/*
    FreeRTOS V7.5.0 - Copyright (C) 2013 Real Time Engineers Ltd.

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that has become a de facto standard.             *
     *                                                                       *
     *    Help yourself get started quickly and support the FreeRTOS         *
     *    project by purchasing a FreeRTOS tutorial book, reference          *
     *    manual, or both from: http://www.FreeRTOS.org/Documentation        *
     *                                                                       *
     *    Thank you!                                                         *
     *                                                                       *
    ***************************************************************************

    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 modification 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.  Full license text is available from the following
    link: http://www.freertos.org/a00114.html

    1 tab == 4 spaces!

    ***************************************************************************
     *                                                                       *
     *    Having a problem?  Start by reading the FAQ "My application does   *
     *    not run, what could be wrong?"                                     *
     *                                                                       *
     *    http://www.FreeRTOS.org/FAQHelp.html                               *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org - Documentation, books, training, latest versions,
    license and Real Time Engineers Ltd. contact details.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
    Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and middleware.

    http://www.SafeRTOS.com - High Integrity Systems also provide a safety
    engineered and independently SIL3 certified version for use in safety and
    mission critical applications that require provable dependability.

    1 tab == 4 spaces!
*/

/* Standard includes. */
#include <stdlib.h>

/* Kernel includes. */
#include "FreeRTOS.h"
#include "task.h"

/* Machine includes */
#include <machine/counter.h>
#include <machine/ic.h>
/*-----------------------------------------------------------*/

/* The initial PSR has the Previous Interrupt Enabled (PIEN) flag set. */
#define portINITIAL_PSR			( 0x00020000 )

/*-----------------------------------------------------------*/

/*
 * Perform any hardware configuration necessary to generate the tick interrupt.
 */
static void prvSetupTimerInterrupt( void );
/*-----------------------------------------------------------*/

portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE * pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
{
	/* Make space on the stack for the context - this leaves a couple of spaces
	empty.  */
	pxTopOfStack -= 20;

	/* Fill the registers with known values to assist debugging. */
	pxTopOfStack[ 16 ] = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
	pxTopOfStack[ 15 ] = portINITIAL_PSR;
	pxTopOfStack[ 14 ] = ( unsigned long ) pxCode;
	pxTopOfStack[ 13 ] = 0x00000000UL; /* R15. */
	pxTopOfStack[ 12 ] = 0x00000000UL; /* R14. */
	pxTopOfStack[ 11 ] = 0x0d0d0d0dUL;
	pxTopOfStack[ 10 ] = 0x0c0c0c0cUL;
	pxTopOfStack[ 9 ] = 0x0b0b0b0bUL;
	pxTopOfStack[ 8 ] = 0x0a0a0a0aUL;
	pxTopOfStack[ 7 ] = 0x09090909UL;
	pxTopOfStack[ 6 ] = 0x08080808UL;
	pxTopOfStack[ 5 ] = 0x07070707UL;
	pxTopOfStack[ 4 ] = 0x06060606UL;
	pxTopOfStack[ 3 ] = 0x05050505UL;
	pxTopOfStack[ 2 ] = 0x04040404UL;
	pxTopOfStack[ 1 ] = 0x03030303UL;
	pxTopOfStack[ 0 ] = ( unsigned long ) pvParameters;

	return pxTopOfStack;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xPortStartScheduler( void )
{
	/* Set-up the timer interrupt. */
	prvSetupTimerInterrupt();

	/* Enable the TRAP yield. */
	irq[ portIRQ_TRAP_YIELD ].ien = 1;
	irq[ portIRQ_TRAP_YIELD ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;

	/* Integrated Interrupt Controller: Enable all interrupts. */
	ic->ien = 1;

	/* Restore callee saved registers. */
	portRESTORE_CONTEXT();

	/* Should not get here. */
	return 0;
}
/*-----------------------------------------------------------*/

static void prvSetupTimerInterrupt( void )
{
	/* Enable timer interrupts */
	counter1->reload = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1;
	counter1->value = counter1->reload;
	counter1->mask = 1;

	/* Set the IRQ Handler priority and enable it. */
	irq[ IRQ_COUNTER1 ].ien = 1;
	irq[ IRQ_COUNTER1 ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
}
/*-----------------------------------------------------------*/

/* Trap 31 handler. */
void interrupt31_handler( void ) __attribute__((naked));
void interrupt31_handler( void )
{
	portSAVE_CONTEXT();
	__asm volatile ( "call vTaskSwitchContext" );
	portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/

static void prvProcessTick( void ) __attribute__((noinline));
static void prvProcessTick( void )
{
	if( xTaskIncrementTick() != pdFALSE )
	{
		vTaskSwitchContext();
	}
		
	/* Clear the Tick Interrupt. */
	counter1->expired = 0;
}
/*-----------------------------------------------------------*/

/* Timer 1 interrupt handler, used for tick interrupt. */
void interrupt7_handler( void ) __attribute__((naked));
void interrupt7_handler( void )
{
	portSAVE_CONTEXT();
	prvProcessTick();
	portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* Nothing to do. Unlikely to want to end. */
}
/*-----------------------------------------------------------*/