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

NAME

     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

SYNOPSIS

     #include <sys/rman.h>

     int
     rman_activate_resource(struct resource *r);

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

     int
     rman_deactivate_resource(struct resource *r);

     int
     rman_fini(struct rman *rm);

     int
     rman_init(struct rman *rm);

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

     int
     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);

     uint32_t
     rman_make_alignment_flags(uint32_t size);

     u_long
     rman_get_start(struct resource *r);

     u_long
     rman_get_end(struct resource *r);

     struct device *
     rman_get_device(struct resource *r);

     u_long
     rman_get_size(struct resource *r);

     u_int
     rman_get_flags(struct resource *r);

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

     void *
     rman_get_virtual(struct resource *r);

     void
     rman_set_bustag(struct resource *r, bus_space_tag_t t);

     bus_space_tag_t
     rman_get_bustag(struct resource *r);

     void
     rman_set_bushandle(struct resource *r, bus_space_handle_t h);

     bus_space_handle_t
     rman_get_bushandle(struct resource *r);

     void
     rman_set_rid(struct resource *r, int rid);

     int
     rman_get_rid(struct resource *r);

DESCRIPTION

     The rman set of functions provides a flexible resource management abstraction.  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 space.

     Each region has a set of bounds.  Within these bounds, allocated segments may reside.  Each segment, termed a resource, has several proper-
     ties 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 alignment 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 before 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 associ-
     ated with the structure.  If rman_init() fails to initalize the mutex, it will return ENOMEM; otherwise it will return 0 and rm will be ini-
     talized.

     The rman_fini() function frees any structures associated with the structure 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; otherwise, 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 region.  If successful, rman_manage_region() will return 0.  If the region
     overlaps with an existing region, it will return EBUSY.  ENOMEM will be return 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
     specified 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 argument is the highest acceptable ending value of the resource.  Therefore, start + count - 1 must be <= end for any allocation to
     happen.  The default behavior is to allocate an exclusive segment, unless the RF_SHAREABLE or RF_TIMESHARE flags are set, in which case a
     shared segment 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 corresponding to the desired alignment size.  This should be used when calling
     rman_reserve_resource_bound().

     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 setting 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 previously
     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.

SEE ALSO

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

AUTHORS

     This manual page was written by Bruce M Simpson <bms@spc.org>.

BSD
								  April 29, 2007							       BSD