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RMAN(9)		       FreeBSD Kernel Developer's Manual	       RMAN(9)

     rman, rman_activate_resource, rman_await_resource,
     rman_deactivate_resource, rman_fini, rman_init, rman_manage_region,
     rman_release_resource, rman_reserve_resource,
     rman_reserve_resource_bound, rman_make_alignment_flags, rman_get_start,
     rman_get_end, rman_get_device, rman_get_size, rman_get_flags,
     rman_set_virtual, rman_get_virtual, rman_set_bustag, rman_get_bustag,
     rman_set_bushandle, rman_get_bushandle, rman_set_rid, rman_get_rid	--
     resource management functions

     #include <sys/rman.h>

     rman_activate_resource(struct resource *r);

     rman_await_resource(struct	resource *r, int pri2, int timo);

     rman_deactivate_resource(struct resource *r);

     rman_fini(struct rman *rm);

     rman_init(struct rman *rm);

     rman_manage_region(struct rman *rm, u_long	start, u_long end);

     rman_release_resource(struct resource *r);

     struct resource *
     rman_reserve_resource(struct rman *rm, u_long start, u_long end,
	 u_long	count, u_int flags, struct device *dev);

     struct resource *
     rman_reserve_resource_bound(struct	rman *rm, u_long start,	u_long end,
	 u_long	count, u_long bound, u_int flags, struct device	*dev);

     rman_make_alignment_flags(uint32_t	size);

     rman_get_start(struct resource *r);

     rman_get_end(struct resource *r);

     struct device *
     rman_get_device(struct resource *r);

     rman_get_size(struct resource *r);

     rman_get_flags(struct resource *r);

     rman_set_virtual(struct resource *r, void *v);

     void *
     rman_get_virtual(struct resource *r);

     rman_set_bustag(struct resource *r, bus_space_tag_t t);

     rman_get_bustag(struct resource *r);

     rman_set_bushandle(struct resource	*r, bus_space_handle_t h);

     rman_get_bushandle(struct resource	*r);

     rman_set_rid(struct resource *r, int rid);

     rman_get_rid(struct resource *r);

     The rman set of functions provides	a flexible resource management
     abstraction.  It is used extensively by the bus management	code.  It
     implements	the abstractions of region and resource.  A region descriptor
     is	used to	manage a region; this could be memory or some other form of
     bus space.

     Each region has a set of bounds.  Within these bounds, allocated segments
     may reside.  Each segment,	termed a resource, has several properties
     which are represented by a	16-bit flag register, as follows.

     #define RF_ALLOCATED    0x0001 /* resource	has been reserved */
     #define RF_ACTIVE	     0x0002 /* resource	allocation has been activated */
     #define RF_SHAREABLE    0x0004 /* resource	permits	contemporaneous	sharing	*/
     #define RF_TIMESHARE    0x0008 /* resource	permits	time-division sharing */
     #define RF_WANTED	     0x0010 /* somebody	is waiting for this resource */
     #define RF_FIRSTSHARE   0x0020 /* first in	sharing	list */
     #define RF_PREFETCHABLE 0x0040 /* resource	is prefetchable	*/

     The remainder of the flag bits are	used to	represent the desired align-
     ment of the resource within the region.

     The rman_init() function initializes the region descriptor, pointed to by
     the rm argument, for use with the resource	management functions.  It also
     initializes any mutexes associated	with the structure.

     The rman_fini() function frees any	structures associated with the struc-
     ture pointed to by	the rm argument.  If any of the	resources within the
     managed region have the RF_ALLOCATED flag set, it will return EBUSY; oth-
     erwise, any mutexes associated with the structure will be released	and
     destroyed,	and the	function will return 0.

     The rman_manage_region() function establishes the concept of a region
     which is under rman control.  The rman argument points to the region
     descriptor.  The start and	end arguments specify the bounds of the

     NOTE: This	interface is not robust	against	programming errors which add
     multiple copies of	the same region.

     The rman_reserve_resource_bound() function	is where the bulk of the rman
     logic is located.	It attempts to reserve a contiguous range in the spec-
     ified region rm for the use of the	device dev.  The caller	can specify
     the start and end of an acceptable	range, as well as alignment, and the
     code will attempt to find a free segment which fits.  The default behav-
     ior is to allocate	an exclusive segment, unless the RF_SHAREABLE or
     RF_TIMESHARE flags	are set, in which case a shared	segment	will be	allo-
     cated.  If	this shared segment already exists, the	caller has its device
     added to the list of consumers.

     The rman_reserve_resource() function is used to reserve resources within
     a previously established region.  It is a simplified interface to
     rman_reserve_resource_bound() which passes	0 for the flags	argument.

     The rman_make_alignment_flags() function returns the flag mask corre-
     sponding to the desired alignment size.  This should be used when calling

     The rman_release_resource() function releases the reserved	resource r.
     It	may attempt to merge adjacent free resources.

     The rman_activate_resource() function marks a resource as active, by set-
     ting the RF_ACTIVE	flag.  If this is a time shared	resource, and the
     caller has	not yet	acquired the resource, the function returns EBUSY.

     The rman_deactivate_resource() function marks a resource r	as inactive,
     by	clearing the RF_ACTIVE flag.  If other consumers are waiting for this
     range, it will wakeup their threads.

     The rman_await_resource() function	performs an asynchronous wait for a
     resource r	to become inactive, that is, for the RF_ACTIVE flag to be
     cleared.  It is used to enable cooperative	sharing	of a resource which
     can only be safely	used by	one thread at a	time.  The arguments pri and
     timo are passed to	the rman_await_resource() function.

     The rman_get_start(), rman_get_end(), rman_get_size(), and
     rman_get_flags() functions	return the bounds, size	and flags of the pre-
     viously reserved resource r.

     The rman_set_bustag() function associates a bus_space_tag_t t with	the
     resource r.  The rman_get_bustag()	function is used to retrieve this tag
     once set.

     The rman_set_bushandle() function associates a bus_space_handle_t h with
     the resource r.  The rman_get_bushandle() function	is used	to retrieve
     this handle once set.

     The rman_set_virtual() function is	used to	associate a kernel virtual
     address with a resource r.	 The rman_get_virtual()	function can be	used
     to	retrieve the KVA once set.

     The rman_set_rid()	function associates a resource identifier with a
     resource r.  The rman_get_rid() function retrieves	this RID.

     The rman_get_device() function returns a pointer to the device which
     reserved the resource r.

     bus_activate_resource(9), bus_alloc_resource(9), bus_release_resource(9),
     bus_set_resource(9), mutex(9)

     This man page was written by Bruce	M Simpson <>.

FreeBSD	11.1			 May 12, 2003			  FreeBSD 11.1


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