serial.c

FreeRTOS is a portable, open source, mini Real Time Kernel - a free to download and royalty free RTO

/*
	This serial port driver is borrowed heavily from DZComm.  I have
	simplified it by removing a lot of the functionality (hardware 
	flow control, etc.).  For more details and the full version see
	http://dzcomm.sourceforge.net


	FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org 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.

	FreeRTOS.org 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 along 
	with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59 
	Temple Place, Suite 330, Boston, MA  02111-1307  USA.

	A special exception to the GPL is included to allow you to distribute a 
	combined work that includes FreeRTOS.org without being obliged to provide
	the source code for any proprietary components.  See the licensing section
	of http://www.FreeRTOS.org for full details.


	***************************************************************************
	*                                                                         *
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	*                                                                         *
	* This is a concise, step by step, 'hands on' guide that describes both   *
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	*                                                                         *
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	1 tab == 4 spaces!

	Please ensure to read the configuration and relevant port sections of the
	online documentation.

	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.

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	licensing and training services.
*/

/*
Changes from V1.00:
	
	+ Call to the more efficient portSWITCH_CONTEXT() replaces the call to 
	  taskYIELD() in the ISR.

Changes from V1.2.0:

	+ Added vSerialPutString().

Changes from V1.2.3

	+ The function xPortInitMinimal() has been renamed to 
	  xSerialPortInitMinimal() and the function xPortInit() has been renamed
	  to xSerialPortInit().

Changes From V2.0.0

	+ Use portTickType in place of unsigned pdLONG for delay periods.
	+ cQueueReieveFromISR() used in place of xQueueReceive() in ISR.
*/


#include <stdlib.h>
#include <dos.h>
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
#include "semphr.h"
#include "portasm.h"

#define serMAX_IRQs						( 16 )
#define serTRANSMIT_HOLD_EMPTY_INT		( 0x02 )
#define serCOM1_STANDARD_IRQ			( ( unsigned portCHAR ) 4 )
#define serCOM2_STANDARD_IRQ			( ( unsigned portCHAR ) 3 )


#define	serIMR_8259_0					( ( unsigned portCHAR ) 0x21 )
#define	serIMR_8259_1					( ( unsigned portCHAR ) 0xa1 )
#define	serISR_8259_0					( ( unsigned portCHAR ) 0x20 )
#define	serISR_8259_1					( ( unsigned portCHAR ) 0xa0 )
#define	serALL_COMS_INTERRUPTS			( ( unsigned portCHAR ) 0x0f )
#define	serALL_MODEM_CTRL_INTERRUPTS	( ( unsigned portCHAR ) 0x0f )

#define serTRANSMIT_HOLD_OFFSET					( 0 )
#define serRECEIVE_DATA_OFFSET					( 0 )
#define serBAUD_RATE_DIVISOR_LOW_OFFSET			( 0 )
#define serBAUD_RATE_DIVISOR_HIGH_OFFSET		( 1 )
#define serINTERRUPT_ENABLE_OFFSET				( 1 )
#define serINTERRUPT_ID_OFFSET					( 2 )
#define serFIFO_CTRL_OFFSET						( 2 )
#define serLINE_CTRL_OFFSET						( 3 )
#define serMODEM_CTRL_OFFSET					( 4 )
#define serLINE_STATUS_OFFSET					( 5 )
#define serMODEM_STATUS_OFFSET					( 6 )
#define serSCR_OFFSET							( 7 )

#define serMAX_BAUD			( ( unsigned portLONG ) 115200UL )

#define serNO_INTERRUPTS	( 0x00 )

#define vInterruptOn( pxPort, ucInterrupt )										\
{																				\
	unsigned portCHAR ucIn = portINPUT_BYTE( pxPort->usInterruptEnableReg );	\
	if( !( ucIn & ucInterrupt ) )												\
	{																			\
		portOUTPUT_BYTE( pxPort->usInterruptEnableReg, ucIn | ucInterrupt );	\
	}																			\
}																				
/*-----------------------------------------------------------*/

#define vInterruptOff( pxPort, ucInterrupt )									\
{																				\
	unsigned portCHAR ucIn = portINPUT_BYTE( pxPort->usInterruptEnableReg );	\
	if( ucIn & ucInterrupt )													\
	{																			\
		portOUTPUT_BYTE( pxPort->usInterruptEnableReg, ucIn & ~ucInterrupt);	\
	}																			\
}
/*-----------------------------------------------------------*/

typedef enum
{ 
	serCOM1, 
	serCOM2, 
	serCOM3, 
	serCOM4, 
	serCOM5, 
	serCOM6, 
	serCOM7, 
	serCOM8 
} eCOMPort;

typedef enum 
{ 
	serNO_PARITY, 
	serODD_PARITY, 
	serEVEN_PARITY, 
	serMARK_PARITY, 
	serSPACE_PARITY 
} eParity;

typedef enum 
{ 
	serSTOP_1, 
	serSTOP_2 
} eStopBits;

typedef enum 
{ 
	serBITS_5, 
	serBITS_6, 
	serBITS_7, 
	serBITS_8 
} eDataBits;

typedef enum 
{ 
	ser50,		
	ser75,		
	ser110,		
	ser134,		
	ser150,    
	ser200,
	ser300,		
	ser600,		
	ser1200,	
	ser1800,	
	ser2400,   
	ser4800,
	ser9600,		
	ser19200,	
	ser38400,	
	ser57600,	
	ser115200
} eBaud;

/* This *MUST* match the order in the eBaud definition. */
unsigned portLONG ulBaudFromEnum[] = 
{ 
	( unsigned portLONG ) 50, 
	( unsigned portLONG ) 75, 
	( unsigned portLONG ) 110, 
	( unsigned portLONG ) 134, 
	( unsigned portLONG ) 150,	
	( unsigned portLONG ) 200, 
	( unsigned portLONG ) 300, 
	( unsigned portLONG ) 600, 
	( unsigned portLONG ) 1200, 
	( unsigned portLONG ) 1800, 
	( unsigned portLONG ) 2400,   
	( unsigned portLONG ) 4800,   
	( unsigned portLONG ) 9600,  
	( unsigned portLONG ) 19200,  
	( unsigned portLONG ) 38400UL,
	( unsigned portLONG ) 57600UL,
	( unsigned portLONG ) 115200UL
};

typedef struct xCOM_PORT
{ 
	unsigned portSHORT sPort;   /* comm port address eg. 0x3f8    */
	unsigned portCHAR ucIRQ;    /* comm IRQ eg. 3                 */

	/* Next two fields used for setting up the IRQ routine and
	* (un)masking the interrupt in certain circumstances.
	*/
	unsigned portSHORT usIRQVector;
	unsigned portCHAR ucInterruptEnableMast;

	/* Read/Write buffers. */
	xQueueHandle xRxedChars; 
	xQueueHandle xCharsForTx;

	/* This lot are set up to minimise CPU time where accessing the comm
	* port's registers.
	*/
	unsigned portSHORT usTransmitHoldReg; 
	unsigned portSHORT usReceiveDataRegister;
	unsigned portSHORT usBaudRateDivisorLow; 
	unsigned portSHORT usBaudRateDivisorHigh;
	unsigned portSHORT usInterruptEnableReg;
	unsigned portSHORT usInterruptIDReg;
	unsigned portSHORT usFIFOCtrlReg;
	unsigned portSHORT usLineCtrlReg;
	unsigned portSHORT usModemCtrlReg;
	unsigned portSHORT usLineStatusReg;
	unsigned portSHORT usModemStatusReg;
	unsigned portSHORT usSCRReg;
	unsigned portSHORT us8259InterruptServiceReg;
	unsigned portSHORT us8259InterruptMaskReg;

	/* This semaphore does nothing useful except test a feature of the
	scheduler. */
	xSemaphoreHandle xTestSem;

} xComPort;

typedef xComPort *xComPortHandle;

/* A xComPort structure can be associated with each IRQ.  Initially none
are create/installed. */
xComPort *xPortStatus[ serMAX_IRQs ] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL };

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

/* These prototypes are repeated here so we don't have to include the serial header.  This allows
the xComPortHandle structure details to be private to this file. */
xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength );
portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, portCHAR *pcRxedChar, portTickType xBlockTime );
portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, portCHAR cOutChar, portTickType xBlockTime );
portBASE_TYPE xSerialWaitForSemaphore( xComPortHandle xPort );

static void prvSetupPortHardware( xComPort *pxPort, eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits );
static portSHORT sComPortISR( const xComPort * const pxPort );

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

/* Define an interrupt handler for each slot in the xPortStatus array. */

#define COM_IRQ_WRAPPER(N)										\
	static void __interrupt COM_IRQ##N##_WRAPPER( void )		\
	{															\
		portDISABLE_INTERRUPTS();								\
		if( sComPortISR( xPortStatus[##N##] ) )					\
		{														\
			portSWITCH_CONTEXT();								\
		}														\
	} 

COM_IRQ_WRAPPER( 0 )
COM_IRQ_WRAPPER( 1 )
COM_IRQ_WRAPPER( 2 )
COM_IRQ_WRAPPER( 3 )
COM_IRQ_WRAPPER( 4 )
COM_IRQ_WRAPPER( 5 )
COM_IRQ_WRAPPER( 6 )
COM_IRQ_WRAPPER( 7 )
COM_IRQ_WRAPPER( 8 )
COM_IRQ_WRAPPER( 9 )
COM_IRQ_WRAPPER( 10 )
COM_IRQ_WRAPPER( 11 )
COM_IRQ_WRAPPER( 12 )
COM_IRQ_WRAPPER( 13 )
COM_IRQ_WRAPPER( 14 )
COM_IRQ_WRAPPER( 15 )

static pxISR xISRs[ serMAX_IRQs ] = 
{
	COM_IRQ0_WRAPPER, 
	COM_IRQ1_WRAPPER, 
	COM_IRQ2_WRAPPER, 
	COM_IRQ3_WRAPPER, 
	COM_IRQ4_WRAPPER, 
	COM_IRQ5_WRAPPER, 
	COM_IRQ6_WRAPPER, 
	COM_IRQ7_WRAPPER, 
	COM_IRQ8_WRAPPER, 
	COM_IRQ9_WRAPPER, 
	COM_IRQ10_WRAPPER, 
	COM_IRQ11_WRAPPER, 
	COM_IRQ12_WRAPPER, 
	COM_IRQ13_WRAPPER, 
	COM_IRQ14_WRAPPER,
	COM_IRQ15_WRAPPER
};

static pxISR xOldISRs[ serMAX_IRQs ] = { NULL };

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


xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength )
{
xComPort *pxPort;

	/* Create a structure to handle this port. */
	pxPort = ( xComPort * ) pvPortMalloc( sizeof( xComPort ) );
	
	if( pxPort != NULL )
	{
		/* Create the queues used by the comtest task. */
		pxPort->xRxedChars = xQueueCreate( uxBufferLength, ( unsigned portBASE_TYPE ) sizeof( portCHAR ) );
		pxPort->xCharsForTx = xQueueCreate( uxBufferLength, ( unsigned portBASE_TYPE ) sizeof( portCHAR ) );

		/* Create the test semaphore.  This does nothing useful except test a feature of the scheduler. */
		vSemaphoreCreateBinary( pxPort->xTestSem );

		prvSetupPortHardware( pxPort, ePort, eWantedBaud, eWantedParity, eWantedDataBits, eWantedStopBits );