Commit 2a61b0ac authored by Mateusz Jończyk's avatar Mateusz Jończyk Committed by Alexandre Belloni
Browse files

rtc: mc146818-lib: refactor mc146818_get_time 



Refactor mc146818_get_time() so that it uses mc146818_avoid_UIP().

Signed-off-by: default avatarMateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-7-mat.jonczyk@o2.pl
parent ec5895c0

drivers/rtc/rtc-mc146818-lib.c

+42 −67
Original line number Diff line number Diff line
@@ -103,49 +103,20 @@ bool mc146818_does_rtc_work(void) 
}

EXPORT_SYMBOL_GPL(mc146818_does_rtc_work);



unsigned int mc146818_get_time(struct rtc_time *time)

{

struct mc146818_get_time_callback_param {

	struct rtc_time *time;

	unsigned char ctrl;

	unsigned long flags;

	unsigned int iter_count = 0;

	unsigned char century = 0;

	bool retry;



#ifdef CONFIG_ACPI

	unsigned char century;

#endif

#ifdef CONFIG_MACH_DECSTATION

	unsigned int real_year;

#endif

};



again:

	if (iter_count > 10) {

		memset(time, 0, sizeof(*time));

		return -EIO;

	}

	iter_count++;



	spin_lock_irqsave(&rtc_lock, flags);



	/*

	 * Check whether there is an update in progress during which the

	 * readout is unspecified. The maximum update time is ~2ms. Poll

	 * every msec for completion.

	 *

	 * Store the second value before checking UIP so a long lasting NMI

	 * which happens to hit after the UIP check cannot make an update

	 * cycle invisible.

	 */

	time->tm_sec = CMOS_READ(RTC_SECONDS);



	if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {

		spin_unlock_irqrestore(&rtc_lock, flags);

		mdelay(1);

		goto again;

	}



	/* Revalidate the above readout */

	if (time->tm_sec != CMOS_READ(RTC_SECONDS)) {

		spin_unlock_irqrestore(&rtc_lock, flags);

		goto again;

	}

static void mc146818_get_time_callback(unsigned char seconds, void *param_in)

{

	struct mc146818_get_time_callback_param *p = param_in;



	/*

	 * Only the values that we read from the RTC are set. We leave
@@ -153,39 +124,39 @@ unsigned int mc146818_get_time(struct rtc_time *time) 
	 * 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.

	 */

	time->tm_min = CMOS_READ(RTC_MINUTES);

	time->tm_hour = CMOS_READ(RTC_HOURS);

	time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);

	time->tm_mon = CMOS_READ(RTC_MONTH);

	time->tm_year = CMOS_READ(RTC_YEAR);

	p->time->tm_sec = seconds;

	p->time->tm_min = CMOS_READ(RTC_MINUTES);

	p->time->tm_hour = CMOS_READ(RTC_HOURS);

	p->time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);

	p->time->tm_mon = CMOS_READ(RTC_MONTH);

	p->time->tm_year = CMOS_READ(RTC_YEAR);

#ifdef CONFIG_MACH_DECSTATION

	real_year = CMOS_READ(RTC_DEC_YEAR);

	p->real_year = CMOS_READ(RTC_DEC_YEAR);

#endif

#ifdef CONFIG_ACPI

	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&

	    acpi_gbl_FADT.century)

		century = CMOS_READ(acpi_gbl_FADT.century);

	    acpi_gbl_FADT.century) {

		p->century = CMOS_READ(acpi_gbl_FADT.century);

	} else {

		p->century = 0;

	}

#endif

	ctrl = CMOS_READ(RTC_CONTROL);

	/*

	 * Check for the UIP bit again. If it is set now then

	 * the above values may contain garbage.

	 */

	retry = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP;

	/*

	 * A NMI might have interrupted the above sequence so check whether

	 * the seconds value has changed which indicates that the NMI took

	 * longer than the UIP bit was set. Unlikely, but possible and

	 * there is also virt...

	 */

	retry |= time->tm_sec != CMOS_READ(RTC_SECONDS);



	spin_unlock_irqrestore(&rtc_lock, flags);

	p->ctrl = CMOS_READ(RTC_CONTROL);

}



unsigned int mc146818_get_time(struct rtc_time *time)

{

	struct mc146818_get_time_callback_param p = {

		.time = time

	};



	if (retry)

		goto again;

	if (!mc146818_avoid_UIP(mc146818_get_time_callback, &p)) {

		memset(time, 0, sizeof(*time));

		return -EIO;

	}



	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)

	if (!(p.ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)

	{

		time->tm_sec = bcd2bin(time->tm_sec);

		time->tm_min = bcd2bin(time->tm_min);
@@ -193,15 +164,19 @@ unsigned int mc146818_get_time(struct rtc_time *time) 
		time->tm_mday = bcd2bin(time->tm_mday);

		time->tm_mon = bcd2bin(time->tm_mon);

		time->tm_year = bcd2bin(time->tm_year);

		century = bcd2bin(century);

#ifdef CONFIG_ACPI

		p.century = bcd2bin(p.century);

#endif

	}



#ifdef CONFIG_MACH_DECSTATION

	time->tm_year += real_year - 72;

	time->tm_year += p.real_year - 72;

#endif



	if (century > 20)

		time->tm_year += (century - 19) * 100;

#ifdef CONFIG_ACPI

	if (p.century > 20)

		time->tm_year += (p.century - 19) * 100;

#endif



	/*

	 * Account for differences between how the RTC uses the values