.\" Copyright (c) 2000 Jeroen Ruigrok van der Werven
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.Dd March 1, 2007
.Dt BUS_SETUP_INTR 9
.Os
.Sh NAME
.Nm BUS_SETUP_INTR ,
.Nm bus_setup_intr ,
.Nm BUS_TEARDOWN_INTR ,
.Nm bus_teardown_intr
.Nd create, attach and teardown an interrupt handler
.Sh SYNOPSIS
.In sys/param.h
.In sys/bus.h
.Ft int
.Fo BUS_SETUP_INTR
.Fa "device_t dev" "device_t child" "struct resource *irq" "int flags"
.Fa "driver_filter_t *filter" "driver_intr_t *ithread" "void *arg"
.Fa "void **cookiep"
.Fc
.Ft int
.Fo bus_setup_intr
.Fa "device_t dev" "struct resource *r" "int flags"
.Fa "driver_filter_t filter" "driver_intr_t ithread" "void *arg"
.Fa "void **cookiep"
.Fc
.Ft int
.Fo BUS_TEARDOWN_INTR
.Fa "device_t dev" "device_t child" "struct resource *irq" "void *cookiep"
.Fc
.Ft int
.Fn bus_teardown_intr "device_t dev" "struct resource *r" "void *cookiep"
.Sh DESCRIPTION
The
.Fn BUS_SETUP_INTR
method
will create and attach an interrupt handler to an interrupt
previously allocated by the resource manager's
.Xr BUS_ALLOC_RESOURCE 9
method.
The
.Fa flags
are found in
.In sys/bus.h ,
and give the broad category of interrupt.
The
.Fa flags
also tell the interrupt handlers about certain
device driver characteristics.
.Dv INTR_EXCL
marks the handler as being
an exclusive handler for this interrupt.
.Dv INTR_MPSAFE
tells the scheduler that the interrupt handler
is well behaved in a preemptive environment
(``SMP safe''),
and does not need
to be protected by the ``Giant Lock'' mutex.
.Dv INTR_ENTROPY
marks the interrupt as being a good source of entropy -
this may be used by the entropy device
.Pa /dev/random .
.Pp
To define a time-critical handler (previously known as
.Dv INTR_FAST )
that will not execute any potentially blocking operation, use the
.Fa filter
argument.
Otherwise, use the
.Fa ithread
argument.
The defined handler
will be called with the value
.Fa arg
as its only argument.
.Pp
The
.Fa cookiep
argument is a pointer to a
.Vt "void *"
that
.Fn BUS_SETUP_INTR
will write a cookie for the parent bus' use to if it is successful in
establishing an interrupt.
Driver writers may assume that this cookie will be non-zero.
The nexus driver will write 0 on failure to
.Fa cookiep .
.Pp
The interrupt handler will be detached by
.Fn BUS_TEARDOWN_INTR .
The cookie needs to be passed to
.Fn BUS_TEARDOWN_INTR
in order to tear down the correct interrupt handler.
Once
.Fn BUS_TEARDOWN_INTR
returns, it is guaranteed that the interrupt function is not active and
will no longer be called.
.Pp
Mutexes are not allowed to be held across calls to these functions.
.Sh RETURN VALUES
Zero is returned on success,
otherwise an appropriate error is returned.
.Sh SEE ALSO
.Xr random 4 ,
.Xr device 9 ,
.Xr driver 9
.Sh AUTHORS
.An -nosplit
This manual page was written by
.An Jeroen Ruigrok van der Werven
.Aq asmodai@FreeBSD.org
based on the manual pages for
.Fn BUS_CREATE_INTR
and
.Fn BUS_CONNECT_INTR
written by
.An Doug Rabson
.Aq dfr@FreeBSD.org .