From 9c191eea63fd6c5511c01186297722e594220032 Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Mon, 25 Sep 2006 13:36:58 +0000 Subject: * score/Makefile.am, score/preinstall.am, score/include/rtems/score/coresem.h, score/include/rtems/score/object.h, score/include/rtems/score/states.h, score/inline/rtems/score/coresem.inl: Add SuperCore Barriers, SpinLocks and a partial implementation of RWLocks. * score/include/rtems/score/corebarrier.h, score/include/rtems/score/corerwlock.h, score/include/rtems/score/corespinlock.h, score/inline/rtems/score/corebarrier.inl, score/inline/rtems/score/corerwlock.inl, score/inline/rtems/score/corespinlock.inl, score/macros/rtems/score/corebarrier.inl, score/macros/rtems/score/corerwlock.inl, score/macros/rtems/score/corespinlock.inl, score/src/corebarrier.c, score/src/corebarrierrelease.c, score/src/corebarrierwait.c, score/src/corerwlock.c, score/src/corerwlockobtainread.c, score/src/corerwlockobtainwrite.c, score/src/corerwlockrelease.c, score/src/corespinlock.c, score/src/corespinlockrelease.c, score/src/corespinlockwait.c: New files. --- cpukit/score/src/corerwlockobtainwrite.c | 93 ++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 cpukit/score/src/corerwlockobtainwrite.c (limited to 'cpukit/score/src/corerwlockobtainwrite.c') diff --git a/cpukit/score/src/corerwlockobtainwrite.c b/cpukit/score/src/corerwlockobtainwrite.c new file mode 100644 index 0000000000..02e7906249 --- /dev/null +++ b/cpukit/score/src/corerwlockobtainwrite.c @@ -0,0 +1,93 @@ +/* + * SuperCore RWLock Handler -- Obtain RWLock for writing + * + * COPYRIGHT (c) 1989-2006. + * 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. + * + * $Id$ + */ + +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include +#include +#include +#include +#include + +/*PAGE + * + * _CORE_rwlock_Obtain_for_writing + * + * This function waits for the rwlock to become available. Optionally, + * a limit may be placed on the duration of the spin. + * + * Input parameters: + * the_rwlock - the rwlock control block to initialize + * timeout_allowed - true if timeout allowed + * timeout - the maximum number of ticks to spin + * + * Output parameters: NONE + */ + +void _CORE_RWLock_Obtain_for_writing( + CORE_RWLock_Control *the_rwlock, + Objects_Id id, + boolean wait, + Watchdog_Interval timeout, + CORE_RWLock_API_mp_support_callout api_rwlock_mp_support +) +{ + ISR_Level level; + Thread_Control *executing = _Thread_Executing; + + /* + * If unlocked, then OK to read. + * Otherwise, we have to block. + * If locked for reading and no waiters, then OK to read. + * If any thread is waiting, then we wait. + */ + + _ISR_Disable( level ); + switch ( the_rwlock->current_state ) { + case CORE_RWLOCK_UNLOCKED: + the_rwlock->current_state = CORE_RWLOCK_LOCKED_FOR_WRITING; + _ISR_Enable( level ); + executing->Wait.return_code = CORE_RWLOCK_SUCCESSFUL; + return; + + case CORE_RWLOCK_LOCKED_FOR_READING: + case CORE_RWLOCK_LOCKED_FOR_WRITING: + break; + } + + /* + * If the thread is not willing to wait, then return immediately. + */ + + if ( !wait ) { + _ISR_Enable( level ); + executing->Wait.return_code = CORE_RWLOCK_UNAVAILABLE; + } + + /* + * We need to wait to enter this critical section + */ + + _Thread_queue_Enter_critical_section( &the_rwlock->Wait_queue ); + executing->Wait.queue = &the_rwlock->Wait_queue; + executing->Wait.id = id; + executing->Wait.option = CORE_RWLOCK_THREAD_WAITING_FOR_WRITE; + executing->Wait.return_code = CORE_RWLOCK_SUCCESSFUL; + _ISR_Enable( level ); + + _Thread_queue_Enqueue( &the_rwlock->Wait_queue, timeout ); + + /* return to API level so it can dispatch and we block */ +} -- cgit v1.2.3