1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Initialize a Core Mutex |
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5 | * @ingroup ScoreMutex |
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6 | */ |
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7 | |
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8 | /* |
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9 | * COPYRIGHT (c) 1989-1999. |
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10 | * On-Line Applications Research Corporation (OAR). |
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11 | * |
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12 | * The license and distribution terms for this file may be |
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13 | * found in the file LICENSE in this distribution or at |
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14 | * http://www.rtems.org/license/LICENSE. |
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15 | */ |
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16 | |
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17 | #if HAVE_CONFIG_H |
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18 | #include "config.h" |
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19 | #endif |
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20 | |
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21 | #include <rtems/system.h> |
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22 | #include <rtems/score/isr.h> |
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23 | #include <rtems/score/coremuteximpl.h> |
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24 | #include <rtems/score/thread.h> |
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25 | |
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26 | CORE_mutex_Status _CORE_mutex_Initialize( |
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27 | CORE_mutex_Control *the_mutex, |
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28 | Thread_Control *executing, |
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29 | const CORE_mutex_Attributes *the_mutex_attributes, |
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30 | bool initially_locked |
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31 | ) |
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32 | { |
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33 | |
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34 | /* Add this to the RTEMS environment later ????????? |
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35 | rtems_assert( initial_lock == CORE_MUTEX_LOCKED || |
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36 | initial_lock == CORE_MUTEX_UNLOCKED ); |
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37 | */ |
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38 | |
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39 | the_mutex->Attributes = *the_mutex_attributes; |
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40 | |
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41 | if ( initially_locked ) { |
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42 | bool is_priority_ceiling = |
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43 | _CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ); |
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44 | |
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45 | the_mutex->nest_count = 1; |
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46 | the_mutex->holder = executing; |
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47 | |
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48 | if ( is_priority_ceiling || |
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49 | _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) ) { |
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50 | Priority_Control ceiling = the_mutex->Attributes.priority_ceiling; |
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51 | |
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52 | /* |
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53 | * The mutex initialization is only protected by the allocator lock in |
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54 | * general. Disable thread dispatching before the priority check to |
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55 | * prevent interference with priority inheritance. |
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56 | */ |
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57 | _Thread_Disable_dispatch(); |
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58 | |
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59 | if ( is_priority_ceiling && executing->current_priority < ceiling ) { |
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60 | _Thread_Enable_dispatch(); |
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61 | return CORE_MUTEX_STATUS_CEILING_VIOLATED; |
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62 | } |
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63 | |
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64 | #ifdef __RTEMS_STRICT_ORDER_MUTEX__ |
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65 | _Chain_Prepend_unprotected( &executing->lock_mutex, |
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66 | &the_mutex->queue.lock_queue ); |
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67 | the_mutex->queue.priority_before = executing->current_priority; |
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68 | #endif |
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69 | |
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70 | executing->resource_count++; |
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71 | |
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72 | if ( is_priority_ceiling ) { |
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73 | _Thread_Change_priority( executing, ceiling, false ); |
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74 | } |
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75 | |
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76 | _Thread_Enable_dispatch(); |
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77 | } |
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78 | } else { |
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79 | the_mutex->nest_count = 0; |
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80 | the_mutex->holder = NULL; |
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81 | } |
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82 | |
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83 | _Thread_queue_Initialize( |
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84 | &the_mutex->Wait_queue, |
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85 | _CORE_mutex_Is_fifo( the_mutex_attributes ) ? |
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86 | THREAD_QUEUE_DISCIPLINE_FIFO : THREAD_QUEUE_DISCIPLINE_PRIORITY, |
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87 | STATES_WAITING_FOR_MUTEX, |
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88 | CORE_MUTEX_TIMEOUT |
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89 | ); |
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90 | |
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91 | return CORE_MUTEX_STATUS_SUCCESSFUL; |
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92 | } |
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