i2lib.c

linux-2.6.15.6

static void
i2QueueNeeds(i2eBordStrPtr pB, i2ChanStrPtr pCh, int type)
{
	unsigned short queueIndex;
	unsigned long flags;

	// We turn off all the interrupts during this brief process, since the
	// interrupt-level code might want to put things on the queue as well.

	switch (type) {

	case NEED_INLINE:

		WRITE_LOCK_IRQSAVE(&pB->Dbuf_spinlock,flags);
		if ( !(pCh->channelNeeds & NEED_INLINE) )
		{
			pCh->channelNeeds |= NEED_INLINE;
			queueIndex = pB->i2Dbuf_stuff;
			pB->i2Dbuf[queueIndex++] = pCh;
			if (queueIndex >= CH_QUEUE_SIZE)
				queueIndex = 0;
			pB->i2Dbuf_stuff = queueIndex;
		}
		WRITE_UNLOCK_IRQRESTORE(&pB->Dbuf_spinlock,flags); 
		break;

	case NEED_BYPASS:

		WRITE_LOCK_IRQSAVE(&pB->Bbuf_spinlock,flags);
		if ((type & NEED_BYPASS) && !(pCh->channelNeeds & NEED_BYPASS))
		{
			pCh->channelNeeds |= NEED_BYPASS;
			queueIndex = pB->i2Bbuf_stuff;
			pB->i2Bbuf[queueIndex++] = pCh;
			if (queueIndex >= CH_QUEUE_SIZE)
				queueIndex = 0;
			pB->i2Bbuf_stuff = queueIndex;
		} 
		WRITE_UNLOCK_IRQRESTORE(&pB->Bbuf_spinlock,flags); 
		break;

	case NEED_FLOW:

		WRITE_LOCK_IRQSAVE(&pB->Fbuf_spinlock,flags);
		if ((type & NEED_FLOW) && !(pCh->channelNeeds & NEED_FLOW))
		{
			pCh->channelNeeds |= NEED_FLOW;
			queueIndex = pB->i2Fbuf_stuff;
			pB->i2Fbuf[queueIndex++] = pCh;
			if (queueIndex >= CH_QUEUE_SIZE)
				queueIndex = 0;
			pB->i2Fbuf_stuff = queueIndex;
		}
		WRITE_UNLOCK_IRQRESTORE(&pB->Fbuf_spinlock,flags); 
		break;

	case NEED_CREDIT:
		pCh->channelNeeds |= NEED_CREDIT;
		break;
	default:
		printk(KERN_ERR "i2QueueNeeds called with bad type:%x\n",type);
		break;
	}
	return;
}

//******************************************************************************
// Function:   i2QueueCommands(type, pCh, timeout, nCommands, pCs,...)
// Parameters: type - PTYPE_BYPASS or PTYPE_INLINE
//             pointer to the channel structure
//             maximum period to wait
//             number of commands (n)
//             n commands
// Returns:    Number of commands sent, or -1 for error
//
// get board lock before calling
//
// Description:
// Queues up some commands to be sent to a channel. To send possibly several
// bypass or inline commands to the given channel. The timeout parameter
// indicates how many HUNDREDTHS OF SECONDS to wait until there is room:
// 0 = return immediately if no room, -ive  = wait forever, +ive = number of
// 1/100 seconds to wait. Return values:
// -1 Some kind of nasty error: bad channel structure or invalid arguments.
//  0 No room to send all the commands
// (+)   Number of commands sent
//******************************************************************************
static int
i2QueueCommands(int type, i2ChanStrPtr pCh, int timeout, int nCommands,
					 cmdSyntaxPtr pCs0,...)
{
	int totalsize = 0;
	int blocksize;
	int lastended;
	cmdSyntaxPtr *ppCs;
	cmdSyntaxPtr pCs;
	int count;
	int flag;
	i2eBordStrPtr pB;

	unsigned short maxBlock;
	unsigned short maxBuff;
	short bufroom;
	unsigned short stuffIndex;
	unsigned char *pBuf;
	unsigned char *pInsert;
	unsigned char *pDest, *pSource;
	unsigned short channel;
	int cnt;
	unsigned long flags = 0;
	rwlock_t *lock_var_p = NULL;

	// Make sure the channel exists, otherwise do nothing
	if ( !i2Validate ( pCh ) ) {
		return -1;
	}

	ip2trace (CHANN, ITRC_QUEUE, ITRC_ENTER, 0 );

	pB = pCh->pMyBord;

	// Board must also exist, and THE INTERRUPT COMMAND ALREADY SENT
	if (pB->i2eValid != I2E_MAGIC || pB->i2eUsingIrq == IRQ_UNDEFINED) {
		return -2;
	}
	// If the board has gone fatal, return bad, and also hit the trap routine if
	// it exists.
	if (pB->i2eFatal) {
		if ( pB->i2eFatalTrap ) {
			(*(pB)->i2eFatalTrap)(pB);
		}
		return -3;
	}
	// Set up some variables, Which buffers are we using?  How big are they?
	switch(type)
	{
	case PTYPE_INLINE:
		flag = INL;
		maxBlock = MAX_OBUF_BLOCK;
		maxBuff = OBUF_SIZE;
		pBuf = pCh->Obuf;
		break;
	case PTYPE_BYPASS:
		flag = BYP;
		maxBlock = MAX_CBUF_BLOCK;
		maxBuff = CBUF_SIZE;
		pBuf = pCh->Cbuf;
		break;
	default:
		return -4;
	}
	// Determine the total size required for all the commands
	totalsize = blocksize = sizeof(i2CmdHeader);
	lastended = 0;
	ppCs = &pCs0;
	for ( count = nCommands; count; count--, ppCs++)
	{
		pCs = *ppCs;
		cnt = pCs->length;
		// Will a new block be needed for this one? 
		// Two possible reasons: too
		// big or previous command has to be at the end of a packet.
		if ((blocksize + cnt > maxBlock) || lastended) {
			blocksize = sizeof(i2CmdHeader);
			totalsize += sizeof(i2CmdHeader);
		}
		totalsize += cnt;
		blocksize += cnt;

		// If this command had to end a block, then we will make sure to
		// account for it should there be any more blocks.
		lastended = pCs->flags & END;
	}
	for (;;) {
		// Make sure any pending flush commands go out before we add more data.
		if ( !( pCh->flush_flags && i2RetryFlushOutput( pCh ) ) ) {
			// How much room (this time through) ?
			switch(type) {
			case PTYPE_INLINE:
				lock_var_p = &pCh->Obuf_spinlock;
				WRITE_LOCK_IRQSAVE(lock_var_p,flags);
				stuffIndex = pCh->Obuf_stuff;
				bufroom = pCh->Obuf_strip - stuffIndex;
				break;
			case PTYPE_BYPASS:
				lock_var_p = &pCh->Cbuf_spinlock;
				WRITE_LOCK_IRQSAVE(lock_var_p,flags);
				stuffIndex = pCh->Cbuf_stuff;
				bufroom = pCh->Cbuf_strip - stuffIndex;
				break;
			default:
				return -5;
			}
			if (--bufroom < 0) {
				bufroom += maxBuff;
			}

			ip2trace (CHANN, ITRC_QUEUE, 2, 1, bufroom );

			// Check for overflow
			if (totalsize <= bufroom) {
				// Normal Expected path - We still hold LOCK
				break; /* from for()- Enough room: goto proceed */
			}
		}

		ip2trace (CHANN, ITRC_QUEUE, 3, 1, totalsize );

		// Prepare to wait for buffers to empty
		WRITE_UNLOCK_IRQRESTORE(lock_var_p,flags); 
		serviceOutgoingFifo(pB);	// Dump what we got

		if (timeout == 0) {
			return 0;   // Tired of waiting
		}
		if (timeout > 0)
			timeout--;   // So negative values == forever
		
		if (!in_interrupt()) {
			schedule_timeout_interruptible(1);	// short nap
		} else {
			// we cannot sched/sleep in interrrupt silly
			return 0;   
		}
		if (signal_pending(current)) {
			return 0;   // Wake up! Time to die!!!
		}

		ip2trace (CHANN, ITRC_QUEUE, 4, 0 );

	}	// end of for(;;)

	// At this point we have room and the lock - stick them in.
	channel = pCh->infl.hd.i2sChannel;
	pInsert = &pBuf[stuffIndex];     // Pointer to start of packet
	pDest = CMD_OF(pInsert);         // Pointer to start of command

	// When we start counting, the block is the size of the header
	for (blocksize = sizeof(i2CmdHeader), count = nCommands,
			lastended = 0, ppCs = &pCs0;
		count;
		count--, ppCs++)
	{
		pCs = *ppCs;         // Points to command protocol structure

		// If this is a bookmark request command, post the fact that a bookmark
		// request is pending. NOTE THIS TRICK ONLY WORKS BECAUSE CMD_BMARK_REQ
		// has no parameters!  The more general solution would be to reference
		// pCs->cmd[0].
		if (pCs == CMD_BMARK_REQ) {
			pCh->bookMarks++;

			ip2trace (CHANN, ITRC_DRAIN, 30, 1, pCh->bookMarks );

		}
		cnt = pCs->length;

		// If this command would put us over the maximum block size or 
		// if the last command had to be at the end of a block, we end
		// the existing block here and start a new one.
		if ((blocksize + cnt > maxBlock) || lastended) {

			ip2trace (CHANN, ITRC_QUEUE, 5, 0 );

			PTYPE_OF(pInsert) = type;
			CHANNEL_OF(pInsert) = channel;
			// count here does not include the header
			CMD_COUNT_OF(pInsert) = blocksize - sizeof(i2CmdHeader);
			stuffIndex += blocksize;
			if(stuffIndex >= maxBuff) {
				stuffIndex = 0;
				pInsert = pBuf;
			}
			pInsert = &pBuf[stuffIndex];  // Pointer to start of next pkt
			pDest = CMD_OF(pInsert);
			blocksize = sizeof(i2CmdHeader);
		}
		// Now we know there is room for this one in the current block

		blocksize += cnt;       // Total bytes in this command
		pSource = pCs->cmd;     // Copy the command into the buffer
		while (cnt--) {
			*pDest++ = *pSource++;
		}
		// If this command had to end a block, then we will make sure to account
		// for it should there be any more blocks.
		lastended = pCs->flags & END;
	}	// end for
	// Clean up the final block by writing header, etc

	PTYPE_OF(pInsert) = type;
	CHANNEL_OF(pInsert) = channel;
	// count here does not include the header
	CMD_COUNT_OF(pInsert) = blocksize - sizeof(i2CmdHeader);
	stuffIndex += blocksize;
	if(stuffIndex >= maxBuff) {
		stuffIndex = 0;
		pInsert = pBuf;
	}
	// Updates the index, and post the need for service. When adding these to
	// the queue of channels, we turn off the interrupt while doing so,
	// because at interrupt level we might want to push a channel back to the
	// end of the queue.
	switch(type)
	{
	case PTYPE_INLINE:
		pCh->Obuf_stuff = stuffIndex;  // Store buffer pointer
		WRITE_UNLOCK_IRQRESTORE(&pCh->Obuf_spinlock,flags); 

		pB->debugInlineQueued++;
		// Add the channel pointer to list of channels needing service (first
		// come...), if it's not already there.
		i2QueueNeeds(pB, pCh, NEED_INLINE);
		break;

	case PTYPE_BYPASS:
		pCh->Cbuf_stuff = stuffIndex;  // Store buffer pointer
		WRITE_UNLOCK_IRQRESTORE(&pCh->Cbuf_spinlock,flags); 

		pB->debugBypassQueued++;
		// Add the channel pointer to list of channels needing service (first
		// come...), if it's not already there.
		i2QueueNeeds(pB, pCh, NEED_BYPASS);
		break;
	}

	ip2trace (CHANN, ITRC_QUEUE, ITRC_RETURN, 1, nCommands );

	return nCommands; // Good status: number of commands sent
}

//******************************************************************************
// Function:   i2GetStatus(pCh,resetBits)
// Parameters: Pointer to a channel structure
//             Bit map of status bits to clear
// Returns:    Bit map of current status bits
//
// Description:
// Returns the state of data set signals, and whether a break has been received,
// (see i2lib.h for bit-mapped result). resetBits is a bit-map of any status
// bits to be cleared: I2_BRK, I2_PAR, I2_FRA, I2_OVR,... These are cleared
// AFTER the condition is passed. If pCh does not point to a valid channel,
// returns -1 (which would be impossible otherwise.
//******************************************************************************
static int
i2GetStatus(i2ChanStrPtr pCh, int resetBits)
{
	unsigned short status;
	i2eBordStrPtr pB;

	ip2trace (CHANN, ITRC_STATUS, ITRC_ENTER, 2, pCh->dataSetIn, resetBits );

	// Make sure the channel exists, otherwise do nothing */
	if ( !i2Validate ( pCh ) )
		return -1;

	pB = pCh->pMyBord;

	status = pCh->dataSetIn;

	// Clear any specified error bits: but note that only actual error bits can
	// be cleared, regardless of the value passed.
	if (resetBits)
	{
		pCh->dataSetIn &= ~(resetBits & (I2_BRK | I2_PAR | I2_FRA | I2_OVR));
		pCh->dataSetIn &= ~(I2_DDCD | I2_DCTS | I2_DDSR | I2_DRI);
	}

	ip2trace (CHANN, ITRC_STATUS, ITRC_RETURN, 1, pCh->dataSetIn );

	return status;
}

//******************************************************************************
// Function:   i2Input(pChpDest,count)
// Parameters: Pointer to a channel structure
//             Pointer to data buffer
//             Number of bytes to read
// Returns:    Number of bytes read, or -1 for error
//
// Description:
// Strips data from the input buffer and writes it to pDest. If there is a
// collosal blunder, (invalid structure pointers or the like), returns -1.
// Otherwise, returns the number of bytes read.
//******************************************************************************
static int
i2Input(i2ChanStrPtr pCh)
{
	int amountToMove;
	unsigned short stripIndex;
	int count;
	unsigned long flags = 0;

	ip2trace (CHANN, ITRC_INPUT, ITRC_ENTER, 0);

	// Ensure channel structure seems real
	if ( !i2Validate( pCh ) ) {
		count = -1;
		goto i2Input_exit;
	}
	WRITE_LOCK_IRQSAVE(&pCh->Ibuf_spinlock,flags);

	// initialize some accelerators and private copies
	stripIndex = pCh->Ibuf_strip;

	count = pCh->Ibuf_stuff - stripIndex;

	// If buffer is empty or requested data count was 0, (trivial case) return
	// without any further thought.
	if ( count == 0 ) {
		WRITE_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,flags);
		goto i2Input_exit;
	}
	// Adjust for buffer wrap
	if ( count < 0 ) {
		count += IBUF_SIZE;
	}
	// Don't give more than can be taken by the line discipline
	amountToMove = pCh->pTTY->ldisc.receive_room( pCh->pTTY );
	if (count > amountToMove) {
		count = amountToMove;
	}
	// How much could we copy without a wrap?
	amountToMove = IBUF_SIZE - stripIndex;

	if (amountToMove > count) {
		amountToMove = count;
	}
	// Move the first block
	pCh->pTTY->ldisc.receive_buf( pCh->pTTY, 
		 &(pCh->Ibuf[stripIndex]), NULL, amountToMove );
	// If we needed to wrap, do the second data move
	if (count > amountToMove) {
		pCh->pTTY->ldisc.receive_buf( pCh->pTTY, 
		 pCh->Ibuf, NULL, count - amountToMove );
	}
	// Bump and wrap the stripIndex all at once by the amount of data read. This
	// method is good regardless of whether the data was in one or two pieces.