linux-kernel - Re: [PATCH v3] drivers/clocksource/mediatek: Ack and disable interrupts on suspend

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Date:   Mon, 19 Apr 2021 10:33:02 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Evan Benn <evanbenn@...omium.org>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     linux-mediatek@...ts.infradead.org,
        Fabien Parent <fparent@...libre.com>,
        Yingjoe Chen <yingjoe.chen@...iatek.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        linux-arm-kernel@...ts.infradead.org,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] drivers/clocksource/mediatek: Ack and disable
 interrupts on suspend

On 12/04/2021 05:22, Evan Benn wrote:
> Interrupts are disabled during suspend before this driver disables its
> timers. ARM trusted firmware will abort suspend if the timer irq is
> pending, so ack and disable the timer interrupt during suspend.
> 
> Signed-off-by: Evan Benn <evanbenn@...omium.org>
> ---
> 
> Changes in v3:
> Move the ACK from the shutdown to the suspend function.
> 
> Changes in v2:
> Remove the patch that splits the drivers into 2 files.
> 
>  drivers/clocksource/timer-mediatek.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
> index 9318edcd8963..1ae8fee639bf 100644
> --- a/drivers/clocksource/timer-mediatek.c
> +++ b/drivers/clocksource/timer-mediatek.c
> @@ -241,6 +241,27 @@ static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
>  	       timer_of_base(to) + GPT_IRQ_EN_REG);
>  }
>  
> +static void mtk_gpt_resume(struct clock_event_device *clk)
> +{
> +	struct timer_of *to = to_timer_of(clk);
> +
> +	mtk_gpt_enable_irq(to, TIMER_CLK_EVT);
> +}
> +
> +static void mtk_gpt_suspend(struct clock_event_device *clk)
> +{
> +	struct timer_of *to = to_timer_of(clk);
> +
> +	/* Disable all interrupts */
> +	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);
> +
> +	/* This is called with interrupts disabled,

Please fix the comment style:

	/*
	 * This is called with interrupts disabled
	 * so ...
	 * ...
	 */

Other than than that I'll be happy to pick it.

> +	 * so we need to ack any interrupt that is pending
> +	 * Or for example ATF will prevent a suspend from completing.
> +	 */
> +	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
> +}
> +
>  static struct timer_of to = {
>  	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
>  
> @@ -286,6 +307,8 @@ static int __init mtk_gpt_init(struct device_node *node)
>  	to.clkevt.set_state_oneshot = mtk_gpt_clkevt_shutdown;
>  	to.clkevt.tick_resume = mtk_gpt_clkevt_shutdown;
>  	to.clkevt.set_next_event = mtk_gpt_clkevt_next_event;
> +	to.clkevt.suspend = mtk_gpt_suspend;
> +	to.clkevt.resume = mtk_gpt_resume;
>  	to.of_irq.handler = mtk_gpt_interrupt;
>  
>  	ret = timer_of_init(node, &to);
> 


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