Module: xenomai-head
Branch: master
Commit: 2442425ef628583485ece62cd637c1e6be500514
URL:
http://git.xenomai.org/?p=xenomai-head.git;a=commit;h=2442425ef628583485ece62cd637c1e6be500514
Author: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
Date: Wed May 25 21:27:00 2011 +0200
arm hal: fix timer programmation calibration
On machines where it is real fast, we may obtain falsely negative
durations.
---
ksrc/arch/arm/hal.c | 9 ++++++---
1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/ksrc/arch/arm/hal.c b/ksrc/arch/arm/hal.c
index 31606c1..4794c4c 100644
--- a/ksrc/arch/arm/hal.c
+++ b/ksrc/arch/arm/hal.c
@@ -100,8 +100,9 @@ unsigned long rthal_timer_calibrate(void)
{
unsigned long long start, end, sum = 0, sum_sq = 0;
volatile unsigned const_delay = 0xffffffff;
- unsigned int delay = const_delay, diff;
unsigned long result, flags, tsc_lat;
+ unsigned int delay = const_delay;
+ long long diff;
int i, j;
flags = rthal_critical_enter(NULL);
@@ -131,8 +132,10 @@ unsigned long rthal_timer_calibrate(void)
barrier();
rthal_read_tsc(end);
diff = end - start - tsc_lat;
- sum += diff;
- sum_sq += diff * diff;
+ if (diff > 0) {
+ sum += diff;
+ sum_sq += diff * diff;
+ }
}
}
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