elnk.c

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

static void no_op(const rtems_irq_connect_data* irq)
{
   return;
}




static int elnkIsOn(const rtems_irq_connect_data* irq)
{
  return BSP_irq_enabled_at_i8259s (irq->name);
}






static void 
elnk_start_txchain( struct elnk_softc *sc, struct TXMD *chainhead )
{
   xl_wait(sc);
   CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_STALL);

   /* save the address of the TX list */
   sc->last_txchain_head = chainhead;
   sc->tx_idle = 0;

   xl_wait(sc);

   CSR_WRITE_4(sc, XL_DOWNLIST_PTR, phys_to_bus( sc->last_txchain_head ));
   CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_UNSTALL);
}





/*
 * ELNK interrupt handler
 */
static rtems_isr
elnk_interrupt_handler ( struct elnk_softc *sc )
{
   struct ifnet		*ifp = &sc->arpcom.ac_if;
   u_int16_t		status;

   while( ((status = CSR_READ_2(sc, XL_STATUS)) & XL_INTRS) && status != 0xFFFF)
   {
      sc->xl_stats.device_interrupts++;

      CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ACK | (status & XL_INTRS));

#if 0
      printk("etherlink : unit elnk%d intstatus %04x\n", sc->xl_unit, status  );
#endif

      if (status & XL_STAT_UP_COMPLETE) 
      {
#if 0
         printk("etherlink : unit elnk%d rx\n", sc->xl_unit );
#endif
         /* received packets */
         rtems_event_send(rxDaemonTid, sc->ioevent);
      }

      if( (status & XL_STAT_DOWN_COMPLETE) || (status & XL_STAT_TX_COMPLETE) )
      {
         /* all packets uploaded to the device */
         struct TXMD *chaintailmd = NULL;


         if( status & XL_STAT_TX_COMPLETE )
         {
            /* if we got a tx complete error, count it, then reset the
               transmitter.  Consider the entire chain lost.. */

            ifp->if_oerrors++;
            sc->xl_stats.txcomplete_ints++;

            printk("etherlink : unit elnk%d transmit error\n", sc->xl_unit );

            /* reset, re-enable fifo */

            xl_wait(sc);
            CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_DISABLE);

            xl_wait(sc);
            CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_RESET | 1 );

            xl_wait(sc);
            CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_ENABLE);

            xl_wait(sc);
         }


         /* send the chain head to the tx task which will recover the
            whole chain */
         rtems_message_queue_send( chainRecoveryQueue, &sc->last_txchain_head, sizeof(struct TXMD *));


         /* set up the next chain */
         if( sc->last_txchain_head->chainptr )
         {
            /* check the head of the chain of packets we just finished,
             * if != 0, either this is a chain of 2 or more packets or
             * its a single packet chain and another chain is ready to
             * send.
             */
            if( (int)sc->last_txchain_head->chainptr == -1 )
            {
               /* 
               ** single packet was sent so no indirection to the last
               ** entry in the chain.  since chainptr is != 0, then
               ** another chain is ready starting from the packet AFTER
               ** the chain we just finished. - in this case the last
               ** chain's head == its tail
               */
               chaintailmd = sc->last_txchain_head;
            }
            else
            {
               /*
               ** otherwise, this is a pointer to the last packet in the
               ** chain of 2 or more packets.  If the chain's last
               ** packet's chainptr is != 0, then another chain is ready
               ** to send.
               */
               chaintailmd = sc->last_txchain_head->chainptr;
               if( !chaintailmd->chainptr ) chaintailmd = NULL;
            }
         }

         if( chaintailmd )
         {
            /* the next MD is the start of another chain */
            elnk_start_txchain(sc, chaintailmd->next_md );
         }
         else
         {
            /* otherwise nothing to send, so go idle */
            sc->tx_idle = -1;

            /* wake up the tx daemon once so we're sure this last chain
               will be freed */
            rtems_event_send( txDaemonTid, sc->ioevent );
#if 0
            printk("unit elnk%d tx done\n", sc->xl_unit );
#endif
         }
      }


      if (status & XL_STAT_ADFAIL) 
      {
         printk("etherlink : unit elnk%d Catastrophic bus failure\n", sc->xl_unit );
      }
      if (status & XL_STAT_STATSOFLOW) 
      {
         sc->xl_stats_no_timeout = 1;
         xl_stats_update(sc->stat_timer_id,sc);
         sc->xl_stats_no_timeout = 0;
      }
   }
   

#if 0
   {
      unsigned16 intstatus, intenable, indenable;

      intstatus = CSR_READ_2(sc, XL_STATUS );

      XL_SEL_WIN(5);
      intenable = CSR_READ_2(sc, XL_W5_INTR_ENB );
      indenable = CSR_READ_2(sc, XL_W5_STAT_ENB );
      XL_SEL_WIN(7);
      printk("etherlink : unit elnk%d istat %04x, ien %04x, ind %04x\n", sc->xl_unit, intstatus, intenable, indenable  );
   }
#endif
}





static rtems_isr
elnk_interrupt_handler_entry()
{
   int i;

   /*
   ** Check all the initialized units for interrupt service
   */

   for(i=0; i< NUM_UNITS; i++ )
   {
      if( elnk_softc[i].ioaddr )
         elnk_interrupt_handler( &elnk_softc[i] );
   }
}











/*
 * Initialize the ethernet hardware
 */
static void
elnk_initialize_hardware (struct elnk_softc *sc)
{
   unsigned char *cp;
   int i, j, rxsize, txsize, ringsize;

   /*
    * Init RX ring
    */
   cp = (unsigned char *)malloc( (ringsize = ((rxsize = (sc->numRxbuffers * sizeof(struct RXMD))) + 
                                              (txsize = (sc->numTxbuffers * sizeof(struct TXMD)))) ) +
                                 + CPU_CACHE_ALIGNMENT_FOR_BUFFER);
   sc->bufferBase = cp;
   cp += (CPU_CACHE_ALIGNMENT_FOR_BUFFER - (int)cp) & (CPU_CACHE_ALIGNMENT_FOR_BUFFER - 1);
#if defined(__i386__)
#ifdef PCI_BRIDGE_DOES_NOT_ENSURE_CACHE_COHERENCY_FOR_DMA 
   if (_CPU_is_paging_enabled())
      _CPU_change_memory_mapping_attribute
         (NULL, cp, ringsize, PTE_CACHE_DISABLE | PTE_WRITABLE);
#endif
#endif
   sc->ringBase = cp;

   /* build tx and rx rings */

   sc->rx_ring = (struct RXMD *)sc->ringBase;
   sc->tx_ring = (struct TXMD *)&sc->ringBase[ rxsize ];

   {
      struct mbuf    *m;
      struct RXMD    *nxtmd;
      /* 
       * The rx ring is easy as its just an array of RXMD structs.  New
       * mbuf entries are allocated from the stack whenever the rx
       * daemon forwards an incoming packet into it.  Here, we
       * pre-allocate the rx mbufs for the rx ring entries.
       */
      for(i=0 ; i<sc->numRxbuffers; i++)
      {
         if( ((unsigned32)&sc->rx_ring[i] & 0x7) )
         {
            rtems_panic ("etherlink : unit elnk%d rx ring entry %d not aligned to 8 bytes\n", sc->xl_unit, i );
         }
      
         /* allocate an mbuf for each receive descriptor */
         MGETHDR (m, M_WAIT, MT_DATA);
         MCLGET (m, M_WAIT);
         m->m_pkthdr.rcvif = &sc->arpcom.ac_if;

         if( i == sc->numRxbuffers-1 )
            nxtmd = &sc->rx_ring[0];
         else
            nxtmd = &sc->rx_ring[i+1];

         sc->rx_ring[i].next_md = nxtmd;
         sc->rx_ring[i].mbuf = m;

         st_le32( &sc->rx_ring[i].status, 0);
         st_le32( &sc->rx_ring[i].next, (unsigned32)phys_to_bus( nxtmd ));
         st_le32( &sc->rx_ring[i].addr, (unsigned32)phys_to_bus( mtod(m, void *) ));
         st_le32( &sc->rx_ring[i].length, XL_LAST_FRAG | XL_PACKET_SIZE );
      }
      sc->curr_rx_md = &sc->rx_ring[0];
   }


   {
      struct TXMD *thismd, *nxtmd;
      /* 
       * The tx ring is more complex. Each MD has an array of fragment
       * descriptors that are loaded from each packet as they arrive
       * from the stack.  Each packet gets one ring entry, this allows
       * the lanboard to efficiently assemble the piecemeal packets into
       * a contiguous unit at transmit time, rather than spending
       * cputime concatenating them first.  Although the next_md fields
       * form a ring, the DPD next is filled only when packets are added
       * to the tx chain, thus last entry of a series of packets has the
       * requisite dpd->next value == 0 to terminate the dma.  mbuf
       * holds the packet info so it can be freed once the packet has
       * been sent.  chainptr is used to link the head & tail of a chain
       * of 2 or more packets.  A chain is formed when the tx daemon
       * gets 2 or more packets from the stack's queue in a service
       * period, so higher outgoing loads are handled as efficiently as
       * possible.
       */

      for(i=0 ; i<sc->numTxbuffers; i++)
      {
         if( ((unsigned32)&sc->tx_ring[i] & 0x7) )
         {
            rtems_panic ("etherlink : unit elnk%d tx ring entry %d not aligned to 8 bytes\n", sc->xl_unit, i );
         }

         if( i == sc->numTxbuffers-1 )
            nxtmd = &sc->tx_ring[0];
         else
            nxtmd = &sc->tx_ring[i+1];

         thismd = &sc->tx_ring[i];

         thismd->next_md = nxtmd;
         thismd->chainptr = NULL;
         thismd->mbuf = NULL;

         st_le32( &thismd->status, XL_TXSTAT_DL_COMPLETE );
         st_le32( &thismd->next, 0);

         for(j=0; j< NUM_FRAGS; j++)
         {
            st_le32( &thismd->txfrags[j].addr, 0 );
            st_le32( &thismd->txfrags[j].length, 0 );
         }
      }
      sc->last_tx_md = &sc->tx_ring[0];
   }




#ifdef ELNK_DEBUG
   printk("etherlink : %02x:%02x:%02x:%02x:%02x:%02x   name 'elnk%d', io %x, int %d\n",
          sc->arpcom.ac_enaddr[0], sc->arpcom.ac_enaddr[1],
          sc->arpcom.ac_enaddr[2], sc->arpcom.ac_enaddr[3],
          sc->arpcom.ac_enaddr[4], sc->arpcom.ac_enaddr[5],
          sc->xl_unit, 
          (unsigned)sc->ioaddr, sc->irqInfo.name );
#endif


   sc->irqInfo.hdl  = (rtems_irq_hdl)elnk_interrupt_handler_entry;
   sc->irqInfo.on   = no_op;
   sc->irqInfo.off  = no_op;
   sc->irqInfo.isOn = elnkIsOn;

   if( sc->irqInfo.name != 255 )
   {
      int st;

#ifdef BSP_SHARED_HANDLER_SUPPORT
      st = BSP_install_rtems_shared_irq_handler( &sc->irqInfo );
#else
      st = BSP_install_rtems_irq_handler( &sc->irqInfo );
#endif
      if (!st)
         rtems_panic ("etherlink : unit elnk%d Interrupt name %d already in use\n", sc->xl_unit, sc->irqInfo.name );
   }
   else
   {
      printk("etherlink : unit elnk%d Interrupt not specified by device\n", sc->xl_unit );
   }
}











static void
elnk_rxDaemon (void *arg)
{
   struct elnk_softc     *sc;
   struct ether_header   *eh;
   struct mbuf           *m;
   struct RXMD           *rmd;
   unsigned int          i,len, rxstat;
   rtems_event_set       events;

   for (;;)
   {

      rtems_bsdnet_event_receive( RTEMS_ALL_EVENTS,
                                  RTEMS_WAIT|RTEMS_EVENT_ANY,
                                  RTEMS_NO_TIMEOUT,
                                  &events);

      for(;;)
      {
         for(i=0; i< NUM_UNITS; i++ )
         {
            sc = &elnk_softc[i];
            if( sc->ioaddr )
            {
               if( events & sc->ioevent )
               {
                  struct ifnet *ifp = &sc->arpcom.ac_if;

                  rmd   = sc->curr_rx_md;

                  /*
                  ** Read off all the packets we've received on this unit
                  */
                  while( (rxstat = ld_le32(&rmd->status)) )
                  {
                     if (rxstat & XL_RXSTAT_UP_ERROR) 
                     {
                        printk("unit %i up error\n", sc->xl_unit );
                        ifp->if_ierrors++;
                     }

                     if( (rxstat & XL_RXSTAT_UP_CMPLT) ) 
                     {

#if 0
                        {
                           char *pkt, *delim;
                           int  i;
                           pkt = mtod(rmd->mbuf, char *);
                           printk("unit %i rx  pkt (%08x) ", sc->xl_unit, pkt );
                           for(delim="", i=0; i < sizeof(struct ether_header)+8; i++, delim=":")
                              printk("%s%02x", delim, (char) pkt[i] );
                           printk("\n");
                        }
#endif

                        /* pass on the packet in the mbuf */
                        len = ( ld_le32(&rmd->status) & XL_RXSTAT_LENMASK);
                        m = rmd->mbuf;
                        m->m_len = m->m_pkthdr.len = len - sizeof(struct ether_header);
                        eh = mtod(m, struct ether_header *);
                        m->m_data += sizeof(struct ether_header);

                        ether_input(ifp, eh, m);

                        /* get a new mbuf */
                        MGETHDR (m, M_WAIT, MT_DATA);
                        MCLGET (m, M_WAIT);
                        m->m_pkthdr.rcvif = ifp;
                        rmd->mbuf   = m;
                        st_le32( &rmd->status, 0 );
                        st_le32( &rmd->addr, (unsigned32)phys_to_bus(mtod(m, void *)) );
                     }
                     else
                     {
                        /* some kind of packet failure */
                        printk("etherlink : unit elnk%d bad receive status -- packet dropped\n", sc->xl_unit);
                        ifp->if_ierrors++;
                     }
                     /* clear descriptor status */
                     rmd->status = 0;
      
                     rmd = rmd->next_md;
                  }

                  sc->curr_rx_md = rmd;
               }
            }
         }

         /*
         ** If more events are pending, service them befo