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32 .Dt BUS_ALLOC_RESOURCE 9
35 .Nm bus_alloc_resource ,
36 .Nm bus_alloc_resource_any ,
37 .Nm bus_alloc_resource_anywhere
38 .Nd allocate resources from a parent bus
45 .In machine/resource.h
47 .Fo bus_alloc_resource
48 .Fa "device_t dev" "int type" "int *rid" "rman_res_t start" "rman_res_t end"
49 .Fa "rman_res_t count" "u_int flags"
52 .Fn bus_alloc_resource_any "device_t dev" "int type" "int *rid" "u_int flags"
54 .Fo bus_alloc_resource_anywhere
55 .Fa "device_t dev" "int type" "int *rid" "rman_res_t count" "u_int flags"
58 This is an easy interface to the resource-management functions.
59 It hides the indirection through the parent's method table.
60 This function generally should be called in attach, but (except in some
61 rare cases) never earlier.
64 .Fn bus_alloc_resource_any
66 .Fn bus_alloc_resource_anywhere
67 functions are convenience wrappers for
68 .Fn bus_alloc_resource .
69 .Fn bus_alloc_resource_any
75 to the default resource (see description of
78 .Fn bus_alloc_resource_anywhere
83 to the default resource and uses the provided
87 The arguments are as follows:
91 is the device that requests ownership of the resource.
92 Before allocation, the resource is owned by the parent bus.
95 is the type of resource you want to allocate.
97 .Bl -tag -width SYS_RES_MEMORY
104 .It Dv SYS_RES_IOPORT
106 .It Dv SYS_RES_MEMORY
111 points to a bus specific handle that identifies the resource being allocated.
112 For ISA this is an index into an array of resources that have been setup
113 for this device by either the PnP mechanism, or via the hints mechanism.
114 For PCCARD, this is an index into the array of resources described by the PC Card's
116 For PCI, the offset into PCI config space which has the BAR to use to access
118 The bus methods are free to change the RIDs that they are given as a parameter.
119 You must not depend on the value you gave it earlier.
124 are the start/end addresses of the resource.
125 If you specify values of 0ul for
131 the default values for the bus are calculated.
134 is the size of the resource.
135 For example, the size of an I/O port is usually 1 byte (but some devices
137 If you specified the default values for
141 then the default value of the bus is used if
143 is smaller than the default value and
145 is used, if it is bigger than the default value.
148 sets the flags for the resource.
149 You can set one or more of these flags:
150 .Bl -tag -width RF_SHAREABLE
152 resource has been reserved.
153 The resource still needs to be activated with
154 .Xr bus_activate_resource 9 .
156 activate resource atomically.
157 .It Dv RF_PREFETCHABLE
158 resource is prefetchable.
160 resource permits contemporaneous sharing.
161 It should always be set unless you know that the resource cannot be shared.
162 It is the bus driver's task to filter out the flag if the bus does not
166 cannot share IRQs while
170 do not establish implicit mapping when activated via
171 .Xr bus_activate_resource 9 .
177 is returned on success, a null pointer otherwise.
179 This is some example code that allocates a 32 byte I/O port range and an IRQ.
184 should be saved in the softc of the device after these calls.
186 struct resource *portres, *irqres;
191 portres = bus_alloc_resource(dev, SYS_RES_IOPORT, &portid,
192 0ul, ~0ul, 32, RF_ACTIVE);
193 irqres = bus_alloc_resource_any(dev, SYS_RES_IRQ, &irqid,
194 RF_ACTIVE | RF_SHAREABLE);
197 .Xr bus_activate_resource 9 ,
198 .Xr bus_adjust_resource 9 ,
199 .Xr bus_map_resource 9 ,
200 .Xr bus_release_resource 9 ,
205 This manual page was written by
206 .An Alexander Langer Aq Mt alex@big.endian.de
208 .An Warner Losh Aq Mt imp@FreeBSD.org .