.\" -*- nroff -*-
.\"
.\" Copyright (c) 2009 Hudson River Trading LLC
.\" Written by: John H. Baldwin <jhb@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: head/share/man/man9/BUS_BIND_INTR.9 281887 2015-04-23 14:22:20Z jhb $
.\"
.Dd October 14, 2009
.Dt BUS_BIND_INTR 9
.Os
.Sh NAME
.Nm BUS_BIND_INTR ,
.Nm bus_bind_intr
.Nd "bind an interrupt resource to a specific CPU"
.Sh SYNOPSIS
.In sys/param.h
.In sys/bus.h
.Ft int
.Fo BUS_BIND_INTR
.Fa "device_t dev" "device_t child" "struct resource *irq" "int cpu"
.Fc
.Ft int
.Fn bus_bind_intr "device_t dev" "struct resource *irq" "int cpu"
.Sh DESCRIPTION
The
.Fn BUS_BIND_INTR
method allows an interrupt resource to be pinned to a specific CPU.
The interrupt resource must have an interrupt handler attached via
.Xr BUS_SETUP_INTR 9 .
The
.Fa cpu
parameter corresponds to the ID of a valid CPU in the system.
Binding an interrupt restricts the
.Xr cpuset 2
of any associated interrupt threads to only include the specified CPU.
It may also direct the low-level interrupt handling of the interrupt to the
specified CPU as well,
but this behavior is platform-dependent.
If the value
.Dv NOCPU
is used for
.Fa cpu ,
then the interrupt will be
.Dq unbound
which restores any associated interrupt threads back to the default cpuset.
.Pp
Non-sleepable locks such as mutexes should not be held across calls to these
functions.
.Pp
The
.Fn bus_bind_intr
function is a simple wrapper around
.Fn BUS_BIND_INTR .
.Pp
Note that currently there is no attempt made to arbitrate between
multiple bind requests for the same interrupt from either the same
device or multiple devices.
There is also no arbitration between interrupt binding requests submitted
by userland via
.Xr cpuset 2
and
.Fn BUS_BIND_INTR .
The most recent binding request is the one that will be in effect.
.Sh RETURN VALUES
Zero is returned on success, otherwise an appropriate error is returned.
.Sh SEE ALSO
.Xr cpuset 2 ,
.Xr BUS_SETUP_INTR 9 ,
.Xr device 9
.Sh HISTORY
The
.Fn BUS_BIND_INTR
method and
.Fn bus_bind_intr
functions first appeared in
.Fx 7.2 .