sonic.c

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

}

/*
 * Send packet
 */
SONIC_STATIC void sonic_sendpacket (struct ifnet *ifp, struct mbuf *m)
{
  struct sonic_softc *sc = ifp->if_softc;
  struct mbuf *l = NULL;
  TransmitDescriptorPointer_t tdp;
  volatile struct TransmitDescriptorFragLink *fp;
  unsigned int packetSize;
  int i;
  rtems_event_set events;
  static char padBuf[64];

  /* printf( "sonic_sendpacket %p\n", m ); */


  /*
   * Wait for transmit descriptor to become available. Only retire TDA's
   * if there are no more free buffers to minimize TX latency. Retire TDA'a
   * on the way out.
   */

  while (sc->tdaHead->next->status != 0) {
  
  /*
   * Free up transmit descriptors
   */
    sonic_retire_tda (sc);

    if (sc->tdaHead->next->status == 0) 
      break;

#if (SONIC_DEBUG & SONIC_DEBUG_ERRORS)
    printf("blocking until TDAs are available\n");
#endif
      /*
       * Enable PINT interrupts.
    sonic_clear_interrupts( sc, ISR_PINT );
    sonic_enable_interrupts( sc, IMR_PINTEN );
       */

      /*
       * Wait for PINT TX interrupt. Every fourth TX buffer will raise PINT.
       */
    rtems_bsdnet_event_receive (INTERRUPT_EVENT,
            RTEMS_WAIT|RTEMS_EVENT_ANY,
            RTEMS_NO_TIMEOUT,
            &events);
    sonic_disable_interrupts( sc, IMR_PINTEN );
    sonic_retire_tda (sc);
  }

  /*
   * Fill in the transmit descriptor fragment descriptors.
   * ===CACHE===
   * If data cache is operating in write-back mode, flush cached
   * data to memory.
   */
  tdp = sc->tdaHead->next;
  tdp->mbufp = m;
  packetSize = 0;
  fp = tdp->frag;
  for (i = 0 ; i < MAXIMUM_FRAGS_PER_DESCRIPTOR ; i++, fp++) {
    /*
     * Throw away empty mbufs
     */
    if (m->m_len) {
      void *p = mtod (m, void *);
      fp->frag_lsw = LSW(p);
      fp->frag_msw = MSW(p);
      fp->frag_size = m->m_len;
      packetSize += m->m_len;
#if (SONIC_DEBUG & SONIC_DEBUG_FRAGMENTS)
      printf( "fp %p 0x%04x%04x %d=%d .. %d\n",
        fp, fp->frag_msw, fp->frag_lsw, fp->frag_size, m->m_len, packetSize );
#endif
#if (SONIC_DEBUG & SONIC_DEBUG_DUMP_TX_MBUFS)
      Dump_Buffer(
        p,
        (fp->frag_size > MAXIMUM_FRAME_SIZE) ? MAXIMUM_FRAME_SIZE : fp->frag_size
      );
#endif
      l = m;
      m = m->m_next;
    }
    else {
      struct mbuf *n;
      MFREE (m, n);
      m = n;
      if (l != NULL)
        l->m_next = m;
    }
    /*
     * Break out of the loop if this mbuf is the last in the frame.
     */
    if (m == NULL)
      break;
  }

  /*
   * Pad short packets.
   */
  if  ((packetSize < 64) && (i < MAXIMUM_FRAGS_PER_DESCRIPTOR)) {
    int padSize = 64 - packetSize;
    fp++;
    fp->frag_lsw = LSW(padBuf);
    fp->frag_msw = MSW(padBuf);
    fp->frag_size = padSize;
#if (SONIC_DEBUG & SONIC_DEBUG_FRAGMENTS)
    printf( "PAD fp %p 0x%04x%04x %d\n",
         fp, fp->frag_msw, fp->frag_lsw, fp->frag_size );
#endif
    packetSize += padSize;
    i++;
  }

  /*
   * Fill Transmit Descriptor
   */
  tdp->pkt_size = packetSize;
  tdp->frag_count = i + 1;
  tdp->status = 0;

  /*
   * Chain onto list and start transmission.
   */

  tdp->linkp = &(fp+1)->frag_link;
  *tdp->linkp = LSW(tdp->next) | TDA_LINK_EOL;
  if ( sc->tdaHead->frag_count )
    *sc->tdaHead->linkp &= ~TDA_LINK_EOL;
  sc->tdaHead = tdp;

  /* Start transmission */

  sonic_command(sc, CR_TXP );

  /*
   * Free up transmit descriptors on the way out.
   */
  sonic_retire_tda (sc);
}

/*
 * Driver transmit daemon
 */
SONIC_STATIC void sonic_txDaemon (void *arg)
{
  struct sonic_softc *sc = (struct sonic_softc *)arg;
  struct ifnet *ifp = &sc->arpcom.ac_if;
  struct mbuf *m;
  rtems_event_set events;

  for (;;) {
    /*
     * Wait for packet
     */
    rtems_bsdnet_event_receive (
       START_TRANSMIT_EVENT,
       RTEMS_EVENT_ANY | RTEMS_WAIT,
       RTEMS_NO_TIMEOUT,
       &events
    );

    /*
     * Send packets till queue is empty
     */
    for (;;) {
      /*
       * Get the next mbuf chain to transmit.
       */
      IF_DEQUEUE(&ifp->if_snd, m);
      if (!m)
        break;
      sonic_sendpacket (ifp, m);
    }
    ifp->if_flags &= ~IFF_OACTIVE;
  }
}

/*
 ******************************************************************
 *                                                                *
 *                        Receiver Routines                       *
 *                                                                *
 ******************************************************************
 */

/*
 * Wait for SONIC to hand over a Receive Descriptor.
 */

SONIC_STATIC void sonic_rda_wait(
  struct sonic_softc *sc,
  ReceiveDescriptorPointer_t rdp
)
{
  int i;
  void *rp = sc->sonic;
  rtems_event_set events;

  /*
   * Wait for Receive Descriptor.
   * The order of the tests is very important.
   *    The RDA is checked after RBAE is detected.  This ensures that
   *    the driver processes all RDA entries before reusing the RRA
   *    entry holding the giant packet.
   *    The event wait is done after the RDA and RBAE checks.  This
   *    catches the possibility that a Receive Descriptor became ready
   *    between the call to this function and the clearing of the
   *    interrupt status register bit.
   */
  for (;;) {
    /*
     * Has a giant packet arrived?
     * The National DP83932C data sheet is very vague on what
     * happens under this condition.  The description of the
     * Interrupt Status Register (Section 4.3.6) states,
     * ``Reception is aborted and the SONIC fetches the next
     * available resource descriptors in the RRA.  The buffer
     * space is not re-used and an RDA is not setup for the
     * truncated packet.''
     * I take ``Reception is aborted''  to mean that the RXEN
     * bit in the Command Register is cleared and must be set
     * by the driver to begin reception again.
     * Unfortunately, an alternative interpretation could be
     * that only reception of the current packet is aborted.
     * This would be more difficult to recover from....
     */
    if ((*sc->read_register)( rp, SONIC_REG_ISR ) & ISR_RBAE) {

#if (SONIC_DEBUG & SONIC_DEBUG_ERRORS)
      printf( "ERROR: looks like a giant packet -- RBAE\n" );
#endif

      /*
       * One more check to soak up any Receive Descriptors
       * that may already have been handed back to the driver.
       */
      if (rdp->in_use == RDA_IN_USE) {
#if (SONIC_DEBUG & SONIC_DEBUG_ERRORS)
      printf( "ERROR: nope just an RBAE\n" );
#endif
        break;
      }

      /*
       * Check my interpretation of the SONIC manual.
       */
      if ((*sc->read_register)( rp, SONIC_REG_CR ) & CR_RXEN)
        rtems_panic ("SONIC RBAE/RXEN");

      /*
       * Update statistics
       */
      sc->rxGiant++;

      /*
       * Reuse receive buffer.
       * Again, the manual is subject to interpretation.  The
       * RRP register is described as, `the lower address of
       * the next descriptor the SONIC will read.''
       * Since, acording to the ISR/RBAE notes, the SONIC has
       * ``fetched the next available resource descriptor in
       * the RRA'', I interpret this to mean that that the
       * driver has to move the RRP back *two* entries to
       * reuse the receive buffer holding the giant packet.
       */
      for (i = 0 ; i < 2 ; i++) {
        if ((*sc->read_register)( rp, SONIC_REG_RRP ) ==
            (*sc->read_register)( rp, SONIC_REG_RSA ))
          (*sc->write_register)(
            rp,
            SONIC_REG_RRP,
            (*sc->read_register)( rp, SONIC_REG_REA )
          );
          (*sc->write_register)(
             rp,
             SONIC_REG_RRP,
             (*sc->read_register)(rp, SONIC_REG_RRP) - sizeof(ReceiveResource_t)
          );
      }

      /*
       * Restart reception
       */
      sonic_clear_interrupts( sc, ISR_RBAE );
      sonic_command( sc, CR_RXEN );
    }

    /*
     * Has Receive Descriptor become available?
     */
    if (rdp->in_use == RDA_IN_USE)
      break;

    /*
     * Enable interrupts.
     */
    sonic_enable_interrupts( sc, (IMR_PRXEN | IMR_RBAEEN) );

    /*
     * Wait for interrupt.
     */
    rtems_bsdnet_event_receive(
      INTERRUPT_EVENT,
      RTEMS_WAIT|RTEMS_EVENT_ANY,
      RTEMS_NO_TIMEOUT,
      &events
    );
  }
#if (SONIC_DEBUG & SONIC_DEBUG_DESCRIPTORS)
  printf( "RDA %p\n", rdp );
#endif

#if (SONIC_DEBUG & SONIC_DEBUG_ERRORS)
    if (rdp->status & 0x000E)
      printf( "ERROR: RDA %p (0x%04x)\n", rdp, rdp->status );
#endif

}

#ifdef CPU_U32_FIX

/*
 * Routine to align the received packet so that the ip header
 * is on a 32-bit boundary. Necessary for cpu's that do not
 * allow unaligned loads and stores and when the 32-bit DMA
 * mode is used. 
 * 
 * Transfers are done on word basis to avoid possibly slow byte 
 * and half-word writes.
 */
 
void ipalign(struct mbuf *m)
{
  unsigned int *first, *last, data;
  unsigned int tmp = 0;

  if ((((int) m->m_data) & 2) && (m->m_len)) {
    last = (unsigned int *) ((((int) m->m_data) + m->m_len + 8) & ~3);
    first = (unsigned int *) (((int) m->m_data) & ~3);
    tmp = *first << 16;
    first++;
    do {
      data = *first;
      *first = tmp | (data >> 16);
      tmp = data << 16;
      first++;
    } while (first <= last);

    m->m_data = (caddr_t)(((int) m->m_data) + 2);
  }
}
#endif

/*
 * SONIC reader task
 */
SONIC_STATIC void sonic_rxDaemon (void *arg)
{
  struct sonic_softc *sc = (struct sonic_softc *)arg;
  struct ifnet *ifp = &sc->arpcom.ac_if;
  void *rp = sc->sonic;
  struct mbuf *m;
  rtems_unsigned16 status;
  ReceiveDescriptorPointer_t rdp;
  ReceiveResourcePointer_t rwp, rea;
  rtems_unsigned16 newMissedTally, oldMissedTally;

  rwp = sc->rsa;
  rea = sc->rea;
  rdp = sc->rda;

  /*
   * Start the receiver
   */
  oldMissedTally = (*sc->read_register)( rp, SONIC_REG_MPT );

  /*
   * Input packet handling loop
   */
  for (;;) {
    /*
     * Wait till SONIC supplies a Receive Descriptor.
     */
    if (rdp->in_use == RDA_FREE) {
      sonic_rda_wait (sc, rdp);
    }

#if (SONIC_DEBUG & SONIC_DEBUG_DESCRIPTORS)
    printf( "Incoming packet %p status=0x%04x\n", rdp, rdp->status );
#endif

    /*
     * Check that packet is valid
     */
    status = rdp->status;
    if (status & RDA_STATUS_PRX) {
      struct ether_header *eh;
      void *p;

      /*
       * Pass the packet up the chain.
       * The mbuf count is reduced to remove
       * the frame check sequence at the end
       * of the packet.
       * ===CACHE===
       * Invalidate cache entries for this memory.
       */
#if (SONIC_DEBUG & SONIC_DEBUG_MEMORY_DESCRIPTORS)
      sonic_print_rx_descriptor( rdp );
      if ((LSW(rdp->mbufp->m_data) != rdp->pkt_lsw)
       || (MSW(rdp->mbufp->m_data) != rdp->pkt_msw))
        printf ("SONIC RDA/RRA %p, %08x\n",rdp->mbufp->m_data,(rdp->pkt_msw << 16) | 
	(rdp->pkt_lsw & 0x0ffff));
#endif
      rdp->byte_count &= 0x0ffff;    /* ERC32 pollutes msb of byte_count */
      m = rdp->mbufp;
      m->m_len = m->m_pkthdr.len = rdp->byte_count -
                          sizeof(rtems_unsigned32) -
                          sizeof(struct ether_header);
      eh = mtod (m, struct ether_header *);
      m->m_data += sizeof(struct ether_header);
  
#ifdef CPU_U32_FIX
      ipalign(m);	/* Align packet on 32-bit boundary */
#endif

#if (SONIC_DEBUG & SONIC_DEBUG_DUMP_RX_MBUFS)
      Dump_Buffer( (void *) eh, sizeof(struct ether_header) );
      Dump_Buffer( (void *) m, 96 /* m->m_len*/ );
#endif

      /* printf( "ether_input %p\n", m ); */
      /*
      printf( "pkt %p, seq %04x, mbuf %p, m_data %p\n", rdp, rdp->seq_no, m, m->m_data );
      printf( "%u, %u\n", ((int*)m->m_data)[6], ((int*)m->m_data)[7]);
      */
      ether_input (ifp, eh, m);
      /*
      */

      /*
       * Sanity check that Receive Resource Area is
       * still in sync with Receive Descriptor Area
       * The buffer reported in the Receive Descriptor
       * should be the same as the buffer in the Receive
       * Resource we are about to reuse.
       */
/* XXX figure out whether this is valid or not */
#if 0
      if ((LSW(p) != rwp->buff_ptr_lsw)
       || (MSW(p) != rwp->buff_ptr_msw))
        rtems_panic ("SONIC RDA/RRA");
#endif

      /*
       * Allocate a new mbuf.
       */

      MGETHDR (m, M_WAIT, MT_DATA);
      MCLGET (m, M_WAIT);
      m->m_pkthdr.rcvif = ifp;
      rdp->mbufp = m;
      p = mtod (m, void *);

      /*
       * Reuse Receive Resource.
       */

      rwp->buff_ptr_lsw = LSW(p);
      rwp->buff_ptr_msw = MSW(p);
      rwp->buff_wc_lsw = RBUF_WC;
      rwp->buff_wc_msw = 0;
      rwp++;

      if (rwp == rea) {
#if (SONIC_DEBUG & SONIC_DEBUG_MEMORY)
        printf( "Wrapping RWP from %p to %p\n", rwp, sc->rsa );
#endif
        rwp = sc->rsa;
      }
      (*sc->write_register)( rp, SONIC_REG_RWP , LSW(rwp) );

      /*
       * Tell the SONIC to reread the RRA.
       */
      if ((*sc->read_register)( rp, SONIC_REG_ISR ) & ISR_RBE)
      sonic_clear_interrupts( sc, ISR_RBE );
    }
    else {
      if (status & RDA_STATUS_COL)
        sc->rxCollision++;
      if (status & RDA_STATUS_FAER)
        sc->rxNonOctet++;
      else if (status & RDA_STATUS_CRCR)
        sc->rxBadCRC++;
    }

    /*
     * Count missed packets
     */
    newMissedTally = (*sc->read_register)( rp, SONIC_REG_MPT );
    if (newMissedTally != oldMissedTally) {
      sc->rxMissed += (newMissedTally - oldMissedTally) & 0xFFFF;
      newMissedTally = oldMissedTally;
    }

    /*
     * Move to next receive descriptor and update EOL
     */

    rdp->link |= RDA_LINK_EOL;
    rdp->in_use = RDA_FREE;
    sc->rdp_last->link &= ~RDA_LINK_EOL;
    sc->rdp_last = rdp;
    rdp = rdp->next;

  }
}

/*
 ******************************************************************
 *                                                                *
 *                     Initialization Routines                    *
 *                                                                *
 ******************************************************************
 */

/*
 * Initialize the SONIC hardware
 */
SONIC_STATIC void sonic_initialize_hardware(struct sonic_softc *sc)
{
  void *rp = sc->sonic;
  int i;
  unsigned char *hwaddr;
  rtems_isr_entry old_handler;
  TransmitDescriptorPointer_t tdp;
  ReceiveDescriptorPointer_t ordp, rdp;
  ReceiveResourcePointer_t rwp;
  struct mbuf *m;
  void *p;
  CamDescriptorPointer_t cdp;

  /*
   *  The Revision B SONIC has a horrible bug known as the "Zero
   *  Length Packet bug".  The initial board used to develop this
   *  driver had a newer revision of the SONIC so there was no reason
   *  to check for this.  If you have the Revision B SONIC chip, then
   *  you need to add some code to the RX path to handle this weirdness.
   */

  if ( (*sc->read_register)( rp, SONIC_REG_SR ) <= SONIC_REVISION_B ) {
    rtems_fatal_error_occurred( 0x0BADF00D );  /* don't eat this part :) */
  }
  
  /*
   *  Set up circular linked list in Transmit Descriptor Area.
   *  Use the PINT bit in the transmit configuration field to