eni_receive.c

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/*
 *
 * ===================================
 * HARP  |  Host ATM Research Platform
 * ===================================
 *
 *
 * This Host ATM Research Platform ("HARP") file (the "Software") is
 * made available by Network Computing Services, Inc. ("NetworkCS")
 * "AS IS".  NetworkCS does not provide maintenance, improvements or
 * support of any kind.
 *
 * NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED,
 * INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE
 * SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE.
 * In no event shall NetworkCS be responsible for any damages, including
 * but not limited to consequential damages, arising from or relating to
 * any use of the Software or related support.
 *
 * Copyright 1994-1998 Network Computing Services, Inc.
 *
 * Copies of this Software may be made, however, the above copyright
 * notice must be reproduced on all copies.
 *
 *	@(#) $Id: eni_receive.c,v 1.3 1998/10/31 20:06:45 phk Exp $
 *
 */

/*
 * Efficient ENI Adapter Support
 * -----------------------------
 *
 * Receive management
 *
 */

#include <netatm/kern_include.h>

#include <dev/hea/eni_stats.h>
#include <dev/hea/eni.h>
#include <dev/hea/eni_var.h>

#ifndef lint
__RCSID("@(#) $Id: eni_receive.c,v 1.3 1998/10/31 20:06:45 phk Exp $");
#endif

static void	eni_recv_stack __P((void *, KBuffer *));

#ifdef	DIAGNOSTIC
extern int	eni_pdu_print;
#endif

/*
 * Procedure to remove VCs from the Service List and generate DMA
 * requests to move the associated PDUs into host memory. As PDUs
 * are completed in adapter memory, the adapter examines the IN_SERVICE
 * bit for the VC in the VC table. If this bit is not set, the adapter
 * will place the VC number at the end of the service list queue, set
 * the IN_SERVICE bit in the VC table, and interrupt the host. The host
 * will remove VCs from the service list, clear the IN_SERVICE bit in
 * the VC table, and create a DMA list to move the PDU into host buffers.
 *
 * Arguments:
 *	eup		pointer to per unit structure
 *
 * Returns:
 *	none
 *
 */
void
eni_do_service ( eup )
	Eni_unit *eup;
{
	int		vcc;
	Eni_vcc		*evp;
	u_long		servwrite;
	VCI_Table	*vct;
	u_long		rdptr;
	u_long		*rxp;
	KBuffer		*m;
	u_long		dma[TEMP_DMA_SIZE];
	u_long		i, j;
	u_long		dma_rd, dma_wr;
	u_long		dma_avail;
	int		pdulen;
	int		mask;
	u_long		*upp;

	/*
	 * Where is the adapter currently inserting entries?
	 */
	servwrite = eup->eu_midway[MIDWAY_SVCWR] & SVC_SIZE_MASK;
	/*
	 * As long as we're not caught up with the adapter, keep
	 * removing VCs from the service list.
	 */
	while ( servwrite != eup->eu_servread ) {
		int	vci_hdr;
		u_long	descr;

		/*
		 * Get VC number and find VC table entry.
		 */
		vcc = eup->eu_svclist[eup->eu_servread];
		vct = &eup->eu_vcitbl[vcc];
		vci_hdr = vct->vci_control;	/* Current status */

		/*
		 * Check that this VCC still needs servicing. We
		 * might have closed this VCC down in between
		 * the adapter setting the flag and our checking
		 * the flag. Also check that we haven't placed the
		 * VCC into TRASH mode.
		 */
		if ( ( vci_hdr & VCI_IN_SERVICE ) == 0 ||
		    ( vci_hdr & ~VCI_MODE_MASK ==
			VCI_MODE_TRASH << VCI_MODE_SHIFT ) )
			    goto next_vcc;

		/*
		 * Find the size of this VCs buffer
		 */
		mask = (vci_hdr >> VCI_SIZE_SHIFT) & VCI_SIZE_MASK;
		mask = 1 << (ENI_LOC_PREDIV + mask);
		/* Turn byte count into word count */
		mask >>= 2;
		/*
		 * Find the start of the adapter buffer for this VC.
		 */
		rxp = (u_long *)
		    ((int)(((vci_hdr >> VCI_LOC_SHIFT ) & VCI_LOC_MASK)
			<< ENI_LOC_PREDIV) + (int)eup->eu_ram);
		/*
		 * Locate incoming VCC for this PDU and find where we
		 * should next read from.
		 */
		evp = (Eni_vcc *) atm_dev_vcc_find ( (Cmn_unit *)eup,
		    0, vcc, VCC_IN );
		if ( evp == (Eni_vcc *)NULL )
			goto next_vcc;		/* VCI no longer active */
		rdptr = evp->ev_rxpos;
		/*
		 * Find out where the adapter is currently reassembling.
		 * The PDU which starts at descr is not yet complete so we
		 * must stop there.
		 */
		descr = ( vct->vci_descr >> 16 ) & 0x7FFF;
		/*
		 * As long as we haven't processed all the completed PDUs on
		 * this VC, keep going...
		 */
		while ( rdptr != descr )
		{
		    int		n_cells;
		    int		pdu_descr;
		    int		aal5;

		    /*
		     * Ensure that the following are reset for every new
		     * PDU.
		     */
		    upp = NULL;
		    m = NULL;

		    /*
		     * Fisrt build a DMA with JK to skip the descriptor word.
		     * We must always skip the descriptor even if it turns out
		     * that there isn't any PDU here.
		     */
		    j = 0;
		    dma[j++] = (((rdptr + 1) & (mask-1)) << DMA_COUNT_SHIFT ) |
		    	( vcc << DMA_VCC_SHIFT ) | DMA_JK;
		    dma[j++] = 0;

		    /*
		     * We'll use some of the values below for skipping
		     * bad PDUs or counting statistics so compute them
		     * now.
		     */

		    /*
		     * Grab a copy of the descriptor word
		     */
		    pdu_descr = rxp[rdptr];

		    /*
		     * Strip out cell count from descriptor word.
		     * At this point, we still don't know if there
		     * is any real data until after we check for
		     * TRASH mode.
		     */
		    n_cells = pdu_descr & DESCR_CELL_COUNT;

		    /*
		     * Is this an AAL5 PDU? Check MODE in vci_hdr.
		     */
		    aal5 = ( ( vci_hdr & ~VCI_MODE_MASK ) ==
			VCI_MODE_AAL5 << VCI_MODE_SHIFT );

		    /*
		     * Now check to see if we're trashing on this vcc.
		     * If so, there is no data with this VC and the
		     * next word after the current descriptor is the
		     * descriptor for the next PDU.
		     */
		    if ( ( pdu_descr & DESCR_TRASH_BIT ) != 0 ) {
			if ( aal5 )
				/*
				 * Count as number of AAL5 cells dropped
				 */
				eup->eu_stats.eni_st_aal5.aal5_drops += n_cells;
			else
				/*
				 * Count as number of AAL0 cells dropped
				 */
				eup->eu_stats.eni_st_aal0.aal0_drops += n_cells;
			eup->eu_pif.pif_ierrors++;
			/*
			 * When cells have been trashed, all we have in the
			 * buffer is a descriptor word. There are no data
			 * words. Set the number of cells to zero so that
			 * we correctly skip to the next word which will
			 * be the descriptor for the next PDU.
			 */
			n_cells = 0;
			/*
			 * Go issue the DMA to skip this descriptor word.
			 */
			goto send_dma;
		    }

		    /*
		     * Data length: number of cells * cell size
		     */
		    pdulen = n_cells * BYTES_PER_CELL;

		    /*
		     * If this is an AAL5 PDU, then we need to check
		     * for the presence of any CRC errors. If there
		     * is one or more CRC errors, then we are going to
		     * drop this PDU.
		     */
		    if ( aal5 && ( pdu_descr & DESCR_CRC_ERR ) ) {
			/*
			 * Count the stat
			 */
			eup->eu_pif.pif_ierrors++;
			eup->eu_stats.eni_st_aal5.aal5_pdu_crc++;
			if ( evp->ev_connvc->cvc_vcc )
				evp->ev_connvc->cvc_vcc->vc_ierrors++;
			/*
			 * Build a DMA entry to skip the rest of this
			 * PDU.
			 */
			dma[j++] =
			    (((rdptr + n_cells*WORDS_PER_CELL + 1)
				& (mask-1)) << DMA_COUNT_SHIFT ) |
				    (vcc << DMA_VCC_SHIFT ) | DMA_JK;
			dma[j++] = 0;
			/*
			 * All done with this PDU. Get a buffer to save some
			 * data for reclamation services.
			 */
			KB_ALLOCPKT ( m, ENI_SMALL_BSIZE, KB_F_NOWAIT,
			    KB_T_DATA );
			if ( m ) {
				u_long	*up;

				KB_DATASTART ( m, up, u_long * );
				/*
				 * Indicate no PDU
				 */
				KB_PLENSET ( m, 0 );
				/*
				 * Set buffer length - only driver overhead
				 */
				KB_LEN ( m ) = 3 * sizeof ( u_long );
				/*
				 * Insert vcc, space for DMA pointers,
				 * and pdulen
				 */
				*up++ = vcc;
				upp = up;	/* Remember location */
				up++;		/* And skip it */
						/* - to be filled later */
				*up = pdulen;	/* Actual PDU length if it */
						/* were valid */
			} else {
				/*
				 * We've a real problem here as now we can't
				 * reclaim/advance resources/safety pointers.
				 */
				eup->eu_stats.eni_st_drv.drv_rv_norsc++;
#ifdef	DO_LOG
				log ( LOG_ERR,
    "eni_do_service: No drain buffers available. Receiver about to lock.\n" );
#endif
			}
			goto send_dma;
		    }

		    /*
		     * Do we need to strip the AAL layer? Yes if this
		     * is an AAL5 PDU.
		     */
		    if ( aal5 ) {
			/*
			 * Grab the CS-PDU length. Find the address of the
			 * last word, back up one word to skip CRC, and
			 * then mask the whole thing to handle circular wraps.
			 */
			pdulen = rxp[(rdptr + n_cells*WORDS_PER_CELL - 1)
			    & (mask-1)]
				& 0xFFFF;
		    }

		    /*
		     * We now have a valid PDU of some length. Build
		     * the necessary DMA list to move it into host
		     * memory.
		     */

		    /*
		     * Get an initial buffer.
		     */
		    KB_ALLOCPKT ( m, ENI_SMALL_BSIZE, KB_F_NOWAIT, KB_T_DATA );
		    /*
		     * Do we have a valid buffer?
		     */
		    if ( m != (KBuffer *)NULL )
		    {
			int	len;
			u_long	*up;
			KBuffer *m0;
	
			KB_DATASTART ( m, up, u_long * );
			/*
			 * Fill in pdulen in PKTHDR structure (for IP).
			 */
			KB_PLENSET ( m, pdulen );
			/*
			 * We're going to save the VCI nuber, the start
			 * and stop DMA pointers, and the PDU length at
			 * the head of the buffer. We'll pull this out
			 * later after the DMA has completed.
			 *
			 * Insert VCI number as first word in first buffer,
			 * remeber where we want to store the start/stop
			 * pointers, and store the PDU length.
			 */
			*up++ = vcc;	/* PDU's VCC */
			upp = up;	/* Remember where we are */
			up++;		/* To stuff start/stop pointers in */
			*up++ = pdulen;	/* PDU's length */
			/*
			 * Leave some extra room in case a higher protocol
			 * (IP) wants to do a pullup. Maybe we can keep
			 * someone from having to allocate another buffer
			 * a do a larger memory copy.
			 */
			len = MIN ( ENI_SMALL_BSIZE, pdulen );
			(void) eni_set_dma ( eup, 1, dma, TEMP_DMA_SIZE, &j,
				vcc, (u_long)up, len );
			/*
			 * Adjust length of remaining data in PDU
			 */
			pdulen -= len;
			/*
			 * Set buffer length, including our overhead
			 */
			KB_LEN ( m ) = len + 3 * sizeof ( u_long );
			/*
			 * Finish by moving anything which won't fit in
			 * first buffer
			 */
			m0 = m;
			while ( pdulen ) {
				KBuffer *m1;
				u_long	data_addr;
	
				/*
				 * Get another buffer
				 */
				KB_ALLOCEXT ( m1, ENI_LARGE_BSIZE, KB_F_NOWAIT,
					KB_T_DATA );
	
				/*
				 * If we succeeded...
				 */
				if ( m1 ) {
				    /*
				     * Figure out how much we can move into
				     * this buffer.
				     */
				    len = MIN ( ENI_LARGE_BSIZE, pdulen );
				    /*
				     * Setup DMA list for this buffer
				     */
				    KB_DATASTART ( m1, data_addr, u_long );
				    (void) eni_set_dma
					( eup, 1, dma, TEMP_DMA_SIZE, &j, vcc,
					    data_addr, len );
				    /*
				     * Adjust remaining length
				     */
				    pdulen -= len;
				    /*
				     * Set buffer length
				     */
				    KB_LEN ( m1 ) = len;
				    /*
				     * Link new buffer onto end and advance
				     * pointer
				     */
				    KB_NEXT ( m0 ) = m1;
				    m0 = m1;
				} else {
				    /*
				     * Either we were unable to grab another
				     * buffer or there are no large buffers
				     * available. We know that the first
				     * buffer is valid, so drop everything
				     * else, build a JK DMA to skip/drop this
				     * PDU, set the pointers to reclaim
				     * resources/advance pointers, and
				     * finish this PDU now.
				     */
				    if ( KB_NEXT ( m ) )
				    	KB_FREEALL ( KB_NEXT ( m ) );
				    eup->eu_pif.pif_ierrors++;
				    j = 2;
				    dma[j++] =
				        (((rdptr + n_cells*WORDS_PER_CELL + 1)
					    & (mask-1)) << DMA_COUNT_SHIFT ) |
					        (vcc << DMA_VCC_SHIFT ) |