linux-kernel - Re: [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt leading to crash

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Date:	Thu, 22 Oct 2015 21:50:54 +0200
From:	Matthias Brugger <matthias.bgg@...il.com>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	mingo@...nel.org, Yingjoe Chen <yingjoe.chen@...iatek.com>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-arm-kernel@...ts.infradead.org>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH 1/9] clockevents/drivers/mtk: Fix spurious interrupt
 leading to crash

2015-10-19 22:59 GMT+02:00 Daniel Lezcano <daniel.lezcano@...aro.org>:
> After analysis done by Yingjoe Chen, the timer appears to have a pending
> interrupt when it is enabled.
>
> Fix this by acknowledging the pending interrupt when enabling the timer
> interrupt.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> Tested-by: Yingjoe Chen <yingjoe.chen@...iatek.com>

Acked-by: Matthias Brugger <matthias.bgg@...il.com>

> ---
>  drivers/clocksource/mtk_timer.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
> index 50f0641..c8badc4 100644
> --- a/drivers/clocksource/mtk_timer.c
> +++ b/drivers/clocksource/mtk_timer.c
> @@ -141,14 +141,6 @@ static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
>         return IRQ_HANDLED;
>  }
>
> -static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
> -{
> -       /* Disable all interrupts */
> -       writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
> -       /* Acknowledge all interrupts */
> -       writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
> -}
> -
>  static void
>  mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
>  {
> @@ -168,6 +160,12 @@ static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
>  {
>         u32 val;
>
> +       /* Disable all interrupts */
> +       writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
> +
> +       /* Acknowledge all spurious pending interrupts */
> +       writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
> +
>         val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
>         writel(val | GPT_IRQ_ENABLE(timer),
>                         evt->gpt_base + GPT_IRQ_EN_REG);
> @@ -220,8 +218,6 @@ static void __init mtk_timer_init(struct device_node *node)
>         }
>         rate = clk_get_rate(clk);
>
> -       mtk_timer_global_reset(evt);
> -
>         if (request_irq(evt->dev.irq, mtk_timer_interrupt,
>                         IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
>                 pr_warn("failed to setup irq %d\n", evt->dev.irq);
> --
> 1.9.1
>



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