linux-kernel - Re: [PATCH 2/2] clocksource/drivers/fttmr010: Be stricter on IRQs

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Date:   Fri, 20 Aug 2021 10:53:22 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org,
        Cédric Le Goater <clg@...d.org>,
        Joel Stanley <joel@....id.au>
Subject: Re: [PATCH 2/2] clocksource/drivers/fttmr010: Be stricter on IRQs

On 25/07/2021 00:44, Linus Walleij wrote:
> Make sure we check that the right interrupt occurred before
> calling the event handler for timer 1. Report spurious IRQs
> as IRQ_NONE.

Does it not mean there is something wrong with the initial setup ?


> Cc: Cédric Le Goater <clg@...d.org>
> Cc: Joel Stanley <joel@....id.au>
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
>  drivers/clocksource/timer-fttmr010.c | 32 +++++++++++++++++++++-------
>  1 file changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clocksource/timer-fttmr010.c b/drivers/clocksource/timer-fttmr010.c
> index 126fb1f259b2..de29d424ec95 100644
> --- a/drivers/clocksource/timer-fttmr010.c
> +++ b/drivers/clocksource/timer-fttmr010.c
> @@ -253,20 +253,36 @@ static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
>   */
>  static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
>  {
> -	struct clock_event_device *evt = dev_id;
> +	struct fttmr010 *fttmr010 = dev_id;
> +	struct clock_event_device *evt = &fttmr010->clkevt;
> +	u32 val;
> +
> +	val = readl(fttmr010->base + TIMER_INTR_STATE);
> +	if (val & (TIMER_1_INT_MATCH1 | TIMER_1_INT_OVERFLOW))
> +		evt->event_handler(evt);
> +	else
> +		/* Spurious IRQ */
> +		return IRQ_NONE;
>  
> -	evt->event_handler(evt);
>  	return IRQ_HANDLED;
>  }
>  
>  static irqreturn_t ast2600_timer_interrupt(int irq, void *dev_id)
>  {
> -	struct clock_event_device *evt = dev_id;
> -	struct fttmr010 *fttmr010 = to_fttmr010(evt);
> +	struct fttmr010 *fttmr010 = dev_id;
> +	struct clock_event_device *evt = &fttmr010->clkevt;
> +	u32 val;
>  
> -	writel(0x1, fttmr010->base + TIMER_INTR_STATE);
> +	val = readl(fttmr010->base + TIMER_INTR_STATE);
> +	if (val & (TIMER_1_INT_MATCH1 | TIMER_1_INT_OVERFLOW)) {
> +		writel(TIMER_1_INT_MATCH1, fttmr010->base + TIMER_INTR_STATE);
> +		evt->event_handler(evt);
> +	} else {
> +		/* Just clear any spurious IRQs from the block */
> +		writel(val, fttmr010->base + TIMER_INTR_STATE);
> +		return IRQ_NONE;
> +	}
>  
> -	evt->event_handler(evt);
>  	return IRQ_HANDLED;
>  }
>  
> @@ -384,12 +400,12 @@ static int __init fttmr010_common_init(struct device_node *np,
>  		fttmr010->timer_shutdown = ast2600_timer_shutdown;
>  		ret = request_irq(irq, ast2600_timer_interrupt,
>  				  IRQF_TIMER, "FTTMR010-TIMER1",
> -				  &fttmr010->clkevt);
> +				  fttmr010);
>  	} else {
>  		fttmr010->timer_shutdown = fttmr010_timer_shutdown;
>  		ret = request_irq(irq, fttmr010_timer_interrupt,
>  				  IRQF_TIMER, "FTTMR010-TIMER1",
> -				  &fttmr010->clkevt);
> +				  fttmr010);
>  	}
>  	if (ret) {
>  		pr_err("FTTMR010-TIMER1 no IRQ\n");
> 


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