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

[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
No related merge requests found
...@@ -181,7 +181,7 @@ static void __init pxa_timer_init(void) ...@@ -181,7 +181,7 @@ static void __init pxa_timer_init(void)
} }
#ifdef CONFIG_PM #ifdef CONFIG_PM
static unsigned long osmr[4], oier; static unsigned long osmr[4], oier, oscr;
static void pxa_timer_suspend(void) static void pxa_timer_suspend(void)
{ {
...@@ -190,23 +190,26 @@ static void pxa_timer_suspend(void) ...@@ -190,23 +190,26 @@ static void pxa_timer_suspend(void)
osmr[2] = OSMR2; osmr[2] = OSMR2;
osmr[3] = OSMR3; osmr[3] = OSMR3;
oier = OIER; oier = OIER;
oscr = OSCR;
} }
static void pxa_timer_resume(void) 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]; OSMR0 = osmr[0];
OSMR1 = osmr[1]; OSMR1 = osmr[1];
OSMR2 = osmr[2]; OSMR2 = osmr[2];
OSMR3 = osmr[3]; OSMR3 = osmr[3];
OIER = oier; OIER = oier;
OSCR = oscr;
/*
* 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;
} }
#else #else
#define pxa_timer_suspend NULL #define pxa_timer_suspend NULL
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment