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authorMarc Zyngier <marc.zyngier@arm.com>2011-09-23 17:03:06 +0100
committerThomas Gleixner <tglx@linutronix.de>2011-10-03 15:35:26 +0200
commit31d9d9b6d83030f748d013e61502fa5477e2ac0e (patch)
tree503670b94d594c09daa83c047b426e7b5328aa76 /kernel/irq/irqdesc.c
parent60f96b41f71d2a13d1c0a457b8b77958f77142d1 (diff)
downloadlinux-31d9d9b6d83030f748d013e61502fa5477e2ac0e.tar.gz
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>
Diffstat (limited to 'kernel/irq/irqdesc.c')
-rw-r--r--kernel/irq/irqdesc.c32
1 files changed, 31 insertions, 1 deletions
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 039b889ea053..1550e8447a16 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -424,11 +424,22 @@ unsigned int irq_get_next_irq(unsigned int offset)
}
struct irq_desc *
-__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus)
+__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
+ unsigned int check)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc) {
+ if (check & _IRQ_DESC_CHECK) {
+ if ((check & _IRQ_DESC_PERCPU) &&
+ !irq_settings_is_per_cpu_devid(desc))
+ return NULL;
+
+ if (!(check & _IRQ_DESC_PERCPU) &&
+ irq_settings_is_per_cpu_devid(desc))
+ return NULL;
+ }
+
if (bus)
chip_bus_lock(desc);
raw_spin_lock_irqsave(&desc->lock, *flags);
@@ -443,6 +454,25 @@ void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
chip_bus_sync_unlock(desc);
}
+int irq_set_percpu_devid(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (!desc)
+ return -EINVAL;
+
+ if (desc->percpu_enabled)
+ return -EINVAL;
+
+ desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);
+
+ if (!desc->percpu_enabled)
+ return -ENOMEM;
+
+ irq_set_percpu_devid_flags(irq);
+ return 0;
+}
+
/**
* dynamic_irq_cleanup - cleanup a dynamically allocated irq
* @irq: irq number to initialize