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/smp_lock.h>
77 #include <linux/sysctl.h>
78 #include <linux/wait.h>
79 #include <linux/bcd.h>
80 #include <linux/delay.h>
81 #include <linux/smp_lock.h>
82 #include <linux/uaccess.h>
84 #include <asm/current.h>
85 #include <asm/system.h>
92 #include <linux/pci.h>
93 #include <linux/jiffies.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
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)
125 extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);
129 * We sponge a minor off of the misc major. No need slurping
130 * up another valuable major dev number for this. If you add
131 * an ioctl, make sure you don't conflict with SPARC's RTC
135 static struct fasync_struct *rtc_async_queue;
137 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
140 static void rtc_dropped_irq(unsigned long data);
142 static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq, 0, 0);
145 static ssize_t rtc_read(struct file *file, char __user *buf,
146 size_t count, loff_t *ppos);
148 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
151 static unsigned int rtc_poll(struct file *file, poll_table *wait);
154 static void get_rtc_alm_time(struct rtc_time *alm_tm);
156 static void set_rtc_irq_bit_locked(unsigned char bit);
157 static void mask_rtc_irq_bit_locked(unsigned char bit);
159 static inline void set_rtc_irq_bit(unsigned char bit)
161 spin_lock_irq(&rtc_lock);
162 set_rtc_irq_bit_locked(bit);
163 spin_unlock_irq(&rtc_lock);
166 static void mask_rtc_irq_bit(unsigned char bit)
168 spin_lock_irq(&rtc_lock);
169 mask_rtc_irq_bit_locked(bit);
170 spin_unlock_irq(&rtc_lock);
174 #ifdef CONFIG_PROC_FS
175 static int rtc_proc_open(struct inode *inode, struct file *file);
179 * Bits in rtc_status. (6 bits of room for future expansion)
182 #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
183 #define RTC_TIMER_ON 0x02 /* missed irq timer active */
186 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
187 * protected by the big kernel lock. However, ioctl can still disable the timer
188 * in rtc_status and then with del_timer after the interrupt has read
189 * rtc_status but before mod_timer is called, which would then reenable the
190 * timer (but you would need to have an awful timing before you'd trip on it)
192 static unsigned long rtc_status; /* bitmapped status byte. */
193 static unsigned long rtc_freq; /* Current periodic IRQ rate */
194 static unsigned long rtc_irq_data; /* our output to the world */
195 static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */
199 * rtc_task_lock nests inside rtc_lock.
201 static DEFINE_SPINLOCK(rtc_task_lock);
202 static rtc_task_t *rtc_callback;
206 * If this driver ever becomes modularised, it will be really nice
207 * to make the epoch retain its value across module reload...
210 static unsigned long epoch = 1900; /* year corresponding to 0x00 */
212 static const unsigned char days_in_mo[] =
213 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
216 * Returns true if a clock update is in progress
218 static inline unsigned char rtc_is_updating(void)
223 spin_lock_irqsave(&rtc_lock, flags);
224 uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
225 spin_unlock_irqrestore(&rtc_lock, flags);
231 * A very tiny interrupt handler. It runs with IRQF_DISABLED set,
232 * but there is possibility of conflicting with the set_rtc_mmss()
233 * call (the rtc irq and the timer irq can easily run at the same
234 * time in two different CPUs). So we need to serialize
235 * accesses to the chip with the rtc_lock spinlock that each
236 * architecture should implement in the timer code.
237 * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
240 irqreturn_t rtc_interrupt(int irq, void *dev_id)
243 * Can be an alarm interrupt, update complete interrupt,
244 * or a periodic interrupt. We store the status in the
245 * low byte and the number of interrupts received since
246 * the last read in the remainder of rtc_irq_data.
249 spin_lock(&rtc_lock);
250 rtc_irq_data += 0x100;
251 rtc_irq_data &= ~0xff;
252 if (is_hpet_enabled()) {
254 * In this case it is HPET RTC interrupt handler
255 * calling us, with the interrupt information
256 * passed as arg1, instead of irq.
258 rtc_irq_data |= (unsigned long)irq & 0xF0;
260 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
263 if (rtc_status & RTC_TIMER_ON)
264 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
266 spin_unlock(&rtc_lock);
268 /* Now do the rest of the actions */
269 spin_lock(&rtc_task_lock);
271 rtc_callback->func(rtc_callback->private_data);
272 spin_unlock(&rtc_task_lock);
273 wake_up_interruptible(&rtc_wait);
275 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
282 * sysctl-tuning infrastructure.
284 static ctl_table rtc_table[] = {
286 .ctl_name = CTL_UNNUMBERED,
287 .procname = "max-user-freq",
288 .data = &rtc_max_user_freq,
289 .maxlen = sizeof(int),
291 .proc_handler = &proc_dointvec,
296 static ctl_table rtc_root[] = {
298 .ctl_name = CTL_UNNUMBERED,
306 static ctl_table dev_root[] = {
316 static struct ctl_table_header *sysctl_header;
318 static int __init init_sysctl(void)
320 sysctl_header = register_sysctl_table(dev_root);
324 static void __exit cleanup_sysctl(void)
326 unregister_sysctl_table(sysctl_header);
330 * Now all the various file operations that we export.
333 static ssize_t rtc_read(struct file *file, char __user *buf,
334 size_t count, loff_t *ppos)
339 DECLARE_WAITQUEUE(wait, current);
343 if (rtc_has_irq == 0)
347 * Historically this function used to assume that sizeof(unsigned long)
348 * is the same in userspace and kernelspace. This lead to problems
349 * for configurations with multiple ABIs such a the MIPS o32 and 64
350 * ABIs supported on the same kernel. So now we support read of both
351 * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
354 if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
357 add_wait_queue(&rtc_wait, &wait);
360 /* First make it right. Then make it fast. Putting this whole
361 * block within the parentheses of a while would be too
362 * confusing. And no, xchg() is not the answer. */
364 __set_current_state(TASK_INTERRUPTIBLE);
366 spin_lock_irq(&rtc_lock);
369 spin_unlock_irq(&rtc_lock);
374 if (file->f_flags & O_NONBLOCK) {
378 if (signal_pending(current)) {
379 retval = -ERESTARTSYS;
385 if (count == sizeof(unsigned int)) {
386 retval = put_user(data,
387 (unsigned int __user *)buf) ?: sizeof(int);
389 retval = put_user(data,
390 (unsigned long __user *)buf) ?: sizeof(long);
395 __set_current_state(TASK_RUNNING);
396 remove_wait_queue(&rtc_wait, &wait);
402 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
404 struct rtc_time wtime;
407 if (rtc_has_irq == 0) {
424 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
426 mask_rtc_irq_bit(RTC_AIE);
429 case RTC_AIE_ON: /* Allow alarm interrupts. */
431 set_rtc_irq_bit(RTC_AIE);
434 case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
436 /* can be called from isr via rtc_control() */
439 spin_lock_irqsave(&rtc_lock, flags);
440 mask_rtc_irq_bit_locked(RTC_PIE);
441 if (rtc_status & RTC_TIMER_ON) {
442 rtc_status &= ~RTC_TIMER_ON;
443 del_timer(&rtc_irq_timer);
445 spin_unlock_irqrestore(&rtc_lock, flags);
449 case RTC_PIE_ON: /* Allow periodic ints */
451 /* can be called from isr via rtc_control() */
455 * We don't really want Joe User enabling more
456 * than 64Hz of interrupts on a multi-user machine.
458 if (!kernel && (rtc_freq > rtc_max_user_freq) &&
459 (!capable(CAP_SYS_RESOURCE)))
462 spin_lock_irqsave(&rtc_lock, flags);
463 if (!(rtc_status & RTC_TIMER_ON)) {
464 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq +
466 rtc_status |= RTC_TIMER_ON;
468 set_rtc_irq_bit_locked(RTC_PIE);
469 spin_unlock_irqrestore(&rtc_lock, flags);
473 case RTC_UIE_OFF: /* Mask ints from RTC updates. */
475 mask_rtc_irq_bit(RTC_UIE);
478 case RTC_UIE_ON: /* Allow ints for RTC updates. */
480 set_rtc_irq_bit(RTC_UIE);
484 case RTC_ALM_READ: /* Read the present alarm time */
487 * This returns a struct rtc_time. Reading >= 0xc0
488 * means "don't care" or "match all". Only the tm_hour,
489 * tm_min, and tm_sec values are filled in.
491 memset(&wtime, 0, sizeof(struct rtc_time));
492 get_rtc_alm_time(&wtime);
495 case RTC_ALM_SET: /* Store a time into the alarm */
498 * This expects a struct rtc_time. Writing 0xff means
499 * "don't care" or "match all". Only the tm_hour,
500 * tm_min and tm_sec are used.
502 unsigned char hrs, min, sec;
503 struct rtc_time alm_tm;
505 if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg,
506 sizeof(struct rtc_time)))
509 hrs = alm_tm.tm_hour;
513 spin_lock_irq(&rtc_lock);
514 if (hpet_set_alarm_time(hrs, min, sec)) {
516 * Fallthru and set alarm time in CMOS too,
517 * so that we will get proper value in RTC_ALM_READ
520 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
537 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
538 CMOS_WRITE(min, RTC_MINUTES_ALARM);
539 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
540 spin_unlock_irq(&rtc_lock);
544 case RTC_RD_TIME: /* Read the time/date from RTC */
546 memset(&wtime, 0, sizeof(struct rtc_time));
547 rtc_get_rtc_time(&wtime);
550 case RTC_SET_TIME: /* Set the RTC */
552 struct rtc_time rtc_tm;
553 unsigned char mon, day, hrs, min, sec, leap_yr;
554 unsigned char save_control, save_freq_select;
556 #ifdef CONFIG_MACH_DECSTATION
557 unsigned int real_yrs;
560 if (!capable(CAP_SYS_TIME))
563 if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
564 sizeof(struct rtc_time)))
567 yrs = rtc_tm.tm_year + 1900;
568 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
569 day = rtc_tm.tm_mday;
570 hrs = rtc_tm.tm_hour;
577 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
579 if ((mon > 12) || (day == 0))
582 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
585 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
589 if (yrs > 255) /* They are unsigned */
592 spin_lock_irq(&rtc_lock);
593 #ifdef CONFIG_MACH_DECSTATION
598 * We want to keep the year set to 73 until March
599 * for non-leap years, so that Feb, 29th is handled
602 if (!leap_yr && mon < 3) {
607 /* These limits and adjustments are independent of
608 * whether the chip is in binary mode or not.
611 spin_unlock_irq(&rtc_lock);
617 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
627 save_control = CMOS_READ(RTC_CONTROL);
628 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
629 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
630 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
632 #ifdef CONFIG_MACH_DECSTATION
633 CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
635 CMOS_WRITE(yrs, RTC_YEAR);
636 CMOS_WRITE(mon, RTC_MONTH);
637 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
638 CMOS_WRITE(hrs, RTC_HOURS);
639 CMOS_WRITE(min, RTC_MINUTES);
640 CMOS_WRITE(sec, RTC_SECONDS);
642 CMOS_WRITE(save_control, RTC_CONTROL);
643 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
645 spin_unlock_irq(&rtc_lock);
649 case RTC_IRQP_READ: /* Read the periodic IRQ rate. */
651 return put_user(rtc_freq, (unsigned long __user *)arg);
653 case RTC_IRQP_SET: /* Set periodic IRQ rate. */
657 /* can be called from isr via rtc_control() */
661 * The max we can do is 8192Hz.
663 if ((arg < 2) || (arg > 8192))
666 * We don't really want Joe User generating more
667 * than 64Hz of interrupts on a multi-user machine.
669 if (!kernel && (arg > rtc_max_user_freq) &&
670 !capable(CAP_SYS_RESOURCE))
673 while (arg > (1<<tmp))
677 * Check that the input was really a power of 2.
684 spin_lock_irqsave(&rtc_lock, flags);
685 if (hpet_set_periodic_freq(arg)) {
686 spin_unlock_irqrestore(&rtc_lock, flags);
690 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
692 CMOS_WRITE(val, RTC_FREQ_SELECT);
693 spin_unlock_irqrestore(&rtc_lock, flags);
697 case RTC_EPOCH_READ: /* Read the epoch. */
699 return put_user(epoch, (unsigned long __user *)arg);
701 case RTC_EPOCH_SET: /* Set the epoch. */
704 * There were no RTC clocks before 1900.
709 if (!capable(CAP_SYS_TIME))
718 return copy_to_user((void __user *)arg,
719 &wtime, sizeof wtime) ? -EFAULT : 0;
722 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
726 ret = rtc_do_ioctl(cmd, arg, 0);
732 * We enforce only one user at a time here with the open/close.
733 * Also clear the previous interrupt data on an open, and clean
734 * up things on a close.
737 /* We use rtc_lock to protect against concurrent opens. So the BKL is not
738 * needed here. Or anywhere else in this driver. */
739 static int rtc_open(struct inode *inode, struct file *file)
742 spin_lock_irq(&rtc_lock);
744 if (rtc_status & RTC_IS_OPEN)
747 rtc_status |= RTC_IS_OPEN;
750 spin_unlock_irq(&rtc_lock);
755 spin_unlock_irq(&rtc_lock);
760 static int rtc_fasync(int fd, struct file *filp, int on)
762 return fasync_helper(fd, filp, on, &rtc_async_queue);
765 static int rtc_release(struct inode *inode, struct file *file)
770 if (rtc_has_irq == 0)
774 * Turn off all interrupts once the device is no longer
775 * in use, and clear the data.
778 spin_lock_irq(&rtc_lock);
779 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
780 tmp = CMOS_READ(RTC_CONTROL);
784 CMOS_WRITE(tmp, RTC_CONTROL);
785 CMOS_READ(RTC_INTR_FLAGS);
787 if (rtc_status & RTC_TIMER_ON) {
788 rtc_status &= ~RTC_TIMER_ON;
789 del_timer(&rtc_irq_timer);
791 spin_unlock_irq(&rtc_lock);
793 if (file->f_flags & FASYNC)
794 rtc_fasync(-1, file, 0);
798 spin_lock_irq(&rtc_lock);
800 rtc_status &= ~RTC_IS_OPEN;
801 spin_unlock_irq(&rtc_lock);
807 /* Called without the kernel lock - fine */
808 static unsigned int rtc_poll(struct file *file, poll_table *wait)
812 if (rtc_has_irq == 0)
815 poll_wait(file, &rtc_wait, wait);
817 spin_lock_irq(&rtc_lock);
819 spin_unlock_irq(&rtc_lock);
822 return POLLIN | POLLRDNORM;
827 int rtc_register(rtc_task_t *task)
832 if (task == NULL || task->func == NULL)
834 spin_lock_irq(&rtc_lock);
835 if (rtc_status & RTC_IS_OPEN) {
836 spin_unlock_irq(&rtc_lock);
839 spin_lock(&rtc_task_lock);
841 spin_unlock(&rtc_task_lock);
842 spin_unlock_irq(&rtc_lock);
845 rtc_status |= RTC_IS_OPEN;
847 spin_unlock(&rtc_task_lock);
848 spin_unlock_irq(&rtc_lock);
852 EXPORT_SYMBOL(rtc_register);
854 int rtc_unregister(rtc_task_t *task)
861 spin_lock_irq(&rtc_lock);
862 spin_lock(&rtc_task_lock);
863 if (rtc_callback != task) {
864 spin_unlock(&rtc_task_lock);
865 spin_unlock_irq(&rtc_lock);
870 /* disable controls */
871 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
872 tmp = CMOS_READ(RTC_CONTROL);
876 CMOS_WRITE(tmp, RTC_CONTROL);
877 CMOS_READ(RTC_INTR_FLAGS);
879 if (rtc_status & RTC_TIMER_ON) {
880 rtc_status &= ~RTC_TIMER_ON;
881 del_timer(&rtc_irq_timer);
883 rtc_status &= ~RTC_IS_OPEN;
884 spin_unlock(&rtc_task_lock);
885 spin_unlock_irq(&rtc_lock);
889 EXPORT_SYMBOL(rtc_unregister);
891 int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
897 if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET)
899 spin_lock_irqsave(&rtc_task_lock, flags);
900 if (rtc_callback != task) {
901 spin_unlock_irqrestore(&rtc_task_lock, flags);
904 spin_unlock_irqrestore(&rtc_task_lock, flags);
905 return rtc_do_ioctl(cmd, arg, 1);
908 EXPORT_SYMBOL(rtc_control);
911 * The various file operations we support.
914 static const struct file_operations rtc_fops = {
915 .owner = THIS_MODULE,
921 .unlocked_ioctl = rtc_ioctl,
923 .release = rtc_release,
924 .fasync = rtc_fasync,
927 static struct miscdevice rtc_dev = {
933 #ifdef CONFIG_PROC_FS
934 static const struct file_operations rtc_proc_fops = {
935 .owner = THIS_MODULE,
936 .open = rtc_proc_open,
939 .release = single_release,
943 static resource_size_t rtc_size;
945 static struct resource * __init rtc_request_region(resource_size_t size)
950 r = request_region(RTC_PORT(0), size, "rtc");
952 r = request_mem_region(RTC_PORT(0), size, "rtc");
960 static void rtc_release_region(void)
963 release_region(RTC_PORT(0), rtc_size);
965 release_mem_region(RTC_PORT(0), rtc_size);
968 static int __init rtc_init(void)
970 #ifdef CONFIG_PROC_FS
971 struct proc_dir_entry *ent;
973 #if defined(__alpha__) || defined(__mips__)
974 unsigned int year, ctrl;
977 #ifdef CONFIG_SPARC32
978 struct linux_ebus *ebus;
979 struct linux_ebus_device *edev;
983 irq_handler_t rtc_int_handler_ptr;
987 #ifdef CONFIG_SPARC32
988 for_each_ebus(ebus) {
989 for_each_ebusdev(edev, ebus) {
990 if (strcmp(edev->prom_node->name, "rtc") == 0) {
991 rtc_port = edev->resource[0].start;
992 rtc_irq = edev->irqs[0];
998 printk(KERN_ERR "rtc_init: no PC rtc found\n");
1002 if (rtc_irq == PCI_IRQ_NONE) {
1008 * XXX Interrupt pin #7 in Espresso is shared between RTC and
1009 * PCI Slot 2 INTA# (and some INTx# in Slot 1).
1011 if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc",
1012 (void *)&rtc_port)) {
1014 printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
1019 r = rtc_request_region(RTC_IO_EXTENT);
1022 * If we've already requested a smaller range (for example, because
1023 * PNPBIOS or ACPI told us how the device is configured), the request
1024 * above might fail because it's too big.
1026 * If so, request just the range we actually use.
1029 r = rtc_request_region(RTC_IO_EXTENT_USED);
1034 printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
1035 (long)(RTC_PORT(0)));
1040 if (is_hpet_enabled()) {
1043 rtc_int_handler_ptr = hpet_rtc_interrupt;
1044 err = hpet_register_irq_handler(rtc_interrupt);
1046 printk(KERN_WARNING "hpet_register_irq_handler failed "
1051 rtc_int_handler_ptr = rtc_interrupt;
1054 if (request_irq(RTC_IRQ, rtc_int_handler_ptr, IRQF_DISABLED,
1056 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
1058 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
1059 rtc_release_region();
1063 hpet_rtc_timer_init();
1067 #endif /* CONFIG_SPARC32 vs. others */
1069 if (misc_register(&rtc_dev)) {
1071 free_irq(RTC_IRQ, NULL);
1072 hpet_unregister_irq_handler(rtc_interrupt);
1075 rtc_release_region();
1079 #ifdef CONFIG_PROC_FS
1080 ent = proc_create("driver/rtc", 0, NULL, &rtc_proc_fops);
1082 printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
1085 #if defined(__alpha__) || defined(__mips__)
1088 /* Each operating system on an Alpha uses its own epoch.
1089 Let's try to guess which one we are using now. */
1091 if (rtc_is_updating() != 0)
1094 spin_lock_irq(&rtc_lock);
1095 year = CMOS_READ(RTC_YEAR);
1096 ctrl = CMOS_READ(RTC_CONTROL);
1097 spin_unlock_irq(&rtc_lock);
1099 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1100 BCD_TO_BIN(year); /* This should never happen... */
1104 guess = "SRM (post-2000)";
1105 } else if (year >= 20 && year < 48) {
1107 guess = "ARC console";
1108 } else if (year >= 48 && year < 72) {
1110 guess = "Digital UNIX";
1111 #if defined(__mips__)
1112 } else if (year >= 72 && year < 74) {
1114 guess = "Digital DECstation";
1116 } else if (year >= 70) {
1118 guess = "Standard PC (1900)";
1122 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n",
1126 if (rtc_has_irq == 0)
1129 spin_lock_irq(&rtc_lock);
1131 if (!hpet_set_periodic_freq(rtc_freq)) {
1133 * Initialize periodic frequency to CMOS reset default,
1136 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06),
1139 spin_unlock_irq(&rtc_lock);
1143 (void) init_sysctl();
1145 printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
1150 static void __exit rtc_exit(void)
1153 remove_proc_entry("driver/rtc", NULL);
1154 misc_deregister(&rtc_dev);
1156 #ifdef CONFIG_SPARC32
1158 free_irq(rtc_irq, &rtc_port);
1160 rtc_release_region();
1163 free_irq(RTC_IRQ, NULL);
1164 hpet_unregister_irq_handler(hpet_rtc_interrupt);
1167 #endif /* CONFIG_SPARC32 */
1170 module_init(rtc_init);
1171 module_exit(rtc_exit);
1175 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1176 * (usually during an IDE disk interrupt, with IRQ unmasking off)
1177 * Since the interrupt handler doesn't get called, the IRQ status
1178 * byte doesn't get read, and the RTC stops generating interrupts.
1179 * A timer is set, and will call this function if/when that happens.
1180 * To get it out of this stalled state, we just read the status.
1181 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1182 * (You *really* shouldn't be trying to use a non-realtime system
1183 * for something that requires a steady > 1KHz signal anyways.)
1186 static void rtc_dropped_irq(unsigned long data)
1190 spin_lock_irq(&rtc_lock);
1192 if (hpet_rtc_dropped_irq()) {
1193 spin_unlock_irq(&rtc_lock);
1197 /* Just in case someone disabled the timer from behind our back... */
1198 if (rtc_status & RTC_TIMER_ON)
1199 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
1201 rtc_irq_data += ((rtc_freq/HZ)<<8);
1202 rtc_irq_data &= ~0xff;
1203 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */
1207 spin_unlock_irq(&rtc_lock);
1209 if (printk_ratelimit()) {
1210 printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
1214 /* Now we have new data */
1215 wake_up_interruptible(&rtc_wait);
1217 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
1221 #ifdef CONFIG_PROC_FS
1223 * Info exported via "/proc/driver/rtc".
1226 static int rtc_proc_show(struct seq_file *seq, void *v)
1228 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1229 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1231 unsigned char batt, ctrl;
1234 spin_lock_irq(&rtc_lock);
1235 batt = CMOS_READ(RTC_VALID) & RTC_VRT;
1236 ctrl = CMOS_READ(RTC_CONTROL);
1238 spin_unlock_irq(&rtc_lock);
1241 rtc_get_rtc_time(&tm);
1244 * There is no way to tell if the luser has the RTC set for local
1245 * time or for Universal Standard Time (GMT). Probably local though.
1248 "rtc_time\t: %02d:%02d:%02d\n"
1249 "rtc_date\t: %04d-%02d-%02d\n"
1250 "rtc_epoch\t: %04lu\n",
1251 tm.tm_hour, tm.tm_min, tm.tm_sec,
1252 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
1254 get_rtc_alm_time(&tm);
1257 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1258 * match any value for that particular field. Values that are
1259 * greater than a valid time, but less than 0xc0 shouldn't appear.
1261 seq_puts(seq, "alarm\t\t: ");
1262 if (tm.tm_hour <= 24)
1263 seq_printf(seq, "%02d:", tm.tm_hour);
1265 seq_puts(seq, "**:");
1267 if (tm.tm_min <= 59)
1268 seq_printf(seq, "%02d:", tm.tm_min);
1270 seq_puts(seq, "**:");
1272 if (tm.tm_sec <= 59)
1273 seq_printf(seq, "%02d\n", tm.tm_sec);
1275 seq_puts(seq, "**\n");
1278 "DST_enable\t: %s\n"
1281 "square_wave\t: %s\n"
1283 "update_IRQ\t: %s\n"
1284 "periodic_IRQ\t: %s\n"
1285 "periodic_freq\t: %ld\n"
1286 "batt_status\t: %s\n",
1295 batt ? "okay" : "dead");
1302 static int rtc_proc_open(struct inode *inode, struct file *file)
1304 return single_open(file, rtc_proc_show, NULL);
1308 void rtc_get_rtc_time(struct rtc_time *rtc_tm)
1310 unsigned long uip_watchdog = jiffies, flags;
1312 #ifdef CONFIG_MACH_DECSTATION
1313 unsigned int real_year;
1317 * read RTC once any update in progress is done. The update
1318 * can take just over 2ms. We wait 20ms. There is no need to
1319 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1320 * If you need to know *exactly* when a second has started, enable
1321 * periodic update complete interrupts, (via ioctl) and then
1322 * immediately read /dev/rtc which will block until you get the IRQ.
1323 * Once the read clears, read the RTC time (again via ioctl). Easy.
1326 while (rtc_is_updating() != 0 &&
1327 time_before(jiffies, uip_watchdog + 2*HZ/100))
1331 * Only the values that we read from the RTC are set. We leave
1332 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1333 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1334 * only updated by the RTC when initially set to a non-zero value.
1336 spin_lock_irqsave(&rtc_lock, flags);
1337 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
1338 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
1339 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
1340 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
1341 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
1342 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
1343 /* Only set from 2.6.16 onwards */
1344 rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);
1346 #ifdef CONFIG_MACH_DECSTATION
1347 real_year = CMOS_READ(RTC_DEC_YEAR);
1349 ctrl = CMOS_READ(RTC_CONTROL);
1350 spin_unlock_irqrestore(&rtc_lock, flags);
1352 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1353 BCD_TO_BIN(rtc_tm->tm_sec);
1354 BCD_TO_BIN(rtc_tm->tm_min);
1355 BCD_TO_BIN(rtc_tm->tm_hour);
1356 BCD_TO_BIN(rtc_tm->tm_mday);
1357 BCD_TO_BIN(rtc_tm->tm_mon);
1358 BCD_TO_BIN(rtc_tm->tm_year);
1359 BCD_TO_BIN(rtc_tm->tm_wday);
1362 #ifdef CONFIG_MACH_DECSTATION
1363 rtc_tm->tm_year += real_year - 72;
1367 * Account for differences between how the RTC uses the values
1368 * and how they are defined in a struct rtc_time;
1370 rtc_tm->tm_year += epoch - 1900;
1371 if (rtc_tm->tm_year <= 69)
1372 rtc_tm->tm_year += 100;
1377 static void get_rtc_alm_time(struct rtc_time *alm_tm)
1382 * Only the values that we read from the RTC are set. That
1383 * means only tm_hour, tm_min, and tm_sec.
1385 spin_lock_irq(&rtc_lock);
1386 alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
1387 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
1388 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
1389 ctrl = CMOS_READ(RTC_CONTROL);
1390 spin_unlock_irq(&rtc_lock);
1392 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1393 BCD_TO_BIN(alm_tm->tm_sec);
1394 BCD_TO_BIN(alm_tm->tm_min);
1395 BCD_TO_BIN(alm_tm->tm_hour);
1401 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1402 * Rumour has it that if you frob the interrupt enable/disable
1403 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1404 * ensure you actually start getting interrupts. Probably for
1405 * compatibility with older/broken chipset RTC implementations.
1406 * We also clear out any old irq data after an ioctl() that
1407 * meddles with the interrupt enable/disable bits.
1410 static void mask_rtc_irq_bit_locked(unsigned char bit)
1414 if (hpet_mask_rtc_irq_bit(bit))
1416 val = CMOS_READ(RTC_CONTROL);
1418 CMOS_WRITE(val, RTC_CONTROL);
1419 CMOS_READ(RTC_INTR_FLAGS);
1424 static void set_rtc_irq_bit_locked(unsigned char bit)
1428 if (hpet_set_rtc_irq_bit(bit))
1430 val = CMOS_READ(RTC_CONTROL);
1432 CMOS_WRITE(val, RTC_CONTROL);
1433 CMOS_READ(RTC_INTR_FLAGS);
1439 MODULE_AUTHOR("Paul Gortmaker");
1440 MODULE_LICENSE("GPL");
1441 MODULE_ALIAS_MISCDEV(RTC_MINOR);