142 lines
4.9 KiB
Groff
142 lines
4.9 KiB
Groff
.\" $NetBSD: softintr.9,v 1.5 2001/01/21 00:50:48 augustss Exp $
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.\"
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.\" Copyright (c) 2000 Christopher G. Demetriou.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed for the
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.\" NetBSD Project. See http://www.netbsd.org/ for
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.\" information about NetBSD.
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.\" 4. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" --(license Id: LICENSE.proto,v 1.1 2000/06/13 21:40:26 cgd Exp )--
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.\"
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.Dd May 30, 2000
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.Dt SOFTINTR 9
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.Os
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.Sh NAME
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.Nm softintr ,
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.Nm softintr_establish ,
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.Nm softintr_disestablish ,
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.Nm softintr_schedule
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.Nd machine-independent software interrupt framework
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.Sh SYNOPSIS
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.Fd #include <machine/intr.h>
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.Ft void *
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.Fn softintr_establish "int level" "void (*fun)(void *)" "void *arg"
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.Ft void
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.Fn softintr_disestablish "void *cookie"
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.Ft void
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.Fn softintr_schedule "void *cookie"
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.Sh DESCRIPTION
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The
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.Nx
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machine-independent software interrupt framework is designed to provide
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a generic software interrupt mechanism which can be used any time a
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low-priority callback is needed. It allows dynamic registration of
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software interrupts for loadable drivers and protocol stacks,
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prioritization and fair queueing of software interrupts, and
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allows machine-dependent optimizations to reduce cost and code
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complexity.
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.Pp
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In order to provide this framework, the machine-dependent
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.Aq Pa machine/types.h
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must define the
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.Dv __HAVE_GENERIC_SOFT_INTERRUPTS
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symbol (without a value),
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furthermore, the machine-dependent
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.Aq Pa machine/intr.h
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include file must provide prototypes for the
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.Nm
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functions and must provide definitions of
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several constants which define software interrupt priority levels
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(IPLs):
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.Bl -tag -width "IPL_SOFTSERIAL"
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.It Dv IPL_SOFTCLOCK
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The software IPL for software clock interrupts
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.Pq i.e., Fn softclock .
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.It Dv IPL_SOFTNET
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The software IPL for network callbacks.
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.It Dv IPL_SOFTSERIAL
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The software IPL for serial driver callbacks.
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.El
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.Pp
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Other constants of the form
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.Dv IPL_SOFT*
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are reserved for future use by this framework.
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.Pp
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The following is a brief description of each function in the framework:
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.Bl -tag -width "softintr_disestablish()"
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.It Fn softintr_establish
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Register a software interrupt at level
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.Fa level ,
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which will call the function
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.Fa fun
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with one
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argument,
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.Fa arg .
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It may allocate a machine-specific data structure.
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If successful,
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.Fn softintr_establish
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returns a
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.Pf non- Dv NULL
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opaque cookie which can be used as an argument to
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.Fn softintr_schedule
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or
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.Fn softintr_disestablish .
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If for some reason it does not succeed, it returns
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.Dv NULL .
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.It Fn softintr_disestablish
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Deallocate a software interrupt previously allocated
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by a call to
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.Fn softintr_establish .
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.\" XXX What happens to pending scheduled calls?
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.It Fn softintr_schedule
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Schedule a software interrupt previously allocated
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by a call to
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.Fn softintr_establish
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to be executed as soon as that software interrupt is unblocked.
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This function may assume that the interrupt is currently blocked,
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so it need not check to see if the interrupt needs to be executed
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immediately.
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.Fn softintr_schedule
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can safely be called multiple times before the
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callback routine is invoked.
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.El
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.Sh AUTHOR
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The
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.Nx
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machine-independent software interrupt framework was designed by
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Charles Hannum <mycroft@NetBSD.ORG>.
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.Sh SEE ALSO
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.Xr spl 9
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.Sh HISTORY
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The
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.Nx
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machine-independent software interrupt framework was designed in 1997
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and was implemented by one port in
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.Nx 1.3 .
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However, it did not gain wider implementation until
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.Nx 1.5 .
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