[e358088] | 1 | /** |
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| 2 | * @file |
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| 3 | * |
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| 4 | * @ingroup ScoreSMPLockCPU |
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| 5 | * |
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| 6 | * @brief CPU SMP Lock Implementation |
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| 7 | */ |
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| 8 | |
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| 9 | /* |
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| 10 | * Copyright (c) 2013 embedded brains GmbH |
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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.com/license/LICENSE. |
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| 15 | */ |
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| 16 | |
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| 17 | #ifndef _RTEMS_SCORE_NO_CPU_SMPLOCK_H |
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| 18 | #define _RTEMS_SCORE_NO_CPU_SMPLOCK_H |
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| 19 | |
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| 20 | #include <rtems/score/cpu.h> |
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| 21 | |
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| 22 | #ifdef __cplusplus |
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| 23 | extern "C" { |
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| 24 | #endif /* __cplusplus */ |
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| 25 | |
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| 26 | /** |
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| 27 | * @defgroup ScoreSMPLockCPU CPU SMP Locks |
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| 28 | * |
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| 29 | * @ingroup ScoreSMPLock |
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| 30 | * |
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| 31 | * This example will implement a ticket lock. |
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| 32 | * |
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| 33 | * @{ |
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| 34 | */ |
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| 35 | |
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| 36 | /** |
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| 37 | * @brief CPU SMP lock control. |
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| 38 | */ |
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| 39 | typedef struct { |
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| 40 | unsigned int next_ticket; |
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| 41 | unsigned int now_serving; |
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| 42 | } CPU_SMP_lock_Control; |
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| 43 | |
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| 44 | /** |
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| 45 | * @brief CPU SMP lock control initializer for static initialization. |
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| 46 | */ |
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| 47 | #define CPU_SMP_LOCK_INITIALIZER { 0, 0 } |
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| 48 | |
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| 49 | /** |
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| 50 | * @brief Initializes a CPU SMP lock control. |
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| 51 | * |
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| 52 | * @param[out] lock The CPU SMP lock control. |
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| 53 | */ |
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| 54 | static inline void _CPU_SMP_lock_Initialize( CPU_SMP_lock_Control *lock ) |
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| 55 | { |
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| 56 | lock->next_ticket = 0; |
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| 57 | lock->now_serving = 0; |
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| 58 | } |
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| 59 | |
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| 60 | /** |
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| 61 | * @brief Acquires a CPU SMP lock. |
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| 62 | * |
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[961669d] | 63 | * @param[in,out] lock The CPU SMP lock control. |
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[e358088] | 64 | */ |
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| 65 | static inline void _CPU_SMP_lock_Acquire( CPU_SMP_lock_Control *lock ) |
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| 66 | { |
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[4402308b] | 67 | #if 0 |
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[e358088] | 68 | unsigned int my_ticket = _Atomic_Fetch_and_increment( &lock->next_ticket ); |
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| 69 | |
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| 70 | while ( _Atomic_Load_and_acquire( &lock->now_serving ) != my_ticket ) { |
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| 71 | _Wait_some_time(); |
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| 72 | } |
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[4402308b] | 73 | #endif |
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[e358088] | 74 | } |
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| 75 | |
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| 76 | /** |
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| 77 | * @brief Releases a CPU SMP lock. |
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| 78 | * |
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[961669d] | 79 | * @param[in,out] lock The CPU SMP lock control. |
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[e358088] | 80 | */ |
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| 81 | static inline void _CPU_SMP_lock_Release( CPU_SMP_lock_Control *lock ) |
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| 82 | { |
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[4402308b] | 83 | #if 0 |
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[e358088] | 84 | _Atomic_Store_and_release( &lock->now_serving, lock->now_serving + 1 ); |
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[4402308b] | 85 | #endif |
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[e358088] | 86 | } |
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| 87 | |
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| 88 | /** |
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| 89 | * @brief Disables interrupts and acquires the CPU SMP lock. |
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| 90 | * |
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[961669d] | 91 | * @param[in,out] lock The CPU SMP lock control. |
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[e358088] | 92 | * @param[out] isr_cookie The ISR cookie. |
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| 93 | */ |
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| 94 | #define _CPU_SMP_lock_ISR_disable_and_acquire( lock, isr_cookie ) \ |
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| 95 | do { \ |
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| 96 | _CPU_ISR_Disable( isr_cookie ); \ |
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| 97 | _CPU_SMP_lock_Acquire( lock ); \ |
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| 98 | } while (0) |
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| 99 | |
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| 100 | /** |
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| 101 | * @brief Releases the CPU SMP lock and enables interrupts. |
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| 102 | * |
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[961669d] | 103 | * @param[in,out] lock The CPU SMP lock control. |
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[e358088] | 104 | * @param[in] isr_cookie The ISR cookie. |
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| 105 | */ |
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| 106 | #define _CPU_SMP_lock_Release_and_ISR_enable( lock, isr_cookie ) \ |
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| 107 | do { \ |
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| 108 | _CPU_SMP_lock_Release( lock ); \ |
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| 109 | _CPU_ISR_Enable( isr_cookie ); \ |
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| 110 | } while (0) |
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| 111 | |
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| 112 | /**@}*/ |
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| 113 | |
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| 114 | #ifdef __cplusplus |
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| 115 | } |
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| 116 | #endif /* __cplusplus */ |
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| 117 | |
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| 118 | #endif /* _RTEMS_SCORE_NO_CPU_SMPLOCK_H */ |
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