linux/kernel/irq
Marc Zyngier 31d9d9b6d8 genirq: Add support for per-cpu dev_id interrupts
The ARM GIC interrupt controller offers per CPU interrupts (PPIs),
which are usually used to connect local timers to each core. Each CPU
has its own private interface to the GIC, and only sees the PPIs that
are directly connect to it.

While these timers are separate devices and have a separate interrupt
line to a core, they all use the same IRQ number.

For these devices, request_irq() is not the right API as it assumes
that an IRQ number is visible by a number of CPUs (through the
affinity setting), but makes it very awkward to express that an IRQ
number can be handled by all CPUs, and yet be a different interrupt
line on each CPU, requiring a different dev_id cookie to be passed
back to the handler.

The *_percpu_irq() functions is designed to overcome these
limitations, by providing a per-cpu dev_id vector:

int request_percpu_irq(unsigned int irq, irq_handler_t handler,
		   const char *devname, void __percpu *percpu_dev_id);
void free_percpu_irq(unsigned int, void __percpu *);
int setup_percpu_irq(unsigned int irq, struct irqaction *new);
void remove_percpu_irq(unsigned int irq, struct irqaction *act);
void enable_percpu_irq(unsigned int irq);
void disable_percpu_irq(unsigned int irq);

The API has a number of limitations:
- no interrupt sharing
- no threading
- common handler across all the CPUs

Once the interrupt is requested using setup_percpu_irq() or
request_percpu_irq(), it must be enabled by each core that wishes its
local interrupt to be delivered.

Based on an initial patch by Thomas Gleixner.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1316793788-14500-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-10-03 15:35:26 +02:00
..
autoprobe.c genirq: Remove compat code 2011-03-29 14:48:19 +02:00
chip.c genirq: Add support for per-cpu dev_id interrupts 2011-10-03 15:35:26 +02:00
debug.h genirq: Support per-IRQ thread disabling. 2011-04-23 15:56:24 +02:00
devres.c devres: fix possible use after free 2011-07-25 20:57:14 -07:00
dummychip.c genirq: Remove compat code 2011-03-29 14:48:19 +02:00
generic-chip.c genirq: Fix wrong bit operation 2011-07-26 16:24:02 +02:00
handle.c irq: Handle spurios irq detection for threaded irqs 2011-06-03 14:53:15 +02:00
internals.h genirq: Add support for per-cpu dev_id interrupts 2011-10-03 15:35:26 +02:00
irqdesc.c genirq: Add support for per-cpu dev_id interrupts 2011-10-03 15:35:26 +02:00
irqdomain.c dt/irq: add irq_domain_generate_simple() helper 2011-07-28 01:32:04 -06:00
Kconfig irq: add irq_domain translation infrastructure 2011-07-28 01:32:04 -06:00
Makefile irq: add irq_domain translation infrastructure 2011-07-28 01:32:04 -06:00
manage.c genirq: Add support for per-cpu dev_id interrupts 2011-10-03 15:35:26 +02:00
migration.c Fix common misspellings 2011-03-31 11:26:23 -03:00
pm.c genirq: Add chip flag to force mask on suspend 2011-03-12 11:12:58 +01:00
proc.c irq: Remove smp_affinity_list when unregister irq proc 2011-05-26 13:15:28 +02:00
resend.c genirq: Remove compat code 2011-03-29 14:48:19 +02:00
settings.h genirq: Add support for per-cpu dev_id interrupts 2011-10-03 15:35:26 +02:00
spurious.c irq: Handle spurios irq detection for threaded irqs 2011-06-03 14:53:15 +02:00