rtc-cmos.c

linux 内核源代码

	spin_lock(&rtc_lock);
	irqstat = CMOS_READ(RTC_INTR_FLAGS);
	irqstat &= (CMOS_READ(RTC_CONTROL) & RTC_IRQMASK) | RTC_IRQF;
	spin_unlock(&rtc_lock);

	if (is_intr(irqstat)) {
		rtc_update_irq(p, 1, irqstat);
		return IRQ_HANDLED;
	} else
		return IRQ_NONE;
}

#ifdef	CONFIG_PNP
#define	is_pnp()	1
#define	INITSECTION

#else
#define	is_pnp()	0
#define	INITSECTION	__init
#endif

static int INITSECTION
cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
{
	struct cmos_rtc_board_info	*info = dev->platform_data;
	int				retval = 0;
	unsigned char			rtc_control;

	/* there can be only one ... */
	if (cmos_rtc.dev)
		return -EBUSY;

	if (!ports)
		return -ENODEV;

	/* Claim I/O ports ASAP, minimizing conflict with legacy driver.
	 *
	 * REVISIT non-x86 systems may instead use memory space resources
	 * (needing ioremap etc), not i/o space resources like this ...
	 */
	ports = request_region(ports->start,
			ports->end + 1 - ports->start,
			driver_name);
	if (!ports) {
		dev_dbg(dev, "i/o registers already in use\n");
		return -EBUSY;
	}

	cmos_rtc.irq = rtc_irq;
	cmos_rtc.iomem = ports;

	/* For ACPI systems extension info comes from the FADT.  On others,
	 * board specific setup provides it as appropriate.  Systems where
	 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
	 * some almost-clones) can provide hooks to make that behave.
	 */
	if (info) {
		cmos_rtc.day_alrm = info->rtc_day_alarm;
		cmos_rtc.mon_alrm = info->rtc_mon_alarm;
		cmos_rtc.century = info->rtc_century;

		if (info->wake_on && info->wake_off) {
			cmos_rtc.wake_on = info->wake_on;
			cmos_rtc.wake_off = info->wake_off;
		}
	}

	cmos_rtc.rtc = rtc_device_register(driver_name, dev,
				&cmos_rtc_ops, THIS_MODULE);
	if (IS_ERR(cmos_rtc.rtc)) {
		retval = PTR_ERR(cmos_rtc.rtc);
		goto cleanup0;
	}

	cmos_rtc.dev = dev;
	dev_set_drvdata(dev, &cmos_rtc);
	rename_region(ports, cmos_rtc.rtc->dev.bus_id);

	spin_lock_irq(&rtc_lock);

	/* force periodic irq to CMOS reset default of 1024Hz;
	 *
	 * REVISIT it's been reported that at least one x86_64 ALI mobo
	 * doesn't use 32KHz here ... for portability we might need to
	 * do something about other clock frequencies.
	 */
	CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
	cmos_rtc.rtc->irq_freq = 1024;

	/* disable irqs.
	 *
	 * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
	 * allegedly some older rtcs need that to handle irqs properly
	 */
	rtc_control = CMOS_READ(RTC_CONTROL);
	rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
	CMOS_WRITE(rtc_control, RTC_CONTROL);
	CMOS_READ(RTC_INTR_FLAGS);

	spin_unlock_irq(&rtc_lock);

	/* FIXME teach the alarm code how to handle binary mode;
	 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
	 */
	if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) {
		dev_dbg(dev, "only 24-hr BCD mode supported\n");
		retval = -ENXIO;
		goto cleanup1;
	}

	if (is_valid_irq(rtc_irq))
		retval = request_irq(rtc_irq, cmos_interrupt, IRQF_DISABLED,
				cmos_rtc.rtc->dev.bus_id,
				cmos_rtc.rtc);
	if (retval < 0) {
		dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
		goto cleanup1;
	}

	/* REVISIT optionally make 50 or 114 bytes NVRAM available,
	 * like rtc-ds1553, rtc-ds1742 ... this will often include
	 * registers for century, and day/month alarm.
	 */

	pr_info("%s: alarms up to one %s%s\n",
			cmos_rtc.rtc->dev.bus_id,
			is_valid_irq(rtc_irq)
				?  (cmos_rtc.mon_alrm
					? "year"
					: (cmos_rtc.day_alrm
						? "month" : "day"))
				: "no",
			cmos_rtc.century ? ", y3k" : ""
			);

	return 0;

cleanup1:
	cmos_rtc.dev = NULL;
	rtc_device_unregister(cmos_rtc.rtc);
cleanup0:
	release_region(ports->start, ports->end + 1 - ports->start);
	return retval;
}

static void cmos_do_shutdown(void)
{
	unsigned char	rtc_control;

	spin_lock_irq(&rtc_lock);
	rtc_control = CMOS_READ(RTC_CONTROL);
	rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
	CMOS_WRITE(rtc_control, RTC_CONTROL);
	CMOS_READ(RTC_INTR_FLAGS);
	spin_unlock_irq(&rtc_lock);
}

static void __exit cmos_do_remove(struct device *dev)
{
	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
	struct resource *ports;

	cmos_do_shutdown();

	if (is_valid_irq(cmos->irq))
		free_irq(cmos->irq, cmos->rtc);

	rtc_device_unregister(cmos->rtc);
	cmos->rtc = NULL;

	ports = cmos->iomem;
	release_region(ports->start, ports->end + 1 - ports->start);
	cmos->iomem = NULL;

	cmos->dev = NULL;
	dev_set_drvdata(dev, NULL);
}

#ifdef	CONFIG_PM

static int cmos_suspend(struct device *dev, pm_message_t mesg)
{
	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
	int		do_wake = device_may_wakeup(dev);
	unsigned char	tmp;

	/* only the alarm might be a wakeup event source */
	spin_lock_irq(&rtc_lock);
	cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
		unsigned char	irqstat;

		if (do_wake)
			tmp &= ~(RTC_PIE|RTC_UIE);
		else
			tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
		CMOS_WRITE(tmp, RTC_CONTROL);
		irqstat = CMOS_READ(RTC_INTR_FLAGS);
		irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
		if (is_intr(irqstat))
			rtc_update_irq(cmos->rtc, 1, irqstat);
	}
	spin_unlock_irq(&rtc_lock);

	if (tmp & RTC_AIE) {
		cmos->enabled_wake = 1;
		if (cmos->wake_on)
			cmos->wake_on(dev);
		else
			enable_irq_wake(cmos->irq);
	}

	pr_debug("%s: suspend%s, ctrl %02x\n",
			cmos_rtc.rtc->dev.bus_id,
			(tmp & RTC_AIE) ? ", alarm may wake" : "",
			tmp);

	return 0;
}

static int cmos_resume(struct device *dev)
{
	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
	unsigned char	tmp = cmos->suspend_ctrl;

	/* re-enable any irqs previously active */
	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {

		if (cmos->enabled_wake) {
			if (cmos->wake_off)
				cmos->wake_off(dev);
			else
				disable_irq_wake(cmos->irq);
			cmos->enabled_wake = 0;
		}

		spin_lock_irq(&rtc_lock);
		CMOS_WRITE(tmp, RTC_CONTROL);
		tmp = CMOS_READ(RTC_INTR_FLAGS);
		tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
		if (is_intr(tmp))
			rtc_update_irq(cmos->rtc, 1, tmp);
		spin_unlock_irq(&rtc_lock);
	}

	pr_debug("%s: resume, ctrl %02x\n",
			cmos_rtc.rtc->dev.bus_id,
			cmos->suspend_ctrl);


	return 0;
}

#else
#define	cmos_suspend	NULL
#define	cmos_resume	NULL
#endif

/*----------------------------------------------------------------*/

/* The "CMOS" RTC normally lives on the platform_bus.  On ACPI systems,
 * the device node will always be created as a PNPACPI device.  Plus
 * pre-ACPI PCs probably list it in the PNPBIOS tables.
 */

#ifdef	CONFIG_PNP

#include <linux/pnp.h>

static int __devinit
cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
{
	/* REVISIT paranoia argues for a shutdown notifier, since PNP
	 * drivers can't provide shutdown() methods to disable IRQs.
	 * Or better yet, fix PNP to allow those methods...
	 */
	if (pnp_port_start(pnp,0) == 0x70 && !pnp_irq_valid(pnp,0))
		/* Some machines contain a PNP entry for the RTC, but
		 * don't define the IRQ. It should always be safe to
		 * hardcode it in these cases
		 */
		return cmos_do_probe(&pnp->dev, &pnp->res.port_resource[0], 8);
	else
		return cmos_do_probe(&pnp->dev,
				     &pnp->res.port_resource[0],
				     pnp->res.irq_resource[0].start);
}

static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
{
	cmos_do_remove(&pnp->dev);
}

#ifdef	CONFIG_PM

static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
{
	return cmos_suspend(&pnp->dev, mesg);
}

static int cmos_pnp_resume(struct pnp_dev *pnp)
{
	return cmos_resume(&pnp->dev);
}

#else
#define	cmos_pnp_suspend	NULL
#define	cmos_pnp_resume		NULL
#endif


static const struct pnp_device_id rtc_ids[] = {
	{ .id = "PNP0b00", },
	{ .id = "PNP0b01", },
	{ .id = "PNP0b02", },
	{ },
};
MODULE_DEVICE_TABLE(pnp, rtc_ids);

static struct pnp_driver cmos_pnp_driver = {
	.name		= (char *) driver_name,
	.id_table	= rtc_ids,
	.probe		= cmos_pnp_probe,
	.remove		= __exit_p(cmos_pnp_remove),

	/* flag ensures resume() gets called, and stops syslog spam */
	.flags		= PNP_DRIVER_RES_DO_NOT_CHANGE,
	.suspend	= cmos_pnp_suspend,
	.resume		= cmos_pnp_resume,
};

static int __init cmos_init(void)
{
	return pnp_register_driver(&cmos_pnp_driver);
}
module_init(cmos_init);

static void __exit cmos_exit(void)
{
	pnp_unregister_driver(&cmos_pnp_driver);
}
module_exit(cmos_exit);

#else	/* no PNP */

/*----------------------------------------------------------------*/

/* Platform setup should have set up an RTC device, when PNP is
 * unavailable ... this could happen even on (older) PCs.
 */

static int __init cmos_platform_probe(struct platform_device *pdev)
{
	return cmos_do_probe(&pdev->dev,
			platform_get_resource(pdev, IORESOURCE_IO, 0),
			platform_get_irq(pdev, 0));
}

static int __exit cmos_platform_remove(struct platform_device *pdev)
{
	cmos_do_remove(&pdev->dev);
	return 0;
}

static void cmos_platform_shutdown(struct platform_device *pdev)
{
	cmos_do_shutdown();
}

static struct platform_driver cmos_platform_driver = {
	.remove		= __exit_p(cmos_platform_remove),
	.shutdown	= cmos_platform_shutdown,
	.driver = {
		.name		= (char *) driver_name,
		.suspend	= cmos_suspend,
		.resume		= cmos_resume,
	}
};

static int __init cmos_init(void)
{
	return platform_driver_probe(&cmos_platform_driver,
			cmos_platform_probe);
}
module_init(cmos_init);

static void __exit cmos_exit(void)
{
	platform_driver_unregister(&cmos_platform_driver);
}
module_exit(cmos_exit);


#endif	/* !PNP */

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
MODULE_LICENSE("GPL");