rtc.c

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	return r;
}

static void rtc_release_region(void)
{
	if (RTC_IOMAPPED)
		release_region(RTC_PORT(0), rtc_size);
	else
		release_mem_region(RTC_PORT(0), rtc_size);
}

static int __init rtc_init(void)
{
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry *ent;
#endif
#if defined(__alpha__) || defined(__mips__)
	unsigned int year, ctrl;
	char *guess = NULL;
#endif
#ifdef CONFIG_SPARC32
	struct linux_ebus *ebus;
	struct linux_ebus_device *edev;
#else
	void *r;
#ifdef RTC_IRQ
	irq_handler_t rtc_int_handler_ptr;
#endif
#endif

#ifdef CONFIG_SPARC32
	for_each_ebus(ebus) {
		for_each_ebusdev(edev, ebus) {
			if(strcmp(edev->prom_node->name, "rtc") == 0) {
				rtc_port = edev->resource[0].start;
				rtc_irq = edev->irqs[0];
				goto found;
			}
		}
	}
	rtc_has_irq = 0;
	printk(KERN_ERR "rtc_init: no PC rtc found\n");
	return -EIO;

found:
	if (rtc_irq == PCI_IRQ_NONE) {
		rtc_has_irq = 0;
		goto no_irq;
	}

	/*
	 * XXX Interrupt pin #7 in Espresso is shared between RTC and
	 * PCI Slot 2 INTA# (and some INTx# in Slot 1).
	 */
	if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc", (void *)&rtc_port)) {
		rtc_has_irq = 0;
		printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
		return -EIO;
	}
no_irq:
#else
	r = rtc_request_region(RTC_IO_EXTENT);

	/*
	 * If we've already requested a smaller range (for example, because
	 * PNPBIOS or ACPI told us how the device is configured), the request
	 * above might fail because it's too big.
	 *
	 * If so, request just the range we actually use.
	 */
	if (!r)
		r = rtc_request_region(RTC_IO_EXTENT_USED);
	if (!r) {
#ifdef RTC_IRQ
		rtc_has_irq = 0;
#endif
		printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
		       (long)(RTC_PORT(0)));
		return -EIO;
	}

#ifdef RTC_IRQ
	if (is_hpet_enabled()) {
		rtc_int_handler_ptr = hpet_rtc_interrupt;
	} else {
		rtc_int_handler_ptr = rtc_interrupt;
	}

	if(request_irq(RTC_IRQ, rtc_int_handler_ptr, IRQF_DISABLED, "rtc", NULL)) {
		/* Yeah right, seeing as irq 8 doesn't even hit the bus. */
		rtc_has_irq = 0;
		printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
		rtc_release_region();
		return -EIO;
	}
	hpet_rtc_timer_init();

#endif

#endif /* CONFIG_SPARC32 vs. others */

	if (misc_register(&rtc_dev)) {
#ifdef RTC_IRQ
		free_irq(RTC_IRQ, NULL);
		rtc_has_irq = 0;
#endif
		rtc_release_region();
		return -ENODEV;
	}

#ifdef CONFIG_PROC_FS
	ent = create_proc_entry("driver/rtc", 0, NULL);
	if (ent)
		ent->proc_fops = &rtc_proc_fops;
	else
		printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
#endif

#if defined(__alpha__) || defined(__mips__)
	rtc_freq = HZ;
	
	/* Each operating system on an Alpha uses its own epoch.
	   Let's try to guess which one we are using now. */
	
	if (rtc_is_updating() != 0)
		msleep(20);
	
	spin_lock_irq(&rtc_lock);
	year = CMOS_READ(RTC_YEAR);
	ctrl = CMOS_READ(RTC_CONTROL);
	spin_unlock_irq(&rtc_lock);
	
	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
		BCD_TO_BIN(year);       /* This should never happen... */
	
	if (year < 20) {
		epoch = 2000;
		guess = "SRM (post-2000)";
	} else if (year >= 20 && year < 48) {
		epoch = 1980;
		guess = "ARC console";
	} else if (year >= 48 && year < 72) {
		epoch = 1952;
		guess = "Digital UNIX";
#if defined(__mips__)
	} else if (year >= 72 && year < 74) {
		epoch = 2000;
		guess = "Digital DECstation";
#else
	} else if (year >= 70) {
		epoch = 1900;
		guess = "Standard PC (1900)";
#endif
	}
	if (guess)
		printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", guess, epoch);
#endif
#ifdef RTC_IRQ
	if (rtc_has_irq == 0)
		goto no_irq2;

	spin_lock_irq(&rtc_lock);
	rtc_freq = 1024;
	if (!hpet_set_periodic_freq(rtc_freq)) {
		/* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
		CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), RTC_FREQ_SELECT);
	}
	spin_unlock_irq(&rtc_lock);
no_irq2:
#endif

	(void) init_sysctl();

	printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");

	return 0;
}

static void __exit rtc_exit (void)
{
	cleanup_sysctl();
	remove_proc_entry ("driver/rtc", NULL);
	misc_deregister(&rtc_dev);

#ifdef CONFIG_SPARC32
	if (rtc_has_irq)
		free_irq (rtc_irq, &rtc_port);
#else
	rtc_release_region();
#ifdef RTC_IRQ
	if (rtc_has_irq)
		free_irq (RTC_IRQ, NULL);
#endif
#endif /* CONFIG_SPARC32 */
}

module_init(rtc_init);
module_exit(rtc_exit);

#ifdef RTC_IRQ
/*
 * 	At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
 *	(usually during an IDE disk interrupt, with IRQ unmasking off)
 *	Since the interrupt handler doesn't get called, the IRQ status
 *	byte doesn't get read, and the RTC stops generating interrupts.
 *	A timer is set, and will call this function if/when that happens.
 *	To get it out of this stalled state, we just read the status.
 *	At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
 *	(You *really* shouldn't be trying to use a non-realtime system 
 *	for something that requires a steady > 1KHz signal anyways.)
 */

static void rtc_dropped_irq(unsigned long data)
{
	unsigned long freq;

	spin_lock_irq (&rtc_lock);

	if (hpet_rtc_dropped_irq()) {
		spin_unlock_irq(&rtc_lock);
		return;
	}

	/* Just in case someone disabled the timer from behind our back... */
	if (rtc_status & RTC_TIMER_ON)
		mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);

	rtc_irq_data += ((rtc_freq/HZ)<<8);
	rtc_irq_data &= ~0xff;
	rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);	/* restart */

	freq = rtc_freq;

	spin_unlock_irq(&rtc_lock);

	if (printk_ratelimit())
		printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", freq);

	/* Now we have new data */
	wake_up_interruptible(&rtc_wait);

	kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
}
#endif

#ifdef CONFIG_PROC_FS
/*
 *	Info exported via "/proc/driver/rtc".
 */

static int rtc_proc_show(struct seq_file *seq, void *v)
{
#define YN(bit) ((ctrl & bit) ? "yes" : "no")
#define NY(bit) ((ctrl & bit) ? "no" : "yes")
	struct rtc_time tm;
	unsigned char batt, ctrl;
	unsigned long freq;

	spin_lock_irq(&rtc_lock);
	batt = CMOS_READ(RTC_VALID) & RTC_VRT;
	ctrl = CMOS_READ(RTC_CONTROL);
	freq = rtc_freq;
	spin_unlock_irq(&rtc_lock);


	rtc_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.
	 */
	seq_printf(seq,
		   "rtc_time\t: %02d:%02d:%02d\n"
		   "rtc_date\t: %04d-%02d-%02d\n"
		   "rtc_epoch\t: %04lu\n",
		   tm.tm_hour, tm.tm_min, tm.tm_sec,
		   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);

	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.
	 */
	seq_puts(seq, "alarm\t\t: ");
	if (tm.tm_hour <= 24)
		seq_printf(seq, "%02d:", tm.tm_hour);
	else
		seq_puts(seq, "**:");

	if (tm.tm_min <= 59)
		seq_printf(seq, "%02d:", tm.tm_min);
	else
		seq_puts(seq, "**:");

	if (tm.tm_sec <= 59)
		seq_printf(seq, "%02d\n", tm.tm_sec);
	else
		seq_puts(seq, "**\n");

	seq_printf(seq,
		   "DST_enable\t: %s\n"
		   "BCD\t\t: %s\n"
		   "24hr\t\t: %s\n"
		   "square_wave\t: %s\n"
		   "alarm_IRQ\t: %s\n"
		   "update_IRQ\t: %s\n"
		   "periodic_IRQ\t: %s\n"
		   "periodic_freq\t: %ld\n"
		   "batt_status\t: %s\n",
		   YN(RTC_DST_EN),
		   NY(RTC_DM_BINARY),
		   YN(RTC_24H),
		   YN(RTC_SQWE),
		   YN(RTC_AIE),
		   YN(RTC_UIE),
		   YN(RTC_PIE),
		   freq,
		   batt ? "okay" : "dead");

	return  0;
#undef YN
#undef NY
}

static int rtc_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, rtc_proc_show, NULL);
}
#endif

void rtc_get_rtc_time(struct rtc_time *rtc_tm)
{
	unsigned long uip_watchdog = jiffies, flags;
	unsigned char ctrl;
#ifdef CONFIG_MACH_DECSTATION
	unsigned int real_year;
#endif

	/*
	 * read RTC once any update in progress is done. The update
	 * can take just over 2ms. We wait 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.
	 */

	while (rtc_is_updating() != 0 && jiffies - uip_watchdog < 2*HZ/100)
		cpu_relax();

	/*
	 * Only the values that we read from the RTC are set. We leave
	 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
	 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
	 * only updated by the RTC when initially set to a non-zero value.
	 */
	spin_lock_irqsave(&rtc_lock, flags);
	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);
	/* Only set from 2.6.16 onwards */
	rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);

#ifdef CONFIG_MACH_DECSTATION
	real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
	ctrl = CMOS_READ(RTC_CONTROL);
	spin_unlock_irqrestore(&rtc_lock, 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);
		BCD_TO_BIN(rtc_tm->tm_wday);
	}

#ifdef CONFIG_MACH_DECSTATION
	rtc_tm->tm_year += real_year - 72;
#endif

	/*
	 * 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 += (epoch - 1900)) <= 69)
		rtc_tm->tm_year += 100;

	rtc_tm->tm_mon--;
}

static void get_rtc_alm_time(struct rtc_time *alm_tm)
{
	unsigned char ctrl;

	/*
	 * Only the values that we read from the RTC are set. That
	 * means only tm_hour, tm_min, and tm_sec.
	 */
	spin_lock_irq(&rtc_lock);
	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);
	spin_unlock_irq(&rtc_lock);

	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);
	}
}

#ifdef RTC_IRQ
/*
 * 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 with the interrupt enable/disable bits.
 */

static void mask_rtc_irq_bit_locked(unsigned char bit)
{
	unsigned char val;

	if (hpet_mask_rtc_irq_bit(bit))
		return;
	val = CMOS_READ(RTC_CONTROL);
	val &=  ~bit;
	CMOS_WRITE(val, RTC_CONTROL);
	CMOS_READ(RTC_INTR_FLAGS);

	rtc_irq_data = 0;
}

static void set_rtc_irq_bit_locked(unsigned char bit)
{
	unsigned char val;

	if (hpet_set_rtc_irq_bit(bit))
		return;
	val = CMOS_READ(RTC_CONTROL);
	val |= bit;
	CMOS_WRITE(val, RTC_CONTROL);
	CMOS_READ(RTC_INTR_FLAGS);

	rtc_irq_data = 0;
}
#endif

MODULE_AUTHOR("Paul Gortmaker");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(RTC_MINOR);