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i2lib.c

/*******************************************************************************
*
*   (c) 1999 by Computone Corporation
*
********************************************************************************
*
*
*   PACKAGE:     Linux tty Device Driver for IntelliPort family of multiport
*                serial I/O controllers.
*
*   DESCRIPTION: High-level interface code for the device driver. Uses the
*                Extremely Low Level Interface Support (i2ellis.c). Provides an
*                interface to the standard loadware, to support drivers or
*                application code. (This is included source code, not a separate
*                compilation module.)
*
*******************************************************************************/
//------------------------------------------------------------------------------
// Note on Strategy:
// Once the board has been initialized, it will interrupt us when:
// 1) It has something in the fifo for us to read (incoming data, flow control
// packets, or whatever).
// 2) It has stripped whatever we have sent last time in the FIFO (and
// consequently is ready for more).
//
// Note also that the buffer sizes declared in i2lib.h are VERY SMALL. This
// worsens performance considerably, but is done so that a great many channels
// might use only a little memory.
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// Revision History:
//
// 0.00 -  4/16/91 --- First Draft
// 0.01 -  4/29/91 --- 1st beta release
// 0.02 -  6/14/91 --- Changes to allow small model compilation
// 0.03 -  6/17/91 MAG Break reporting protected from interrupts routines with
//                     in-line asm added for moving data to/from ring buffers,
//                     replacing a variety of methods used previously.
// 0.04 -  6/21/91 MAG Initial flow-control packets not queued until
//                     i2_enable_interrupts time. Former versions would enqueue
//                     them at i2_init_channel time, before we knew how many
//                     channels were supposed to exist!
// 0.05 - 10/12/91 MAG Major changes: works through the ellis.c routines now;
//                     supports new 16-bit protocol and expandable boards.
//      - 10/24/91 MAG Most changes in place and stable.
// 0.06 -  2/20/92 MAG Format of CMD_HOTACK corrected: the command takes no
//                     argument.
// 0.07 -- 3/11/92 MAG Support added to store special packet types at interrupt
//                     level (mostly responses to specific commands.)
// 0.08 -- 3/30/92 MAG Support added for STAT_MODEM packet
// 0.09 -- 6/24/93 MAG i2Link... needed to update number of boards BEFORE
//                     turning on the interrupt.
// 0.10 -- 6/25/93 MAG To avoid gruesome death from a bad board, we sanity check
//                     some incoming.
//
// 1.1  - 12/25/96 AKM Linux version.
//      - 10/09/98 DMC Revised Linux version.
//------------------------------------------------------------------------------

//************
//* Includes *
//************

#include <linux/sched.h>
#include "i2lib.h"


//***********************
//* Function Prototypes *
//***********************
static void i2QueueNeeds(i2eBordStrPtr, i2ChanStrPtr, int);
static i2ChanStrPtr i2DeQueueNeeds(i2eBordStrPtr, int );
static void i2StripFifo(i2eBordStrPtr);
static void i2StuffFifoBypass(i2eBordStrPtr);
static void i2StuffFifoFlow(i2eBordStrPtr);
static void i2StuffFifoInline(i2eBordStrPtr);
static int i2RetryFlushOutput(i2ChanStrPtr);

// Not a documented part of the library routines (careful...) but the Diagnostic
// i2diag.c finds them useful to help the throughput in certain limited
// single-threaded operations.
static void iiSendPendingMail(i2eBordStrPtr);
static void serviceOutgoingFifo(i2eBordStrPtr);

// Functions defined in ip2.c as part of interrupt handling
static void do_input(struct work_struct *);
static void do_status(struct work_struct *);

//***************
//* Debug  Data *
//***************
#ifdef DEBUG_FIFO

unsigned char DBGBuf[0x4000];
unsigned short I = 0;

static void
WriteDBGBuf(char *s, unsigned char *src, unsigned short n ) 
{
      char *p = src;

      // XXX: We need a spin lock here if we ever use this again

      while (*s) {      // copy label
            DBGBuf[I] = *s++;
            I = I++ & 0x3fff;
      }
      while (n--) {     // copy data
            DBGBuf[I] = *p++;
            I = I++ & 0x3fff;
      }
}

static void
fatality(i2eBordStrPtr pB )
{
      int i;

      for (i=0;i<sizeof(DBGBuf);i++) {
            if ((i%16) == 0)
                  printk("\n%4x:",i);
            printk("%02x ",DBGBuf[i]);
      }
      printk("\n");
      for (i=0;i<sizeof(DBGBuf);i++) {
            if ((i%16) == 0)
                  printk("\n%4x:",i);
            if (DBGBuf[i] >= ' ' && DBGBuf[i] <= '~') {
                  printk(" %c ",DBGBuf[i]);
            } else {
                  printk(" . ");
            }
      }
      printk("\n");
      printk("Last index %x\n",I);
}
#endif /* DEBUG_FIFO */

//********
//* Code *
//********

static inline int
i2Validate ( i2ChanStrPtr pCh )
{
      //ip2trace(pCh->port_index, ITRC_VERIFY,ITRC_ENTER,2,pCh->validity,
      //    (CHANNEL_MAGIC | CHANNEL_SUPPORT));
      return ((pCh->validity & (CHANNEL_MAGIC_BITS | CHANNEL_SUPPORT)) 
                    == (CHANNEL_MAGIC | CHANNEL_SUPPORT));
}

static void iiSendPendingMail_t(unsigned long data)
{
      i2eBordStrPtr pB = (i2eBordStrPtr)data;

      iiSendPendingMail(pB);
}

//******************************************************************************
// Function:   iiSendPendingMail(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// If any outgoing mail bits are set and there is outgoing mailbox is empty,
// send the mail and clear the bits.
//******************************************************************************
static void
iiSendPendingMail(i2eBordStrPtr pB)
{
      if (pB->i2eOutMailWaiting && (!pB->i2eWaitingForEmptyFifo) )
      {
            if (iiTrySendMail(pB, pB->i2eOutMailWaiting))
            {
                  /* If we were already waiting for fifo to empty,
                   * or just sent MB_OUT_STUFFED, then we are
                   * still waiting for it to empty, until we should
                   * receive an MB_IN_STRIPPED from the board.
                   */
                  pB->i2eWaitingForEmptyFifo |=
                        (pB->i2eOutMailWaiting & MB_OUT_STUFFED);
                  pB->i2eOutMailWaiting = 0;
                  pB->SendPendingRetry = 0;
            } else {
/*          The only time we hit this area is when "iiTrySendMail" has
            failed.  That only occurs when the outbound mailbox is
            still busy with the last message.  We take a short breather
            to let the board catch up with itself and then try again.
            16 Retries is the limit - then we got a borked board.
                  /\/\|=mhw=|\/\/                     */

                  if( ++pB->SendPendingRetry < 16 ) {
                        setup_timer(&pB->SendPendingTimer,
                              iiSendPendingMail_t, (unsigned long)pB);
                        mod_timer(&pB->SendPendingTimer, jiffies + 1);
                  } else {
                        printk( KERN_ERR "IP2: iiSendPendingMail unable to queue outbound mail\n" );
                  }
            }
      }
}

//******************************************************************************
// Function:   i2InitChannels(pB, nChannels, pCh)
// Parameters: Pointer to Ellis Board structure
//             Number of channels to initialize
//             Pointer to first element in an array of channel structures
// Returns:    Success or failure
//
// Description:
//
// This function patches pointers, back-pointers, and initializes all the
// elements in the channel structure array.
//
// This should be run after the board structure is initialized, through having
// loaded the standard loadware (otherwise it complains).
//
// In any case, it must be done before any serious work begins initializing the
// irq's or sending commands...
//
//******************************************************************************
static int
i2InitChannels ( i2eBordStrPtr pB, int nChannels, i2ChanStrPtr pCh)
{
      int index, stuffIndex;
      i2ChanStrPtr *ppCh;
      
      if (pB->i2eValid != I2E_MAGIC) {
            COMPLETE(pB, I2EE_BADMAGIC);
      }
      if (pB->i2eState != II_STATE_STDLOADED) {
            COMPLETE(pB, I2EE_BADSTATE);
      }

      LOCK_INIT(&pB->read_fifo_spinlock);
      LOCK_INIT(&pB->write_fifo_spinlock);
      LOCK_INIT(&pB->Dbuf_spinlock);
      LOCK_INIT(&pB->Bbuf_spinlock);
      LOCK_INIT(&pB->Fbuf_spinlock);
      
      // NO LOCK needed yet - this is init

      pB->i2eChannelPtr = pCh;
      pB->i2eChannelCnt = nChannels;

      pB->i2Fbuf_strip = pB->i2Fbuf_stuff = 0;
      pB->i2Dbuf_strip = pB->i2Dbuf_stuff = 0;
      pB->i2Bbuf_strip = pB->i2Bbuf_stuff = 0;

      pB->SendPendingRetry = 0;

      memset ( pCh, 0, sizeof (i2ChanStr) * nChannels );

      for (index = stuffIndex = 0, ppCh = (i2ChanStrPtr *)(pB->i2Fbuf);
              nChannels && index < ABS_MOST_PORTS;
              index++)
      {
            if ( !(pB->i2eChannelMap[index >> 4] & (1 << (index & 0xf)) ) ) {
                  continue;
            }
            LOCK_INIT(&pCh->Ibuf_spinlock);
            LOCK_INIT(&pCh->Obuf_spinlock);
            LOCK_INIT(&pCh->Cbuf_spinlock);
            LOCK_INIT(&pCh->Pbuf_spinlock);
            // NO LOCK needed yet - this is init
            // Set up validity flag according to support level
            if (pB->i2eGoodMap[index >> 4] & (1 << (index & 0xf)) ) {
                  pCh->validity = CHANNEL_MAGIC | CHANNEL_SUPPORT;
            } else {
                  pCh->validity = CHANNEL_MAGIC;
            }
            pCh->pMyBord = pB;      /* Back-pointer */

            // Prepare an outgoing flow-control packet to send as soon as the chance
            // occurs.
            if ( pCh->validity & CHANNEL_SUPPORT ) {
                  pCh->infl.hd.i2sChannel = index;
                  pCh->infl.hd.i2sCount = 5;
                  pCh->infl.hd.i2sType = PTYPE_BYPASS;
                  pCh->infl.fcmd = 37;
                  pCh->infl.asof = 0;
                  pCh->infl.room = IBUF_SIZE - 1;

                  pCh->whenSendFlow = (IBUF_SIZE/5)*4; // when 80% full

            // The following is similar to calling i2QueueNeeds, except that this
            // is done in longhand, since we are setting up initial conditions on
            // many channels at once.
                  pCh->channelNeeds = NEED_FLOW;  // Since starting from scratch
                  pCh->sinceLastFlow = 0;         // No bytes received since last flow
                                                                  // control packet was queued
                  stuffIndex++;
                  *ppCh++ = pCh;      // List this channel as needing
                                                // initial flow control packet sent
            }

            // Don't allow anything to be sent until the status packets come in from
            // the board.

            pCh->outfl.asof = 0;
            pCh->outfl.room = 0;

            // Initialize all the ring buffers

            pCh->Ibuf_stuff = pCh->Ibuf_strip = 0;
            pCh->Obuf_stuff = pCh->Obuf_strip = 0;
            pCh->Cbuf_stuff = pCh->Cbuf_strip = 0;

            memset( &pCh->icount, 0, sizeof (struct async_icount) );
            pCh->hotKeyIn       = HOT_CLEAR;
            pCh->channelOptions = 0;
            pCh->bookMarks      = 0;
            init_waitqueue_head(&pCh->pBookmarkWait);

            init_waitqueue_head(&pCh->open_wait);
            init_waitqueue_head(&pCh->close_wait);
            init_waitqueue_head(&pCh->delta_msr_wait);

            // Set base and divisor so default custom rate is 9600
            pCh->BaudBase    = 921600;    // MAX for ST654, changed after we get
            pCh->BaudDivisor = 96;        // the boxids (UART types) later

            pCh->dataSetIn   = 0;
            pCh->dataSetOut  = 0;

            pCh->wopen       = 0;
            pCh->throttled   = 0;

            pCh->speed       = CBR_9600;

            pCh->flags    = 0;

            pCh->ClosingDelay     = 5*HZ/10;
            pCh->ClosingWaitTime  = 30*HZ;

            // Initialize task queue objects
            INIT_WORK(&pCh->tqueue_input, do_input);
            INIT_WORK(&pCh->tqueue_status, do_status);

#ifdef IP2DEBUG_TRACE
            pCh->trace = ip2trace;
#endif

            ++pCh;
      --nChannels;
      }
      // No need to check for wrap here; this is initialization.
      pB->i2Fbuf_stuff = stuffIndex;
      COMPLETE(pB, I2EE_GOOD);

}

//******************************************************************************
// Function:   i2DeQueueNeeds(pB, type)
// Parameters: Pointer to a board structure
//             type bit map: may include NEED_INLINE, NEED_BYPASS, or NEED_FLOW
// Returns:   
//             Pointer to a channel structure
//
// Description: Returns pointer struct of next channel that needs service of
//  the type specified. Otherwise returns a NULL reference.
//
//******************************************************************************
static i2ChanStrPtr 
i2DeQueueNeeds(i2eBordStrPtr pB, int type)
{
      unsigned short queueIndex;
      unsigned long flags;

      i2ChanStrPtr pCh = NULL;

      switch(type) {

      case  NEED_INLINE:

            WRITE_LOCK_IRQSAVE(&pB->Dbuf_spinlock,flags);
            if ( pB->i2Dbuf_stuff != pB->i2Dbuf_strip)
            {
                  queueIndex = pB->i2Dbuf_strip;
                  pCh = pB->i2Dbuf[queueIndex];
                  queueIndex++;
                  if (queueIndex >= CH_QUEUE_SIZE) {
                        queueIndex = 0;
                  }
                  pB->i2Dbuf_strip = queueIndex;
                  pCh->channelNeeds &= ~NEED_INLINE;
            }
            WRITE_UNLOCK_IRQRESTORE(&pB->Dbuf_spinlock,flags); 
            break;

      case NEED_BYPASS:

            WRITE_LOCK_IRQSAVE(&pB->Bbuf_spinlock,flags);
            if (pB->i2Bbuf_stuff != pB->i2Bbuf_strip)
            {
                  queueIndex = pB->i2Bbuf_strip;
                  pCh = pB->i2Bbuf[queueIndex];
                  queueIndex++;
                  if (queueIndex >= CH_QUEUE_SIZE) {
                        queueIndex = 0;
                  }
                  pB->i2Bbuf_strip = queueIndex;
                  pCh->channelNeeds &= ~NEED_BYPASS;
            }
            WRITE_UNLOCK_IRQRESTORE(&pB->Bbuf_spinlock,flags); 
            break;
      
      case NEED_FLOW:

            WRITE_LOCK_IRQSAVE(&pB->Fbuf_spinlock,flags);
            if (pB->i2Fbuf_stuff != pB->i2Fbuf_strip)
            {
                  queueIndex = pB->i2Fbuf_strip;
                  pCh = pB->i2Fbuf[queueIndex];
                  queueIndex++;
                  if (queueIndex >= CH_QUEUE_SIZE) {
                        queueIndex = 0;
                  }
                  pB->i2Fbuf_strip = queueIndex;
                  pCh->channelNeeds &= ~NEED_FLOW;
            }
            WRITE_UNLOCK_IRQRESTORE(&pB->Fbuf_spinlock,flags); 
            break;
      default:
            printk(KERN_ERR "i2DeQueueNeeds called with bad type:%x\n",type);
            break;
      }
      return pCh;
}

//******************************************************************************
// Function:   i2QueueNeeds(pB, pCh, type)
// Parameters: Pointer to a board structure
//             Pointer to a channel structure
//             type bit map: may include NEED_INLINE, NEED_BYPASS, or NEED_FLOW
// Returns:    Nothing
//
// Description:
// For each type of need selected, if the given channel is not already in the
// queue, adds it, and sets the flag indicating it is in the queue.
//******************************************************************************
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->receive_room;
      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.
      stripIndex += count;
      if (stripIndex >= IBUF_SIZE) {
            stripIndex -= IBUF_SIZE;
      }
      pCh->Ibuf_strip = stripIndex;

      // Update our flow control information and possibly queue ourselves to send
      // it, depending on how much data has been stripped since the last time a
      // packet was sent.
      pCh->infl.asof += count;

      if ((pCh->sinceLastFlow += count) >= pCh->whenSendFlow) {
            pCh->sinceLastFlow -= pCh->whenSendFlow;
            WRITE_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,flags);
            i2QueueNeeds(pCh->pMyBord, pCh, NEED_FLOW);
      } else {
            WRITE_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,flags);
      }

i2Input_exit:

      ip2trace (CHANN, ITRC_INPUT, ITRC_RETURN, 1, count);

      return count;
}

//******************************************************************************
// Function:   i2InputFlush(pCh)
// Parameters: Pointer to a channel structure
// Returns:    Number of bytes stripped, or -1 for error
//
// Description:
// Strips any data from the input buffer. If there is a collosal blunder,
// (invalid structure pointers or the like), returns -1. Otherwise, returns the
// number of bytes stripped.
//******************************************************************************
static int
i2InputFlush(i2ChanStrPtr pCh)
{
      int count;
      unsigned long flags;

      // Ensure channel structure seems real
      if ( !i2Validate ( pCh ) )
            return -1;

      ip2trace (CHANN, ITRC_INPUT, 10, 0);

      WRITE_LOCK_IRQSAVE(&pCh->Ibuf_spinlock,flags);
      count = pCh->Ibuf_stuff - pCh->Ibuf_strip;

      // Adjust for buffer wrap
      if (count < 0) {
            count += IBUF_SIZE;
      }

      // Expedient way to zero out the buffer
      pCh->Ibuf_strip = pCh->Ibuf_stuff;


      // Update our flow control information and possibly queue ourselves to send
      // it, depending on how much data has been stripped since the last time a
      // packet was sent.

      pCh->infl.asof += count;

      if ( (pCh->sinceLastFlow += count) >= pCh->whenSendFlow )
      {
            pCh->sinceLastFlow -= pCh->whenSendFlow;
            WRITE_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,flags);
            i2QueueNeeds(pCh->pMyBord, pCh, NEED_FLOW);
      } else {
            WRITE_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,flags);
      }

      ip2trace (CHANN, ITRC_INPUT, 19, 1, count);

      return count;
}

//******************************************************************************
// Function:   i2InputAvailable(pCh)
// Parameters: Pointer to a channel structure
// Returns:    Number of bytes available, or -1 for error
//
// Description:
// If there is a collosal blunder, (invalid structure pointers or the like),
// returns -1. Otherwise, returns the number of bytes stripped. Otherwise,
// returns the number of bytes available in the buffer.
//******************************************************************************
#if 0
static int
i2InputAvailable(i2ChanStrPtr pCh)
{
      int count;

      // Ensure channel structure seems real
      if ( !i2Validate ( pCh ) ) return -1;


      // initialize some accelerators and private copies
      READ_LOCK_IRQSAVE(&pCh->Ibuf_spinlock,flags);
      count = pCh->Ibuf_stuff - pCh->Ibuf_strip;
      READ_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,flags);

      // Adjust for buffer wrap
      if (count < 0)
      {
            count += IBUF_SIZE;
      }

      return count;
}
#endif 

//******************************************************************************
// Function:   i2Output(pCh, pSource, count)
// Parameters: Pointer to channel structure
//             Pointer to source data
//             Number of bytes to send
// Returns:    Number of bytes sent, or -1 for error
//
// Description:
// Queues the data at pSource to be sent as data packets to the board. If there
// is a collosal blunder, (invalid structure pointers or the like), returns -1.
// Otherwise, returns the number of bytes written. What if there is not enough
// room for all the data? If pCh->channelOptions & CO_NBLOCK_WRITE is set, then
// we transfer as many characters as we can now, then return. If this bit is
// clear (default), routine will spin along until all the data is buffered.
// Should this occur, the 1-ms delay routine is called while waiting to avoid
// applications that one cannot break out of.
//******************************************************************************
static int
i2Output(i2ChanStrPtr pCh, const char *pSource, int count)
{
      i2eBordStrPtr pB;
      unsigned char *pInsert;
      int amountToMove;
      int countOriginal = count;
      unsigned short channel;
      unsigned short stuffIndex;
      unsigned long flags;

      int bailout = 10;

      ip2trace (CHANN, ITRC_OUTPUT, ITRC_ENTER, 2, count, 0 );

      // Ensure channel structure seems real
      if ( !i2Validate ( pCh ) ) 
            return -1;

      // initialize some accelerators and private copies
      pB = pCh->pMyBord;
      channel = pCh->infl.hd.i2sChannel;

      // 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 -1;
      }
      // Proceed as though we would do everything
      while ( count > 0 ) {

            // How much room in output buffer is there?
            READ_LOCK_IRQSAVE(&pCh->Obuf_spinlock,flags);
            amountToMove = pCh->Obuf_strip - pCh->Obuf_stuff - 1;
            READ_UNLOCK_IRQRESTORE(&pCh->Obuf_spinlock,flags);
            if (amountToMove < 0) {
                  amountToMove += OBUF_SIZE;
            }
            // Subtract off the headers size and see how much room there is for real
            // data. If this is negative, we will discover later.
            amountToMove -= sizeof (i2DataHeader);

            // Don't move more (now) than can go in a single packet
            if ( amountToMove > (int)(MAX_OBUF_BLOCK - sizeof(i2DataHeader)) ) {
                  amountToMove = MAX_OBUF_BLOCK - sizeof(i2DataHeader);
            }
            // Don't move more than the count we were given
            if (amountToMove > count) {
                  amountToMove = count;
            }
            // Now we know how much we must move: NB because the ring buffers have
            // an overflow area at the end, we needn't worry about wrapping in the
            // middle of a packet.

// Small WINDOW here with no LOCK but I can't call Flush with LOCK
// We would be flushing (or ending flush) anyway

            ip2trace (CHANN, ITRC_OUTPUT, 10, 1, amountToMove );

            if ( !(pCh->flush_flags && i2RetryFlushOutput(pCh) ) 
                        && amountToMove > 0 )
            {
                  WRITE_LOCK_IRQSAVE(&pCh->Obuf_spinlock,flags);
                  stuffIndex = pCh->Obuf_stuff;
      
                  // Had room to move some data: don't know whether the block size,
                  // buffer space, or what was the limiting factor...
                  pInsert = &(pCh->Obuf[stuffIndex]);

                  // Set up the header
                  CHANNEL_OF(pInsert)     = channel;
                  PTYPE_OF(pInsert)       = PTYPE_DATA;
                  TAG_OF(pInsert)         = 0;
                  ID_OF(pInsert)          = ID_ORDINARY_DATA;
                  DATA_COUNT_OF(pInsert)  = amountToMove;

                  // Move the data
                  memcpy( (char*)(DATA_OF(pInsert)), pSource, amountToMove );
                  // Adjust pointers and indices
                  pSource                             += amountToMove;
                  pCh->Obuf_char_count    += amountToMove;
                  stuffIndex                    += amountToMove + sizeof(i2DataHeader);
                  count                               -= amountToMove;

                  if (stuffIndex >= OBUF_SIZE) {
                        stuffIndex = 0;
                  }
                  pCh->Obuf_stuff = stuffIndex;

                  WRITE_UNLOCK_IRQRESTORE(&pCh->Obuf_spinlock,flags);

                  ip2trace (CHANN, ITRC_OUTPUT, 13, 1, stuffIndex );

            } else {

                  // Cannot move data
                  // becuz we need to stuff a flush 
                  // or amount to move is <= 0

                  ip2trace(CHANN, ITRC_OUTPUT, 14, 3,
                        amountToMove,  pB->i2eFifoRemains,
                        pB->i2eWaitingForEmptyFifo );

                  // Put this channel back on queue
                  // this ultimatly gets more data or wakes write output
                  i2QueueNeeds(pB, pCh, NEED_INLINE);

                  if ( pB->i2eWaitingForEmptyFifo ) {

                        ip2trace (CHANN, ITRC_OUTPUT, 16, 0 );

                        // or schedule
                        if (!in_interrupt()) {

                              ip2trace (CHANN, ITRC_OUTPUT, 61, 0 );

                              schedule_timeout_interruptible(2);
                              if (signal_pending(current)) {
                                    break;
                              }
                              continue;
                        } else {

                              ip2trace (CHANN, ITRC_OUTPUT, 62, 0 );

                              // let interrupt in = WAS restore_flags()
                              // We hold no lock nor is irq off anymore???
                              
                              break;
                        }
                        break;   // from while(count)
                  }
                  else if ( pB->i2eFifoRemains < 32 && !pB->i2eTxMailEmpty ( pB ) )
                  {
                        ip2trace (CHANN, ITRC_OUTPUT, 19, 2,
                              pB->i2eFifoRemains,
                              pB->i2eTxMailEmpty );

                        break;   // from while(count)
                  } else if ( pCh->channelNeeds & NEED_CREDIT ) {

                        ip2trace (CHANN, ITRC_OUTPUT, 22, 0 );

                        break;   // from while(count)
                  } else if ( --bailout) {

                        // Try to throw more things (maybe not us) in the fifo if we're
                        // not already waiting for it.
      
                        ip2trace (CHANN, ITRC_OUTPUT, 20, 0 );

                        serviceOutgoingFifo(pB);
                        //break;  CONTINUE;
                  } else {
                        ip2trace (CHANN, ITRC_OUTPUT, 21, 3,
                              pB->i2eFifoRemains,
                              pB->i2eOutMailWaiting,
                              pB->i2eWaitingForEmptyFifo );

                        break;   // from while(count)
                  }
            }
      } // End of while(count)

      i2QueueNeeds(pB, pCh, NEED_INLINE);

      // We drop through either when the count expires, or when there is some
      // count left, but there was a non-blocking write.
      if (countOriginal > count) {

            ip2trace (CHANN, ITRC_OUTPUT, 17, 2, countOriginal, count );

            serviceOutgoingFifo( pB );
      }

      ip2trace (CHANN, ITRC_OUTPUT, ITRC_RETURN, 2, countOriginal, count );

      return countOriginal - count;
}

//******************************************************************************
// Function:   i2FlushOutput(pCh)
// Parameters: Pointer to a channel structure
// Returns:    Nothing
//
// Description:
// Sends bypass command to start flushing (waiting possibly forever until there
// is room), then sends inline command to stop flushing output, (again waiting
// possibly forever).
//******************************************************************************
static inline void
i2FlushOutput(i2ChanStrPtr pCh)
{

      ip2trace (CHANN, ITRC_FLUSH, 1, 1, pCh->flush_flags );

      if (pCh->flush_flags)
            return;

      if ( 1 != i2QueueCommands(PTYPE_BYPASS, pCh, 0, 1, CMD_STARTFL) ) {
            pCh->flush_flags = STARTFL_FLAG;          // Failed - flag for later

            ip2trace (CHANN, ITRC_FLUSH, 2, 0 );

      } else if ( 1 != i2QueueCommands(PTYPE_INLINE, pCh, 0, 1, CMD_STOPFL) ) {
            pCh->flush_flags = STOPFL_FLAG;           // Failed - flag for later

            ip2trace (CHANN, ITRC_FLUSH, 3, 0 );
      }
}

static int 
i2RetryFlushOutput(i2ChanStrPtr pCh)
{
      int old_flags = pCh->flush_flags;

      ip2trace (CHANN, ITRC_FLUSH, 14, 1, old_flags );

      pCh->flush_flags = 0;   // Clear flag so we can avoid recursion
                                                      // and queue the commands

      if ( old_flags & STARTFL_FLAG ) {
            if ( 1 == i2QueueCommands(PTYPE_BYPASS, pCh, 0, 1, CMD_STARTFL) ) {
                  old_flags = STOPFL_FLAG;      //Success - send stop flush
            } else {
                  old_flags = STARTFL_FLAG;     //Failure - Flag for retry later
            }

            ip2trace (CHANN, ITRC_FLUSH, 15, 1, old_flags );

      }
      if ( old_flags & STOPFL_FLAG ) {
            if (1 == i2QueueCommands(PTYPE_INLINE, pCh, 0, 1, CMD_STOPFL)) {
                  old_flags = 0;    // Success - clear flags
            }

            ip2trace (CHANN, ITRC_FLUSH, 16, 1, old_flags );
      }
      pCh->flush_flags = old_flags;

      ip2trace (CHANN, ITRC_FLUSH, 17, 1, old_flags );

      return old_flags;
}

//******************************************************************************
// Function:   i2DrainOutput(pCh,timeout)
// Parameters: Pointer to a channel structure
//             Maximum period to wait
// Returns:    ?
//
// Description:
// Uses the bookmark request command to ask the board to send a bookmark back as
// soon as all the data is completely sent.
//******************************************************************************
static void
i2DrainWakeup(unsigned long d)
{
      i2ChanStrPtr pCh = (i2ChanStrPtr)d;

      ip2trace (CHANN, ITRC_DRAIN, 10, 1, pCh->BookmarkTimer.expires );

      pCh->BookmarkTimer.expires = 0;
      wake_up_interruptible( &pCh->pBookmarkWait );
}

static void
i2DrainOutput(i2ChanStrPtr pCh, int timeout)
{
      wait_queue_t wait;
      i2eBordStrPtr pB;

      ip2trace (CHANN, ITRC_DRAIN, ITRC_ENTER, 1, pCh->BookmarkTimer.expires);

      pB = pCh->pMyBord;
      // 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;
      }
      if ((timeout > 0) && (pCh->BookmarkTimer.expires == 0 )) {
            // One per customer (channel)
            setup_timer(&pCh->BookmarkTimer, i2DrainWakeup,
                        (unsigned long)pCh);

            ip2trace (CHANN, ITRC_DRAIN, 1, 1, pCh->BookmarkTimer.expires );

            mod_timer(&pCh->BookmarkTimer, jiffies + timeout);
      }
      
      i2QueueCommands( PTYPE_INLINE, pCh, -1, 1, CMD_BMARK_REQ );

      init_waitqueue_entry(&wait, current);
      add_wait_queue(&(pCh->pBookmarkWait), &wait);
      set_current_state( TASK_INTERRUPTIBLE );

      serviceOutgoingFifo( pB );
      
      schedule(); // Now we take our interruptible sleep on

      // Clean up the queue
      set_current_state( TASK_RUNNING );
      remove_wait_queue(&(pCh->pBookmarkWait), &wait);

      // if expires == 0 then timer poped, then do not need to del_timer
      if ((timeout > 0) && pCh->BookmarkTimer.expires && 
                           time_before(jiffies, pCh->BookmarkTimer.expires)) {
            del_timer( &(pCh->BookmarkTimer) );
            pCh->BookmarkTimer.expires = 0;

            ip2trace (CHANN, ITRC_DRAIN, 3, 1, pCh->BookmarkTimer.expires );

      }
      ip2trace (CHANN, ITRC_DRAIN, ITRC_RETURN, 1, pCh->BookmarkTimer.expires );
      return;
}

//******************************************************************************
// Function:   i2OutputFree(pCh)
// Parameters: Pointer to a channel structure
// Returns:    Space in output buffer
//
// Description:
// Returns -1 if very gross error. Otherwise returns the amount of bytes still
// free in the output buffer.
//******************************************************************************
static int
i2OutputFree(i2ChanStrPtr pCh)
{
      int amountToMove;
      unsigned long flags;

      // Ensure channel structure seems real
      if ( !i2Validate ( pCh ) ) {
            return -1;
      }
      READ_LOCK_IRQSAVE(&pCh->Obuf_spinlock,flags);
      amountToMove = pCh->Obuf_strip - pCh->Obuf_stuff - 1;
      READ_UNLOCK_IRQRESTORE(&pCh->Obuf_spinlock,flags);

      if (amountToMove < 0) {
            amountToMove += OBUF_SIZE;
      }
      // If this is negative, we will discover later
      amountToMove -= sizeof(i2DataHeader);

      return (amountToMove < 0) ? 0 : amountToMove;
}
static void

ip2_owake( PTTY tp)
{
      i2ChanStrPtr  pCh;

      if (tp == NULL) return;

      pCh = tp->driver_data;

      ip2trace (CHANN, ITRC_SICMD, 10, 2, tp->flags,
                  (1 << TTY_DO_WRITE_WAKEUP) );

      tty_wakeup(tp);
}

static inline void
set_baud_params(i2eBordStrPtr pB) 
{
      int i,j;
      i2ChanStrPtr  *pCh;

      pCh = (i2ChanStrPtr *) pB->i2eChannelPtr;

      for (i = 0; i < ABS_MAX_BOXES; i++) {
            if (pB->channelBtypes.bid_value[i]) {
                  if (BID_HAS_654(pB->channelBtypes.bid_value[i])) {
                        for (j = 0; j < ABS_BIGGEST_BOX; j++) {
                              if (pCh[i*16+j] == NULL)
                                    break;
                              (pCh[i*16+j])->BaudBase    = 921600;      // MAX for ST654
                              (pCh[i*16+j])->BaudDivisor = 96;
                        }
                  } else {    // has cirrus cd1400
                        for (j = 0; j < ABS_BIGGEST_BOX; j++) {
                              if (pCh[i*16+j] == NULL)
                                    break;
                              (pCh[i*16+j])->BaudBase    = 115200;      // MAX for CD1400
                              (pCh[i*16+j])->BaudDivisor = 12;
                        }
                  }
            }
      }
}

//******************************************************************************
// Function:   i2StripFifo(pB)
// Parameters: Pointer to a board structure
// Returns:    ?
//
// Description:
// Strips all the available data from the incoming FIFO, identifies the type of
// packet, and either buffers the data or does what needs to be done.
//
// Note there is no overflow checking here: if the board sends more data than it
// ought to, we will not detect it here, but blindly overflow...
//******************************************************************************

// A buffer for reading in blocks for unknown channels
static unsigned char junkBuffer[IBUF_SIZE];

// A buffer to read in a status packet. Because of the size of the count field
// for these things, the maximum packet size must be less than MAX_CMD_PACK_SIZE
static unsigned char cmdBuffer[MAX_CMD_PACK_SIZE + 4];

// This table changes the bit order from MSR order given by STAT_MODEM packet to
// status bits used in our library.
static char xlatDss[16] = {
0      | 0     | 0      | 0      ,
0      | 0     | 0      | I2_CTS ,
0      | 0     | I2_DSR | 0      ,
0      | 0     | I2_DSR | I2_CTS ,
0      | I2_RI | 0      | 0      ,
0      | I2_RI | 0      | I2_CTS ,
0      | I2_RI | I2_DSR | 0      ,
0      | I2_RI | I2_DSR | I2_CTS ,
I2_DCD | 0     | 0      | 0      ,
I2_DCD | 0     | 0      | I2_CTS ,
I2_DCD | 0     | I2_DSR | 0      ,
I2_DCD | 0     | I2_DSR | I2_CTS ,
I2_DCD | I2_RI | 0      | 0      ,
I2_DCD | I2_RI | 0      | I2_CTS ,
I2_DCD | I2_RI | I2_DSR | 0      ,
I2_DCD | I2_RI | I2_DSR | I2_CTS };

static inline void
i2StripFifo(i2eBordStrPtr pB)
{
      i2ChanStrPtr pCh;
      int channel;
      int count;
      unsigned short stuffIndex;
      int amountToRead;
      unsigned char *pc, *pcLimit;
      unsigned char uc;
      unsigned char dss_change;
      unsigned long bflags,cflags;

//    ip2trace (ITRC_NO_PORT, ITRC_SFIFO, ITRC_ENTER, 0 );

      while (HAS_INPUT(pB)) {
//          ip2trace (ITRC_NO_PORT, ITRC_SFIFO, 2, 0 );

            // Process packet from fifo a one atomic unit
            WRITE_LOCK_IRQSAVE(&pB->read_fifo_spinlock,bflags);
   
            // The first word (or two bytes) will have channel number and type of
            // packet, possibly other information
            pB->i2eLeadoffWord[0] = iiReadWord(pB);

            switch(PTYPE_OF(pB->i2eLeadoffWord))
            {
            case PTYPE_DATA:
                  pB->got_input = 1;

//                ip2trace (ITRC_NO_PORT, ITRC_SFIFO, 3, 0 );

                  channel = CHANNEL_OF(pB->i2eLeadoffWord); /* Store channel */
                  count = iiReadWord(pB);          /* Count is in the next word */

// NEW: Check the count for sanity! Should the hardware fail, our death
// is more pleasant. While an oversize channel is acceptable (just more
// than the driver supports), an over-length count clearly means we are
// sick!
                  if ( ((unsigned int)count) > IBUF_SIZE ) {
                        pB->i2eFatal = 2;
                        WRITE_UNLOCK_IRQRESTORE(&pB->read_fifo_spinlock,bflags);
                        return;     /* Bail out ASAP */
                  }
                  // Channel is illegally big ?
                  if ((channel >= pB->i2eChannelCnt) ||
                        (NULL==(pCh = ((i2ChanStrPtr*)pB->i2eChannelPtr)[channel])))
                  {
                        iiReadBuf(pB, junkBuffer, count);
                        WRITE_UNLOCK_IRQRESTORE(&pB->read_fifo_spinlock,bflags);
                        break;         /* From switch: ready for next packet */
                  }

                  // Channel should be valid, then

                  // If this is a hot-key, merely post its receipt for now. These are
                  // always supposed to be 1-byte packets, so we won't even check the
                  // count. Also we will post an acknowledgement to the board so that
                  // more data can be forthcoming. Note that we are not trying to use
                  // these sequences in this driver, merely to robustly ignore them.
                  if(ID_OF(pB->i2eLeadoffWord) == ID_HOT_KEY)
                  {
                        pCh->hotKeyIn = iiReadWord(pB) & 0xff;
                        WRITE_UNLOCK_IRQRESTORE(&pB->read_fifo_spinlock,bflags);
                        i2QueueCommands(PTYPE_BYPASS, pCh, 0, 1, CMD_HOTACK);
                        break;   /* From the switch: ready for next packet */
                  }

                  // Normal data! We crudely assume there is room for the data in our
                  // buffer because the board wouldn't have exceeded his credit limit.
                  WRITE_LOCK_IRQSAVE(&pCh->Ibuf_spinlock,cflags);
                                                                              // We have 2 locks now
                  stuffIndex = pCh->Ibuf_stuff;
                  amountToRead = IBUF_SIZE - stuffIndex;
                  if (amountToRead > count)
                        amountToRead = count;

                  // stuffIndex would have been already adjusted so there would 
                  // always be room for at least one, and count is always at least
                  // one.

                  iiReadBuf(pB, &(pCh->Ibuf[stuffIndex]), amountToRead);
                  pCh->icount.rx += amountToRead;

                  // Update the stuffIndex by the amount of data moved. Note we could
                  // never ask for more data than would just fit. However, we might
                  // have read in one more byte than we wanted because the read
                  // rounds up to even bytes. If this byte is on the end of the
                  // packet, and is padding, we ignore it. If the byte is part of
                  // the actual data, we need to move it.

                  stuffIndex += amountToRead;

                  if (stuffIndex >= IBUF_SIZE) {
                        if ((amountToRead & 1) && (count > amountToRead)) {
                              pCh->Ibuf[0] = pCh->Ibuf[IBUF_SIZE];
                              amountToRead++;
                              stuffIndex = 1;
                        } else {
                              stuffIndex = 0;
                        }
                  }

                  // If there is anything left over, read it as well
                  if (count > amountToRead) {
                        amountToRead = count - amountToRead;
                        iiReadBuf(pB, &(pCh->Ibuf[stuffIndex]), amountToRead);
                        pCh->icount.rx += amountToRead;
                        stuffIndex += amountToRead;
                  }

                  // Update stuff index
                  pCh->Ibuf_stuff = stuffIndex;
                  WRITE_UNLOCK_IRQRESTORE(&pCh->Ibuf_spinlock,cflags);
                  WRITE_UNLOCK_IRQRESTORE(&pB->read_fifo_spinlock,bflags);

#ifdef USE_IQ
                  schedule_work(&pCh->tqueue_input);
#else
                  do_input(&pCh->tqueue_input);
#endif

                  // Note we do not need to maintain any flow-control credits at this
                  // time:  if we were to increment .asof and decrement .room, there
                  // would be no net effect. Instead, when we strip data, we will
                  // increment .asof and leave .room unchanged.

                  break;   // From switch: ready for next packet

            case PTYPE_STATUS:
                  ip2trace (ITRC_NO_PORT, ITRC_SFIFO, 4, 0 );
      
                  count = CMD_COUNT_OF(pB->i2eLeadoffWord);

                  iiReadBuf(pB, cmdBuffer, count);
                  // We can release early with buffer grab
                  WRITE_UNLOCK_IRQRESTORE(&pB->read_fifo_spinlock,bflags);

                  pc = cmdBuffer;
                  pcLimit = &(cmdBuffer[count]);

                  while (pc < pcLimit) {
                        channel = *pc++;

                        ip2trace (channel, ITRC_SFIFO, 7, 2, channel, *pc );

                        /* check for valid channel */
                        if (channel < pB->i2eChannelCnt
                               && 
                               (pCh = (((i2ChanStrPtr*)pB->i2eChannelPtr)[channel])) != NULL
                              )
                        {
                              dss_change = 0;

                              switch (uc = *pc++)
                              {
                              /* Breaks and modem signals are easy: just update status */
                              case STAT_CTS_UP:
                                    if ( !(pCh->dataSetIn & I2_CTS) )
                                    {
                                          pCh->dataSetIn |= I2_DCTS;
                                          pCh->icount.cts++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn |= I2_CTS;
                                    break;

                              case STAT_CTS_DN:
                                    if ( pCh->dataSetIn & I2_CTS )
                                    {
                                          pCh->dataSetIn |= I2_DCTS;
                                          pCh->icount.cts++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn &= ~I2_CTS;
                                    break;

                              case STAT_DCD_UP:
                                    ip2trace (channel, ITRC_MODEM, 1, 1, pCh->dataSetIn );

                                    if ( !(pCh->dataSetIn & I2_DCD) )
                                    {
                                          ip2trace (CHANN, ITRC_MODEM, 2, 0 );
                                          pCh->dataSetIn |= I2_DDCD;
                                          pCh->icount.dcd++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn |= I2_DCD;

                                    ip2trace (channel, ITRC_MODEM, 3, 1, pCh->dataSetIn );
                                    break;

                              case STAT_DCD_DN:
                                    ip2trace (channel, ITRC_MODEM, 4, 1, pCh->dataSetIn );
                                    if ( pCh->dataSetIn & I2_DCD )
                                    {
                                          ip2trace (channel, ITRC_MODEM, 5, 0 );
                                          pCh->dataSetIn |= I2_DDCD;
                                          pCh->icount.dcd++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn &= ~I2_DCD;

                                    ip2trace (channel, ITRC_MODEM, 6, 1, pCh->dataSetIn );
                                    break;

                              case STAT_DSR_UP:
                                    if ( !(pCh->dataSetIn & I2_DSR) )
                                    {
                                          pCh->dataSetIn |= I2_DDSR;
                                          pCh->icount.dsr++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn |= I2_DSR;
                                    break;

                              case STAT_DSR_DN:
                                    if ( pCh->dataSetIn & I2_DSR )
                                    {
                                          pCh->dataSetIn |= I2_DDSR;
                                          pCh->icount.dsr++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn &= ~I2_DSR;
                                    break;

                              case STAT_RI_UP:
                                    if ( !(pCh->dataSetIn & I2_RI) )
                                    {
                                          pCh->dataSetIn |= I2_DRI;
                                          pCh->icount.rng++;
                                          dss_change = 1;
                                    }
                                    pCh->dataSetIn |= I2_RI ;
                                    break;

                              case STAT_RI_DN:
                                    // to be compat with serial.c
                                    //if ( pCh->dataSetIn & I2_RI )
                                    //{
                                    //    pCh->dataSetIn |= I2_DRI;
                                    //    pCh->icount.rng++; 
                                    //    dss_change = 1;
                                    //}
                                    pCh->dataSetIn &= ~I2_RI ;
                                    break;

                              case STAT_BRK_DET:
                                    pCh->dataSetIn |= I2_BRK;
                                    pCh->icount.brk++;
                                    dss_change = 1;
                                    break;

                              // Bookmarks? one less request we're waiting for
                              case STAT_BMARK:
                                    pCh->bookMarks--;
                                    if (pCh->bookMarks <= 0 ) {
                                          pCh->bookMarks = 0;
                                          wake_up_interruptible( &pCh->pBookmarkWait );

                                    ip2trace (channel, ITRC_DRAIN, 20, 1, pCh->BookmarkTimer.expires );
                                    }
                                    break;

                              // Flow control packets? Update the new credits, and if
                              // someone was waiting for output, queue him up again.
                              case STAT_FLOW:
                                    pCh->outfl.room =
                                          ((flowStatPtr)pc)->room -
                                          (pCh->outfl.asof - ((flowStatPtr)pc)->asof);

                                    ip2trace (channel, ITRC_STFLW, 1, 1, pCh->outfl.room );

                                    if (pCh->channelNeeds & NEED_CREDIT)
                                    {
                                          ip2trace (channel, ITRC_STFLW, 2, 1, pCh->channelNeeds);

                                          pCh->channelNeeds &= ~NEED_CREDIT;
                                          i2QueueNeeds(pB, pCh, NEED_INLINE);
                                          if ( pCh->pTTY )
                                                ip2_owake(pCh->pTTY);
                                    }

                                    ip2trace (channel, ITRC_STFLW, 3, 1, pCh->channelNeeds);

                                    pc += sizeof(flowStat);
                                    break;

                              /* Special packets: */
                              /* Just copy the information into the channel structure */

                              case STAT_STATUS:

                                    pCh->channelStatus = *((debugStatPtr)pc);
                                    pc += sizeof(debugStat);
                                    break;

                              case STAT_TXCNT:

                                    pCh->channelTcount = *((cntStatPtr)pc);
                                    pc += sizeof(cntStat);
                                    break;

                              case STAT_RXCNT:

                                    pCh->channelRcount = *((cntStatPtr)pc);
                                    pc += sizeof(cntStat);
                                    break;

                              case STAT_BOXIDS:
                                    pB->channelBtypes = *((bidStatPtr)pc);
                                    pc += sizeof(bidStat);
                                    set_baud_params(pB);
                                    break;

                              case STAT_HWFAIL:
                                    i2QueueCommands (PTYPE_INLINE, pCh, 0, 1, CMD_HW_TEST);
                                    pCh->channelFail = *((failStatPtr)pc);
                                    pc += sizeof(failStat);
                                    break;

                              /* No explicit match? then
                               * Might be an error packet...
                               */
                              default:
                                    switch (uc & STAT_MOD_ERROR)
                                    {
                                    case STAT_ERROR:
                                          if (uc & STAT_E_PARITY) {
                                                pCh->dataSetIn |= I2_PAR;
                                                pCh->icount.parity++;
                                          }
                                          if (uc & STAT_E_FRAMING){
                                                pCh->dataSetIn |= I2_FRA;
                                                pCh->icount.frame++;
                                          }
                                          if (uc & STAT_E_OVERRUN){
                                                pCh->dataSetIn |= I2_OVR;
                                                pCh->icount.overrun++;
                                          }
                                          break;

                                    case STAT_MODEM:
                                          // the answer to DSS_NOW request (not change)
                                          pCh->dataSetIn = (pCh->dataSetIn
                                                & ~(I2_RI | I2_CTS | I2_DCD | I2_DSR) )
                                                | xlatDss[uc & 0xf];
                                          wake_up_interruptible ( &pCh->dss_now_wait );
                                    default:
                                          break;
                                    }
                              }  /* End of switch on status type */
                              if (dss_change) {
#ifdef USE_IQ
                                    schedule_work(&pCh->tqueue_status);
#else
                                    do_status(&pCh->tqueue_status);
#endif
                              }
                        }
                        else  /* Or else, channel is invalid */
                        {
                              // Even though the channel is invalid, we must test the
                              // status to see how much additional data it has (to be
                              // skipped)
                              switch (*pc++)
                              {
                              case STAT_FLOW:
                                    pc += 4;    /* Skip the data */
                                    break;

                              default:
                                    break;
                              }
                        }
                  }  // End of while (there is still some status packet left)
                  break;

            default: // Neither packet? should be impossible
                  ip2trace (ITRC_NO_PORT, ITRC_SFIFO, 5, 1,
                        PTYPE_OF(pB->i2eLeadoffWord) );

                  break;
            }  // End of switch on type of packets
      }     //while(board HAS_INPUT)

      ip2trace (ITRC_NO_PORT, ITRC_SFIFO, ITRC_RETURN, 0 );

      // Send acknowledgement to the board even if there was no data!
      pB->i2eOutMailWaiting |= MB_IN_STRIPPED;
      return;
}

//******************************************************************************
// Function:   i2Write2Fifo(pB,address,count)
// Parameters: Pointer to a board structure, source address, byte count
// Returns:    bytes written
//
// Description:
//  Writes count bytes to board io address(implied) from source
//  Adjusts count, leaves reserve for next time around bypass cmds
//******************************************************************************
static int
i2Write2Fifo(i2eBordStrPtr pB, unsigned char *source, int count,int reserve)
{
      int rc = 0;
      unsigned long flags;
      WRITE_LOCK_IRQSAVE(&pB->write_fifo_spinlock,flags);
      if (!pB->i2eWaitingForEmptyFifo) {
            if (pB->i2eFifoRemains > (count+reserve)) {
                  pB->i2eFifoRemains -= count;
                  iiWriteBuf(pB, source, count);
                  pB->i2eOutMailWaiting |= MB_OUT_STUFFED;
                  rc =  count;
            }
      }
      WRITE_UNLOCK_IRQRESTORE(&pB->write_fifo_spinlock,flags);
      return rc;
}
//******************************************************************************
// Function:   i2StuffFifoBypass(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// Stuffs as many bypass commands into the fifo as possible. This is simpler
// than stuffing data or inline commands to fifo, since we do not have
// flow-control to deal with.
//******************************************************************************
static inline void
i2StuffFifoBypass(i2eBordStrPtr pB)
{
      i2ChanStrPtr pCh;
      unsigned char *pRemove;
      unsigned short stripIndex;
      unsigned short packetSize;
      unsigned short paddedSize;
      unsigned short notClogged = 1;
      unsigned long flags;

      int bailout = 1000;

      // Continue processing so long as there are entries, or there is room in the
      // fifo. Each entry represents a channel with something to do.
      while ( --bailout && notClogged && 
                  (NULL != (pCh = i2DeQueueNeeds(pB,NEED_BYPASS))))
      {
            WRITE_LOCK_IRQSAVE(&pCh->Cbuf_spinlock,flags);
            stripIndex = pCh->Cbuf_strip;

            // as long as there are packets for this channel...

            while (stripIndex != pCh->Cbuf_stuff) {
                  pRemove = &(pCh->Cbuf[stripIndex]);
                  packetSize = CMD_COUNT_OF(pRemove) + sizeof(i2CmdHeader);
                  paddedSize = ROUNDUP(packetSize);

                  if (paddedSize > 0) {
                        if ( 0 == i2Write2Fifo(pB, pRemove, paddedSize,0)) {
                              notClogged = 0;   /* fifo full */
                              i2QueueNeeds(pB, pCh, NEED_BYPASS); // Put back on queue
                              break;   // Break from the channel
                        } 
                  }
#ifdef DEBUG_FIFO
WriteDBGBuf("BYPS", pRemove, paddedSize);
#endif      /* DEBUG_FIFO */
                  pB->debugBypassCount++;

                  pRemove += packetSize;
                  stripIndex += packetSize;
                  if (stripIndex >= CBUF_SIZE) {
                        stripIndex = 0;
                        pRemove = pCh->Cbuf;
                  }
            }
            // Done with this channel. Move to next, removing this one from 
            // the queue of channels if we cleaned it out (i.e., didn't get clogged.
            pCh->Cbuf_strip = stripIndex;
            WRITE_UNLOCK_IRQRESTORE(&pCh->Cbuf_spinlock,flags);
      }  // Either clogged or finished all the work

#ifdef IP2DEBUG_TRACE
      if ( !bailout ) {
            ip2trace (ITRC_NO_PORT, ITRC_ERROR, 1, 0 );
      }
#endif
}

//******************************************************************************
// Function:   i2StuffFifoFlow(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// Stuffs as many flow control packets into the fifo as possible. This is easier
// even than doing normal bypass commands, because there is always at most one
// packet, already assembled, for each channel.
//******************************************************************************
static inline void
i2StuffFifoFlow(i2eBordStrPtr pB)
{
      i2ChanStrPtr pCh;
      unsigned short paddedSize           = ROUNDUP(sizeof(flowIn));

      ip2trace (ITRC_NO_PORT, ITRC_SFLOW, ITRC_ENTER, 2,
            pB->i2eFifoRemains, paddedSize );

      // Continue processing so long as there are entries, or there is room in the
      // fifo. Each entry represents a channel with something to do.
      while ( (NULL != (pCh = i2DeQueueNeeds(pB,NEED_FLOW)))) {
            pB->debugFlowCount++;

            // NO Chan LOCK needed ???
            if ( 0 == i2Write2Fifo(pB,(unsigned char *)&(pCh->infl),paddedSize,0)) {
                  break;
            }
#ifdef DEBUG_FIFO
            WriteDBGBuf("FLOW",(unsigned char *) &(pCh->infl), paddedSize);
#endif /* DEBUG_FIFO */

      }  // Either clogged or finished all the work

      ip2trace (ITRC_NO_PORT, ITRC_SFLOW, ITRC_RETURN, 0 );
}

//******************************************************************************
// Function:   i2StuffFifoInline(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// Stuffs as much data and inline commands into the fifo as possible. This is
// the most complex fifo-stuffing operation, since there if now the channel
// flow-control issue to deal with.
//******************************************************************************
static inline void
i2StuffFifoInline(i2eBordStrPtr pB)
{
      i2ChanStrPtr pCh;
      unsigned char *pRemove;
      unsigned short stripIndex;
      unsigned short packetSize;
      unsigned short paddedSize;
      unsigned short notClogged = 1;
      unsigned short flowsize;
      unsigned long flags;

      int bailout  = 1000;
      int bailout2;

      ip2trace (ITRC_NO_PORT, ITRC_SICMD, ITRC_ENTER, 3, pB->i2eFifoRemains, 
                  pB->i2Dbuf_strip, pB->i2Dbuf_stuff );

      // Continue processing so long as there are entries, or there is room in the
      // fifo. Each entry represents a channel with something to do.
      while ( --bailout && notClogged && 
                  (NULL != (pCh = i2DeQueueNeeds(pB,NEED_INLINE))) )
      {
            WRITE_LOCK_IRQSAVE(&pCh->Obuf_spinlock,flags);
            stripIndex = pCh->Obuf_strip;

            ip2trace (CHANN, ITRC_SICMD, 3, 2, stripIndex, pCh->Obuf_stuff );

            // as long as there are packets for this channel...
            bailout2 = 1000;
            while ( --bailout2 && stripIndex != pCh->Obuf_stuff) {
                  pRemove = &(pCh->Obuf[stripIndex]);

                  // Must determine whether this be a data or command packet to
                  // calculate correctly the header size and the amount of
                  // flow-control credit this type of packet will use.
                  if (PTYPE_OF(pRemove) == PTYPE_DATA) {
                        flowsize = DATA_COUNT_OF(pRemove);
                        packetSize = flowsize + sizeof(i2DataHeader);
                  } else {
                        flowsize = CMD_COUNT_OF(pRemove);
                        packetSize = flowsize + sizeof(i2CmdHeader);
                  }
                  flowsize = CREDIT_USAGE(flowsize);
                  paddedSize = ROUNDUP(packetSize);

                  ip2trace (CHANN, ITRC_SICMD, 4, 2, pB->i2eFifoRemains, paddedSize );

                  // If we don't have enough credits from the board to send the data,
                  // flag the channel that we are waiting for flow control credit, and
                  // break out. This will clean up this channel and remove us from the
                  // queue of hot things to do.

                        ip2trace (CHANN, ITRC_SICMD, 5, 2, pCh->outfl.room, flowsize );

                  if (pCh->outfl.room <= flowsize)    {
                        // Do Not have the credits to send this packet.
                        i2QueueNeeds(pB, pCh, NEED_CREDIT);
                        notClogged = 0;
                        break;   // So to do next channel
                  }
                  if ( (paddedSize > 0) 
                        && ( 0 == i2Write2Fifo(pB, pRemove, paddedSize, 128))) {
                        // Do Not have room in fifo to send this packet.
                        notClogged = 0;
                        i2QueueNeeds(pB, pCh, NEED_INLINE); 
                        break;   // Break from the channel
                  }
#ifdef DEBUG_FIFO
WriteDBGBuf("DATA", pRemove, paddedSize);
#endif /* DEBUG_FIFO */
                  pB->debugInlineCount++;

                  pCh->icount.tx += flowsize;
                  // Update current credits
                  pCh->outfl.room -= flowsize;
                  pCh->outfl.asof += flowsize;
                  if (PTYPE_OF(pRemove) == PTYPE_DATA) {
                        pCh->Obuf_char_count -= DATA_COUNT_OF(pRemove);
                  }
                  pRemove += packetSize;
                  stripIndex += packetSize;

                  ip2trace (CHANN, ITRC_SICMD, 6, 2, stripIndex, pCh->Obuf_strip);

                  if (stripIndex >= OBUF_SIZE) {
                        stripIndex = 0;
                        pRemove = pCh->Obuf;

                        ip2trace (CHANN, ITRC_SICMD, 7, 1, stripIndex );

                  }
            }     /* while */
            if ( !bailout2 ) {
                  ip2trace (CHANN, ITRC_ERROR, 3, 0 );
            }
            // Done with this channel. Move to next, removing this one from the
            // queue of channels if we cleaned it out (i.e., didn't get clogged.
            pCh->Obuf_strip = stripIndex;
            WRITE_UNLOCK_IRQRESTORE(&pCh->Obuf_spinlock,flags);
            if ( notClogged )
            {

                  ip2trace (CHANN, ITRC_SICMD, 8, 0 );

                  if ( pCh->pTTY ) {
                        ip2_owake(pCh->pTTY);
                  }
            }
      }  // Either clogged or finished all the work

      if ( !bailout ) {
            ip2trace (ITRC_NO_PORT, ITRC_ERROR, 4, 0 );
      }

      ip2trace (ITRC_NO_PORT, ITRC_SICMD, ITRC_RETURN, 1,pB->i2Dbuf_strip);
}

//******************************************************************************
// Function:   serviceOutgoingFifo(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// Helper routine to put data in the outgoing fifo, if we aren't already waiting
// for something to be there. If the fifo has only room for a very little data,
// go head and hit the board with a mailbox hit immediately. Otherwise, it will
// have to happen later in the interrupt processing. Since this routine may be
// called both at interrupt and foreground time, we must turn off interrupts
// during the entire process.
//******************************************************************************
static void
serviceOutgoingFifo(i2eBordStrPtr pB)
{
      // If we aren't currently waiting for the board to empty our fifo, service
      // everything that is pending, in priority order (especially, Bypass before
      // Inline).
      if ( ! pB->i2eWaitingForEmptyFifo )
      {
            i2StuffFifoFlow(pB);
            i2StuffFifoBypass(pB);
            i2StuffFifoInline(pB);

            iiSendPendingMail(pB);
      } 
}

//******************************************************************************
// Function:   i2ServiceBoard(pB)
// Parameters: Pointer to a board structure
// Returns:    Nothing
//
// Description:
// Normally this is called from interrupt level, but there is deliberately
// nothing in here specific to being called from interrupt level. All the
// hardware-specific, interrupt-specific things happen at the outer levels.
//
// For example, a timer interrupt could drive this routine for some sort of
// polled operation. The only requirement is that the programmer deal with any
// atomiticity/concurrency issues that result.
//
// This routine responds to the board's having sent mailbox information to the
// host (which would normally cause an interrupt). This routine reads the
// incoming mailbox. If there is no data in it, this board did not create the
// interrupt and/or has nothing to be done to it. (Except, if we have been
// waiting to write mailbox data to it, we may do so.
//
// Based on the value in the mailbox, we may take various actions.
//
// No checking here of pB validity: after all, it shouldn't have been called by
// the handler unless pB were on the list.
//******************************************************************************
static inline int
i2ServiceBoard ( i2eBordStrPtr pB )
{
      unsigned inmail;
      unsigned long flags;


      /* This should be atomic because of the way we are called... */
      if (NO_MAIL_HERE == ( inmail = pB->i2eStartMail ) ) {
            inmail = iiGetMail(pB);
      }
      pB->i2eStartMail = NO_MAIL_HERE;

      ip2trace (ITRC_NO_PORT, ITRC_INTR, 2, 1, inmail );

      if (inmail != NO_MAIL_HERE) {
            // If the board has gone fatal, nothing to do but hit a bit that will
            // alert foreground tasks to protest!
            if ( inmail & MB_FATAL_ERROR ) {
                  pB->i2eFatal = 1;
                  goto exit_i2ServiceBoard;
            }

            /* Assuming no fatal condition, we proceed to do work */
            if ( inmail & MB_IN_STUFFED ) {
                  pB->i2eFifoInInts++;
                  i2StripFifo(pB);     /* There might be incoming packets */
            }

            if (inmail & MB_OUT_STRIPPED) {
                  pB->i2eFifoOutInts++;
                  WRITE_LOCK_IRQSAVE(&pB->write_fifo_spinlock,flags);
                  pB->i2eFifoRemains = pB->i2eFifoSize;
                  pB->i2eWaitingForEmptyFifo = 0;
                  WRITE_UNLOCK_IRQRESTORE(&pB->write_fifo_spinlock,flags);

                  ip2trace (ITRC_NO_PORT, ITRC_INTR, 30, 1, pB->i2eFifoRemains );

            }
            serviceOutgoingFifo(pB);
      }

      ip2trace (ITRC_NO_PORT, ITRC_INTR, 8, 0 );

exit_i2ServiceBoard:

      return 0;
}

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