FreeRTOS/Demo/ARM7_AT91FR40008_GCC/serial/serial.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V7.2.0 - Copyright (C) 2012 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!

     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
      *    not run, what could be wrong?                                      *
      *                                                                       *
      *    http://www.FreeRTOS.org/FAQHelp.html                               *
      *                                                                       *
     ***************************************************************************


     http://www.FreeRTOS.org - Documentation, training, latest information,
     license and contact details.

     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool.

     Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
     the code with commercial support, indemnification, and middleware, under
     the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
     provide a safety engineered and independently SIL3 certified version under
     the SafeRTOS brand: http://www.SafeRTOS.com.
 */

 /*
 	BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART0.

 	This file contains all the serial port components that can be compiled to
 	either ARM or THUMB mode.  Components that must be compiled to ARM mode are
 	contained in serialISR.c.
 */

 /* Standard includes. */
 #include <stdlib.h>

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

 /* Demo application includes. */
 #include "serial.h"
 #include "AT91R40008.h"
 #include "usart.h"
 #include "pio.h"
 #include "aic.h"

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

 /* Constants to setup and access the UART. */
 #define portUSART0_AIC_CHANNEL	( ( unsigned long ) 2 )

 #define serINVALID_QUEUE		( ( xQueueHandle ) 0 )
 #define serHANDLE				( ( xComPortHandle ) 1 )
 #define serNO_BLOCK				( ( portTickType ) 0 )

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

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

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

 /*
  * The queues are created in serialISR.c as they are used from the ISR.
  * Obtain references to the queues and THRE Empty flag.
  */
 extern void vSerialISRCreateQueues(  unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx );

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

 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
 {
 unsigned long ulSpeed;
 unsigned long ulCD;
 xComPortHandle xReturn = serHANDLE;
 extern void ( vUART_ISR_Wrapper )( void );

 	/* The queues are used in the serial ISR routine, so are created from
 	serialISR.c (which is always compiled to ARM mode. */
 	vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx );

 	if(
 		( xRxedChars != serINVALID_QUEUE ) &&
 		( xCharsForTx != serINVALID_QUEUE ) &&
 		( ulWantedBaud != ( unsigned long ) 0 )
 	  )
 	{
 		portENTER_CRITICAL();
 		{
 			/* Enable clock to USART0... */
 			AT91C_BASE_PS->PS_PCER = AT91C_PS_US0;

 			/* Disable all USART0 interrupt sources to begin... */
 			AT91C_BASE_US0->US_IDR = 0xFFFFFFFF;

 			/* Reset various status bits (just in case)... */
 			AT91C_BASE_US0->US_CR = US_RSTSTA;

 			AT91C_BASE_PIO->PIO_PDR = TXD0 | RXD0;  /* Enable RXD and TXD pins */
 			AT91C_BASE_US0->US_CR = US_RSTRX | US_RSTTX | US_RXDIS | US_TXDIS;

 			/* Clear Transmit and Receive Counters */
 			AT91C_BASE_US0->US_RCR = 0;
 			AT91C_BASE_US0->US_TCR = 0;

 			/* Input clock to baud rate generator is MCK */
 			ulSpeed = configCPU_CLOCK_HZ * 10;
 			ulSpeed = ulSpeed / 16;
 			ulSpeed = ulSpeed / ulWantedBaud;

 			/* compute the error */
 			ulCD  = ulSpeed / 10;
 			if ((ulSpeed - (ulCD * 10)) >= 5)
 			ulCD++;

 			/* Define the baud rate divisor register */
 			AT91C_BASE_US0->US_BRGR = ulCD;

 			/* Define the USART mode */
 			AT91C_BASE_US0->US_MR = US_CLKS_MCK | US_CHRL_8 | US_PAR_NO | US_NBSTOP_1 | US_CHMODE_NORMAL;

 			/* Write the Timeguard Register */
 			AT91C_BASE_US0->US_TTGR = 0;

 			/* Setup the interrupt for USART0.

 			Store interrupt handler function address in USART0 vector register... */
 			AT91C_BASE_AIC->AIC_SVR[ portUSART0_AIC_CHANNEL ] = (unsigned long)vUART_ISR_Wrapper;

 			/* USART0 interrupt level-sensitive, priority 1... */
 			AT91C_BASE_AIC->AIC_SMR[ portUSART0_AIC_CHANNEL ] = AIC_SRCTYPE_INT_LEVEL_SENSITIVE | 1;

 			/* Clear some pending USART0 interrupts (just in case)... */
 			AT91C_BASE_US0->US_CR = US_RSTSTA;

 			/* Enable USART0 interrupt sources (but not Tx for now)... */
 			AT91C_BASE_US0->US_IER = US_RXRDY;

 			/* Enable USART0 interrupts in the AIC... */
 			AT91C_BASE_AIC->AIC_IECR = ( 1 << portUSART0_AIC_CHANNEL );

 			/* Enable receiver and transmitter... */
 			AT91C_BASE_US0->US_CR = US_RXEN | US_TXEN;
 		}
 		portEXIT_CRITICAL();
 	}
 	else
 	{
 		xReturn = ( xComPortHandle ) 0;
 	}

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

 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
 {
 	/* The port handle is not required as this driver only supports UART0. */
 	( 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;
 	}
 }
 /*-----------------------------------------------------------*/

 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
 {
 signed char *pxNext;

 	/* NOTE: This implementation does not handle the queue being full as no
 	block time is used! */

 	/* The port handle is not required as this driver only supports UART0. */
 	( void ) pxPort;
 	( void ) usStringLength;

 	/* Send each character in the string, one at a time. */
 	pxNext = ( signed char * ) pcString;
 	while( *pxNext )
 	{
 		xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
 		pxNext++;
 	}
 }
 /*-----------------------------------------------------------*/

 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
 {
 	( void ) pxPort;

 	/* Place the character in the queue of characters to be transmitted. */
 	if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
 	{
 		return pdFAIL;
 	}

 	/* Turn on the Tx interrupt so the ISR will remove the character from the
 	queue and send it.   This does not need to be in a critical section as
 	if the interrupt has already removed the character the next interrupt
 	will simply turn off the Tx interrupt again. */
 	AT91C_BASE_US0->US_IER = US_TXRDY;

 	return pdPASS;
 }
 /*-----------------------------------------------------------*/

 void vSerialClose( xComPortHandle xPort )
 {
 	/* Not supported as not required by the demo application. */
 	( void ) xPort;
 }
 /*-----------------------------------------------------------*/
	/*
	FreeRTOS V7.2.0 - Copyright (C) 2012 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!

	***************************************************************************
	* *
	* Having a problem? Start by reading the FAQ "My application does *
	* not run, what could be wrong? *
	* *
	* http://www.FreeRTOS.org/FAQHelp.html *
	* *
	***************************************************************************


	http://www.FreeRTOS.org - Documentation, training, latest information,
	license and contact details.

	http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
	including FreeRTOS+Trace - an indispensable productivity tool.

	Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
	the code with commercial support, indemnification, and middleware, under
	the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
	provide a safety engineered and independently SIL3 certified version under
	the SafeRTOS brand: http://www.SafeRTOS.com.
	*/

	/*
	BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART0.

	This file contains all the serial port components that can be compiled to
	either ARM or THUMB mode. Components that must be compiled to ARM mode are
	contained in serialISR.c.
	*/

	/* Standard includes. */
	#include <stdlib.h>

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

	/* Demo application includes. */
	#include "serial.h"
	#include "AT91R40008.h"
	#include "usart.h"
	#include "pio.h"
	#include "aic.h"

	/-----------------------------------------------------------/

	/* Constants to setup and access the UART. */
	#define portUSART0_AIC_CHANNEL ( ( unsigned long ) 2 )

	#define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
	#define serHANDLE ( ( xComPortHandle ) 1 )
	#define serNO_BLOCK ( ( portTickType ) 0 )

	/-----------------------------------------------------------/

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

	/-----------------------------------------------------------/

	/*
	* The queues are created in serialISR.c as they are used from the ISR.
	* Obtain references to the queues and THRE Empty flag.
	*/
	extern void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle pxRxedChars, xQueueHandle pxCharsForTx );

	/-----------------------------------------------------------/

	xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
	{
	unsigned long ulSpeed;
	unsigned long ulCD;
	xComPortHandle xReturn = serHANDLE;
	extern void ( vUART_ISR_Wrapper )( void );

	/* The queues are used in the serial ISR routine, so are created from
	serialISR.c (which is always compiled to ARM mode. */
	vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx );

	if(
	( xRxedChars != serINVALID_QUEUE ) &&
	( xCharsForTx != serINVALID_QUEUE ) &&
	( ulWantedBaud != ( unsigned long ) 0 )
	)
	{
	portENTER_CRITICAL();
	{
	/* Enable clock to USART0... */
	AT91C_BASE_PS->PS_PCER = AT91C_PS_US0;

	/* Disable all USART0 interrupt sources to begin... */
	AT91C_BASE_US0->US_IDR = 0xFFFFFFFF;

	/* Reset various status bits (just in case)... */
	AT91C_BASE_US0->US_CR = US_RSTSTA;

	AT91C_BASE_PIO->PIO_PDR = TXD0 \| RXD0; /* Enable RXD and TXD pins */
	AT91C_BASE_US0->US_CR = US_RSTRX \| US_RSTTX \| US_RXDIS \| US_TXDIS;

	/* Clear Transmit and Receive Counters */
	AT91C_BASE_US0->US_RCR = 0;
	AT91C_BASE_US0->US_TCR = 0;

	/* Input clock to baud rate generator is MCK */
	ulSpeed = configCPU_CLOCK_HZ * 10;
	ulSpeed = ulSpeed / 16;
	ulSpeed = ulSpeed / ulWantedBaud;

	/* compute the error */
	ulCD = ulSpeed / 10;
	if ((ulSpeed - (ulCD * 10)) >= 5)
	ulCD++;

	/* Define the baud rate divisor register */
	AT91C_BASE_US0->US_BRGR = ulCD;

	/* Define the USART mode */
	AT91C_BASE_US0->US_MR = US_CLKS_MCK \| US_CHRL_8 \| US_PAR_NO \| US_NBSTOP_1 \| US_CHMODE_NORMAL;

	/* Write the Timeguard Register */
	AT91C_BASE_US0->US_TTGR = 0;

	/* Setup the interrupt for USART0.

	Store interrupt handler function address in USART0 vector register... */
	AT91C_BASE_AIC->AIC_SVR[ portUSART0_AIC_CHANNEL ] = (unsigned long)vUART_ISR_Wrapper;

	/* USART0 interrupt level-sensitive, priority 1... */
	AT91C_BASE_AIC->AIC_SMR[ portUSART0_AIC_CHANNEL ] = AIC_SRCTYPE_INT_LEVEL_SENSITIVE \| 1;

	/* Clear some pending USART0 interrupts (just in case)... */
	AT91C_BASE_US0->US_CR = US_RSTSTA;

	/* Enable USART0 interrupt sources (but not Tx for now)... */
	AT91C_BASE_US0->US_IER = US_RXRDY;

	/* Enable USART0 interrupts in the AIC... */
	AT91C_BASE_AIC->AIC_IECR = ( 1 << portUSART0_AIC_CHANNEL );

	/* Enable receiver and transmitter... */
	AT91C_BASE_US0->US_CR = US_RXEN \| US_TXEN;
	}
	portEXIT_CRITICAL();
	}
	else
	{
	xReturn = ( xComPortHandle ) 0;
	}

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

	signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
	{
	/* The port handle is not required as this driver only supports UART0. */
	( 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;
	}
	}
	/-----------------------------------------------------------/

	void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
	{
	signed char *pxNext;

	/* NOTE: This implementation does not handle the queue being full as no
	block time is used! */

	/* The port handle is not required as this driver only supports UART0. */
	( void ) pxPort;
	( void ) usStringLength;

	/* Send each character in the string, one at a time. */
	pxNext = ( signed char * ) pcString;
	while( *pxNext )
	{
	xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
	pxNext++;
	}
	}
	/-----------------------------------------------------------/

	signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
	{
	( void ) pxPort;

	/* Place the character in the queue of characters to be transmitted. */
	if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
	{
	return pdFAIL;
	}

	/* Turn on the Tx interrupt so the ISR will remove the character from the
	queue and send it. This does not need to be in a critical section as
	if the interrupt has already removed the character the next interrupt
	will simply turn off the Tx interrupt again. */
	AT91C_BASE_US0->US_IER = US_TXRDY;

	return pdPASS;
	}
	/-----------------------------------------------------------/

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