You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
314 lines
12 KiB
C
314 lines
12 KiB
C
/*
|
|
FreeRTOS V6.0.5 - Copyright (C) 2010 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 eBook *
|
|
* *
|
|
* "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.
|
|
*/
|
|
|
|
|
|
/* Standard includes. */
|
|
#include <stdlib.h>
|
|
|
|
/* Scheduler includes. */
|
|
#include "FreeRTOS.h"
|
|
#include "task.h"
|
|
|
|
/* Constants required to setup the initial task context. */
|
|
#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 )
|
|
#define portNO_CRITICAL_SECTION_NESTING ( ( portSTACK_TYPE ) 0 )
|
|
|
|
/* Constants required to setup the tick ISR. */
|
|
#define portENABLE_TIMER ( ( unsigned portCHAR ) 0x01 )
|
|
#define portPRESCALE_VALUE 0x00
|
|
#define portINTERRUPT_ON_MATCH ( ( unsigned portLONG ) 0x01 )
|
|
#define portRESET_COUNT_ON_MATCH ( ( unsigned portLONG ) 0x02 )
|
|
|
|
/* Constants required to setup the VIC for the tick ISR. */
|
|
#define portTIMER_VIC_CHANNEL ( ( unsigned portLONG ) 0x0004 )
|
|
#define portTIMER_VIC_CHANNEL_BIT ( ( unsigned portLONG ) 0x0010 )
|
|
#define portTIMER_VIC_ENABLE ( ( unsigned portLONG ) 0x0020 )
|
|
|
|
/* Constants required to handle interrupts. */
|
|
#define portTIMER_MATCH_ISR_BIT ( ( unsigned portCHAR ) 0x01 )
|
|
#define portCLEAR_VIC_INTERRUPT ( ( unsigned portLONG ) 0 )
|
|
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/* The code generated by the Keil compiler does not maintain separate
|
|
stack and frame pointers. The portENTER_CRITICAL macro cannot therefore
|
|
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 must be initialised to a non zero value. */
|
|
|
|
#define portNO_CRITICAL_NESTING ( ( unsigned portLONG ) 0 )
|
|
volatile unsigned portLONG ulCriticalNesting = 9999UL;
|
|
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/* Setup the timer to generate the tick interrupts. */
|
|
static void prvSetupTimerInterrupt( void );
|
|
|
|
/*
|
|
* The scheduler can only be started from ARM mode, so
|
|
* vPortStartFirstSTask() is defined in portISR.c.
|
|
*/
|
|
extern __asm void vPortStartFirstTask( void );
|
|
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/*
|
|
* See header file for description.
|
|
*/
|
|
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
|
|
{
|
|
portSTACK_TYPE *pxOriginalTOS;
|
|
|
|
/* Setup the initial stack of the task. The stack is set exactly as
|
|
expected by the portRESTORE_CONTEXT() macro.
|
|
|
|
Remember where the top of the (simulated) stack is before we place
|
|
anything on it. */
|
|
pxOriginalTOS = pxTopOfStack;
|
|
|
|
/* 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--;
|
|
*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
|
|
pxTopOfStack--;
|
|
|
|
/* The last thing onto the stack is the status register, which 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--;
|
|
|
|
/* The code generated by the Keil compiler does not maintain separate
|
|
stack and frame pointers. The portENTER_CRITICAL macro cannot therefore
|
|
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 = portNO_CRITICAL_SECTION_NESTING;
|
|
|
|
return pxTopOfStack;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
portBASE_TYPE xPortStartScheduler( void )
|
|
{
|
|
/* Start the timer that generates the tick ISR. */
|
|
prvSetupTimerInterrupt();
|
|
|
|
/* Start the first task. This is done from portISR.c as ARM mode must be
|
|
used. */
|
|
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. If this is required - stop the tick ISR then
|
|
return back to main. */
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
#if configUSE_PREEMPTION == 0
|
|
|
|
/*
|
|
* The cooperative scheduler requires a normal IRQ service routine to
|
|
* simply increment the system tick.
|
|
*/
|
|
void vNonPreemptiveTick( void ) __irq;
|
|
void vNonPreemptiveTick( void ) __irq
|
|
{
|
|
/* Increment the tick count - this may make a delaying task ready
|
|
to run - but a context switch is not performed. */
|
|
vTaskIncrementTick();
|
|
|
|
T0IR = portTIMER_MATCH_ISR_BIT; /* Clear the timer event */
|
|
VICVectAddr = portCLEAR_VIC_INTERRUPT; /* Acknowledge the Interrupt */
|
|
}
|
|
|
|
#else
|
|
|
|
/*
|
|
**************************************************************************
|
|
* The preemptive scheduler ISR is written in assembler and can be found
|
|
* in the portASM.s file. This will only get used if portUSE_PREEMPTION
|
|
* is set to 1 in portmacro.h
|
|
**************************************************************************
|
|
*/
|
|
|
|
void vPreemptiveTick( void );
|
|
|
|
#endif
|
|
/*-----------------------------------------------------------*/
|
|
|
|
static void prvSetupTimerInterrupt( void )
|
|
{
|
|
unsigned portLONG ulCompareMatch;
|
|
|
|
/* A 1ms tick does not require the use of the timer prescale. This is
|
|
defaulted to zero but can be used if necessary. */
|
|
T0PR = portPRESCALE_VALUE;
|
|
|
|
/* Calculate the match value required for our wanted tick rate. */
|
|
ulCompareMatch = configCPU_CLOCK_HZ / configTICK_RATE_HZ;
|
|
|
|
/* Protect against divide by zero. Using an if() statement still results
|
|
in a warning - hence the #if. */
|
|
#if portPRESCALE_VALUE != 0
|
|
{
|
|
ulCompareMatch /= ( portPRESCALE_VALUE + 1 );
|
|
}
|
|
#endif
|
|
|
|
T0MR0 = ulCompareMatch;
|
|
|
|
/* Generate tick with timer 0 compare match. */
|
|
T0MCR = portRESET_COUNT_ON_MATCH | portINTERRUPT_ON_MATCH;
|
|
|
|
/* Setup the VIC for the timer. */
|
|
VICIntSelect &= ~( portTIMER_VIC_CHANNEL_BIT );
|
|
VICIntEnable |= portTIMER_VIC_CHANNEL_BIT;
|
|
|
|
/* The ISR installed depends on whether the preemptive or cooperative
|
|
scheduler is being used. */
|
|
#if configUSE_PREEMPTION == 1
|
|
{
|
|
VICVectAddr0 = ( unsigned portLONG ) vPreemptiveTick;
|
|
}
|
|
#else
|
|
{
|
|
VICVectAddr0 = ( unsigned portLONG ) vNonPreemptiveTick;
|
|
}
|
|
#endif
|
|
|
|
VICVectCntl0 = portTIMER_VIC_CHANNEL | portTIMER_VIC_ENABLE;
|
|
|
|
/* Start the timer - interrupts are disabled when this function is called
|
|
so it is okay to do this here. */
|
|
T0TCR = portENABLE_TIMER;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
void vPortEnterCritical( void )
|
|
{
|
|
/* Disable interrupts as per portDISABLE_INTERRUPTS(); */
|
|
__disable_irq();
|
|
|
|
/* 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++;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
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 interrupts as per portEXIT_CRITICAL(). */
|
|
__enable_irq();
|
|
}
|
|
}
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
|