source: rtems/cpukit/score/src/coresem.c @ 97e2729d

4.104.114.84.9
Last change on this file since 97e2729d was 97e2729d, checked in by Joel Sherrill <joel.sherrill@…>, on Nov 23, 1998 at 5:38:09 PM

Added --disable-multiprocessing flag and modified a lot of files to make
it work.

  • Property mode set to 100644
File size: 4.8 KB
Line 
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
48void _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
87CORE_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
125void _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 
173void _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}
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