patch-2.2.11 linux/drivers/sgi/char/ds1286.c

• Lines: 571
• Date: Mon Aug 9 12:04:40 1999
• Orig file: v2.2.10/linux/drivers/sgi/char/ds1286.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.2.10/linux/drivers/sgi/char/ds1286.c linux/drivers/sgi/char/ds1286.c
@@ -0,0 +1,570 @@
+/* $Id: ds1286.c,v 1.3.2.3 1999/06/17 12:08:44 ralf Exp $
+ *
+ *	Real Time Clock interface for Linux	
+ *
+ *	Copyright (C) 1998, 1999 Ralf Baechle
+ *	
+ *	Based on code written by 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.
+ */
+#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/init.h>
+#include <linux/poll.h>
+#include <linux/rtc.h>
+
+#include <asm/ds1286.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/spinlock.h>
+#include <asm/system.h>
+
+#define DS1286_VERSION		"1.0"
+
+/*
+ *	We sponge a minor off of the misc major. No need slurping
+ *	up another valuable major dev number for this. If you add
+ *	an ioctl, make sure you don't conflict with SPARC's RTC
+ *	ioctls.
+ */
+
+static struct wait_queue *ds1286_wait;
+
+static long long ds1286_llseek(struct file *file, loff_t offset, int origin);
+
+static ssize_t ds1286_read(struct file *file, char *buf,
+			size_t count, loff_t *ppos);
+
+static int ds1286_ioctl(struct inode *inode, struct file *file,
+                        unsigned int cmd, unsigned long arg);
+
+static unsigned int ds1286_poll(struct file *file, poll_table *wait);
+
+void get_rtc_time (struct rtc_time *rtc_tm);
+void get_rtc_alm_time (struct rtc_time *alm_tm);
+
+void set_rtc_irq_bit(unsigned char bit);
+void clear_rtc_irq_bit(unsigned char bit);
+
+static inline unsigned char ds1286_is_updating(void);
+
+#ifdef __SMP__
+static spinlock_t ds1286_lock = SPIN_LOCK_UNLOCKED;
+#endif
+
+/*
+ *	Bits in rtc_status. (7 bits of room for future expansion)
+ */
+
+#define RTC_IS_OPEN		0x01	/* means /dev/rtc is in use	*/
+#define RTC_TIMER_ON		0x02	/* missed irq timer active	*/
+
+unsigned char ds1286_status = 0;	/* bitmapped status byte.	*/
+unsigned long ds1286_freq = 0;		/* Current periodic IRQ rate	*/
+unsigned long ds1286_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.)
+ */
+
+/*
+ *	Now all the various file operations that we export.
+ */
+
+static long long ds1286_llseek(struct file *file, loff_t offset, int origin)
+{
+	return -ESPIPE;
+}
+
+static ssize_t ds1286_read(struct file *file, char *buf,
+                           size_t count, loff_t *ppos)
+{
+	struct wait_queue wait = { current, NULL };
+	unsigned long data;
+	ssize_t retval;
+	
+	if (count < sizeof(unsigned long))
+		return -EINVAL;
+
+	add_wait_queue(&ds1286_wait, &wait);
+
+	current->state = TASK_INTERRUPTIBLE;
+		
+	while ((data = xchg(&ds1286_irq_data, 0)) == 0) {
+		if (file->f_flags & O_NONBLOCK) {
+			retval = -EAGAIN;
+			goto out;
+		}
+		if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+			goto out;
+		}
+		schedule();
+	}
+
+	retval = put_user(data, (unsigned long *)buf); 
+	if (!retval)
+		retval = sizeof(unsigned long); 
+ out:
+	current->state = TASK_RUNNING;
+	remove_wait_queue(&ds1286_wait, &wait);
+
+	return retval;
+}
+
+static int ds1286_ioctl(struct inode *inode, struct file *file,
+                        unsigned int cmd, unsigned long arg)
+{
+
+	struct rtc_time wtime; 
+
+	switch (cmd) {
+	case RTC_AIE_OFF:	/* Mask alarm int. enab. bit	*/
+	{
+		unsigned int flags;
+		unsigned char val;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		spin_lock_irqsave(&ds1286_lock, flags);
+		val = CMOS_READ(RTC_CMD);
+		val |=  RTC_TDM;
+		CMOS_WRITE(val, RTC_CMD);
+		spin_unlock_irqrestore(&ds1286_lock, flags);
+
+		return 0;
+	}
+	case RTC_AIE_ON:	/* Allow alarm interrupts.	*/
+	{
+		unsigned int flags;
+		unsigned char val;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		spin_lock_irqsave(&ds1286_lock, flags);
+		val = CMOS_READ(RTC_CMD);
+		val &=  ~RTC_TDM;
+		CMOS_WRITE(val, RTC_CMD);
+		spin_unlock_irqrestore(&ds1286_lock, flags);
+
+		return 0;
+	}
+	case RTC_WIE_OFF:	/* Mask watchdog int. enab. bit	*/
+	{
+		unsigned int flags;
+		unsigned char val;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		spin_lock_irqsave(&ds1286_lock, flags);
+		val = CMOS_READ(RTC_CMD);
+		val |= RTC_WAM;
+		CMOS_WRITE(val, RTC_CMD);
+		spin_unlock_irqrestore(&ds1286_lock, flags);
+
+		return 0;
+	}
+	case RTC_WIE_ON:	/* Allow watchdog interrupts.	*/
+	{
+		unsigned int flags;
+		unsigned char val;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		spin_lock_irqsave(&ds1286_lock, flags);
+		val = CMOS_READ(RTC_CMD);
+		val &= ~RTC_WAM;
+		CMOS_WRITE(val, RTC_CMD);
+		spin_unlock_irqrestore(&ds1286_lock, flags);
+
+		return 0;
+	}
+	case RTC_ALM_READ:	/* Read the present alarm time */
+	{
+		/*
+		 * This returns a struct rtc_time. Reading >= 0xc0
+		 * means "don't care" or "match all". Only the tm_hour,
+		 * tm_min, and tm_sec values are filled in.
+		 */
+
+		get_rtc_alm_time(&wtime);
+		break; 
+	}
+	case RTC_ALM_SET:	/* Store a time into the alarm */
+	{
+		/*
+		 * This expects a struct rtc_time. Writing 0xff means
+		 * "don't care" or "match all". Only the tm_hour,
+		 * tm_min and tm_sec are used.
+		 */
+		unsigned char hrs, min, sec;
+		struct rtc_time alm_tm;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
+				   sizeof(struct rtc_time)))
+			return -EFAULT;
+
+		hrs = alm_tm.tm_hour;
+		min = alm_tm.tm_min;
+
+		if (hrs >= 24)
+			hrs = 0xff;
+
+		if (min >= 60)
+			min = 0xff;
+
+		BIN_TO_BCD(sec);
+		BIN_TO_BCD(min);
+		BIN_TO_BCD(hrs);
+
+		spin_lock(&ds1286_lock);
+		CMOS_WRITE(hrs, RTC_HOURS_ALARM);
+		CMOS_WRITE(min, RTC_MINUTES_ALARM);
+		spin_unlock(&ds1286_lock);
+
+		return 0;
+	}
+	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
+	{
+		get_rtc_time(&wtime);
+		break;
+	}
+	case RTC_SET_TIME:	/* Set the RTC */
+	{
+		struct rtc_time rtc_tm;
+		unsigned char mon, day, hrs, min, sec, leap_yr;
+		unsigned char save_control;
+		unsigned int yrs, flags;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
+				   sizeof(struct rtc_time)))
+			return -EFAULT;
+
+		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)
+			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 -= 1940) > 255)    /* They are unsigned */
+			return -EINVAL;
+
+		if (yrs >= 100)
+			yrs -= 100;
+
+		BIN_TO_BCD(sec);
+		BIN_TO_BCD(min);
+		BIN_TO_BCD(hrs);
+		BIN_TO_BCD(day);
+		BIN_TO_BCD(mon);
+		BIN_TO_BCD(yrs);
+
+		spin_lock_irqsave(&ds1286_lock, flags);
+		save_control = CMOS_READ(RTC_CMD);
+		CMOS_WRITE((save_control|RTC_TE), RTC_CMD);
+
+		CMOS_WRITE(yrs, RTC_YEAR);
+		CMOS_WRITE(mon, RTC_MONTH);
+		CMOS_WRITE(day, RTC_DATE);
+		CMOS_WRITE(hrs, RTC_HOURS);
+		CMOS_WRITE(min, RTC_MINUTES);
+		CMOS_WRITE(sec, RTC_SECONDS);
+		CMOS_WRITE(0, RTC_HUNDREDTH_SECOND);
+
+		CMOS_WRITE(save_control, RTC_CMD);
+		spin_unlock_irqrestore(&ds1286_lock, flags);
+
+		return 0;
+	}
+	default:
+		return -EINVAL;
+	}
+	return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
+}
+
+/*
+ *	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 ds1286_open(struct inode *inode, struct file *file)
+{
+	if(ds1286_status & RTC_IS_OPEN)
+		return -EBUSY;
+
+	ds1286_status |= RTC_IS_OPEN;
+	ds1286_irq_data = 0;
+	return 0;
+}
+
+static int ds1286_release(struct inode *inode, struct file *file)
+{
+	ds1286_status &= ~RTC_IS_OPEN;
+	return 0;
+}
+
+static unsigned int ds1286_poll(struct file *file, poll_table *wait)
+{
+	poll_wait(file, &ds1286_wait, wait);
+	if (ds1286_irq_data != 0)
+		return POLLIN | POLLRDNORM;
+	return 0;
+}
+
+/*
+ *	The various file operations we support.
+ */
+
+static struct file_operations ds1286_fops = {
+	ds1286_llseek,
+	ds1286_read,
+	NULL,		/* No write */
+	NULL,		/* No readdir */
+	ds1286_poll,
+	ds1286_ioctl,
+	NULL,		/* No mmap */
+	ds1286_open,
+	NULL,		/* No flush */
+	ds1286_release
+};
+
+static struct miscdevice ds1286_dev=
+{
+	RTC_MINOR,
+	"rtc",
+	&ds1286_fops
+};
+
+__initfunc(int ds1286_init(void))
+{
+	printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION);
+	misc_register(&ds1286_dev);
+
+	ds1286_wait = NULL;
+
+	return 0;
+}
+
+static char *days[] = {
+	"***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+};
+
+/*
+ *	Info exported via "/proc/rtc".
+ */
+int get_ds1286_status(char *buf)
+{
+	char *p, *s;
+	struct rtc_time tm;
+	unsigned char hundredth, month, cmd, amode;
+
+	p = buf;
+
+	get_rtc_time(&tm);
+	hundredth = CMOS_READ(RTC_HUNDREDTH_SECOND);
+	hundredth = BCD_TO_BIN(hundredth);
+
+	p += sprintf(p,
+	             "rtc_time\t: %02d:%02d:%02d.%02d\n"
+	             "rtc_date\t: %04d-%02d-%02d\n",
+		     tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth,
+		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
+
+	/*
+	 * 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.
+	 */
+	get_rtc_alm_time(&tm);
+	p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]);
+	if (tm.tm_hour <= 24)
+		p += sprintf(p, "%02d:", tm.tm_hour);
+	else
+		p += sprintf(p, "**:");
+
+	if (tm.tm_min <= 59)
+		p += sprintf(p, "%02d\n", tm.tm_min);
+	else
+		p += sprintf(p, "**\n");
+
+	month = CMOS_READ(RTC_MONTH);
+	p += sprintf(p,
+	             "oscillator\t: %s\n"
+	             "square_wave\t: %s\n",
+	             (month & RTC_EOSC) ? "disabled" : "enabled",
+	             (month & RTC_ESQW) ? "disabled" : "enabled");
+
+	amode = ((CMOS_READ(RTC_MINUTES_ALARM) & 0x80) >> 5) |
+	        ((CMOS_READ(RTC_HOURS_ALARM) & 0x80) >> 6) |
+	        ((CMOS_READ(RTC_DAY_ALARM) & 0x80) >> 7);
+	if (amode == 7)      s = "each minute";
+	else if (amode == 3) s = "minutes match";
+	else if (amode == 1) s = "hours and minutes match";
+	else if (amode == 0) s = "days, hours and minutes match";
+	else                 s = "invalid";
+	p += sprintf(p, "alarm_mode\t: %s\n", s);
+
+	cmd = CMOS_READ(RTC_CMD);
+	p += sprintf(p,
+	             "alarm_enable\t: %s\n"
+	             "wdog_alarm\t: %s\n"
+	             "alarm_mask\t: %s\n"
+	             "wdog_alarm_mask\t: %s\n"
+	             "interrupt_mode\t: %s\n"
+	             "INTB_mode\t: %s_active\n"
+	             "interrupt_pins\t: %s\n",
+		     (cmd & RTC_TDF) ? "yes" : "no",
+		     (cmd & RTC_WAF) ? "yes" : "no",
+		     (cmd & RTC_TDM) ? "disabled" : "enabled",
+		     (cmd & RTC_WAM) ? "disabled" : "enabled",
+		     (cmd & RTC_PU_LVL) ? "pulse" : "level",
+		     (cmd & RTC_IBH_LO) ? "low" : "high",
+	             (cmd & RTC_IPSW) ? "unswapped" : "swapped");
+
+	return  p - buf;
+}
+
+/*
+ * Returns true if a clock update is in progress
+ */
+static inline unsigned char ds1286_is_updating(void)
+{
+	return CMOS_READ(RTC_CMD) & RTC_TE;
+}
+
+void get_rtc_time(struct rtc_time *rtc_tm)
+{
+	unsigned long uip_watchdog = jiffies;
+	unsigned char save_control;
+	unsigned int flags;
+
+	/*
+	 * 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 (ds1286_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.
+	 */
+	spin_lock_irqsave(&ds1286_lock, flags);
+	save_control = CMOS_READ(RTC_CMD);
+	CMOS_WRITE((save_control|RTC_TE), RTC_CMD);
+
+	rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
+	rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
+	rtc_tm->tm_hour = CMOS_READ(RTC_HOURS) & 0x1f;
+	rtc_tm->tm_mday = CMOS_READ(RTC_DATE);
+	rtc_tm->tm_mon = CMOS_READ(RTC_MONTH) & 0x1f;
+	rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
+
+	CMOS_WRITE(save_control, RTC_CMD);
+	spin_unlock_irqrestore(&ds1286_lock, flags);
+
+	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 rtc_time;
+	 */
+	if (rtc_tm->tm_year < 45)
+		rtc_tm->tm_year += 30;
+	if ((rtc_tm->tm_year += 40) < 70)
+		rtc_tm->tm_year += 100;
+
+	rtc_tm->tm_mon--;
+}
+
+void get_rtc_alm_time(struct rtc_time *alm_tm)
+{
+	unsigned char cmd;
+	unsigned int flags;
+
+	/*
+	 * Only the values that we read from the RTC are set. That
+	 * means only tm_wday, tm_hour, tm_min.
+	 */
+	spin_lock_irqsave(&ds1286_lock, flags);
+	alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM) & 0x7f;
+	alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM)  & 0x1f;
+	alm_tm->tm_wday = CMOS_READ(RTC_DAY_ALARM)    & 0x07;
+	cmd = CMOS_READ(RTC_CMD);
+	spin_unlock_irqrestore(&ds1286_lock, flags);
+
+	BCD_TO_BIN(alm_tm->tm_min);
+	BCD_TO_BIN(alm_tm->tm_hour);
+	alm_tm->tm_sec = 0;
+}