xref: /freebsd/share/man/man9/bus_map_resource.9 (revision c697fb7f)
1.\" -*- nroff -*-
2.\"
3.\" Copyright (c) 2016 John H. Baldwin <jhb@FreeBSD.org>
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\"    notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\"    notice, this list of conditions and the following disclaimer in the
12.\"    documentation and/or other materials provided with the distribution.
13.\"
14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24.\" SUCH DAMAGE.
25.\"
26.\" $FreeBSD$
27.\"
28.Dd February 5, 2018
29.Dt BUS_MAP_RESOURCE 9
30.Os
31.Sh NAME
32.Nm bus_map_resource , bus_unmap_resource , resource_init_map_request
33.Nd map or unmap an active resource
34.Sh SYNOPSIS
35.In sys/param.h
36.In sys/bus.h
37.Pp
38.In machine/bus.h
39.In sys/rman.h
40.In machine/resource.h
41.Ft int
42.Fo bus_map_resource
43.Fa "device_t dev" "int type" "struct resource *r"
44.Fa "struct resource_map_request *args" "struct resource_map *map"
45.Fc
46.Ft int
47.Fo bus_unmap_resource
48.Fa "device_t dev" "int type" "struct resource *r" "struct resource_map *map"
49.Fc
50.Ft void
51.Fn resource_init_map_request "struct resource_map_request *args"
52.Sh DESCRIPTION
53These functions create or destroy a mapping of a previously activated
54resource.
55Mappings permit CPU access to the resource via the
56.Xr bus_space 9
57API.
58.Pp
59The arguments are as follows:
60.Bl -tag -width indent
61.It Fa dev
62The device that owns the resource.
63.It Fa type
64The type of resource to map.
65It is one of:
66.Pp
67.Bl -tag -width ".Dv SYS_RES_MEMORY" -compact
68.It Dv SYS_RES_IOPORT
69for I/O ports
70.It Dv SYS_RES_MEMORY
71for I/O memory
72.El
73.It Fa r
74A pointer to the
75.Vt "struct resource"
76returned by
77.Xr bus_alloc_resource 9 .
78.It Fa args
79A set of optional properties to apply when creating a mapping.
80This argument can be set to
81.Dv NULL
82to request a mapping of the entire resource with the default properties.
83.It Fa map
84The resource mapping to create or destroy.
85.El
86.Ss Resource Mappings
87Resource mappings are described by a
88.Vt "struct resource_map"
89object.
90This structure contains a
91.Xr bus_space 9
92tag and handle in the
93.Va r_bustag
94and
95.Va r_bushandle
96members that can be used for CPU access to the mapping.
97The structure also contains a
98.Va r_vaddr
99member which contains the virtual address of the mapping if one exists.
100.Pp
101The wrapper API for
102.Vt "struct resource"
103objects described in
104.Xr bus_activate_resource 9
105can also be used with
106.Vt "struct resource_map" .
107For example,
108a pointer to a mapping object can be passed as the first argument to
109.Fn bus_read_4 .
110This wrapper API is preferred over using the
111.Va r_bustag
112and
113.Va r_bushandle
114members directly.
115.Ss Optional Mapping Properties
116The
117.Vt "struct resource_map_request"
118object passed in
119.Fa args
120can be used to specify optional properties of a mapping.
121The structure must be initialized by invoking
122.Fn resource_init_map_request .
123Properties are then specified by setting one or more of these members:
124.Bl -tag -width indent
125.It Va offset , length
126These two members specify a region of the resource to map.
127By default a mapping is created for the entire resource.
128The
129.Va offset
130is relative to the start of the resource.
131.It Va memattr
132Specifies a memory attribute to use when mapping the resource.
133By default memory mappings use the
134.Dv VM_MEMATTR_UNCACHEABLE
135attribute.
136.El
137.Sh RETURN VALUES
138Zero is returned on success, otherwise an error is returned.
139.Sh EXAMPLES
140This maps a PCI memory BAR with the write-combining memory attribute and
141reads the first 32-bit word:
142.Bd -literal
143	struct resource *r;
144	struct resource_map map;
145	struct resource_map_request req;
146	uint32_t val;
147	int rid;
148
149	rid = PCIR_BAR(0);
150	r = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE |
151	    RF_UNMAPPED);
152	resource_init_map_request(&req);
153	req.memattr = VM_MEMATTR_WRITE_COMBINING;
154	bus_map_resource(dev, SYS_RES_MEMORY, r, &req, &map);
155	val = bus_read_4(&map, 0);
156.Ed
157.Sh SEE ALSO
158.Xr bus_activate_resource 9 ,
159.Xr bus_alloc_resource 9 ,
160.Xr bus_space 9 ,
161.Xr device 9 ,
162.Xr driver 9
163.Sh AUTHORS
164This manual page was written by
165.An John Baldwin Aq Mt jhb@FreeBSD.org .
166