network.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

   * Set up receive buffer descriptors
   */
  for (i = 0 ; i < sc->rxBdCount ; i++)
    (sc->rxBdBase + i)->status = 0;
  
  /*
   * Set up transmit buffer descriptors
   */
  for (i = 0 ; i < sc->txBdCount ; i++) {
    (sc->txBdBase + i)->status = 0;
    sc->txMbuf[i] = NULL;
  }
  sc->txBdHead = sc->txBdTail = 0;
  sc->txBdActiveCount = 0;
  
  

  /*
   * Mask all FEC interrupts and clear events
   */
  m8xx.fec.imask = M8xx_FEC_IEVENT_TFINT | 
                   M8xx_FEC_IEVENT_RFINT;
  m8xx.fec.ievent = ~0;

  /*
   * Set up interrupts
   */
  if (!BSP_install_rtems_irq_handler (&ethernetFECIrqData))
    rtems_panic ("Can't attach M860 FEC interrupt handler\n", 0);

}


/*
 * Soak up buffer descriptors that have been sent
 * Note that a buffer descriptor can't be retired as soon as it becomes
 * ready.  The MC68360 Errata (May 96) says that, "If an Ethernet frame is
 *  made up of multiple buffers, the user should not reuse the first buffer
 * descriptor until the last buffer descriptor of the frame has had its
 * ready bit cleared by the CPM".
 */
static void
m860Enet_retire_tx_bd (struct m860_enet_struct *sc)
{
  rtems_unsigned16 status;
  int i;
  int nRetired;
  struct mbuf *m, *n;
  
  i = sc->txBdTail;
  nRetired = 0;
  while ((sc->txBdActiveCount != 0)
         &&  (((status = (sc->txBdBase + i)->status) & M8xx_BD_READY) == 0)) {
    /*
     * See if anything went wrong
     */
    if (status & (M8xx_BD_DEFER |
                  M8xx_BD_HEARTBEAT |
                  M8xx_BD_LATE_COLLISION |
                  M8xx_BD_RETRY_LIMIT |
                  M8xx_BD_UNDERRUN |
                  M8xx_BD_CARRIER_LOST)) {
      /*
       * Check for errors which stop the transmitter.
       */
      if (status & (M8xx_BD_LATE_COLLISION |
                    M8xx_BD_RETRY_LIMIT |
                    M8xx_BD_UNDERRUN)) {
        if (status & M8xx_BD_LATE_COLLISION)
          enet_driver[0].txLateCollision++;
        if (status & M8xx_BD_RETRY_LIMIT)
          enet_driver[0].txRetryLimit++;
        if (status & M8xx_BD_UNDERRUN)
          enet_driver[0].txUnderrun++;
        
        /*
         * Restart the transmitter
         */
        /* FIXME: this should get executed only if using the SCC */
        m8xx_cp_execute_cmd (M8xx_CR_OP_RESTART_TX | M8xx_CR_CHAN_SCC1);
      }
      if (status & M8xx_BD_DEFER)
        enet_driver[0].txDeferred++;
      if (status & M8xx_BD_HEARTBEAT)
        enet_driver[0].txHeartbeat++;
      if (status & M8xx_BD_CARRIER_LOST)
        enet_driver[0].txLostCarrier++;
    }
    nRetired++;
    if (status & M8xx_BD_LAST) {
      /*
       * A full frame has been transmitted.
       * Free all the associated buffer descriptors.
       */
      sc->txBdActiveCount -= nRetired;
      while (nRetired) {
        nRetired--;
        m = sc->txMbuf[sc->txBdTail];
        MFREE (m, n);
        if (++sc->txBdTail == sc->txBdCount)
          sc->txBdTail = 0;
      }
    }
    if (++i == sc->txBdCount)
      i = 0;
  }
}

/*
 * reader task
 */
static void
scc_rxDaemon (void *arg)
{
  struct m860_enet_struct *sc = (struct m860_enet_struct *)arg;
  struct ifnet *ifp = &sc->arpcom.ac_if;
  struct mbuf *m;
  rtems_unsigned16 status;
  m8xxBufferDescriptor_t *rxBd;
  int rxBdIndex;
  
  /*
   * Allocate space for incoming packets and start reception
   */
  for (rxBdIndex = 0 ; ;) {
    rxBd = sc->rxBdBase + rxBdIndex;
    MGETHDR (m, M_WAIT, MT_DATA);
    MCLGET (m, M_WAIT);
    m->m_pkthdr.rcvif = ifp;
    sc->rxMbuf[rxBdIndex] = m;
    rxBd->buffer = mtod (m, void *);
    rxBd->status = M8xx_BD_EMPTY | M8xx_BD_INTERRUPT;
    if (++rxBdIndex == sc->rxBdCount) {
      rxBd->status |= M8xx_BD_WRAP;
      break;
    }
  }
  
  /*
   * Input packet handling loop
   */
  rxBdIndex = 0;
  for (;;) {
    rxBd = sc->rxBdBase + rxBdIndex;
    
    /*
     * Wait for packet if there's not one ready
     */
    if ((status = rxBd->status) & M8xx_BD_EMPTY) {
      /*
       * Clear old events
       */
      m8xx.scc1.scce = 0x8;
      
      /*
       * Wait for packet
       * Note that the buffer descriptor is checked
       * *before* the event wait -- this catches the
       * possibility that a packet arrived between the
       * `if' above, and the clearing of the event register.
       */
      while ((status = rxBd->status) & M8xx_BD_EMPTY) {
        rtems_event_set events;
        
        /*
         * Unmask RXF (Full frame received) event
         */
        m8xx.scc1.sccm |= 0x8;
        
        rtems_bsdnet_event_receive (INTERRUPT_EVENT,
                                    RTEMS_WAIT|RTEMS_EVENT_ANY,
                                    RTEMS_NO_TIMEOUT,
                                    &events);
      }
    }
    
    /*
     * Check that packet is valid
     */
    if ((status & (M8xx_BD_LAST |
                   M8xx_BD_FIRST_IN_FRAME |
                   M8xx_BD_LONG |
                   M8xx_BD_NONALIGNED |
                   M8xx_BD_SHORT |
                   M8xx_BD_CRC_ERROR |
                   M8xx_BD_OVERRUN |
                   M8xx_BD_COLLISION)) ==
        (M8xx_BD_LAST |
         M8xx_BD_FIRST_IN_FRAME)) {
      /*
       * Pass the packet up the chain.
       * FIXME: Packet filtering hook could be done here.
       */
      struct ether_header *eh;
      
      m = sc->rxMbuf[rxBdIndex];
      m->m_len = m->m_pkthdr.len = rxBd->length -
        sizeof(rtems_unsigned32) -
        sizeof(struct ether_header);
      eh = mtod (m, struct ether_header *);
      m->m_data += sizeof(struct ether_header);
      ether_input (ifp, eh, m);
      
      /*
       * Allocate a new mbuf
       */
      MGETHDR (m, M_WAIT, MT_DATA);
      MCLGET (m, M_WAIT);
      m->m_pkthdr.rcvif = ifp;
      sc->rxMbuf[rxBdIndex] = m;
      rxBd->buffer = mtod (m, void *);
    }
    else {
      /*
       * Something went wrong with the reception
       */
      if (!(status & M8xx_BD_LAST))
        sc->rxNotLast++;
      if (!(status & M8xx_BD_FIRST_IN_FRAME))
        sc->rxNotFirst++;
      if (status & M8xx_BD_LONG)
        sc->rxGiant++;
      if (status & M8xx_BD_NONALIGNED)
        sc->rxNonOctet++;
      if (status & M8xx_BD_SHORT)
        sc->rxRunt++;
      if (status & M8xx_BD_CRC_ERROR)
        sc->rxBadCRC++;
      if (status & M8xx_BD_OVERRUN)
        sc->rxOverrun++;
      if (status & M8xx_BD_COLLISION)
        sc->rxCollision++;
    }
    
    /*
     * Reenable the buffer descriptor
     */
    rxBd->status = (status & (M8xx_BD_WRAP | M8xx_BD_INTERRUPT)) |
                    M8xx_BD_EMPTY;
    
    /*
     * Move to next buffer descriptor
     */
    if (++rxBdIndex == sc->rxBdCount)
      rxBdIndex = 0;
  }
}

static void
fec_rxDaemon (void *arg)
{
  struct m860_enet_struct *sc = (struct m860_enet_struct *)arg;
  struct ifnet *ifp = &sc->arpcom.ac_if;
  struct mbuf *m;
  rtems_unsigned16 status;
  m8xxBufferDescriptor_t *rxBd;
  int rxBdIndex;
  
  /*
   * Allocate space for incoming packets and start reception
   */
  for (rxBdIndex = 0 ; ;) {
    rxBd = sc->rxBdBase + rxBdIndex;
    MGETHDR (m, M_WAIT, MT_DATA);
    MCLGET (m, M_WAIT);
    m->m_pkthdr.rcvif = ifp;
    sc->rxMbuf[rxBdIndex] = m;
    rxBd->buffer = mtod (m, void *);
    rxBd->status = M8xx_BD_EMPTY;
    m8xx.fec.r_des_active = 0x1000000;
    if (++rxBdIndex == sc->rxBdCount) {
      rxBd->status |= M8xx_BD_WRAP;
      break;
    }
  }
  
  /*
   * Input packet handling loop
   */
  rxBdIndex = 0;
  for (;;) {
    rxBd = sc->rxBdBase + rxBdIndex;
    
    /*
     * Wait for packet if there's not one ready
     */
    if ((status = rxBd->status) & M8xx_BD_EMPTY) {
      /*
       * Clear old events
       */
      m8xx.fec.ievent = M8xx_FEC_IEVENT_RFINT;
      
      /*
       * Wait for packet
       * Note that the buffer descriptor is checked
       * *before* the event wait -- this catches the
       * possibility that a packet arrived between the
       * `if' above, and the clearing of the event register.
       */
      while ((status = rxBd->status) & M8xx_BD_EMPTY) {
        rtems_event_set events;
        
        /*
         * Unmask RXF (Full frame received) event
         */
        m8xx.fec.ievent |= M8xx_FEC_IEVENT_RFINT;
        
        rtems_bsdnet_event_receive (INTERRUPT_EVENT,
                                    RTEMS_WAIT|RTEMS_EVENT_ANY,
                                    RTEMS_NO_TIMEOUT,
                                    &events);
      }
    }
    
    /*
     * Check that packet is valid
     */
    if (status & M8xx_BD_LAST) {
      /*
       * Pass the packet up the chain.
       * FIXME: Packet filtering hook could be done here.
       */
      struct ether_header *eh;
      
      m = sc->rxMbuf[rxBdIndex];
      m->m_len = m->m_pkthdr.len = rxBd->length -
        sizeof(rtems_unsigned32) -
        sizeof(struct ether_header);
      eh = mtod (m, struct ether_header *);
      m->m_data += sizeof(struct ether_header);
      ether_input (ifp, eh, m);
      
      /*
       * Allocate a new mbuf
       */
      MGETHDR (m, M_WAIT, MT_DATA);
      MCLGET (m, M_WAIT);
      m->m_pkthdr.rcvif = ifp;
      sc->rxMbuf[rxBdIndex] = m;
      rxBd->buffer = mtod (m, void *);
    }
    else {
      /*
       * Something went wrong with the reception
       */
      if (!(status & M8xx_BD_LAST))
        sc->rxNotLast++;
      if (status & M8xx_BD_LONG)
        sc->rxGiant++;
      if (status & M8xx_BD_NONALIGNED)
        sc->rxNonOctet++;
      if (status & M8xx_BD_SHORT)
        sc->rxRunt++;
      if (status & M8xx_BD_CRC_ERROR)
        sc->rxBadCRC++;
      if (status & M8xx_BD_OVERRUN)
        sc->rxOverrun++;
      if (status & M8xx_BD_COLLISION)
        sc->rxCollision++;
    }
    /*
     * Reenable the buffer descriptor
     */
    rxBd->status = (status & M8xx_BD_WRAP) |
                    M8xx_BD_EMPTY;
    m8xx.fec.r_des_active = 0x1000000;
    /*
     * Move to next buffer descriptor
     */
    if (++rxBdIndex == sc->rxBdCount)
      rxBdIndex = 0;
  }
}

static void
scc_sendpacket (struct ifnet *ifp, struct mbuf *m)
{
  struct m860_enet_struct *sc = ifp->if_softc;
  volatile m8xxBufferDescriptor_t *firstTxBd, *txBd;
  struct mbuf *l = NULL;
  rtems_unsigned16 status;
  int nAdded;
  
  /*
   * Free up buffer descriptors
   */
  m860Enet_retire_tx_bd (sc);
  
  /*
   * Set up the transmit buffer descriptors.
   * No need to pad out short packets since the
   * hardware takes care of that automatically.
   * No need to copy the packet to a contiguous buffer
   * since the hardware is capable of scatter/gather DMA.
   */
  nAdded = 0;
  txBd = firstTxBd = sc->txBdBase + sc->txBdHead;
  for (;;) {
    /*
     * Wait for buffer descriptor to become available.
     */
    if ((sc->txBdActiveCount + nAdded) == sc->txBdCount) {
      /*
       * Clear old events
       */
      m8xx.scc1.scce = 0x12;
      
      /*
       * Wait for buffer descriptor to become available.
       * Note that the buffer descriptors are checked
       * *before* * entering the wait loop -- this catches
       * the possibility that a buffer descriptor became
       * available between the `if' above, and the clearing
       * of the event register.
       * This is to catch the case where the transmitter
       * stops in the middle of a frame -- and only the
       * last buffer descriptor in a frame can generate
       * an interrupt.
       */
      m860Enet_retire_tx_bd (sc);
      while ((sc->txBdActiveCount + nAdded) == sc->txBdCount) {
        rtems_event_set events;
        
                                /*
                                 * Unmask TXB (buffer transmitted) and
                                 * TXE (transmitter error) events.
                                 */
        m8xx.scc1.sccm |= 0x12;
        rtems_bsdnet_event_receive (INTERRUPT_EVENT,
                                    RTEMS_WAIT|RTEMS_EVENT_ANY,
                                    RTEMS_NO_TIMEOUT,
                                    &events);
        m860Enet_retire_tx_bd (sc);
      }
    }
    
    /*
     * Don't set the READY flag till the
     * whole packet has been readied.
     */
    status = nAdded ? M8xx_BD_READY : 0;
    
    /*
     *  FIXME: Why not deal with empty mbufs at at higher level?
     * The IP fragmentation routine in ip_output
     * can produce packet fragments with zero length.
     * I think that ip_output should be changed to get
     * rid of these zero-length mbufs, but for now,
     * I'll deal with them here.
     */
    if (m->m_len) {
      /*
       * Fill in the buffer descriptor
       */
      txBd->buffer = mtod (m, void *);
      txBd->length = m->m_len;
      sc->txMbuf[sc->txBdHead] = m;
      nAdded++;
      if (++sc->txBdHead == sc->txBdCount) {
        status |= M8xx_BD_WRAP;
        sc->txBdHead = 0;
      }
      l = m;
      m = m->m_next;
    }
    else {
      /*
       * Just toss empty mbufs
       */
      struct mbuf *n;
      MFREE (m, n);
      m = n;
      if (l != NULL)
        l->m_next = m;
    }
    
    /*
     * Set the transmit buffer status.
     * Break out of the loop if this mbuf is the last in the frame.
     */
    if (m == NULL) {
      if (nAdded) {
        status |= M8xx_BD_PAD | M8xx_BD_LAST | M8xx_BD_TX_CRC | M8xx_BD_INTERRUPT;
        txBd->status = status;
        firstTxBd->status |= M8xx_BD_READY;
        sc->txBdActiveCount += nAdded;
      }
      break;
    }
    txBd->status = status;
    txBd = sc->txBdBase + sc->txBdHead;
  }
}

static void
fec_sendpacket (struct ifnet *ifp, struct mbuf *m)
{
  struct m860_enet_struct *sc = ifp->if_softc;
  volatile m8xxBufferDescriptor_t *firstTxBd, *txBd;
  /*  struct mbuf *l = NULL; */
  rtems_unsigned16 status;
  int nAdded;
  
  /*
   * Free up buffer descriptors
   */
  m860Enet_retire_tx_bd (sc);
  
  /*
   * Set up the transmit buffer descriptors.
   * No need to pad out short packets since the
   * hardware takes care of that automatically.
   * No need to copy the packet to a contiguous buffer
   * since the hardware is capable of scatter/gather DMA.
   */
  nAdded = 0;
  txBd = firstTxBd = sc->txBdBase + sc->txBdHead;
  for (;;) {
    /*
     * Wait for buffer descriptor to become available.
     */
    if ((sc->txBdActiveCount + nAdded) == sc->txBdCount) {
      /*
       * Clear old events
       */
      m8xx.fec.ievent = M8xx_FEC_IEVENT_TFINT;
      
      /*
       * Wait for buffer descriptor to become available.
       * Note that the buffer descriptors are checked
       * *before* * entering the wait loop -- this catches
       * the possibility that a buffer descriptor became
       * available between the `if' above, and the clearing
       * of the event register.
       * This is to catch the case where the transmitter
       * stops in the middle of a frame -- and only the
       * last buffer descriptor in a frame can generate
       * an interrupt.
       */
      m860Enet_retire_tx_bd (sc);
      while ((sc->txBdActiveCount + nAdded) == sc->txBdCount) {
        rtems_event_set events;