linux-kernel - Re: [PATCH 1/1] pinctrl: amd: disable and mask interrupts on probe

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Date:   Fri, 8 Oct 2021 13:19:17 -0500
From:   "Limonciello, Mario" <mario.limonciello@....com>
To:     Sachi King <nakato@...ato.io>, linux-gpio@...r.kernel.org,
        basavaraj.natikar@....com
Cc:     linux-kernel@...r.kernel.org,
        Shyam-sundar S-k <Shyam-sundar.S-k@....com>,
        "Shah, Nehal-bakulchandra" <Nehal-bakulchandra.Shah@....com>
Subject: Re: [PATCH 1/1] pinctrl: amd: disable and mask interrupts on probe

On 10/1/2021 11:17, Sachi King wrote:
> Some systems such as the Microsoft Surface Laptop 4 leave interrupts
> enabled and configured for use in sleep states on boot, which cause
> unexpected behaviour such as spurious wakes and failed resumes in
> s2idle states.
> 
> As interrupts should not be enabled until they are claimed and
> explicitly enabled, disabling any interrupts mistakenly left enabled by
> firmware should be safe.
> 

So I did test this on a handful of platforms and confirmed that the 
events declared in _AEI are still being enabled and passed properly.

So if no other changes needed you can add my:
Tested-by: Mario Limonciello <mario.limonciello@....com>

> Signed-off-by: Sachi King <nakato@...ato.io>
> ---
>   drivers/pinctrl/pinctrl-amd.c | 29 +++++++++++++++++++++++++++++
>   1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
> index c001f2ed20f8..aa4136cd312d 100644
> --- a/drivers/pinctrl/pinctrl-amd.c
> +++ b/drivers/pinctrl/pinctrl-amd.c
> @@ -830,6 +830,32 @@ static const struct pinconf_ops amd_pinconf_ops = {
>   	.pin_config_group_set = amd_pinconf_group_set,
>   };
>   
> +static void amd_gpio_irq_init(struct amd_gpio *gpio_dev) {
> +	struct pinctrl_desc *desc = gpio_dev->pctrl->desc;
> +	unsigned long flags;
> +	u32 pin_reg, mask;
> +	int i;
> +
> +	mask = BIT(WAKE_CNTRL_OFF_S0I3) | BIT(WAKE_CNTRL_OFF_S3)
> +		| BIT(INTERRUPT_MASK_OFF) | BIT(INTERRUPT_ENABLE_OFF)
> +	        | BIT(INTERRUPT_MASK_OFF) | BIT(WAKE_CNTRL_OFF_S4);
> +
> +	for (i = 0; i < desc->npins; i++) {
> +		int pin = desc->pins[i].number;
> +		const struct pin_desc *pd = pin_desc_get(gpio_dev->pctrl, pin);
> +		if (!pd)
> +			continue;
> +
> +		raw_spin_lock_irqsave(&gpio_dev->lock, flags);
> +
> +		pin_reg = readl(gpio_dev->base + i * 4);
> +		pin_reg &= ~mask;
> +		writel(pin_reg, gpio_dev->base + i * 4);
> +
> +		raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
> +	}
> +}
> +
>   #ifdef CONFIG_PM_SLEEP
>   static bool amd_gpio_should_save(struct amd_gpio *gpio_dev, unsigned int pin)
>   {
> @@ -967,6 +993,9 @@ static int amd_gpio_probe(struct platform_device *pdev)
>   		return PTR_ERR(gpio_dev->pctrl);
>   	}
>   
> +	/* Disable and mask interrupts */
> +	amd_gpio_irq_init(gpio_dev);
> +

As the pinctrl device was just registered, I do wonder if this actually 
needs a mutex in case another thread tries to enable the pins at the 
same time.  I might be wrong here though and things are OK because the 
pin range isn't added until later on in probe.


>   	girq = &gpio_dev->gc.irq;
>   	girq->chip = &amd_gpio_irqchip;
>   	/* This will let us handle the parent IRQ in the driver */
>