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Diffstat (limited to 'cpukit/score/include/rtems/score/coresem.h')
| -rw-r--r-- | cpukit/score/include/rtems/score/coresem.h | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/cpukit/score/include/rtems/score/coresem.h b/cpukit/score/include/rtems/score/coresem.h new file mode 100644 index 0000000000..cf89e629d7 --- /dev/null +++ b/cpukit/score/include/rtems/score/coresem.h @@ -0,0 +1,209 @@ +/** + * @file rtems/score/coresem.h + * + * This include file contains all the constants and structures associated + * with the Counting Semaphore Handler. A counting semaphore is the + * standard Dijkstra binary semaphore used to provide synchronization + * and mutual exclusion capabilities. + */ + +/* + * COPYRIGHT (c) 1989-2008. + * 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.rtems.com/license/LICENSE. + * + * $Id$ + */ + +#ifndef _RTEMS_SCORE_CORESEM_H +#define _RTEMS_SCORE_CORESEM_H + +/** + * @defgroup ScoreSemaphore Semaphore Handler + * + * This handler encapsulates functionality which provides the foundation + * Semaphore services used in all of the APIs supported by RTEMS. + */ +/**@{*/ + +#include <rtems/score/thread.h> +#include <rtems/score/threadq.h> +#include <rtems/score/priority.h> +#include <rtems/score/watchdog.h> + +#ifdef __cplusplus +extern "C" { +#endif + +#if defined(RTEMS_POSIX_API) + #define RTEMS_SCORE_CORESEM_ENABLE_SEIZE_BODY +#endif + +/** + * The following type defines the callout which the API provides + * to support global/multiprocessor operations on semaphores. + */ +typedef void ( *CORE_semaphore_API_mp_support_callout )( + Thread_Control *, + Objects_Id + ); + +/** + * Blocking disciplines for a semaphore. + */ +typedef enum { + /** This specifies that threads will wait for the semaphore in FIFO order. */ + CORE_SEMAPHORE_DISCIPLINES_FIFO, + /** This specifies that threads will wait for the semaphore in + * priority order. + */ + CORE_SEMAPHORE_DISCIPLINES_PRIORITY +} CORE_semaphore_Disciplines; + +/** + * Core Semaphore handler return statuses. + */ +typedef enum { + /** This status indicates that the operation completed successfully. */ + CORE_SEMAPHORE_STATUS_SUCCESSFUL, + /** This status indicates that the calling task did not want to block + * and the operation was unable to complete immediately because the + * resource was unavailable. + */ + CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT, + /** This status indicates that the thread was blocked waiting for an + * operation to complete and the semaphore was deleted. + */ + CORE_SEMAPHORE_WAS_DELETED, + /** This status indicates that the calling task was willing to block + * but the operation was unable to complete within the time allotted + * because the resource never became available. + */ + CORE_SEMAPHORE_TIMEOUT, + /** This status indicates that an attempt was made to unlock the semaphore + * and this would have made its count greater than that allowed. + */ + CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED +} CORE_semaphore_Status; + +/** + * @brief Core Semaphore Last Status + * + * This is the last status value. + */ +#define CORE_SEMAPHORE_STATUS_LAST CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED + +/** + * The following defines the control block used to manage the + * attributes of each semaphore. + */ +typedef struct { + /** This element indicates the maximum count this semaphore may have. */ + uint32_t maximum_count; + /** This field indicates whether threads waiting on the semaphore block in + * FIFO or priority order. + */ + CORE_semaphore_Disciplines discipline; +} CORE_semaphore_Attributes; + +/** + * The following defines the control block used to manage each + * counting semaphore. + */ +typedef struct { + /** This field is the Waiting Queue used to manage the set of tasks + * which are blocked waiting to obtain the semaphore. + */ + Thread_queue_Control Wait_queue; + /** This element is the set of attributes which define this instance's + * behavior. + */ + CORE_semaphore_Attributes Attributes; + /** This element contains the current count of this semaphore. */ + uint32_t count; +} CORE_semaphore_Control; + +/** + * This routine initializes the semaphore based on the parameters passed. + * + * @param[in] the_semaphore is the semaphore to initialize + * @param[in] the_semaphore_attributes define the behavior of this instance + * @param[in] initial_value is the initial count of the semaphore + */ +void _CORE_semaphore_Initialize( + CORE_semaphore_Control *the_semaphore, + CORE_semaphore_Attributes *the_semaphore_attributes, + uint32_t initial_value +); + +#if defined(RTEMS_SCORE_CORESEM_ENABLE_SEIZE_BODY) + /** + * This routine attempts to receive a unit from @a the_semaphore. + * If a unit is available or if the wait flag is false, then the routine + * returns. Otherwise, the calling task is blocked until a unit becomes + * available. + * + * @param[in] the_semaphore is the semaphore to seize + * @param[in] id is the Id of the API level Semaphore object associated + * with this instance of a SuperCore Semaphore + * @param[in] wait indicates if the caller is willing to block + * @param[in] timeout is the number of ticks the calling thread is willing + * to wait if @a wait is true. + */ + void _CORE_semaphore_Seize( + CORE_semaphore_Control *the_semaphore, + Objects_Id id, + bool wait, + Watchdog_Interval timeout + ); +#endif + +/** + * This routine frees a unit to the semaphore. If a task was blocked waiting + * for a unit from this semaphore, then that task will be readied and the unit + * given to that task. Otherwise, the unit will be returned to the semaphore. + * + * @param[in] the_semaphore is the semaphore to surrender + * @param[in] id is the Id of the API level Semaphore object associated + * with this instance of a SuperCore Semaphore + * @param[in] api_semaphore_mp_support is the routine to invoke if the + * thread unblocked is remote + * + * @return an indication of whether the routine succeeded or failed + */ +CORE_semaphore_Status _CORE_semaphore_Surrender( + CORE_semaphore_Control *the_semaphore, + Objects_Id id, + CORE_semaphore_API_mp_support_callout api_semaphore_mp_support +); + +/** + * This routine assists in the deletion of a semaphore by flushing the + * associated wait queue. + * + * @param[in] the_semaphore is the semaphore to flush + * @param[in] remote_extract_callout is the routine to invoke if the + * thread unblocked is remote + * @param[in] status is the status to be returned to the unblocked thread + */ +void _CORE_semaphore_Flush( + CORE_semaphore_Control *the_semaphore, + Thread_queue_Flush_callout remote_extract_callout, + uint32_t status +); + +#ifndef __RTEMS_APPLICATION__ +#include <rtems/score/coresem.inl> +#endif + +#ifdef __cplusplus +} +#endif + +/**@}*/ + +#endif +/* end of include file */ |