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authorMarc Zyngier <marc.zyngier@arm.com>2016-04-11 09:57:53 +0100
committerThomas Gleixner <tglx@linutronix.de>2016-05-02 13:42:51 +0200
commit9e2c986cb460bf97154f18e85aa833739a1e8dc7 (patch)
treee99c9e595296ef212031e1ef1498458aee8711a3 /drivers/irqchip/Kconfig
parent222df54fd8b7641dcc81476f157806bb3144ee1d (diff)
irqchip: Add per-cpu interrupt partitioning library
We've unfortunately started seeing a situation where percpu interrupts are partitioned in the system: one arbitrary set of CPUs has an interrupt connected to a type of device, while another disjoint set of CPUs has the same interrupt connected to another type of device. This makes it impossible to have a device driver requesting this interrupt using the current percpu-interrupt abstraction, as the same interrupt number is now potentially claimed by at least two drivers, and we forbid interrupt sharing on per-cpu interrupt. A solution to this is to turn things upside down. Let's assume that our system describes all the possible partitions for a given interrupt, and give each of them a unique identifier. It is then possible to create a namespace where the affinity identifier itself is a form of interrupt number. At this point, it becomes easy to implement a set of partitions as a cascaded irqchip, each affinity identifier being the HW irq. This allows us to keep a number of nice properties: - Each partition results in a separate percpu-interrupt (with a restrictied affinity), which keeps drivers happy. - Because the underlying interrupt is still per-cpu, the overhead of the indirection can be kept pretty minimal. - The core code can ignore most of that crap. For that purpose, we implement a small library that deals with some of the boilerplate code, relying on platform-specific drivers to provide a description of the affinity sets and a set of callbacks. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: devicetree@vger.kernel.org Cc: Jason Cooper <jason@lakedaemon.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Rob Herring <robh+dt@kernel.org> Link: http://lkml.kernel.org/r/1460365075-7316-4-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'drivers/irqchip/Kconfig')
-rw-r--r--drivers/irqchip/Kconfig3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 3e124793e224..ea1836b25156 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -244,3 +244,6 @@ config IRQ_MXS
config MVEBU_ODMI
bool
select GENERIC_MSI_IRQ_DOMAIN
+
+config PARTITION_PERCPU
+ bool