1.\" Copyright (c) 2000 Alexander Langer
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27.\" $FreeBSD: src/share/man/man9/bus_alloc_resource.9,v 1.2.2.10 2004/03/17 17:54:24 njl Exp $
28.\"
29.Dd May 18, 2000
30.Dt BUS_ALLOC_RESOURCE 9
31.Os
32.Sh NAME
33.Nm bus_alloc_resource ,
34.Nm bus_alloc_resource_any
35.Nd alloc resources on a bus
36.Sh SYNOPSIS
37.In sys/param.h
38.In sys/bus.h
39.Pp
40.In sys/rman.h
41.In sys/resource.h
42.Ft struct resource *
43.Fn bus_alloc_resource "device_t dev" "int type" "int *rid" "u_long start" "u_long end" "u_long count" "u_int flags"
44.Ft struct resource *
45.Fn bus_alloc_resource_any "device_t dev" "int type" "int *rid" "u_int flags"
46.Sh DESCRIPTION
47This is an easy interface to the resource-management functions.
48It hides the indirection through the parent's method table.
49This function generally should be called in attach, but (except in some
50race cases) never earlier.
51.Pp
52The
53.Fn bus_alloc_resource_any
54function is a convenience wrapper for
55.Fn bus_alloc_resource .
56It sets the values for
57.Fa start ,
58.Fa end ,
59and
60.Fa count
61to the default resource (see description of
62.Fa start
63below).
64.Pp
65The arguments are as follows:
66.Bl -item
67.It
68.Fa dev
69is the device that requests ownership of the resource.
70Before allocation, the resource is owned by the parent bus.
71.It
72.Fa type
73is the type of resource you want to allocate.
74It is one of:
75.Bl -tag -width ".Dv SYS_RES_MEMORY"
76.It Dv SYS_RES_IRQ
77for IRQs
78.It Dv SYS_RES_DRQ
79for ISA DMA lines
80.It Dv SYS_RES_IOPORT
81for I/O ports
82.It Dv SYS_RES_MEMORY
83for I/O memory
84.El
85.It
86.Fa rid
87points to a bus specific handle that identifies the resource being allocated.
88For ISA this is an index into an array of resources that have been setup
89for this device by either the PnP mechanism, or via the hints mechanism.
90For PCCARD, similar things are used as of writing,
91but that may change in the future with newcard.
92For PCI it just happens to be the offset into pci config space which has
93a word that describes the resource.
94The bus methods are free to change the RIDs that they are given as a parameter.
95You must not depend on the value you gave it earlier.
96.It
97.Fa start
98and
99.Fa end
100are the start/end addresses of the resource.
101If you specify values of
102.Dv 0
103for start and
104.Dv ~0
105for end, the default values for the bus are calculated.
106.It
107.Fa count
108is the size of the resource, e.g. the size of an I/O port (often
109.Dv 1
110on PCI and device-dependent on ISA and PCCARD).
111If you specified the default values for
112.Fa start
113and
114.Fa end ,
115then the default value of the bus is used if
116.Fa count
117is smaller than the default value and
118.Fa count
119is used, if it is bigger than the default value.
120.It
121.Fa flags
122sets the flags for the resource.
123You can set one or more of these flags:
124.Bl -tag -width ".Dv RF_SHAREABLE"
125.It Dv RF_ALLOCATED
126resource has been reserved.
127The resource still needs to be activated with
128.Xr rman_activate_resource 9 .
129.It Dv RF_ACTIVE
130activate resource atomically.
131.It Dv RF_SHAREABLE
132resource permits contemporaneous sharing.
133Should always be set unless you know, that the resource cannot be shared.
134It is the bus-code's task to filter out the flag if the bus doesn't
135support sharing, which is, for example, the case for pccard/cardbus,
136which can or cannot share devices, depending on the bus.
137.It Dv RF_TIMESHARE
138resource permits time-division sharing.
139.El
140.El
141.Sh RETURN VALUES
142A pointer to
143.Va struct res
144is returned on success, a null pointer otherwise.
145.Sh EXAMPLES
146This is some example code.
147The values of
148.Va portid
149and
150.Va irqid
151should be saved in the softc of the device after these calls.
152.Bd -literal
153	struct resource *portres, irqres;
154	int portid, irqid;
155
156	portid = 0;
157	irqid = 0;
158	portres = bus_alloc_resource(dev, SYS_RES_IOPORT, &portid,
159			0ul, ~0ul, 32, RF_ACTIVE);
160	irqres = bus_alloc_resource_any(dev, SYS_RES_IRQ, &irqid,
161			RF_ACTIVE | RF_SHAREABLE);
162.Ed
163.Sh SEE ALSO
164.Xr bus_release_resource 9 ,
165.Xr device 9 ,
166.Xr driver 9
167.Sh AUTHORS
168.An -nosplit
169This man page was written by
170.An Alexander Langer Aq alex@big.endian.de
171with parts by
172.An Warner Losh Aq imp@FreeBSD.org .
173