/*
    FreeRTOS V8.2.0rc1 - Copyright (C) 2014 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

    1 tab == 4 spaces!

    ***************************************************************************
     *                                                                       *
     *    Having a problem?  Start by reading the FAQ "My application does   *
     *    not run, what could be wrong?".  Have you defined configASSERT()?  *
     *                                                                       *
     *    http://www.FreeRTOS.org/FAQHelp.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     *
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     *    tutorial book, reference manual, or both:                          *
     *    http://www.FreeRTOS.org/Documentation                              *
     *                                                                       *
    ***************************************************************************

    ***************************************************************************
     *                                                                       *
     *   Investing in training allows your team to be as productive as       *
     *   possible as early as possible, lowering your overall development    *
     *   cost, and enabling you to bring a more robust product to market     *
     *   earlier than would otherwise be possible.  Richard Barry is both    *
     *   the architect and key author of FreeRTOS, and so also the world's   *
     *   leading authority on what is the world's most popular real time     *
     *   kernel for deeply embedded MCU designs.  Obtaining your training    *
     *   from Richard ensures your team will gain directly from his in-depth *
     *   product knowledge and years of usage experience.  Contact Real Time *
     *   Engineers Ltd to enquire about the FreeRTOS Masterclass, presented  *
     *   by Richard Barry:  http://www.FreeRTOS.org/contact
     *                                                                       *
    ***************************************************************************

    ***************************************************************************
     *                                                                       *
     *    You are receiving this top quality software for free.  Please play *
     *    fair and reciprocate by reporting any suspected issues and         *
     *    participating in the community forum:                              *
     *    http://www.FreeRTOS.org/support                                    *
     *                                                                       *
     *    Thank you!                                                         *
     *                                                                       *
    ***************************************************************************

    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.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!
*/

/*  Basic interrupt driven serial port driver for uart1.
*/

/* Standard includes. */
#include <stdlib.h>

/* Kernel includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"

/* Demo application includes. */
#include <machine/uart.h>
#include <machine/ic.h>
#include "serial.h"
/*-----------------------------------------------------------*/

#define comBLOCK_RETRY_TIME				10
/*-----------------------------------------------------------*/

/* The interrupt handlers are naked functions that call C handlers.  The C
handlers are marked as noinline to ensure they work correctly when the
optimiser is on. */
void interrupt5_handler( void ) __attribute__((naked));
static void prvTxHandler( void ) __attribute__((noinline));
void interrupt6_handler( void ) __attribute__((naked));
static void prvRxHandler( void ) __attribute__((noinline));

/*-----------------------------------------------------------*/

/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
	/* Create the queues used to hold Rx and Tx characters. */
	xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
	xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );

	if( ( xRxedChars ) && ( xCharsForTx ) )
	{
		/* Set up interrupts */
		/* tx interrupt will be enabled when we need to send something */
		uart1->tx_mask = 0;
		uart1->rx_mask = 1;
		irq[IRQ_UART1_TX].ien = 1;
		irq[IRQ_UART1_RX].ien = 1;
	}

	return ( xComPortHandle ) 0;
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
{
	/* The port handle is not required as this driver only supports uart1. */
	(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;
	}
}
/*-----------------------------------------------------------*/

void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
{
	int i;
	signed char *pChNext;

	/* Send each character in the string, one at a time. */
	pChNext = ( signed char * )pcString;
	for( i = 0; i < usStringLength; i++ )
	{
		/* Block until character has been transmitted. */
		while( xSerialPutChar( pxPort, *pChNext, comBLOCK_RETRY_TIME ) != pdTRUE ); pChNext++;
	}
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
{
	( void ) pxPort;

	/* Place the character in the queue of characters to be transmitted. */
	if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
	{
		return pdFAIL;
	}

	/* Turn on the Tx interrupt so the ISR will remove the character from the
	   queue and send it. This does not need to be in a critical section as
	   if the interrupt has already removed the character the next interrupt
	   will simply turn off the Tx interrupt again. */
	uart1->tx_mask = 1;

	return pdPASS;
}
/*-----------------------------------------------------------*/

void vSerialClose( xComPortHandle xPort )
{
	/* Not supported as not required by the demo application. */
	( void ) xPort;
}
/*-----------------------------------------------------------*/

/* UART Tx interrupt handler. */
void interrupt5_handler( void )
{
	/* This is a naked function. */
	portSAVE_CONTEXT();
	prvTxHandler();
	portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/

static void prvTxHandler( void )
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* The interrupt was caused by the transmit fifo having space for at least one
	character. Are there any more characters to transmit? */
	if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
	{
		/* A character was retrieved from the queue so can be sent to the uart now. */
		uart1->tx_data = cChar;
	}
	else
	{
		/* Queue empty, nothing to send so turn off the Tx interrupt. */
		uart1->tx_mask = 0;
	}

	/* If an event caused a task to unblock then we call "Yield from ISR" to
	ensure that the unblocked task is the task that executes when the interrupt
	completes if the unblocked task has a priority higher than the interrupted
	task. */
	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/

/* UART Rx interrupt. */
void interrupt6_handler( void )
{
	portSAVE_CONTEXT();
	prvRxHandler();
	portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/

static void prvRxHandler( void )
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* The interrupt was caused by the receiver getting data. */
	cChar = uart1->rx_data;

	xQueueSendFromISR(xRxedChars, &cChar, &xHigherPriorityTaskWoken );

	/* If an event caused a task to unblock then we call "Yield from ISR" to
	ensure that the unblocked task is the task that executes when the interrupt
	completes if the unblocked task has a priority higher than the interrupted
	task. */
	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/