/*
    FreeRTOS V7.4.1 - 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.
*/


/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. 

NOTE:  This driver is primarily to test the scheduler functionality.  It does
not effectively use the buffers or DMA and is therefore not intended to be
an example of an efficient driver. */

/* Standard include file. */
#include <stdlib.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"

/* Demo app include files. */
#include "serial.h"

/* Hardware setup. */
#define serOUTPUT						0
#define serINPUT						1
#define serLOW_SPEED					0
#define serONE_STOP_BIT					0
#define serEIGHT_DATA_BITS_NO_PARITY	0
#define serNORMAL_IDLE_STATE			0
#define serAUTO_BAUD_OFF				0
#define serLOOPBACK_OFF					0
#define serWAKE_UP_DISABLE				0
#define serNO_HARDWARE_FLOW_CONTROL		0
#define serSTANDARD_IO					0
#define serNO_IRDA						0
#define serCONTINUE_IN_IDLE_MODE		0
#define serUART_ENABLED					1
#define serINTERRUPT_ON_SINGLE_CHAR		0
#define serTX_ENABLE					1
#define serINTERRUPT_ENABLE				1
#define serINTERRUPT_DISABLE			0
#define serCLEAR_FLAG					0
#define serSET_FLAG						1


/* The queues used to communicate between tasks and ISR's. */
static xQueueHandle xRxedChars; 
static xQueueHandle xCharsForTx; 

static portBASE_TYPE xTxHasEnded;
/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
char cChar;

	/* Create the queues used by the com test task. */
	xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
	xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );

	/* Setup the UART. */
	U2MODEbits.BRGH		= serLOW_SPEED;
	U2MODEbits.STSEL	= serONE_STOP_BIT;
	U2MODEbits.PDSEL	= serEIGHT_DATA_BITS_NO_PARITY;
	U2MODEbits.RXINV	= serNORMAL_IDLE_STATE;
	U2MODEbits.ABAUD	= serAUTO_BAUD_OFF;
	U2MODEbits.LPBACK	= serLOOPBACK_OFF;
	U2MODEbits.WAKE		= serWAKE_UP_DISABLE;
	U2MODEbits.UEN		= serNO_HARDWARE_FLOW_CONTROL;
	U2MODEbits.IREN		= serNO_IRDA;
	U2MODEbits.USIDL	= serCONTINUE_IN_IDLE_MODE;
	U2MODEbits.UARTEN	= serUART_ENABLED;

	U2BRG = (unsigned short)(( (float)configCPU_CLOCK_HZ / ( (float)16 * (float)ulWantedBaud ) ) - (float)0.5);

	U2STAbits.URXISEL	= serINTERRUPT_ON_SINGLE_CHAR;
	U2STAbits.UTXEN		= serTX_ENABLE;
	U2STAbits.UTXINV	= serNORMAL_IDLE_STATE;
	U2STAbits.UTXISEL0	= serINTERRUPT_ON_SINGLE_CHAR;
	U2STAbits.UTXISEL1	= serINTERRUPT_ON_SINGLE_CHAR;

	/* It is assumed that this function is called prior to the scheduler being
	started.  Therefore interrupts must not be allowed to occur yet as they
	may attempt to perform a context switch. */
	portDISABLE_INTERRUPTS();

	IFS1bits.U2RXIF = serCLEAR_FLAG;
	IFS1bits.U2TXIF = serCLEAR_FLAG;
	IPC7bits.U2RXIP = configKERNEL_INTERRUPT_PRIORITY;
	IPC7bits.U2TXIP = configKERNEL_INTERRUPT_PRIORITY;
	IEC1bits.U2TXIE = serINTERRUPT_ENABLE;
	IEC1bits.U2RXIE = serINTERRUPT_ENABLE;

	/* Clear the Rx buffer. */
	while( U2STAbits.URXDA == serSET_FLAG )
	{
		cChar = U2RXREG;
	}

	xTxHasEnded = pdTRUE;

	return NULL;
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
{
	/* Only one port is supported. */
	( void ) pxPort;

	/* Get the next character from the buffer.  Return false if no characters
	are available or arrive before xBlockTime expires. */
	if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
	{
		return pdTRUE;
	}
	else
	{
		return pdFALSE;
	}
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
{
	/* Only one port is supported. */
	( void ) pxPort;

	/* Return false if after the block time there is no room on the Tx queue. */
	if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
	{
		return pdFAIL;
	}

	/* A critical section should not be required as xTxHasEnded will not be
	written to by the ISR if it is already 0 (is this correct?). */
	if( xTxHasEnded )
	{
		xTxHasEnded = pdFALSE;
		IFS1bits.U2TXIF = serSET_FLAG;
	}

	return pdPASS;
}
/*-----------------------------------------------------------*/

void vSerialClose( xComPortHandle xPort )
{
}
/*-----------------------------------------------------------*/

void __attribute__((__interrupt__, auto_psv)) _U2RXInterrupt( void )
{
char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* Get the character and post it on the queue of Rxed characters.
	If the post causes a task to wake force a context switch as the woken task
	may have a higher priority than the task we have interrupted. */
	IFS1bits.U2RXIF = serCLEAR_FLAG;
	while( U2STAbits.URXDA )
	{
		cChar = U2RXREG;
		xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
	}

	if( xHigherPriorityTaskWoken != pdFALSE )
	{
		taskYIELD();
	}
}
/*-----------------------------------------------------------*/

void __attribute__((__interrupt__, auto_psv)) _U2TXInterrupt( void )
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* If the transmit buffer is full we cannot get the next character.
	Another interrupt will occur the next time there is space so this does
	not matter. */
	IFS1bits.U2TXIF = serCLEAR_FLAG;
	while( !( U2STAbits.UTXBF ) )
	{
		if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
		{
			/* Send the next character queued for Tx. */
			U2TXREG = cChar;
		}
		else
		{
			/* Queue empty, nothing to send. */
			xTxHasEnded = pdTRUE;
			break;
		}
	}

	if( xHigherPriorityTaskWoken != pdFALSE )
	{
		taskYIELD();
	}
}