i82586.c

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

 */
static int
i82586_get_rbd_list(struct ie_softc *sc, u_int16_t *start, u_int16_t *end, int *pktlen)
{
  int  off, rbbase = sc->rbds;
  int  rbindex, count = 0;
  int  plen = 0;
  int  rbdstatus;

  *start = rbindex = sc->rbhead;

  do {
    off = IE_RBD_STATUS(rbbase, rbindex);
    IE_BUS_BARRIER(sc, off, 2, BUS_SPACE_BARRIER_READ);
    rbdstatus = sc->ie_bus_read16(sc, off);
    if ((rbdstatus & IE_RBD_USED) == 0) {
      /*
       * This means we are somehow out of sync.  So, we
       * reset the adapter.
       */
#if I82586_DEBUG
      print_rbd(sc, rbindex);
#endif
      printf("%s: receive descriptors out of sync at %d\n",
             sc->arpcom.ac_if.if_name, rbindex);
      return (0);
    }
    plen += (rbdstatus & IE_RBD_CNTMASK);

    if (++rbindex == sc->nrxbuf)
      rbindex = 0;

    ++count;
  } while ((rbdstatus & IE_RBD_LAST) == 0);
  *end = rbindex;
  *pktlen = plen;
  return (count);
}


/*
 * Release a range of receive buffer descriptors after we've copied the packet.
 */
static void
i82586_release_rbd_list(struct ie_softc *sc, u_int16_t start, u_int16_t end)
{
  int  off, rbbase = sc->rbds;
  int  rbindex = start;

  do {
    /* Clear buffer status */
    off = IE_RBD_STATUS(rbbase, rbindex);
    sc->ie_bus_write16(sc, off, 0);
    if (++rbindex == sc->nrxbuf)
      rbindex = 0;
  } while (rbindex != end);

  /* Mark EOL at new tail */
  rbindex = ((rbindex == 0) ? sc->nrxbuf : rbindex) - 1;
  off = IE_RBD_BUFLEN(rbbase, rbindex);
  sc->ie_bus_write16(sc, off, IE_RBUF_SIZE|IE_RBD_EOL);

  /* Remove EOL from current tail */
  off = IE_RBD_BUFLEN(rbbase, sc->rbtail);
  sc->ie_bus_write16(sc, off, IE_RBUF_SIZE);

  /* New head & tail pointer */
/* hmm, why have both? head is always (tail + 1) % NRXBUF */
  sc->rbhead = end;
  sc->rbtail = rbindex;
}

/*
 * Drop the packet at the head of the RX buffer ring.
 * Called if the frame descriptor reports an error on this packet.
 * Returns 1 if the buffer descriptor ring appears to be corrupt;
 * and 0 otherwise.
 */
static int
i82586_drop_frames(struct ie_softc *sc)
{
  u_int16_t bstart, bend;
  int pktlen;

  if (i82586_get_rbd_list(sc, &bstart, &bend, &pktlen) == 0)
    return (1);
  i82586_release_rbd_list(sc, bstart, bend);
  return (0);
}

/*
 * Check the RX frame & buffer descriptor lists for our invariants,
 * i.e.: EOL bit set iff. it is pointed at by the r*tail pointer.
 *
 * Called when the receive unit has stopped unexpectedly.
 * Returns 1 if an inconsistency is detected; 0 otherwise.
 *
 * The Receive Unit is expected to be NOT RUNNING.
 */
static int
i82586_chk_rx_ring(struct ie_softc *sc)
{
  int n, off, val;

  for (n = 0; n < sc->nrxbuf; n++) {
    off = IE_RBD_BUFLEN(sc->rbds, n);
    val = sc->ie_bus_read16(sc, off);
    if ((n == sc->rbtail) ^ ((val & IE_RBD_EOL) != 0)) {
      /* `rbtail' and EOL flag out of sync */
      printf("%s: rx buffer descriptors out of sync at %d\n",
             sc->arpcom.ac_if.if_name, n);
      return (1);
    }

    /* Take the opportunity to clear the status fields here ? */
  }

  for (n = 0; n < sc->nframes; n++) {
    off = IE_RFRAME_LAST(sc->rframes, n);
    val = sc->ie_bus_read16(sc, off);
    if ((n == sc->rftail) ^ ((val & (IE_FD_EOL|IE_FD_SUSP)) != 0)) {
      /* `rftail' and EOL flag out of sync */
      printf("%s: rx frame list out of sync at %d\n",
             sc->arpcom.ac_if.if_name, n);
      return (1);
    }
  }

  return (0);
}


/*
 * Read frame NUM from unit UNIT (pre-cached as IE).
 *
 * This routine reads the RFD at NUM, and copies in the buffers from the list
 * of RBD, then rotates the RBD list so that the receiver doesn't start
 * complaining.  Trailers are DROPPED---there's no point in wasting time
 * on confusing code to deal with them.  Hopefully, this machine will
 * never ARP for trailers anyway.
 */
static int
ie_readframe(struct ie_softc *sc, int num) /* frame number to read */
{
  struct ether_header *eh;
  struct mbuf         *m;
  u_int16_t           bstart, bend;
  int                 pktlen;

  if (i82586_get_rbd_list(sc, &bstart, &bend, &pktlen) == 0) {
    sc->arpcom.ac_if.if_ierrors++;
    return (1);
  }

  m = ieget(sc, bstart, pktlen);
  i82586_release_rbd_list(sc, bstart, bend);

  if (m == 0) {
    sc->arpcom.ac_if.if_ierrors++;
    return (0);
  }

  /*
   * Remove the mac header. This is different from the NetBSD
   * stack.
   */
  eh = mtod(m, struct ether_header *);
  m->m_data += sizeof (struct ether_header);
  m->m_len -= sizeof (struct ether_header);
  m->m_pkthdr.len -= sizeof (struct ether_header);

#if I82586_DEBUG
  if (sc->sc_debug & IED_READFRAME) {

    printf("%s: frame from ether %s type 0x%x len %d\n",
           sc->arpcom.ac_if.if_name,
           ether_sprintf(eh->ether_shost),
           (u_int)ntohs(eh->ether_type),
           pktlen);
  }
#endif

#if NBPFILTER > 0
  /* Check for a BPF filter; if so, hand it up. */
  if (sc->arpcom.ac_if.if_bpf != 0)
    /* Pass it up. */
    bpf_mtap(sc->arpcom.ac_if.if_bpf, m);
#endif /* NBPFILTER > 0 */

  /*
   * Finally pass this packet up to higher layers.
   */
  ether_input (&sc->arpcom.ac_if, eh, m);
  sc->arpcom.ac_if.if_ipackets++;
  
#if I82586_DEBUG
  I82586_TRACE(sc, I82586_RX_OK, sc->arpcom.ac_if.if_ipackets);
#endif

  return (0);
}

/*
 * Start transmission on an interface.
 */
void
i82586_start(struct ifnet *ifp)
{
  struct ie_softc *sc = ifp->if_softc;
  
  if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
    return;
  
#if I82586_DEBUG
  I82586_TRACE(sc, I82586_TX_REQ, sc->xmit_busy);
#endif
  
  rtems_event_send (sc->tx_task, i82586_TX_EVENT);
}

static void
i82586_tx_task(void *arg)
{
  struct ie_softc *sc = arg;
  rtems_event_set events;

  for (;;) {
    rtems_bsdnet_event_receive (i82586_TX_EVENT,
                                RTEMS_WAIT | RTEMS_EVENT_ANY,
                                0, &events);
    
#if I82586_DEBUG
    I82586_TRACE(sc, I82586_TX_EVT, sc->xmit_busy);
    
    if (sc->sc_debug)
      printf ("%s: =======\n", sc->arpcom.ac_if.if_name);
#endif

    i82586_start_tx(sc);
  }
}

static void
i82586_start_tx(struct ie_softc *sc)
{
  struct ifnet *ifp = &sc->arpcom.ac_if;
  struct mbuf *m0, *m;
  int  buffer, head, xbase;
  u_short  len;
  int  s;
  
#if I82586_DEBUG
  I82586_TRACE(sc, I82586_START_TX, sc->xmit_busy);
#endif
  
  if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
  {
#if I82586_DEBUG
    I82586_TRACE(sc, I82586_TX_ACTIVE, ifp->if_snd.ifq_len);
#endif
    return;
  }
  
  for (;;) {
    if (sc->xmit_busy == NTXBUF) {
      ifp->if_flags |= IFF_OACTIVE;
      break;
    }

    head = sc->xchead;
    xbase = sc->xbds;

    IF_DEQUEUE(&ifp->if_snd, m0);
    if (m0 == 0)
      break;

    /* We need to use m->m_pkthdr.len, so require the header */
    if ((m0->m_flags & M_PKTHDR) == 0)
      panic("i82586_start: no header mbuf");

#if NBPFILTER > 0
    /* Tap off here if there is a BPF listener. */
    if (ifp->if_bpf)
      bpf_mtap(ifp->if_bpf, m0);
#endif

#if I82586_DEBUG
    if (sc->sc_debug & IED_ENQ)
      printf("%s: fill buffer %d\n", sc->arpcom.ac_if.if_name,
             sc->xchead);
#endif

    if (m0->m_pkthdr.len > IE_TBUF_SIZE)
      printf("%s: tbuf overflow\n", sc->arpcom.ac_if.if_name);

    buffer = IE_XBUF_ADDR(sc, head);
    for (m = m0; m != 0; m = m->m_next) {
      (sc->memcopyout)(sc, mtod(m,caddr_t), buffer, m->m_len);
      buffer += m->m_len;
    }

    len = max(m0->m_pkthdr.len, ETHER_MIN_LEN);
    m_freem(m0);

    /*
     * Setup the transmit buffer descriptor here, while we
     * know the packet's length.
     */
    sc->ie_bus_write16(sc, IE_XBD_FLAGS(xbase, head),
                       len | IE_TBD_EOL);
    sc->ie_bus_write16(sc, IE_XBD_NEXT(xbase, head), 0xffff);
    sc->ie_bus_write24(sc, IE_XBD_BUF(xbase, head),
                       IE_XBUF_ADDR(sc, head));

    if (++head == NTXBUF)
      head = 0;
    sc->xchead = head;

#if I82586_DEBUG
    I82586_TRACE(sc, I82586_TX_START, sc->xmit_busy);
#endif
      
    s = splnet();
    /* Start the first packet transmitting. */
    if (sc->xmit_busy == 0)
      iexmit(sc);

    sc->xmit_busy++;
      
    splx(s);
  }
}

/*
 * Probe IE's ram setup   [ Move all this into MD front-end!? ]
 * Use only if SCP and ISCP represent offsets into shared ram space.
 */
int
i82586_proberam(struct ie_softc *sc)
{
  int result, off;

  /* Put in 16-bit mode */
  off = IE_SCP_BUS_USE(sc->scp);
  sc->ie_bus_write16(sc, off, 0);
  IE_BUS_BARRIER(sc, off, 2, BUS_SPACE_BARRIER_WRITE);

  /* Set the ISCP `busy' bit */
  off = IE_ISCP_BUSY(sc->iscp);
  sc->ie_bus_write16(sc, off, 1);
  IE_BUS_BARRIER(sc, off, 2, BUS_SPACE_BARRIER_WRITE);

  if (sc->hwreset)
    (sc->hwreset)(sc, CHIP_PROBE);

  (sc->chan_attn) (sc, CHIP_PROBE);

  delay(100);    /* wait a while... */

  /* Read back the ISCP `busy' bit; it should be clear by now */
  off = IE_ISCP_BUSY(sc->iscp);
  IE_BUS_BARRIER(sc, off, 2, BUS_SPACE_BARRIER_READ);
  result = sc->ie_bus_read16(sc, off) == 0;

  /* Acknowledge any interrupts we may have caused. */
  ie_ack(sc, IE_ST_WHENCE);

  return (result);
}

void
i82586_reset(struct ie_softc *sc, int hard)
{
  int s = splnet();

  if (hard)
    printf("%s: reset\n", sc->arpcom.ac_if.if_name);

  /* Clear OACTIVE in case we're called from watchdog (frozen xmit). */
  sc->arpcom.ac_if.if_timer = 0;
  sc->arpcom.ac_if.if_flags &= ~IFF_OACTIVE;

  /*
   * Stop i82586 dead in its tracks.
   */
  if (i82586_start_cmd(sc, IE_RUC_ABORT | IE_CUC_ABORT, 0, 0, 0))
    printf("%s: abort commands timed out\n", sc->arpcom.ac_if.if_name);

  /*
   * This can really slow down the i82586_reset() on some cards, but it's
   * necessary to unwedge other ones (eg, the Sun VME ones) from certain
   * lockups.
   */
  if (hard && sc->hwreset)
    (sc->hwreset)(sc, CARD_RESET);

  delay(100);
  ie_ack(sc, IE_ST_WHENCE);

  if ((sc->arpcom.ac_if.if_flags & IFF_UP) != 0) {
    i82586_init(&sc->arpcom.ac_if);
  }

  splx(s);
}

static void
setup_simple_command(struct ie_softc *sc, int cmd, int cmdbuf)
{
  /* Setup a simple command */
  sc->ie_bus_write16(sc, IE_CMD_COMMON_STATUS(cmdbuf), 0);
  sc->ie_bus_write16(sc, IE_CMD_COMMON_CMD(cmdbuf), cmd | IE_CMD_LAST);
  sc->ie_bus_write16(sc, IE_CMD_COMMON_LINK(cmdbuf), 0xffff);

  /* Assign the command buffer to the SCB command list */
  sc->ie_bus_write16(sc, IE_SCB_CMDLST(sc->scb), cmdbuf);
}

/*
 * Run the time-domain reflectometer.
 */
static void
ie_run_tdr(struct ie_softc *sc, int cmd)
{
  int result;

  setup_simple_command(sc, IE_CMD_TDR, cmd);
  sc->ie_bus_write16(sc, IE_CMD_TDR_TIME(cmd), 0);

  if (i82586_start_cmd(sc, IE_CUC_START, cmd, IE_STAT_COMPL, 0) ||
      (sc->ie_bus_read16(sc, IE_CMD_COMMON_STATUS(cmd)) & IE_STAT_OK) == 0)
    result = 0x10000; /* XXX */
  else
    result = sc->ie_bus_read16(sc, IE_CMD_TDR_TIME(cmd));

  /* Squash any pending interrupts */
  ie_ack(sc, IE_ST_WHENCE);

  if (result & IE_TDR_SUCCESS)
    return;

  if (result & 0x10000)
    printf("%s: TDR command failed\n", sc->arpcom.ac_if.if_name);
  else if (result & IE_TDR_XCVR)
    printf("%s: transceiver problem\n", sc->arpcom.ac_if.if_name);
  else if (result & IE_TDR_OPEN)
    printf("%s: TDR detected incorrect termination %d clocks away\n",
           sc->arpcom.ac_if.if_name, result & IE_TDR_TIME);
  else if (result & IE_TDR_SHORT)
    printf("%s: TDR detected a short circuit %d clocks away\n",
           sc->arpcom.ac_if.if_name, result & IE_TDR_TIME);
  else
    printf("%s: TDR returned unknown status 0x%x\n",
           sc->arpcom.ac_if.if_name, result);
}


/*
 * i82586_setup_bufs: set up the buffers
 *
 * We have a block of KVA at sc->buf_area which is of size sc->buf_area_sz.
 * this is to be used for the buffers.  The chip indexs its control data
 * structures with 16 bit offsets, and it indexes actual buffers with
 * 24 bit addresses.   So we should allocate control buffers first so that
 * we don't overflow the 16 bit offset field.   The number of transmit
 * buffers is fixed at compile time.
 *
 */
static void
i82586_setup_bufs(struct ie_softc *sc)
{
  int  ptr = sc->buf_area;  /* memory pool */
  int     n, r;

  /*
   * step 0: zero memory and figure out how many recv buffers and
   * frames we can have.
   */
  ptr = (ptr + 3) & ~3;  /* set alignment and stick with it */


  /*
   *  step 1: lay out data structures in the shared-memory area
   */

  /* The no-op commands; used if "nop-chaining" is in effect */
  sc->nop_cmds = ptr;
  ptr += NTXBUF * IE_CMD_NOP_SZ;

  /* The transmit commands */
  sc->xmit_cmds = ptr;
  ptr += NTXBUF * IE_CMD_XMIT_SZ;

  /* The transmit buffers descriptors */
  sc->xbds = ptr;
  ptr += NTXBUF * IE_XBD_SZ;

  /* The transmit buffers */
  sc->xbufs = ptr;
  ptr += NTXBUF * IE_TBUF_SIZE;

  ptr = (ptr + 3) & ~3;    /* re-align.. just in case */

  /* Compute free space for RECV stuff */
  n = sc->buf_area_sz - (ptr - sc->buf_area);

  /* Compute size of one RECV frame */
  r = IE_RFRAME_SZ + ((IE_RBD_SZ + IE_RBUF_SIZE) * B_PER_F);

  sc->nframes = n / r;

  if (sc->nframes <= 0)
    panic("ie: bogus buffer calc\n");

  sc->nrxbuf = sc->nframes * B_PER_F;

  /* The receice frame descriptors */
  sc->rframes = ptr;
  ptr += sc->nframes * IE_RFRAME_SZ;

  /* The receive buffer descriptors */
  sc->rbds = ptr;
  ptr += sc->nrxbuf * IE_RBD_SZ;

  /* The receive buffers */
  sc->rbufs = ptr;
  ptr += sc->nrxbuf * IE_RBUF_SIZE;

#if I82586_DEBUG
  printf("%s: %d frames %d bufs\n", sc->arpcom.ac_if.if_name, sc->nframes,
         sc->nrxbuf);
#endif

  /*
   * step 2: link together the recv frames and set EOL on last one
   */
  for (n = 0; n < sc->nframes; n++) {
    int m = (n == sc->nframes - 1) ? 0 : n + 1;

    /* Clear status */
    sc->ie_bus_write16(sc, IE_RFRAME_STATUS(sc->rframes,n), 0);

    /* RBD link = NULL */
    sc->ie_bus_write16(sc, IE_RFRAME_BUFDESC(sc->rframes,n),
                       0xffff);

    /* Make a circular list */
    sc->ie_bus_write16(sc, IE_RFRAME_NEXT(sc->rframes,n),
                       IE_RFRAME_ADDR(sc->rframes,m));

    /* Mark last as EOL */