source: rtems/c/src/exec/rtems/src/event.c @ a8cd94a

4.104.114.84.95
Last change on this file since a8cd94a was a8cd94a, checked in by Joel Sherrill <joel.sherrill@…>, on Dec 1, 1995 at 7:28:58 PM

Replaced critical section algorithm to correct race conditions.

  • Property mode set to 100644
File size: 8.0 KB
Line 
1/*
2 *  Event Manager
3 *
4 *  COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
5 *  On-Line Applications Research Corporation (OAR).
6 *  All rights assigned to U.S. Government, 1994.
7 *
8 *  This material may be reproduced by or for the U.S. Government pursuant
9 *  to the copyright license under the clause at DFARS 252.227-7013.  This
10 *  notice must appear in all copies of this file and its derivatives.
11 *
12 *  $Id$
13 */
14
15#include <rtems/system.h>
16#include <rtems/rtems/status.h>
17#include <rtems/rtems/event.h>
18#include <rtems/score/isr.h>
19#include <rtems/score/object.h>
20#include <rtems/rtems/options.h>
21#include <rtems/score/states.h>
22#include <rtems/score/thread.h>
23#include <rtems/rtems/tasks.h>
24
25/*PAGE
26 *
27 *  rtems_event_send
28 *
29 *  This directive allows a thread send an event set to another thread.
30 *
31 *  Input parameters:
32 *    id    - thread id
33 *    event - event set
34 *
35 *  Output parameters:
36 *    RTEMS_SUCCESSFUL - if successful
37 *    error code - if unsuccessful
38 */
39
40rtems_status_code rtems_event_send(
41  Objects_Id         id,
42  rtems_event_set event_in
43)
44{
45  register Thread_Control *the_thread;
46  Objects_Locations        location;
47  RTEMS_API_Control       *api;
48
49  the_thread = _Thread_Get( id, &location );
50  switch ( location ) {
51    case OBJECTS_ERROR:
52      return RTEMS_INVALID_ID;
53    case OBJECTS_REMOTE:
54      return(
55        _Event_MP_Send_request_packet(
56          EVENT_MP_SEND_REQUEST,
57          id,
58          event_in
59        )
60      );
61    case OBJECTS_LOCAL:
62      api = the_thread->API_Extensions[ THREAD_API_RTEMS ];
63      _Event_sets_Post( event_in, &api->pending_events );
64      _Event_Surrender( the_thread );
65      _Thread_Enable_dispatch();
66      return RTEMS_SUCCESSFUL;
67  }
68
69  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */
70}
71
72/*PAGE
73 *
74 *  rtems_event_receive
75 *
76 *  This directive allows a thread to receive a set of events.
77 *
78 *  Input parameters:
79 *    event_in   - input event condition
80 *    option_set - options
81 *    ticks      - number of ticks to wait (0 means wait forever)
82 *    event_out  - pointer to output event set
83 *
84 *  Output parameters:
85 *    event out         - event set
86 *    RTEMS_SUCCESSFUL - if successful
87 *    error code        - if unsuccessful
88 */
89
90rtems_status_code rtems_event_receive(
91  rtems_event_set  event_in,
92  rtems_option     option_set,
93  rtems_interval   ticks,
94  rtems_event_set *event_out
95)
96{
97  RTEMS_API_Control       *api;
98
99  api = _Thread_Executing->API_Extensions[ THREAD_API_RTEMS ];
100
101  if ( _Event_sets_Is_empty( event_in ) ) {
102    *event_out = api->pending_events;
103    return RTEMS_SUCCESSFUL;
104  }
105
106  _Thread_Disable_dispatch();
107  _Event_Seize( event_in, option_set, ticks, event_out );
108  _Thread_Enable_dispatch();
109  return( _Thread_Executing->Wait.return_code );
110}
111
112
113/*PAGE
114 *
115 *  _Event_Seize
116 *
117 *  This routine attempts to satisfy the requested event condition
118 *  for the running thread.
119 *
120 *  Input parameters:
121 *    event_in   - the event condition to satisfy
122 *    option_set - acquire event options
123 *    ticks      - interval to wait
124 *    event_out  - pointer to event set output area
125 *
126 *  Output parameters: NONE
127 *    *event_out - event set output area filled in
128 *
129 *  INTERRUPT LATENCY:
130 *    available
131 *    wait
132 *    check sync
133 */
134
135void _Event_Seize(
136  rtems_event_set  event_in,
137  rtems_option     option_set,
138  rtems_interval   ticks,
139  rtems_event_set *event_out
140)
141{
142  Thread_Control    *executing;
143  rtems_event_set    seized_events;
144  rtems_event_set    pending_events;
145  ISR_Level          level;
146  RTEMS_API_Control  *api;
147
148  executing = _Thread_Executing;
149  executing->Wait.return_code = RTEMS_SUCCESSFUL;
150
151  api = executing->API_Extensions[ THREAD_API_RTEMS ];
152
153  _ISR_Disable( level );
154  pending_events = api->pending_events;
155  seized_events  = _Event_sets_Get( pending_events, event_in );
156
157  if ( !_Event_sets_Is_empty( seized_events ) &&
158       (seized_events == event_in || _Options_Is_any( option_set )) ) {
159    api->pending_events =
160      _Event_sets_Clear( pending_events, seized_events );
161    _ISR_Enable( level );
162    *event_out = seized_events;
163    return;
164  }
165
166  if ( _Options_Is_no_wait( option_set ) ) {
167    _ISR_Enable( level );
168    executing->Wait.return_code = RTEMS_UNSATISFIED;
169    *event_out = seized_events;
170    return;
171  }
172
173  _Event_Sync       = TRUE;
174  _Event_Sync_state = EVENT_SYNC_NOTHING_HAPPENED;
175
176  executing->Wait.option            = (unsigned32) option_set;
177  executing->Wait.count             = (unsigned32) event_in;
178  executing->Wait.return_argument   = event_out;
179
180  _ISR_Enable( level );
181
182  if ( ticks ) {
183    _Watchdog_Initialize(
184      &executing->Timer,
185      _Event_Timeout,
186      executing->Object.id,
187      NULL
188    );
189    _Watchdog_Insert_ticks(
190      &executing->Timer,
191      ticks,
192      WATCHDOG_ACTIVATE_NOW
193    );
194  }
195
196  _Thread_Set_state( executing, STATES_WAITING_FOR_EVENT );
197
198  _ISR_Disable( level );
199  if ( _Event_Sync == TRUE ) {
200    _Event_Sync = FALSE;
201    _ISR_Enable( level );
202    return;
203  }
204  if ( _Event_Sync_state == EVENT_SYNC_TIMEOUT )
205    executing->Wait.return_code = RTEMS_TIMEOUT;
206  _ISR_Enable( level );
207  if ( ticks )
208    (void) _Watchdog_Remove( &executing->Timer );
209  _Thread_Unblock( executing );
210  return;
211}
212
213/*PAGE
214 *
215 *  _Event_Surrender
216 *
217 *  This routines remove a thread from the specified threadq.
218 *
219 *  Input parameters:
220 *    the_thread - pointer to thread to be dequeued
221 *
222 *  Output parameters: NONE
223 *
224 *  INTERRUPT LATENCY:
225 *    before flash
226 *    after flash
227 *    check sync
228 */
229
230void _Event_Surrender(
231  Thread_Control *the_thread
232)
233{
234  ISR_Level           level;
235  rtems_event_set     pending_events;
236  rtems_event_set     event_condition;
237  rtems_event_set     seized_events;
238  rtems_option        option_set;
239  RTEMS_API_Control  *api;
240
241  api = the_thread->API_Extensions[ THREAD_API_RTEMS ];
242
243  option_set = (rtems_option) the_thread->Wait.option;
244
245  _ISR_Disable( level );
246  pending_events  = api->pending_events;
247  event_condition = (rtems_event_set) the_thread->Wait.count;
248
249  seized_events = _Event_sets_Get( pending_events, event_condition );
250
251  if ( !_Event_sets_Is_empty( seized_events ) ) {
252    if ( _States_Is_waiting_for_event( the_thread->current_state ) ) {
253      if ( seized_events == event_condition || _Options_Is_any( option_set ) ) {
254        api->pending_events =
255           _Event_sets_Clear( pending_events, seized_events );
256        *(rtems_event_set *)the_thread->Wait.return_argument = seized_events;
257
258        _ISR_Flash( level );
259
260        if ( !_Watchdog_Is_active( &the_thread->Timer ) ) {
261          _ISR_Enable( level );
262          _Thread_Unblock( the_thread );
263        }
264        else {
265          _Watchdog_Deactivate( &the_thread->Timer );
266          _ISR_Enable( level );
267          (void) _Watchdog_Remove( &the_thread->Timer );
268          _Thread_Unblock( the_thread );
269        }
270        return;
271      }
272    }
273    else if ( _Event_Sync == TRUE && _Thread_Is_executing( the_thread ) ) {
274      if ( seized_events == event_condition || _Options_Is_any( option_set ) ) {
275        api->pending_events = _Event_sets_Clear( pending_events,seized_events );
276        *(rtems_event_set *)the_thread->Wait.return_argument = seized_events;
277        _Event_Sync_state = EVENT_SYNC_SATISFIED;
278      }
279    }
280  }
281  _ISR_Enable( level );
282}
283
284/*PAGE
285 *
286 *  _Event_Timeout
287 *
288 *  This routine processes a thread which timeouts while waiting to
289 *  receive an event_set. It is called by the watchdog handler.
290 *
291 *  Input parameters:
292 *    id - thread id
293 *
294 *  Output parameters: NONE
295 */
296
297void _Event_Timeout(
298  Objects_Id  id,
299  void       *ignored
300)
301{
302  Thread_Control *the_thread;
303  Objects_Locations      location;
304
305  the_thread = _Thread_Get( id, &location );
306  switch ( location ) {
307    case OBJECTS_ERROR:
308    case OBJECTS_REMOTE:  /* impossible */
309      break;
310    case OBJECTS_LOCAL:
311      if ( _Event_Sync == TRUE && _Thread_Is_executing( the_thread ) ) {
312        if ( _Event_Sync_state != EVENT_SYNC_SATISFIED )
313          _Event_Sync_state = EVENT_SYNC_TIMEOUT;
314      } else {
315        the_thread->Wait.return_code = RTEMS_TIMEOUT;
316        _Thread_Unblock( the_thread );
317      }
318      _Thread_Unnest_dispatch();
319      break;
320  }
321}
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