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Currently the lowest "real" irq number for the XICS irq controller (as
opposed to numbers reserved for IPIs and other special purposes) is
hard coded as 16 in two places - in xics_system_init() and in spapr.c.
As well as being generally bad practice, we're going to need to change this
number soon to fit in with the in-kernel XICS implementation. This patch
adds a #define for this number to avoid future breakage.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Ben Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Currently the XICS interrupt controller emulation uses a custom enum to
specify whether a given interrupt is level-sensitive or message-triggered.
This enum makes life awkward for saving the state, and isn't particularly
useful since there are only two possibilities. This patch replaces the
enum with a simple bool.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Currently, the interfaces in the pseries machine code for assignment
and setup of interrupts pass around qemu_irq objects. That was done
in an attempt not to be too closely linked to the specific XICS
interrupt controller. However interactions with the device tree setup
made that attempt rather futile, and XICS is part of the PAPR spec
anyway, so this really just meant we had to carry both the qemu_irq
pointers and the XICS irq numbers around.
This mess will just get worse when we add upcoming PCI MSI support,
since that will require tracking a bunch more interrupt. Therefore,
this patch reworks the spapr code to just use XICS irq numbers
(roughly equivalent to GSIs on x86) and only retrieve the qemu_irq
pointers from the XICS code when we need them (a trivial lookup).
This is a reworked and generalized version of an earlier spapr_pci
specific patch from Alexey Kardashevskiy.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: fix checkpath warning]
Signed-off-by: Alexander Graf <agraf@suse.de>
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The pseries "xics" interrupt controller, like most interrupt
controllers can support both message (i.e. edge sensitive) interrupts
and level sensitive interrupts, but it needs to know which are which.
When I implemented the xics emulation for qemu, the only devices we
supported were the PAPR virtual IO devices. These devices only use
message interrupts, so they were the only ones I implemented in xics.
Since then, however, we have added support for PCI devices, which use
level sensitive interrupts. It turns out the message interrupt logic
still actually works most of the time for these, but there are
circumstances where we can lost interrupts due to the incorrect
interrupt logic.
This patch, therefore, implements the correct xics level-sensitive
interrupt logic. The type of the interrupt is set when a device
allocates a new xics interrupt.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Currently the pseries machine init code builds up an array, envs, of
CPUState pointers for all the cpus in the system. This is kind of
pointless, given the generic code already has a perfectly good linked list
of the cpus.
In addition, there are a number of places which assume that the cpu's
cpu_index field is equal to its index in this array. This is true in
practice, because cpu_index values are just assigned sequentially, but
it's conceptually incorrect and may not always be true.
Therefore, this patch abolishes the envs array, and explicitly uses the
generic cpu linked list and cpu_index values throughout.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
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PAPR defines an interrupt control architecture which is logically divided
into ICS (Interrupt Control Presentation, each unit is responsible for
presenting interrupts to a particular "interrupt server", i.e. CPU) and
ICS (Interrupt Control Source, each unit responsible for one or more
hardware interrupts as numbered globally across the system). All PAPR
virtual IO devices expect to deliver interrupts via this mechanism. In
Linux, this interrupt controller system is handled by the "xics" driver.
On pSeries systems, access to the interrupt controller is virtualized via
hypercalls and RTAS methods. However, the virtualized interface is very
similar to the underlying interrupt controller hardware, and similar PICs
exist un-virtualized in some other systems.
This patch implements both the ICP and ICS sides of the PAPR interrupt
controller. For now, only the hypercall virtualized interface is provided,
however it would be relatively straightforward to graft an emulated
register interface onto the underlying interrupt logic if we want to add
a machine with a hardware ICS/ICP system in the future.
There are some limitations in this implementation: it is assumed for now
that only one instance of the ICS exists, although a full xics system can
have several, each responsible for a different group of hardware irqs.
ICP/ICS can handle both level-sensitve (LSI) and message signalled (MSI)
interrupt inputs. For now, this implementation supports only MSI
interrupts, since that is used by PAPR virtual IO devices.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
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