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/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
/*
Changes from V3.2.1
+ CallReturn Depth increased from 8 to 10 levels to accommodate 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 TCB_t;
extern volatile TCB_t * 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 )
uint16_t usCalcMinStackSize = 0;
/*-----------------------------------------------------------*/
/*
* We initialise ucCriticalNesting to the middle value an
* uint8_t can contain. This way portENTER_CRITICAL()
* and portEXIT_CRITICAL() can be called without interrupts
* being enabled before the scheduler starts.
*/
register uint8_t ucCriticalNesting = 0x7F;
/*-----------------------------------------------------------*/
/*
* Initialise the stack of a new task.
* See portSAVE_CONTEXT macro for description.
*/
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
uint8_t 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-- = ( StackType_t ) ( (( uint16_t ) pvParameters >> 8) & 0x00ff );
*pxTopOfStack-- = ( StackType_t ) ( ( uint16_t ) pvParameters & 0x00ff );
/*
* Next are all the registers that form part of the task context.
*/
*pxTopOfStack-- = ( StackType_t ) 0x11; /* STATUS. */
*pxTopOfStack-- = ( StackType_t ) 0x22; /* WREG. */
*pxTopOfStack-- = ( StackType_t ) 0x33; /* BSR. */
*pxTopOfStack-- = ( StackType_t ) 0x44; /* PRODH. */
*pxTopOfStack-- = ( StackType_t ) 0x55; /* PRODL. */
*pxTopOfStack-- = ( StackType_t ) 0x66; /* FSR0H. */
*pxTopOfStack-- = ( StackType_t ) 0x77; /* FSR0L. */
*pxTopOfStack-- = ( StackType_t ) 0x88; /* FSR1H. */
*pxTopOfStack-- = ( StackType_t ) 0x99; /* FSR1L. */
*pxTopOfStack-- = ( StackType_t ) 0xAA; /* TABLAT. */
#if _ROMSIZE > 0x8000
*pxTopOfStack-- = ( StackType_t ) 0x00; /* TBLPTRU. */
#endif
*pxTopOfStack-- = ( StackType_t ) 0xCC; /* TBLPTRH. */
*pxTopOfStack-- = ( StackType_t ) 0xDD; /* TBLPTRL. */
#if _ROMSIZE > 0x8000
*pxTopOfStack-- = ( StackType_t ) 0xEE; /* PCLATU. */
#endif
*pxTopOfStack-- = ( StackType_t ) 0xFF; /* PCLATH. */
/*
* Next the compiler's scratchspace.
*/
while(ucScratch-- > 0)
{
*pxTopOfStack-- = ( StackType_t ) 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-- = ( StackType_t ) 0;
#endif
*pxTopOfStack-- = ( StackType_t ) ( ( ( uint16_t ) pxCode >> 8 ) & 0x00ff );
*pxTopOfStack-- = ( StackType_t ) ( ( uint16_t ) pxCode & 0x00ff );
/*
* Store the number of return addresses on the hardware stack.
* So far only the address of the task entry point.
*/
*pxTopOfStack-- = ( StackType_t ) 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-- = ( StackType_t ) portNO_CRITICAL_SECTION_NESTING;
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
uint16_t 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);
}
/*-----------------------------------------------------------*/
BaseType_t 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();
}
/*-----------------------------------------------------------*/
#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
void *pvPortMalloc( uint16_t usWantedSize )
{
void *pvReturn;
vTaskSuspendAll();
{
pvReturn = malloc( ( malloc_t ) usWantedSize );
}
xTaskResumeAll();
return pvReturn;
}
#endif /* configSUPPORT_STATIC_ALLOCATION */
/*-----------------------------------------------------------*/
#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
void vPortFree( void *pv )
{
if( pv )
{
vTaskSuspendAll();
{
free( pv );
}
xTaskResumeAll();
}
}
#endif /* configSUPPORT_DYNAMIC_ALLOCATION */