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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [exec/] [rtems/] [src/] [semcreate.c] - Rev 846
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/* * Semaphore Manager * * DESCRIPTION: * * This package is the implementation of the Semaphore Manager. * This manager utilizes standard Dijkstra counting semaphores to provide * synchronization and mutual exclusion capabilities. * * Directives provided are: * * + create a semaphore * + get an ID of a semaphore * + delete a semaphore * + acquire a semaphore * + release a semaphore * * COPYRIGHT (c) 1989-1999. * On-Line Applications Research Corporation (OAR). * * The license and distribution terms for this file may be * found in the file LICENSE in this distribution or at * http://www.OARcorp.com/rtems/license.html. * * $Id: semcreate.c,v 1.2 2001-09-27 11:59:19 chris Exp $ */ #include <rtems/system.h> #include <rtems/rtems/status.h> #include <rtems/rtems/support.h> #include <rtems/rtems/attr.h> #include <rtems/score/isr.h> #include <rtems/score/object.h> #include <rtems/rtems/options.h> #include <rtems/rtems/sem.h> #include <rtems/score/coremutex.h> #include <rtems/score/coresem.h> #include <rtems/score/states.h> #include <rtems/score/thread.h> #include <rtems/score/threadq.h> #if defined(RTEMS_MULTIPROCESSING) #include <rtems/score/mpci.h> #endif #include <rtems/score/sysstate.h> #include <rtems/score/interr.h> /*PAGE * * rtems_semaphore_create * * This directive creates a semaphore and sets the initial value based * on the given count. A semaphore id is returned. * * Input parameters: * name - user defined semaphore name * count - initial count of semaphore * attribute_set - semaphore attributes * priority_ceiling - semaphore's ceiling priority * id - pointer to semaphore id * * Output parameters: * id - semaphore id * RTEMS_SUCCESSFUL - if successful * error code - if unsuccessful */ rtems_status_code rtems_semaphore_create( rtems_name name, unsigned32 count, rtems_attribute attribute_set, rtems_task_priority priority_ceiling, Objects_Id *id ) { register Semaphore_Control *the_semaphore; CORE_mutex_Attributes the_mutex_attributes; CORE_semaphore_Attributes the_semaphore_attributes; unsigned32 lock; if ( !rtems_is_name_valid( name ) ) return RTEMS_INVALID_NAME; #if defined(RTEMS_MULTIPROCESSING) if ( _Attributes_Is_global( attribute_set ) ) { if ( !_System_state_Is_multiprocessing ) return RTEMS_MP_NOT_CONFIGURED; if ( _Attributes_Is_inherit_priority( attribute_set ) ) return RTEMS_NOT_DEFINED; } else #endif if ( _Attributes_Is_inherit_priority( attribute_set ) || _Attributes_Is_priority_ceiling( attribute_set ) ) { if ( ! ( (_Attributes_Is_binary_semaphore( attribute_set ) || _Attributes_Is_simple_binary_semaphore( attribute_set )) && _Attributes_Is_priority( attribute_set ) ) ) return RTEMS_NOT_DEFINED; } if ( !_Attributes_Is_counting_semaphore( attribute_set ) && ( count > 1 ) ) return RTEMS_INVALID_NUMBER; _Thread_Disable_dispatch(); /* prevents deletion */ the_semaphore = _Semaphore_Allocate(); if ( !the_semaphore ) { _Thread_Enable_dispatch(); return RTEMS_TOO_MANY; } #if defined(RTEMS_MULTIPROCESSING) if ( _Attributes_Is_global( attribute_set ) && ! ( _Objects_MP_Allocate_and_open( &_Semaphore_Information, name, the_semaphore->Object.id, FALSE ) ) ) { _Semaphore_Free( the_semaphore ); _Thread_Enable_dispatch(); return RTEMS_TOO_MANY; } #endif the_semaphore->attribute_set = attribute_set; /* * If it is not a counting semaphore, then it is either a * simple binary semaphore or a more powerful mutex style binary * semaphore. */ if ( !_Attributes_Is_counting_semaphore( attribute_set ) ) { if ( _Attributes_Is_inherit_priority( attribute_set ) ) the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT; else if ( _Attributes_Is_priority_ceiling( attribute_set ) ) the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING; else if ( _Attributes_Is_priority( attribute_set ) ) the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY; else the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_FIFO; if ( _Attributes_Is_binary_semaphore( attribute_set ) ) { the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES; switch ( the_mutex_attributes.discipline ) { case CORE_MUTEX_DISCIPLINES_FIFO: case CORE_MUTEX_DISCIPLINES_PRIORITY: the_mutex_attributes.only_owner_release = FALSE; break; case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING: case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT: the_mutex_attributes.only_owner_release = TRUE; break; } } else { the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_BLOCKS; the_mutex_attributes.only_owner_release = FALSE; } the_mutex_attributes.priority_ceiling = priority_ceiling; if ( count == 1 ) lock = CORE_MUTEX_UNLOCKED; else lock = CORE_MUTEX_LOCKED; _CORE_mutex_Initialize( &the_semaphore->Core_control.mutex, OBJECTS_RTEMS_SEMAPHORES, &the_mutex_attributes, lock, #if defined(RTEMS_MULTIPROCESSING) _Semaphore_MP_Send_extract_proxy #else NULL #endif ); } else { if ( _Attributes_Is_priority( attribute_set ) ) the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_PRIORITY; else the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_FIFO; /* * This effectively disables limit checking. */ the_semaphore_attributes.maximum_count = 0xFFFFFFFF; /* * The following are just to make Purify happy. */ the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES; the_mutex_attributes.priority_ceiling = PRIORITY_MINIMUM; _CORE_semaphore_Initialize( &the_semaphore->Core_control.semaphore, OBJECTS_RTEMS_SEMAPHORES, &the_semaphore_attributes, count, #if defined(RTEMS_MULTIPROCESSING) _Semaphore_MP_Send_extract_proxy #else NULL #endif ); } _Objects_Open( &_Semaphore_Information, &the_semaphore->Object, &name ); *id = the_semaphore->Object.id; #if defined(RTEMS_MULTIPROCESSING) if ( _Attributes_Is_global( attribute_set ) ) _Semaphore_MP_Send_process_packet( SEMAPHORE_MP_ANNOUNCE_CREATE, the_semaphore->Object.id, name, 0 /* Not used */ ); #endif _Thread_Enable_dispatch(); return RTEMS_SUCCESSFUL; }
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