linux-kernel - Re: [PATCH v5 1/2] driver core: auxiliary bus: Introduce auxiliary device resource management

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aCSOYRJXaiJpch6u@smile.fi.intel.com>
Date: Wed, 14 May 2025 15:36:49 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Raag Jadav <raag.jadav@...el.com>
Cc: gregkh@...uxfoundation.org, david.m.ertman@...el.com,
	ira.weiny@...el.com, lee@...nel.org,
	mika.westerberg@...ux.intel.com, heikki.krogerus@...ux.intel.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 1/2] driver core: auxiliary bus: Introduce auxiliary
 device resource management

On Wed, May 14, 2025 at 05:54:31PM +0530, Raag Jadav wrote:
> With more and more drivers adopting to auxiliary bus infrastructure comes
> the need for managing resources at auxiliary device level. This is useful
> for cases where parent device shares variable number and type of resources
> with auxiliary child device but doesn't require any active involvement in
> managing them.
> 
> This reduces potential duplication of resource APIs that may be required by
> parent device driver. With this in place parent driver will be responsible
> for filling up respective resources and its count in auxiliary device
> structure before registering it, so that the leaf drivers can utilize in
> their probe function. Lifecycle of these resources will be as long as the
> auxiliary device exists.

...

> +/**
> + * auxiliary_get_irq_optional - get an optional IRQ for auxiliary device
> + * @auxdev: auxiliary device
> + * @num: IRQ number index
> + *
> + * Gets an IRQ for a auxiliary device. Device drivers should check the return value
> + * for errors so as to not pass a negative integer value to the request_irq()
> + * APIs. This is the same as auxiliary_get_irq(), except that it does not print an
> + * error message if an IRQ can not be obtained.
> + *
> + * For example::
> + *
> + *		int irq = auxiliary_get_irq_optional(auxdev, 0);
> + *		if (irq < 0)
> + *			return irq;
> + *
> + * Return: non-zero IRQ number on success, negative error number on failure.
> + */
> +int auxiliary_get_irq_optional(struct auxiliary_device *auxdev, unsigned int num)
> +{
> +	struct resource *r;
> +	int ret = -ENXIO;
> +
> +	r = auxiliary_get_resource(auxdev, IORESOURCE_IRQ, num);
> +	if (!r)
> +		goto out;
> +
> +	/*
> +	 * The resources may pass trigger flags to the irqs that need to be
> +	 * set up. It so happens that the trigger flags for IORESOURCE_BITS
> +	 * correspond 1-to-1 to the IRQF_TRIGGER* settings.
> +	 */
> +	if (r->flags & IORESOURCE_BITS) {
> +		struct irq_data *irqd;
> +
> +		irqd = irq_get_irq_data(r->start);
> +		if (!irqd)
> +			goto out;
> +		irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
> +	}
> +
> +	ret = r->start;
> +	if (WARN(!ret, "0 is an invalid IRQ number\n"))
> +		ret = -EINVAL;
> +out:
> +	return ret;
> +}

Please, do not inherit the issues that the respective platform device API has.
And after all, why do you need this? What's wrong with plain fwnode_irq_get()?

-- 
With Best Regards,
Andy Shevchenko