/*
FreeRTOS.org V4.2.1 - Copyright (C) 2003-2007 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS.org is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FreeRTOS.org; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS.org, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
See http://www.FreeRTOS.org for documentation, latest information, license
and contact details. Please ensure to read the configuration and relevant
port sections of the online documentation.
Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
with commercial development and support options.
***************************************************************************
*/
#ifndef CO_ROUTINE_H
#define CO_ROUTINE_H
#include "list.h"
/* Used to hide the implementation of the co-routine control block. The
control block structure however has to be included in the header due to
the macro implementation of the co-routine functionality. */
typedef void *xCoRoutineHandle;
/* Defines the prototype to which co-routine functions must conform. */
typedef void (*crCOROUTINE_CODE) (xCoRoutineHandle, unsigned portBASE_TYPE);
typedef struct corCoRoutineControlBlock
{
crCOROUTINE_CODE pxCoRoutineFunction;
xListItem xGenericListItem; /*< List item used to place the CRCB in ready and blocked queues. */
xListItem xEventListItem; /*< List item used to place the CRCB in event lists. */
unsigned portBASE_TYPE uxPriority; /*< The priority of the co-routine in relation to other co-routines. */
unsigned portBASE_TYPE uxIndex; /*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */
unsigned portSHORT uxState; /*< Used internally by the co-routine implementation. */
} corCRCB; /* Co-routine control block. Note must be identical in size down to uxPriority with tskTCB. */
/**
* croutine. h
*
portBASE_TYPE xCoRoutineCreate(
crCOROUTINE_CODE pxCoRoutineCode,
unsigned portBASE_TYPE uxPriority,
unsigned portBASE_TYPE uxIndex
);
*
* Create a new co-routine and add it to the list of co-routines that are
* ready to run.
*
* @param pxCoRoutineCode Pointer to the co-routine function. Co-routine
* functions require special syntax - see the co-routine section of the WEB
* documentation for more information.
*
* @param uxPriority The priority with respect to other co-routines at which
* the co-routine will run.
*
* @param uxIndex Used to distinguish between different co-routines that
* execute the same function. See the example below and the co-routine section
* of the WEB documentation for further information.
*
* @return pdPASS if the co-routine was successfully created and added to a ready
* list, otherwise an error code defined with ProjDefs.h.
*
* Example usage:
// Co-routine to be created.
void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
// This may not be necessary for const variables.
static const char cLedToFlash[ 2 ] = { 5, 6 };
static const portTickType xTimeToDelay[ 2 ] = { 200, 400 };
// Must start every co-routine with a call to crSTART();
crSTART( xHandle );
for( ;; )
{
// This co-routine just delays for a fixed period, then toggles
// an LED. Two co-routines are created using this function, so
// the uxIndex parameter is used to tell the co-routine which
// LED to flash and how long to delay. This assumes xQueue has
// already been created.
vParTestToggleLED( cLedToFlash[ uxIndex ] );
crDELAY( xHandle, uxFlashRates[ uxIndex ] );
}
// Must end every co-routine with a call to crEND();
crEND();
}
// Function that creates two co-routines.
void vOtherFunction( void )
{
unsigned char ucParameterToPass;
xTaskHandle xHandle;
// Create two co-routines at priority 0. The first is given index 0
// so (from the code above) toggles LED 5 every 200 ticks. The second
// is given index 1 so toggles LED 6 every 400 ticks.
for( uxIndex = 0; uxIndex < 2; uxIndex++ )
{
xCoRoutineCreate( vFlashCoRoutine, 0, uxIndex );
}
}
* \defgroup xCoRoutineCreate xCoRoutineCreate
* \ingroup Tasks
*/
signed portBASE_TYPE xCoRoutineCreate (crCOROUTINE_CODE pxCoRoutineCode,
unsigned portBASE_TYPE uxPriority,
unsigned portBASE_TYPE uxIndex);
/**
* croutine. h
*
void vCoRoutineSchedule( void );
*
* Run a co-routine.
*
* vCoRoutineSchedule() executes the highest priority co-routine that is able
* to run. The co-routine will execute until it either blocks, yields or is
* preempted by a task. Co-routines execute cooperatively so one
* co-routine cannot be preempted by another, but can be preempted by a task.
*
* If an application comprises of both tasks and co-routines then
* vCoRoutineSchedule should be called from the idle task (in an idle task
* hook).
*
* Example usage:
// This idle task hook will schedule a co-routine each time it is called.
// The rest of the idle task will execute between co-routine calls.
void vApplicationIdleHook( void )
{
vCoRoutineSchedule();
}
// Alternatively, if you do not require any other part of the idle task to
// execute, the idle task hook can call vCoRoutineScheduler() within an
// infinite loop.
void vApplicationIdleHook( void )
{
for( ;; )
{
vCoRoutineSchedule();
}
}
* \defgroup vCoRoutineSchedule vCoRoutineSchedule
* \ingroup Tasks
*/
void vCoRoutineSchedule (void);
/**
* croutine. h
*
crSTART( xCoRoutineHandle xHandle );
*
* This macro MUST always be called at the start of a co-routine function.
*
* Example usage:
// Co-routine to be created.
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
static portLONG ulAVariable;
// Must start every co-routine with a call to crSTART();
crSTART( xHandle );
for( ;; )
{
// Co-routine functionality goes here.
}
// Must end every co-routine with a call to crEND();
crEND();
}
* \defgroup crSTART crSTART
* \ingroup Tasks
*/
#define crSTART( pxCRCB ) switch( ( ( corCRCB * )pxCRCB )->uxState ) { case 0:
/**
* croutine. h
*
crEND();
*
* This macro MUST always be called at the end of a co-routine function.
*
* Example usage:
// Co-routine to be created.
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
static portLONG ulAVariable;
// Must start every co-routine with a call to crSTART();
crSTART( xHandle );
for( ;; )
{
// Co-routine functionality goes here.
}
// Must end every co-routine with a call to crEND();
crEND();
}
* \defgroup crSTART crSTART
* \ingroup Tasks
*/
#define crEND() }
/*
* These macros are intended for internal use by the co-routine implementation
* only. The macros should not be used directly by application writers.
*/
#define crSET_STATE0( xHandle ) ( ( corCRCB * )xHandle)->uxState = (__LINE__ * 2); return; case (__LINE__ * 2):
#define crSET_STATE1( xHandle ) ( ( corCRCB * )xHandle)->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1):
/**
* croutine. h
*
crDELAY( xCoRoutineHandle xHandle, portTickType xTicksToDelay );
*
* Delay a co-routine for a fixed period of time.
*
* crDELAY can only be called from the co-routine function itself - not
* from within a function called by the co-routine function. This is because
* co-routines do not maintain their own stack.
*
* @param xHandle The handle of the co-routine to delay. This is the xHandle
* parameter of the co-routine function.
*
* @param xTickToDelay The number of ticks that the co-routine should delay
* for. The actual amount of time this equates to is defined by
* configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_RATE_MS
* can be used to convert ticks to milliseconds.
*
* Example usage:
// Co-routine to be created.
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
// This may not be necessary for const variables.
// We are to delay for 200ms.
static const xTickType xDelayTime = 200 / portTICK_RATE_MS;
// Must start every co-routine with a call to crSTART();
crSTART( xHandle );
for( ;; )
{
// Delay for 200ms.
crDELAY( xHandle, xDelayTime );
// Do something here.
}
// Must end every co-routine with a call to crEND();
crEND();
}
* \defgroup crDELAY crDELAY
* \ingroup Tasks
*/
#define crDELAY( xHandle, xTicksToDelay ) \
if( xTicksToDelay > 0 ) \
{ \
vCoRoutineAddToDelayedList( xTicksToDelay, NULL ); \
} \
crSET_STATE0( xHandle );
/**
*
crQUEUE_SEND(
xCoRoutineHandle xHandle,
xQueueHandle pxQueue,
void *pvItemToQueue,
portTickType xTicksToWait,
portBASE_TYPE *pxResult
)
*
* The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
* equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
*
* crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
* xQueueSend() and xQueueReceive() can only be used from tasks.
*
* crQUEUE_SEND can only be called from the co-routine function itself - not
* from within a function called by the co-routine function. This is because
* co-routines do not maintain their own stack.
*
* See the co-routine section of the WEB documentation for information on
* passing data between tasks and co-routines and between ISR's and
* co-routines.
*
* @param xHandle The handle of the calling co-routine. This is the xHandle
* parameter of the co-routine function.
*
* @param pxQueue The handle of the queue on which the data will be posted.
* The handle is obtained as the return value when the queue is created using
* the xQueueCreate() API function.
*
* @param pvItemToQueue A pointer to the data being posted onto the queue.
* The number of bytes of each queued item is specified when the queue is
* created. This number of bytes is copied from pvItemToQueue into the queue
* itself.
*
* @param xTickToDelay The number of ticks that the co-routine should block
* to wait for space to become available on the queue, should space not be
* available immediately. The actual amount of time this equates to is defined
* by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
* portTICK_RATE_MS can be used to convert ticks to milliseconds (see example
* below).
*
* @param pxResult The variable pointed to by pxResult will be set to pdPASS if
* data was successfully posted onto the queue, otherwise it will be set to an
* error defined within ProjDefs.h.
*
* Example usage:
// Co-routine function that blocks for a fixed period then posts a number onto
// a queue.
static void prvCoRoutineFlashTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
static portBASE_TYPE xNumberToPost = 0;
static portBASE_TYPE xResult;
// Co-routines must begin with a call to crSTART().
crSTART( xHandle );
for( ;; )
{
// This assumes the queue has already been created.
crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult );
if( xResult != pdPASS )
{
// The message was not posted!
}
// Increment the number to be posted onto the queue.
xNumberToPost++;
// Delay for 100 ticks.
crDELAY( xHandle, 100 );
}
// Co-routines must end with a call to crEND().
crEND();
}
* \defgroup crQUEUE_SEND crQUEUE_SEND
* \ingroup Tasks
*/
#define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult ) \
{ \
*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, xTicksToWait ); \
if( *pxResult == errQUEUE_BLOCKED ) \
{ \
crSET_STATE0( xHandle ); \
*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, 0 ); \
} \
if( *pxResult == errQUEUE_YIELD ) \
{ \
crSET_STATE1( xHandle ); \
*pxResult = pdPASS; \
} \
}
/**
* croutine. h
*
crQUEUE_RECEIVE(
xCoRoutineHandle xHandle,
xQueueHandle pxQueue,
void *pvBuffer,
portTickType xTicksToWait,
portBASE_TYPE *pxResult
)
*
* The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
* equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
*
* crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
* xQueueSend() and xQueueReceive() can only be used from tasks.
*
* crQUEUE_RECEIVE can only be called from the co-routine function itself - not
* from within a function called by the co-routine function. This is because
* co-routines do not maintain their own stack.
*
* See the co-routine section of the WEB documentation for information on
* passing data between tasks and co-routines and between ISR's and
* co-routines.
*
* @param xHandle The handle of the calling co-routine. This is the xHandle
* parameter of the co-routine function.
*
* @param pxQueue The handle of the queue from which the data will be received.
* The handle is obtained as the return value when the queue is created using
* the xQueueCreate() API function.
*
* @param pvBuffer The buffer into which the received item is to be copied.
* The number of bytes of each queued item is specified when the queue is
* created. This number of bytes is copied into pvBuffer.
*
* @param xTickToDelay The number of ticks that the co-routine should block
* to wait for data to become available from the queue, should data not be
* available immediately. The actual amount of time this equates to is defined
* by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
* portTICK_RATE_MS can be used to convert ticks to milliseconds (see the
* crQUEUE_SEND example).
*
* @param pxResult The variable pointed to by pxResult will be set to pdPASS if
* data was successfully retrieved from the queue, otherwise it will be set to
* an error code as defined within ProjDefs.h.
*
* Example usage:
// A co-routine receives the number of an LED to flash from a queue. It
// blocks on the queue until the number is received.
static void prvCoRoutineFlashWorkTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
static portBASE_TYPE xResult;
static unsigned portBASE_TYPE uxLEDToFlash;
// All co-routines must start with a call to crSTART().
crSTART( xHandle );
for( ;; )
{
// Wait for data to become available on the queue.
crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
if( xResult == pdPASS )
{
// We received the LED to flash - flash it!
vParTestToggleLED( uxLEDToFlash );
}
}
crEND();
}
* \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE
* \ingroup Tasks
*/
#define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult ) \
{ \
*pxResult = xQueueCRReceive( pxQueue, pvBuffer, xTicksToWait ); \
if( *pxResult == errQUEUE_BLOCKED ) \
{ \
crSET_STATE0( xHandle ); \
*pxResult = xQueueCRReceive( pxQueue, pvBuffer, 0 ); \
} \
if( *pxResult == errQUEUE_YIELD ) \
{ \
crSET_STATE1( xHandle ); \
*pxResult = pdPASS; \
} \
}
/**
* croutine. h
*
crQUEUE_SEND_FROM_ISR(
xQueueHandle pxQueue,
void *pvItemToQueue,
portBASE_TYPE xCoRoutinePreviouslyWoken
)
*
* The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
* co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
* functions used by tasks.
*
* crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
* pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
* xQueueReceiveFromISR() can only be used to pass data between a task and and
* ISR.
*
* crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue
* that is being used from within a co-routine.
*
* See the co-routine section of the WEB documentation for information on
* passing data between tasks and co-routines and between ISR's and
* co-routines.
*
* @param xQueue The handle to the queue on which the item is to be posted.
*
* @param pvItemToQueue A pointer to the item that is to be placed on the
* queue. The size of the items the queue will hold was defined when the
* queue was created, so this many bytes will be copied from pvItemToQueue
* into the queue storage area.
*
* @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto
* the same queue multiple times from a single interrupt. The first call
* should always pass in pdFALSE. Subsequent calls should pass in
* the value returned from the previous call.
*
* @return pdTRUE if a co-routine was woken by posting onto the queue. This is
* used by the ISR to determine if a context switch may be required following
* the ISR.
*
* Example usage:
// A co-routine that blocks on a queue waiting for characters to be received.
static void vReceivingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
portCHAR cRxedChar;
portBASE_TYPE xResult;
// All co-routines must start with a call to crSTART().
crSTART( xHandle );
for( ;; )
{
// Wait for data to become available on the queue. This assumes the
// queue xCommsRxQueue has already been created!
crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
// Was a character received?
if( xResult == pdPASS )
{
// Process the character here.
}
}
// All co-routines must end with a call to crEND().
crEND();
}
// An ISR that uses a queue to send characters received on a serial port to
// a co-routine.
void vUART_ISR( void )
{
portCHAR cRxedChar;
portBASE_TYPE xCRWokenByPost = pdFALSE;
// We loop around reading characters until there are none left in the UART.
while( UART_RX_REG_NOT_EMPTY() )
{
// Obtain the character from the UART.
cRxedChar = UART_RX_REG;
// Post the character onto a queue. xCRWokenByPost will be pdFALSE
// the first time around the loop. If the post causes a co-routine
// to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE.
// In this manner we can ensure that if more than one co-routine is
// blocked on the queue only one is woken by this ISR no matter how
// many characters are posted to the queue.
xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost );
}
}
* \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR
* \ingroup Tasks
*/
#define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken )
/**
* croutine. h
*
crQUEUE_SEND_FROM_ISR(
xQueueHandle pxQueue,
void *pvBuffer,
portBASE_TYPE * pxCoRoutineWoken
)
*
* The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
* co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
* functions used by tasks.
*
* crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
* pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
* xQueueReceiveFromISR() can only be used to pass data between a task and and
* ISR.
*
* crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data
* from a queue that is being used from within a co-routine (a co-routine
* posted to the queue).
*
* See the co-routine section of the WEB documentation for information on
* passing data between tasks and co-routines and between ISR's and
* co-routines.
*
* @param xQueue The handle to the queue on which the item is to be posted.
*
* @param pvBuffer A pointer to a buffer into which the received item will be
* placed. The size of the items the queue will hold was defined when the
* queue was created, so this many bytes will be copied from the queue into
* pvBuffer.
*
* @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become
* available on the queue. If crQUEUE_RECEIVE_FROM_ISR causes such a
* co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise
* *pxCoRoutineWoken will remain unchanged.
*
* @return pdTRUE an item was successfully received from the queue, otherwise
* pdFALSE.
*
* Example usage:
// A co-routine that posts a character to a queue then blocks for a fixed
// period. The character is incremented each time.
static void vSendingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// cChar holds its value while this co-routine is blocked and must therefore
// be declared static.
static portCHAR cCharToTx = 'a';
portBASE_TYPE xResult;
// All co-routines must start with a call to crSTART().
crSTART( xHandle );
for( ;; )
{
// Send the next character to the queue.
crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult );
if( xResult == pdPASS )
{
// The character was successfully posted to the queue.
}
else
{
// Could not post the character to the queue.
}
// Enable the UART Tx interrupt to cause an interrupt in this
// hypothetical UART. The interrupt will obtain the character
// from the queue and send it.
ENABLE_RX_INTERRUPT();
// Increment to the next character then block for a fixed period.
// cCharToTx will maintain its value across the delay as it is
// declared static.
cCharToTx++;
if( cCharToTx > 'x' )
{
cCharToTx = 'a';
}
crDELAY( 100 );
}
// All co-routines must end with a call to crEND().
crEND();
}
// An ISR that uses a queue to receive characters to send on a UART.
void vUART_ISR( void )
{
portCHAR cCharToTx;
portBASE_TYPE xCRWokenByPost = pdFALSE;
while( UART_TX_REG_EMPTY() )
{
// Are there any characters in the queue waiting to be sent?
// xCRWokenByPost will automatically be set to pdTRUE if a co-routine
// is woken by the post - ensuring that only a single co-routine is
// woken no matter how many times we go around this loop.
if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) )
{
SEND_CHARACTER( cCharToTx );
}
}
}
* \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR
* \ingroup Tasks
*/
#define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( pxQueue, pvBuffer, pxCoRoutineWoken )
/*
* This function is intended for internal use by the co-routine macros only.
* The macro nature of the co-routine implementation requires that the
* prototype appears here. The function should not be used by application
* writers.
*
* Removes the current co-routine from its ready list and places it in the
* appropriate delayed list.
*/
void vCoRoutineAddToDelayedList (portTickType xTicksToDelay,
xList * pxEventList);
/*
* This function is intended for internal use by the queue implementation only.
* The function should not be used by application writers.
*
* Removes the highest priority co-routine from the event list and places it in
* the pending ready list.
*/
signed portBASE_TYPE xCoRoutineRemoveFromEventList (const xList *
pxEventList);
#endif /* CO_ROUTINE_H */