183 lines
5.3 KiB
Groff
183 lines
5.3 KiB
Groff
.\" -*- nroff -*-
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.\"
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.\" Copyright (c) 2000 Alexander Langer
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.\"
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.\" All rights reserved.
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.\"
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.\" This program is free software.
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 DEVELOPERS 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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.\" $FreeBSD$
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.\"
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.Dd May 18, 2000
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.Dt BUS_ALLOC_RESOURCE 9
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.Os
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.Sh NAME
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.Nm bus_alloc_resource ,
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.Nm bus_alloc_resource_any
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.Nd allocate resources from a parent bus
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/bus.h
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.Pp
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.In machine/bus.h
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.In sys/rman.h
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.In machine/resource.h
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.Ft struct resource *
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.Fn bus_alloc_resource "device_t dev" "int type" "int *rid" "u_long start" "u_long end" "u_long count" "u_int flags"
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.Ft struct resource *
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.Fn bus_alloc_resource_any "device_t dev" "int type" "int *rid" "u_int flags"
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.Sh DESCRIPTION
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This is an easy interface to the resource-management functions.
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It hides the indirection through the parent's method table.
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This function generally should be called in attach, but (except in some
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rare cases) never earlier.
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.Pp
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The
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.Fn bus_alloc_resource_any
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function is a convenience wrapper for
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.Fn bus_alloc_resource .
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It sets the values for
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.Fa start ,
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.Fa end ,
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and
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.Fa count
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to the default resource (see description of
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.Fa start
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below).
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.Pp
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The arguments are as follows:
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.Bl -item
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.It
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.Fa dev
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is the device that requests ownership of the resource.
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Before allocation, the resource is owned by the parent bus.
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.It
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.Fa type
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is the type of resource you want to allocate.
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It is one of:
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.Bl -tag -width SYS_RES_MEMORY
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.It Dv SYS_RES_IRQ
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for IRQs
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.It Dv SYS_RES_DRQ
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for ISA DMA lines
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.It Dv SYS_RES_IOPORT
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for I/O ports
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.It Dv SYS_RES_MEMORY
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for I/O memory
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.El
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.It
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.Fa rid
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points to a bus specific handle that identifies the resource being allocated.
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For ISA this is an index into an array of resources that have been setup
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for this device by either the PnP mechanism, or via the hints mechanism.
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For PCCARD, similar things are used as of writing,
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but that may change in the future with newcard.
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For PCI it just happens to be the offset into pci config space which has
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a word that describes the resource.
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The bus methods are free to change the RIDs that they are given as a parameter.
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You must not depend on the value you gave it earlier.
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.It
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.Fa start
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and
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.Fa end
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are the start/end addresses of the resource.
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If you specify values of 0ul for
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.Fa start
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and ~0ul for
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.Fa end
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and 1 for
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.Fa count ,
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the default values for the bus are calculated.
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.It
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.Fa count
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is the size of the resource.
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For example, the size of an I/O port is usually 1 byte (but some devices
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override this).
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If you specified the default values for
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.Fa start
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and
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.Fa end ,
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then the default value of the bus is used if
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.Fa count
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is smaller than the default value and
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.Fa count
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is used, if it is bigger than the default value.
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.It
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.Fa flags
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sets the flags for the resource.
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You can set one or more of these flags:
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.Bl -tag -width RF_SHAREABLE
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.It Dv RF_ALLOCATED
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resource has been reserved.
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The resource still needs to be activated with
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.Xr bus_activate_resource 9 .
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.It Dv RF_ACTIVE
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activate resource atomically.
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.It Dv RF_SHAREABLE
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resource permits contemporaneous sharing.
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It should always be set unless you know that the resource cannot be shared.
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It is the bus driver's task to filter out the flag if the bus does not
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support sharing.
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For example,
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.Xr pccard 4
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cannot share IRQs while
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.Xr cardbus 4
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can.
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.It Dv RF_TIMESHARE
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resource permits time-division sharing.
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.El
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.El
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.Sh RETURN VALUES
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A pointer to
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.Va struct resource
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is returned on success, a null pointer otherwise.
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.Sh EXAMPLES
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This is some example code that allocates a 32 byte I/O port range and an IRQ.
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The values of
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.Va portid
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and
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.Va irqid
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should be saved in the softc of the device after these calls.
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.Bd -literal
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struct resource *portres, irqres;
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int portid, irqid;
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portid = 0;
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irqid = 0;
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portres = bus_alloc_resource(dev, SYS_RES_IOPORT, &portid,
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0ul, ~0ul, 32, RF_ACTIVE);
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irqres = bus_alloc_resource_any(dev, SYS_RES_IRQ, &irqid,
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RF_ACTIVE | RF_SHAREABLE);
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.Ed
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.Sh SEE ALSO
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.Xr bus_activate_resource 9 ,
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.Xr bus_release_resource 9 ,
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.Xr device 9 ,
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.Xr driver 9
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.Sh AUTHORS
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.An -nosplit
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This man page was written by
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.An Alexander Langer Aq alex@big.endian.de
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with parts by
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.An Warner Losh Aq imp@FreeBSD.org .
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