PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 95 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-rpmsg b/Documentation/ABI/testing/sysfs-bus-rpmsg
new file mode 100644
index 000000000..990fcc420
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-rpmsg
@@ -0,0 +1,95 @@
+What:		/sys/bus/rpmsg/devices/.../name
+Date:		June 2011
+KernelVersion:	3.3
+Contact:	Ohad Ben-Cohen <ohad@wizery.com>
+Description:
+		Every rpmsg device is a communication channel with a remote
+		processor. Channels are identified with a (textual) name,
+		which is maximum 32 bytes long (defined as RPMSG_NAME_SIZE in
+		rpmsg.h).
+
+		This sysfs entry contains the name of this channel.
+
+What:		/sys/bus/rpmsg/devices/.../src
+Date:		June 2011
+KernelVersion:	3.3
+Contact:	Ohad Ben-Cohen <ohad@wizery.com>
+Description:
+		Every rpmsg device is a communication channel with a remote
+		processor. Channels have a local ("source") rpmsg address,
+		and remote ("destination") rpmsg address. When an entity
+		starts listening on one end of a channel, it assigns it with
+		a unique rpmsg address (a 32 bits integer). This way when
+		inbound messages arrive to this address, the rpmsg core
+		dispatches them to the listening entity (a kernel driver).
+
+		This sysfs entry contains the src (local) rpmsg address
+		of this channel. If it contains 0xffffffff, then an address
+		wasn't assigned (can happen if no driver exists for this
+		channel).
+
+What:		/sys/bus/rpmsg/devices/.../dst
+Date:		June 2011
+KernelVersion:	3.3
+Contact:	Ohad Ben-Cohen <ohad@wizery.com>
+Description:
+		Every rpmsg device is a communication channel with a remote
+		processor. Channels have a local ("source") rpmsg address,
+		and remote ("destination") rpmsg address. When an entity
+		starts listening on one end of a channel, it assigns it with
+		a unique rpmsg address (a 32 bits integer). This way when
+		inbound messages arrive to this address, the rpmsg core
+		dispatches them to the listening entity.
+
+		This sysfs entry contains the dst (remote) rpmsg address
+		of this channel. If it contains 0xffffffff, then an address
+		wasn't assigned (can happen if the kernel driver that
+		is attached to this channel is exposing a service to the
+		remote processor. This make it a local rpmsg server,
+		and it is listening for inbound messages that may be sent
+		from any remote rpmsg client; it is not bound to a single
+		remote entity).
+
+What:		/sys/bus/rpmsg/devices/.../announce
+Date:		June 2011
+KernelVersion:	3.3
+Contact:	Ohad Ben-Cohen <ohad@wizery.com>
+Description:
+		Every rpmsg device is a communication channel with a remote
+		processor. Channels are identified by a textual name (see
+		/sys/bus/rpmsg/devices/.../name above) and have a local
+		("source") rpmsg address, and remote ("destination") rpmsg
+		address.
+
+		A channel is first created when an entity, whether local
+		or remote, starts listening on it for messages (and is thus
+		called an rpmsg server).
+
+		When that happens, a "name service" announcement is sent
+		to the other processor, in order to let it know about the
+		creation of the channel (this way remote clients know they
+		can start sending messages).
+
+		This sysfs entry tells us whether the channel is a local
+		server channel that is announced (values are either
+		true or false).
+
+What:		/sys/bus/rpmsg/devices/.../driver_override
+Date:		April 2018
+KernelVersion:	4.18
+Contact:	Bjorn Andersson <bjorn.andersson@linaro.org>
+Description:
+		Every rpmsg device is a communication channel with a remote
+		processor. Channels are identified by a textual name (see
+		/sys/bus/rpmsg/devices/.../name above) and have a local
+		("source") rpmsg address, and remote ("destination") rpmsg
+		address.
+
+		The listening entity (or client) which communicates with a
+		remote processor is referred as rpmsg driver. The rpmsg device
+		and rpmsg driver are matched based on rpmsg device name and
+		rpmsg driver ID table.
+
+		This sysfs entry allows the rpmsg driver for a rpmsg device
+		to be specified which will override standard OF, ID table
+		and name matching.