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Commit f8b5473f authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Russell King
Browse files

[ARM] 3690/1: genirq: Introduce and make use of dummy irq chip 



Patch from Thomas Gleixner

From: Thomas Gleixner <tglx@linutronix.de>

ARM has a couple of really dumb interrupt controllers.
Implement a generic one and fixup the ARM migration. ARM reused
the no_irq_chip for this purpose, but this does not work out
for platforms which are not converted to the new interrupt
type handling model.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a2166abd

include/linux/irq.h

+2 −1
Original line number Diff line number Diff line
@@ -348,8 +348,9 @@ extern int noirqdebug_setup(char *str); 
/* Checks whether the interrupt can be requested by request_irq(): */

extern int can_request_irq(unsigned int irq, unsigned long irqflags);



/* Dummy irq-chip implementation: */

/* Dummy irq-chip implementations: */

extern struct irq_chip no_irq_chip;

extern struct irq_chip dummy_irq_chip;



extern void

set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,

kernel/irq/chip.c

+12 −3
Original line number Diff line number Diff line
@@ -462,9 +462,18 @@ __set_irq_handler(unsigned int irq, 
	if (!handle)

		handle = handle_bad_irq;



	if (is_chained && desc->chip == &no_irq_chip)

		printk(KERN_WARNING "Trying to install "

		       "chained interrupt type for IRQ%d\n", irq);

	if (desc->chip == &no_irq_chip) {

		printk(KERN_WARNING "Trying to install %sinterrupt handler "

		       "for IRQ%d\n", is_chained ? "chained " : " ", irq);

		/*

		 * Some ARM implementations install a handler for really dumb

		 * interrupt hardware without setting an irq_chip. This worked

		 * with the ARM no_irq_chip but the check in setup_irq would

		 * prevent us to setup the interrupt at all. Switch it to

		 * dummy_irq_chip for easy transition.

		 */

		desc->chip = &dummy_irq_chip;

	}



	spin_lock_irqsave(&desc->lock, flags);

kernel/irq/handle.c

+16 −0
Original line number Diff line number Diff line
@@ -95,6 +95,22 @@ struct irq_chip no_irq_chip = { 
	.end		= noop,

};



/*

 * Generic dummy implementation which can be used for

 * real dumb interrupt sources

 */

struct irq_chip dummy_irq_chip = {

	.name		= "dummy",

	.startup	= noop_ret,

	.shutdown	= noop,

	.enable		= noop,

	.disable	= noop,

	.ack		= noop,

	.mask		= noop,

	.unmask		= noop,

	.end		= noop,

};



/*

 * Special, empty irq handler:

 */