Add a pair of bus methods that can be used to "map" resources for direct CPU access using bus_space(9). bus_map_resource() creates a mapping and bus_unmap_resource() releases a previously created mapping. Mappings are described by 'struct resource_map' object. Pointers to these objects can be passed as the first argument to the bus_space wrapper API used for bus resources. Drivers that wish to map all of a resource using default settings (for example, using uncacheable memory attributes) do not need to change. However, drivers that wish to use non-default settings can now do so without jumping through hoops. First, an RF_UNMAPPED flag is added to request that a resource is not implicitly mapped with the default settings when it is activated. This permits other activation steps (such as enabling I/O or memory decoding in a device's PCI command register) to be taken without creating a mapping. Right now the AGP drivers don't set RF_ACTIVE to avoid using up a large amount of KVA to map the AGP aperture on 32-bit platforms. Once RF_UNMAPPED is supported on all platforms that support AGP this can be changed to using RF_UNMAPPED with RF_ACTIVE instead. Second, bus_map_resource accepts an optional structure that defines additional settings for a given mapping. For example, a driver can now request to map only a subset of a resource instead of the entire range. The AGP driver could also use this to only map the first page of the aperture (IIRC, it calls pmap_mapdev() directly to map the first page currently). I will also eventually change the PCI-PCI bridge driver to request mappings of the subset of the I/O window resource on its parent side to create mappings for child devices rather than passing child resources directly up to nexus to be mapped. This also permits bridges that do address translation to request suitable mappings from a resource on the "upper" side of the bus when mapping resources on the "lower" side of the bus. Another attribute that can be specified is an alternate memory attribute for memory-mapped resources. This can be used to request a Write-Combining mapping of a PCI BAR in an MI fashion. (Currently the drivers that do this call pmap_change_attr() directly for x86 only.) Note that this commit only adds the MI framework. Each platform needs to add support for handling RF_UNMAPPED and thew new bus_map/unmap_resource methods. Generally speaking, any drivers that are calling rman_set_bustag() and rman_set_bushandle() need to be updated. Discussed on: arch Reviewed by: cem Differential Revision: https://reviews.freebsd.org/D5237
477 lines
13 KiB
Groff
477 lines
13 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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.\" $FreeBSD$
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.\"
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.Dd May 20, 2016
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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_reserve_resource_bound ,
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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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.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" "struct device *dev"
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.Fc
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.Ft "struct resource *"
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.Fo rman_reserve_resource_bound
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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 "rman_res_t bound" "u_int flags" "struct device *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 "struct device *"
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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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.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_bound
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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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as well as a boundary restriction and required aligment,
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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 aligment 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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The
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.Fa bound
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argument may be set to specify a boundary restriction such that an
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allocated region may cross an address that is a multiple of the
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boundary.
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The
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.Fa bound
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argument must be a power of two.
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It may be set to zero to specify no boundary restriction.
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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_reserve_resource
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function is used to reserve resources within a previously established region.
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It is a simplified interface to
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.Fn rman_reserve_resource_bound
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which passes 0 for the
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.Fa bound
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argument.
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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_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_space 9 ,
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.Xr bus_set_resource 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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