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ARM: msm: Stop counting before reprogramming clockevent 

If the clockevent is forcibly reprogrammed to have a different
match value we mistakenly assume the timer is not ticking and
program a new match value while the timer is running. Although we
clear the timer before programming a new match, it's better to
stop the timer before clearing it so that we're sure the proper
amount of ticks are counted. Failure to do so can lead to missed
ticks and system hangs.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>
This commit is contained in:
Stephen Boyd 2013-03-14 20:31:37 -07:00 committed by David Brown
parent f6161aa153
commit 4080d2d11a
1 changed files with 4 additions and 1 deletions
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5
arch/arm/mach-msm/timer.c
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@ -62,7 +62,10 @@ static int msm_timer_set_next_event(unsigned long cycles,
{ {
u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE); u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
writel_relaxed(0, event_base + TIMER_CLEAR); ctrl &= ~TIMER_ENABLE_EN;
writel_relaxed(ctrl, event_base + TIMER_ENABLE);
writel_relaxed(ctrl, event_base + TIMER_CLEAR);
writel_relaxed(cycles, event_base + TIMER_MATCH_VAL); writel_relaxed(cycles, event_base + TIMER_MATCH_VAL);
writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE); writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE);
return 0; return 0;