/*
FreeRTOS V4.1.1 - Copyright (C) 2003-2006 Richard Barry.
MCF5235 Port - Copyright (C) 2006 Christian Walter.
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** as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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
along with FreeRTOS; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
***************************************************************************
* *
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
* *
* This is a concise, step by step, 'hands on' guide that describes both *
* general multitasking concepts and FreeRTOS specifics. It presents and *
* explains numerous examples that are written using the FreeRTOS API. *
* Full source code for all the examples is provided in an accompanying *
* .zip file. *
* *
***************************************************************************
***************************************************************************
Please ensure to read the configuration and relevant port sections of the
online documentation.
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.
*/
#include <stdlib.h>
#include "FreeRTOS.h"
#include "FreeRTOSConfig.h"
#include "task.h"
/* ------------------------ Types ----------------------------------------- */
typedef volatile uint32_t vuint32;
typedef volatile uint16_t vuint16;
typedef volatile uint8_t vuint8;
/* ------------------------ Defines --------------------------------------- */
#define portVECTOR_TABLE __RAMVEC
#define portVECTOR_SYSCALL ( 32 + portTRAP_YIELD )
#define portVECTOR_TIMER ( 64 + 36 )
#define MCF_PIT_PRESCALER 512UL
#define MCF_PIT_TIMER_TICKS ( FSYS_2 / MCF_PIT_PRESCALER )
#define MCF_PIT_MODULUS_REGISTER(freq) ( MCF_PIT_TIMER_TICKS / ( freq ) - 1UL)
#define MCF_PIT_PMR0 ( *( vuint16 * )( void * )( &__IPSBAR[ 0x150002 ] ) )
#define MCF_PIT_PCSR0 ( *( vuint16 * )( void * )( &__IPSBAR[ 0x150000 ] ) )
#define MCF_PIT_PCSR_PRE(x) ( ( ( x ) & 0x000F ) << 8 )
#define MCF_PIT_PCSR_EN ( 0x0001 )
#define MCF_PIT_PCSR_RLD ( 0x0002 )
#define MCF_PIT_PCSR_PIF ( 0x0004 )
#define MCF_PIT_PCSR_PIE ( 0x0008 )
#define MCF_PIT_PCSR_OVW ( 0x0010 )
#define MCF_INTC0_ICR36 ( *( vuint8 * )( void * )( &__IPSBAR[ 0x000C64 ] ) )
#define MCF_INTC0_IMRH ( *( vuint32 * )( void * )( &__IPSBAR[ 0x000C08 ] ) )
#define MCF_INTC0_IMRH_INT_MASK36 ( 0x00000010 )
#define MCF_INTC0_IMRH_MASKALL ( 0x00000001 )
#define MCF_INTC0_ICRn_IP(x) ( ( ( x ) & 0x07 ) << 0 )
#define MCF_INTC0_ICRn_IL(x) ( ( ( x ) & 0x07 ) << 3 )
#define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
#define portINITIAL_CRITICAL_NESTING ( ( uint32_t ) 10 )
/* ------------------------ Static variables ------------------------------ */
volatile uint32_t ulCriticalNesting = portINITIAL_CRITICAL_NESTING;
/* ------------------------ Static functions ------------------------------ */
#if configUSE_PREEMPTION == 0
static void prvPortPreemptiveTick ( void ) __attribute__ ((interrupt_handler));
#else
static void prvPortPreemptiveTick ( void );
#endif
/* ------------------------ Start implementation -------------------------- */
StackType_t *
pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode,
void *pvParameters )
{
/* Place the parameter on the stack in the expected location. */
*pxTopOfStack = ( StackType_t ) pvParameters;
pxTopOfStack--;
/* Place dummy return address on stack. Tasks should never terminate so
* we can set this to anything. */
*pxTopOfStack = ( StackType_t ) 0;
pxTopOfStack--;
/* Create a Motorola Coldfire exception stack frame. First comes the return
* address. */
*pxTopOfStack = ( StackType_t ) pxCode;
pxTopOfStack--;
/* Format, fault-status, vector number for exception stack frame. Task
* run in supervisor mode. */
*pxTopOfStack = 0x40002000UL | ( portVECTOR_SYSCALL + 32 ) << 18;
pxTopOfStack--;
/* Set the initial critical section nesting counter to zero. This value
* is used to restore the value of ulCriticalNesting. */
*pxTopOfStack = 0;
*pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA6; /* A6 / FP */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA5; /* A5 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA4; /* A4 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA3; /* A3 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA2; /* A2 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA1; /* A1 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xA0; /* A0 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD7; /* D7 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD6; /* D6 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD5; /* D5 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD4; /* D4 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD3; /* D3 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD2; /* D2 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD1; /* D1 */
pxTopOfStack--;
*pxTopOfStack = ( StackType_t ) 0xD0; /* D0 */
return pxTopOfStack;
}
/*
* Called by portYIELD() or taskYIELD() to manually force a context switch.
*/
static void
prvPortYield( void )
{
asm volatile ( "move.w #0x2700, %sr\n\t" );
#if _GCC_USES_FP == 1
asm volatile ( "unlk %fp\n\t" );
#endif
/* Perform the context switch. First save the context of the current task. */
portSAVE_CONTEXT( );
/* Find the highest priority task that is ready to run. */
vTaskSwitchContext( );
/* Restore the context of the new task. */
portRESTORE_CONTEXT( );
}
#if configUSE_PREEMPTION == 0
/*
* The ISR used for the scheduler tick depends on whether the cooperative or
* the preemptive scheduler is being used.
*/
static void
prvPortPreemptiveTick ( void )
{
/* The cooperative scheduler requires a normal IRQ service routine to
* simply increment the system tick.
*/
xTaskIncrementTick();
MCF_PIT_PCSR0 |= MCF_PIT_PCSR_PIF;
}
#else
static void
prvPortPreemptiveTick( void )
{
asm volatile ( "move.w #0x2700, %sr\n\t" );
#if _GCC_USES_FP == 1
asm volatile ( "unlk %fp\n\t" );
#endif
portSAVE_CONTEXT( );
MCF_PIT_PCSR0 |= MCF_PIT_PCSR_PIF;
if( xTaskIncrementTick() != pdFALSE )
{
vTaskSwitchContext( );
}
portRESTORE_CONTEXT( );
}
#endif
void
vPortEnterCritical()
{
/* FIXME: We should store the old IPL here - How are we supposed to do
* this.
*/
( void )portSET_IPL( portIPL_MAX );
/* 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()
{
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 )
{
( void )portSET_IPL( 0 );
}
}
}
BaseType_t
xPortStartScheduler( void )
{
extern void ( *portVECTOR_TABLE[ ] ) ( );
/* Add entry in vector table for yield system call. */
portVECTOR_TABLE[ portVECTOR_SYSCALL ] = prvPortYield;
/* Add entry in vector table for periodic timer. */
portVECTOR_TABLE[ portVECTOR_TIMER ] = prvPortPreemptiveTick;
/* Configure the timer for the system clock. */
if ( configTICK_RATE_HZ > 0)
{
/* Configure prescaler */
MCF_PIT_PCSR0 = MCF_PIT_PCSR_PRE( 0x9 ) | MCF_PIT_PCSR_RLD | MCF_PIT_PCSR_OVW;
/* Initialize the periodic timer interrupt. */
MCF_PIT_PMR0 = MCF_PIT_MODULUS_REGISTER( configTICK_RATE_HZ );
/* Configure interrupt priority and level and unmask interrupt. */
MCF_INTC0_ICR36 = MCF_INTC0_ICRn_IL( 0x1 ) | MCF_INTC0_ICRn_IP( 0x1 );
MCF_INTC0_IMRH &= ~( MCF_INTC0_IMRH_INT_MASK36 | MCF_INTC0_IMRH_MASKALL );
/* Enable interrupts */
MCF_PIT_PCSR0 |= MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_EN | MCF_PIT_PCSR_PIF;
}
/* Restore the context of the first task that is going to run. */
portRESTORE_CONTEXT( );
/* Should not get here. */
return pdTRUE;
}
void
vPortEndScheduler( void )
{
}