linux-kernel - Re: [PATCH v3 24/24] platform/chrome: cros_ec: Use PM subsystem to manage wakeirq

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Message-ID: <ZYxgQn8L7ENkc0AJ@smile.fi.intel.com>
Date: Wed, 27 Dec 2023 19:34:58 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Mark Hasemeyer <markhas@...omium.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Rob Herring <robh@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Sudeep Holla <sudeep.holla@....com>,
	Raul Rangel <rrangel@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>,
	Benson Leung <bleung@...omium.org>,
	Bhanu Prakash Maiya <bhanumaiya@...omium.org>,
	Chen-Yu Tsai <wenst@...omium.org>,
	Guenter Roeck <groeck@...omium.org>, Lee Jones <lee@...nel.org>,
	Prashant Malani <pmalani@...omium.org>,
	Rob Barnes <robbarnes@...gle.com>,
	Stephen Boyd <swboyd@...omium.org>, chrome-platform@...ts.linux.dev
Subject: Re: [PATCH v3 24/24] platform/chrome: cros_ec: Use PM subsystem to
 manage wakeirq

On Tue, Dec 26, 2023 at 12:21:28PM -0700, Mark Hasemeyer wrote:
> The cros ec driver is manually managing the wake IRQ by calling
> enable_irq_wake()/disable_irq_wake() during suspend/resume.
> 
> Modify the driver to use the power management subsystem to manage the
> wakeirq.
> 
> Rather than assuming that the IRQ is wake capable, use the underlying
> firmware/device tree to determine whether or not to enable it as a wake
> source. Some Chromebooks rely solely on the ec_sync pin to wake the AP
> but do not specify the interrupt as wake capable in the ACPI _CRS. For
> LPC/ACPI based systems a DMI quirk is introduced listing boards whose
> firmware should not be trusted to provide correct wake capable values.
> For device tree base systems, it is not an issue as the relevant device
> tree entries have been updated and DTS is built from source for each
> ChromeOS update.

...

>  	acpi_status status;
>  	struct cros_ec_device *ec_dev;
> +	struct resource irqres;

	struct resource irqres = {};

?

>  	u8 buf[2] = {};
>  	int irq, ret;

...

> -	irq = platform_get_irq_optional(pdev, 0);
> -	if (irq > 0)
> +	irq = platform_get_irq_resource_optional(pdev, 0, &irqres);
> +	if (irq > 0) {
>  		ec_dev->irq = irq;
> -	else if (irq != -ENXIO) {
> +		if (should_force_irq_wake_capable())
> +			ec_dev->irq_wake = true;
> +		else
> +			ec_dev->irq_wake = irqres.flags & IORESOURCE_IRQ_WAKECAPABLE;
> +	} else if (irq != -ENXIO) {
>  		dev_err(dev, "couldn't retrieve IRQ number (%d)\n", irq);
>  		return irq;
>  	}

Still I do not like ambiguity behind irq > 0 vs. irqres.start.

For this, and if needed others, return plain error.
Seems I gave the tag for the previous patch, consider
that tag conditional (it seems I missed this).

...

>  	u16 proto_version;
>  	void *priv;
>  	int irq;
> +	bool irq_wake;
>  	u8 *din;
>  	u8 *dout;
>  	int din_size;
>  	int dout_size;
> -	bool wake_enabled;
>  	bool suspended;
>  	int (*cmd_xfer)(struct cros_ec_device *ec,
>  			struct cros_ec_command *msg);

Have you run pahole on this (before and after)?

-- 
With Best Regards,
Andy Shevchenko