linux/drivers/misc/dummy-irq.c
Jiri Kosina 54f69b92f0 dummy-irq: introduce a dummy IRQ handler driver
This module accepts a single 'irq' parameter, which it should register for.

Its sole purpose is to help with debugging of IRQ sharing problems, by
force-enabling IRQ that would otherwise be disabled.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 13:22:32 -07:00

60 lines
1.4 KiB
C

/*
* Dummy IRQ handler driver.
*
* This module only registers itself as a handler that is specified to it
* by the 'irq' parameter.
*
* The sole purpose of this module is to help with debugging of systems on
* which spurious IRQs would happen on disabled IRQ vector.
*
* Copyright (C) 2013 Jiri Kosina
*/
/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
static int irq;
static irqreturn_t dummy_interrupt(int irq, void *dev_id)
{
static int count = 0;
if (count == 0) {
printk(KERN_INFO "dummy-irq: interrupt occured on IRQ %d\n",
irq);
count++;
}
return IRQ_NONE;
}
static int __init dummy_irq_init(void)
{
if (request_irq(irq, &dummy_interrupt, IRQF_SHARED, "dummy_irq", &irq)) {
printk(KERN_ERR "dummy-irq: cannot register IRQ %d\n", irq);
return -EIO;
}
printk(KERN_INFO "dummy-irq: registered for IRQ %d\n", irq);
return 0;
}
static void __exit dummy_irq_exit(void)
{
printk(KERN_INFO "dummy-irq unloaded\n");
free_irq(irq, &irq);
}
module_init(dummy_irq_init);
module_exit(dummy_irq_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jiri Kosina");
module_param(irq, uint, 0444);
MODULE_PARM_DESC(irq, "The IRQ to register for");