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Diffstat (limited to 'cpukit/score/src/coresem.c')
| -rw-r--r-- | cpukit/score/src/coresem.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/cpukit/score/src/coresem.c b/cpukit/score/src/coresem.c new file mode 100644 index 0000000000..e7e1705f3c --- /dev/null +++ b/cpukit/score/src/coresem.c @@ -0,0 +1,185 @@ +/* + * CORE Semaphore Handler + * + * DESCRIPTION: + * + * This package is the implementation of the CORE Semaphore Handler. + * This core object utilizes standard Dijkstra counting semaphores to provide + * synchronization and mutual exclusion capabilities. + * + * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. + * On-Line Applications Research Corporation (OAR). + * All rights assigned to U.S. Government, 1994. + * + * This material may be reproduced by or for the U.S. Government pursuant + * to the copyright license under the clause at DFARS 252.227-7013. This + * notice must appear in all copies of this file and its derivatives. + * + * $Id$ + */ + +#include <rtems/system.h> +#include <rtems/core/isr.h> +#include <rtems/core/coresem.h> +#include <rtems/core/states.h> +#include <rtems/core/thread.h> +#include <rtems/core/threadq.h> +#include <rtems/core/mpci.h> + +/*PAGE + * + * CORE_semaphore_Initialize + * + * This function initialize a semaphore and sets the initial value based + * on the given count. + * + * Input parameters: + * the_semaphore - the semaphore control block to initialize + * the_class - the API class of the object + * the_semaphore_attributes - the attributes specified at create time + * initial_value - semaphore's initial value + * proxy_extract_callout - MP specific extract callout + * + * Output parameters: NONE + */ + +void _CORE_semaphore_Initialize( + CORE_semaphore_Control *the_semaphore, + Objects_Classes the_class, + CORE_semaphore_Attributes *the_semaphore_attributes, + unsigned32 initial_value, + Thread_queue_Extract_callout proxy_extract_callout +) +{ + + the_semaphore->Attributes = *the_semaphore_attributes; + the_semaphore->count = initial_value; + + _Thread_queue_Initialize( + &the_semaphore->Wait_queue, + the_class, + _CORE_semaphore_Is_priority( the_semaphore_attributes ) ? + THREAD_QUEUE_DISCIPLINE_PRIORITY : THREAD_QUEUE_DISCIPLINE_FIFO, + STATES_WAITING_FOR_SEMAPHORE, + proxy_extract_callout, + CORE_SEMAPHORE_TIMEOUT + ); +} + +/*PAGE + * + * _CORE_semaphore_Surrender + * + * Input parameters: + * the_semaphore - the semaphore to be flushed + * id - id of parent semaphore + * api_semaphore_mp_support - api dependent MP support actions + * + * Output parameters: + * CORE_SEMAPHORE_STATUS_SUCCESSFUL - if successful + * core error code - if unsuccessful + * + * Output parameters: + */ + +CORE_semaphore_Status _CORE_semaphore_Surrender( + CORE_semaphore_Control *the_semaphore, + Objects_Id id, + CORE_semaphore_API_mp_support_callout api_semaphore_mp_support +) +{ + Thread_Control *the_thread; + + if ( (the_thread = _Thread_queue_Dequeue(&the_semaphore->Wait_queue)) ) { + + if ( !_Objects_Is_local_id( the_thread->Object.id ) ) + (*api_semaphore_mp_support) ( the_thread, id ); + + } else + the_semaphore->count += 1; + + return( CORE_SEMAPHORE_STATUS_SUCCESSFUL ); +} + +/*PAGE + * + * _CORE_semaphore_Seize + * + * This routine attempts to allocate a core semaphore to the calling thread. + * + * Input parameters: + * the_semaphore - pointer to semaphore control block + * id - id of object to wait on + * wait - TRUE if wait is allowed, FALSE otherwise + * timeout - number of ticks to wait (0 means forever) + * + * Output parameters: NONE + * + * INTERRUPT LATENCY: + * available + * wait + */ + +void _CORE_semaphore_Seize( + CORE_semaphore_Control *the_semaphore, + Objects_Id id, + boolean wait, + Watchdog_Interval timeout +) +{ + Thread_Control *executing; + ISR_Level level; + + executing = _Thread_Executing; + executing->Wait.return_code = CORE_SEMAPHORE_STATUS_SUCCESSFUL; + _ISR_Disable( level ); + if ( the_semaphore->count != 0 ) { + the_semaphore->count -= 1; + executing->resource_count++; + _ISR_Enable( level ); + return; + } + + if ( !wait ) { + _ISR_Enable( level ); + executing->Wait.return_code = CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT; + return; + } + + the_semaphore->Wait_queue.sync = TRUE; + executing->Wait.queue = &the_semaphore->Wait_queue; + executing->Wait.id = id; + _ISR_Enable( level ); + + _Thread_queue_Enqueue( &the_semaphore->Wait_queue, timeout ); +} + + +/*PAGE + * + * _CORE_semaphore_Flush + * + * This function a flushes the semaphore's task wait queue. + * + * Input parameters: + * the_semaphore - the semaphore to be flushed + * remote_extract_callout - function to invoke remotely + * status - status to pass to thread + * + * Output parameters: NONE + */ + +void _CORE_semaphore_Flush( + CORE_semaphore_Control *the_semaphore, + Thread_queue_Flush_callout remote_extract_callout, + unsigned32 status +) +{ + + _Thread_queue_Flush( + &the_semaphore->Wait_queue, + remote_extract_callout, + status + ); + +} |