mirror of
https://github.com/freebsd/freebsd-src
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037946dc9b
Not once has rman_reserve_resource_bound() ever been used. There are
though several uses of RF_ALIGNMENT. In light of this remove this
extra and leave the actually used portion in place.
This partially reverts commit 13fb665772.
Reviewed by: imp,jhb
Pull Request: https://github.com/freebsd/freebsd-src/pull/1224
472 lines
12 KiB
Groff
472 lines
12 KiB
Groff
.\"
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.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org>
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd March 13, 2024
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.Dt RMAN 9
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.Os
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.Sh NAME
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.Nm rman ,
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.Nm rman_activate_resource ,
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.Nm rman_adjust_resource ,
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.Nm rman_deactivate_resource ,
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.Nm rman_fini ,
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.Nm rman_init ,
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.Nm rman_init_from_resource ,
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.Nm rman_is_region_manager ,
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.Nm rman_manage_region ,
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.Nm rman_first_free_region ,
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.Nm rman_last_free_region ,
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.Nm rman_release_resource ,
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.Nm rman_reserve_resource ,
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.Nm rman_make_alignment_flags ,
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.Nm rman_get_start ,
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.Nm rman_get_end ,
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.Nm rman_get_device ,
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.Nm rman_get_size ,
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.Nm rman_get_flags ,
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.Nm rman_set_mapping ,
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.Nm rman_get_mapping ,
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.Nm rman_set_virtual ,
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.Nm rman_get_virtual ,
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.Nm rman_set_bustag ,
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.Nm rman_get_bustag ,
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.Nm rman_set_bushandle ,
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.Nm rman_get_bushandle ,
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.Nm rman_set_rid ,
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.Nm rman_get_rid ,
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.Nm rman_set_type ,
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.Nm rman_get_type
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.Nd resource management functions
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/rman.h
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.Ft int
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.Fn rman_activate_resource "struct resource *r"
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.Ft int
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.Fn rman_adjust_resource "struct resource *r" "rman_res_t start" "rman_res_t end"
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.Ft int
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.Fn rman_deactivate_resource "struct resource *r"
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.Ft int
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.Fn rman_fini "struct rman *rm"
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.Ft int
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.Fn rman_init "struct rman *rm"
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.Ft int
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.Fn rman_init_from_resource "struct rman *rm" "struct resource *r"
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.Ft int
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.Fn rman_is_region_manager "struct resource *r" "struct rman *rm"
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.Ft int
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.Fn rman_manage_region "struct rman *rm" "rman_res_t start" "rman_res_t end"
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.Ft int
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.Fn rman_first_free_region "struct rman *rm" "rman_res_t *start" "rman_res_t *end"
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.Ft int
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.Fn rman_last_free_region "struct rman *rm" "rman_res_t *start" "rman_res_t *end"
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.Ft int
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.Fn rman_release_resource "struct resource *r"
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.Ft "struct resource *"
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.Fo rman_reserve_resource
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.Fa "struct rman *rm" "rman_res_t start" "rman_res_t end" "rman_res_t count"
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.Fa "u_int flags" "device_t dev"
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.Fc
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.Ft uint32_t
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.Fn rman_make_alignment_flags "uint32_t size"
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.Ft rman_res_t
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.Fn rman_get_start "struct resource *r"
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.Ft rman_res_t
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.Fn rman_get_end "struct resource *r"
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.Ft "device_t"
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.Fn rman_get_device "struct resource *r"
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.Ft rman_res_t
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.Fn rman_get_size "struct resource *r"
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.Ft u_int
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.Fn rman_get_flags "struct resource *r"
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.Ft void
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.Fn rman_set_mapping "struct resource *r" "struct resource_map *map"
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.Ft void
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.Fn rman_get_mapping "struct resource *r" "struct resource_map *map"
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.Ft void
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.Fn rman_set_virtual "struct resource *r" "void *v"
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.Ft "void *"
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.Fn rman_get_virtual "struct resource *r"
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.Ft void
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.Fn rman_set_bustag "struct resource *r" "bus_space_tag_t t"
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.Ft bus_space_tag_t
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.Fn rman_get_bustag "struct resource *r"
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.Ft void
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.Fn rman_set_bushandle "struct resource *r" "bus_space_handle_t h"
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.Ft bus_space_handle_t
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.Fn rman_get_bushandle "struct resource *r"
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.Ft void
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.Fn rman_set_rid "struct resource *r" "int rid"
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.Ft int
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.Fn rman_get_rid "struct resource *r"
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.Ft void
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.Fn rman_set_type "struct resource *r" "int type"
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.Ft int
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.Fn rman_get_type "struct resource *r"
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.Sh DESCRIPTION
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The
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.Nm
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set of functions provides a flexible resource management abstraction.
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It is used extensively by the bus management code.
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It implements the abstractions of region and resource.
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A region descriptor is used to manage a region; this could be memory or
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some other form of bus space.
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.Pp
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Each region has a set of bounds.
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Within these bounds, allocated segments may reside.
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Each segment, termed a resource, has several properties which are
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represented by a 16-bit flag register, as follows.
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.Bd -literal
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#define RF_ALLOCATED 0x0001 /* resource has been reserved */
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#define RF_ACTIVE 0x0002 /* resource allocation has been activated */
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#define RF_SHAREABLE 0x0004 /* resource permits contemporaneous sharing */
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#define RF_FIRSTSHARE 0x0020 /* first in sharing list */
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#define RF_PREFETCHABLE 0x0040 /* resource is prefetchable */
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#define RF_UNMAPPED 0x0100 /* don't map resource when activating */
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.Ed
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.Pp
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Bits 15:10 of the flag register are used to represent the desired alignment
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of the resource within the region.
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.Pp
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The
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.Fn rman_init
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function initializes the region descriptor, pointed to by the
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.Fa rm
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argument, for use with the resource management functions.
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It is required that the fields
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.Va rm_type
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and
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.Va rm_descr
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of
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.Vt "struct rman"
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be set before calling
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.Fn rman_init .
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The field
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.Va rm_type
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shall be set to
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.Dv RMAN_ARRAY .
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The field
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.Va rm_descr
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shall be set to a string that describes the resource to be managed.
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The
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.Va rm_start
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and
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.Va rm_end
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fields may be set to limit the range of acceptable resource addresses.
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If these fields are not set,
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.Fn rman_init
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will initialize them to allow the entire range of resource addresses.
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It also initializes any mutexes associated with the structure.
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If
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.Fn rman_init
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fails to initialize the mutex, it will return
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.Er ENOMEM ; otherwise it will return 0 and
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.Fa rm
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will be initialized.
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.Pp
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The
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.Fn rman_fini
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function frees any structures associated with the structure
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pointed to by the
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.Fa rm
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argument.
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If any of the resources within the managed region have the
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.Dv RF_ALLOCATED
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flag set, it will return
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.Er EBUSY ;
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otherwise, any mutexes associated with the structure will be released
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and destroyed, and the function will return 0.
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.Pp
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The
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.Fn rman_manage_region
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function establishes the concept of a region which is under
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.Nm
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control.
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The
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.Fa rman
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argument points to the region descriptor.
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The
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.Fa start
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and
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.Fa end
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arguments specify the bounds of the region.
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If successful,
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.Fn rman_manage_region
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will return 0.
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If the region overlaps with an existing region, it will return
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.Er EBUSY .
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If any part of the region falls outside of the valid address range for
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.Fa rm ,
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it will return
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.Er EINVAL .
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.Er ENOMEM
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will be returned when
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.Fn rman_manage_region
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failed to allocate memory for the region.
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.Pp
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The
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.Fn rman_init_from_resource
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function is a wrapper routine to create a resource manager backed by an
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existing resource.
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It initializes
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.Fa rm
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using
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.Fn rman_init
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and then adds a region to
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.Fa rm
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corresponding to the address range allocated to
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.Fa r
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via
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.Fn rman_manage_region .
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.Pp
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The
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.Fn rman_first_free_region
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and
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.Fn rman_last_free_region
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functions can be used to query a resource manager for its first
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.Pq or last
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unallocated region.
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If
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.Fa rm
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contains no free region,
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these functions will return
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.Er ENOENT .
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Otherwise,
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.Fa *start
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and
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.Fa *end
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are set to the bounds of the free region and zero is returned.
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.Pp
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The
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.Fn rman_reserve_resource
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function is where the bulk of the
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.Nm
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logic is located.
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It attempts to reserve a contiguous range in the specified region
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.Fa rm
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for the use of the device
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.Fa dev .
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The caller can specify the
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.Fa start
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and
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.Fa end
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of an acceptable range,
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required alignment,
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and the code will attempt to find a free segment which fits.
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The
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.Fa start
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argument is the lowest acceptable starting value of the resource.
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The
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.Fa end
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argument is the highest acceptable ending value of the resource.
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Therefore,
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.Fa start No + Fa count No \- 1
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must be \[<=]
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.Fa end
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for any allocation to happen.
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The alignment requirement
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.Pq if any
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is specified in
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.Fa flags .
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Often the
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.Dv RF_ALIGNMENT_LOG2
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macro is used to specify alignment to a power-of-2 size, or
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.Fn rman_make_alignment_flags
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can be used to compute the
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.Fa flags
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value at runtime.
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A shared segment will be allocated if the
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.Dv RF_SHAREABLE
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flag is set, otherwise an exclusive segment will be allocated.
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If this shared segment already exists, the caller has its device
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added to the list of consumers.
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.Pp
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The
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.Fn rman_make_alignment_flags
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function returns the flag mask corresponding to the desired alignment
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.Fa size .
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This should be used when calling
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.Fn rman_reserve_resource_bound .
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.Pp
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The
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.Fn rman_is_region_manager
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function returns true if the allocated resource
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.Fa r
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was allocated from
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.Fa rm .
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Otherwise,
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it returns false.
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.Pp
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The
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.Fn rman_adjust_resource
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function is used to adjust the reserved address range of an allocated resource
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to reserve
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.Fa start
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through
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.Fa end .
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It can be used to grow or shrink one or both ends of the resource range.
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The current implementation does not support entirely relocating the resource
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and will fail with
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.Er EINVAL
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if the new resource range does not overlap the old resource range.
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If either end of the resource range grows and the new resource range would
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conflict with another allocated resource,
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the function will fail with
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.Er EBUSY .
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The
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.Fn rman_adjust_resource
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function does not support adjusting the resource range for shared resources
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and will fail such attempts with
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.Er EINVAL .
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Upon success,
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the resource
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.Fa r
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will have a start address of
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.Fa start
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and an end address of
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.Fa end
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and the function will return zero.
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Note that none of the constraints of the original allocation request such
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as alignment or boundary restrictions are checked by
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.Fn rman_adjust_resource .
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It is the caller's responsibility to enforce any such requirements.
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.Pp
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The
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.Fn rman_release_resource
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function releases the reserved resource
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.Fa r .
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It may attempt to merge adjacent free resources.
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.Pp
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The
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.Fn rman_activate_resource
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function marks a resource as active, by setting the
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.Dv RF_ACTIVE
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flag.
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If this is a time shared resource, and the caller has not yet acquired
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the resource, the function returns
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.Er EBUSY .
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.Pp
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The
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.Fn rman_deactivate_resource
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function marks a resource
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.Fa r
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as inactive, by clearing the
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.Dv RF_ACTIVE
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flag.
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If other consumers are waiting for this range, it will wakeup their threads.
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.Pp
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The
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.Fn rman_get_start ,
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.Fn rman_get_end ,
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.Fn rman_get_size ,
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and
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.Fn rman_get_flags
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functions return the bounds, size and flags of the previously reserved
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resource
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.Fa r .
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.Pp
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The
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.Fn rman_set_bustag
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function associates a
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.Vt bus_space_tag_t
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.Fa t
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with the resource
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.Fa r .
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The
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.Fn rman_get_bustag
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function is used to retrieve this tag once set.
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.Pp
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The
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.Fn rman_set_bushandle
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function associates a
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.Vt bus_space_handle_t
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.Fa h
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with the resource
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.Fa r .
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The
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.Fn rman_get_bushandle
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function is used to retrieve this handle once set.
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.Pp
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The
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.Fn rman_set_virtual
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function is used to associate a kernel virtual address with a resource
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.Fa r .
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The
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.Fn rman_get_virtual
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function can be used to retrieve the KVA once set.
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.Pp
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The
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.Fn rman_set_mapping
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function is used to associate a resource mapping with a resource
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.Fa r .
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The mapping must cover the entire resource.
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Setting a mapping sets the associated
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.Xr bus_space 9
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handle and tag for
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.Fa r
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as well as the kernel virtual address if the mapping contains one.
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These individual values can be retrieved via
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.Fn rman_get_bushandle ,
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.Fn rman_get_bustag ,
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and
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.Fn rman_get_virtual .
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.Pp
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The
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.Fn rman_get_mapping
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function can be used to retrieve the associated resource mapping once set.
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.Pp
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The
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.Fn rman_set_rid
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function associates a resource identifier with a resource
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.Fa r .
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The
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.Fn rman_get_rid
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function retrieves this RID.
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.Pp
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The
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.Fn rman_set_type
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function associates a resource type with a resource
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.Fa r .
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The
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.Fn rman_get_type
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function retrieves this type.
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.Pp
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The
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.Fn rman_get_device
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function returns a pointer to the device which reserved the resource
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.Fa r .
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.Sh SEE ALSO
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.Xr bus_activate_resource 9 ,
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.Xr bus_adjust_resource 9 ,
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.Xr bus_alloc_resource 9 ,
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.Xr bus_map_resource 9 ,
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.Xr bus_release_resource 9 ,
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.Xr bus_set_resource 9 ,
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.Xr bus_space 9 ,
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.Xr mutex 9
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.Sh AUTHORS
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This manual page was written by
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.An Bruce M Simpson Aq Mt bms@spc.org .
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