piolib.c

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#include "pioLib.h"

/* globals */
IMPORT DAADIO daadio;
PIO pio;

/* forward declarations */
void pioISR();

STATUS pioInit (outputEnableMask, msgQId)
	UINT8		outputEnableMask;	/* Mask to set which are output ports */
	MSG_Q_ID	msgQId;
	{
	UINT8 *	pOutputEnablePort;
	UINT8 *	pPort;
	int		port;
	int		lockKey;

	/* If daadioInit() has not been called, fail */
	if (daadio.initialized == FALSE)
		{
		printf ("daadio not initialized\n");
		return (ERROR);
		}

	/* If mutex semaphore has not been created, do it now */
	if (pio.mutexSem == NULL)
		{
		if ((pio.mutexSem = semMCreate (SEM_Q_PRIORITY|SEM_DELETE_SAFE|
									SEM_INVERSION_SAFE)) == NULL)
			return (ERROR);
		}

	/* Initialize <pOutputEnablePort> to point to the output enable register */
	pOutputEnablePort = (UINT8 *)daadio.baseAddr + PIO_OUTPUT_ENABLE_OFFSET;

	/* Set the output enable register to the mask the user passed us */
	*pOutputEnablePort = outputEnableMask;

	/* Reset all output channels */
	for (port=0; port<PIO_MAX_PORTS; port++, outputEnableMask>>=1)
		{
		if (outputEnableMask & 1)
			{
			pPort = (UINT8 *) daadio.baseAddr + PIO_PORT_NUM_TO_OFF (port);
			*pPort = (UINT8)0;
			}
		}

	/* ????????????????????????? */

	pio.initialized = TRUE;

	return (OK);
	}

STATUS pioSet (port, channel, state)
	int port, channel;
	BOOL state;
	{
	UINT8 *pPort;	/* pointer to port register */
	int channelBit;	/* bit which reflect which channel is being set */

	/* Error checking...
	 * Ensure pioInit() routine has been called 
	 * and the port and channel are within range.
	 */
	
	if (pio.initialized == FALSE)
		{
		printf ("pio not initialized\n");
		return (ERROR);
		}

	if (port < 0 || port >= PIO_MAX_PORTS)
		{
		printf ("port number out of range\n");
		return (ERROR);
		}

	if (channel < 0 || channel >= PIO_MAX_CHANNELS_PER_PORT)
		{
		printf ("channel number out of range\n");
		return (ERROR);
		}

	if ((*((UINT8 *)daadio.baseAddr + PIO_OUTPUT_ENABLE_OFFSET) & (1 << port)) 
		== 0)
		{
		printf ("can not set an input port\n");
		return (ERROR);
		}
	
	/* Initialize <pPort> to point to the appropriate port */
	pPort = (UINT8 *) daadio.baseAddr + PIO_PORT_NUM_TO_OFF (port);

	/* Set a bit in <channelBit> which reflects which channel is being set, 
	   i.e. if channel 0, set bit 0; if channel 1, set bit 1; and so on. */
	channelBit = 1 << channel;

	/* Update the port register pointed to by <pPort> to be set or unset
	   based on the value of <state>. Since this is a read/modify/write
	   operation, mutual exclusion needs to be assured. */
	if (semTake (pio.mutexSem, WAIT_FOREVER) == ERROR)
		return (ERROR);
	if (state)
		*pPort |=  channelBit;
	else
		*pPort &= ~channelBit;
	semGive (pio.mutexSem);
	
	return (OK);
	}

int pioGet (port, channel)
	int port, channel;
	{
	UINT8 *pPort;	/* pointer to port register */
	int channelBit;	/* bit which reflects which channel is being tested */
	BOOL state;		/* whether channel is ON or OFF */

	/* Error checking...
	 * Ensure that pioInit() routine has been called 
	 * and the port and channel are within range.
	 */
	
	if (pio.initialized == FALSE)
		{
		printf ("pio not initialized\n");
		return (ERROR);
		}

	if (port < 0 || port >= PIO_MAX_PORTS)
		{
		printf ("port number out of range\n");
		return (ERROR);
		}

	if (channel < 0 || channel >= PIO_MAX_CHANNELS_PER_PORT)
		{
		printf ("channel number out of range\n");
		return (ERROR);
		}
	
	/* Initialize <pPort> to point to the appropriate port */
	pPort = (UINT8 *) daadio.baseAddr + PIO_PORT_NUM_TO_OFF (port);

	/* Set a bit in <channelBit> which reflects which channel is being set, 
	   i.e. if channel 0, set bit 0; if channel 1, set bit 1; and so on. */
	channelBit = 1 << channel;

	/* Set <state> to be ON or OFF depending on the state of the channel */
	state = (*pPort & channelBit) ? ON : OFF;	

	return (state);
	}


void pioPoll (port, msgQId)
	int port;
	MSG_Q_ID msgQId;
	{
	PIO_MSG_Q_DATA 	msgQData;
	UINT8 			currentState;
	UINT8 			lastState = 0;
	UINT8 			changedChannels;
	UINT8 *			pPort;
	UINT8			channelBit;	
	int 			channel;	
	IMPORT int		errno;

	/* Error checking */
	if (pio.initialized == FALSE)
		{
		printf ("pio not initialized\n");
		return;
		}

	/* Fail if not an input port, i.e. if the corresponding bit in the
	   output enable register is on */
	if (*((UINT8 *)daadio.baseAddr + PIO_OUTPUT_ENABLE_OFFSET) & (1 << port))
		{
		printf ("port not an input port\n");
		return;
		}
	
	/* Initialize <pPort> to point to the appropriate port */
	pPort = (UINT8 *) daadio.baseAddr + PIO_PORT_NUM_TO_OFF (port);

	FOREVER
		{
		taskDelay (PIO_POLL_DELAY);

		/* Get the current state of all the channels in the port. */
		currentState = *pPort;

		/* If the state of the channels did not change, loop back. */
		if (currentState == lastState)
			continue;
		
		/* Identify which channels changed state.  By exclusive or'ing
		   the current with the last state, we have, for each channel
		   in the port, the corresponding bit set in <changedChannels>. */
		changedChannels = currentState ^ lastState;

		/* Check each bit in <changedChannels> to see if that channel
		   changed state.  <channel> keeps track of which channel
		   number we are checking. <channelToCheck> just holds a single
		   set bit corresponding with the channel number we are checking
		   for. */
		for (channel=0; channel<PIO_MAX_CHANNELS_PER_PORT; channel++)
			{

			/* Set a bit in <channelBit> which reflects the channel
			   we are checking. I.e., if channel 0, set bit 0; if 
			   channel 1, set bit 1, and so on. */

			channelBit = 1 << channel;

			/* If the <channelBit> bit is not set in <changedChannels>
			   then this <channel> did not change. Loop back and check
			   the next channel. */

			if (changedChannels & channelBit == 0)
				continue;

			/* <channel> changed */
			/* Initialize the message structure and send it. */
			msgQData.port = port;
			msgQData.channel = channel;
			msgQData.state = currentState;
			msgQData.timeStamp = tickGet();	

			if (pioMsgSend (msgQId, &msgQData) == ERROR)
				{
				printf ("Msg Queue fatal error: aborting poll task\n");
				return;
				}
			}

		/* Update the last state with the current state */
		lastState = currentState;
		}
	}

STATUS pioMsgSend (msgQId, pMsgQData)
	MSG_Q_ID 			msgQId;
	PIO_MSG_Q_DATA *	pMsgQData;
	{
	IMPORT int		errno;
	if (msgQSend (msgQId, pMsgQData, sizeof (PIO_MSG_Q_DATA),
						NO_WAIT, MSG_PRI_NORMAL) == ERROR)
		{

		/* If failure was because queue is full, print
		   warning otherwise return error. */

		if (errno == S_objLib_OBJ_UNAVAILABLE)
			printf ("Msg Queue full, dumping data port %d, channel %d, status is %s at clock tick %d\n", 
					pMsgQData->port, pMsgQData->channel, (pMsgQData->state) ? 
					"ON" : "OFF", pMsgQData->timeStamp);
		else
			return (ERROR);
		}
	return (OK);
	}

void pioISR (param)
	int param;
	{

	/* ??????????????????????? */

	}