/* FreeRTOS V7.0.1 - Copyright (C) 2011 Real Time Engineers Ltd. *************************************************************************** * * * FreeRTOS tutorial books are available in pdf and paperback. * * Complete, revised, and edited pdf reference manuals are also * * available. * * * * Purchasing FreeRTOS documentation will not only help you, by * * ensuring you get running as quickly as possible and with an * * in-depth knowledge of how to use FreeRTOS, it will also help * * the FreeRTOS project to continue with its mission of providing * * professional grade, cross platform, de facto standard solutions * * for microcontrollers - completely free of charge! * * * * >>> See http://www.FreeRTOS.org/Documentation for details. <<< * * * * Thank you for using FreeRTOS, and thank you for your support! * * * *************************************************************************** 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. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License and the FreeRTOS license exception along with FreeRTOS; if not it can be viewed here: http://www.freertos.org/a00114.html and also obtained by writing to Richard Barry, contact details for whom are available on the FreeRTOS WEB site. 1 tab == 4 spaces! 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 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, 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 char 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_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(); } }