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/*
FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org 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.
FreeRTOS.org 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.org; if not, write to the Free Software Foundation, Inc., 59
Temple Place, Suite 330, Boston, MA 02111-1307 USA.
A special exception to the GPL is included to allow you to distribute a
combined work that includes FreeRTOS.org without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details.
***************************************************************************
* *
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
* *
* This is a concise, step by step, 'hands on' guide that describes both *
* general multitasking concepts and FreeRTOS specifics. It presents and *
* explains numerous examples that are written using the FreeRTOS API. *
* Full source code for all the examples is provided in an accompanying *
* .zip file. *
* *
***************************************************************************
1 tab == 4 spaces!
Please ensure to read the configuration and relevant port sections of the
online documentation.
http://www.FreeRTOS.org - Documentation, latest information, license and
contact details.
http://www.SafeRTOS.com - A version that is certified for use in safety
critical systems.
http://www.OpenRTOS.com - Commercial support, development, porting,
licensing and training services.
*/
/*
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"
/* Library includes. */
#include "xparameters.h"
#include "xuartlite.h"
#include "xuartlite_l.h"
/*-----------------------------------------------------------*/
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;
/* Structure that maintains information on the UART being used. */
static XUartLite xUART;
/*
* Sample UART interrupt handler. Note this is used to demonstrate the kernel
* features and test the port - it is not intended to represent an efficient
* implementation.
*/
static void vSerialISR( XUartLite *pxUART );
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
/* 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. */
( void ) ulWantedBaud;
/* 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 ) );
/* Only initialise the UART if the queues were created correctly. */
if( ( xRxedChars != NULL ) && ( xCharsForTx != NULL ) )
{
XUartLite_Initialize( &xUART, XPAR_RS232_UART_DEVICE_ID );
XUartLite_ResetFifos( &xUART );
XUartLite_DisableInterrupt( &xUART );
if( xPortInstallInterruptHandler( XPAR_XPS_INTC_0_RS232_UART_INTERRUPT_INTR, ( XInterruptHandler )vSerialISR, (void *)&xUART ) == pdPASS )
{
/* xPortInstallInterruptHandler() could fail if
vPortSetupInterruptController() has not been called prior to this
function. */
XUartLite_EnableInterrupt( &xUART );
}
}
/* There is only one port so the handle is not used. */
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;
/* Just to remove compiler warning. */
( void ) pxPort;
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;
}
/*-----------------------------------------------------------*/
static void vSerialISR( XUartLite *pxUART )
{
unsigned portLONG ulISRStatus;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE, lDidSomething;
portCHAR cChar;
/* Just to remove compiler warning. */
( void ) pxUART;
do
{
lDidSomething = pdFALSE;
ulISRStatus = XIo_In32( XPAR_RS232_UART_BASEADDR + XUL_STATUS_REG_OFFSET );
if( ( ulISRStatus & 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 );
lDidSomething = pdTRUE;
}
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 sent 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 );
lDidSomething = pdTRUE;
}
}
} while( lDidSomething == pdTRUE );
/* If we woke any tasks we may require a context switch. */
if( xHigherPriorityTaskWoken )
{
portYIELD_FROM_ISR();
}
}
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