1 | /** |
---|
2 | * @file rtems/score/coresem.h |
---|
3 | * |
---|
4 | * This include file contains all the constants and structures associated |
---|
5 | * with the Counting Semaphore Handler. A counting semaphore is the |
---|
6 | * standard Dijkstra binary semaphore used to provide synchronization |
---|
7 | * and mutual exclusion capabilities. |
---|
8 | */ |
---|
9 | |
---|
10 | /* |
---|
11 | * COPYRIGHT (c) 1989-2008. |
---|
12 | * On-Line Applications Research Corporation (OAR). |
---|
13 | * |
---|
14 | * The license and distribution terms for this file may be |
---|
15 | * found in the file LICENSE in this distribution or at |
---|
16 | * http://www.rtems.com/license/LICENSE. |
---|
17 | */ |
---|
18 | |
---|
19 | #ifndef _RTEMS_SCORE_CORESEM_H |
---|
20 | #define _RTEMS_SCORE_CORESEM_H |
---|
21 | |
---|
22 | /** |
---|
23 | * @defgroup ScoreSemaphore Semaphore Handler |
---|
24 | * |
---|
25 | * @ingroup Score |
---|
26 | * |
---|
27 | * This handler encapsulates functionality which provides the foundation |
---|
28 | * Semaphore services used in all of the APIs supported by RTEMS. |
---|
29 | */ |
---|
30 | /**@{*/ |
---|
31 | |
---|
32 | #include <rtems/score/thread.h> |
---|
33 | #include <rtems/score/threadq.h> |
---|
34 | #include <rtems/score/priority.h> |
---|
35 | #include <rtems/score/watchdog.h> |
---|
36 | |
---|
37 | #ifdef __cplusplus |
---|
38 | extern "C" { |
---|
39 | #endif |
---|
40 | |
---|
41 | #if defined(RTEMS_POSIX_API) || defined(RTEMS_MULTIPROCESSING) |
---|
42 | #define RTEMS_SCORE_CORESEM_ENABLE_SEIZE_BODY |
---|
43 | #endif |
---|
44 | |
---|
45 | /** |
---|
46 | * The following type defines the callout which the API provides |
---|
47 | * to support global/multiprocessor operations on semaphores. |
---|
48 | */ |
---|
49 | typedef void ( *CORE_semaphore_API_mp_support_callout )( |
---|
50 | Thread_Control *, |
---|
51 | Objects_Id |
---|
52 | ); |
---|
53 | |
---|
54 | /** |
---|
55 | * Blocking disciplines for a semaphore. |
---|
56 | */ |
---|
57 | typedef enum { |
---|
58 | /** This specifies that threads will wait for the semaphore in FIFO order. */ |
---|
59 | CORE_SEMAPHORE_DISCIPLINES_FIFO, |
---|
60 | /** This specifies that threads will wait for the semaphore in |
---|
61 | * priority order. |
---|
62 | */ |
---|
63 | CORE_SEMAPHORE_DISCIPLINES_PRIORITY |
---|
64 | } CORE_semaphore_Disciplines; |
---|
65 | |
---|
66 | /** |
---|
67 | * Core Semaphore handler return statuses. |
---|
68 | */ |
---|
69 | typedef enum { |
---|
70 | /** This status indicates that the operation completed successfully. */ |
---|
71 | CORE_SEMAPHORE_STATUS_SUCCESSFUL, |
---|
72 | /** This status indicates that the calling task did not want to block |
---|
73 | * and the operation was unable to complete immediately because the |
---|
74 | * resource was unavailable. |
---|
75 | */ |
---|
76 | CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT, |
---|
77 | /** This status indicates that the thread was blocked waiting for an |
---|
78 | * operation to complete and the semaphore was deleted. |
---|
79 | */ |
---|
80 | CORE_SEMAPHORE_WAS_DELETED, |
---|
81 | /** This status indicates that the calling task was willing to block |
---|
82 | * but the operation was unable to complete within the time allotted |
---|
83 | * because the resource never became available. |
---|
84 | */ |
---|
85 | CORE_SEMAPHORE_TIMEOUT, |
---|
86 | /** This status indicates that an attempt was made to unlock the semaphore |
---|
87 | * and this would have made its count greater than that allowed. |
---|
88 | */ |
---|
89 | CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED |
---|
90 | } CORE_semaphore_Status; |
---|
91 | |
---|
92 | /** |
---|
93 | * @brief Core Semaphore Last Status |
---|
94 | * |
---|
95 | * This is the last status value. |
---|
96 | */ |
---|
97 | #define CORE_SEMAPHORE_STATUS_LAST CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED |
---|
98 | |
---|
99 | /** |
---|
100 | * The following defines the control block used to manage the |
---|
101 | * attributes of each semaphore. |
---|
102 | */ |
---|
103 | typedef struct { |
---|
104 | /** This element indicates the maximum count this semaphore may have. */ |
---|
105 | uint32_t maximum_count; |
---|
106 | /** This field indicates whether threads waiting on the semaphore block in |
---|
107 | * FIFO or priority order. |
---|
108 | */ |
---|
109 | CORE_semaphore_Disciplines discipline; |
---|
110 | } CORE_semaphore_Attributes; |
---|
111 | |
---|
112 | /** |
---|
113 | * The following defines the control block used to manage each |
---|
114 | * counting semaphore. |
---|
115 | */ |
---|
116 | typedef struct { |
---|
117 | /** This field is the Waiting Queue used to manage the set of tasks |
---|
118 | * which are blocked waiting to obtain the semaphore. |
---|
119 | */ |
---|
120 | Thread_queue_Control Wait_queue; |
---|
121 | /** This element is the set of attributes which define this instance's |
---|
122 | * behavior. |
---|
123 | */ |
---|
124 | CORE_semaphore_Attributes Attributes; |
---|
125 | /** This element contains the current count of this semaphore. */ |
---|
126 | uint32_t count; |
---|
127 | } CORE_semaphore_Control; |
---|
128 | |
---|
129 | /** |
---|
130 | * @brief Core Semaphore Initialize |
---|
131 | * |
---|
132 | * DESCRIPTION: |
---|
133 | * |
---|
134 | * This package is the implementation of the CORE Semaphore Handler. |
---|
135 | * This core object utilizes standard Dijkstra counting semaphores to provide |
---|
136 | * synchronization and mutual exclusion capabilities. |
---|
137 | * |
---|
138 | * This routine initializes the semaphore based on the parameters passed. |
---|
139 | * |
---|
140 | * @param[in] the_semaphore is the semaphore to initialize |
---|
141 | * @param[in] the_semaphore_attributes define the behavior of this instance |
---|
142 | * @param[in] initial_value is the initial count of the semaphore |
---|
143 | */ |
---|
144 | void _CORE_semaphore_Initialize( |
---|
145 | CORE_semaphore_Control *the_semaphore, |
---|
146 | CORE_semaphore_Attributes *the_semaphore_attributes, |
---|
147 | uint32_t initial_value |
---|
148 | ); |
---|
149 | |
---|
150 | #if defined(RTEMS_SCORE_CORESEM_ENABLE_SEIZE_BODY) |
---|
151 | /** |
---|
152 | * This routine attempts to receive a unit from @a the_semaphore. |
---|
153 | * If a unit is available or if the wait flag is false, then the routine |
---|
154 | * returns. Otherwise, the calling task is blocked until a unit becomes |
---|
155 | * available. |
---|
156 | * |
---|
157 | * @param[in] the_semaphore is the semaphore to seize |
---|
158 | * @param[in] id is the Id of the API level Semaphore object associated |
---|
159 | * with this instance of a SuperCore Semaphore |
---|
160 | * @param[in] wait indicates if the caller is willing to block |
---|
161 | * @param[in] timeout is the number of ticks the calling thread is willing |
---|
162 | * to wait if @a wait is true. |
---|
163 | */ |
---|
164 | void _CORE_semaphore_Seize( |
---|
165 | CORE_semaphore_Control *the_semaphore, |
---|
166 | Objects_Id id, |
---|
167 | bool wait, |
---|
168 | Watchdog_Interval timeout |
---|
169 | ); |
---|
170 | #endif |
---|
171 | |
---|
172 | /** |
---|
173 | * This routine frees a unit to the semaphore. If a task was blocked waiting |
---|
174 | * for a unit from this semaphore, then that task will be readied and the unit |
---|
175 | * given to that task. Otherwise, the unit will be returned to the semaphore. |
---|
176 | * |
---|
177 | * @param[in] the_semaphore is the semaphore to surrender |
---|
178 | * @param[in] id is the Id of the API level Semaphore object associated |
---|
179 | * with this instance of a SuperCore Semaphore |
---|
180 | * @param[in] api_semaphore_mp_support is the routine to invoke if the |
---|
181 | * thread unblocked is remote |
---|
182 | * |
---|
183 | * @return an indication of whether the routine succeeded or failed |
---|
184 | */ |
---|
185 | CORE_semaphore_Status _CORE_semaphore_Surrender( |
---|
186 | CORE_semaphore_Control *the_semaphore, |
---|
187 | Objects_Id id, |
---|
188 | CORE_semaphore_API_mp_support_callout api_semaphore_mp_support |
---|
189 | ); |
---|
190 | |
---|
191 | /** |
---|
192 | * @brief Core Semaphore Flush |
---|
193 | * |
---|
194 | * DESCRIPTION: |
---|
195 | * This package is the implementation of the CORE Semaphore Handler. |
---|
196 | * This core object utilizes standard Dijkstra counting semaphores to provide |
---|
197 | * synchronization and mutual exclusion capabilities. |
---|
198 | * |
---|
199 | * This routine assists in the deletion of a semaphore by flushing the |
---|
200 | * associated wait queue. |
---|
201 | * |
---|
202 | * @param[in] the_semaphore is the semaphore to flush |
---|
203 | * @param[in] remote_extract_callout is the routine to invoke if the |
---|
204 | * thread unblocked is remote |
---|
205 | * @param[in] status is the status to be returned to the unblocked thread |
---|
206 | */ |
---|
207 | void _CORE_semaphore_Flush( |
---|
208 | CORE_semaphore_Control *the_semaphore, |
---|
209 | Thread_queue_Flush_callout remote_extract_callout, |
---|
210 | uint32_t status |
---|
211 | ); |
---|
212 | |
---|
213 | #ifndef __RTEMS_APPLICATION__ |
---|
214 | #include <rtems/score/coresem.inl> |
---|
215 | #endif |
---|
216 | |
---|
217 | #ifdef __cplusplus |
---|
218 | } |
---|
219 | #endif |
---|
220 | |
---|
221 | /**@}*/ |
---|
222 | |
---|
223 | #endif |
---|
224 | /* end of include file */ |
---|