1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief POSIX Priority Support |
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5 | * |
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6 | * This include file defines the interface to the POSIX priority |
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7 | * implementation. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * COPYRIGHT (c) 1989-2011. |
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12 | * On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.org/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_POSIX_PRIORITYIMPL_H |
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20 | #define _RTEMS_POSIX_PRIORITYIMPL_H |
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21 | |
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22 | #include <rtems/score/scheduler.h> |
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23 | #include <rtems/score/assert.h> |
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24 | |
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25 | #ifdef __cplusplus |
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26 | extern "C" { |
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27 | #endif |
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28 | |
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29 | /** |
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30 | * @defgroup POSIX_PRIORITY POSIX Priority Support |
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31 | * |
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32 | * @ingroup POSIXAPI |
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33 | * |
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34 | * @brief Interface to the POSIX Priority Implementation. |
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35 | * |
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36 | * @{ |
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37 | */ |
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38 | |
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39 | /** |
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40 | * This is the numerically least important POSIX priority. |
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41 | */ |
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42 | #define POSIX_SCHEDULER_MINIMUM_PRIORITY (1) |
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43 | |
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44 | /** |
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45 | * @brief Gets the maximum POSIX API priority for this scheduler instance. |
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46 | * |
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47 | * Such a priority is valid. A scheduler instance may support priority values |
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48 | * that are not representable as an integer. |
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49 | * |
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50 | * @return The maximum POSIX API priority for this scheduler instance. |
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51 | */ |
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52 | RTEMS_INLINE_ROUTINE int _POSIX_Priority_Get_maximum( |
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53 | const Scheduler_Control *scheduler |
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54 | ) |
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55 | { |
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56 | _Assert( (int) scheduler->maximum_priority > 1 ); |
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57 | return (int) scheduler->maximum_priority - 1; |
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58 | } |
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59 | |
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60 | /** |
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61 | * @brief Converts the POSIX API priority to the corresponding SuperCore |
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62 | * priority and validates it. |
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63 | * |
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64 | * According to POSIX, numerically higher values represent higher priorities. |
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65 | * Thus, SuperCore has priorities run in the opposite sense of the POSIX API. |
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66 | * |
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67 | * Let N be the maximum priority of this scheduler instance. The SuperCore |
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68 | * priority zero is system reserved (PRIORITY_PSEUDO_ISR). There are only |
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69 | * N - 1 POSIX API priority levels since a thread at SuperCore priority N would |
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70 | * never run because of the idle threads. This is necessary because GNAT maps |
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71 | * the lowest Ada task priority to the lowest thread priority. The lowest |
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72 | * priority Ada task should get to run, so there is a fundamental conflict with |
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73 | * having N priorities. |
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74 | * |
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75 | * @param[in] scheduler The scheduler instance. |
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76 | * @param[in] priority The POSIX API priority to convert and validate. |
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77 | * @param[out] valid Indicates if the POSIX API priority is valid and a |
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78 | * corresponding SuperCore priority in the specified scheduler instance |
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79 | * exists. |
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80 | * |
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81 | * @return The corresponding SuperCore priority. |
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82 | */ |
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83 | Priority_Control _POSIX_Priority_To_core( |
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84 | const Scheduler_Control *scheduler, |
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85 | int priority, |
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86 | bool *valid |
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87 | ); |
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88 | |
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89 | /** |
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90 | * @brief Converts the SuperCore priority to the corresponding POSIX API |
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91 | * priority. |
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92 | * |
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93 | * @param[in] scheduler The scheduler instance. |
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94 | * @param[in] priority The SuperCore priority to convert. |
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95 | * |
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96 | * @return The corresponding POSIX API priority. |
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97 | */ |
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98 | int _POSIX_Priority_From_core( |
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99 | const Scheduler_Control *scheduler, |
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100 | Priority_Control priority |
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101 | ); |
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102 | |
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103 | /** @} */ |
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104 | |
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105 | #ifdef __cplusplus |
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106 | } |
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107 | #endif |
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108 | |
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109 | #endif |
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