linux-kernel - Re: [PATCH 2/2] pinctrl: mediatek: Update cur

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Date:   Mon, 13 May 2019 15:29:53 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Nicolas Boichat <drinkcat@...omium.org>,
        linux-mediatek@...ts.infradead.org
Cc:     Sean Wang <sean.wang@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-gpio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Chuanjia Liu <Chuanjia.Liu@...iatek.com>, evgreen@...omium.org
Subject: Re: [PATCH 2/2] pinctrl: mediatek: Update cur_mask in mask/mask ops

Quoting Nicolas Boichat (2019-04-28 20:55:15)
> During suspend/resume, mtk_eint_mask may be called while
> wake_mask is active. For example, this happens if a wake-source
> with an active interrupt handler wakes the system:
> irq/pm.c:irq_pm_check_wakeup would disable the interrupt, so
> that it can be handled later on in the resume flow.
> 
> However, this may happen before mtk_eint_do_resume is called:
> in this case, wake_mask is loaded, and cur_mask is restored
> from an older copy, re-enabling the interrupt, and causing
> an interrupt storm (especially for level interrupts).
> 
> Instead, we just record mask/unmask changes in cur_mask. This
> also avoids the need to read the current mask in eint_do_suspend,
> and we can remove mtk_eint_chip_read_mask function.
> 
> Signed-off-by: Nicolas Boichat <drinkcat@...omium.org>

It looks an awful lot like you should just use IRQCHIP_MASK_ON_SUSPEND
here. Isn't that what's happening? All non-wake irqs should be masked at
the hardware level so they can't cause a wakeup during suspend and on
resume they can be unmasked?

> diff --git a/drivers/pinctrl/mediatek/mtk-eint.c b/drivers/pinctrl/mediatek/mtk-eint.c
> index 737385e86beb807..7e526bcf5e0b55c 100644
> --- a/drivers/pinctrl/mediatek/mtk-eint.c
> +++ b/drivers/pinctrl/mediatek/mtk-eint.c
> @@ -113,6 +113,8 @@ static void mtk_eint_mask(struct irq_data *d)
>         void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
>                                                 eint->regs->mask_set);
>  
> +       eint->cur_mask[d->hwirq >> 5] &= ~mask;
> +
>         writel(mask, reg);
>  }
>  
> @@ -123,6 +125,8 @@ static void mtk_eint_unmask(struct irq_data *d)
>         void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
>                                                 eint->regs->mask_clr);
>  
> +       eint->cur_mask[d->hwirq >> 5] |= mask;
> +
>         writel(mask, reg);
>  
>         if (eint->dual_edge[d->hwirq])
> @@ -384,7 +375,6 @@ static void mtk_eint_irq_handler(struct irq_desc *desc)
>  
>  int mtk_eint_do_suspend(struct mtk_eint *eint)
>  {
> -       mtk_eint_chip_read_mask(eint, eint->base, eint->cur_mask);
>         mtk_eint_chip_write_mask(eint, eint->base, eint->wake_mask);
>  


This alone looks like, write out the mask to only allow wake interrupts.