The GICv3 architecture provides a way to implement support for
MSI/MSI-X using a specific block called the ITS (Interrupt Translation
Service).
The ITS can be accurately described as "page tables for
interrupts". If you think this sounds scary, you're spot on. It uses a
set of opaque memory tables that are manipulated through commands
(software almost never touches the tables directly). In order to make
it slightly easier to digest, the code has been split into (mostly)
logical units.
To make things more fun, this relies on Jiang Liu's stacked domain
patch series as now merged in tip/irq/irqdomain:
- patch 1 imports the new asm-generic/msi.h file into arch/arm64
- patches 2 to 13 are the bulk of the ITS driver.
This has been tested on arm64 with an FVP model, and is based on
3.18-rc4 + tip/irq/irqdomain + a number of arm64-specific PCI
patches. The whole thing is available at:
git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git
irq/stacked-its-v2
M.
>From v1 [1]:
- rebased on top of tip/irq/irqdomain
- dropped the arm64-specific implementation of arch_setup_msi_irqs and co.
- reworked the whole ITS/MSI setup to use the new MSI/PCI split
[1]: http://lwn.net/Articles/619788/
Marc Zyngier (13):
arm64: PCI/MSI: Use asm-generic/msi.h
irqchip: GICv3: Convert to domain hierarchy
irqchip: GICv3: rework redistributor structure
irqchip: GICv3: ITS command queue
irqchip: GICv3: ITS: irqchip implementation
irqchip: GICv3: ITS: LPI allocator
irqchip: GICv3: ITS: tables allocators
irqchip: GICv3: ITS: device allocation and configuration
irqchip: GICv3: ITS: MSI support
irqchip: GICv3: ITS: DT probing and initialization
irqchip: GICv3: ITS: plug ITS init into main GICv3 code
irqchip: GICv3: ITS: enable compilation of the ITS driver
irqchip: GICv3: Binding updates for ITS
Documentation/devicetree/bindings/arm/gic-v3.txt | 39 +
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/Kbuild | 1 +
drivers/irqchip/Kconfig | 5 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-gic-v3-its.c | 1406 ++++++++++++++++++++++
drivers/irqchip/irq-gic-v3.c | 156 ++-
include/linux/irqchip/arm-gic-v3.h | 128 ++
8 files changed, 1697 insertions(+), 40 deletions(-)
create mode 100644 drivers/irqchip/irq-gic-v3-its.c
--
2.1.3
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