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1 /*

4

5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

6

7 This file is part of the FreeRTOS distribution.

8

9 FreeRTOS is free software; you can redistribute it and/or modify it under

10 the terms of the GNU General Public License (version 2) as published by the

11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.

12

13 ***************************************************************************

14 >>! NOTE: The modification to the GPL is included to allow you to !<<

15 >>! distribute a combined work that includes FreeRTOS without being !<<

16 >>! obliged to provide the source code for proprietary components !<<

17 >>! outside of the FreeRTOS kernel. !<<

18 ***************************************************************************

19

20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY

21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

22 FOR A PARTICULAR PURPOSE. Full license text is available on the following

23 link: http://www.freertos.org/a00114.html

24

25 ***************************************************************************

26 * *

27 * FreeRTOS provides completely free yet professionally developed, *

28 * robust, strictly quality controlled, supported, and cross *

29 * platform software that is more than just the market leader, it *

30 * is the industry's de facto standard. *

31 * *

32 * Help yourself get started quickly while simultaneously helping *

33 * to support the FreeRTOS project by purchasing a FreeRTOS *

34 * tutorial book, reference manual, or both: *

35 * http://www.FreeRTOS.org/Documentation *

36 * *

37 ***************************************************************************

38

39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading

40 the FAQ page "My application does not run, what could be wrong?". Have you

41 defined configASSERT()?

42

43 http://www.FreeRTOS.org/support - In return for receiving this top quality

44 embedded software for free we request you assist our global community by

45 participating in the support forum.

46

47 http://www.FreeRTOS.org/training - Investing in training allows your team to

48 be as productive as possible as early as possible. Now you can receive

49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers

50 Ltd, and the world's leading authority on the world's leading RTOS.

51

52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,

53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS

54 compatible FAT file system, and our tiny thread aware UDP/IP stack.

55

56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.

57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

58

59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High

60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS

61 licenses offer ticketed support, indemnification and commercial middleware.

62

63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety

64 engineered and independently SIL3 certified version for use in safety and

65 mission critical applications that require provable dependability.

66

67 1 tab == 4 spaces!

68 */

69

70 /**

71 * Creates six tasks that operate on three queues as follows:

72 *

73 * The first two tasks send and receive an incrementing number to/from a queue.

74 * One task acts as a producer and the other as the consumer. The consumer is a

75 * higher priority than the producer and is set to block on queue reads. The queue

76 * only has space for one item - as soon as the producer posts a message on the

77 * queue the consumer will unblock, pre-empt the producer, and remove the item.

78 *

79 * The second two tasks work the other way around. Again the queue used only has

80 * enough space for one item. This time the consumer has a lower priority than the

81 * producer. The producer will try to post on the queue blocking when the queue is

82 * full. When the consumer wakes it will remove the item from the queue, causing

83 * the producer to unblock, pre-empt the consumer, and immediately re-fill the

84 * queue.

85 *

86 * The last two tasks use the same queue producer and consumer functions. This time the queue has

87 * enough space for lots of items and the tasks operate at the same priority. The

88 * producer will execute, placing items into the queue. The consumer will start

89 * executing when either the queue becomes full (causing the producer to block) or

90 * a context switch occurs (tasks of the same priority will time slice).

91 *

92 * \page BlockQC blockQ.c

93 * \ingroup DemoFiles

94 * <HR>

95 */

96

97 /*

98 Changes from V1.00:

99

100 + Reversed the priority and block times of the second two demo tasks so

101 they operate as per the description above.

102

103 Changes from V2.0.0

104

105 + Delay periods are now specified using variables and constants of

106 TickType_t rather than unsigned long.

107

108 Changes from V4.0.2

109

110 + The second set of tasks were created the wrong way around. This has been

111 corrected.

112 */

113

114

115 #include <stdlib.h>

116

117 /* Scheduler include files. */

118 #include "FreeRTOS.h"

119 #include "task.h"

120 #include "queue.h"

121

122 /* Demo program include files. */

123 #include "BlockQ.h"

124 #include "print.h"

125

126 #define blckqSTACK_SIZE ( ( unsigned short ) configMINIMAL_STACK_SIZE )

127 #define blckqNUM_TASK_SETS ( 3 )

128

129 /* Structure used to pass parameters to the blocking queue tasks. */

130 typedef struct BLOCKING_QUEUE_PARAMETERS

131 {

132 QueueHandle_t xQueue; /*< The queue to be used by the task. */

133 TickType_t xBlockTime; /*< The block time to use on queue reads/writes. */

134 volatile short *psCheckVariable; /*< Incremented on each successful cycle to check the task is still running. */

135 } xBlockingQueueParameters;

136

137 /* Task function that creates an incrementing number and posts it on a queue. */

138 static void vBlockingQueueProducer( void *pvParameters );

139

140 /* Task function that removes the incrementing number from a queue and checks that

141 it is the expected number. */

142 static void vBlockingQueueConsumer( void *pvParameters );

143

144 /* Variables which are incremented each time an item is removed from a queue, and

145 found to be the expected value.

146 These are used to check that the tasks are still running. */

147 static volatile short sBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };

148

149 /* Variable which are incremented each time an item is posted on a queue. These

150 are used to check that the tasks are still running. */

151 static volatile short sBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };

152

153 /*-----------------------------------------------------------*/

154

155 void vStartBlockingQueueTasks( unsigned portBASE_TYPE uxPriority )

156 {

157 xBlockingQueueParameters *pxQueueParameters1, *pxQueueParameters2;

158 xBlockingQueueParameters *pxQueueParameters3, *pxQueueParameters4;

159 xBlockingQueueParameters *pxQueueParameters5, *pxQueueParameters6;

160 const unsigned portBASE_TYPE uxQueueSize1 = 1, uxQueueSize5 = 5;

161 const TickType_t xBlockTime = ( TickType_t ) 1000 / portTICK_PERIOD_MS;

162 const TickType_t xDontBlock = ( TickType_t ) 0;

163

164 /* Create the first two tasks as described at the top of the file. */

165

166 /* First create the structure used to pass parameters to the consumer tasks. */

167 pxQueueParameters1 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );

168

169 /* Create the queue used by the first two tasks to pass the incrementing number.

170 Pass a pointer to the queue in the parameter structure. */

171 pxQueueParameters1->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );

172

173 /* The consumer is created first so gets a block time as described above. */

174 pxQueueParameters1->xBlockTime = xBlockTime;

175

176 /* Pass in the variable that this task is going to increment so we can check it

177 is still running. */

178 pxQueueParameters1->psCheckVariable = &( sBlockingConsumerCount[ 0 ] );

179

180 /* Create the structure used to pass parameters to the producer task. */

181 pxQueueParameters2 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );

182

183 /* Pass the queue to this task also, using the parameter structure. */

184 pxQueueParameters2->xQueue = pxQueueParameters1->xQueue;

185

186 /* The producer is not going to block - as soon as it posts the consumer will

187 wake and remove the item so the producer should always have room to post. */

188 pxQueueParameters2->xBlockTime = xDontBlock;

189

190 /* Pass in the variable that this task is going to increment so we can check

191 it is still running. */

192 pxQueueParameters2->psCheckVariable = &( sBlockingProducerCount[ 0 ] );

193

194

195 /* Note the producer has a lower priority than the consumer when the tasks are

196 spawned. */

197 xTaskCreate( vBlockingQueueConsumer, "QConsB1", blckqSTACK_SIZE, ( void * ) pxQueueParameters1, uxPriority, NULL );

198 xTaskCreate( vBlockingQueueProducer, "QProdB2", blckqSTACK_SIZE, ( void * ) pxQueueParameters2, tskIDLE_PRIORITY, NULL );

199

200

201

202 /* Create the second two tasks as described at the top of the file. This uses

203 the same mechanism but reverses the task priorities. */

204

205 pxQueueParameters3 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );

206 pxQueueParameters3->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );

207 pxQueueParameters3->xBlockTime = xDontBlock;

208 pxQueueParameters3->psCheckVariable = &( sBlockingProducerCount[ 1 ] );

209

210 pxQueueParameters4 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );

211 pxQueueParameters4->xQueue = pxQueueParameters3->xQueue;

212 pxQueueParameters4->xBlockTime = xBlockTime;

213 pxQueueParameters4->psCheckVariable = &( sBlockingConsumerCount[ 1 ] );

214

215 xTaskCreate( vBlockingQueueProducer, "QProdB3", blckqSTACK_SIZE, ( void * ) pxQueueParameters3, tskIDLE_PRIORITY, NULL );

216 xTaskCreate( vBlockingQueueConsumer, "QConsB4", blckqSTACK_SIZE, ( void * ) pxQueueParameters4, uxPriority, NULL );

217

218

219

220 /* Create the last two tasks as described above. The mechanism is again just

221 the same. This time both parameter structures are given a block time. */

222 pxQueueParameters5 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );

223 pxQueueParameters5->xQueue = xQueueCreate( uxQueueSize5, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );

224 pxQueueParameters5->xBlockTime = xBlockTime;

225 pxQueueParameters5->psCheckVariable = &( sBlockingProducerCount[ 2 ] );

226

227 pxQueueParameters6 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );

228 pxQueueParameters6->xQueue = pxQueueParameters5->xQueue;

229 pxQueueParameters6->xBlockTime = xBlockTime;

230 pxQueueParameters6->psCheckVariable = &( sBlockingConsumerCount[ 2 ] );

231

232 xTaskCreate( vBlockingQueueProducer, "QProdB5", blckqSTACK_SIZE, ( void * ) pxQueueParameters5, tskIDLE_PRIORITY, NULL );

233 xTaskCreate( vBlockingQueueConsumer, "QConsB6", blckqSTACK_SIZE, ( void * ) pxQueueParameters6, tskIDLE_PRIORITY, NULL );

234 }

235 /*-----------------------------------------------------------*/

236

237 static void vBlockingQueueProducer( void *pvParameters )

238 {

239 unsigned short usValue = 0;

240 xBlockingQueueParameters *pxQueueParameters;

241 const char * const pcTaskStartMsg = "Blocking queue producer started.\r\n";

242 const char * const pcTaskErrorMsg = "Could not post on blocking queue\r\n";

243 short sErrorEverOccurred = pdFALSE;

244

245 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;

246

247 /* Queue a message for printing to say the task has started. */

248 vPrintDisplayMessage( &pcTaskStartMsg );

249

250 for( ;; )

251 {

252 if( xQueueSendToBack( pxQueueParameters->xQueue, ( void * ) &usValue, pxQueueParameters->xBlockTime ) != pdPASS )

253 {

254 vPrintDisplayMessage( &pcTaskErrorMsg );

255 sErrorEverOccurred = pdTRUE;

256 }

257 else

258 {

259 /* We have successfully posted a message, so increment the variable

260 used to check we are still running. */

261 if( sErrorEverOccurred == pdFALSE )

262 {

263 ( *pxQueueParameters->psCheckVariable )++;

264 }

265

266 /* Increment the variable we are going to post next time round. The

267 consumer will expect the numbers to follow in numerical order. */

268 ++usValue;

269 }

270 }

271 }

272 /*-----------------------------------------------------------*/

273

274 static void vBlockingQueueConsumer( void *pvParameters )

275 {

276 unsigned short usData, usExpectedValue = 0;

277 xBlockingQueueParameters *pxQueueParameters;

278 const char * const pcTaskStartMsg = "Blocking queue consumer started.\r\n";

279 const char * const pcTaskErrorMsg = "Incorrect value received on blocking queue.\r\n";

280 short sErrorEverOccurred = pdFALSE;

281

282 /* Queue a message for printing to say the task has started. */

283 vPrintDisplayMessage( &pcTaskStartMsg );

284

285 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;

286

287 for( ;; )

288 {

289 if( xQueueReceive( pxQueueParameters->xQueue, &usData, pxQueueParameters->xBlockTime ) == pdPASS )

290 {

291 if( usData != usExpectedValue )

292 {

293 vPrintDisplayMessage( &pcTaskErrorMsg );

294

295 /* Catch-up. */

296 usExpectedValue = usData;

297

298 sErrorEverOccurred = pdTRUE;

299 }

300 else

301 {

302 /* We have successfully received a message, so increment the

303 variable used to check we are still running. */

304 if( sErrorEverOccurred == pdFALSE )

305 {

306 ( *pxQueueParameters->psCheckVariable )++;

307 }

308

309 /* Increment the value we expect to remove from the queue next time

310 round. */

311 ++usExpectedValue;

312 }

313 }

314 }

315 }

316 /*-----------------------------------------------------------*/

317

318 /* This is called to check that all the created tasks are still running. */

319 portBASE_TYPE xAreBlockingQueuesStillRunning( void )

320 {

321 static short sLastBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };

322 static short sLastBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };

323 portBASE_TYPE xReturn = pdPASS, xTasks;

324

325 /* Not too worried about mutual exclusion on these variables as they are 16

326 bits and we are only reading them. We also only care to see if they have

327 changed or not.

328

329 Loop through each check variable and return pdFALSE if any are found not

330 to have changed since the last call. */

331

332 for( xTasks = 0; xTasks < blckqNUM_TASK_SETS; xTasks++ )

333 {

334 if( sBlockingConsumerCount[ xTasks ] == sLastBlockingConsumerCount[ xTasks ] )

335 {

336 xReturn = pdFALSE;

337 }

338 sLastBlockingConsumerCount[ xTasks ] = sBlockingConsumerCount[ xTasks ];

339

340

341 if( sBlockingProducerCount[ xTasks ] == sLastBlockingProducerCount[ xTasks ] )

342 {

343 xReturn = pdFALSE;

344 }

345 sLastBlockingProducerCount[ xTasks ] = sBlockingProducerCount[ xTasks ];

346 }

347

348 return xReturn;

349 }

350