_time(&wtime);
494 case RTC_ALM_SET: /* Store a time into the alarm */
497 * This expects a struct rtc_time. Writing 0xff means
498 * "don't care" or "match all". Only the tm_hour,
499 * tm_min and tm_sec are used.
501 unsigned char hrs, min, sec;
502 struct rtc_time alm_tm;
504 if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg,
505 sizeof(struct rtc_time)))
508 hrs = alm_tm.tm_hour;
512 spin_lock_irq(&rtc_lock);
513 if (hpet_set_alarm_time(hrs, min, sec)) {
515 * Fallthru and set alarm time in CMOS too,
516 * so that we will get proper value in RTC_ALM_READ
519 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
536 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
537 CMOS_WRITE(min, RTC_MINUTES_ALARM);
538 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
539 spin_unlock_irq(&rtc_lock);
543 case RTC_RD_TIME: /* Read the time/date from RTC */
545 memset(&wtime, 0, sizeof(struct rtc_time));
546 rtc_get_rtc_time(&wtime);
549 case RTC_SET_TIME: /* Set the RTC */
551 struct rtc_time rtc_tm;
552 unsigned char mon, day, hrs, min, sec, leap_yr;
553 unsigned char save_control, save_freq_select;
555 #ifdef CONFIG_MACH_DECSTATION
556 unsigned int real_yrs;
559 if (!capable(CAP_SYS_TIME))
562 if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
563 sizeof(struct rtc_time)))
566 yrs = rtc_tm.tm_year + 1900;
567 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
568 day = rtc_tm.tm_mday;
569 hrs = rtc_tm.tm_hour;
576 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
578 if ((mon > 12) || (day == 0))
581 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
584 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
588 if (yrs > 255) /* They are unsigned */
591 spin_lock_irq(&rtc_lock);
592 #ifdef CONFIG_MACH_DECSTATION
597 * We want to keep the year set to 73 until March
598 * for non-leap years, so that Feb, 29th is handled
601 if (!leap_yr && mon < 3) {
606 /* These limits and adjustments are independent of
607 * whether the chip is in binary mode or not.
610 spin_unlock_irq(&rtc_lock);
616 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
626 save_control = CMOS_READ(RTC_CONTROL);
627 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
628 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
629 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
631 #ifdef CONFIG_MACH_DECSTATION
632 CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
634 CMOS_WRITE(yrs, RTC_YEAR);
635 CMOS_WRITE(mon, RTC_MONTH);
636 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
637 CMOS_WRITE(hrs, RTC_HOURS);
638 CMOS_WRITE(min, RTC_MINUTES);
639 CMOS_WRITE(sec, RTC_SECONDS);
641 CMOS_WRITE(save_control, RTC_CONTROL);
642 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
644 spin_unlock_irq(&rtc_lock);
648 case RTC_IRQP_READ: /* Read the periodic IRQ rate. */
650 return put_user(rtc_freq, (unsigned long __user *)arg);
652 case RTC_IRQP_SET: /* Set periodic IRQ rate. */
656 /* can be called from isr via rtc_control() */
660 * The max we can do is 8192Hz.
662 if ((arg < 2) || (arg > 8192))
665 * We don't really want Joe User generating more
666 * than 64Hz of interrupts on a multi-user machine.
668 if (!kernel && (arg > rtc_max_user_freq) &&
669 !capable(CAP_SYS_RESOURCE))
672 while (arg > (1<<tmp))
676 * Check that the input was really a power of 2.
683 spin_lock_irqsave(&rtc_lock, flags);
684 if (hpet_set_periodic_freq(arg)) {
685 spin_unlock_irqrestore(&rtc_lock, flags);
689 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
691 CMOS_WRITE(val, RTC_FREQ_SELECT);
692 spin_unlock_irqrestore(&rtc_lock, flags);
696 case RTC_EPOCH_READ: /* Read the epoch. */
698 return put_user(epoch, (unsigned long __user *)arg);
700 case RTC_EPOCH_SET: /* Set the epoch. */
703 * There were no RTC clocks before 1900.
708 if (!capable(CAP_SYS_TIME))
717 return copy_to_user((void __user *)arg,
718 &wtime, sizeof wtime) ? -EFAULT : 0;
721 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
724 return rtc_do_ioctl(cmd, arg, 0);
728 * We enforce only one user at a time here with the open/close.
729 * Also clear the previous interrupt data on an open, and clean
730 * up things on a close.
733 /* We use rtc_lock to protect against concurrent opens. So the BKL is not
734 * needed here. Or anywhere else in this driver. */
735 static int rtc_open(struct inode *inode, struct file *file)
737 spin_lock_irq(&rtc_lock);
739 if (rtc_status & RTC_IS_OPEN)
742 rtc_status |= RTC_IS_OPEN;
745 spin_unlock_irq(&rtc_lock);
749 spin_unlock_irq(&rtc_lock);
753 static int rtc_fasync(int fd, struct file *filp, int on)
755 return fasync_helper(fd, filp, on, &rtc_async_queue);
758 static int rtc_release(struct inode *inode, struct file *file)
763 if (rtc_has_irq == 0)
767 * Turn off all interrupts once the device is no longer
768 * in use, and clear the data.
771 spin_lock_irq(&rtc_lock);
772 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
773 tmp = CMOS_READ(RTC_CONTROL);
777 CMOS_WRITE(tmp, RTC_CONTROL);
778 CMOS_READ(RTC_INTR_FLAGS);
780 if (rtc_status & RTC_TIMER_ON) {
781 rtc_status &= ~RTC_TIMER_ON;
782 del_timer(&rtc_irq_timer);
784 spin_unlock_irq(&rtc_lock);
786 if (file->f_flags & FASYNC)
787 rtc_fasync(-1, file, 0);
791 spin_lock_irq(&rtc_lock);
793 rtc_status &= ~RTC_IS_OPEN;
794 spin_unlock_irq(&rtc_lock);
800 /* Called without the kernel lock - fine */
801 static unsigned int rtc_poll(struct file *file, poll_table *wait)
805 if (rtc_has_irq == 0)
808 poll_wait(file, &rtc_wait, wait);
810 spin_lock_irq(&rtc_lock);
812 spin_unlock_irq(&rtc_lock);
815 return POLLIN | POLLRDNORM;
820 int rtc_register(rtc_task_t *task)
825 if (task == NULL || task->func == NULL)
827 spin_lock_irq(&rtc_lock);
828 if (rtc_status & RTC_IS_OPEN) {
829 spin_unlock_irq(&rtc_lock);
832 spin_lock(&rtc_task_lock);
834 spin_unlock(&rtc_task_lock);
835 spin_unlock_irq(&rtc_lock);
838 rtc_status |= RTC_IS_OPEN;
840 spin_unlock(&rtc_task_lock);
841 spin_unlock_irq(&rtc_lock);
845 EXPORT_SYMBOL(rtc_register);
847 int rtc_unregister(rtc_task_t *task)
854 spin_lock_irq(&rtc_lock);
855 spin_lock(&rtc_task_lock);
856 if (rtc_callback != task) {
857 spin_unlock(&rtc_task_lock);
858 spin_unlock_irq(&rtc_lock);
863 /* disable controls */
864 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
865 tmp = CMOS_READ(RTC_CONTROL);
869 CMOS_WRITE(tmp, RTC_CONTROL);
870 CMOS_READ(RTC_INTR_FLAGS);
872 if (rtc_status & RTC_TIMER_ON) {
873 rtc_status &= ~RTC_TIMER_ON;
874 del_timer(&rtc_irq_timer);
876 rtc_status &= ~RTC_IS_OPEN;
877 spin_unlock(&rtc_task_lock);
878 spin_unlock_irq(&rtc_lock);
882 EXPORT_SYMBOL(rtc_unregister);
884 int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
890 if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET)
892 spin_lock_irqsave(&rtc_task_lock, flags);
893 if (rtc_callback != task) {
894 spin_unlock_irqrestore(&rtc_task_lock, flags);
897 spin_unlock_irqrestore(&rtc_task_lock, flags);
898 return rtc_do_ioctl(cmd, arg, 1);
901 EXPORT_SYMBOL(rtc_control);
904 * The various file operations we support.
907 static const struct file_operations rtc_fops = {
908 .owner = THIS_MODULE,
916 .release = rtc_release,
917 .fasync = rtc_fasync,
920 static struct miscdevice rtc_dev = {
926 #ifdef CONFIG_PROC_FS
927 static const struct file_operations rtc_proc_fops = {
928 .owner = THIS_MODULE,
929 .open = rtc_proc_open,
932 .release = single_release,
936 static resource_size_t rtc_size;
938 static struct resource * __init rtc_request_region(resource_size_t size)
943 r = request_region(RTC_PORT(0), size, "rtc");
945 r = request_mem_region(RTC_PORT(0), size, "rtc");
953 static void rtc_release_region(void)
956 release_region(RTC_PORT(0), rtc_size);
958 release_mem_region(RTC_PORT(0), rtc_size);
961 static int __init rtc_init(void)
963 #ifdef CONFIG_PROC_FS
964 struct proc_dir_entry *ent;
966 #if defined(__alpha__) || defined(__mips__)
967 unsigned int year, ctrl;
970 #ifdef CONFIG_SPARC32
971 struct linux_ebus *ebus;
972 struct linux_ebus_device *edev;
976 irq_handler_t rtc_int_handler_ptr;
980 #ifdef CONFIG_SPARC32
981 for_each_ebus(ebus) {
982 for_each_ebusdev(edev, ebus) {
983 if (strcmp(edev->prom_node->name, "rtc") == 0) {
984 rtc_port = edev->resource[0].start;
985 rtc_irq = edev->irqs[0];
991 printk(KERN_ERR "rtc_init: no PC rtc found\n");
995 if (rtc_irq == PCI_IRQ_NONE) {
1001 * XXX Interrupt pin #7 in Espresso is shared between RTC and
1002 * PCI Slot 2 INTA# (and some INTx# in Slot 1).
1004 if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc",
1005 (void *)&rtc_port)) {
1007 printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
1012 r = rtc_request_region(RTC_IO_EXTENT);
1015 * If we've already requested a smaller range (for example, because
1016 * PNPBIOS or ACPI told us how the device is configured), the request
1017 * above might fail because it's too big.
1019 * If so, request just the range we actually use.
1022 r = rtc_request_region(RTC_IO_EXTENT_USED);
1027 printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
1028 (long)(RTC_PORT(0)));
1033 if (is_hpet_enabled()) {
1036 rtc_int_handler_ptr = hpet_rtc_interrupt;
1037 err = hpet_register_irq_handler(rtc_interrupt);
1039 printk(KERN_WARNING "hpet_register_irq_handler failed "
1044 rtc_int_handler_ptr = rtc_interrupt;
1047 if (request_irq(RTC_IRQ, rtc_int_handler_ptr, IRQF_DISABLED,
1049 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
1051 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
1052 rtc_release_region();
1056 hpet_rtc_timer_init();
1060 #endif /* CONFIG_SPARC32 vs. others */
1062 if (misc_register(&rtc_dev)) {
1064 free_irq(RTC_IRQ, NULL);
1065 hpet_unregister_irq_handler(rtc_interrupt);
1068 rtc_release_region();
1072 #ifdef CONFIG_PROC_FS
1073 ent = proc_create("driver/rtc", 0, NULL, &rtc_proc_fops);
1075 printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
1078 #if defined(__alpha__) || defined(__mips__)
1081 /* Each operating system on an Alpha uses its own epoch.
1082 Let's try to guess which one we are using now. */
1084 if (rtc_is_updating() != 0)
1087 spin_lock_irq(&rtc_lock);
1088 year = CMOS_READ(RTC_YEAR);
1089 ctrl = CMOS_READ(RTC_CONTROL);
1090 spin_unlock_irq(&rtc_lock);
1092 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1093 BCD_TO_BIN(year); /* This should never happen... */
1097 guess = "SRM (post-2000)";
1098 } else if (year >= 20 && year < 48) {
1100 guess = "ARC console";
1101 } else if (year >= 48 && year < 72) {
1103 guess = "Digital UNIX";
1104 #if defined(__mips__)
1105 } else if (year >= 72 && year < 74) {
1107 guess = "Digital DECstation";
1109 } else if (year >= 70) {
1111 guess = "Standard PC (1900)";
1115 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n",
1119 if (rtc_has_irq == 0)
1122 spin_lock_irq(&rtc_lock);
1124 if (!hpet_set_periodic_freq(rtc_freq)) {
1126 * Initialize periodic frequency to CMOS reset default,
1129 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06),
1132 spin_unlock_irq(&rtc_lock);
1136 (void) init_sysctl();
1138 printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
1143 static void __exit rtc_exit(void)
1146 remove_proc_entry("driver/rtc", NULL);
1147 misc_deregister(&rtc_dev);
1149 #ifdef CONFIG_SPARC32
1151 free_irq(rtc_irq, &rtc_port);
1153 rtc_release_region();
1156 free_irq(RTC_IRQ, NULL);
1157 hpet_unregister_irq_handler(hpet_rtc_interrupt);
1160 #endif /* CONFIG_SPARC32 */
1163 module_init(rtc_init);
1164 module_exit(rtc_exit);
1168 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1169 * (usually during an IDE disk interrupt, with IRQ unmasking off)
1170 * Since the interrupt handler doesn't get called, the IRQ status
1171 * byte doesn't get read, and the RTC stops generating interrupts.
1172 * A timer is set, and will call this function if/when that happens.
1173 * To get it out of this stalled state, we just read the status.
1174 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1175 * (You *really* shouldn't be trying to use a non-realtime system
1176 * for something that requires a steady > 1KHz signal anyways.)
1179 static void rtc_dropped_irq(unsigned long data)
1183 spin_lock_irq(&rtc_lock);
1185 if (hpet_rtc_dropped_irq()) {
1186 spin_unlock_irq(&rtc_lock);
1190 /* Just in case someone disabled the timer from behind our back... */
1191 if (rtc_status & RTC_TIMER_ON)
1192 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
1194 rtc_irq_data += ((rtc_freq/HZ)<<8);
1195 rtc_irq_data &= ~0xff;
1196 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */
1200 spin_unlock_irq(&rtc_lock);
1202 if (printk_ratelimit()) {
1203 printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
1207 /* Now we have new data */
1208 wake_up_interruptible(&rtc_wait);
1210 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
1214 #ifdef CONFIG_PROC_FS
1216 * Info exported via "/proc/driver/rtc".
1219 static int rtc_proc_show(struct seq_file *seq, void *v)
1221 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1222 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1224 unsigned char batt, ctrl;
1227 spin_lock_irq(&rtc_lock);
1228 batt = CMOS_READ(RTC_VALID) & RTC_VRT;
1229 ctrl = CMOS_READ(RTC_CONTROL);
1231 spin_unlock_irq(&rtc_lock);
1234 rtc_get_rtc_time(&tm);
1237 * There is no way to tell if the luser has the RTC set for local
1238 * time or for Universal Standard Time (GMT). Probably local though.
1241 "rtc_time\t: %02d:%02d:%02d\n"
1242 "rtc_date\t: %04d-%02d-%02d\n"
1243 "rtc_epoch\t: %04lu\n",
1244 tm.tm_hour, tm.tm_min, tm.tm_sec,
1245 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
1247 get_rtc_alm_time(&tm);
1250 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1251 * match any value for that particular field. Values that are
1252 * greater than a valid time, but less than 0xc0 shouldn't appear.
1254 seq_puts(seq, "alarm\t\t: ");
1255 if (tm.tm_hour <= 24)
1256 seq_printf(seq, "%02d:", tm.tm_hour);
1258 seq_puts(seq, "**:");
1260 if (tm.tm_min <= 59)
1261 seq_printf(seq, "%02d:", tm.tm_min);
1263 seq_puts(seq, "**:");
1265 if (tm.tm_sec <= 59)
1266 seq_printf(seq, "%02d\n", tm.tm_sec);
1268 seq_puts(seq, "**\n");
1271 "DST_enable\t: %s\n"
1274 "square_wave\t: %s\n"
1276 "update_IRQ\t: %s\n"
1277 "periodic_IRQ\t: %s\n"
1278 "periodic_freq\t: %ld\n"
1279 "batt_status\t: %s\n",
1288 batt ? "okay" : "dead");
1295 static int rtc_proc_open(struct inode *inode, struct file *file)
1297 return single_open(file, rtc_proc_show, NULL);
1301 void rtc_get_rtc_time(struct rtc_time *rtc_tm)
1303 unsigned long uip_watchdog = jiffies, flags;
1305 #ifdef CONFIG_MACH_DECSTATION
1306 unsigned int real_year;
1310 * read RTC once any update in progress is done. The update
1311 * can take just over 2ms. We wait 20ms. There is no need to
1312 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1313 * If you need to know *exactly* when a second has started, enable
1314 * periodic update complete interrupts, (via ioctl) and then
1315 * immediately read /dev/rtc which will block until you get the IRQ.
1316 * Once the read clears, read the RTC time (again via ioctl). Easy.
1319 while (rtc_is_updating() != 0 &&
1320 time_before(jiffies, uip_watchdog + 2*HZ/100))
1324 * Only the values that we read from the RTC are set. We leave
1325 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1326 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1327 * only updated by the RTC when initially set to a non-zero value.
1329 spin_lock_irqsave(&rtc_lock, flags);
1330 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
1331 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
1332 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
1333 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
1334 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
1335 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
1336 /* Only set from 2.6.16 onwards */
1337 rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);
1339 #ifdef CONFIG_MACH_DECSTATION
1340 real_year = CMOS_READ(RTC_DEC_YEAR);
1342 ctrl = CMOS_READ(RTC_CONTROL);
1343 spin_unlock_irqrestore(&rtc_lock, flags);
1345 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1346 BCD_TO_BIN(rtc_tm->tm_sec);
1347 BCD_TO_BIN(rtc_tm->tm_min);
1348 BCD_TO_BIN(rtc_tm->tm_hour);
1349 BCD_TO_BIN(rtc_tm->tm_mday);
1350 BCD_TO_BIN(rtc_tm->tm_mon);
1351 BCD_TO_BIN(rtc_tm->tm_year);
1352 BCD_TO_BIN(rtc_tm->tm_wday);
1355 #ifdef CONFIG_MACH_DECSTATION
1356 rtc_tm->tm_year += real_year - 72;
1360 * Account for differences between how the RTC uses the values
1361 * and how they are defined in a struct rtc_time;
1363 rtc_tm->tm_year += epoch - 1900;
1364 if (rtc_tm->tm_year <= 69)
1365 rtc_tm->tm_year += 100;
1370 static void get_rtc_alm_time(struct rtc_time *alm_tm)
1375 * Only the values that we read from the RTC are set. That
1376 * means only tm_hour, tm_min, and tm_sec.
1378 spin_lock_irq(&rtc_lock);
1379 alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
1380 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
1381 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
1382 ctrl = CMOS_READ(RTC_CONTROL);
1383 spin_unlock_irq(&rtc_lock);
1385 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1386 BCD_TO_BIN(alm_tm->tm_sec);
1387 BCD_TO_BIN(alm_tm->tm_min);
1388 BCD_TO_BIN(alm_tm->tm_hour);
1394 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1395 * Rumour has it that if you frob the interrupt enable/disable
1396 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1397 * ensure you actually start getting interrupts. Probably for
1398 * compatibility with older/broken chipset RTC implementations.
1399 * We also clear out any old irq data after an ioctl() that
1400 * meddles with the interrupt enable/disable bits.
1403 static void mask_rtc_irq_bit_locked(unsigned char bit)
1407 if (hpet_mask_rtc_irq_bit(bit))
1409 val = CMOS_READ(RTC_CONTROL);
1411 CMOS_WRITE(val, RTC_CONTROL);
1412 CMOS_READ(RTC_INTR_FLAGS);
1417 static void set_rtc_irq_bit_locked(unsigned char bit)
1421 if (hpet_set_rtc_irq_bit(bit))
1423 val = CMOS_READ(RTC_CONTROL);
1425 CMOS_WRITE(val, RTC_CONTROL);
1426 CMOS_READ(RTC_INTR_FLAGS);
1432 MODULE_AUTHOR("Paul Gortmaker");
1433 MODULE_LICENSE("GPL");
1434 MODULE_ALIAS_MISCDEV(RTC_MINOR);