1 | /* |
---|
2 | * CORE Semaphore Handler |
---|
3 | * |
---|
4 | * DESCRIPTION: |
---|
5 | * |
---|
6 | * This package is the implementation of the CORE Semaphore Handler. |
---|
7 | * This core object utilizes standard Dijkstra counting semaphores to provide |
---|
8 | * synchronization and mutual exclusion capabilities. |
---|
9 | * |
---|
10 | * COPYRIGHT (c) 1989-1998. |
---|
11 | * On-Line Applications Research Corporation (OAR). |
---|
12 | * Copyright assigned to U.S. Government, 1994. |
---|
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.OARcorp.com/rtems/license.html. |
---|
17 | * |
---|
18 | * $Id$ |
---|
19 | */ |
---|
20 | |
---|
21 | #include <rtems/system.h> |
---|
22 | #include <rtems/score/isr.h> |
---|
23 | #include <rtems/score/coresem.h> |
---|
24 | #include <rtems/score/states.h> |
---|
25 | #include <rtems/score/thread.h> |
---|
26 | #include <rtems/score/threadq.h> |
---|
27 | #if defined(RTEMS_MULTIPROCESSING) |
---|
28 | #include <rtems/score/mpci.h> |
---|
29 | #endif |
---|
30 | |
---|
31 | /*PAGE |
---|
32 | * |
---|
33 | * CORE_semaphore_Initialize |
---|
34 | * |
---|
35 | * This function initialize a semaphore and sets the initial value based |
---|
36 | * on the given count. |
---|
37 | * |
---|
38 | * Input parameters: |
---|
39 | * the_semaphore - the semaphore control block to initialize |
---|
40 | * the_class - the API class of the object |
---|
41 | * the_semaphore_attributes - the attributes specified at create time |
---|
42 | * initial_value - semaphore's initial value |
---|
43 | * proxy_extract_callout - MP specific extract callout |
---|
44 | * |
---|
45 | * Output parameters: NONE |
---|
46 | */ |
---|
47 | |
---|
48 | void _CORE_semaphore_Initialize( |
---|
49 | CORE_semaphore_Control *the_semaphore, |
---|
50 | Objects_Classes the_class, |
---|
51 | CORE_semaphore_Attributes *the_semaphore_attributes, |
---|
52 | unsigned32 initial_value, |
---|
53 | Thread_queue_Extract_callout proxy_extract_callout |
---|
54 | ) |
---|
55 | { |
---|
56 | |
---|
57 | the_semaphore->Attributes = *the_semaphore_attributes; |
---|
58 | the_semaphore->count = initial_value; |
---|
59 | |
---|
60 | _Thread_queue_Initialize( |
---|
61 | &the_semaphore->Wait_queue, |
---|
62 | the_class, |
---|
63 | _CORE_semaphore_Is_priority( the_semaphore_attributes ) ? |
---|
64 | THREAD_QUEUE_DISCIPLINE_PRIORITY : THREAD_QUEUE_DISCIPLINE_FIFO, |
---|
65 | STATES_WAITING_FOR_SEMAPHORE, |
---|
66 | proxy_extract_callout, |
---|
67 | CORE_SEMAPHORE_TIMEOUT |
---|
68 | ); |
---|
69 | } |
---|
70 | |
---|
71 | /*PAGE |
---|
72 | * |
---|
73 | * _CORE_semaphore_Surrender |
---|
74 | * |
---|
75 | * Input parameters: |
---|
76 | * the_semaphore - the semaphore to be flushed |
---|
77 | * id - id of parent semaphore |
---|
78 | * api_semaphore_mp_support - api dependent MP support actions |
---|
79 | * |
---|
80 | * Output parameters: |
---|
81 | * CORE_SEMAPHORE_STATUS_SUCCESSFUL - if successful |
---|
82 | * core error code - if unsuccessful |
---|
83 | * |
---|
84 | * Output parameters: |
---|
85 | */ |
---|
86 | |
---|
87 | CORE_semaphore_Status _CORE_semaphore_Surrender( |
---|
88 | CORE_semaphore_Control *the_semaphore, |
---|
89 | Objects_Id id, |
---|
90 | CORE_semaphore_API_mp_support_callout api_semaphore_mp_support |
---|
91 | ) |
---|
92 | { |
---|
93 | Thread_Control *the_thread; |
---|
94 | |
---|
95 | if ( (the_thread = _Thread_queue_Dequeue(&the_semaphore->Wait_queue)) ) { |
---|
96 | |
---|
97 | if ( !_Objects_Is_local_id( the_thread->Object.id ) ) |
---|
98 | (*api_semaphore_mp_support) ( the_thread, id ); |
---|
99 | |
---|
100 | } else |
---|
101 | the_semaphore->count += 1; |
---|
102 | |
---|
103 | return( CORE_SEMAPHORE_STATUS_SUCCESSFUL ); |
---|
104 | } |
---|
105 | |
---|
106 | /*PAGE |
---|
107 | * |
---|
108 | * _CORE_semaphore_Seize |
---|
109 | * |
---|
110 | * This routine attempts to allocate a core semaphore to the calling thread. |
---|
111 | * |
---|
112 | * Input parameters: |
---|
113 | * the_semaphore - pointer to semaphore control block |
---|
114 | * id - id of object to wait on |
---|
115 | * wait - TRUE if wait is allowed, FALSE otherwise |
---|
116 | * timeout - number of ticks to wait (0 means forever) |
---|
117 | * |
---|
118 | * Output parameters: NONE |
---|
119 | * |
---|
120 | * INTERRUPT LATENCY: |
---|
121 | * available |
---|
122 | * wait |
---|
123 | */ |
---|
124 | |
---|
125 | void _CORE_semaphore_Seize( |
---|
126 | CORE_semaphore_Control *the_semaphore, |
---|
127 | Objects_Id id, |
---|
128 | boolean wait, |
---|
129 | Watchdog_Interval timeout |
---|
130 | ) |
---|
131 | { |
---|
132 | Thread_Control *executing; |
---|
133 | ISR_Level level; |
---|
134 | |
---|
135 | executing = _Thread_Executing; |
---|
136 | executing->Wait.return_code = CORE_SEMAPHORE_STATUS_SUCCESSFUL; |
---|
137 | _ISR_Disable( level ); |
---|
138 | if ( the_semaphore->count != 0 ) { |
---|
139 | the_semaphore->count -= 1; |
---|
140 | _ISR_Enable( level ); |
---|
141 | return; |
---|
142 | } |
---|
143 | |
---|
144 | if ( !wait ) { |
---|
145 | _ISR_Enable( level ); |
---|
146 | executing->Wait.return_code = CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT; |
---|
147 | return; |
---|
148 | } |
---|
149 | |
---|
150 | _Thread_queue_Enter_critical_section( &the_semaphore->Wait_queue ); |
---|
151 | executing->Wait.queue = &the_semaphore->Wait_queue; |
---|
152 | executing->Wait.id = id; |
---|
153 | _ISR_Enable( level ); |
---|
154 | |
---|
155 | _Thread_queue_Enqueue( &the_semaphore->Wait_queue, timeout ); |
---|
156 | } |
---|
157 | |
---|
158 | |
---|
159 | /*PAGE |
---|
160 | * |
---|
161 | * _CORE_semaphore_Flush |
---|
162 | * |
---|
163 | * This function a flushes the semaphore's task wait queue. |
---|
164 | * |
---|
165 | * Input parameters: |
---|
166 | * the_semaphore - the semaphore to be flushed |
---|
167 | * remote_extract_callout - function to invoke remotely |
---|
168 | * status - status to pass to thread |
---|
169 | * |
---|
170 | * Output parameters: NONE |
---|
171 | */ |
---|
172 | |
---|
173 | void _CORE_semaphore_Flush( |
---|
174 | CORE_semaphore_Control *the_semaphore, |
---|
175 | Thread_queue_Flush_callout remote_extract_callout, |
---|
176 | unsigned32 status |
---|
177 | ) |
---|
178 | { |
---|
179 | |
---|
180 | _Thread_queue_Flush( |
---|
181 | &the_semaphore->Wait_queue, |
---|
182 | remote_extract_callout, |
---|
183 | status |
---|
184 | ); |
---|
185 | |
---|
186 | } |
---|