[PATCH] ARM: sunxi: stop timer from ticking before enabling interrupts

[PATCH] ARM: sunxi: stop timer from ticking before enabling interrupts

[Marc Zyngier]

The sun4i timer can still be ticking when we enable the interrupt.
If another timer is actually used (A7 architected timer, for example),
odds are that the interrupt will eventually fire with the event_handler
pointer being NULL.

The obvious fix it to stop the timer before registering the interrupt.

Observed and tested on sun7i (cubietruck).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/clocksource/sun4i_timer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c
index 2fb4695..a4f6119 100644
--- a/drivers/clocksource/sun4i_timer.c
+++ b/drivers/clocksource/sun4i_timer.c
@@ -179,6 +179,9 @@ static void __init sun4i_timer_init(struct device_node *node)
 	writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
 	       timer_base + TIMER_CTL_REG(0));
 
+	/* Make sure timer is stopped before playing with interrupts */
+	sun4i_clkevt_time_stop(0);
+
 	ret = setup_irq(irq, &sun4i_timer_irq);
 	if (ret)
 		pr_warn("failed to setup irq %d\n", irq);
-- 
1.8.4.3

[PATCH] ARM: sunxi: stop timer from ticking before enabling interrupts

[Maxime Ripard]

Hi Marc,

On Sat, Nov 30, 2013 at 12:53:15PM +0000, Marc Zyngier wrote:
> The sun4i timer can still be ticking when we enable the interrupt.
> If another timer is actually used (A7 architected timer, for example),
> odds are that the interrupt will eventually fire with the event_handler
> pointer being NULL.
> 
> The obvious fix it to stop the timer before registering the interrupt.
> 
> Observed and tested on sun7i (cubietruck).
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

You can add my Acked-by, but you should rather send this to Daniel
Lezcano, which is the clocksource/clockevent maintainer.

Thanks,
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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[PATCH] ARM: sunxi: stop timer from ticking before enabling interrupts

[Marc Zyngier]

On 2013-11-30 14:15, Maxime Ripard wrote:

Hi Maxime,

> On Sat, Nov 30, 2013 at 12:53:15PM +0000, Marc Zyngier wrote:
>> The sun4i timer can still be ticking when we enable the interrupt.
>> If another timer is actually used (A7 architected timer, for 
>> example),
>> odds are that the interrupt will eventually fire with the 
>> event_handler
>> pointer being NULL.
>>
>> The obvious fix it to stop the timer before registering the 
>> interrupt.
>>
>> Observed and tested on sun7i (cubietruck).
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>
> You can add my Acked-by, but you should rather send this to Daniel
> Lezcano, which is the clocksource/clockevent maintainer.

Thanks. I'll push that to Daniel directly.

Cheers,

         M.
-- 
Fast, cheap, reliable. Pick two.