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Commit 4ae7806f authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[ARM] pxa: Don't wind OSCR backwards over suspend/resume 



OSCR is supposed to monotonically increment; however restoring it
to a time prior to OSMR0 may result in it being wound backwards.
Instead, if OSMR0 is within the minimum expiry time, wind OSMR0
forwards.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a88264c2

arch/arm/mach-pxa/time.c

+12 −9
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ static void __init pxa_timer_init(void) 
}



#ifdef CONFIG_PM

static unsigned long osmr[4], oier;

static unsigned long osmr[4], oier, oscr;



static void pxa_timer_suspend(void)

{
@@ -190,23 +190,26 @@ static void pxa_timer_suspend(void) 
	osmr[2] = OSMR2;

	osmr[3] = OSMR3;

	oier = OIER;

	oscr = OSCR;

}



static void pxa_timer_resume(void)

{

	/*

	 * Ensure that we have at least MIN_OSCR_DELTA between match

	 * register 0 and the OSCR, to guarantee that we will receive

	 * the one-shot timer interrupt.  We adjust OSMR0 in preference

	 * to OSCR to guarantee that OSCR is monotonically incrementing.

	 */

	if (osmr[0] - oscr < MIN_OSCR_DELTA)

		osmr[0] += MIN_OSCR_DELTA;



	OSMR0 = osmr[0];

	OSMR1 = osmr[1];

	OSMR2 = osmr[2];

	OSMR3 = osmr[3];

	OIER = oier;



	/*

	 * OSCR0 is the system timer, which has to increase

	 * monotonically until it rolls over in hardware.  The value

	 * (OSMR0 - LATCH) is OSCR0 at the most recent system tick,

	 * which is a handy value to restore to OSCR0.

	 */

	OSCR = OSMR0 - LATCH;

	OSCR = oscr;

}

#else

#define pxa_timer_suspend NULL