[8fcafdd5] | 1 | /* |
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| 2 | * Copyright (c) 2014 embedded brains GmbH. All rights reserved. |
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| 3 | * |
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| 4 | * embedded brains GmbH |
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| 5 | * Dornierstr. 4 |
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| 6 | * 82178 Puchheim |
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| 7 | * Germany |
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| 8 | * <rtems@embedded-brains.de> |
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| 9 | * |
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| 10 | * The license and distribution terms for this file may be |
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| 11 | * found in the file LICENSE in this distribution or at |
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| 12 | * http://www.rtems.org/license/LICENSE. |
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| 13 | */ |
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| 14 | |
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| 15 | #ifndef _RTEMS_SCORE_MRSP_H |
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| 16 | #define _RTEMS_SCORE_MRSP_H |
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| 17 | |
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| 18 | #include <rtems/score/cpuopts.h> |
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| 19 | |
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| 20 | #if defined(RTEMS_SMP) |
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| 21 | |
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| 22 | #include <rtems/score/chain.h> |
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[864d3475] | 23 | #include <rtems/score/scheduler.h> |
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[8fcafdd5] | 24 | #include <rtems/score/thread.h> |
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| 25 | |
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| 26 | #ifdef __cplusplus |
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| 27 | extern "C" { |
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| 28 | #endif /* __cplusplus */ |
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| 29 | |
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| 30 | /** |
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| 31 | * @defgroup ScoreMRSP Multiprocessor Resource Sharing Protocol Handler |
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| 32 | * |
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| 33 | * @ingroup Score |
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| 34 | * |
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| 35 | * @brief Multiprocessor Resource Sharing Protocol (MrsP). |
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| 36 | * |
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| 37 | * The Multiprocessor Resource Sharing Protocol (MrsP) is defined in A. Burns |
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| 38 | * and A.J. Wellings, A Schedulability Compatible Multiprocessor Resource |
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| 39 | * Sharing Protocol - MrsP, Proceedings of the 25th Euromicro Conference on |
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| 40 | * Real-Time Systems (ECRTS 2013), July 2013. It is a generalization of the |
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| 41 | * Priority Ceiling Protocol to SMP systems. Each MrsP semaphore uses a |
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| 42 | * ceiling priority per scheduler instance. A task obtaining or owning a MrsP |
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| 43 | * semaphore will execute with the ceiling priority for its scheduler instance |
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| 44 | * as specified by the MrsP semaphore object. Tasks waiting to get ownership |
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| 45 | * of a MrsP semaphore will not relinquish the processor voluntarily. In case |
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| 46 | * the owner of a MrsP semaphore gets preempted it can ask all tasks waiting |
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| 47 | * for this semaphore to help out and temporarily borrow the right to execute |
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| 48 | * on one of their assigned processors. |
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| 49 | * |
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| 50 | * @{ |
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| 51 | */ |
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| 52 | |
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| 53 | /** |
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| 54 | * @brief MrsP status code. |
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| 55 | * |
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| 56 | * The values are chosen to directly map to RTEMS status codes. In case this |
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| 57 | * implementation is used for other APIs, then for example the errno values can |
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| 58 | * be added with a bit shift. |
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| 59 | */ |
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| 60 | typedef enum { |
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| 61 | MRSP_SUCCESSFUL = 0, |
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| 62 | MRSP_TIMEOUT = 6, |
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| 63 | MRSP_INVALID_NUMBER = 10, |
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| 64 | MRSP_RESOUCE_IN_USE = 12, |
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| 65 | MRSP_UNSATISFIED = 13, |
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[9553e7a6] | 66 | MRSP_INCORRECT_STATE = 14, |
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[8fcafdd5] | 67 | MRSP_INVALID_PRIORITY = 19, |
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| 68 | MRSP_NOT_OWNER_OF_RESOURCE = 23, |
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[864d3475] | 69 | MRSP_NO_MEMORY = 26, |
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| 70 | |
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| 71 | /** |
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| 72 | * @brief Internal state used for MRSP_Rival::status to indicate that this |
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| 73 | * rival waits for resource ownership. |
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| 74 | */ |
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| 75 | MRSP_WAIT_FOR_OWNERSHIP = 255 |
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[8fcafdd5] | 76 | } MRSP_Status; |
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| 77 | |
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| 78 | /** |
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| 79 | * @brief MrsP rival. |
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| 80 | * |
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| 81 | * The rivals are used by threads waiting for resource ownership. They are |
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| 82 | * registered in the MRSP control block. |
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| 83 | */ |
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| 84 | typedef struct { |
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| 85 | /** |
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| 86 | * @brief The node for registration in the MRSP rival chain. |
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| 87 | * |
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[864d3475] | 88 | * The chain operations are protected by the Giant lock and disabled |
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| 89 | * interrupts. |
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| 90 | * |
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[8fcafdd5] | 91 | * @see MRSP_Control::Rivals. |
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| 92 | */ |
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| 93 | Chain_Node Node; |
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| 94 | |
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| 95 | /** |
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| 96 | * @brief Identification of the rival thread. |
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| 97 | */ |
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| 98 | Thread_Control *thread; |
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| 99 | |
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| 100 | /** |
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[864d3475] | 101 | * @brief The initial priority of the thread at the begin of the resource |
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| 102 | * obtain sequence. |
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| 103 | * |
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| 104 | * Used to restore the priority after a release of this resource or timeout. |
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| 105 | */ |
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| 106 | Priority_Control initial_priority; |
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| 107 | |
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| 108 | /** |
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| 109 | * @brief The initial help state of the thread at the begin of the resource |
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| 110 | * obtain sequence. |
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| 111 | * |
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| 112 | * Used to restore this state after a timeout. |
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| 113 | */ |
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| 114 | Scheduler_Help_state initial_help_state; |
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| 115 | |
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| 116 | /** |
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| 117 | * @brief The rival status. |
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[8fcafdd5] | 118 | * |
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[864d3475] | 119 | * Initially the status is set to MRSP_WAIT_FOR_OWNERSHIP. The rival will |
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| 120 | * busy wait until a status change happens. This can be MRSP_SUCCESSFUL or |
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| 121 | * MRSP_TIMEOUT. State changes are protected by the Giant lock and disabled |
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| 122 | * interrupts. |
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[8fcafdd5] | 123 | */ |
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[864d3475] | 124 | volatile MRSP_Status status; |
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[8fcafdd5] | 125 | } MRSP_Rival; |
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| 126 | |
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| 127 | /** |
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| 128 | * @brief MrsP control block. |
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| 129 | */ |
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| 130 | typedef struct { |
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| 131 | /** |
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[9553e7a6] | 132 | * @brief Basic resource control. |
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[8fcafdd5] | 133 | */ |
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[9553e7a6] | 134 | Resource_Control Resource; |
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[8fcafdd5] | 135 | |
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| 136 | /** |
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| 137 | * @brief A chain of MrsP rivals waiting for resource ownership. |
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| 138 | * |
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| 139 | * @see MRSP_Rival::Node. |
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| 140 | */ |
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| 141 | Chain_Control Rivals; |
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| 142 | |
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[9553e7a6] | 143 | /** |
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| 144 | * @brief The initial priority of the owner before it was elevated to the |
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| 145 | * ceiling priority. |
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| 146 | */ |
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| 147 | Priority_Control initial_priority_of_owner; |
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| 148 | |
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[8fcafdd5] | 149 | /** |
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| 150 | * @brief One ceiling priority per scheduler instance. |
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| 151 | */ |
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| 152 | Priority_Control *ceiling_priorities; |
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| 153 | } MRSP_Control; |
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| 154 | |
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| 155 | /** @} */ |
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| 156 | |
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| 157 | #ifdef __cplusplus |
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| 158 | } |
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| 159 | #endif /* __cplusplus */ |
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| 160 | |
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| 161 | #endif /* RTEMS_SMP */ |
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| 162 | |
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| 163 | #endif /* _RTEMS_SCORE_MRSP_H */ |
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