Re: [PATCH v6 06/11] devm-helpers: Add resource managed version of irq_create_mapping()

[Matti Vaittinen <mazziesaccount@gmail.com>]

On 4/18/24 15:11, Marek Behún wrote:
> Add resource managed version of irq_create_mapping(), to help drivers
> automatically dispose a linux irq mapping when driver is detached.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>
> ---
>   include/linux/devm-helpers.h | 54 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 54 insertions(+)
> 
> diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h
> index 74891802200d..fe62b28baf03 100644
> --- a/include/linux/devm-helpers.h
> +++ b/include/linux/devm-helpers.h
> @@ -24,6 +24,8 @@
>    */
>   
>   #include <linux/device.h>
> +#include <linux/kconfig.h>
> +#include <linux/irqdomain.h>

I still think stuffing all unrelated APIs in one header will lead to 
problems because of the sheer amount of unrelated stuff which gets 
included when only some APIs from this file are used.

But as I said during V5 review, I don't want to block this if no one 
else thinks it is a real problem.

Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>

>   #include <linux/workqueue.h>
>   
>   static inline void devm_delayed_work_drop(void *res)
> @@ -76,4 +78,56 @@ static inline int devm_work_autocancel(struct device *dev,
>   	return devm_add_action(dev, devm_work_drop, w);
>   }
>   
> +/**
> + * devm_irq_mapping_drop - devm action for disposing an irq mapping
> + * @res:	linux irq number cast to the void * type
> + *
> + * devm_irq_mapping_drop() can be used as an action parameter for the
> + * devm_add_action_or_reset() function in order to automatically dispose
> + * a linux irq mapping when a device driver is detached.
> + */
> +static inline void devm_irq_mapping_drop(void *res)
> +{
> +	irq_dispose_mapping((unsigned int)(unsigned long)res);
> +}
> +
> +/**
> + * devm_irq_create_mapping - Resource managed version of irq_create_mapping()
> + * @dev:	Device which lifetime the mapping is bound to
> + * @domain:	domain owning this hardware interrupt or NULL for default domain
> + * @hwirq:	hardware irq number in that domain space
> + *
> + * Create an irq mapping to linux irq space which is automatically disposed when
> + * the driver is detached.
> + * devm_irq_create_mapping() can be used to omit the explicit
> + * irq_dispose_mapping() call when driver is detached.
> + *
> + * Returns a linux irq number on success, -ENXIO if the mapping could not be
> + * created, or a negative error number if devm action could not be added.
> + */
> +static inline int devm_irq_create_mapping(struct device *dev,
> +					  struct irq_domain *domain,
> +					  irq_hw_number_t hwirq)
> +{
> +	unsigned int virq = irq_create_mapping(domain, hwirq);
> +
> +	if (!virq)
> +		return -ENXIO;
> +
> +	/*
> +	 * irq_dispose_mapping() is an empty function if CONFIG_IRQ_DOMAIN is
> +	 * disabled. No need to register an action in that case.
> +	 */
> +	if (IS_ENABLED(CONFIG_IRQ_DOMAIN)) {
> +		int err;
> +
> +		err = devm_add_action_or_reset(dev, devm_irq_mapping_drop,
> +					       (void *)(unsigned long)virq);
> +		if (err)
> +			return err;
> +	}
> +
> +	return virq;
> +}
> +
>   #endif

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~