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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Source/] [croutine.c] - Blame information for rev 851

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1 572 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
3
 
4
    ***************************************************************************
5
    *                                                                         *
6
    * If you are:                                                             *
7
    *                                                                         *
8
    *    + New to FreeRTOS,                                                   *
9
    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
10
    *    + Looking for basic training,                                        *
11
    *    + Wanting to improve your FreeRTOS skills and productivity           *
12
    *                                                                         *
13
    * then take a look at the FreeRTOS books - available as PDF or paperback  *
14
    *                                                                         *
15
    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
16
    *                  http://www.FreeRTOS.org/Documentation                  *
17
    *                                                                         *
18
    * A pdf reference manual is also available.  Both are usually delivered   *
19
    * to your inbox within 20 minutes to two hours when purchased between 8am *
20
    * and 8pm GMT (although please allow up to 24 hours in case of            *
21
    * exceptional circumstances).  Thank you for your support!                *
22
    *                                                                         *
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    ***************************************************************************
24
 
25
    This file is part of the FreeRTOS distribution.
26
 
27
    FreeRTOS is free software; you can redistribute it and/or modify it under
28
    the terms of the GNU General Public License (version 2) as published by the
29
    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
30
    ***NOTE*** The exception to the GPL is included to allow you to distribute
31
    a combined work that includes FreeRTOS without being obliged to provide the
32
    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
34
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
35
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
36
    more details. You should have received a copy of the GNU General Public
37
    License and the FreeRTOS license exception along with FreeRTOS; if not it
38
    can be viewed here: http://www.freertos.org/a00114.html and also obtained
39
    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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47
    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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50
    http://www.OpenRTOS.com - Commercial support, development, porting,
51
    licensing and training services.
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*/
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54
#include "FreeRTOS.h"
55
#include "task.h"
56
#include "croutine.h"
57
 
58
/*
59
 * Some kernel aware debuggers require data to be viewed to be global, rather
60
 * than file scope.
61
 */
62
#ifdef portREMOVE_STATIC_QUALIFIER
63
        #define static
64
#endif
65
 
66
 
67
/* Lists for ready and blocked co-routines. --------------------*/
68
static xList pxReadyCoRoutineLists[ configMAX_CO_ROUTINE_PRIORITIES ];  /*< Prioritised ready co-routines. */
69
static xList xDelayedCoRoutineList1;                                                                    /*< Delayed co-routines. */
70
static xList xDelayedCoRoutineList2;                                                                    /*< Delayed co-routines (two lists are used - one for delays that have overflowed the current tick count. */
71
static xList * pxDelayedCoRoutineList;                                                                  /*< Points to the delayed co-routine list currently being used. */
72
static xList * pxOverflowDelayedCoRoutineList;                                                  /*< Points to the delayed co-routine list currently being used to hold co-routines that have overflowed the current tick count. */
73
static xList xPendingReadyCoRoutineList;                                                                                        /*< Holds co-routines that have been readied by an external event.  They cannot be added directly to the ready lists as the ready lists cannot be accessed by interrupts. */
74
 
75
/* Other file private variables. --------------------------------*/
76
corCRCB * pxCurrentCoRoutine = NULL;
77
static unsigned portBASE_TYPE uxTopCoRoutineReadyPriority = 0;
78
static portTickType xCoRoutineTickCount = 0, xLastTickCount = 0, xPassedTicks = 0;
79
 
80
/* The initial state of the co-routine when it is created. */
81
#define corINITIAL_STATE        ( 0 )
82
 
83
/*
84
 * Place the co-routine represented by pxCRCB into the appropriate ready queue
85
 * for the priority.  It is inserted at the end of the list.
86
 *
87
 * This macro accesses the co-routine ready lists and therefore must not be
88
 * used from within an ISR.
89
 */
90
#define prvAddCoRoutineToReadyQueue( pxCRCB )                                                                                                                                           \
91
{                                                                                                                                                                                                                                       \
92
        if( pxCRCB->uxPriority > uxTopCoRoutineReadyPriority )                                                                                                                  \
93
        {                                                                                                                                                                                                                               \
94
                uxTopCoRoutineReadyPriority = pxCRCB->uxPriority;                                                                                                                       \
95
        }                                                                                                                                                                                                                               \
96
        vListInsertEnd( ( xList * ) &( pxReadyCoRoutineLists[ pxCRCB->uxPriority ] ), &( pxCRCB->xGenericListItem ) );  \
97
}
98
 
99
/*
100
 * Utility to ready all the lists used by the scheduler.  This is called
101
 * automatically upon the creation of the first co-routine.
102
 */
103
static void prvInitialiseCoRoutineLists( void );
104
 
105
/*
106
 * Co-routines that are readied by an interrupt cannot be placed directly into
107
 * the ready lists (there is no mutual exclusion).  Instead they are placed in
108
 * in the pending ready list in order that they can later be moved to the ready
109
 * list by the co-routine scheduler.
110
 */
111
static void prvCheckPendingReadyList( void );
112
 
113
/*
114
 * Macro that looks at the list of co-routines that are currently delayed to
115
 * see if any require waking.
116
 *
117
 * Co-routines are stored in the queue in the order of their wake time -
118
 * meaning once one co-routine has been found whose timer has not expired
119
 * we need not look any further down the list.
120
 */
121
static void prvCheckDelayedList( void );
122
 
123
/*-----------------------------------------------------------*/
124
 
125
signed portBASE_TYPE xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, unsigned portBASE_TYPE uxPriority, unsigned portBASE_TYPE uxIndex )
126
{
127
signed portBASE_TYPE xReturn;
128
corCRCB *pxCoRoutine;
129
 
130
        /* Allocate the memory that will store the co-routine control block. */
131
        pxCoRoutine = ( corCRCB * ) pvPortMalloc( sizeof( corCRCB ) );
132
        if( pxCoRoutine )
133
        {
134
                /* If pxCurrentCoRoutine is NULL then this is the first co-routine to
135
                be created and the co-routine data structures need initialising. */
136
                if( pxCurrentCoRoutine == NULL )
137
                {
138
                        pxCurrentCoRoutine = pxCoRoutine;
139
                        prvInitialiseCoRoutineLists();
140
                }
141
 
142
                /* Check the priority is within limits. */
143
                if( uxPriority >= configMAX_CO_ROUTINE_PRIORITIES )
144
                {
145
                        uxPriority = configMAX_CO_ROUTINE_PRIORITIES - 1;
146
                }
147
 
148
                /* Fill out the co-routine control block from the function parameters. */
149
                pxCoRoutine->uxState = corINITIAL_STATE;
150
                pxCoRoutine->uxPriority = uxPriority;
151
                pxCoRoutine->uxIndex = uxIndex;
152
                pxCoRoutine->pxCoRoutineFunction = pxCoRoutineCode;
153
 
154
                /* Initialise all the other co-routine control block parameters. */
155
                vListInitialiseItem( &( pxCoRoutine->xGenericListItem ) );
156
                vListInitialiseItem( &( pxCoRoutine->xEventListItem ) );
157
 
158
                /* Set the co-routine control block as a link back from the xListItem.
159
                This is so we can get back to the containing CRCB from a generic item
160
                in a list. */
161
                listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xGenericListItem ), pxCoRoutine );
162
                listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xEventListItem ), pxCoRoutine );
163
 
164
                /* Event lists are always in priority order. */
165
                listSET_LIST_ITEM_VALUE( &( pxCoRoutine->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
166
 
167
                /* Now the co-routine has been initialised it can be added to the ready
168
                list at the correct priority. */
169
                prvAddCoRoutineToReadyQueue( pxCoRoutine );
170
 
171
                xReturn = pdPASS;
172
        }
173
        else
174
        {
175
                xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
176
        }
177
 
178
        return xReturn;
179
}
180
/*-----------------------------------------------------------*/
181
 
182
void vCoRoutineAddToDelayedList( portTickType xTicksToDelay, xList *pxEventList )
183
{
184
portTickType xTimeToWake;
185
 
186
        /* Calculate the time to wake - this may overflow but this is
187
        not a problem. */
188
        xTimeToWake = xCoRoutineTickCount + xTicksToDelay;
189
 
190
        /* We must remove ourselves from the ready list before adding
191
        ourselves to the blocked list as the same list item is used for
192
        both lists. */
193
        vListRemove( ( xListItem * ) &( pxCurrentCoRoutine->xGenericListItem ) );
194
 
195
        /* The list item will be inserted in wake time order. */
196
        listSET_LIST_ITEM_VALUE( &( pxCurrentCoRoutine->xGenericListItem ), xTimeToWake );
197
 
198
        if( xTimeToWake < xCoRoutineTickCount )
199
        {
200
                /* Wake time has overflowed.  Place this item in the
201
                overflow list. */
202
                vListInsert( ( xList * ) pxOverflowDelayedCoRoutineList, ( xListItem * ) &( pxCurrentCoRoutine->xGenericListItem ) );
203
        }
204
        else
205
        {
206
                /* The wake time has not overflowed, so we can use the
207
                current block list. */
208
                vListInsert( ( xList * ) pxDelayedCoRoutineList, ( xListItem * ) &( pxCurrentCoRoutine->xGenericListItem ) );
209
        }
210
 
211
        if( pxEventList )
212
        {
213
                /* Also add the co-routine to an event list.  If this is done then the
214
                function must be called with interrupts disabled. */
215
                vListInsert( pxEventList, &( pxCurrentCoRoutine->xEventListItem ) );
216
        }
217
}
218
/*-----------------------------------------------------------*/
219
 
220
static void prvCheckPendingReadyList( void )
221
{
222
        /* Are there any co-routines waiting to get moved to the ready list?  These
223
        are co-routines that have been readied by an ISR.  The ISR cannot access
224
        the     ready lists itself. */
225
        while( !listLIST_IS_EMPTY( &xPendingReadyCoRoutineList ) )
226
        {
227
                corCRCB *pxUnblockedCRCB;
228
 
229
                /* The pending ready list can be accessed by an ISR. */
230
                portDISABLE_INTERRUPTS();
231
                {
232
                        pxUnblockedCRCB = ( corCRCB * ) listGET_OWNER_OF_HEAD_ENTRY( (&xPendingReadyCoRoutineList) );
233
                        vListRemove( &( pxUnblockedCRCB->xEventListItem ) );
234
                }
235
                portENABLE_INTERRUPTS();
236
 
237
                vListRemove( &( pxUnblockedCRCB->xGenericListItem ) );
238
                prvAddCoRoutineToReadyQueue( pxUnblockedCRCB );
239
        }
240
}
241
/*-----------------------------------------------------------*/
242
 
243
static void prvCheckDelayedList( void )
244
{
245
corCRCB *pxCRCB;
246
 
247
        xPassedTicks = xTaskGetTickCount() - xLastTickCount;
248
        while( xPassedTicks )
249
        {
250
                xCoRoutineTickCount++;
251
                xPassedTicks--;
252
 
253
                /* If the tick count has overflowed we need to swap the ready lists. */
254
                if( xCoRoutineTickCount == 0 )
255
                {
256
                        xList * pxTemp;
257
 
258
                        /* Tick count has overflowed so we need to swap the delay lists.  If there are
259
                        any items in pxDelayedCoRoutineList here then there is an error! */
260
                        pxTemp = pxDelayedCoRoutineList;
261
                        pxDelayedCoRoutineList = pxOverflowDelayedCoRoutineList;
262
                        pxOverflowDelayedCoRoutineList = pxTemp;
263
                }
264
 
265
                /* See if this tick has made a timeout expire. */
266
                while( ( pxCRCB = ( corCRCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedCoRoutineList ) ) != NULL )
267
                {
268
                        if( xCoRoutineTickCount < listGET_LIST_ITEM_VALUE( &( pxCRCB->xGenericListItem ) ) )
269
                        {
270
                                /* Timeout not yet expired. */
271
                                break;
272
                        }
273
 
274
                        portDISABLE_INTERRUPTS();
275
                        {
276
                                /* The event could have occurred just before this critical
277
                                section.  If this is the case then the generic list item will
278
                                have been moved to the pending ready list and the following
279
                                line is still valid.  Also the pvContainer parameter will have
280
                                been set to NULL so the following lines are also valid. */
281
                                vListRemove( &( pxCRCB->xGenericListItem ) );
282
 
283
                                /* Is the co-routine waiting on an event also? */
284
                                if( pxCRCB->xEventListItem.pvContainer )
285
                                {
286
                                        vListRemove( &( pxCRCB->xEventListItem ) );
287
                                }
288
                        }
289
                        portENABLE_INTERRUPTS();
290
 
291
                        prvAddCoRoutineToReadyQueue( pxCRCB );
292
                }
293
        }
294
 
295
        xLastTickCount = xCoRoutineTickCount;
296
}
297
/*-----------------------------------------------------------*/
298
 
299
void vCoRoutineSchedule( void )
300
{
301
        /* See if any co-routines readied by events need moving to the ready lists. */
302
        prvCheckPendingReadyList();
303
 
304
        /* See if any delayed co-routines have timed out. */
305
        prvCheckDelayedList();
306
 
307
        /* Find the highest priority queue that contains ready co-routines. */
308
        while( listLIST_IS_EMPTY( &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) ) )
309
        {
310
                if( uxTopCoRoutineReadyPriority == 0 )
311
                {
312
                        /* No more co-routines to check. */
313
                        return;
314
                }
315
                --uxTopCoRoutineReadyPriority;
316
        }
317
 
318
        /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the co-routines
319
         of the same priority get an equal share of the processor time. */
320
        listGET_OWNER_OF_NEXT_ENTRY( pxCurrentCoRoutine, &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) );
321
 
322
        /* Call the co-routine. */
323
        ( pxCurrentCoRoutine->pxCoRoutineFunction )( pxCurrentCoRoutine, pxCurrentCoRoutine->uxIndex );
324
 
325
        return;
326
}
327
/*-----------------------------------------------------------*/
328
 
329
static void prvInitialiseCoRoutineLists( void )
330
{
331
unsigned portBASE_TYPE uxPriority;
332
 
333
        for( uxPriority = 0; uxPriority < configMAX_CO_ROUTINE_PRIORITIES; uxPriority++ )
334
        {
335
                vListInitialise( ( xList * ) &( pxReadyCoRoutineLists[ uxPriority ] ) );
336
        }
337
 
338
        vListInitialise( ( xList * ) &xDelayedCoRoutineList1 );
339
        vListInitialise( ( xList * ) &xDelayedCoRoutineList2 );
340
        vListInitialise( ( xList * ) &xPendingReadyCoRoutineList );
341
 
342
        /* Start with pxDelayedCoRoutineList using list1 and the
343
        pxOverflowDelayedCoRoutineList using list2. */
344
        pxDelayedCoRoutineList = &xDelayedCoRoutineList1;
345
        pxOverflowDelayedCoRoutineList = &xDelayedCoRoutineList2;
346
}
347
/*-----------------------------------------------------------*/
348
 
349
signed portBASE_TYPE xCoRoutineRemoveFromEventList( const xList *pxEventList )
350
{
351
corCRCB *pxUnblockedCRCB;
352
signed portBASE_TYPE xReturn;
353
 
354
        /* This function is called from within an interrupt.  It can only access
355
        event lists and the pending ready list. */
356
        pxUnblockedCRCB = ( corCRCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
357
        vListRemove( &( pxUnblockedCRCB->xEventListItem ) );
358
        vListInsertEnd( ( xList * ) &( xPendingReadyCoRoutineList ), &( pxUnblockedCRCB->xEventListItem ) );
359
 
360
        if( pxUnblockedCRCB->uxPriority >= pxCurrentCoRoutine->uxPriority )
361
        {
362
                xReturn = pdTRUE;
363
        }
364
        else
365
        {
366
                xReturn = pdFALSE;
367
        }
368
 
369
        return xReturn;
370
}
371
 

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