/*
    FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.

    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
    http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS tutorial books are available in pdf and paperback.        *
     *    Complete, revised, and edited pdf reference manuals are also       *
     *    available.                                                         *
     *                                                                       *
     *    Purchasing FreeRTOS documentation will not only help you, by       *
     *    ensuring you get running as quickly as possible and with an        *
     *    in-depth knowledge of how to use FreeRTOS, it will also help       *
     *    the FreeRTOS project to continue with its mission of providing     *
     *    professional grade, cross platform, de facto standard solutions    *
     *    for microcontrollers - completely free of charge!                  *
     *                                                                       *
     *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
     *                                                                       *
     *    Thank you for using FreeRTOS, and 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 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.  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 Real Time Engineers Ltd., contact details for whom are available
    on the FreeRTOS WEB site.

    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, and our new
    fully thread aware and reentrant UDP/IP stack.

    http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High 
    Integrity Systems, who sell the code with commercial support, 
    indemnification and middleware, under the OpenRTOS brand.
    
    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.
*/

/*
 * This file implements functions to access and manipulate the PIC32 hardware
 * without reliance on third party library functions that may be liable to
 * change.
 */

/* FreeRTOS includes. */
#include "FreeRTOS.h"

/* Demo includes. */
#include "ConfigPerformance.h"

/* Hardware specific definitions. */
#define hwCHECON_PREFEN_BITS	  		( 0x03UL << 0x04UL )
#define hwCHECON_WAIT_STAT_BITS			( 0x07UL << 0UL )
#define hwMAX_FLASH_SPEED		  		( 30000000UL )
#define hwPERIPHERAL_CLOCK_DIV_BY_2		( 1UL << 0x13UL )
#define hwUNLOCK_KEY_0					( 0xAA996655UL )
#define hwUNLOCK_KEY_1					( 0x556699AAUL )
#define hwLOCK_KEY						( 0x33333333UL )
#define hwGLOBAL_INTERRUPT_BIT			( 0x01UL )
#define hwBEV_BIT 						( 0x00400000 )
#define hwEXL_BIT 						( 0x00000002 )
#define hwIV_BIT 						( 0x00800000 )

/*
 * Set the flash wait states for the configured CPU clock speed.
 */
static void prvConfigureWaitStates( void );

/*
 * Use a divisor of 2 on the peripheral bus.
 */
static void prvConfigurePeripheralBus( void );

/*
 * Enable the cache.
 */
static void __attribute__ ((nomips16)) prvKSeg0CacheOn( void );

/*-----------------------------------------------------------*/

void vHardwareConfigurePerformance( void )
{
unsigned long ulStatus;
#ifdef _PCACHE
	unsigned long ulCacheStatus;
#endif

	/* Disable interrupts - not taskDISABLE_INTERRUPTS() cannot be used here as
	FreeRTOS does not globally disable interrupt. */
	ulStatus = _CP0_GET_STATUS();
	_CP0_SET_STATUS( ulStatus & ~hwGLOBAL_INTERRUPT_BIT );

	prvConfigurePeripheralBus();
	prvConfigureWaitStates();

	/* Disable DRM wait state. */
	BMXCONCLR = _BMXCON_BMXWSDRM_MASK;

	#ifdef _PCACHE
	{
		/* Read the current CHECON value. */
		ulCacheStatus = CHECON;

		/* All the PREFEN bits are being set, so no need to clear first. */
		ulCacheStatus |= hwCHECON_PREFEN_BITS;

		/* Write back the new value. */
		CHECON = ulCacheStatus;
		prvKSeg0CacheOn();
	}
	#endif

	/* Reset the status register back to its original value so the original
	interrupt enable status is retored. */
	_CP0_SET_STATUS( ulStatus );
}
/*-----------------------------------------------------------*/

void vHardwareUseMultiVectoredInterrupts( void )
{
unsigned long ulStatus, ulCause;
extern unsigned long _ebase_address[];

	/* Get current status. */
	ulStatus = _CP0_GET_STATUS();

	/* Disable interrupts. */
	ulStatus &= ~hwGLOBAL_INTERRUPT_BIT;

	/* Set BEV bit. */
	ulStatus |= hwBEV_BIT;

	/* Write status back. */
	_CP0_SET_STATUS( ulStatus );

	/* Setup EBase. */
	_CP0_SET_EBASE( ( unsigned long ) _ebase_address );
	
	/* Space vectors by 0x20 bytes. */
	_CP0_XCH_INTCTL( 0x20 );

	/* Set the IV bit in the CAUSE register. */
	ulCause = _CP0_GET_CAUSE();
	ulCause |= hwIV_BIT;
	_CP0_SET_CAUSE( ulCause );

	/* Clear BEV and EXL bits in status. */
	ulStatus &= ~( hwBEV_BIT | hwEXL_BIT );
	_CP0_SET_STATUS( ulStatus );

	/* Set MVEC bit. */
	INTCONbits.MVEC = 1;
	
	/* Finally enable interrupts again. */
	ulStatus |= hwGLOBAL_INTERRUPT_BIT;
	_CP0_SET_STATUS( ulStatus );
}
/*-----------------------------------------------------------*/

static void prvConfigurePeripheralBus( void )
{
unsigned long ulDMAStatus;
__OSCCONbits_t xOSCCONBits;

	/* Unlock after suspending. */
	ulDMAStatus = DMACONbits.SUSPEND;
	if( ulDMAStatus == 0 )
	{
		DMACONSET = _DMACON_SUSPEND_MASK;

		/* Wait until actually suspended. */
		while( DMACONbits.SUSPEND == 0 );
	}

	SYSKEY = 0;
	SYSKEY = hwUNLOCK_KEY_0;
	SYSKEY = hwUNLOCK_KEY_1;

	/* Read to start in sync. */
	xOSCCONBits.w = OSCCON;
	xOSCCONBits.PBDIV = 0;
	xOSCCONBits.w |= hwPERIPHERAL_CLOCK_DIV_BY_2;

	/* Write back. */
	OSCCON = xOSCCONBits.w;

	/* Ensure the write occurred. */
	xOSCCONBits.w = OSCCON;

	/* Lock again. */
	SYSKEY = hwLOCK_KEY;

	/* Resume DMA activity. */
	if( ulDMAStatus == 0 )
	{
		DMACONCLR=_DMACON_SUSPEND_MASK;
	}
}
/*-----------------------------------------------------------*/

static void prvConfigureWaitStates( void )
{
unsigned long ulInterruptStatus, ulSystemClock = configCPU_CLOCK_HZ - 1;
unsigned long ulWaitStates, ulCHECONVal;

	/* 1 wait state for every hwMAX_FLASH_SPEED MHz. */
	ulWaitStates = 0;

	while( ulSystemClock > hwMAX_FLASH_SPEED )
	{
		ulWaitStates++;
		ulSystemClock -= hwMAX_FLASH_SPEED;
	}

	/* Obtain current CHECON value. */
	ulCHECONVal = CHECON;

	/* Clear the wait state bits, then set the calculated wait state bits. */
	ulCHECONVal &= ~hwCHECON_WAIT_STAT_BITS;
	ulCHECONVal |= ulWaitStates;

	/* Write back the new value. */
	CHECON = ulWaitStates;
}
/*-----------------------------------------------------------*/

static void __attribute__ ((nomips16)) prvKSeg0CacheOn( void )
{
unsigned long ulValue;

	__asm volatile( "mfc0 %0, $16, 0" :  "=r"( ulValue ) );
	ulValue = ( ulValue & ~0x07) | 0x03;
	__asm volatile( "mtc0 %0, $16, 0" :: "r" ( ulValue ) );
}