/* | |
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 * | |
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* * | |
* 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 * | |
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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 | |
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 | |
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licensing and training services. | |
*/ | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the ST STR71x ARM7 | |
* port. | |
*----------------------------------------------------------*/ | |
/* Library includes. */ | |
#include "wdg.h" | |
#include "eic.h" | |
/* Standard includes. */ | |
#include <stdlib.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/* Constants required to setup the initial stack. */ | |
#define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */ | |
#define portTHUMB_MODE_BIT ( ( portSTACK_TYPE ) 0x20 ) | |
#define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 ) | |
/* Constants required to handle critical sections. */ | |
#define portNO_CRITICAL_NESTING ( ( unsigned long ) 0 ) | |
#define portMICROS_PER_SECOND 1000000 | |
/*-----------------------------------------------------------*/ | |
/* Setup the watchdog to generate the tick interrupts. */ | |
static void prvSetupTimerInterrupt( void ); | |
/* ulCriticalNesting will get set to zero when the first task starts. It | |
cannot be initialised to 0 as this will cause interrupts to be enabled | |
during the kernel initialisation process. */ | |
unsigned long ulCriticalNesting = ( unsigned long ) 9999; | |
/* Tick interrupt routines for cooperative and preemptive operation | |
respectively. The preemptive version is not defined as __irq as it is called | |
from an asm wrapper function. */ | |
__arm __irq void vPortNonPreemptiveTick( void ); | |
void vPortPreemptiveTick( void ); | |
/*-----------------------------------------------------------*/ | |
/* | |
* Initialise the stack of a task to look exactly as if a call to | |
* portSAVE_CONTEXT had been called. | |
* | |
* See header file for description. | |
*/ | |
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
{ | |
portSTACK_TYPE *pxOriginalTOS; | |
pxOriginalTOS = pxTopOfStack; | |
/* Setup the initial stack of the task. The stack is set exactly as | |
expected by the portRESTORE_CONTEXT() macro. */ | |
/* First on the stack is the return address - which in this case is the | |
start of the task. The offset is added to make the return address appear | |
as it would within an IRQ ISR. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE; | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */ | |
pxTopOfStack--; | |
/* When the task starts is will expect to find the function parameter in | |
R0. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */ | |
pxTopOfStack--; | |
/* The status register is set for system mode, with interrupts enabled. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR; | |
if( ( ( unsigned long ) pxCode & 0x01UL ) != 0x00UL ) | |
{ | |
/* We want the task to start in thumb mode. */ | |
*pxTopOfStack |= portTHUMB_MODE_BIT; | |
} | |
pxTopOfStack--; | |
/* Interrupt flags cannot always be stored on the stack and will | |
instead be stored in a variable, which is then saved as part of the | |
tasks context. */ | |
*pxTopOfStack = portNO_CRITICAL_NESTING; | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xPortStartScheduler( void ) | |
{ | |
extern void vPortStartFirstTask( void ); | |
/* Start the timer that generates the tick ISR. Interrupts are disabled | |
here already. */ | |
prvSetupTimerInterrupt(); | |
/* Start the first task. */ | |
vPortStartFirstTask(); | |
/* Should not get here! */ | |
return 0; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* It is unlikely that the ARM port will require this function as there | |
is nothing to return to. */ | |
} | |
/*-----------------------------------------------------------*/ | |
/* The cooperative scheduler requires a normal IRQ service routine to | |
simply increment the system tick. */ | |
__arm __irq void vPortNonPreemptiveTick( void ) | |
{ | |
/* Increment the tick count - which may wake some tasks but as the | |
preemptive scheduler is not being used any woken task is not given | |
processor time no matter what its priority. */ | |
vTaskIncrementTick(); | |
/* Clear the interrupt in the watchdog and EIC. */ | |
WDG->SR = 0x0000; | |
portCLEAR_EIC(); | |
} | |
/*-----------------------------------------------------------*/ | |
/* This function is called from an asm wrapper, so does not require the __irq | |
keyword. */ | |
void vPortPreemptiveTick( void ) | |
{ | |
/* Increment the tick counter. */ | |
vTaskIncrementTick(); | |
/* The new tick value might unblock a task. Ensure the highest task that | |
is ready to execute is the task that will execute when the tick ISR | |
exits. */ | |
vTaskSwitchContext(); | |
/* Clear the interrupt in the watchdog and EIC. */ | |
WDG->SR = 0x0000; | |
portCLEAR_EIC(); | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvSetupTimerInterrupt( void ) | |
{ | |
/* Set the watchdog up to generate a periodic tick. */ | |
WDG_ECITConfig( DISABLE ); | |
WDG_CntOnOffConfig( DISABLE ); | |
WDG_PeriodValueConfig( portMICROS_PER_SECOND / configTICK_RATE_HZ ); | |
/* Setup the tick interrupt in the EIC. */ | |
EIC_IRQChannelPriorityConfig( WDG_IRQChannel, 1 ); | |
EIC_IRQChannelConfig( WDG_IRQChannel, ENABLE ); | |
EIC_IRQConfig( ENABLE ); | |
WDG_ECITConfig( ENABLE ); | |
/* Start the timer - interrupts are actually disabled at this point so | |
it is safe to do this here. */ | |
WDG_CntOnOffConfig( ENABLE ); | |
} | |
/*-----------------------------------------------------------*/ | |
__arm __interwork void vPortEnterCritical( void ) | |
{ | |
/* Disable interrupts first! */ | |
__disable_interrupt(); | |
/* Now interrupts are disabled ulCriticalNesting can be accessed | |
directly. Increment ulCriticalNesting to keep a count of how many times | |
portENTER_CRITICAL() has been called. */ | |
ulCriticalNesting++; | |
} | |
/*-----------------------------------------------------------*/ | |
__arm __interwork void vPortExitCritical( void ) | |
{ | |
if( ulCriticalNesting > portNO_CRITICAL_NESTING ) | |
{ | |
/* Decrement the nesting count as we are leaving a critical section. */ | |
ulCriticalNesting--; | |
/* If the nesting level has reached zero then interrupts should be | |
re-enabled. */ | |
if( ulCriticalNesting == portNO_CRITICAL_NESTING ) | |
{ | |
__enable_interrupt(); | |
} | |
} | |
} | |
/*-----------------------------------------------------------*/ | |