You would hope that if you have a GICv3 in your system, you'd use the ITS,
as it provides a large interrupt ID space and device isolation. Sadly,
some SoC integrations are less than perfect, and the ITS is not usesable on
those.
The only solution for these systems is to use the MBI interface, and
rely on a very small number of possible vectors.
This patch thus adds minimal support for PCI/MSI on top of the GICv3
MBI driver. Please don't use it if you can avoid it.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-9-marc.zyngier@arm.com
GICv3 offers the possibility to signal SPIs using a pair of doorbells
(SETPI, CLRSPI) under the name of Message Based Interrupts (MBI).
They can be used as either traditional (edge) MSIs, or the more exotic
level-triggered flavour.
Let's implement support for platform MSI, which is the original intent
for this feature.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-8-marc.zyngier@arm.com
