aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm
diff options
context:
space:
mode:
authorRussell King <rmk@dyn-67.arm.linux.org.uk>2007-11-12 17:48:12 -0500
committerRussell King <rmk+kernel@arm.linux.org.uk>2008-01-26 10:07:51 -0500
commit4ae7806f8b4bf9a1e74c82f3bd4e91d59bd3d697 (patch)
tree921c819cfa93d70a3e2c5bad328a20c24e3683b3 /arch/arm
parenta88264c24c44924a549f3d596b86d611b7ee9909 (diff)
[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>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mach-pxa/time.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
index 3c4abbf31803..ac0bbad35238 100644
--- a/arch/arm/mach-pxa/time.c
+++ b/arch/arm/mach-pxa/time.c
@@ -181,7 +181,7 @@ static void __init pxa_timer_init(void)
181} 181}
182 182
183#ifdef CONFIG_PM 183#ifdef CONFIG_PM
184static unsigned long osmr[4], oier; 184static unsigned long osmr[4], oier, oscr;
185 185
186static void pxa_timer_suspend(void) 186static void pxa_timer_suspend(void)
187{ 187{
@@ -190,23 +190,26 @@ static void pxa_timer_suspend(void)
190 osmr[2] = OSMR2; 190 osmr[2] = OSMR2;
191 osmr[3] = OSMR3; 191 osmr[3] = OSMR3;
192 oier = OIER; 192 oier = OIER;
193 oscr = OSCR;
193} 194}
194 195
195static void pxa_timer_resume(void) 196static void pxa_timer_resume(void)
196{ 197{
198 /*
199 * Ensure that we have at least MIN_OSCR_DELTA between match
200 * register 0 and the OSCR, to guarantee that we will receive
201 * the one-shot timer interrupt. We adjust OSMR0 in preference
202 * to OSCR to guarantee that OSCR is monotonically incrementing.
203 */
204 if (osmr[0] - oscr < MIN_OSCR_DELTA)
205 osmr[0] += MIN_OSCR_DELTA;
206
197 OSMR0 = osmr[0]; 207 OSMR0 = osmr[0];
198 OSMR1 = osmr[1]; 208 OSMR1 = osmr[1];
199 OSMR2 = osmr[2]; 209 OSMR2 = osmr[2];
200 OSMR3 = osmr[3]; 210 OSMR3 = osmr[3];
201 OIER = oier; 211 OIER = oier;
202 212 OSCR = oscr;
203 /*
204 * OSCR0 is the system timer, which has to increase
205 * monotonically until it rolls over in hardware. The value
206 * (OSMR0 - LATCH) is OSCR0 at the most recent system tick,
207 * which is a handy value to restore to OSCR0.
208 */
209 OSCR = OSMR0 - LATCH;
210} 213}
211#else 214#else
212#define pxa_timer_suspend NULL 215#define pxa_timer_suspend NULL