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/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/*
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 QueueHandle_t xRxedChars;
static QueueHandle_t 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 long 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 char ) );
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
/* Only initialise the UART if the queues were created correctly. */
if( ( xRxedChars != NULL ) && ( xCharsForTx != NULL ) )
{
XUartLite_Initialize( &xUART, XPAR_RS232_UART_1_DEVICE_ID );
XUartLite_ResetFifos( &xUART );
XUartLite_DisableInterrupt( &xUART );
if( xPortInstallInterruptHandler( XPAR_XPS_INTC_0_RS232_UART_1_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 char *pcRxedChar, TickType_t 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 char cOutChar, TickType_t 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_1_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_1_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 long ulISRStatus;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE, lDidSomething;
char cChar;
/* Just to remove compiler warning. */
( void ) pxUART;
do
{
lDidSomething = pdFALSE;
ulISRStatus = XIo_In32( XPAR_RS232_UART_1_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 = ( char ) XIo_In32( XPAR_RS232_UART_1_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_1_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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