Subversion Repositories openrisc_2011-10-31

/*

    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.

    ***************************************************************************

    *                                                                         *

    * If you are:                                                             *

    *                                                                         *

    *    + New to FreeRTOS,                                                   *

    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *

    *    + Looking for basic training,                                        *

    *    + Wanting to improve your FreeRTOS skills and productivity           *

    *                                                                         *

    * then take a look at the FreeRTOS books - available as PDF or paperback  *

    *                                                                         *

    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *

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

    *                                                                         *

    * A pdf reference manual is also available.  Both are usually delivered   *

    * to your inbox within 20 minutes to two hours when purchased between 8am *

    * and 8pm GMT (although please allow up to 24 hours in case of            *

    * exceptional circumstances).  Thank you for your support!                *

    *                                                                         *

    ***************************************************************************

    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

    a combined work that includes FreeRTOS without being obliged to provide the

    source code for proprietary components outside of the FreeRTOS kernel.

    FreeRTOS 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 and the FreeRTOS license exception along with FreeRTOS; if not it

    can be viewed here: http://www.freertos.org/a00114.html and also obtained

    by writing to Richard Barry, contact details for whom are available on the

    FreeRTOS WEB site.

    1 tab == 4 spaces!

    http://www.FreeRTOS.org - Documentation, latest information, license and

    contact details.

    http://www.SafeRTOS.com - A version that is certified for use in safety

    critical systems.

    http://www.OpenRTOS.com - Commercial support, development, porting,

    licensing and training services.

*/

/*

Changes from V3.2.1

        + CallReturn Depth increased from 8 to 10 levels to accomodate wizC/fedC V12.

Changes from V3.2.0

        + TBLPTRU is now initialised to zero during the initial stack creation of a new task. This solves

        an error on devices with more than 64kB ROM.

Changes from V3.0.0

        + ucCriticalNesting is now initialised to 0x7F to prevent interrupts from being

          handled before the scheduler is started.

Changes from V3.0.1

*/

/* Scheduler include files. */

#include <FreeRTOS.h>

#include <task.h>

#include <malloc.h>

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

 * Implementation of functions defined in portable.h for the WizC PIC18 port.

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

/*

 * We require the address of the pxCurrentTCB variable, but don't want to

 * know any details of its type.

 */

typedef void tskTCB;

extern volatile tskTCB * volatile pxCurrentTCB;

/*

 * Define minimal-stack constants

 * -----

 * FSR's:

 *              STATUS, WREG, BSR, PRODH, PRODL, FSR0H, FSR0L,

 *              FSR1H, FSR1L,TABLAT, (TBLPTRU), TBLPTRH, TBLPTRL,

 *              (PCLATU), PCLATH

 *              sfr's within parenthesis only on devices > 64kB

 * -----

 * Call/Return stack:

 *               2 bytes per entry on devices <= 64kB

 *               3 bytes per entry on devices >  64kB

 * -----

 * Other bytes:

 *               2 bytes: FunctionParameter for initial taskcode

 *               1 byte : Number of entries on call/return stack

 *               1 byte : ucCriticalNesting

 *              16 bytes: Free space on stack

 */

#if _ROMSIZE > 0x8000

        #define portSTACK_FSR_BYTES                             ( 15 )

        #define portSTACK_CALLRETURN_ENTRY_SIZE (  3 )

#else

        #define portSTACK_FSR_BYTES                             ( 13 )

        #define portSTACK_CALLRETURN_ENTRY_SIZE (  2 )

#endif

#define portSTACK_MINIMAL_CALLRETURN_DEPTH      ( 10 )

#define portSTACK_OTHER_BYTES                           ( 20 )

unsigned short usCalcMinStackSize               = 0;

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

/*

 * We initialise ucCriticalNesting to the middle value an

 * unsigned char can contain. This way portENTER_CRITICAL()

 * and portEXIT_CRITICAL() can be called without interrupts

 * being enabled before the scheduler starts.

 */

register unsigned char ucCriticalNesting = 0x7F;

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

/*

 * Initialise the stack of a new task.

 * See portSAVE_CONTEXT macro for description.

 */

portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )

{

unsigned char ucScratch;

        /*

         * Get the size of the RAMarea in page 0 used by the compiler

         * We do this here already to avoid W-register conflicts.

         */

        _Pragma("asm")

                movlw   OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE

                movwf   PRODL,ACCESS            ; PRODL is used as temp register

        _Pragma("asmend")

        ucScratch = PRODL;

        /*

         * Place a few bytes of known values on the bottom of the stack.

         * This is just useful for debugging.

         */

//      *pxTopOfStack-- = 0x11;

//      *pxTopOfStack-- = 0x22;

//      *pxTopOfStack-- = 0x33;

        /*

         * Simulate how the stack would look after a call to vPortYield()

         * generated by the compiler.

         */

        /*

         * First store the function parameters.  This is where the task expects

         * to find them when it starts running.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) ( (( unsigned short ) pvParameters >> 8) & 0x00ff );

        *pxTopOfStack-- = ( portSTACK_TYPE ) (  ( unsigned short ) pvParameters       & 0x00ff );

        /*

         * Next are all the registers that form part of the task context.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x11; /* STATUS. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x22; /* WREG. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x33; /* BSR. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x44; /* PRODH. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x55; /* PRODL. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x66; /* FSR0H. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x77; /* FSR0L. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x88; /* FSR1H. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x99; /* FSR1L. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xAA; /* TABLAT. */

#if _ROMSIZE > 0x8000

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x00; /* TBLPTRU. */

#endif

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xCC; /* TBLPTRH. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xDD; /* TBLPTRL. */

#if _ROMSIZE > 0x8000

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xEE; /* PCLATU. */

#endif

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xFF; /* PCLATH. */

        /*

         * Next the compiler's scratchspace.

         */

        while(ucScratch-- > 0)

        {

                *pxTopOfStack-- = ( portSTACK_TYPE ) 0;

        }

        /*

         * The only function return address so far is the address of the task entry.

         * The order is TOSU/TOSH/TOSL. For devices > 64kB, TOSU is put on the

         * stack, too. TOSU is always written as zero here because wizC does not allow

         * functionpointers to point above 64kB in ROM.

         */

#if _ROMSIZE > 0x8000

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0;

#endif

        *pxTopOfStack-- = ( portSTACK_TYPE ) ( ( ( unsigned short ) pxCode >> 8 ) & 0x00ff );

        *pxTopOfStack-- = ( portSTACK_TYPE ) ( (   unsigned short ) pxCode        & 0x00ff );

        /*

         * Store the number of return addresses on the hardware stack.

         * So far only the address of the task entry point.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 1;

        /*

         * The code generated by wizC does not maintain separate

         * stack and frame pointers. Therefore the portENTER_CRITICAL macro cannot

         * use the stack as per other ports.  Instead a variable is used to keep

         * track of the critical section nesting.  This variable has to be stored

         * as part of the task context and is initially set to zero.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) portNO_CRITICAL_SECTION_NESTING;

        return pxTopOfStack;

}

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

unsigned short usPortCALCULATE_MINIMAL_STACK_SIZE( void )

{

        /*

         * Fetch the size of compiler's scratchspace.

         */

        _Pragma("asm")

                movlw   OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE

                movlb   usCalcMinStackSize>>8

                movwf   usCalcMinStackSize,BANKED

        _Pragma("asmend")

        /*

         * Add minimum needed stackspace

         */

        usCalcMinStackSize      +=      ( portSTACK_FSR_BYTES )

                +       ( portSTACK_MINIMAL_CALLRETURN_DEPTH * portSTACK_CALLRETURN_ENTRY_SIZE )

                +       ( portSTACK_OTHER_BYTES );

        return(usCalcMinStackSize);

}

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

portBASE_TYPE xPortStartScheduler( void )

{

        extern void portSetupTick( void );

        /*

         * Setup a timer for the tick ISR for the preemptive scheduler.

         */

        portSetupTick();

        /*

         * Restore the context of the first task to run.

         */

        portRESTORE_CONTEXT();

        /*

         * This point should never be reached during execution.

         */

        return pdTRUE;

}

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

void vPortEndScheduler( void )

{

        /*

         * It is unlikely that the scheduler for the PIC port will get stopped

         * once running. When called a reset is done which is probably the

         * most valid action.

         */

        _Pragma(asmline reset);

}

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

/*

 * Manual context switch.  This is similar to the tick context switch,

 * but does not increment the tick count.  It must be identical to the

 * tick context switch in how it stores the stack of a task.

 */

void vPortYield( void )

{

        /*

         * Save the context of the current task.

         */

        portSAVE_CONTEXT( portINTERRUPTS_UNCHANGED );

        /*

         * Switch to the highest priority task that is ready to run.

         */

        vTaskSwitchContext();

        /*

         * Start executing the task we have just switched to.

         */

        portRESTORE_CONTEXT();

}

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

void *pvPortMalloc( unsigned short usWantedSize )

{

void *pvReturn;

        vTaskSuspendAll();

        {

                pvReturn = malloc( ( malloc_t ) usWantedSize );

        }

        xTaskResumeAll();

        return pvReturn;

}

void vPortFree( void *pv )

{

        if( pv )

        {

                vTaskSuspendAll();

                {

                        free( pv );

                }

                xTaskResumeAll();

        }

}