FreeRTOS-Kernel/Demo/MicroBlaze/serial/serial.c

/*
	FreeRTOS V5.4.0 - Copyright (C) 2003-2009 Richard Barry.

	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 exception 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.  
	Alternative commercial license and support terms are also available upon 
	request.  See the licensing section of http://www.FreeRTOS.org for full 
	license details.

	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 along
	with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
	Temple Place, Suite 330, Boston, MA  02111-1307  USA.


	***************************************************************************
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	* See http://www.FreeRTOS.org/Documentation for details                   *
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	Please ensure to read the configuration and relevant port sections of the
	online documentation.

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*/


/* 
	BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART
*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"

/* Demo application includes. */
#include "serial.h"

/* Microblaze driver includes. */
#include "xuartlite_l.h"
#include "xintc_l.h"

/*-----------------------------------------------------------*/

/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static xQueueHandle xRxedChars; 
static xQueueHandle xCharsForTx; 

/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
unsigned portLONG ulControlReg, ulMask;

	/* NOTE: The baud rate used by this driver is determined by the hardware
	parameterization of the UART Lite peripheral, and the baud value passed to
	this function has no effect. */

	/* Create the queues used to hold Rx and Tx characters. */
	xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
	xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );

	if( ( xRxedChars ) && ( xCharsForTx ) )
	{
		/* Disable the interrupt. */
		XUartLite_mDisableIntr( XPAR_RS232_UART_BASEADDR );
		
		/* Flush the fifos. */
		ulControlReg = XIo_In32( XPAR_RS232_UART_BASEADDR + XUL_STATUS_REG_OFFSET );
		XIo_Out32( XPAR_RS232_UART_BASEADDR + XUL_CONTROL_REG_OFFSET, ulControlReg | XUL_CR_FIFO_TX_RESET | XUL_CR_FIFO_RX_RESET );

		/* Enable the interrupt again.  The interrupt controller has not yet been 
		initialised so there is no chance of receiving an interrupt until the 
		scheduler has been started. */
		XUartLite_mEnableIntr( XPAR_RS232_UART_BASEADDR );

		/* Enable the interrupt in the interrupt controller while maintaining 
		all the other bit settings. */
		ulMask = XIntc_In32( ( XPAR_OPB_INTC_0_BASEADDR + XIN_IER_OFFSET ) );
		ulMask |= XPAR_RS232_UART_INTERRUPT_MASK;
		XIntc_Out32( ( XPAR_OPB_INTC_0_BASEADDR + XIN_IER_OFFSET ), ( ulMask ) );
		XIntc_mAckIntr( XPAR_INTC_SINGLE_BASEADDR, 2 );
	}
	
	return ( xComPortHandle ) 0;
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
{
	/* The port handle is not required as this driver only supports one UART. */
	( 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 portCHAR cOutChar, portTickType xBlockTime )
{
portBASE_TYPE xReturn = pdTRUE;

	portENTER_CRITICAL();
	{
		/* If the UART FIFO is full we can block posting the new data on the
		Tx queue. */
		if( XUartLite_mIsTransmitFull( XPAR_RS232_UART_BASEADDR ) )
		{
			if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
			{
				xReturn = pdFAIL;
			}
		}
		/* Otherwise, if there is data already in the queue we should add the
		new data to the back of the queue to ensure the sequencing is 
		maintained. */
		else if( uxQueueMessagesWaiting( xCharsForTx ) )
		{
			if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
			{
				xReturn = pdFAIL;
			}			
		}
		/* If the UART FIFO is not full and there is no data already in the
		queue we can write directly to the FIFO without disrupting the 
		sequence. */
		else
		{
			XIo_Out32( XPAR_RS232_UART_BASEADDR + XUL_TX_FIFO_OFFSET, cOutChar );
		}
	}
	portEXIT_CRITICAL();

	return xReturn;
}
/*-----------------------------------------------------------*/

void vSerialClose( xComPortHandle xPort )
{
	/* Not supported as not required by the demo application. */
	( void ) xPort;
}
/*-----------------------------------------------------------*/

void vSerialISR( void *pvBaseAddress )
{
unsigned portLONG ulISRStatus;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
portCHAR cChar;

	/* Determine the cause of the interrupt. */
    ulISRStatus = XIo_In32( XPAR_RS232_UART_BASEADDR + XUL_STATUS_REG_OFFSET );

    if( ( ulISRStatus & ( XUL_SR_RX_FIFO_FULL | XUL_SR_RX_FIFO_VALID_DATA ) ) != 0 )
	{
		/* A character is available - place it in the queue of received
		characters.  This might wake a task that was blocked waiting for 
		data. */
		cChar = ( portCHAR )XIo_In32( XPAR_RS232_UART_BASEADDR + XUL_RX_FIFO_OFFSET );
		xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
    }

    if( ( ulISRStatus & XUL_SR_TX_FIFO_EMPTY ) != 0 )
    {
		/* There is space in the FIFO - if there are any characters queue for
		transmission they can be send to the UART now.  This might unblock a
		task that was waiting for space to become available on the Tx queue. */
		if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
		{
			XIo_Out32( XPAR_RS232_UART_BASEADDR + XUL_TX_FIFO_OFFSET, cChar );
		}
    }

	/* If we woke any tasks we may require a context switch. */
	if( xHigherPriorityTaskWoken )
	{
		portYIELD_FROM_ISR();
	}
}