/* | |
* 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 | |
* | |
*/ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the MSP430X port. | |
*----------------------------------------------------------*/ | |
/* Constants required for hardware setup. The tick ISR runs off the ACLK, | |
not the MCLK. */ | |
#define portACLK_FREQUENCY_HZ ( ( TickType_t ) 32768 ) | |
#define portINITIAL_CRITICAL_NESTING ( ( uint16_t ) 10 ) | |
#define portFLAGS_INT_ENABLED ( ( StackType_t ) 0x08 ) | |
/* 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; | |
/* Each task maintains a count of the critical section nesting depth. Each | |
time a critical section is entered the count is incremented. Each time a | |
critical section is exited the count is decremented - with interrupts only | |
being re-enabled if the count is zero. | |
usCriticalNesting will get set to zero when the scheduler starts, but must | |
not be initialised to zero as this will cause problems during the startup | |
sequence. */ | |
volatile uint16_t usCriticalNesting = portINITIAL_CRITICAL_NESTING; | |
/*-----------------------------------------------------------*/ | |
/* | |
* Sets up the periodic ISR used for the RTOS tick. This uses timer 0, but | |
* could have alternatively used the watchdog timer or timer 1. | |
*/ | |
void vPortSetupTimerInterrupt( void ); | |
/*-----------------------------------------------------------*/ | |
/* | |
* Initialise the stack of a task to look exactly as if a call to | |
* portSAVE_CONTEXT had been called. | |
* | |
* See the header file portable.h. | |
*/ | |
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters ) | |
{ | |
uint16_t *pusTopOfStack; | |
uint32_t *pulTopOfStack; | |
/* | |
Place a few bytes of known values on the bottom of the stack. | |
This is just useful for debugging and can be included if required. | |
*pxTopOfStack = ( StackType_t ) 0x1111; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x2222; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x3333; | |
*/ | |
/* StackType_t is either 16 bits or 32 bits depending on the data model. | |
Some stacked items do not change size depending on the data model so have | |
to be explicitly cast to the correct size so this function will work | |
whichever data model is being used. */ | |
if( sizeof( StackType_t ) == sizeof( uint16_t ) ) | |
{ | |
/* Make room for a 20 bit value stored as a 32 bit value. */ | |
pusTopOfStack = ( uint16_t * ) pxTopOfStack; | |
pusTopOfStack--; | |
pulTopOfStack = ( uint32_t * ) pusTopOfStack; | |
} | |
else | |
{ | |
pulTopOfStack = ( uint32_t * ) pxTopOfStack; | |
} | |
*pulTopOfStack = ( uint32_t ) pxCode; | |
pusTopOfStack = ( uint16_t * ) pulTopOfStack; | |
pusTopOfStack--; | |
*pusTopOfStack = portFLAGS_INT_ENABLED; | |
pusTopOfStack -= ( sizeof( StackType_t ) / 2 ); | |
/* From here on the size of stacked items depends on the memory model. */ | |
pxTopOfStack = ( StackType_t * ) pusTopOfStack; | |
/* Next the general purpose registers. */ | |
#ifdef PRELOAD_REGISTER_VALUES | |
*pxTopOfStack = ( StackType_t ) 0xffff; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0xeeee; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0xdddd; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) pvParameters; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0xbbbb; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0xaaaa; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x9999; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x8888; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x5555; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x6666; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x5555; | |
pxTopOfStack--; | |
*pxTopOfStack = ( StackType_t ) 0x4444; | |
pxTopOfStack--; | |
#else | |
pxTopOfStack -= 3; | |
*pxTopOfStack = ( StackType_t ) pvParameters; | |
pxTopOfStack -= 9; | |
#endif | |
/* 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 a pointer to the top of the stack we have generated so this can | |
be stored in the task control block for the task. */ | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* It is unlikely that the MSP430 port will get stopped. If required simply | |
disable the tick interrupt here. */ | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Hardware initialisation to generate the RTOS tick. | |
*/ | |
void vPortSetupTimerInterrupt( void ) | |
{ | |
vApplicationSetupTimerInterrupt(); | |
} | |
/*-----------------------------------------------------------*/ | |
#pragma vector=configTICK_VECTOR | |
__interrupt __raw void vTickISREntry( void ) | |
{ | |
extern void vPortTickISR( void ); | |
__bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF ); | |
vPortTickISR(); | |
} | |