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author | Marc Zyngier <marc.zyngier@arm.com> | 2016-04-11 09:57:53 +0100 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2016-05-02 13:42:51 +0200 |
commit | 9e2c986cb460bf97154f18e85aa833739a1e8dc7 (patch) | |
tree | e99c9e595296ef212031e1ef1498458aee8711a3 /drivers/irqchip/Kconfig | |
parent | 222df54fd8b7641dcc81476f157806bb3144ee1d (diff) | |
download | linux-9e2c986cb460bf97154f18e85aa833739a1e8dc7.tar.gz linux-9e2c986cb460bf97154f18e85aa833739a1e8dc7.tar.bz2 linux-9e2c986cb460bf97154f18e85aa833739a1e8dc7.zip |
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/Kconfig | 3 |
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 |