xref: /freebsd/share/man/man9/bus_activate_resource.9 (revision a7623790fb345e6dc986dfd31df0ace115e6f2e4)
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25.\" $FreeBSD$
26.\"
27.Dd May 20, 2016
28.Dt BUS_ACTIVATE_RESOURCE 9
29.Os
30.Sh NAME
31.Nm bus_activate_resource , bus_deactivate_resource
32.Nd activate or deactivate a resource
33.Sh SYNOPSIS
34.In sys/param.h
35.In sys/bus.h
36.Pp
37.In machine/bus.h
38.In sys/rman.h
39.In machine/resource.h
40.Ft int
41.Fo bus_activate_resource
42.Fa "device_t dev" "int type" "int rid" "struct resource *r"
43.Fc
44.Ft int
45.Fo bus_deactivate_resource
46.Fa "device_t dev" "int type" "int rid" "struct resource *r"
47.Fc
48.Sh DESCRIPTION
49These functions activate or deactivate a previously allocated resource.
50In general, resources must be activated before they can be accessed by
51the driver.
52Bus drivers may perform additional actions to ensure that the resource is
53ready to be accessed.
54For example,
55the PCI bus driver enables memory decoding in a PCI device's command register
56when activating a memory resource.
57.Pp
58The arguments are as follows:
59.Bl -tag -width indent
60.It Fa dev
61The device that requests ownership of the resource.
62Before allocation, the resource is owned by the parent bus.
63.It Fa type
64The type of resource you want to allocate.
65It is one of:
66.Pp
67.Bl -tag -width ".Dv SYS_RES_MEMORY" -compact
68.It Dv PCI_RES_BUS
69for PCI bus numbers
70.It Dv SYS_RES_IRQ
71for IRQs
72.It Dv SYS_RES_DRQ
73for ISA DMA lines
74.It Dv SYS_RES_IOPORT
75for I/O ports
76.It Dv SYS_RES_MEMORY
77for I/O memory
78.El
79.It Fa rid
80A pointer to a bus specific handle that identifies the resource being allocated.
81.It Fa r
82A pointer to the
83.Vt "struct resource"
84returned by
85.Xr bus_alloc_resource 9 .
86.El
87.Ss Resource Mapping
88Resources which can be mapped for CPU access by a
89.Xr bus_space 9
90tag and handle will create a mapping of the entire resource when activated.
91The tag and handle for this mapping are stored in
92.Fa r
93and can be retrieved via
94.Xr rman_get_bustag 9
95and
96.Xr rman_get_bushandle 9 .
97These can be used with the
98.Xr bus_space 9
99API to access device registers or memory described by
100.Fa r .
101If the mapping is associated with a virtual address,
102the virtual address can be retrieved via
103.Xr rman_get_virtual 9 .
104.Pp
105This implicit mapping can be disabled by passing the
106.Dv RF_UNMAPPED
107flag to
108.Xr bus_alloc_resource 9 .
109A driver may use this if it wishes to allocate its own mappings of a resource
110using
111.Xr bus_map_resource 9 .
112.Pp
113A wrapper API for
114.Xr bus_space 9
115is also provided that accepts the associated resource as the first argument
116in place of the
117.Xr bus_space 9
118tag and handle.
119The functions in this wrapper API are named similarly to the
120.Xr bus_space 9
121API except that
122.Dq _space
123is removed from their name.
124For example,
125.Fn bus_read_4
126can be used in place of
127.Fn bus_space_read_4 .
128The wrapper API is preferred in new drivers.
129.Pp
130These two statements both read a 32-bit register at the start of a
131resource:
132.Bd -literal
133	bus_space_read_4(rman_get_bustag(res), rman_get_bushandle(res), 0);
134	bus_read_4(res, 0);
135.Ed
136.Sh RETURN VALUES
137Zero is returned on success, otherwise an error is returned.
138.Sh SEE ALSO
139.Xr bus_alloc_resource 9 ,
140.Xr bus_map_resource 9 ,
141.Xr bus_space 9 ,
142.Xr device 9 ,
143.Xr driver 9
144.Sh AUTHORS
145This manual page was written by
146.An Warner Losh Aq Mt imp@FreeBSD.org .
147