From 9e2c986cb460bf97154f18e85aa833739a1e8dc7 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 11 Apr 2016 09:57:53 +0100 Subject: 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 Cc: Mark Rutland Cc: devicetree@vger.kernel.org Cc: Jason Cooper Cc: Will Deacon Cc: Rob Herring Link: http://lkml.kernel.org/r/1460365075-7316-4-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner --- drivers/irqchip/Makefile | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/irqchip/Makefile') diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index b03cfcbbac6b..e354b00c173d 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_REALVIEW_DT) += irq-gic-realview.o obj-$(CONFIG_ARM_GIC_V2M) += irq-gic-v2m.o obj-$(CONFIG_ARM_GIC_V3) += irq-gic-v3.o irq-gic-common.o obj-$(CONFIG_ARM_GIC_V3_ITS) += irq-gic-v3-its.o irq-gic-v3-its-pci-msi.o irq-gic-v3-its-platform-msi.o +obj-$(CONFIG_PARTITION_PERCPU) += irq-partition-percpu.o obj-$(CONFIG_HISILICON_IRQ_MBIGEN) += irq-mbigen.o obj-$(CONFIG_ARM_NVIC) += irq-nvic.o obj-$(CONFIG_ARM_VIC) += irq-vic.o -- cgit v1.2.3