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Commit c1bacbae authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

genirq: Provide irq_request/release_resources chip callbacks 



For certain irq types, e.g. gpios, it's necessary to request resources
before starting up the irq.

This might fail so we cannot use the irq_startup() callback because we
might call the irq_set_type() callback before that which does not make
sense when the resource is not available. Calling irq_startup() before
irq_set_type() can lead to spurious interrupts which is not desired
either.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org 
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1403080857160.18573@ionos.tec.linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent fa389e22

include/linux/irq.h

+6 −0
Original line number Diff line number Diff line
@@ -303,6 +303,10 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d) 
 * @irq_pm_shutdown:	function called from core code on shutdown once per chip

 * @irq_calc_mask:	Optional function to set irq_data.mask for special cases

 * @irq_print_chip:	optional to print special chip info in show_interrupts

 * @irq_request_resources:	optional to request resources before calling

 *				any other callback related to this irq

 * @irq_release_resources:	optional to release resources acquired with

 *				irq_request_resources

 * @flags:		chip specific flags

 */

struct irq_chip {
@@ -336,6 +340,8 @@ struct irq_chip { 
	void		(*irq_calc_mask)(struct irq_data *data);



	void		(*irq_print_chip)(struct irq_data *data, struct seq_file *p);

	int		(*irq_request_resources)(struct irq_data *data);

	void		(*irq_release_resources)(struct irq_data *data);



	unsigned long	flags;

};

kernel/irq/manage.c

+27 −1
Original line number Diff line number Diff line
@@ -896,6 +896,23 @@ static void irq_setup_forced_threading(struct irqaction *new) 
	}

}



static int irq_request_resources(struct irq_desc *desc)

{

	struct irq_data *d = &desc->irq_data;

	struct irq_chip *c = d->chip;



	return c->irq_request_resources ? c->irq_request_resources(d) : 0;

}



static void irq_release_resources(struct irq_desc *desc)

{

	struct irq_data *d = &desc->irq_data;

	struct irq_chip *c = d->chip;



	if (c->irq_release_resources)

		c->irq_release_resources(d);

}



/*

 * Internal function to register an irqaction - typically used to

 * allocate special interrupts that are part of the architecture.
@@ -1091,6 +1108,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) 
	}



	if (!shared) {

		ret = irq_request_resources(desc);

		if (ret) {

			pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",

			       new->name, irq, desc->irq_data.chip->name);

			goto out_mask;

		}



		init_waitqueue_head(&desc->wait_for_threads);



		/* Setup the type (level, edge polarity) if configured: */
@@ -1261,8 +1285,10 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) 
	*action_ptr = action->next;



	/* If this was the last handler, shut down the IRQ line: */

	if (!desc->action)

	if (!desc->action) {

		irq_shutdown(desc);

		irq_release_resources(desc);

	}



#ifdef CONFIG_SMP

	/* make sure affinity_hint is cleaned up */