1 | /* |
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2 | * CORE Semaphore Handler |
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3 | * |
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4 | * DESCRIPTION: |
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5 | * |
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6 | * This package is the implementation of the CORE Semaphore Handler. |
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7 | * This core object utilizes standard Dijkstra counting semaphores to provide |
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8 | * synchronization and mutual exclusion capabilities. |
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9 | * |
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10 | * COPYRIGHT (c) 1989-1999. |
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11 | * On-Line Applications Research Corporation (OAR). |
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12 | * |
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13 | * The license and distribution terms for this file may be |
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14 | * found in the file LICENSE in this distribution or at |
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15 | * http://www.OARcorp.com/rtems/license.html. |
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16 | * |
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17 | * $Id$ |
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18 | */ |
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19 | |
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20 | #include <rtems/system.h> |
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21 | #include <rtems/score/isr.h> |
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22 | #include <rtems/score/coresem.h> |
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23 | #include <rtems/score/states.h> |
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24 | #include <rtems/score/thread.h> |
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25 | #include <rtems/score/threadq.h> |
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26 | #if defined(RTEMS_MULTIPROCESSING) |
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27 | #include <rtems/score/mpci.h> |
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28 | #endif |
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29 | |
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30 | /*PAGE |
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31 | * |
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32 | * _CORE_semaphore_Surrender |
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33 | * |
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34 | * Input parameters: |
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35 | * the_semaphore - the semaphore to be flushed |
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36 | * id - id of parent semaphore |
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37 | * api_semaphore_mp_support - api dependent MP support actions |
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38 | * |
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39 | * Output parameters: |
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40 | * CORE_SEMAPHORE_STATUS_SUCCESSFUL - if successful |
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41 | * core error code - if unsuccessful |
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42 | * |
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43 | * Output parameters: |
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44 | */ |
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45 | |
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46 | CORE_semaphore_Status _CORE_semaphore_Surrender( |
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47 | CORE_semaphore_Control *the_semaphore, |
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48 | Objects_Id id, |
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49 | CORE_semaphore_API_mp_support_callout api_semaphore_mp_support |
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50 | ) |
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51 | { |
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52 | Thread_Control *the_thread; |
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53 | ISR_Level level; |
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54 | CORE_semaphore_Status status; |
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55 | |
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56 | status = CORE_SEMAPHORE_STATUS_SUCCESSFUL; |
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57 | |
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58 | if ( (the_thread = _Thread_queue_Dequeue(&the_semaphore->Wait_queue)) ) { |
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59 | |
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60 | if ( !_Objects_Is_local_id( the_thread->Object.id ) ) |
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61 | (*api_semaphore_mp_support) ( the_thread, id ); |
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62 | |
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63 | } else { |
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64 | _ISR_Disable( level ); |
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65 | if ( the_semaphore->count < the_semaphore->Attributes.maximum_count ) |
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66 | the_semaphore->count += 1; |
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67 | else |
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68 | status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED; |
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69 | _ISR_Enable( level ); |
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70 | } |
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71 | |
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72 | return status; |
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73 | } |
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74 | |
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