/* Bid for space on the chip and start the TX if bid successful */
      if ( pCS->InMemoryMode )
      {
             csWritePacketPage( pCS, PKTPG_TX_CMD, pCS->TxStartCMD );
             csWritePacketPage( pCS, PKTPG_TX_LENGTH, BYTE_SWAP(pCS->TxLength) );
      }
      else  /* In IO mode */
      {
             SYS_ENET_OUT_WORD( (pCS->IOAddr)+PORT_TX_CMD, pCS->TxStartCMD );
             SYS_ENET_OUT_WORD( (pCS->IOAddr)+PORT_TX_LENGTH, 
                                 BYTE_SWAP(pCS->TxLength));
      }

      /* Read BusStatus register which indicates success of the request */
      BusStatus = csReadPacketPage( pCS, PKTPG_BUS_ST );

      if ( BusStatus & BUS_ST_RDY4TXNOW )
      {
         /* The chip is ready for transmission now */
         /* Copy the frame to the chip to start transmission */
         csCopyTxFrame( pCS, pCS->pTxFrameChain );

         /* Mark TX as in progress */
         pCS->TxInProgress = TRUE;
         /* Transmission now in progress */

		 if ( !pCS->InISR )
		 {
	        /* Re-enable interrupts at the CPU */
	        INT_UNLOCK( State );
		 }

         break;
      }
      else /* Not ready for TX */
      {

         /* If there was an error in the transmit bid */
         if ( BusStatus & BUS_ST_TX_BID_ERR )
         {
            /* Set TX not in progress */
            pMbuf = pCS->pTxFrameChain;
            pCS->pTxFrameChain = NULL;
            pCS->TxInProgress = FALSE;

            if ( !pCS->InISR )
            {
	          /* Re-enable interrupts at the CPU */
	          INT_UNLOCK( State );

               /* Free the bad mbuf chain */      
               netMblkClChainFree (pMbuf);
            }
            else
            {
               /* queue the mbuf chain to be freed at task level */
               csEnqueue( pCS->pTxBuffFreeList, pMbuf );
            }

            /* Update output stats */
            END_ERR_ADD (&pCS->end, MIB2_OUT_ERRS, +1);
            /*   END_ERR_ADD (&pCS->end, MIB2_OUT_UCAST, -1);*/
            /* @kml         The definition of the MIB-II variable ifOutUcastPkts in Interface
               group from RFC 1158 is "The total  number of  packets that higher-level 
               protocols requested be transmitted to a subnetwork-unicast address, 
               INCLUDE those that were discarded or not sent."*/
#ifdef CS_DEBUG_ENABLE
            logMsg("csStartOutput: CS_END_DEVICE %d, Transmit bid error (too big)\n",
                       pCS->unit, 0,0,0,0,0 );
#endif

            /* Loop up to transmit the next chain */

         }
         else /* Not Rdy4Tx and Not Bid Error */
         {


            /* Start the TX on Rdy4Tx interrupt */
            /* TX buff space not available now. */

            /* Mark TX as in progress */
            pCS->TxInProgress = TRUE;

	          /* Re-enable interrupts at the CPU */
	          INT_UNLOCK( State );

			  /* Exit loop */
            break;
         }
      }
   }
}



/*******************************************************************************
*
* csCopyTxFrame -
*
* This routine copies the packet from a chain of mbufs to the chip.  When all
* the data has been copied, then the chip automatically begins transmitting
* the data.
*
* The reason why this "simple" copy routine is so long and complicated is
* because all reads and writes to the chip must be done as 16-bit words.
* If an mbuf has an odd number of bytes, then the last byte must be saved
* and combined with the first byte of the next mbuf.  Also, some processors,
* such as the MIPS do not allow word writes to non-word aligned addresses.
*
*/

LOCAL void csCopyTxFrame( CS_END_DEVICE *pCS, M_BLK_ID pMbufChain )
{
   M_BLK_ID pMbuf;
   FAST USHORT *pFrame;
   FAST USHORT *pBuff;
   FAST USHORT *pBuffLimit;
   IOADDR TxDataPort;
   UCHAR  *pStart;
   USHORT  Length;
   BOOL HaveExtraByte;
   union
   {
      UCHAR  byte[2];
      USHORT word;
   } Straddle;


   /* Initialize frame pointer and data port address */
   pFrame = pCS->pPacketPage;
   pFrame += (PKTPG_TX_FRAME/2);
   TxDataPort = pCS->IOAddr + PORT_RXTX_DATA;

   HaveExtraByte = FALSE;  /* Start out with no extra byte */

   /* Process the chain of mbufs */
   for ( pMbuf=pMbufChain; pMbuf!=NULL; pMbuf=pMbuf->mBlkHdr.mNext )
   {
      /* Setup starting pointer and length */
      pStart = pMbuf->mBlkHdr.mData;
      Length = pMbuf->mBlkHdr.mLen;

#ifdef ALIGMENT_32BIT
      /* if the mbuf payload starts on an odd address boundary */
      if( (UINT32)pStart & 0x01 )
      {
         /* If there is an extra byte left over from the previous mbuf */
         if ( HaveExtraByte )
         {
            /* Add the first byte from this mbuf to make a word */
            Straddle.byte[1] = *pStart;
 
            /* Write the word which straddles the mbufs to the chip */
            if ( pCS->InMemoryMode )
            {
#if CPU_FAMILY == ARM 
               SYS_ENET_OUT_WORD(pFrame++, Straddle.word);
#else
               *pFrame++ = Straddle.word;
#endif
            }
            else
               SYS_ENET_OUT_WORD( TxDataPort, Straddle.word );
 
            /* Adjust starting pointer and length */
            pStart++;
            Length--;

            HaveExtraByte = FALSE;
         }
         else
         {
            while( Length>=2 )
            {
               /* fetch 16 bits, 8 bits at a time */
               Straddle.byte[0] = *(UCHAR *)pStart++;
               Straddle.byte[1] = *(UCHAR *)pStart++;
    
               /* Write the word which straddles the mbufs to the chip */
               if ( pCS->InMemoryMode )
               {
#if CPU_FAMILY == ARM 
               SYS_ENET_OUT_WORD(pFrame++, Straddle.word);
#else
               *pFrame++ = Straddle.word;
#endif
              }
               else
                  SYS_ENET_OUT_WORD( TxDataPort, Straddle.word );
    
               Length -= 2;
            }
         }
      }

#endif
      /* If there is an extra byte left over from the previous mbuf */
      if ( HaveExtraByte )
      {
         /* Add the first byte from this mbuf to make a word */
         Straddle.byte[1] = *pStart;

         /* Write the word which straddles the mbufs to the chip */
         if ( pCS->InMemoryMode )
         {
#if CPU_FAMILY == ARM 
               SYS_ENET_OUT_WORD(pFrame++, Straddle.word);
#else
               *pFrame++ = Straddle.word;
#endif
         }
         else
            SYS_ENET_OUT_WORD( TxDataPort, Straddle.word );
   
         /* Adjust starting pointer and length */
         pStart++;
         Length--;

#ifdef ALIGMENT_32BIT
         while( Length>=2 )
         {
            /* fetch 16 bits, 8 bits at a time */
            Straddle.byte[0] = *(UCHAR *)pStart++;
            Straddle.byte[1] = *(UCHAR *)pStart++;
 
            /* Write the word which straddles the mbufs to the chip */
            if ( pCS->InMemoryMode )
            {
#if CPU_FAMILY == ARM 
               SYS_ENET_OUT_WORD(pFrame++, Straddle.word);
#else
               *pFrame++ = Straddle.word;
#endif
            }
            else
               SYS_ENET_OUT_WORD( TxDataPort, Straddle.word );

            Length -= 2;
         }
#endif
      }

      /* Point pBuff to the correct starting point */
      pBuff = (USHORT *)pStart;

      /* If there are odd bytes remaining in the mbuf */
      if ( Length & 1 )
      {
         HaveExtraByte = TRUE;

         /* Point pBuffLimit to the extra byte */
         pBuffLimit = (USHORT *)(pStart+Length-1);
      }
      else  /* There is an even number of bytes remaining */
      {
         HaveExtraByte = FALSE;

         /* Point pBuffLimit to just beyond the last word */
         pBuffLimit = (USHORT *)(pStart+Length);
      }

      /* Copy the words in the mbuf to the chip */
      if ( pCS->InMemoryMode )
      {
         while ( pBuff < pBuffLimit ) 
         {
#if CPU_FAMILY == ARM 
               SYS_ENET_OUT_WORD(pFrame++, *pBuff++);
#else
                         *pFrame++ = *pBuff++;
#endif
         }
      }
      else
      {
         while ( pBuff < pBuffLimit ) 
               SYS_ENET_OUT_WORD(TxDataPort, *pBuff++);
      }

      /* If there is an extra byte left over in this mbuf */
      if ( HaveExtraByte )
      {
         /* Save the extra byte for later */
         Straddle.byte[0] = *(UCHAR *)pBuff;
      }

   } /* end Process the chain of mbufs */

   /* If there is an extra byte left over from the last mbuf */
   if ( HaveExtraByte )
   {
      /* Add a zero byte to make a word */
      Straddle.byte[1] = 0;

      /* Write the last word to the chip */
      if ( pCS->InMemoryMode )
      {
#if CPU_FAMILY == ARM 
               SYS_ENET_OUT_WORD(pFrame++, Straddle.word);
#else
               *pFrame++ = Straddle.word;
#endif
      }
      else
         SYS_ENET_OUT_WORD( TxDataPort, Straddle.word );
   }
}






/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
 * Receive-related Routines                                                *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */


/*******************************************************************************
*
* csCopyRxFrame -
*
* This routine copies a received frame from the chip to a receive buffer.
*
*/

LOCAL int csCopyRxFrame( CS_END_DEVICE *pCS, char *pRxBuff )
{
   FAST USHORT *pFrame;
   FAST USHORT *pBuff;
   FAST USHORT *pBuffLimit;
   FAST int RxDataPort;
   USHORT RxLength, RxStatus;
   int test_int;

   /* Initialize the frame pointer and data port address */
   pFrame =  pCS->pPacketPage;
   pFrame += (PKTPG_RX_LENGTH/2);
   RxDataPort = pCS->IOAddr + PORT_RXTX_DATA;

   /* Get the length of the received frame */
   if ( pCS->InMemoryMode )
   {
#if CPU_FAMILY == ARM
      RxLength = SYS_ENET_IN_WORD(pFrame++);
#else
      RxLength = *pFrame++;
#endif
      RxLength = BYTE_SWAP( RxLength );
   }
   else  /* In IO mode */
   {
      RxStatus = SYS_ENET_IN_WORD( RxDataPort );  /* Discard RxStatus */
      RxLength = SYS_ENET_IN_WORD( RxDataPort );
      RxLength = BYTE_SWAP( RxLength );
   }


   /* Setup pointers to the buffer for copying */
   pBuff = (USHORT *)pRxBuff;
   test_int = (int) pBuff;
   if ((test_int % 2) != 0)
   {
#ifdef CS_DEBUG_ENABLE
      logMsg("receive buffer not on half word boundary: %x\n", (int)pBuff,0,0,0,0,0);
#endif
   }
   pBuffLimit  = pBuff;
   pBuffLimit += ((RxLength+1)/2);

   /* Copy the frame from the chip to the buffer */
   if ( pCS->InMemoryMode )
   {
      while ( pBuff < pBuffLimit ) 
#if CPU_FAMILY == ARM
         *pBuff++ = SYS_ENET_IN_WORD(pFrame++);
#else
         *pBuff++ = *pFrame++;
#endif
   }
   else
   {
      while ( pBuff < pBuffLimit ) 
         *pBuff++ = SYS_ENET_IN_WORD( RxDataPort );
   }

   return (RxLength);
}


/*******************************************************************************
*
* csProcessReceive -
*
* This routine processes a received packet.  The received packet was copied to
* a receive buffer at interrupt time and this routine processses the receive
* buffer at task time via netTask().
*
* The packet is copied to an mbuf chain.  The mbuf chain is then
* passed up to the protocol stack.
*
*/
LOCAL void csProcessReceive( CS_END_DEVICE *pCS, M_BLK_ID pMBuff )
{

   /* Spl = splnet( );*/
   
        /* Update the MIB2 Static */
    END_ERR_ADD (&pCS->end, MIB2_IN_UCAST, +1);

   /* Pass the mbuf chain up to the protocol stack */
    /* Call the upper layer's receive routine. */
    END_RCV_RTN_CALL(&pCS->end, pMBuff);
   /* splx( Spl ); */
}



/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
 * Misc. Routines