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Diffstat (limited to 'cpukit/score/include/rtems/score/corerwlock.h')
| -rw-r--r-- | cpukit/score/include/rtems/score/corerwlock.h | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/cpukit/score/include/rtems/score/corerwlock.h b/cpukit/score/include/rtems/score/corerwlock.h new file mode 100644 index 0000000000..f97e4679b8 --- /dev/null +++ b/cpukit/score/include/rtems/score/corerwlock.h @@ -0,0 +1,235 @@ +/** + * @file rtems/score/corerwlock.h + * + * This include file contains all the constants and structures associated + * with the RWLock Handler. + */ + +/* + * 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_CORERWLOCK_H +#define _RTEMS_SCORE_CORERWLOCK_H + +/** + * @defgroup ScoreRWLock RWLock Handler + * + * This handler encapsulates functionality which provides the foundation + * RWLock services used in all of the APIs supported by RTEMS. + */ +/**@{*/ + +#ifdef __cplusplus +extern "C" { +#endif + +#include <rtems/score/thread.h> +#include <rtems/score/threadq.h> +#include <rtems/score/priority.h> +#include <rtems/score/watchdog.h> + +/** + * The following type defines the callout which the API provides + * to support global/multiprocessor operations on RWLocks. + */ +typedef void ( *CORE_RWLock_API_mp_support_callout )( + Thread_Control *, + Objects_Id + ); + +/** + * RWLock State. + */ +typedef enum { + /** This indicates the the RWLock is not currently locked. + */ + CORE_RWLOCK_UNLOCKED, + /** This indicates the the RWLock is currently locked for reading. + */ + CORE_RWLOCK_LOCKED_FOR_READING, + /** This indicates the the RWLock is currently locked for reading. + */ + CORE_RWLOCK_LOCKED_FOR_WRITING +} CORE_RWLock_States; + +/** + * Core RWLock handler return statuses. + */ +typedef enum { + /** This status indicates that the operation completed successfully. */ + CORE_RWLOCK_SUCCESSFUL, + /** This status indicates that the thread was blocked waiting for an */ + CORE_RWLOCK_WAS_DELETED, + /** This status indicates that the rwlock was not immediately available. */ + CORE_RWLOCK_UNAVAILABLE, + /** 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_RWLOCK_TIMEOUT +} CORE_RWLock_Status; + +/** This is the last status value. + */ +#define CORE_RWLOCK_STATUS_LAST CORE_RWLOCK_TIMEOUT + +/** + * This is used to denote that a thread is blocking waiting for + * read-only access to the RWLock. + */ +#define CORE_RWLOCK_THREAD_WAITING_FOR_READ 0 + +/** + * This is used to denote that a thread is blocking waiting for + * write-exclusive access to the RWLock. + */ +#define CORE_RWLOCK_THREAD_WAITING_FOR_WRITE 1 + +/** + * The following defines the control block used to manage the + * attributes of each RWLock. + */ +typedef struct { + /** This field indicates XXX. + */ + int XXX; +} CORE_RWLock_Attributes; + +/** + * The following defines the control block used to manage each + * RWLock. + */ +typedef struct { + /** This field is the Waiting Queue used to manage the set of tasks + * which are blocked waiting for the RWLock to be released. + */ + Thread_queue_Control Wait_queue; + /** This element is the set of attributes which define this instance's + * behavior. + */ + CORE_RWLock_Attributes Attributes; + /** This element is the current state of the RWLock. + */ + CORE_RWLock_States current_state; + /** This element contains the current number of thread waiting for this + * RWLock to be released. */ + uint32_t number_of_readers; +} CORE_RWLock_Control; + +/** + * This routine initializes the RWLock based on the parameters passed. + * + * @param[in] the_rwlock is the RWLock to initialize + * @param[in] the_rwlock_attributes define the behavior of this instance + */ +void _CORE_RWLock_Initialize( + CORE_RWLock_Control *the_rwlock, + CORE_RWLock_Attributes *the_rwlock_attributes +); + +/** + * This routine attempts to obtain the RWLock for read access. + * + * @param[in] the_rwlock is the RWLock to wait for + * @param[in] id is the id of the object being waited upon + * @param[in] wait is true if the calling thread is willing to wait + * @param[in] timeout is the number of ticks the calling thread is willing + * to wait if @a wait is true. + * @param[in] api_rwlock_mp_support is the routine to invoke if the + * thread unblocked is remote + * + * @note Status is returned via the thread control block. + */ +void _CORE_RWLock_Obtain_for_reading( + CORE_RWLock_Control *the_rwlock, + Objects_Id id, + bool wait, + Watchdog_Interval timeout, + CORE_RWLock_API_mp_support_callout api_rwlock_mp_support +); + +/** + * This routine attempts to obtain the RWLock for write exclusive access. + * + * @param[in] the_rwlock is the RWLock to wait for + * @param[in] id is the id of the object being waited upon + * @param[in] wait is true if the calling thread is willing to wait + * @param[in] timeout is the number of ticks the calling thread is willing + * to wait if @a wait is true. + * @param[in] api_rwlock_mp_support is the routine to invoke if the + * thread unblocked is remote + * + * @note Status is returned via the thread control block. + */ +void _CORE_RWLock_Obtain_for_writing( + CORE_RWLock_Control *the_rwlock, + Objects_Id id, + bool wait, + Watchdog_Interval timeout, + CORE_RWLock_API_mp_support_callout api_rwlock_mp_support +); + +/** + * This routine manually releases the RWLock. All of the threads waiting + * for the RWLock will be readied. + * + * @param[in] the_rwlock is the RWLock to surrender + * + * @return Status is returned to indicate successful or failure. + */ +CORE_RWLock_Status _CORE_RWLock_Release( + CORE_RWLock_Control *the_rwlock +); + +/** + * This routine assists in the deletion of a RWLock by flushing the + * associated wait queue. + * + * @param[in] _the_rwlock is the RWLock 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 + */ +#define _CORE_RWLock_Flush( _the_rwlock, _remote_extract_callout, _status) \ + _Thread_queue_Flush( \ + &((_the_rwlock)->Wait_queue), \ + (_remote_extract_callout), \ + (_status) \ + ) + +/** + * @brief RWLock Specific Thread Queue Timeout + * + * This routine processes a thread which timeouts while waiting on + * an RWLock's thread queue. It is called by the watchdog handler. + * + * @param[in] id is the Id of thread to timeout + * @param[in] ignored is an unused pointer to a caller defined area + */ + +void _CORE_RWLock_Timeout( + Objects_Id id, + void *ignored +); + + +#ifndef __RTEMS_APPLICATION__ +#include <rtems/score/corerwlock.inl> +#endif + +#ifdef __cplusplus +} +#endif + +/**@}*/ + +#endif +/* end of include file */ |