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authorWill Deacon <will.deacon@arm.com>2013-03-28 14:17:55 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-04-03 19:45:50 +0400
commit6f3d90e55660ba42301b5e9c7eed332cc9f70fd7 (patch)
tree0f5ef09981f5322d80a79a12125d291adaab175b /arch/arm/lib
parent93dc68876b608da041fe40ed39424b0fcd5aa2fb (diff)
downloadlinux-6f3d90e55660ba42301b5e9c7eed332cc9f70fd7.tar.xz
ARM: 7685/1: delay: use private ticks_per_jiffy field for timer-based delay ops
Commit 70264367a243 ("ARM: 7653/2: do not scale loops_per_jiffy when using a constant delay clock") fixed a problem with our timer-based delay loop, where loops_per_jiffy is scaled by cpufreq yet used directly by the timer delay ops. This patch fixes the problem in a more elegant way by keeping a private ticks_per_jiffy field in the delay ops, independent of loops_per_jiffy and therefore not subject to scaling. The loop-based delay continues to use loops_per_jiffy directly, as it should. Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/lib')
-rw-r--r--arch/arm/lib/delay.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/arm/lib/delay.c b/arch/arm/lib/delay.c
index 6b93f6a1a3c7..64dbfa57204a 100644
--- a/arch/arm/lib/delay.c
+++ b/arch/arm/lib/delay.c
@@ -58,7 +58,7 @@ static void __timer_delay(unsigned long cycles)
static void __timer_const_udelay(unsigned long xloops)
{
unsigned long long loops = xloops;
- loops *= loops_per_jiffy;
+ loops *= arm_delay_ops.ticks_per_jiffy;
__timer_delay(loops >> UDELAY_SHIFT);
}
@@ -73,11 +73,13 @@ void __init register_current_timer_delay(const struct delay_timer *timer)
pr_info("Switching to timer-based delay loop\n");
delay_timer = timer;
lpj_fine = timer->freq / HZ;
- loops_per_jiffy = lpj_fine;
+
+ /* cpufreq may scale loops_per_jiffy, so keep a private copy */
+ arm_delay_ops.ticks_per_jiffy = lpj_fine;
arm_delay_ops.delay = __timer_delay;
arm_delay_ops.const_udelay = __timer_const_udelay;
arm_delay_ops.udelay = __timer_udelay;
- arm_delay_ops.const_clock = true;
+
delay_calibrated = true;
} else {
pr_info("Ignoring duplicate/late registration of read_current_timer delay\n");