Merge branch 'timers-rtc-for-linus' of... (21a32816) · Commits · 戴 / test

Documentation/rtc.txt

+10 −19

Original line number	Diff line number	Diff line
		@@ -178,38 +178,29 @@ RTC class framework, but can't be supported by the older driver.
		setting the longer alarm time and enabling its IRQ using a single
		request (using the same model as EFI firmware).

		* RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, it probably
		also offers update IRQs whenever the "seconds" counter changes.
		If needed, the RTC framework can emulate this mechanism.
		* RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, the RTC framework
		will emulate this mechanism.

		* RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... another
		feature often accessible with an IRQ line is a periodic IRQ, issued
		at settable frequencies (usually 2^N Hz).
		* RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... these icotls
		are emulated via a kernel hrtimer.

		In many cases, the RTC alarm can be a system wake event, used to force
		Linux out of a low power sleep state (or hibernation) back to a fully
		operational state. For example, a system could enter a deep power saving
		state until it's time to execute some scheduled tasks.

		Note that many of these ioctls need not actually be implemented by your
		driver. The common rtc-dev interface handles many of these nicely if your
		driver returns ENOIOCTLCMD. Some common examples:
		Note that many of these ioctls are handled by the common rtc-dev interface.
		Some common examples:

		* RTC_RD_TIME, RTC_SET_TIME: the read_time/set_time functions will be
		called with appropriate values.

		* RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: the
		set_alarm/read_alarm functions will be called.
		* RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: gets or sets
		the alarm rtc_timer. May call the set_alarm driver function.

		* RTC_IRQP_SET, RTC_IRQP_READ: the irq_set_freq function will be called
		to set the frequency while the framework will handle the read for you
		since the frequency is stored in the irq_freq member of the rtc_device
		structure. Your driver needs to initialize the irq_freq member during
		init. Make sure you check the requested frequency is in range of your
		hardware in the irq_set_freq function. If it isn't, return -EINVAL. If
		you cannot actually change the frequency, do not define irq_set_freq.
		* RTC_IRQP_SET, RTC_IRQP_READ: These are emulated by the generic code.

		* RTC_PIE_ON, RTC_PIE_OFF: the irq_set_state function will be called.
		* RTC_PIE_ON, RTC_PIE_OFF: These are also emulated by the generic code.

		If all else fails, check out the rtc-test.c driver!

drivers/rtc/class.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -117,6 +117,7 @@ struct rtc_device rtc_device_register(const char name, struct device *dev,
		struct module *owner)
		{
		struct rtc_device *rtc;
		struct rtc_wkalrm alrm;
		int id, err;

		if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
		@@ -166,6 +167,12 @@ struct rtc_device rtc_device_register(const char name, struct device *dev,
		rtc->pie_timer.function = rtc_pie_update_irq;
		rtc->pie_enabled = 0;

		/* Check to see if there is an ALARM already set in hw */
		err = __rtc_read_alarm(rtc, &alrm);

		if (!err && !rtc_valid_tm(&alrm.time))
		rtc_set_alarm(rtc, &alrm);

		strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
		dev_set_name(&rtc->dev, "rtc%d", id);

drivers/rtc/interface.c

+180 −0

Original line number	Diff line number	Diff line
		@@ -116,6 +116,186 @@ int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
		}
		EXPORT_SYMBOL_GPL(rtc_set_mmss);

		static int rtc_read_alarm_internal(struct rtc_device rtc, struct rtc_wkalrm alarm)
		{
		int err;

		err = mutex_lock_interruptible(&rtc->ops_lock);
		if (err)
		return err;

		if (rtc->ops == NULL)
		err = -ENODEV;
		else if (!rtc->ops->read_alarm)
		err = -EINVAL;
		else {
		memset(alarm, 0, sizeof(struct rtc_wkalrm));
		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
		}

		mutex_unlock(&rtc->ops_lock);
		return err;
		}

		int __rtc_read_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
		{
		int err;
		struct rtc_time before, now;
		int first_time = 1;
		unsigned long t_now, t_alm;
		enum { none, day, month, year } missing = none;
		unsigned days;

		/* The lower level RTC driver may return -1 in some fields,
		* creating invalid alarm->time values, for reasons like:
		*
		* - The hardware may not be capable of filling them in;
		* many alarms match only on time-of-day fields, not
		* day/month/year calendar data.
		*
		* - Some hardware uses illegal values as "wildcard" match
		* values, which non-Linux firmware (like a BIOS) may try
		* to set up as e.g. "alarm 15 minutes after each hour".
		* Linux uses only oneshot alarms.
		*
		* When we see that here, we deal with it by using values from
		* a current RTC timestamp for any missing (-1) values. The
		* RTC driver prevents "periodic alarm" modes.
		*
		* But this can be racey, because some fields of the RTC timestamp
		* may have wrapped in the interval since we read the RTC alarm,
		* which would lead to us inserting inconsistent values in place
		* of the -1 fields.
		*
		* Reading the alarm and timestamp in the reverse sequence
		* would have the same race condition, and not solve the issue.
		*
		* So, we must first read the RTC timestamp,
		* then read the RTC alarm value,
		* and then read a second RTC timestamp.
		*
		* If any fields of the second timestamp have changed
		* when compared with the first timestamp, then we know
		* our timestamp may be inconsistent with that used by
		* the low-level rtc_read_alarm_internal() function.
		*
		* So, when the two timestamps disagree, we just loop and do
		* the process again to get a fully consistent set of values.
		*
		* This could all instead be done in the lower level driver,
		* but since more than one lower level RTC implementation needs it,
		* then it's probably best best to do it here instead of there..
		*/

		/* Get the "before" timestamp */
		err = rtc_read_time(rtc, &before);
		if (err < 0)
		return err;
		do {
		if (!first_time)
		memcpy(&before, &now, sizeof(struct rtc_time));
		first_time = 0;

		/* get the RTC alarm values, which may be incomplete */
		err = rtc_read_alarm_internal(rtc, alarm);
		if (err)
		return err;

		/* full-function RTCs won't have such missing fields */
		if (rtc_valid_tm(&alarm->time) == 0)
		return 0;

		/* get the "after" timestamp, to detect wrapped fields */
		err = rtc_read_time(rtc, &now);
		if (err < 0)
		return err;

		/* note that tm_sec is a "don't care" value here: */
		} while ( before.tm_min != now.tm_min
		\|\| before.tm_hour != now.tm_hour
		\|\| before.tm_mon != now.tm_mon
		\|\| before.tm_year != now.tm_year);

		/* Fill in the missing alarm fields using the timestamp; we
		* know there's at least one since alarm->time is invalid.
		*/
		if (alarm->time.tm_sec == -1)
		alarm->time.tm_sec = now.tm_sec;
		if (alarm->time.tm_min == -1)
		alarm->time.tm_min = now.tm_min;
		if (alarm->time.tm_hour == -1)
		alarm->time.tm_hour = now.tm_hour;

		/* For simplicity, only support date rollover for now */
		if (alarm->time.tm_mday == -1) {
		alarm->time.tm_mday = now.tm_mday;
		missing = day;
		}
		if (alarm->time.tm_mon == -1) {
		alarm->time.tm_mon = now.tm_mon;
		if (missing == none)
		missing = month;
		}
		if (alarm->time.tm_year == -1) {
		alarm->time.tm_year = now.tm_year;
		if (missing == none)
		missing = year;
		}

		/* with luck, no rollover is needed */
		rtc_tm_to_time(&now, &t_now);
		rtc_tm_to_time(&alarm->time, &t_alm);
		if (t_now < t_alm)
		goto done;

		switch (missing) {

		/* 24 hour rollover ... if it's now 10am Monday, an alarm that
		* that will trigger at 5am will do so at 5am Tuesday, which
		* could also be in the next month or year. This is a common
		* case, especially for PCs.
		*/
		case day:
		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
		t_alm += 24 * 60 * 60;
		rtc_time_to_tm(t_alm, &alarm->time);
		break;

		/* Month rollover ... if it's the 31th, an alarm on the 3rd will
		* be next month. An alarm matching on the 30th, 29th, or 28th
		* may end up in the month after that! Many newer PCs support
		* this type of alarm.
		*/
		case month:
		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
		do {
		if (alarm->time.tm_mon < 11)
		alarm->time.tm_mon++;
		else {
		alarm->time.tm_mon = 0;
		alarm->time.tm_year++;
		}
		days = rtc_month_days(alarm->time.tm_mon,
		alarm->time.tm_year);
		} while (days < alarm->time.tm_mday);
		break;

		/* Year rollover ... easy except for leap years! */
		case year:
		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
		do {
		alarm->time.tm_year++;
		} while (rtc_valid_tm(&alarm->time) != 0);
		break;

		default:
		dev_warn(&rtc->dev, "alarm rollover not handled\n");
		}

		done:
		return 0;
		}

		int rtc_read_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
		{
		int err;

drivers/rtc/rtc-at91rm9200.c

+0 −28

Original line number	Diff line number	Diff line
		@@ -183,33 +183,6 @@ static int at91_rtc_setalarm(struct device dev, struct rtc_wkalrm alrm)
		return 0;
		}

		/*
		* Handle commands from user-space
		*/
		static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
		unsigned long arg)
		{
		int ret = 0;

		pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg);

		/* important: scrub old status before enabling IRQs */
		switch (cmd) {
		case RTC_UIE_OFF: /* update off */
		at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
		break;
		case RTC_UIE_ON: /* update on */
		at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
		at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
		break;
		default:
		ret = -ENOIOCTLCMD;
		break;
		}

		return ret;
		}

		static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
		{
		pr_debug("%s(): cmd=%08x\n", __func__, enabled);
		@@ -269,7 +242,6 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
		}

		static const struct rtc_class_ops at91_rtc_ops = {
		.ioctl = at91_rtc_ioctl,
		.read_time = at91_rtc_readtime,
		.set_time = at91_rtc_settime,
		.read_alarm = at91_rtc_readalarm,

drivers/rtc/rtc-at91sam9.c

+0 −28

Original line number	Diff line number	Diff line
		@@ -216,33 +216,6 @@ static int at91_rtc_setalarm(struct device dev, struct rtc_wkalrm alrm)
		return 0;
		}

		/*
		* Handle commands from user-space
		*/
		static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
		unsigned long arg)
		{
		struct sam9_rtc *rtc = dev_get_drvdata(dev);
		int ret = 0;
		u32 mr = rtt_readl(rtc, MR);

		dev_dbg(dev, "ioctl: cmd=%08x, arg=%08lx, mr %08x\n", cmd, arg, mr);

		switch (cmd) {
		case RTC_UIE_OFF: /* update off */
		rtt_writel(rtc, MR, mr & ~AT91_RTT_RTTINCIEN);
		break;
		case RTC_UIE_ON: /* update on */
		rtt_writel(rtc, MR, mr \| AT91_RTT_RTTINCIEN);
		break;
		default:
		ret = -ENOIOCTLCMD;
		break;
		}

		return ret;
		}

		static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
		{
		struct sam9_rtc *rtc = dev_get_drvdata(dev);
		@@ -303,7 +276,6 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *_rtc)
		}

		static const struct rtc_class_ops at91_rtc_ops = {
		.ioctl = at91_rtc_ioctl,
		.read_time = at91_rtc_readtime,
		.set_time = at91_rtc_settime,
		.read_alarm = at91_rtc_readalarm,

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