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

 /*
     FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.

     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

     ***************************************************************************
      *                                                                       *
      *    FreeRTOS provides completely free yet professionally developed,    *
      *    robust, strictly quality controlled, supported, and cross          *
      *    platform software that has become a de facto standard.             *
      *                                                                       *
      *    Help yourself get started quickly and support the FreeRTOS         *
      *    project by purchasing a FreeRTOS tutorial book, reference          *
      *    manual, or both from: http://www.FreeRTOS.org/Documentation        *
      *                                                                       *
      *    Thank you!                                                         *
      *                                                                       *
     ***************************************************************************

     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.  Full license text is available from the following
     link: http://www.freertos.org/a00114.html

     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, books, training, latest versions,
     license and Real Time Engineers Ltd. contact details.

     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool, a DOS
     compatible FAT file system, and our tiny thread aware UDP/IP stack.

     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
     Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS
     licenses offer ticketed support, indemnification and middleware.

     http://www.SafeRTOS.com - High Integrity Systems also provide a safety
     engineered and independently SIL3 certified version for use in safety and
     mission critical applications that require provable dependability.

     1 tab == 4 spaces!
 */

 /*
 	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 V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.

	VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

	***************************************************************************
	* *
	* FreeRTOS provides completely free yet professionally developed, *
	* robust, strictly quality controlled, supported, and cross *
	* platform software that has become a de facto standard. *
	* *
	* Help yourself get started quickly and support the FreeRTOS *
	* project by purchasing a FreeRTOS tutorial book, reference *
	* manual, or both from: http://www.FreeRTOS.org/Documentation *
	* *
	* Thank you! *
	* *
	***************************************************************************

	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. Full license text is available from the following
	link: http://www.freertos.org/a00114.html

	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, books, training, latest versions,
	license and Real Time Engineers Ltd. contact details.

	http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
	including FreeRTOS+Trace - an indispensable productivity tool, a DOS
	compatible FAT file system, and our tiny thread aware UDP/IP stack.

	http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
	Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
	licenses offer ticketed support, indemnification and middleware.

	http://www.SafeRTOS.com - High Integrity Systems also provide a safety
	engineered and independently SIL3 certified version for use in safety and
	mission critical applications that require provable dependability.

	1 tab == 4 spaces!
	*/

	/*
	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;
	}
	/-----------------------------------------------------------/