/*
    FreeRTOS V9.0.0rc2 - Copyright (C) 2016 Real Time Engineers Ltd.
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    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 on the following
    link: http://www.freertos.org/a00114.html

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that is more than just the market leader, it     *
     *    is the industry's de facto standard.                               *
     *                                                                       *
     *    Help yourself get started quickly while simultaneously helping     *
     *    to support the FreeRTOS project by purchasing a FreeRTOS           *
     *    tutorial book, reference manual, or both:                          *
     *    http://www.FreeRTOS.org/Documentation                              *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
    the FAQ page "My application does not run, what could be wrong?".  Have you
    defined configASSERT()?

    http://www.FreeRTOS.org/support - In return for receiving this top quality
    embedded software for free we request you assist our global community by
    participating in the support forum.

    http://www.FreeRTOS.org/training - Investing in training allows your team to
    be as productive as possible as early as possible.  Now you can receive
    FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
    Ltd, and the world's leading authority on the world's leading RTOS.

    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.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
    Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

    http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
    Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and commercial 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!
*/

/*
 * The comms test Rx and Tx task and co-routine.  See the comments at the top
 * of main.c for full information.
 */


/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "croutine.h"

/* Demo application include files. */
#include "partest.h"

/* Library include files. */
#include "DriverLib.h"

/* The LED's toggled by the various tasks. */
#define commsFAIL_LED			( 7 )
#define commsRX_LED			( 6 )
#define commsTX_LED			( 5 )

/* The length of the queue used to pass received characters to the Comms Rx
task. */
#define commsRX_QUEUE_LEN			( 5 )

/* The baud rate used by the UART comms tasks/co-routine. */
#define commsBAUD_RATE				( 57600 )

/* FIFO setting for the UART.  The FIFO is not used to create a better test. */
#define commsFIFO_SET				( 0x10 )

/* The string that is transmitted on the UART contains sequentially the
characters from commsFIRST_TX_CHAR to commsLAST_TX_CHAR. */
#define commsFIRST_TX_CHAR '0'
#define commsLAST_TX_CHAR 'z'

/* Just used to walk through the program memory in order that some random data
can be generated. */
#define commsTOTAL_PROGRAM_MEMORY ( ( unsigned long * ) ( 8 * 1024 ) )
#define commsFIRST_PROGRAM_BYTES ( ( unsigned long * ) 4 )

/* The time between transmissions of the string on UART 0.   This is pseudo
random in order to generate a bit or randomness to when the interrupts occur.*/
#define commsMIN_TX_DELAY			( 40 / portTICK_PERIOD_MS )
#define commsMAX_TX_DELAY			( ( TickType_t ) 0x7f )
#define commsOFFSET_TIME			( ( TickType_t ) 3 )

/* The time the Comms Rx task should wait to receive a character.  This should
be slightly longer than the time between transmissions.  If we do not receive
a character after this time then there must be an error in the transmission or
the timing of the transmission. */
#define commsRX_DELAY			( commsMAX_TX_DELAY + 20 )


static unsigned portBASE_TYPE uxCommsErrorStatus = pdPASS;

/* The queue used to pass characters out of the ISR. */
static QueueHandle_t xCommsQueue;

/* The next character to transmit. */
static char cNextChar;

/*-----------------------------------------------------------*/

void vSerialInit( void )
{
	/* Create the queue used to communicate between the UART ISR and the Comms
	Rx task. */
	xCommsQueue = xQueueCreate( commsRX_QUEUE_LEN, sizeof( char ) );

	/* Enable the UART.  GPIOA has already been initialised. */
	SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

	/* Set GPIO A0 and A1 as peripheral function.  They are used to output the
	UART signals. */
	GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );

	/* Configure the UART for 8-N-1 operation. */
	UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), commsBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );

	/* We dont want to use the fifo.  This is for test purposes to generate
	as many interrupts as possible. */
	HWREG( UART0_BASE + UART_O_LCR_H ) &= ~commsFIFO_SET;

	/* Enable both Rx and Tx interrupts. */
	HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
	IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
	IntEnable( INT_UART0 );
}
/*-----------------------------------------------------------*/

void vSerialTxCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex )
{
TickType_t xDelayPeriod;
static unsigned long *pulRandomBytes = commsFIRST_PROGRAM_BYTES;

	/* Co-routine MUST start with a call to crSTART. */
	crSTART( xHandle );

	for(;;)
    {	
		/* Was the previously transmitted string received correctly? */
		if( uxCommsErrorStatus != pdPASS )
		{
			/* An error was encountered so set the error LED. */
			vParTestSetLED( commsFAIL_LED, pdTRUE );
		}

		/* The next character to Tx is the first in the string. */
		cNextChar = commsFIRST_TX_CHAR;

		UARTIntDisable( UART0_BASE, UART_INT_TX );
		{
			/* Send the first character. */
			if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
			{
				HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
			}

			/* Move the variable to the char to Tx on so the ISR transmits
			the next character in the string once this one has completed. */
			cNextChar++;
		}
		UARTIntEnable(UART0_BASE, UART_INT_TX);

		/* Toggle the LED to show a new string is being transmitted. */
        vParTestToggleLED( commsTX_LED );

		/* Delay before we start the string off again.  A pseudo-random delay
		is used as this will provide a better test. */
		xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );

		pulRandomBytes++;
		if( pulRandomBytes > commsTOTAL_PROGRAM_MEMORY )
		{
			pulRandomBytes = commsFIRST_PROGRAM_BYTES;
		}

		/* Make sure we don't wait too long... */
		xDelayPeriod &= commsMAX_TX_DELAY;

		/* ...but we do want to wait. */
		if( xDelayPeriod < commsMIN_TX_DELAY )
		{
			xDelayPeriod = commsMIN_TX_DELAY;
		}

		/* Block for the random(ish) time. */
		crDELAY( xHandle, xDelayPeriod );
    }

	/* Co-routine MUST end with a call to crEND. */
	crEND();
}
/*-----------------------------------------------------------*/

void vUART_ISR( void )
{
unsigned long ulStatus;
char cRxedChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* What caused the interrupt. */
	ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );

	/* Clear the interrupt. */
	UARTIntClear( UART0_BASE, ulStatus );

	/* Was an Rx interrpt pending? */
	if( ulStatus & UART_INT_RX )
	{
		if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
		{
			/* Get the char from the buffer and post it onto the queue of
			Rxed chars.  Posting the character should wake the task that is
			blocked on the queue waiting for characters. */
			cRxedChar = ( char ) HWREG( UART0_BASE + UART_O_DR );
			xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
		}		
	}

	/* Was a Tx interrupt pending? */
	if( ulStatus & UART_INT_TX )
	{
		/* Send the next character in the string.  We are not using the FIFO. */
		if( cNextChar <= commsLAST_TX_CHAR )
		{
			if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
			{
				HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
			}
			cNextChar++;
		}
	}
	
	/* If a task was woken by the character being received then we force
	a context switch to occur in case the task is of higher priority than
	the currently executing task (i.e. the task that this interrupt
	interrupted.) */
	portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/

void vCommsRxTask( void * pvParameters )
{
static char cRxedChar, cExpectedChar;

	/* Set the char we expect to receive to the start of the string. */
	cExpectedChar = commsFIRST_TX_CHAR;

	for( ;; )
	{
		/* Wait for a character to be received. */
		xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, commsRX_DELAY );

		/* Was the character recived (if any) the expected character. */
		if( cRxedChar != cExpectedChar )
		{
			/* Got an unexpected character.  This can sometimes occur when
			reseting the system using the debugger leaving characters already
			in the UART regsters. */
			uxCommsErrorStatus = pdFAIL;

			/* Resync by waiting for the end of the current string. */
			while( cRxedChar != commsLAST_TX_CHAR )
			{
				while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
			}

			/* The next expected character is the start of the string again. */
			cExpectedChar = commsFIRST_TX_CHAR;
		}
		else
		{
			if( cExpectedChar == commsLAST_TX_CHAR )
			{
				/* We have reached the end of the string - we now expect to
				receive the first character in the string again.   The LED is
				toggled to indicate that the entire string was received without
				error. */
				vParTestToggleLED( commsRX_LED );
				cExpectedChar = commsFIRST_TX_CHAR;
			}
			else
			{
				/* We got the expected character, we now expect to receive the
				next character in the string. */
				cExpectedChar++;
			}
		}
	}
}
/*-----------------------------------------------------------*/

unsigned portBASE_TYPE uxGetCommsStatus( void )
{
	return uxCommsErrorStatus;
}