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authorMarc Zyngier <maz@misterjones.org>2010-03-15 22:56:33 +0000
committerThomas Gleixner <tglx@linutronix.de>2010-04-13 16:36:39 +0200
commitae731f8d0785ccd3380f511bae888933b6562e45 (patch)
tree07db03ce79231153a4ae5df75c0ca4dcd96307c2 /kernel/irq
parent7c7145f6acc68100dbdc5d3c5c64fe3af1c99c89 (diff)
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/irq')
-rw-r--r--kernel/irq/manage.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 704e488730a5..84f32278ff1f 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);