/*
    FreeRTOS V7.4.0 - Copyright (C) 2013 Real Time Engineers Ltd.

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    ***************************************************************************
     *                                                                       *
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    ***************************************************************************


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    FreeRTOS is free software; you can redistribute it and/or modify it under
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    ***************************************************************************
     *                                                                       *
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*/

/*
	BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "semphr.h"

/* Library includes. */
#include "stm32f10x_lib.h"

/* Demo application includes. */
#include "serial.h"
/*-----------------------------------------------------------*/

/* Misc defines. */
#define serINVALID_QUEUE				( ( xQueueHandle ) 0 )
#define serNO_BLOCK						( ( portTickType ) 0 )
#define serTX_BLOCK_TIME				( 40 / portTICK_RATE_MS )

/*-----------------------------------------------------------*/

/* The queue used to hold received characters. */
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;

/*-----------------------------------------------------------*/

/* UART interrupt handler. */
void vUARTInterruptHandler( void );

/*-----------------------------------------------------------*/

/*
 * See the serial2.h header file.
 */
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
xComPortHandle xReturn;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;

	/* Create the queues used to hold Rx/Tx characters. */
	xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
	xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
	
	/* If the queue/semaphore was created correctly then setup the serial port
	hardware. */
	if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
	{
		/* Enable USART1 clock */
		RCC_APB2PeriphClockCmd( RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE );	

		/* Configure USART1 Rx (PA10) as input floating */
		GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
		GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
		GPIO_Init( GPIOA, &GPIO_InitStructure );
		
		/* Configure USART1 Tx (PA9) as alternate function push-pull */
		GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
		GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
		GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
		GPIO_Init( GPIOA, &GPIO_InitStructure );

		USART_InitStructure.USART_BaudRate = ulWantedBaud;
		USART_InitStructure.USART_WordLength = USART_WordLength_8b;
		USART_InitStructure.USART_StopBits = USART_StopBits_1;
		USART_InitStructure.USART_Parity = USART_Parity_No ;
		USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
		USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
		USART_InitStructure.USART_Clock = USART_Clock_Disable;
		USART_InitStructure.USART_CPOL = USART_CPOL_Low;
		USART_InitStructure.USART_CPHA = USART_CPHA_2Edge;
		USART_InitStructure.USART_LastBit = USART_LastBit_Disable;
		
		USART_Init( USART1, &USART_InitStructure );
		
		USART_ITConfig( USART1, USART_IT_RXNE, ENABLE );
		
		NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQChannel;
		NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = configLIBRARY_KERNEL_INTERRUPT_PRIORITY;
		NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
		NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
		NVIC_Init( &NVIC_InitStructure );
		
		USART_Cmd( USART1, ENABLE );		
	}
	else
	{
		xReturn = ( xComPortHandle ) 0;
	}

	/* This demo file only supports a single port but we have to return
	something to comply with the standard demo header file. */
	return xReturn;
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
{
	/* The port handle is not required as this driver only supports one port. */
	( 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 portCHAR * const pcString, unsigned portSHORT usStringLength )
{
signed portCHAR *pxNext;

	/* A couple of parameters that this port does not use. */
	( void ) usStringLength;
	( void ) pxPort;

	/* NOTE: This implementation does not handle the queue being full as no
	block time is used! */

	/* The port handle is not required as this driver only supports UART1. */
	( void ) pxPort;

	/* Send each character in the string, one at a time. */
	pxNext = ( signed portCHAR * ) pcString;
	while( *pxNext )
	{
		xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
		pxNext++;
	}
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
{
signed portBASE_TYPE xReturn;

	if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
	{
		xReturn = pdPASS;
		USART_ITConfig( USART1, USART_IT_TXE, ENABLE );
	}
	else
	{
		xReturn = pdFAIL;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

void vSerialClose( xComPortHandle xPort )
{
	/* Not supported as not required by the demo application. */
}
/*-----------------------------------------------------------*/

void vUARTInterruptHandler( void )
{
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
portCHAR cChar;

	if( USART_GetITStatus( USART1, USART_IT_TXE ) == SET )
	{
		/* The interrupt was caused by the THR becoming empty.  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
			THR now. */
			USART_SendData( USART1, cChar );
		}
		else
		{
			USART_ITConfig( USART1, USART_IT_TXE, DISABLE );		
		}		
	}
	
	if( USART_GetITStatus( USART1, USART_IT_RXNE ) == SET )
	{
		cChar = USART_ReceiveData( USART1 );
		xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
	}	
	
	portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
}