port.c

FreeRTOS - V5.1.1 Last Update: Nov 20 2008 http://sourceforge.net/projects/freertos/

/*This file has been prepared for Doxygen automatic documentation generation.*/
/*! \file *********************************************************************
 *
 * \brief FreeRTOS port source for AVR32 UC3.
 *
 * - Compiler:           GNU GCC for AVR32
 * - Supported devices:  All AVR32 devices can be used.
 * - AppNote:
 *
 * \author               Atmel Corporation: http://www.atmel.com \n
 *                       Support and FAQ: http://support.atmel.no/
 *
 *****************************************************************************/

/*
	FreeRTOS.org V5.1.1 - Copyright (C) 2003-2008 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org 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.org 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.org; 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.org, 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.

    ***************************************************************************
    ***************************************************************************
    *                                                                         *
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	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.

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*/


/* Standard includes. */
#include <sys/cpu.h>
#include <sys/usart.h>
#include <malloc.h>

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"

/* AVR32 UC3 includes. */
#include <avr32/io.h>
#include "gpio.h"
#if( configTICK_USE_TC==1 )
	#include "tc.h"
#endif


/* Constants required to setup the task context. */
#define portINITIAL_SR            ( ( portSTACK_TYPE ) 0x00400000 ) /* AVR32 : [M2:M0]=001 I1M=0 I0M=0, GM=0 */
#define portINSTRUCTION_SIZE      ( ( portSTACK_TYPE ) 0 )

/* Each task maintains its own critical nesting variable. */
#define portNO_CRITICAL_NESTING   ( ( unsigned portLONG ) 0 )
volatile unsigned portLONG ulCriticalNesting = 9999UL;

#if( configTICK_USE_TC==0 )
	static void prvScheduleNextTick( void );
#else
	static void prvClearTcInt( void );
#endif

/* Setup the timer to generate the tick interrupts. */
static void prvSetupTimerInterrupt( void );

/*-----------------------------------------------------------*/

/*
 * Low-level initialization routine called during startup, before the main
 * function.
 * This version comes in replacement to the default one provided by Newlib.
 * Newlib's _init_startup only calls init_exceptions, but Newlib's exception
 * vectors are not compatible with the SCALL management in the current FreeRTOS
 * port. More low-level initializations are besides added here.
 */
void _init_startup(void)
{
	/* Import the Exception Vector Base Address. */
	extern void _evba;

	#if configHEAP_INIT
		extern void __heap_start__;
		extern void __heap_end__;
		portBASE_TYPE *pxMem;
	#endif

	/* Load the Exception Vector Base Address in the corresponding system register. */
	Set_system_register( AVR32_EVBA, ( int ) &_evba );

	/* Enable exceptions. */
	ENABLE_ALL_EXCEPTIONS();

	/* Initialize interrupt handling. */
	INTC_init_interrupts();

	#if configHEAP_INIT

		/* Initialize the heap used by malloc. */
		for( pxMem = &__heap_start__; pxMem < ( portBASE_TYPE * )&__heap_end__; )
		{
			*pxMem++ = 0xA5A5A5A5;
		}

	#endif

	/* Give the used CPU clock frequency to Newlib, so it can work properly. */
	set_cpu_hz( configCPU_CLOCK_HZ );

	/* Code section present if and only if the debug trace is activated. */
	#if configDBG
	{
		static const gpio_map_t DBG_USART_GPIO_MAP =
		{
			{ configDBG_USART_RX_PIN, configDBG_USART_RX_FUNCTION },
			{ configDBG_USART_TX_PIN, configDBG_USART_TX_FUNCTION }
		};

		/* Initialize the USART used for the debug trace with the configured parameters. */
		set_usart_base( ( void * ) configDBG_USART );
		gpio_enable_module( DBG_USART_GPIO_MAP,
		                    sizeof( DBG_USART_GPIO_MAP ) / sizeof( DBG_USART_GPIO_MAP[0] ) );
		usart_init( configDBG_USART_BAUDRATE );
	}
	#endif
}
/*-----------------------------------------------------------*/

/*
 * malloc, realloc and free are meant to be called through respectively
 * pvPortMalloc, pvPortRealloc and vPortFree.
 * The latter functions call the former ones from within sections where tasks
 * are suspended, so the latter functions are task-safe. __malloc_lock and
 * __malloc_unlock use the same mechanism to also keep the former functions
 * task-safe as they may be called directly from Newlib's functions.
 * However, all these functions are interrupt-unsafe and SHALL THEREFORE NOT BE
 * CALLED FROM WITHIN AN INTERRUPT, because __malloc_lock and __malloc_unlock do
 * not call portENTER_CRITICAL and portEXIT_CRITICAL in order not to disable
 * interrupts during memory allocation management as this may be a very time-
 * consuming process.
 */

/*
 * Lock routine called by Newlib on malloc / realloc / free entry to guarantee a
 * safe section as memory allocation management uses global data.
 * See the aforementioned details.
 */
void __malloc_lock(struct _reent *ptr)
{
	vTaskSuspendAll();
}

/*
 * Unlock routine called by Newlib on malloc / realloc / free exit to guarantee
 * a safe section as memory allocation management uses global data.
 * See the aforementioned details.
 */
void __malloc_unlock(struct _reent *ptr)
{
	xTaskResumeAll();
}
/*-----------------------------------------------------------*/

/* Added as there is no such function in FreeRTOS. */
void *pvPortRealloc( void *pv, size_t xWantedSize )
{
void *pvReturn;

	vTaskSuspendAll();
	{
		pvReturn = realloc( pv, xWantedSize );
	}
	xTaskResumeAll();

	return pvReturn;
}
/*-----------------------------------------------------------*/

/* The cooperative scheduler requires a normal IRQ service routine to
simply increment the system tick. */
/* The preemptive scheduler is defined as "naked" as the full context is saved
on entry as part of the context switch. */
__attribute__((__naked__)) static void vTick( void )
{
	/* Save the context of the interrupted task. */
	portSAVE_CONTEXT_OS_INT();

	#if( configTICK_USE_TC==1 )
		/* Clear the interrupt flag. */
		prvClearTcInt();
	#else
		/* Schedule the COUNT&COMPARE match interrupt in (configCPU_CLOCK_HZ/configTICK_RATE_HZ)
		clock cycles from now. */
		prvScheduleNextTick();
	#endif

	/* Because FreeRTOS is not supposed to run with nested interrupts, put all OS