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RMAN(9)			 BSD 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	-- re-
     source 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 ab-
     straction.	 It is used extensively	by the bus management code.  It	imple-
     ments 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

     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 is
     required that the fields rm_type and rm_descr of struct rman be set be-
     fore calling rman_init().	The field rm_type shall	be set to RMAN_ARRAY.
     The field rm_descr	shall be set to	a string that describes	the resource
     to	be managed.  It	also initializes any mutexes associated	with the
     structure.	 If rman_init()	fails to initalize the mutex, it will return
     ENOMEM; otherwise it will return 0	and rm will be initalized.

     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 de-
     scriptor.	The start and end arguments specify the	bounds of the region.
     If	successful, rman_manage_region() will return 0.	 If the	region over-
     laps with an existing region, it will return EBUSY.  ENOMEM will be re-
     turn when rman_manage_region() failed to allocate memory for the 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 start argument
     is	the lowest acceptable starting value of	the resource.  The end argu-
     ment is the highest acceptable ending value of the	resource.  Therefore,
     start + count - 1 must be <= end for any allocation to happen.  The de-
     fault behavior is to allocate an exclusive	segment, unless	the
     RF_SHAREABLE or RF_TIMESHARE flags	are set, in which case a shared	seg-
     ment will be allocated.  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 ad-
     dress 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 re-
     source r.	The rman_get_rid() function retrieves this RID.

     The rman_get_device() function returns a pointer to the device which re-
     served the	resource r.

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

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

BSD				April 29, 2007				   BSD


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