147 lines
4.4 KiB
Groff
147 lines
4.4 KiB
Groff
.\" -*- nroff -*-
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.\"
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.\" Copyright (c) 2003 M. Warner Losh <imp@FreeBSD.org>
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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 20, 2016
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.Dt BUS_ACTIVATE_RESOURCE 9
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.Os
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.Sh NAME
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.Nm bus_activate_resource , bus_deactivate_resource
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.Nd activate or deactivate a resource
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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 int
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.Fo bus_activate_resource
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.Fa "device_t dev" "int type" "int rid" "struct resource *r"
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.Fc
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.Ft int
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.Fo bus_deactivate_resource
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.Fa "device_t dev" "int type" "int rid" "struct resource *r"
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.Fc
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.Sh DESCRIPTION
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These functions activate or deactivate a previously allocated resource.
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In general, resources must be activated before they can be accessed by
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the driver.
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Bus drivers may perform additional actions to ensure that the resource is
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ready to be accessed.
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For example,
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the PCI bus driver enables memory decoding in a PCI device's command register
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when activating a memory resource.
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.Pp
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The arguments are as follows:
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.Bl -tag -width indent
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.It Fa dev
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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 Fa type
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The type of resource you want to allocate.
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It is one of:
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.Pp
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.Bl -tag -width ".Dv SYS_RES_MEMORY" -compact
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.It Dv PCI_RES_BUS
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for PCI bus numbers
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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 Fa rid
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A pointer to a bus specific handle that identifies the resource being allocated.
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.It Fa r
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A pointer to the
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.Vt "struct resource"
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returned by
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.Xr bus_alloc_resource 9 .
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.El
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.Ss Resource Mapping
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Resources which can be mapped for CPU access by a
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.Xr bus_space 9
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tag and handle will create a mapping of the entire resource when activated.
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The tag and handle for this mapping are stored in
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.Fa r
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and can be retrieved via
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.Xr rman_get_bustag 9
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and
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.Xr rman_get_bushandle 9 .
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These can be used with the
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.Xr bus_space 9
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API to access device registers or memory described by
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.Fa r .
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If the mapping is associated with a virtual address,
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the virtual address can be retrieved via
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.Xr rman_get_virtual 9 .
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.Pp
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This implicit mapping can be disabled by passing the
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.Dv RF_UNMAPPED
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flag to
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.Xr bus_alloc_resource 9 .
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A driver may use this if it wishes to allocate its own mappings of a resource
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using
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.Xr bus_map_resource 9 .
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.Pp
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A wrapper API for
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.Xr bus_space 9
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is also provided that accepts the associated resource as the first argument
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in place of the
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.Xr bus_space 9
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tag and handle.
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The functions in this wrapper API are named similarly to the
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.Xr bus_space 9
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API except that
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.Dq _space
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is removed from their name.
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For example,
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.Fn bus_read_4
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can be used in place of
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.Fn bus_space_read_4 .
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The wrapper API is preferred in new drivers.
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.Pp
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These two statements both read a 32-bit register at the start of a
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resource:
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.Bd -literal
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bus_space_read_4(rman_get_bustag(res), rman_get_bushandle(res), 0);
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bus_read_4(res, 0);
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.Ed
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.Sh RETURN VALUES
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Zero is returned on success, otherwise an error is returned.
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.Sh SEE ALSO
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.Xr bus_alloc_resource 9 ,
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.Xr bus_map_resource 9 ,
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.Xr bus_space 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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This manual page was written by
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.An Warner Losh Aq Mt imp@FreeBSD.org .
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