Messages in this thread Patch in this message | | | From | Stephen Boyd <> | Subject | [PATCH 1/3] ARM: msm: Stop counting before reprogramming clockevent | Date | Thu, 14 Mar 2013 20:31:37 -0700 |
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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> --- arch/arm/mach-msm/timer.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c index 2969027..f9fd77e 100644 --- a/arch/arm/mach-msm/timer.c +++ b/arch/arm/mach-msm/timer.c @@ -62,7 +62,10 @@ static int msm_timer_set_next_event(unsigned long cycles, { 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(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE); return 0; -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation
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