Man page 9 : allocate_resource

allocate_resource - allocate empty slot in the resource tree given range & alignment. The resource will be reallocated with a new size if it was already allocated

int allocate_resource(struct resource *  root , struct resource *  new , resource_size_t  size , resource_size_t  min , resource_size_t  max , resource_size_t  align , resource_size_t (* alignf ) (void *, const struct resource *, resource_size_t, resource_size_t), void *  alignf_data );

root
    root resource descriptor

new
    resource descriptor desired by caller

size
    requested resource region size

min
    minimum boundary to allocate

max
    maximum boundary to allocate

align
    alignment requested, in bytes

alignf
    alignment function, optional, called if not NULL

alignf_data
    arbitrary data to pass to the alignf function