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author | Marc Zyngier <maz@misterjones.org> | 2010-03-15 22:56:33 +0000 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2010-04-13 16:36:39 +0200 |
commit | ae731f8d0785ccd3380f511bae888933b6562e45 (patch) | |
tree | 07db03ce79231153a4ae5df75c0ca4dcd96307c2 /kernel | |
parent | 7c7145f6acc68100dbdc5d3c5c64fe3af1c99c89 (diff) | |
download | kernel_samsung_tuna-ae731f8d0785ccd3380f511bae888933b6562e45.zip kernel_samsung_tuna-ae731f8d0785ccd3380f511bae888933b6562e45.tar.gz kernel_samsung_tuna-ae731f8d0785ccd3380f511bae888933b6562e45.tar.bz2 |
genirq: Introduce request_any_context_irq()
Now that we enjoy threaded interrupts, we're starting to see irq_chip
implementations (wm831x, pca953x) that make use of threaded interrupts
for the controller, and nested interrupts for the client interrupt. It
all works very well, with one drawback:
Drivers requesting an IRQ must now know whether the handler will
run in a thread context or not, and call request_threaded_irq() or
request_irq() accordingly.
The problem is that the requesting driver sometimes doesn't know
about the nature of the interrupt, specially when the interrupt
controller is a discrete chip (typically a GPIO expander connected
over I2C) that can be connected to a wide variety of otherwise perfectly
supported hardware.
This patch introduces the request_any_context_irq() function that mostly
mimics the usual request_irq(), except that it checks whether the irq
level is configured as nested or not, and calls the right backend.
On success, it also returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
[ tglx: Made return value an enum, simplified code and made the export
of request_any_context_irq GPL ]
Signed-off-by: Marc Zyngier <maz@misterjones.org>
Cc: <joachim.eastwood@jotron.com>
LKML-Reference: <927ea285bd0c68934ddae1a47e44a9ba@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/irq/manage.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 704e488..84f3227 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1120,3 +1120,40 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler, return retval; } EXPORT_SYMBOL(request_threaded_irq); + +/** + * request_any_context_irq - allocate an interrupt line + * @irq: Interrupt line to allocate + * @handler: Function to be called when the IRQ occurs. + * Threaded handler for threaded interrupts. + * @flags: Interrupt type flags + * @name: An ascii name for the claiming device + * @dev_id: A cookie passed back to the handler function + * + * This call allocates interrupt resources and enables the + * interrupt line and IRQ handling. It selects either a + * hardirq or threaded handling method depending on the + * context. + * + * On failure, it returns a negative value. On success, + * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED. + */ +int request_any_context_irq(unsigned int irq, irq_handler_t handler, + unsigned long flags, const char *name, void *dev_id) +{ + struct irq_desc *desc = irq_to_desc(irq); + int ret; + + if (!desc) + return -EINVAL; + + if (desc->status & IRQ_NESTED_THREAD) { + ret = request_threaded_irq(irq, NULL, handler, + flags, name, dev_id); + return !ret ? IRQC_IS_NESTED : ret; + } + + ret = request_irq(irq, handler, flags, name, dev_id); + return !ret ? IRQC_IS_HARDIRQ : ret; +} +EXPORT_SYMBOL_GPL(request_any_context_irq); |