Demo/PPC440_Xilinx_Virtex5_GCC/RTOSDemo/serial/serial.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V6.0.3 - Copyright (C) 2010 Real Time Engineers Ltd.

     ***************************************************************************
     *                                                                         *
     * If you are:                                                             *
     *                                                                         *
     *    + New to FreeRTOS,                                                   *
     *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
     *    + Looking for basic training,                                        *
     *    + Wanting to improve your FreeRTOS skills and productivity           *
     *                                                                         *
     * then take a look at the FreeRTOS eBook                                  *
     *                                                                         *
     *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
     *                  http://www.FreeRTOS.org/Documentation                  *
     *                                                                         *
     * A pdf reference manual is also available.  Both are usually delivered   *
     * to your inbox within 20 minutes to two hours when purchased between 8am *
     * and 8pm GMT (although please allow up to 24 hours in case of            *
     * exceptional circumstances).  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 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.
     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();
 	}
 }
	/*
	FreeRTOS V6.0.3 - Copyright (C) 2010 Real Time Engineers Ltd.

	***************************************************************************
	* *
	* If you are: *
	* *
	* + New to FreeRTOS, *
	* + Wanting to learn FreeRTOS or multitasking in general quickly *
	* + Looking for basic training, *
	* + Wanting to improve your FreeRTOS skills and productivity *
	* *
	* then take a look at the FreeRTOS eBook *
	* *
	* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
	* http://www.FreeRTOS.org/Documentation *
	* *
	* A pdf reference manual is also available. Both are usually delivered *
	* to your inbox within 20 minutes to two hours when purchased between 8am *
	* and 8pm GMT (although please allow up to 24 hours in case of *
	* exceptional circumstances). 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 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.
	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();
	}
	}