| Message ID | alpine.LNX.2.00.1303201728070.17295@pobox.suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 20 Mar 2013, Jiri Kosina wrote: > > I don't know of any way. In fact, I have been thinking of writing a > > test driver module, with a module parameter telling it which IRQ number > > to register for. It seems like the sort of thing that would be useful > > to have, from time to time. > > Ok, so how about this? > Daniel, is it enough to make the problem appear on your system (by > building this into the kernel and booting with dummy-irq.irq=16)? > > Thanks. > > > > > > From: Jiri Kosina <jkosina@suse.cz> > Subject: [PATCH] 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> This is just what I was thinking of. Three extremely minor suggestions... > +static irqreturn_t dummy_interrupt(int irq, void *dev_id) > +{ > + static int count = 0; > + > + if (count == 0) { > + printk("dummy-irq: interrupt occured on IRQ %d\n", irq); You probably should put a severity level here. KERN_INFO? > + 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); > + return; A return statement isn't needed here. > +} > + > +module_init(dummy_irq_init); > +module_exit(dummy_irq_exit); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Jiri Kosina"); > +module_param_named(irq, irq, uint, 0444); module_param is good enough when the parameter's name is the same as the variable's name. > +MODULE_PARM_DESC(irq, "The IRQ to register for"); Alan Stern
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index e83fdfe..db24b79 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -93,6 +93,14 @@ config ATMEL_TCB_CLKSRC_BLOCK TC can be used for other purposes, such as PWM generation and interval timing. +config DUMMY_IRQ + tristate "Dummy IRQ handler" + default n + ---help--- + 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. + config IBM_ASM tristate "Device driver for IBM RSA service processor" depends on X86 && PCI && INPUT diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index 35a1463..28ff261 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_ATMEL_TCLIB) += atmel_tclib.o obj-$(CONFIG_BMP085) += bmp085.o obj-$(CONFIG_BMP085_I2C) += bmp085-i2c.o obj-$(CONFIG_BMP085_SPI) += bmp085-spi.o +obj-$(CONFIG_DUMMY_IRQ) += dummy-irq.o obj-$(CONFIG_ICS932S401) += ics932s401.o obj-$(CONFIG_LKDTM) += lkdtm.o obj-$(CONFIG_TIFM_CORE) += tifm_core.o diff --git a/drivers/misc/dummy-irq.c b/drivers/misc/dummy-irq.c new file mode 100644 index 0000000..4fc13e0 --- /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 cause the IRQ to be disabled. + * + * 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("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); + return; +} + +module_init(dummy_irq_init); +module_exit(dummy_irq_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jiri Kosina"); +module_param_named(irq, irq, uint, 0444); +MODULE_PARM_DESC(irq, "The IRQ to register for");