patch-1.3.89 linux/drivers/char/rtc.c

• Lines: 743
• Date: Mon Apr 15 10:03:26 1996
• Orig file: v1.3.88/linux/drivers/char/rtc.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.88/linux/drivers/char/rtc.c linux/drivers/char/rtc.c
@@ -0,0 +1,742 @@
+/*
+ *	Real Time Clock interface for Linux	
+ *
+ *	Copyright (C) 1996 Paul Gortmaker
+ *
+ *	This driver allows use of the real time clock (built into
+ *	nearly all computers) from user space. It exports the /dev/rtc
+ *	interface supporting various ioctl() and also the /proc/rtc
+ *	pseudo-file for status information.
+ *
+ *	The ioctls can be used to set the interrupt behaviour and
+ *	generation rate from the RTC via IRQ 8. Then the /dev/rtc
+ *	interface can be used to make use of these timer interrupts,
+ *	be they interval or alarm based.
+ *
+ *	The /dev/rtc interface will block on reads until an interrupt
+ *	has been received. If a RTC interrupt has already happened,
+ *	it will output an unsigned long and then block. The output value
+ *	contains the interrupt status in the low byte and the number of
+ *	interrupts since the last read in the remaining high bytes. The 
+ *	/dev/rtc interface can also be used with the select(2) call.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ *	Based on other minimal char device drivers, like Alan's
+ *	watchdog, Ted's random, etc. etc.
+ *
+ */
+
+#define RTC_VERSION		"1.04"
+
+#define RTC_IRQ 	8	/* Can't see this changing soon.	*/
+#define RTC_IO_BASE	0x70	/* Or this...				*/
+#define RTC_IO_EXTENT	0x10	/* Only really 0x70 to 0x71, but...	*/
+
+/*
+ *	Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
+ *	interrupts disabled. Due to the index-port/data-port (0x70/0x71)
+ *	design of the RTC, we don't want two different things trying to
+ *	get to it at once. (e.g. the periodic 11 min sync from time.c vs.
+ *	this driver.)
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/malloc.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/mc146818rtc.h>
+
+#include <asm/io.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+
+#include <time.h>
+
+/*
+ *	We sponge a minor off of the misc major. No need slurping
+ *	up another valuable major dev number for this.
+ */
+
+#define RTC_MINOR	135
+
+static struct wait_queue *rtc_wait;
+
+static int rtc_lseek(struct inode *inode, struct file *file, off_t offset,
+			int origin);
+
+static int rtc_read(struct inode *inode, struct file *file,
+			char *buf, int count);
+
+static int rtc_ioctl(struct inode *inode, struct file *file,
+			unsigned int cmd, unsigned long arg);
+
+static int rtc_select(struct inode *inode, struct file *file,
+			int sel_type, select_table *wait);
+
+void get_rtc_time (struct tm *rtc_tm);
+void get_rtc_alm_time (struct tm *alm_tm);
+
+inline void set_rtc_irq_bit(unsigned char bit);
+inline void mask_rtc_irq_bit(unsigned char bit);
+
+unsigned char rtc_is_updating(void);
+
+/*
+ *	Bits in rtc_status. (7 bits of room for future expansion)
+ */
+
+#define RTC_IS_OPEN		0x01	/* means /dev/rtc is in use	*/
+
+unsigned char rtc_status = 0;		/* bitmapped status byte.	*/
+unsigned long rtc_irq_data = 0;		/* our output to the world	*/
+
+unsigned char days_in_mo[] = 
+		{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+
+/*
+ *	A very tiny interrupt handler. It runs with SA_INTERRUPT set,
+ *	so that there is no possibility of conflicting with the
+ *	set_rtc_mmss() call that happens during some timer interrupts.
+ *	(See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
+ */
+
+static void rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	/*
+	 *	Can be an alarm interrupt, update complete interrupt,
+	 *	or a periodic interrupt. We store the status in the
+	 *	low byte and the number of interrupts received since
+	 *	the last read in the remainder of rtc_irq_data.
+	 */
+
+	rtc_irq_data += 0x100;
+	rtc_irq_data &= ~0xff;
+	rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
+	wake_up_interruptible(&rtc_wait);	
+}
+
+/*
+ *	Now all the various file operations that we export.
+ */
+
+static int rtc_lseek(struct inode *inode, struct file *file, off_t offset,
+	int origin)
+{
+	return -ESPIPE;
+}
+
+static int rtc_read(struct inode *inode, struct file *file, char *buf, int count)
+{
+	struct wait_queue wait = { current, NULL };
+	int retval;
+	
+	if (count < sizeof(unsigned long))
+		return -EINVAL;
+
+	retval = verify_area(VERIFY_WRITE, buf, sizeof(unsigned long));
+	if (retval)
+		return retval;
+
+	add_wait_queue(&rtc_wait, &wait);
+
+	current->state = TASK_INTERRUPTIBLE;
+		
+	while (rtc_irq_data == 0) {
+		if (file->f_flags & O_NONBLOCK) {
+			retval = -EAGAIN;
+			break;
+		}
+		if (current->signal & ~current->blocked) {
+			retval = -ERESTARTSYS;
+			break;
+		}
+		schedule();
+		continue;
+	}
+
+	if (retval == 0) {
+		memcpy_tofs(buf, &rtc_irq_data, sizeof(unsigned long));
+		rtc_irq_data = 0;
+		retval = sizeof(unsigned long);
+	}
+
+	current->state = TASK_RUNNING;
+	remove_wait_queue(&rtc_wait, &wait);
+
+	return retval;
+}
+
+static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+	unsigned long arg)
+{
+
+	unsigned long flags;
+
+	switch (cmd) {
+		case RTC_AIE_OFF:	/* Mask alarm int. enab. bit	*/
+		{
+			mask_rtc_irq_bit(RTC_AIE);
+			return 0;
+		}
+		case RTC_AIE_ON:	/* Allow alarm interrupts.	*/
+		{
+			set_rtc_irq_bit(RTC_AIE);
+			return 0;
+		}
+		case RTC_PIE_OFF:	/* Mask periodic int. enab. bit	*/
+		{
+			mask_rtc_irq_bit(RTC_PIE);
+			return 0;
+		}
+		case RTC_PIE_ON:	/* Allow periodic ints		*/
+		{
+			unsigned int hz;
+			unsigned char tmp;
+
+			save_flags(flags);
+			cli();
+			tmp = CMOS_READ(RTC_FREQ_SELECT) & 0x0f;
+			restore_flags(flags);
+
+			hz = (tmp ? (65536/(1<<tmp)) : 0);
+
+			/*
+			 * We don't really want Joe User enabling more
+			 * than 64Hz of interrupts on a multi-user machine.
+			 */
+			if ((hz > 64) && (!suser()))
+				return -EPERM;
+
+			set_rtc_irq_bit(RTC_PIE);
+			return 0;
+		}
+		case RTC_UIE_OFF:	/* Mask ints from RTC updates.	*/
+		{
+			mask_rtc_irq_bit(RTC_UIE);
+			return 0;
+		}
+		case RTC_UIE_ON:	/* Allow ints for RTC updates.	*/
+		{
+			set_rtc_irq_bit(RTC_UIE);
+			return 0;
+		}
+		case RTC_ALM_READ:	/* Read the present alarm time */
+		{
+			/*
+			 * This returns a struct tm. Reading >= 0xc0 means
+			 * "don't care" or "match all". Only the tm_hour,
+			 * tm_min, and tm_sec values are filled in.
+			 */
+			int retval;
+			struct tm alm_tm;
+
+			retval = verify_area(VERIFY_WRITE, (struct tm*)arg, sizeof(struct tm));
+			if (retval != 0 )
+				return retval;
+
+			get_rtc_alm_time(&alm_tm);
+
+			memcpy_tofs((struct tm*)arg, &alm_tm, sizeof(struct tm));
+			
+			return 0;
+		}
+		case RTC_ALM_SET:	/* Store a time into the alarm */
+		{
+			/*
+			 * This expects a struct tm. Writing 0xff means
+			 * "don't care" or "match all". Only the tm_hour,
+			 * tm_min and tm_sec are used.
+			 */
+			int retval;
+			unsigned char hrs, min, sec;
+			struct tm alm_tm;
+
+			retval = verify_area(VERIFY_READ, (struct tm*)arg, sizeof(struct tm));
+			if (retval != 0 )
+				return retval;
+
+			memcpy_fromfs(&alm_tm, (struct tm*)arg, sizeof(struct tm));
+
+			hrs = alm_tm.tm_hour;
+			min = alm_tm.tm_min;
+			sec = alm_tm.tm_sec;
+
+			if (hrs >= 24)
+				hrs = 0xff;
+
+			if (min >= 60)
+				min = 0xff;
+
+			if (sec >= 60)
+				sec = 0xff;
+
+			save_flags(flags);
+			cli();
+			if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
+							RTC_ALWAYS_BCD)
+			{
+				BIN_TO_BCD(sec);
+				BIN_TO_BCD(min);
+				BIN_TO_BCD(hrs);
+			}
+			CMOS_WRITE(hrs, RTC_HOURS_ALARM);
+			CMOS_WRITE(min, RTC_MINUTES_ALARM);
+			CMOS_WRITE(sec, RTC_SECONDS_ALARM);
+			restore_flags(flags);
+
+			return 0;
+		}
+		case RTC_RD_TIME:	/* Read the time/date from RTC	*/
+		{
+			int retval;
+			struct tm rtc_tm;
+			
+			retval = verify_area(VERIFY_WRITE, (struct tm*)arg, sizeof(struct tm));
+			if (retval !=0 )
+				return retval;
+
+			get_rtc_time(&rtc_tm);
+			memcpy_tofs((struct tm*)arg, &rtc_tm, sizeof(struct tm));
+			return 0;
+		}
+		case RTC_SET_TIME:	/* Set the RTC */
+		{
+			int retval;
+			struct tm rtc_tm;
+			unsigned char mon, day, hrs, min, sec, leap_yr;
+			unsigned char save_control, save_freq_select;
+			unsigned int yrs;
+			unsigned long flags;
+			
+			if (!suser())
+				return -EPERM;
+
+			retval = verify_area(VERIFY_READ, (struct tm*)arg, sizeof(struct tm));
+			if (retval !=0 )
+				return retval;
+
+			memcpy_fromfs(&rtc_tm, (struct tm*)arg, sizeof(struct tm));
+
+			yrs = rtc_tm.tm_year + 1900;
+			mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
+			day = rtc_tm.tm_mday;
+			hrs = rtc_tm.tm_hour;
+			min = rtc_tm.tm_min;
+			sec = rtc_tm.tm_sec;
+
+			if ((yrs < 1970) || (yrs > 2069))
+				return -EINVAL;
+
+			leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
+
+			if ((mon > 12) || (day == 0))
+				return -EINVAL;
+
+			if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
+				return -EINVAL;
+			
+			if ((hrs >= 24) || (min >= 60) || (sec >= 60))
+				return -EINVAL;
+
+			if (yrs >= 2000)
+				yrs -= 2000;	/* RTC (0, 1, ... 69) */
+			else
+				yrs -= 1900;	/* RTC (70, 71, ... 99) */
+
+			save_flags(flags);
+			cli();
+			if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
+							RTC_ALWAYS_BCD)
+			{
+				BIN_TO_BCD(sec);
+				BIN_TO_BCD(min);
+				BIN_TO_BCD(hrs);
+				BIN_TO_BCD(day);
+				BIN_TO_BCD(mon);
+				BIN_TO_BCD(yrs);
+			}
+
+			save_control = CMOS_READ(RTC_CONTROL);
+			CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
+			save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
+			CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+			CMOS_WRITE(yrs, RTC_YEAR);
+			CMOS_WRITE(mon, RTC_MONTH);
+			CMOS_WRITE(day, RTC_DAY_OF_MONTH);
+			CMOS_WRITE(hrs, RTC_HOURS);
+			CMOS_WRITE(min, RTC_MINUTES);
+			CMOS_WRITE(sec, RTC_SECONDS);
+
+			CMOS_WRITE(save_control, RTC_CONTROL);
+			CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
+
+			restore_flags(flags);
+			return 0;
+		}
+		case RTC_IRQP_READ:	/* Read the periodic IRQ rate.	*/
+		{
+			unsigned long hz;
+			int retval;
+
+			retval = verify_area(VERIFY_WRITE, (unsigned long*)arg, sizeof(unsigned long));
+			if (retval != 0)
+				return retval;
+
+			save_flags(flags);
+			cli();
+			retval = CMOS_READ(RTC_FREQ_SELECT) & 0x0f;
+			restore_flags(flags);
+			hz = (retval ? (65536/(1<<retval)) : 0);
+			memcpy_tofs((unsigned long*)arg, &hz, sizeof(unsigned long));
+			return 0;
+		}
+		case RTC_IRQP_SET:	/* Set periodic IRQ rate.	*/
+		{
+			int tmp = 0;
+			unsigned char val;
+
+			/* 
+			 * The max we can do is 8192Hz.
+			 */
+			if (arg > 8192)
+				return -EINVAL;
+			/*
+			 * We don't really want Joe User generating more
+			 * than 64Hz of interrupts on a multi-user machine.
+			 */
+			if ((arg > 64) && (!suser()))
+				return -EPERM;
+
+			while (arg > (1<<tmp))
+				tmp++;
+
+			/*
+			 * Check that the input was really a power of 2.
+			 */
+			if ((arg != 0) && (arg != (1<<tmp)))
+				return -EINVAL;
+
+			save_flags(flags);
+			cli();
+			val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
+
+			if (arg == 0) {
+				CMOS_WRITE(val, RTC_FREQ_SELECT);
+				restore_flags(flags);
+				return 0;
+			}
+
+			val |= (16 - tmp);
+			CMOS_WRITE(val, RTC_FREQ_SELECT);
+			restore_flags(flags);
+			return 0;
+		}
+		default:
+			return -EINVAL;
+	}
+}
+
+/*
+ *	We enforce only one user at a time here with the open/close.
+ *	Also clear the previous interrupt data on an open, and clean
+ *	up things on a close.
+ */
+
+static int rtc_open(struct inode *inode, struct file *file)
+{
+
+	if(rtc_status & RTC_IS_OPEN)
+		return -EBUSY;
+
+	rtc_status |= RTC_IS_OPEN;
+	rtc_irq_data = 0;
+	return 0;
+}
+
+static void rtc_release(struct inode *inode, struct file *file)
+{
+
+	/*
+	 * Turn off all interrupts once the device is no longer
+	 * in use, and clear the data.
+	 */
+
+	unsigned char tmp;
+	unsigned long flags;
+
+	save_flags(flags);
+	cli();
+	tmp = CMOS_READ(RTC_CONTROL);
+	tmp &=  ~RTC_PIE;
+	tmp &=  ~RTC_AIE;
+	tmp &=  ~RTC_UIE;
+	CMOS_WRITE(tmp, RTC_CONTROL);
+	CMOS_READ(RTC_INTR_FLAGS);
+	restore_flags(flags);
+	rtc_irq_data = 0;
+	rtc_status &= ~RTC_IS_OPEN;
+}
+
+static int rtc_select(struct inode *inode, struct file *file,
+			int sel_type, select_table *wait)
+{
+	if (sel_type == SEL_IN) {
+		if (rtc_irq_data != 0)
+			return 1;
+		select_wait(&rtc_wait, wait);
+	}
+	return 0;
+}
+
+/*
+ *	The various file operations we support.
+ */
+
+static struct file_operations rtc_fops = {
+	rtc_lseek,
+	rtc_read,
+	NULL,		/* No write */
+	NULL,		/* No readdir */
+	rtc_select,
+	rtc_ioctl,
+	NULL,		/* No mmap */
+	rtc_open,
+	rtc_release
+};
+
+static struct miscdevice rtc_dev=
+{
+	RTC_MINOR,
+	"rtc",
+	&rtc_fops
+};
+
+int rtc_init(void)
+{
+	printk("Real Time Clock Driver v%s\n", RTC_VERSION);
+	if(request_irq(RTC_IRQ, rtc_interrupt, SA_INTERRUPT, "rtc", NULL))
+	{
+		/* Yeah right, seeing as irq 8 doesn't even hit the bus. */
+		printk("rtc: IRQ %d is not free.\n", RTC_IRQ);
+		return -EIO;
+	}
+	misc_register(&rtc_dev);
+	/* Check region? Naaah! Just snarf it up. */
+	request_region(RTC_IO_BASE, RTC_IO_EXTENT, "rtc");
+	rtc_wait = NULL;
+	return 0;
+}
+
+/*
+ *	Info exported via "/proc/rtc".
+ */
+
+int get_rtc_status(char *buf)
+{
+	char *p;
+	struct tm tm;
+	unsigned char freq, batt, ctrl;
+	unsigned long flags;
+
+	save_flags(flags);
+	freq = CMOS_READ(RTC_FREQ_SELECT) & 0x0F;
+	batt = CMOS_READ(RTC_VALID) & RTC_VRT;
+	ctrl = CMOS_READ(RTC_CONTROL);
+	restore_flags(flags);
+
+	p = buf;
+	p += sprintf(p, "Real Time Clock Status:\n");
+
+	get_rtc_time(&tm);
+
+	/*
+	 * There is no way to tell if the luser has the RTC set for local
+	 * time or for Universal Standard Time (GMT). Probably local though.
+	 */
+	p += sprintf(p, "\tRTC reports %02d:%02d:%02d of %d-%d-%d.\n",
+		tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_mday, 
+		tm.tm_mon + 1, tm.tm_year + 1900);
+
+	get_rtc_alm_time(&tm);
+
+	/*
+	 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
+	 * match any value for that particular field. Values that are
+	 * greater than a valid time, but less than 0xc0 shouldn't appear.
+	 */
+	p += sprintf(p, "\tAlarm set to match: ");
+	if (tm.tm_hour <= 24)
+		p += sprintf(p, "hour=%d, ", tm.tm_hour);
+	else
+		p += sprintf(p, "hour=any, ");
+	if (tm.tm_min <= 59)
+		p += sprintf(p, "min=%d, ", tm.tm_min);
+	else
+		p += sprintf(p, "min=any, ");
+	if (tm.tm_sec <= 59)
+		p += sprintf(p, "sec=%d.\n", tm.tm_sec);
+	else
+		p += sprintf(p, "sec=any.\n");
+
+	p += sprintf(p, "\tMisc. settings: daylight=%s; BCD=%s; 24hr=%s; Sq-Wave=%s.\n",
+		((ctrl & RTC_DST_EN) ? "yes" : "no" ),
+		((ctrl & RTC_DM_BINARY) ? "no" : "yes" ),
+		((ctrl & RTC_24H) ? "yes" : "no" ),
+		((ctrl & RTC_SQWE) ? "yes" : "no" ));
+
+	p += sprintf(p, "\tInterrupt for: alarm=%s; update=%s; periodic=%s.\n",
+		((ctrl & RTC_AIE) ? "yes" : "no" ),
+		((ctrl & RTC_UIE) ? "yes" : "no" ),
+		((ctrl & RTC_PIE) ? "yes" : "no" ));
+
+	p += sprintf(p, "\tPeriodic interrupt rate set to %dHz.\n",
+		(freq ? (65536/(1<<freq)) : 0));
+
+	p += sprintf(p, "\tRTC reports that CMOS battery is %s.\n",
+		(batt ? "okay" : "dead"));
+
+	return  p - buf;
+}
+
+/*
+ * Returns true if a clock update is in progress
+ */
+inline unsigned char rtc_is_updating(void)
+{
+	unsigned long flags;
+	unsigned char uip;
+
+	save_flags(flags);
+	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
+	restore_flags(flags);
+	return uip;
+}
+
+void get_rtc_time(struct tm *rtc_tm)
+{
+
+	unsigned long flags, uip_watchdog = jiffies;
+	unsigned char ctrl;
+
+	/*
+	 * read RTC once any update in progress is done. The update
+	 * can take just over 2ms. We wait 10 to 20ms. There is no need to
+	 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
+	 * If you need to know *exactly* when a second has started, enable
+	 * periodic update complete interrupts, (via ioctl) and then 
+	 * immediately read /dev/rtc which will block until you get the IRQ.
+	 * Once the read clears, read the RTC time (again via ioctl). Easy.
+	 */
+
+	if (rtc_is_updating() != 0)
+		while (jiffies - uip_watchdog < 2*HZ/100)
+			barrier();
+
+	/*
+	 * Only the values that we read from the RTC are set. We leave
+	 * tm_wday, tm_yday and tm_isdst untouched. Even though the
+	 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
+	 * by the RTC when initially set to a non-zero value.
+	 */
+	save_flags(flags);
+	cli();
+	rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
+	rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
+	rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
+	rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
+	rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
+	rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
+	ctrl = CMOS_READ(RTC_CONTROL);
+	restore_flags(flags);
+
+	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+	{
+		BCD_TO_BIN(rtc_tm->tm_sec);
+		BCD_TO_BIN(rtc_tm->tm_min);
+		BCD_TO_BIN(rtc_tm->tm_hour);
+		BCD_TO_BIN(rtc_tm->tm_mday);
+		BCD_TO_BIN(rtc_tm->tm_mon);
+		BCD_TO_BIN(rtc_tm->tm_year);
+	}
+
+	/*
+	 * Account for differences between how the RTC uses the values
+	 * and how they are defined in a struct tm;
+	 */
+	if (rtc_tm->tm_year <= 69)
+		rtc_tm->tm_year += 100;
+
+	rtc_tm->tm_mon--;
+}
+
+void get_rtc_alm_time(struct tm *alm_tm)
+{
+	unsigned long flags;
+	unsigned char ctrl;
+
+	/*
+	 * Only the values that we read from the RTC are set. That
+	 * means only tm_hour, tm_min, and tm_sec.
+	 */
+	save_flags(flags);
+	cli();
+	alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
+	alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
+	alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
+	ctrl = CMOS_READ(RTC_CONTROL);
+	restore_flags(flags);
+
+	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+	{
+		BCD_TO_BIN(alm_tm->tm_sec);
+		BCD_TO_BIN(alm_tm->tm_min);
+		BCD_TO_BIN(alm_tm->tm_hour);
+	}
+}
+
+/*
+ * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
+ * Rumour has it that if you frob the interrupt enable/disable
+ * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
+ * ensure you actually start getting interrupts. Probably for
+ * compatibility with older/broken chipset RTC implementations.
+ * We also clear out any old irq data after an ioctl() that
+ * meddles the interrupt enable/disable bits.
+ */
+inline void mask_rtc_irq_bit(unsigned char bit)
+{
+	unsigned char val;
+	unsigned long flags;
+
+	save_flags(flags);
+	cli();
+	val = CMOS_READ(RTC_CONTROL);
+	val &=  ~bit;
+	CMOS_WRITE(val, RTC_CONTROL);
+	CMOS_READ(RTC_INTR_FLAGS);
+	restore_flags(flags);
+	rtc_irq_data = 0;
+}
+
+inline void set_rtc_irq_bit(unsigned char bit)
+{
+	unsigned char val;
+	unsigned long flags;
+
+	save_flags(flags);
+	cli();
+	val = CMOS_READ(RTC_CONTROL);
+	val |= bit;
+	CMOS_WRITE(val, RTC_CONTROL);
+	CMOS_READ(RTC_INTR_FLAGS);
+	restore_flags(flags);
+	rtc_irq_data = 0;
+}
+