xref: /freebsd/share/man/man9/rman.9 (revision acd3428b7d3e94cef0e1881c868cb4b131d4ff41)
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26.\" $FreeBSD$
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28.Dd March 15, 2005
29.Dt RMAN 9
30.Os
31.Sh NAME
32.Nm rman ,
33.Nm rman_activate_resource ,
34.Nm rman_await_resource ,
35.Nm rman_deactivate_resource ,
36.Nm rman_fini ,
37.Nm rman_init ,
38.Nm rman_manage_region ,
39.Nm rman_release_resource ,
40.Nm rman_reserve_resource ,
41.Nm rman_reserve_resource_bound ,
42.Nm rman_make_alignment_flags ,
43.Nm rman_get_start ,
44.Nm rman_get_end ,
45.Nm rman_get_device ,
46.Nm rman_get_size ,
47.Nm rman_get_flags ,
48.Nm rman_set_virtual ,
49.Nm rman_get_virtual ,
50.Nm rman_set_bustag ,
51.Nm rman_get_bustag ,
52.Nm rman_set_bushandle ,
53.Nm rman_get_bushandle ,
54.Nm rman_set_rid ,
55.Nm rman_get_rid
56.Nd resource management functions
57.Sh SYNOPSIS
58.In sys/rman.h
59.Ft int
60.Fn rman_activate_resource "struct resource *r"
61.Ft int
62.Fn rman_await_resource "struct resource *r" "int pri2" "int timo"
63.Ft int
64.Fn rman_deactivate_resource "struct resource *r"
65.Ft int
66.Fn rman_fini "struct rman *rm"
67.Ft int
68.Fn rman_init "struct rman *rm"
69.Ft int
70.Fn rman_manage_region "struct rman *rm" "u_long start" "u_long end"
71.Ft int
72.Fn rman_release_resource "struct resource *r"
73.Ft "struct resource *"
74.Fo rman_reserve_resource
75.Fa "struct rman *rm" "u_long start" "u_long end" "u_long count"
76.Fa "u_int flags" "struct device *dev"
77.Fc
78.Ft "struct resource *"
79.Fo rman_reserve_resource_bound
80.Fa "struct rman *rm" "u_long start" "u_long end" "u_long count"
81.Fa "u_long bound" "u_int flags" "struct device *dev"
82.Fc
83.Ft uint32_t
84.Fn rman_make_alignment_flags "uint32_t size"
85.Ft u_long
86.Fn rman_get_start "struct resource *r"
87.Ft u_long
88.Fn rman_get_end "struct resource *r"
89.Ft "struct device *"
90.Fn rman_get_device "struct resource *r"
91.Ft u_long
92.Fn rman_get_size "struct resource *r"
93.Ft u_int
94.Fn rman_get_flags "struct resource *r"
95.Ft void
96.Fn rman_set_virtual "struct resource *r" "void *v"
97.Ft "void *"
98.Fn rman_get_virtual "struct resource *r"
99.Ft void
100.Fn rman_set_bustag "struct resource *r" "bus_space_tag_t t"
101.Ft bus_space_tag_t
102.Fn rman_get_bustag "struct resource *r"
103.Ft void
104.Fn rman_set_bushandle "struct resource *r" "bus_space_handle_t h"
105.Ft bus_space_handle_t
106.Fn rman_get_bushandle "struct resource *r"
107.Ft void
108.Fn rman_set_rid "struct resource *r" "int rid"
109.Ft int
110.Fn rman_get_rid "struct resource *r"
111.Sh DESCRIPTION
112The
113.Nm
114set of functions provides a flexible resource management abstraction.
115It is used extensively by the bus management code.
116It implements the abstractions of region and resource.
117A region descriptor is used to manage a region; this could be memory or
118some other form of bus space.
119.Pp
120Each region has a set of bounds.
121Within these bounds, allocated segments may reside.
122Each segment, termed a resource, has several properties which are
123represented by a 16-bit flag register, as follows.
124.Bd -literal
125#define RF_ALLOCATED    0x0001 /* resource has been reserved */
126#define RF_ACTIVE       0x0002 /* resource allocation has been activated */
127#define RF_SHAREABLE    0x0004 /* resource permits contemporaneous sharing */
128#define RF_TIMESHARE    0x0008 /* resource permits time-division sharing */
129#define RF_WANTED       0x0010 /* somebody is waiting for this resource */
130#define RF_FIRSTSHARE   0x0020 /* first in sharing list */
131#define RF_PREFETCHABLE 0x0040 /* resource is prefetchable */
132.Ed
133.Pp
134The remainder of the flag bits are used to represent the desired alignment
135of the resource within the region.
136.Pp
137The
138.Fn rman_init
139function initializes the region descriptor, pointed to by the
140.Fa rm
141argument, for use with the resource management functions.
142It also initializes any mutexes associated with the structure.
143.Pp
144The
145.Fn rman_fini
146function frees any structures associated with the structure
147pointed to by the
148.Fa rm
149argument.
150If any of the resources within the managed region have the
151.Dv RF_ALLOCATED
152flag set, it will return
153.Er EBUSY ;
154otherwise, any mutexes associated with the structure will be released
155and destroyed, and the function will return 0.
156.Pp
157The
158.Fn rman_manage_region
159function establishes the concept of a region which is under
160.Nm
161control.
162The
163.Fa rman
164argument points to the region descriptor.
165The
166.Fa start
167and
168.Fa end
169arguments specify the bounds of the region.
170.Pp
171.Em NOTE :
172This interface is not robust against programming errors which
173add multiple copies of the same region.
174.Pp
175The
176.Fn rman_reserve_resource_bound
177function is where the bulk of the
178.Nm
179logic is located.
180It attempts to reserve a contiguous range in the specified region
181.Fa rm
182for the use of the device
183.Fa dev .
184The caller can specify the
185.Fa start
186and
187.Fa end
188of an acceptable range, as well as
189alignment, and the code will attempt to find a free segment which fits.
190The
191.Fa start
192argument is the lowest acceptable starting value of the resource.
193The
194.Fa end
195argument is the highest acceptable ending value of the resource.
196Therefore,
197.Fa start No + Fa count No \- 1
198must be \[<=]
199.Fa end
200for any allocation to happen.
201The default behavior is to allocate an exclusive segment, unless the
202.Dv RF_SHAREABLE
203or
204.Dv RF_TIMESHARE
205flags are set, in which case a shared
206segment will be allocated.
207If this shared segment already exists, the caller has its device
208added to the list of consumers.
209.Pp
210The
211.Fn rman_reserve_resource
212function is used to reserve resources within a previously established region.
213It is a simplified interface to
214.Fn rman_reserve_resource_bound
215which passes 0 for the
216.Fa flags
217argument.
218.Pp
219The
220.Fn rman_make_alignment_flags
221function returns the flag mask corresponding to the desired alignment
222.Fa size .
223This should be used when calling
224.Fn rman_reserve_resource_bound .
225.Pp
226The
227.Fn rman_release_resource
228function releases the reserved resource
229.Fa r .
230It may attempt to merge adjacent free resources.
231.Pp
232The
233.Fn rman_activate_resource
234function marks a resource as active, by setting the
235.Dv RF_ACTIVE
236flag.
237If this is a time shared resource, and the caller has not yet acquired
238the resource, the function returns
239.Er EBUSY .
240.Pp
241The
242.Fn rman_deactivate_resource
243function marks a resource
244.Fa r
245as inactive, by clearing the
246.Dv RF_ACTIVE
247flag.
248If other consumers are waiting for this range, it will wakeup their threads.
249.Pp
250The
251.Fn rman_await_resource
252function performs an asynchronous wait for a resource
253.Fa r
254to become inactive, that is, for the
255.Dv RF_ACTIVE
256flag to be cleared.
257It is used to enable cooperative sharing of a resource
258which can only be safely used by one thread at a time.
259The arguments
260.Fa pri
261and
262.Fa timo
263are passed to the
264.Fn rman_await_resource
265function.
266.Pp
267The
268.Fn rman_get_start ,
269.Fn rman_get_end ,
270.Fn rman_get_size ,
271and
272.Fn rman_get_flags
273functions return the bounds, size and flags of the previously reserved
274resource
275.Fa r .
276.Pp
277The
278.Fn rman_set_bustag
279function associates a
280.Vt bus_space_tag_t
281.Fa t
282with the resource
283.Fa r .
284The
285.Fn rman_get_bustag
286function is used to retrieve this tag once set.
287.Pp
288The
289.Fn rman_set_bushandle
290function associates a
291.Vt bus_space_handle_t
292.Fa h
293with the resource
294.Fa r .
295The
296.Fn rman_get_bushandle
297function is used to retrieve this handle once set.
298.Pp
299The
300.Fn rman_set_virtual
301function is used to associate a kernel virtual address with a resource
302.Fa r .
303The
304.Fn rman_get_virtual
305function can be used to retrieve the KVA once set.
306.Pp
307The
308.Fn rman_set_rid
309function associates a resource identifier with a resource
310.Fa r .
311The
312.Fn rman_get_rid
313function retrieves this RID.
314.Pp
315The
316.Fn rman_get_device
317function returns a pointer to the device which reserved the resource
318.Fa r .
319.Sh SEE ALSO
320.Xr bus_activate_resource 9 ,
321.Xr bus_alloc_resource 9 ,
322.Xr bus_release_resource 9 ,
323.Xr bus_set_resource 9 ,
324.Xr mutex 9
325.Sh AUTHORS
326This manual page was written by
327.An Bruce M Simpson Aq bms@spc.org .
328