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Commit da2468b6 authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
Browse files

[PATCH] RTC: Remove RTC UIP synchronization on MIPS MC146818 



Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 4af6ec46

include/asm-mips/mc146818-time.h

+2 −31
Original line number Diff line number Diff line
@@ -86,43 +86,14 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime) 
	return retval;

}



/*

 * Returns true if a clock update is in progress

 */

static inline unsigned char rtc_is_updating(void)

{

	unsigned char uip;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);

	spin_unlock_irqrestore(&rtc_lock, flags);

	return uip;

}



static inline unsigned long mc146818_get_cmos_time(void)

{

	unsigned int year, mon, day, hour, min, sec;

	int i;

	unsigned long flags;



	/*

	 * The Linux interpretation of the CMOS clock register contents:

	 * When the Update-In-Progress (UIP) flag goes from 1 to 0, the

	 * RTC registers show the second which has precisely just started.

	 * Let's hope other operating systems interpret the RTC the same way.

	 */



	/* read RTC exactly on falling edge of update flag */

	for (i = 0 ; i < 1000000 ; i++)	/* may take up to 1 second... */

		if (rtc_is_updating())

			break;

	for (i = 0 ; i < 1000000 ; i++)	/* must try at least 2.228 ms */

		if (!rtc_is_updating())

			break;



	spin_lock_irqsave(&rtc_lock, flags);

	do { /* Isn't this overkill ? UIP above should guarantee consistency */



	do {

		sec = CMOS_READ(RTC_SECONDS);

		min = CMOS_READ(RTC_MINUTES);

		hour = CMOS_READ(RTC_HOURS);