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RMAN(9) Kernel Developer's Manual RMAN(9) NAME rman, rman_activate_resource, rman_adjust_resource, rman_deactivate_resource, rman_fini, rman_init, rman_init_from_resource, rman_is_region_manager, rman_manage_region, rman_first_free_region, rman_last_free_region, rman_release_resource, rman_reserve_resource, rman_make_alignment_flags, rman_get_start, rman_get_end, rman_get_device, rman_get_size, rman_get_flags, rman_set_mapping, rman_get_mapping, rman_set_virtual, rman_get_virtual, rman_set_bustag, rman_get_bustag, rman_set_bushandle, rman_get_bushandle, rman_set_rid, rman_get_rid, rman_set_type, rman_get_type -- resource management functions SYNOPSIS #include <sys/types.h> #include <sys/rman.h> int rman_activate_resource(struct resource *r); int rman_adjust_resource(struct resource *r, rman_res_t start, rman_res_t end); int rman_deactivate_resource(struct resource *r); int rman_fini(struct rman *rm); int rman_init(struct rman *rm); int rman_init_from_resource(struct rman *rm, struct resource *r); int rman_is_region_manager(struct resource *r, struct rman *rm); int rman_manage_region(struct rman *rm, rman_res_t start, rman_res_t end); int rman_first_free_region(struct rman *rm, rman_res_t *start, rman_res_t *end); int rman_last_free_region(struct rman *rm, rman_res_t *start, rman_res_t *end); int rman_release_resource(struct resource *r); struct resource * rman_reserve_resource(struct rman *rm, rman_res_t start, rman_res_t end, rman_res_t count, u_int flags, device_t dev); uint32_t rman_make_alignment_flags(uint32_t size); rman_res_t rman_get_start(struct resource *r); rman_res_t rman_get_end(struct resource *r); device_t rman_get_device(struct resource *r); rman_res_t rman_get_size(struct resource *r); u_int rman_get_flags(struct resource *r); void rman_set_mapping(struct resource *r, struct resource_map *map); void rman_get_mapping(struct resource *r, struct resource_map *map); 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); void rman_set_type(struct resource *r, int type); int rman_get_type(struct resource *r); DESCRIPTION The rman set of functions provides a flexible resource management ab- straction. It is used extensively by the bus management code. It im- plements 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 seg- ments 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_FIRSTSHARE 0x0020 /* first in sharing list */ #define RF_PREFETCHABLE 0x0040 /* resource is prefetchable */ #define RF_UNMAPPED 0x0100 /* don't map resource when activating */ Bits 15:10 of the flag register 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. The rm_start and rm_end fields may be set to limit the range of acceptable resource addresses. If these fields are not set, rman_init() will initialize them to allow the entire range of resource addresses. It also initializes any mutexes associated with the structure. If rman_init() fails to initialize the mutex, it will return ENOMEM; otherwise it will return 0 and rm will be initialized. 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 re- turn 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 re- gion. If successful, rman_manage_region() will return 0. If the re- gion overlaps with an existing region, it will return EBUSY. If any part of the region falls outside of the valid address range for rm, it will return EINVAL. ENOMEM will be returned when rman_manage_region() failed to allocate memory for the region. The rman_init_from_resource() function is a wrapper routine to create a resource manager backed by an existing resource. It initializes rm us- ing rman_init() and then adds a region to rm corresponding to the ad- dress range allocated to r via rman_manage_region(). The rman_first_free_region() and rman_last_free_region() functions can be used to query a resource manager for its first (or last) unallocated region. If rm contains no free region, these functions will return ENOENT. Otherwise, *start and *end are set to the bounds of the free region and zero is returned. The rman_reserve_resource() 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, required 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 hap- pen. The alignment requirement (if any) is specified in flags. Often the RF_ALIGNMENT_LOG2 macro is used to specify alignment to a power- of-2 size, or rman_make_alignment_flags() can be used to compute the flags value at runtime. A shared segment will be allocated if the RF_SHAREABLE flag is set, otherwise an exclusive segment will be allo- cated. If this shared segment already exists, the caller has its de- vice added to the list of consumers. The rman_make_alignment_flags() function returns the flag mask corre- sponding to the desired alignment size. This should be used when call- ing rman_reserve_resource_bound(). The rman_is_region_manager() function returns true if the allocated re- source r was allocated from rm. Otherwise, it returns false. The rman_adjust_resource() function is used to adjust the reserved ad- dress range of an allocated resource to reserve start through end. It can be used to grow or shrink one or both ends of the resource range. The current implementation does not support entirely relocating the re- source and will fail with EINVAL if the new resource range does not overlap the old resource range. If either end of the resource range grows and the new resource range would conflict with another allocated resource, the function will fail with EBUSY. The rman_adjust_resource() function does not support adjusting the resource range for shared resources and will fail such attempts with EINVAL. Upon success, the resource r will have a start address of start and an end address of end and the function will return zero. Note that none of the constraints of the original allocation request such as alignment or boundary restrictions are checked by rman_adjust_resource(). It is the caller's responsibility to enforce any such requirements. 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_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 re- trieve 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_mapping() function is used to associate a resource mapping with a resource r. The mapping must cover the entire resource. Set- ting a mapping sets the associated bus_space(9) handle and tag for r as well as the kernel virtual address if the mapping contains one. These individual values can be retrieved via rman_get_bushandle(), rman_get_bustag(), and rman_get_virtual(). The rman_get_mapping() function can be used to retrieve the associated resource mapping 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_set_type() function associates a resource type with a resource r. The rman_get_type() function retrieves this type. The rman_get_device() function returns a pointer to the device which reserved the resource r. SEE ALSO bus_activate_resource(9), bus_adjust_resource(9), bus_alloc_resource(9), bus_map_resource(9), bus_release_resource(9), bus_set_resource(9), bus_space(9), mutex(9) AUTHORS This manual page was written by Bruce M Simpson <bms@spc.org>. FreeBSD 15.0 March 13, 2024 RMAN(9)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHORS
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