diff options
author | Jiri Kosina <jkosina@suse.cz> | 2013-03-21 03:21:21 +0400 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-26 00:22:32 +0400 |
commit | 54f69b92f037f4ff5779e5645ab714dee5b59095 (patch) | |
tree | cd935d3d36afbe0627a64c0774b662696c9c06d7 /drivers/misc/dummy-irq.c | |
parent | 4c6e22b8a93ef038b70661e590de250a09417af7 (diff) | |
download | linux-54f69b92f037f4ff5779e5645ab714dee5b59095.tar.xz |
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>
Diffstat (limited to 'drivers/misc/dummy-irq.c')
-rw-r--r-- | drivers/misc/dummy-irq.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/drivers/misc/dummy-irq.c b/drivers/misc/dummy-irq.c new file mode 100644 index 000000000000..7014167e2c61 --- /dev/null +++ b/drivers/misc/dummy-irq.c @@ -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"); |