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>
This commit is contained in:
Jiri Kosina 2013-03-21 00:21:21 +01:00 committed by Greg Kroah-Hartman
parent 4c6e22b8a9
commit 54f69b92f0
3 changed files with 68 additions and 0 deletions

View file

@ -93,6 +93,14 @@ config ATMEL_TCB_CLKSRC_BLOCK
TC can be used for other purposes, such as PWM generation and TC can be used for other purposes, such as PWM generation and
interval timing. interval timing.
config DUMMY_IRQ
tristate "Dummy IRQ handler"
default n
---help---
This module accepts a single 'irq' parameter, which it should register for.
The sole purpose of this module is to help with debugging of systems on
which spurious IRQs would happen on disabled IRQ vector.
config IBM_ASM config IBM_ASM
tristate "Device driver for IBM RSA service processor" tristate "Device driver for IBM RSA service processor"
depends on X86 && PCI && INPUT depends on X86 && PCI && INPUT

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@ -13,6 +13,7 @@ obj-$(CONFIG_ATMEL_TCLIB) += atmel_tclib.o
obj-$(CONFIG_BMP085) += bmp085.o obj-$(CONFIG_BMP085) += bmp085.o
obj-$(CONFIG_BMP085_I2C) += bmp085-i2c.o obj-$(CONFIG_BMP085_I2C) += bmp085-i2c.o
obj-$(CONFIG_BMP085_SPI) += bmp085-spi.o obj-$(CONFIG_BMP085_SPI) += bmp085-spi.o
obj-$(CONFIG_DUMMY_IRQ) += dummy-irq.o
obj-$(CONFIG_ICS932S401) += ics932s401.o obj-$(CONFIG_ICS932S401) += ics932s401.o
obj-$(CONFIG_LKDTM) += lkdtm.o obj-$(CONFIG_LKDTM) += lkdtm.o
obj-$(CONFIG_TIFM_CORE) += tifm_core.o obj-$(CONFIG_TIFM_CORE) += tifm_core.o

59
drivers/misc/dummy-irq.c Normal file
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@ -0,0 +1,59 @@
/*
* 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");