tasks.c

freescale k40/k60 freertos-lwip例程

/*
    FreeRTOS V6.0.4 - Copyright (C) 2010 Real Time Engineers Ltd.

    ***************************************************************************
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    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
    ***NOTE*** The exception to the GPL is included to allow you to distribute
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*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
all the API functions to use the MPU wrappers.  That should only be done when
task.h is included from an application file. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE

#include "FreeRTOS.h"
#include "task.h"
#include "StackMacros.h"

#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE

/*
 * Macro to define the amount of stack available to the idle task.
 */
#define tskIDLE_STACK_SIZE	configMINIMAL_STACK_SIZE

/*
 * Task control block.  A task control block (TCB) is allocated to each task,
 * and stores the context of the task.
 */
typedef struct tskTaskControlBlock
{
	volatile portSTACK_TYPE	*pxTopOfStack;		/*< Points to the location of the last item placed on the tasks stack.  THIS MUST BE THE FIRST MEMBER OF THE STRUCT. */

	#if ( portUSING_MPU_WRAPPERS == 1 )
		xMPU_SETTINGS xMPUSettings;				/*< The MPU settings are defined as part of the port layer.  THIS MUST BE THE SECOND MEMBER OF THE STRUCT. */
	#endif	
	
	xListItem				xGenericListItem;	/*< List item used to place the TCB in ready and blocked queues. */
	xListItem				xEventListItem;		/*< List item used to place the TCB in event lists. */
	unsigned portBASE_TYPE	uxPriority;			/*< The priority of the task where 0 is the lowest priority. */
	portSTACK_TYPE			*pxStack;			/*< Points to the start of the stack. */
	signed char				pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */

	#if ( portSTACK_GROWTH > 0 )
		portSTACK_TYPE *pxEndOfStack;			/*< Used for stack overflow checking on architectures where the stack grows up from low memory. */
	#endif

	#if ( portCRITICAL_NESTING_IN_TCB == 1 )
		unsigned portBASE_TYPE uxCriticalNesting;
	#endif

	#if ( configUSE_TRACE_FACILITY == 1 )
		unsigned portBASE_TYPE	uxTCBNumber;	/*< This is used for tracing the scheduler and making debugging easier only. */
	#endif

	#if ( configUSE_MUTEXES == 1 )
		unsigned portBASE_TYPE uxBasePriority;	/*< The priority last assigned to the task - used by the priority inheritance mechanism. */
	#endif

	#if ( configUSE_APPLICATION_TASK_TAG == 1 )
		pdTASK_HOOK_CODE pxTaskTag;
	#endif

	#if ( configGENERATE_RUN_TIME_STATS == 1 )
		unsigned long ulRunTimeCounter;		/*< Used for calculating how much CPU time each task is utilising. */
	#endif

} tskTCB;


/*
 * Some kernel aware debuggers require data to be viewed to be global, rather
 * than file scope.
 */
#ifdef portREMOVE_STATIC_QUALIFIER
	#define static
#endif

/*lint -e956 */
PRIVILEGED_DATA tskTCB * volatile pxCurrentTCB = NULL;

/* Lists for ready and blocked tasks. --------------------*/

PRIVILEGED_DATA static xList pxReadyTasksLists[ configMAX_PRIORITIES ];	/*< Prioritised ready tasks. */
PRIVILEGED_DATA static xList xDelayedTaskList1;							/*< Delayed tasks. */
PRIVILEGED_DATA static xList xDelayedTaskList2;							/*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
PRIVILEGED_DATA static xList * volatile pxDelayedTaskList ;				/*< Points to the delayed task list currently being used. */
PRIVILEGED_DATA static xList * volatile pxOverflowDelayedTaskList;		/*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */
PRIVILEGED_DATA static xList xPendingReadyList;							/*< Tasks that have been readied while the scheduler was suspended.  They will be moved to the ready queue when the scheduler is resumed. */

#if ( INCLUDE_vTaskDelete == 1 )

	PRIVILEGED_DATA static volatile xList xTasksWaitingTermination;		/*< Tasks that have been deleted - but the their memory not yet freed. */
	PRIVILEGED_DATA static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;

#endif

#if ( INCLUDE_vTaskSuspend == 1 )

	PRIVILEGED_DATA static xList xSuspendedTaskList;					/*< Tasks that are currently suspended. */

#endif

/* File private variables. --------------------------------*/
PRIVILEGED_DATA static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks 	= ( unsigned portBASE_TYPE ) 0;
PRIVILEGED_DATA static volatile portTickType xTickCount 						= ( portTickType ) 0;
PRIVILEGED_DATA static unsigned portBASE_TYPE uxTopUsedPriority	 				= tskIDLE_PRIORITY;
PRIVILEGED_DATA static volatile unsigned portBASE_TYPE uxTopReadyPriority 		= tskIDLE_PRIORITY;
PRIVILEGED_DATA static volatile signed portBASE_TYPE xSchedulerRunning 			= pdFALSE;
PRIVILEGED_DATA static volatile unsigned portBASE_TYPE uxSchedulerSuspended	 	= ( unsigned portBASE_TYPE ) pdFALSE;
PRIVILEGED_DATA static volatile unsigned portBASE_TYPE uxMissedTicks 			= ( unsigned portBASE_TYPE ) 0;
PRIVILEGED_DATA static volatile portBASE_TYPE xMissedYield 						= ( portBASE_TYPE ) pdFALSE;
PRIVILEGED_DATA static volatile portBASE_TYPE xNumOfOverflows 					= ( portBASE_TYPE ) 0;
PRIVILEGED_DATA static unsigned portBASE_TYPE uxTaskNumber 						= ( unsigned portBASE_TYPE ) 0;

#if ( configGENERATE_RUN_TIME_STATS == 1 )

	PRIVILEGED_DATA static char pcStatsString[ 50 ] ;
	PRIVILEGED_DATA static unsigned long ulTaskSwitchedInTime = 0UL;	/*< Holds the value of a timer/counter the last time a task was switched in. */
	static void prvGenerateRunTimeStatsForTasksInList( const signed char *pcWriteBuffer, xList *pxList, unsigned long ulTotalRunTime ) PRIVILEGED_FUNCTION;

#endif

/* Debugging and trace facilities private variables and macros. ------------*/

/*
 * The value used to fill the stack of a task when the task is created.  This
 * is used purely for checking the high water mark for tasks.
 */
#define tskSTACK_FILL_BYTE	( 0xa5 )

/*
 * Macros used by vListTask to indicate which state a task is in.
 */
#define tskBLOCKED_CHAR		( ( signed char ) 'B' )
#define tskREADY_CHAR		( ( signed char ) 'R' )
#define tskDELETED_CHAR		( ( signed char ) 'D' )
#define tskSUSPENDED_CHAR	( ( signed char ) 'S' )

/*
 * Macros and private variables used by the trace facility.
 */
#if ( configUSE_TRACE_FACILITY == 1 )

	#define tskSIZE_OF_EACH_TRACE_LINE			( ( unsigned long ) ( sizeof( unsigned long ) + sizeof( unsigned long ) ) )
	PRIVILEGED_DATA static volatile signed char * volatile pcTraceBuffer;
	PRIVILEGED_DATA static signed char *pcTraceBufferStart;
	PRIVILEGED_DATA static signed char *pcTraceBufferEnd;
	PRIVILEGED_DATA static signed portBASE_TYPE xTracing = pdFALSE;
	static unsigned portBASE_TYPE uxPreviousTask = 255;
	PRIVILEGED_DATA static char pcStatusString[ 50 ];

#endif

/*-----------------------------------------------------------*/

/*
 * Macro that writes a trace of scheduler activity to a buffer.  This trace
 * shows which task is running when and is very useful as a debugging tool.
 * As this macro is called each context switch it is a good idea to undefine
 * it if not using the facility.
 */
#if ( configUSE_TRACE_FACILITY == 1 )

	#define vWriteTraceToBuffer()																	\
	{																								\
		if( xTracing )																				\
		{																							\
			if( uxPreviousTask != pxCurrentTCB->uxTCBNumber )										\
			{																						\
				if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd )				\
				{																					\
					uxPreviousTask = pxCurrentTCB->uxTCBNumber;										\
					*( unsigned long * ) pcTraceBuffer = ( unsigned long ) xTickCount;		\
					pcTraceBuffer += sizeof( unsigned long );									\
					*( unsigned long * ) pcTraceBuffer = ( unsigned long ) uxPreviousTask;	\
					pcTraceBuffer += sizeof( unsigned long );									\
				}																					\
				else																				\
				{																					\
					xTracing = pdFALSE;																\
				}																					\
			}																						\
		}																							\
	}

#else

	#define vWriteTraceToBuffer()

#endif
/*-----------------------------------------------------------*/

/*
 * Place the task represented by pxTCB into the appropriate ready queue for
 * the task.  It is inserted at the end of the list.  One quirk of this is
 * that if the task being inserted is at the same priority as the currently
 * executing task, then it will only be rescheduled after the currently
 * executing task has been rescheduled.
 */
#define prvAddTaskToReadyQueue( pxTCB )																			\
{																												\
	if( pxTCB->uxPriority > uxTopReadyPriority )																\
	{																											\
		uxTopReadyPriority = pxTCB->uxPriority;																	\
	}																											\
	vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) );	\
}
/*-----------------------------------------------------------*/

/*
 * Macro that looks at the list of tasks that are currently delayed to see if
 * any require waking.
 *
 * Tasks are stored in the queue in the order of their wake time - meaning
 * once one tasks has been found whose timer has not expired we need not look
 * any further down the list.
 */
#define prvCheckDelayedTasks()																						\
{																													\
register tskTCB *pxTCB;																								\
																													\
	while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL )						\
	{																												\
		if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) )									\
		{																											\
			break;																									\
		}																											\
		vListRemove( &( pxTCB->xGenericListItem ) );																\
		/* Is the task waiting on an event also? */																	\
		if( pxTCB->xEventListItem.pvContainer )																		\
		{																											\
			vListRemove( &( pxTCB->xEventListItem ) );																\
		}																											\
		prvAddTaskToReadyQueue( pxTCB );																			\
	}																												\
}
/*-----------------------------------------------------------*/

/*
 * Several functions take an xTaskHandle parameter that can optionally be NULL,
 * where NULL is used to indicate that the handle of the currently executing
 * task should be used in place of the parameter.  This macro simply checks to
 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
 */
#define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )


/* File private functions. --------------------------------*/

/*
 * Utility to ready a TCB for a given task.  Mainly just copies the parameters
 * into the TCB structure.
 */
static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed char * const pcName, unsigned portBASE_TYPE uxPriority, const xMemoryRegion * const xRegions, unsigned short usStackDepth ) PRIVILEGED_FUNCTION;

/*
 * Utility to ready all the lists used by the scheduler.  This is called
 * automatically upon the creation of the first task.
 */
static void prvInitialiseTaskLists( void ) PRIVILEGED_FUNCTION;

/*
 * The idle task, which as all tasks is implemented as a never ending loop.
 * The idle task is automatically created and added to the ready lists upon
 * creation of the first user task.
 *
 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
 * language extensions.  The equivalent prototype for this function is:
 *
 * void prvIdleTask( void *pvParameters );
 *
 */
static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );

/*
 * Utility to free all memory allocated by the scheduler to hold a TCB,
 * including the stack pointed to by the TCB.
 *
 * This does not free memory allocated by the task itself (i.e. memory
 * allocated by calls to pvPortMalloc from within the tasks application code).
 */
#if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )

	static void prvDeleteTCB( tskTCB *pxTCB ) PRIVILEGED_FUNCTION;

#endif

/*
 * Used only by the idle task.  This checks to see if anything has been placed
 * in the list of tasks waiting to be deleted.  If so the task is cleaned up
 * and its TCB deleted.
 */
static void prvCheckTasksWaitingTermination( void ) PRIVILEGED_FUNCTION;

/*
 * Allocates memory from the heap for a TCB and associated stack.  Checks the
 * allocation was successful.
 */
static tskTCB *prvAllocateTCBAndStack( unsigned short usStackDepth, portSTACK_TYPE *puxStackBuffer ) PRIVILEGED_FUNCTION;

/*
 * Called from vTaskList.  vListTasks details all the tasks currently under
 * control of the scheduler.  The tasks may be in one of a number of lists.
 * prvListTaskWithinSingleList accepts a list and details the tasks from
 * within just that list.
 *
 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
 * NORMAL APPLICATION CODE.
 */
#if ( configUSE_TRACE_FACILITY == 1 )

	static void prvListTaskWithinSingleList( const signed char *pcWriteBuffer, xList *pxList, signed char cStatus ) PRIVILEGED_FUNCTION;

#endif

/*
 * When a task is created, the stack of the task is filled with a known value.
 * This function determines the 'high water mark' of the task stack by
 * determining how much of the stack remains at the original preset value.
 */
#if ( ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) )

	static unsigned short usTaskCheckFreeStackSpace( const unsigned char * pucStackByte ) PRIVILEGED_FUNCTION;

#endif


/*lint +e956 */



/*-----------------------------------------------------------
 * TASK CREATION API documented in task.h
 *----------------------------------------------------------*/

signed portBASE_TYPE xTaskGenericCreate( pdTASK_CODE pxTaskCode, const signed char * const pcName, unsigned short usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask, portSTACK_TYPE *puxStackBuffer, const xMemoryRegion * const xRegions )
{
signed portBASE_TYPE xReturn;
tskTCB * pxNewTCB;

	/* Allocate the memory required by the TCB and stack for the new task,
	checking that the allocation was successful. */
	pxNewTCB = prvAllocateTCBAndStack( usStackDepth, puxStackBuffer );

	if( pxNewTCB != NULL )
	{
		portSTACK_TYPE *pxTopOfStack;

		#if( portUSING_MPU_WRAPPERS == 1 )
			/* Should the task be created in privileged mode? */
			portBASE_TYPE xRunPrivileged;
			if( ( uxPriority & portPRIVILEGE_BIT ) != 0x00 )
			{
				xRunPrivileged = pdTRUE;