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[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: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2007-11-12 22:48:12 +00:00 committed by Russell King
parent a88264c24c
commit 4ae7806f8b
1 changed files with 12 additions and 9 deletions
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21
arch/arm/mach-pxa/time.c
View File

@ -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