| 1 |
606 |
jeremybenn |
/*
|
| 2 |
|
|
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 |
|
|
* *
|
| 23 |
|
|
***************************************************************************
|
| 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.
|
| 33 |
|
|
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
|
| 40 |
|
|
FreeRTOS WEB site.
|
| 41 |
|
|
|
| 42 |
|
|
1 tab == 4 spaces!
|
| 43 |
|
|
|
| 44 |
|
|
http://www.FreeRTOS.org - Documentation, latest information, license and
|
| 45 |
|
|
contact details.
|
| 46 |
|
|
|
| 47 |
|
|
http://www.SafeRTOS.com - A version that is certified for use in safety
|
| 48 |
|
|
critical systems.
|
| 49 |
|
|
|
| 50 |
|
|
http://www.OpenRTOS.com - Commercial support, development, porting,
|
| 51 |
|
|
licensing and training services.
|
| 52 |
|
|
*/
|
| 53 |
|
|
|
| 54 |
|
|
/**
|
| 55 |
|
|
* Creates two sets of two tasks. The tasks within a set share a variable, access
|
| 56 |
|
|
* to which is guarded by a semaphore.
|
| 57 |
|
|
*
|
| 58 |
|
|
* Each task starts by attempting to obtain the semaphore. On obtaining a
|
| 59 |
|
|
* semaphore a task checks to ensure that the guarded variable has an expected
|
| 60 |
|
|
* value. It then clears the variable to zero before counting it back up to the
|
| 61 |
|
|
* expected value in increments of 1. After each increment the variable is checked
|
| 62 |
|
|
* to ensure it contains the value to which it was just set. When the starting
|
| 63 |
|
|
* value is again reached the task releases the semaphore giving the other task in
|
| 64 |
|
|
* the set a chance to do exactly the same thing. The starting value is high
|
| 65 |
|
|
* enough to ensure that a tick is likely to occur during the incrementing loop.
|
| 66 |
|
|
*
|
| 67 |
|
|
* An error is flagged if at any time during the process a shared variable is
|
| 68 |
|
|
* found to have a value other than that expected. Such an occurrence would
|
| 69 |
|
|
* suggest an error in the mutual exclusion mechanism by which access to the
|
| 70 |
|
|
* variable is restricted.
|
| 71 |
|
|
*
|
| 72 |
|
|
* The first set of two tasks poll their semaphore. The second set use blocking
|
| 73 |
|
|
* calls.
|
| 74 |
|
|
*
|
| 75 |
|
|
* \page SemTestC semtest.c
|
| 76 |
|
|
* \ingroup DemoFiles
|
| 77 |
|
|
* <HR>
|
| 78 |
|
|
*/
|
| 79 |
|
|
|
| 80 |
|
|
/*
|
| 81 |
|
|
Changes from V1.2.0:
|
| 82 |
|
|
|
| 83 |
|
|
+ The tasks that operate at the idle priority now use a lower expected
|
| 84 |
|
|
count than those running at a higher priority. This prevents the low
|
| 85 |
|
|
priority tasks from signaling an error because they have not been
|
| 86 |
|
|
scheduled enough time for each of them to count the shared variable to
|
| 87 |
|
|
the high value.
|
| 88 |
|
|
|
| 89 |
|
|
Changes from V2.0.0
|
| 90 |
|
|
|
| 91 |
|
|
+ Delay periods are now specified using variables and constants of
|
| 92 |
|
|
portTickType rather than unsigned long.
|
| 93 |
|
|
|
| 94 |
|
|
Changes from V2.1.1
|
| 95 |
|
|
|
| 96 |
|
|
+ The stack size now uses configMINIMAL_STACK_SIZE.
|
| 97 |
|
|
+ String constants made file scope to decrease stack depth on 8051 port.
|
| 98 |
|
|
*/
|
| 99 |
|
|
|
| 100 |
|
|
#include <stdlib.h>
|
| 101 |
|
|
|
| 102 |
|
|
/* Scheduler include files. */
|
| 103 |
|
|
#include "FreeRTOS.h"
|
| 104 |
|
|
#include "task.h"
|
| 105 |
|
|
#include "semphr.h"
|
| 106 |
|
|
|
| 107 |
|
|
/* Demo app include files. */
|
| 108 |
|
|
#include "semtest.h"
|
| 109 |
|
|
#include "print.h"
|
| 110 |
|
|
|
| 111 |
|
|
/* The value to which the shared variables are counted. */
|
| 112 |
|
|
#define semtstBLOCKING_EXPECTED_VALUE ( ( unsigned long ) 0xfff )
|
| 113 |
|
|
#define semtstNON_BLOCKING_EXPECTED_VALUE ( ( unsigned long ) 0xff )
|
| 114 |
|
|
|
| 115 |
|
|
#define semtstSTACK_SIZE configMINIMAL_STACK_SIZE
|
| 116 |
|
|
|
| 117 |
|
|
#define semtstNUM_TASKS ( 4 )
|
| 118 |
|
|
|
| 119 |
|
|
#define semtstDELAY_FACTOR ( ( portTickType ) 10 )
|
| 120 |
|
|
|
| 121 |
|
|
/* The task function as described at the top of the file. */
|
| 122 |
|
|
static void prvSemaphoreTest( void *pvParameters );
|
| 123 |
|
|
|
| 124 |
|
|
/* Structure used to pass parameters to each task. */
|
| 125 |
|
|
typedef struct SEMAPHORE_PARAMETERS
|
| 126 |
|
|
{
|
| 127 |
|
|
xSemaphoreHandle xSemaphore;
|
| 128 |
|
|
volatile unsigned long *pulSharedVariable;
|
| 129 |
|
|
portTickType xBlockTime;
|
| 130 |
|
|
} xSemaphoreParameters;
|
| 131 |
|
|
|
| 132 |
|
|
/* Variables used to check that all the tasks are still running without errors. */
|
| 133 |
|
|
static volatile short sCheckVariables[ semtstNUM_TASKS ] = { 0 };
|
| 134 |
|
|
static volatile short sNextCheckVariable = 0;
|
| 135 |
|
|
|
| 136 |
|
|
/* Strings to print if USE_STDIO is defined. */
|
| 137 |
|
|
const char * const pcPollingSemaphoreTaskError = "Guarded shared variable in unexpected state.\r\n";
|
| 138 |
|
|
const char * const pcSemaphoreTaskStart = "Guarded shared variable task started.\r\n";
|
| 139 |
|
|
|
| 140 |
|
|
/*-----------------------------------------------------------*/
|
| 141 |
|
|
|
| 142 |
|
|
void vStartSemaphoreTasks( unsigned portBASE_TYPE uxPriority )
|
| 143 |
|
|
{
|
| 144 |
|
|
xSemaphoreParameters *pxFirstSemaphoreParameters, *pxSecondSemaphoreParameters;
|
| 145 |
|
|
const portTickType xBlockTime = ( portTickType ) 100;
|
| 146 |
|
|
|
| 147 |
|
|
/* Create the structure used to pass parameters to the first two tasks. */
|
| 148 |
|
|
pxFirstSemaphoreParameters = ( xSemaphoreParameters * ) pvPortMalloc( sizeof( xSemaphoreParameters ) );
|
| 149 |
|
|
|
| 150 |
|
|
if( pxFirstSemaphoreParameters != NULL )
|
| 151 |
|
|
{
|
| 152 |
|
|
/* Create the semaphore used by the first two tasks. */
|
| 153 |
|
|
vSemaphoreCreateBinary( pxFirstSemaphoreParameters->xSemaphore );
|
| 154 |
|
|
|
| 155 |
|
|
if( pxFirstSemaphoreParameters->xSemaphore != NULL )
|
| 156 |
|
|
{
|
| 157 |
|
|
/* Create the variable which is to be shared by the first two tasks. */
|
| 158 |
|
|
pxFirstSemaphoreParameters->pulSharedVariable = ( unsigned long * ) pvPortMalloc( sizeof( unsigned long ) );
|
| 159 |
|
|
|
| 160 |
|
|
/* Initialise the share variable to the value the tasks expect. */
|
| 161 |
|
|
*( pxFirstSemaphoreParameters->pulSharedVariable ) = semtstNON_BLOCKING_EXPECTED_VALUE;
|
| 162 |
|
|
|
| 163 |
|
|
/* The first two tasks do not block on semaphore calls. */
|
| 164 |
|
|
pxFirstSemaphoreParameters->xBlockTime = ( portTickType ) 0;
|
| 165 |
|
|
|
| 166 |
|
|
/* Spawn the first two tasks. As they poll they operate at the idle priority. */
|
| 167 |
|
|
xTaskCreate( prvSemaphoreTest, "PolSEM1", semtstSTACK_SIZE, ( void * ) pxFirstSemaphoreParameters, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
|
| 168 |
|
|
xTaskCreate( prvSemaphoreTest, "PolSEM2", semtstSTACK_SIZE, ( void * ) pxFirstSemaphoreParameters, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
|
| 169 |
|
|
}
|
| 170 |
|
|
}
|
| 171 |
|
|
|
| 172 |
|
|
/* Do exactly the same to create the second set of tasks, only this time
|
| 173 |
|
|
provide a block time for the semaphore calls. */
|
| 174 |
|
|
pxSecondSemaphoreParameters = ( xSemaphoreParameters * ) pvPortMalloc( sizeof( xSemaphoreParameters ) );
|
| 175 |
|
|
if( pxSecondSemaphoreParameters != NULL )
|
| 176 |
|
|
{
|
| 177 |
|
|
vSemaphoreCreateBinary( pxSecondSemaphoreParameters->xSemaphore );
|
| 178 |
|
|
|
| 179 |
|
|
if( pxSecondSemaphoreParameters->xSemaphore != NULL )
|
| 180 |
|
|
{
|
| 181 |
|
|
pxSecondSemaphoreParameters->pulSharedVariable = ( unsigned long * ) pvPortMalloc( sizeof( unsigned long ) );
|
| 182 |
|
|
*( pxSecondSemaphoreParameters->pulSharedVariable ) = semtstBLOCKING_EXPECTED_VALUE;
|
| 183 |
|
|
pxSecondSemaphoreParameters->xBlockTime = xBlockTime / portTICK_RATE_MS;
|
| 184 |
|
|
|
| 185 |
|
|
xTaskCreate( prvSemaphoreTest, "BlkSEM1", semtstSTACK_SIZE, ( void * ) pxSecondSemaphoreParameters, uxPriority, ( xTaskHandle * ) NULL );
|
| 186 |
|
|
xTaskCreate( prvSemaphoreTest, "BlkSEM2", semtstSTACK_SIZE, ( void * ) pxSecondSemaphoreParameters, uxPriority, ( xTaskHandle * ) NULL );
|
| 187 |
|
|
}
|
| 188 |
|
|
}
|
| 189 |
|
|
}
|
| 190 |
|
|
/*-----------------------------------------------------------*/
|
| 191 |
|
|
|
| 192 |
|
|
static void prvSemaphoreTest( void *pvParameters )
|
| 193 |
|
|
{
|
| 194 |
|
|
xSemaphoreParameters *pxParameters;
|
| 195 |
|
|
volatile unsigned long *pulSharedVariable, ulExpectedValue;
|
| 196 |
|
|
unsigned long ulCounter;
|
| 197 |
|
|
short sError = pdFALSE, sCheckVariableToUse;
|
| 198 |
|
|
|
| 199 |
|
|
/* See which check variable to use. sNextCheckVariable is not semaphore
|
| 200 |
|
|
protected! */
|
| 201 |
|
|
portENTER_CRITICAL();
|
| 202 |
|
|
sCheckVariableToUse = sNextCheckVariable;
|
| 203 |
|
|
sNextCheckVariable++;
|
| 204 |
|
|
portEXIT_CRITICAL();
|
| 205 |
|
|
|
| 206 |
|
|
/* Queue a message for printing to say the task has started. */
|
| 207 |
|
|
vPrintDisplayMessage( &pcSemaphoreTaskStart );
|
| 208 |
|
|
|
| 209 |
|
|
/* A structure is passed in as the parameter. This contains the shared
|
| 210 |
|
|
variable being guarded. */
|
| 211 |
|
|
pxParameters = ( xSemaphoreParameters * ) pvParameters;
|
| 212 |
|
|
pulSharedVariable = pxParameters->pulSharedVariable;
|
| 213 |
|
|
|
| 214 |
|
|
/* If we are blocking we use a much higher count to ensure loads of context
|
| 215 |
|
|
switches occur during the count. */
|
| 216 |
|
|
if( pxParameters->xBlockTime > ( portTickType ) 0 )
|
| 217 |
|
|
{
|
| 218 |
|
|
ulExpectedValue = semtstBLOCKING_EXPECTED_VALUE;
|
| 219 |
|
|
}
|
| 220 |
|
|
else
|
| 221 |
|
|
{
|
| 222 |
|
|
ulExpectedValue = semtstNON_BLOCKING_EXPECTED_VALUE;
|
| 223 |
|
|
}
|
| 224 |
|
|
|
| 225 |
|
|
for( ;; )
|
| 226 |
|
|
{
|
| 227 |
|
|
/* Try to obtain the semaphore. */
|
| 228 |
|
|
if( xSemaphoreTake( pxParameters->xSemaphore, pxParameters->xBlockTime ) == pdPASS )
|
| 229 |
|
|
{
|
| 230 |
|
|
/* We have the semaphore and so expect any other tasks using the
|
| 231 |
|
|
shared variable to have left it in the state we expect to find
|
| 232 |
|
|
it. */
|
| 233 |
|
|
if( *pulSharedVariable != ulExpectedValue )
|
| 234 |
|
|
{
|
| 235 |
|
|
vPrintDisplayMessage( &pcPollingSemaphoreTaskError );
|
| 236 |
|
|
sError = pdTRUE;
|
| 237 |
|
|
}
|
| 238 |
|
|
|
| 239 |
|
|
/* Clear the variable, then count it back up to the expected value
|
| 240 |
|
|
before releasing the semaphore. Would expect a context switch or
|
| 241 |
|
|
two during this time. */
|
| 242 |
|
|
for( ulCounter = ( unsigned long ) 0; ulCounter <= ulExpectedValue; ulCounter++ )
|
| 243 |
|
|
{
|
| 244 |
|
|
*pulSharedVariable = ulCounter;
|
| 245 |
|
|
if( *pulSharedVariable != ulCounter )
|
| 246 |
|
|
{
|
| 247 |
|
|
if( sError == pdFALSE )
|
| 248 |
|
|
{
|
| 249 |
|
|
vPrintDisplayMessage( &pcPollingSemaphoreTaskError );
|
| 250 |
|
|
}
|
| 251 |
|
|
sError = pdTRUE;
|
| 252 |
|
|
}
|
| 253 |
|
|
}
|
| 254 |
|
|
|
| 255 |
|
|
/* Release the semaphore, and if no errors have occurred increment the check
|
| 256 |
|
|
variable. */
|
| 257 |
|
|
if( xSemaphoreGive( pxParameters->xSemaphore ) == pdFALSE )
|
| 258 |
|
|
{
|
| 259 |
|
|
vPrintDisplayMessage( &pcPollingSemaphoreTaskError );
|
| 260 |
|
|
sError = pdTRUE;
|
| 261 |
|
|
}
|
| 262 |
|
|
|
| 263 |
|
|
if( sError == pdFALSE )
|
| 264 |
|
|
{
|
| 265 |
|
|
if( sCheckVariableToUse < semtstNUM_TASKS )
|
| 266 |
|
|
{
|
| 267 |
|
|
( sCheckVariables[ sCheckVariableToUse ] )++;
|
| 268 |
|
|
}
|
| 269 |
|
|
}
|
| 270 |
|
|
|
| 271 |
|
|
/* If we have a block time then we are running at a priority higher
|
| 272 |
|
|
than the idle priority. This task takes a long time to complete
|
| 273 |
|
|
a cycle (deliberately so to test the guarding) so will be starving
|
| 274 |
|
|
out lower priority tasks. Block for some time to allow give lower
|
| 275 |
|
|
priority tasks some processor time. */
|
| 276 |
|
|
vTaskDelay( pxParameters->xBlockTime * semtstDELAY_FACTOR );
|
| 277 |
|
|
}
|
| 278 |
|
|
else
|
| 279 |
|
|
{
|
| 280 |
|
|
if( pxParameters->xBlockTime == ( portTickType ) 0 )
|
| 281 |
|
|
{
|
| 282 |
|
|
/* We have not got the semaphore yet, so no point using the
|
| 283 |
|
|
processor. We are not blocking when attempting to obtain the
|
| 284 |
|
|
semaphore. */
|
| 285 |
|
|
taskYIELD();
|
| 286 |
|
|
}
|
| 287 |
|
|
}
|
| 288 |
|
|
}
|
| 289 |
|
|
}
|
| 290 |
|
|
/*-----------------------------------------------------------*/
|
| 291 |
|
|
|
| 292 |
|
|
/* This is called to check that all the created tasks are still running. */
|
| 293 |
|
|
portBASE_TYPE xAreSemaphoreTasksStillRunning( void )
|
| 294 |
|
|
{
|
| 295 |
|
|
static short sLastCheckVariables[ semtstNUM_TASKS ] = { 0 };
|
| 296 |
|
|
portBASE_TYPE xTask, xReturn = pdTRUE;
|
| 297 |
|
|
|
| 298 |
|
|
for( xTask = 0; xTask < semtstNUM_TASKS; xTask++ )
|
| 299 |
|
|
{
|
| 300 |
|
|
if( sLastCheckVariables[ xTask ] == sCheckVariables[ xTask ] )
|
| 301 |
|
|
{
|
| 302 |
|
|
xReturn = pdFALSE;
|
| 303 |
|
|
}
|
| 304 |
|
|
|
| 305 |
|
|
sLastCheckVariables[ xTask ] = sCheckVariables[ xTask ];
|
| 306 |
|
|
}
|
| 307 |
|
|
|
| 308 |
|
|
return xReturn;
|
| 309 |
|
|
}
|
| 310 |
|
|
|
| 311 |
|
|
|
