linux-kernel - Re: [PATCH v3 2/2] pinctrl: amd: Fix wakeups when IRQ is shared with SCI

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Message-ID: <7e2b79c8-2c49-468b-73f6-258b22ea8945@amd.com>
Date:   Fri, 22 Oct 2021 16:39:07 +0530
From:   Basavaraj Natikar <bnatikar@....com>
To:     Mario Limonciello <mario.limonciello@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Basavaraj Natikar <Basavaraj.Natikar@....com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>
Cc:     "open list:PIN CONTROL SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        Nehal Shah <Nehal-bakulchandra.Shah@....com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Joerie de Gram <j.de.gram@...il.com>
Subject: Re: [PATCH v3 2/2] pinctrl: amd: Fix wakeups when IRQ is shared with
 SCI


On 10/19/2021 9:34 PM, Mario Limonciello wrote:
> On some Lenovo AMD Gen2 platforms the IRQ for the SCI and pinctrl drivers
> are shared.  Due to how the s2idle loop handling works, this case needs
> an extra explicit check whether the interrupt was caused by SCI or by
> the GPIO controller.
>
> To fix this rework the existing IRQ handler function to function as a
> checker and an IRQ handler depending on the calling arguments.
>
> BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1738
> Reported-by: Joerie de Gram <j.de.gram@...il.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> Note:
>  This is *possibly* a fix from fdde0ff8590b, 56b991849009 or other
>  changes in the acpi_s2idle_wake handling, but AMD didn't support
>  s2idle across the kernel widely until 5.14 or later. This is the
>  reason for lack of a fixes tag.
> Changes from v2->v3:
>  * Add new precursor patch for fixing missing ACPI function stubs
>  * Add __maybe_unused for unused function when set with COMPILE_TEST
> Changes from v1->v2:
>  * drop Kconfig changes to drop COMPILE_TEST, instead #ifdef CONFIG_ACPI
>  * fix a logic error during wakeup
>  * Use IRQ_RETVAL()
>  drivers/pinctrl/pinctrl-amd.c | 27 ++++++++++++++++++++++++---
>  1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
> index d19974aceb2e..1272ecd8791f 100644
> --- a/drivers/pinctrl/pinctrl-amd.c
> +++ b/drivers/pinctrl/pinctrl-amd.c
> @@ -598,16 +598,16 @@ static struct irq_chip amd_gpio_irqchip = {
>  
>  #define PIN_IRQ_PENDING	(BIT(INTERRUPT_STS_OFF) | BIT(WAKE_STS_OFF))
>  
> -static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id)
> +static bool _amd_gpio_irq_handler(int irq, void *dev_id)
>  {
>  	struct amd_gpio *gpio_dev = dev_id;
>  	struct gpio_chip *gc = &gpio_dev->gc;
> -	irqreturn_t ret = IRQ_NONE;
>  	unsigned int i, irqnr;
>  	unsigned long flags;
>  	u32 __iomem *regs;
>  	u32  regval;
>  	u64 status, mask;
> +	bool ret = false;

Just a minor nit. Can you do it reverse Xmas?
With that change 

Acked-by: Basavaraj Natikar <Basavaraj.Natikar@....com>


Thanks,
Basavaraj

>  
>  	/* Read the wake status */
>  	raw_spin_lock_irqsave(&gpio_dev->lock, flags);
> @@ -627,6 +627,12 @@ static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id)
>  		/* Each status bit covers four pins */
>  		for (i = 0; i < 4; i++) {
>  			regval = readl(regs + i);
> +			/* called from resume context on a shared IRQ, just
> +			 * checking wake source.
> +			 */
> +			if (irq < 0 && (regval & BIT(WAKE_STS_OFF)))
> +				return true;
> +
>  			if (!(regval & PIN_IRQ_PENDING) ||
>  			    !(regval & BIT(INTERRUPT_MASK_OFF)))
>  				continue;
> @@ -652,9 +658,12 @@ static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id)
>  			}
>  			writel(regval, regs + i);
>  			raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
> -			ret = IRQ_HANDLED;
> +			ret = true;
>  		}
>  	}
> +	/* called from resume context on shared IRQ but didn't cause wake */
> +	if (irq < 0)
> +		return false;
>  
>  	/* Signal EOI to the GPIO unit */
>  	raw_spin_lock_irqsave(&gpio_dev->lock, flags);
> @@ -666,6 +675,16 @@ static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id)
>  	return ret;
>  }
>  
> +static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id)
> +{
> +	return IRQ_RETVAL(_amd_gpio_irq_handler(irq, dev_id));
> +}
> +
> +static bool __maybe_unused amd_gpio_check_wake(void *dev_id)
> +{
> +	return _amd_gpio_irq_handler(-1, dev_id);
> +}
> +
>  static int amd_get_groups_count(struct pinctrl_dev *pctldev)
>  {
>  	struct amd_gpio *gpio_dev = pinctrl_dev_get_drvdata(pctldev);
> @@ -1004,6 +1023,7 @@ static int amd_gpio_probe(struct platform_device *pdev)
>  		goto out2;
>  
>  	platform_set_drvdata(pdev, gpio_dev);
> +	acpi_register_wakeup_handler(gpio_dev->irq, amd_gpio_check_wake, gpio_dev);
>  
>  	dev_dbg(&pdev->dev, "amd gpio driver loaded\n");
>  	return ret;
> @@ -1021,6 +1041,7 @@ static int amd_gpio_remove(struct platform_device *pdev)
>  	gpio_dev = platform_get_drvdata(pdev);
>  
>  	gpiochip_remove(&gpio_dev->gc);
> +	acpi_unregister_wakeup_handler(amd_gpio_check_wake, gpio_dev);
>  
>  	return 0;
>  }