path: root/c/src/libchip/network/cs8900.c

/*
  ------------------------------------------------------------------------
  $Id$
  ------------------------------------------------------------------------
  
  My Right Boot, a boot ROM for embedded hardware.
 
  Copyright Cybertec Pty Ltd, 2000
  All rights reserved Cybertec Pty Ltd, 2000
  
  COPYRIGHT (c) 1989-1998.
  On-Line Applications Research Corporation (OAR).
  Copyright assigned to U.S. Government, 1994.

  The license and distribution terms for this file may be
  found in the file LICENSE in this distribution or at
  http://www.OARcorp.com/rtems/license.html.

  ------------------------------------------------------------------------

  CS8900 net boot driver.

*/

#include <sys/errno.h>
#include <string.h>
#include <stdio.h>

/* #include <target.h>
  chris explain what this is to contain and provide a default one */
#include "cs8900.h"

/***********************************************************
 ***********************************************************
           BEGIN SECTION OF DEFAULT DEFINES
 ***********************************************************
 ***********************************************************/

/*
 * Number of devices supported by this driver
 */
#ifndef CS8900_DEVICES
#define CS8900_DEVICES 1
#endif

/*
 *  This variable really should come from a per device configuration
 *  table so the base can vary by adapter.
 */

#ifndef CS8900_IO_BASE 
extern unsigned int bsp_cs8900_io_base;
#define CS8900_IO_BASE bsp_cs8900_io_base
#endif

/*
 *  This variable really should come from a per device configuration
 *  table so the base can vary by adapter.
 */

#ifndef CS8900_MEMORY_BASE 
extern unsigned int bsp_cs8900_memory_base;
#define CS8900_MEMORY_BASE bsp_cs8900_memory_base
#endif

/*
 *  This could go to a BSP provided callout.
 */
#ifndef WATCHDOG_TOGGLE
#define WATCHDOG_TOGGLE() 
#endif

/*
 *  This variable really should come from a per device configuration
 *  table so the base can vary by adapter.
 *
 *  chris this is probably not a good default  --joel
 */

#ifndef CS8900_RX_QUEUE_SIZE 
#define CS8900_RX_QUEUE_SIZE 1
#endif

/***********************************************************
 ***********************************************************
              END SECTION OF DEFAULT DEFINES
 ***********************************************************
 ***********************************************************/

/*
 * We expect to be able to read a complete packet into an mbuf.
 */

#if (MCLBYTES < 1520)
#error "CS8900 Driver must have MCLBYTES >= 1520"
#endif

/*
 * Task event usage.
 */

#define CS8900_RX_OK_EVENT    RTEMS_EVENT_1
#define CS8900_TX_START_EVENT RTEMS_EVENT_1
#define CS8900_TX_OK_EVENT    RTEMS_EVENT_2
#define CS8900_TX_WAIT_EVENT  RTEMS_EVENT_3

/*
 * Our local data.
 */

static cs8900_device cs8900[CS8900_DEVICES];

/*
 * IO Packet Page inteface.
 */

static inline unsigned short
io_pp_get_reg_16 (int dev, unsigned short reg)
{
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PACKET_PAGE_PTR,
                     0x3000 | CS8900_PPP_AUTO_INCREMENT | reg);
  return cs8900_io_get_reg (dev, CS8900_IO_BASE + CS8900_IO_PP_DATA_PORT0);
}

static inline unsigned long
io_pp_get_reg_32 (int dev, unsigned short reg)
{
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PACKET_PAGE_PTR,
                     0x3000 | CS8900_PPP_AUTO_INCREMENT | reg);
  return ((cs8900_io_get_reg (dev, CS8900_IO_BASE + CS8900_IO_PP_DATA_PORT0) << 16) |
          cs8900_io_get_reg (dev, CS8900_IO_BASE + CS8900_IO_PP_DATA_PORT1));
}

static inline void
io_pp_set_reg_16 (int dev, unsigned short reg, unsigned short data)
{
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PACKET_PAGE_PTR,
                     0x3000 | CS8900_PPP_AUTO_INCREMENT | reg);
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PP_DATA_PORT0, data);
}

static inline void
io_pp_set_reg_32 (int dev, unsigned short reg, unsigned long data)
{
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PACKET_PAGE_PTR,
                     0x3000 | CS8900_PPP_AUTO_INCREMENT | reg);
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PP_DATA_PORT0, data >> 16);
  cs8900_io_set_reg (dev, CS8900_IO_BASE + CS8900_IO_PP_DATA_PORT1, data);
}

static inline void
io_pp_bit_set_reg_16 (int dev, unsigned short reg, unsigned short mask)
{
  io_pp_set_reg_16 (dev, reg, io_pp_get_reg_16 (dev, reg) | mask);
}

static inline void
io_pp_bit_clear_reg_16 (int dev, unsigned short reg, unsigned short mask)
{
  io_pp_set_reg_16 (dev, reg, io_pp_get_reg_16 (dev, reg) & ~mask);
}

/*
 * Memory Mapped Packet Page interface.
 */

static inline unsigned short
mem_pp_get_reg (int dev, unsigned short reg)
{
  return cs8900_mem_get_reg (dev, CS8900_MEMORY_BASE + reg);
}

static inline void
mem_pp_set_reg (int dev, unsigned short reg, unsigned short data)
{
  cs8900_mem_set_reg (dev, CS8900_MEMORY_BASE + reg, data);
}

static inline void
mem_pp_bit_set_reg (int dev, unsigned short reg, unsigned short mask)
{
  mem_pp_set_reg (dev, reg, mem_pp_get_reg (dev, reg) | mask);
}

static inline void
mem_pp_bit_clear_reg (int dev, unsigned short reg, unsigned short mask)
{
  mem_pp_set_reg (dev, reg, mem_pp_get_reg (dev, reg) & ~mask);
}

/*
 * Trace defines and control structures.
 */
 
#define CS8900_T_INT         (0)
#define CS8900_T_RX_OK       (1)
#define CS8900_T_RX_DROPPED  (2)
#define CS8900_T_NO_MBUF     (3)
#define CS8900_T_NO_CLUSTERS (4)
#define CS8900_T_RX_BEGIN    (5)
#define CS8900_T_RX_END      (6)

#if CS8900_TRACE

static const char *cs8900_trace_labels[] =
{
  "int",
  "rx ok",
  "rx dropped",
  "no mbuf",
  "no clusters",
  "rx begin",
  "rx end"
};

/*
 * Assumes a micro-second timer such as the Coldfire.
 */

rtems_unsigned32 rtems_read_timer ();

static inline void
cs8900_trace (cs8900_device *cs, unsigned short key, unsigned long var)
{
  rtems_interrupt_level level;
  
  rtems_interrupt_disable (level);
  
  if (cs->trace_in < CS8900_TRACE_SIZE)
  {
    cs->trace_key[cs->trace_in]  = key;
    cs->trace_var[cs->trace_in]  = var;
    cs->trace_time[cs->trace_in] = rtems_read_timer ();
    cs->trace_in++;
  }
  
  rtems_interrupt_enable (level);
}
#else
#define cs8900_trace(c, k, v)
#endif

/*
 * Bring the chip online.
 */

static void
cs8900_hardware_init (cs8900_device *cs)
{
  unsigned long  prod_id;
  unsigned short status;
  int            dev = cs->dev;

  /*
   * Do nothing while the device is calibrating and checking the EEPROM.
   * We must wait 20msecs.
   */
  
  io_pp_bit_set_reg_16 (dev, CS8900_PP_SelfCTL, CS8900_SELF_CTRL_RESET);

  rtems_task_wake_after (TOD_MILLISECONDS_TO_TICKS (20));
  
  status = io_pp_get_reg_16 (dev, CS8900_PP_SelfST);
  if (status == 0) {
      printf("Reading status register again\n");
      status = io_pp_get_reg_16 (dev, CS8900_PP_SelfST);
  }
    
  if (((status & CS8900_SELF_STATUS_INITD) == 0) ||
      ((status & CS8900_SELF_STATUS_INITD) &&
       (status & CS8900_SELF_STATUS_EEPROM_PRESENT) &&
       (status & CS8900_SELF_STATUS_SIBUST)))
  {
    printf ("CS8900: %s. Initialisation aborted.\n",
            (status & CS8900_SELF_STATUS_INITD) ?
            "EEPROM read/write failed to complete" :
            "Failed to complete to reset");      
    return;
  }
  
  /* Probe the device for its ID */

  prod_id = io_pp_get_reg_32 (dev, CS8900_PP_PROD_ID);

  if ((prod_id >> 16) != CS8900_ESIA_ID)
  {
    printf ("CS9800: Invalid EISA ID, read product code 0x%08lx\n", prod_id);
    return;
  }

  if ((prod_id & 0x000000ff) != 0)
  {
    printf ("CS9800: Unsupported product id, read product code 0x%08lx\n",
            prod_id);
    return;
  }

  printf ("CS8900 Rev %ld, %s, %s.\n",
          (prod_id >> 8) & 0x1f,
          status & CS8900_SELF_STATUS_3_3_V ? "3.3V" : "5.0V",
          status & CS8900_SELF_STATUS_EEPROM_PRESENT ?
          "EEPROM present" : "no EEPROM");

  /*
   * Switch to memory base accesses as they are faster. No indirect access.
   */
  
  io_pp_set_reg_16 (dev, CS8900_PP_MEM_BASE, CS8900_MEMORY_BASE);
  io_pp_set_reg_16 (dev, CS8900_PP_MEM_BASE + 2, (CS8900_MEMORY_BASE >> 16) & 0xf);
  
  io_pp_set_reg_16 (dev, 
                    CS8900_PP_BusCTL,
                    CS8900_BUS_CTRL_RESET_RX_DMA |
                    CS8900_BUS_CTRL_USE_SA |
                    CS8900_BUS_CTRL_MEMORY_ENABLE);
  io_pp_set_reg_16 (dev, 
                    CS8900_PP_BusCTL,
                    CS8900_BUS_CTRL_USE_SA |
                    CS8900_BUS_CTRL_MEMORY_ENABLE);

  /*
   * We are now in memory mapped mode.
   */

  /*
   * Program the Line Control register with the mode we want.
   *
   * No auto detect support at the moment. Only 10BaseT.
   */

  mem_pp_set_reg (dev, CS8900_PP_LineCFG, CS8900_LINE_CTRL_10BASET);
  
  /*
   * Ask the user for the MAC address, the program into the device.
   */

#define MACO(o) cs->arpcom.ac_enaddr[o]
  
  mem_pp_set_reg (dev, CS8900_PP_IA,
                  (((unsigned int) MACO (1)) << 8) |
                  ((unsigned int) MACO (0)));
  mem_pp_set_reg (dev, CS8900_PP_IA + 2,
                  (((unsigned int) MACO (3)) << 8) |
                  ((unsigned int) MACO (2)));
  mem_pp_set_reg (dev, CS8900_PP_IA + 4,
                  (((unsigned int) MACO (5)) << 8) |
                  ((unsigned int) MACO (4)));

  /*
   * Set the Buffer configuration.
   */

  mem_pp_set_reg (dev, CS8900_PP_BufCFG,
                  CS8900_BUFFER_CONFIG_RDY_FOR_TX |
                  CS8900_BUFFER_CONFIG_TX_UNDERRUN |
                  CS8900_BUFFER_CONFIG_TX_COL_OVF |
                  CS8900_BUFFER_CONFIG_RX_MISSED_OVF);

  /*
   * Set the Receiver configuration.
   */

  mem_pp_set_reg (dev, CS8900_PP_RxCFG,
                  CS8900_RX_CONFIG_RX_OK |
                  CS8900_RX_CONFIG_CRC_ERROR |
                  CS8900_RX_CONFIG_RUNT|
                  CS8900_RX_CONFIG_EXTRA_DATA);

  /*
   * Set the Receiver control.
   */

  mem_pp_set_reg (dev, CS8900_PP_RxCTL,
                  CS8900_RX_CTRL_RX_OK |
                  CS8900_RX_CTRL_MULTICAST |
                  CS8900_RX_CTRL_INDIVIDUAL |
                  CS8900_RX_CTRL_BROADCAST);
  
  /*
   * Set the Transmitter configuration.
   */

  mem_pp_set_reg (dev, CS8900_PP_TxCFG,
                  CS8900_TX_CONFIG_TX_OK |
                  CS8900_TX_CONFIG_OUT_OF_WINDOW |
                  CS8900_TX_CONFIG_JABBER |
                  CS8900_TX_CONFIG_16_COLLISION);

  /*
   * Attach the interrupt handler.
   */

  cs8900_attach_interrupt (dev, cs);
  
  /*
   * Program the interrupt level we require then enable interrupts.
   */

  mem_pp_set_reg (dev, CS8900_PP_INT, 0);

  mem_pp_bit_set_reg (dev, CS8900_PP_BusCTL,
                      CS8900_BUS_CTRL_ENABLE_INT);
}

rtems_isr
cs8900_interrupt (rtems_vector_number v, void *csp)
{
  cs8900_device  *cs = csp;
  int            dev = cs->dev;
  unsigned short isq = 0;
  struct mbuf    *m;
  unsigned char  *p;

  ++cs->eth_stats.interrupts;

  while (1)
  {
    isq = mem_pp_get_reg (dev, CS8900_PP_ISQ);

    cs8900_trace (cs, CS8900_T_INT, isq);

    WATCHDOG_TOGGLE ();
    
    /*
     * No more interrupts to service.
     */

    if (isq == 0)
      return;
    
    switch (isq & 0x1f)
    {
      case 0x04:

        /*
         * RxEvent.
         */

        ++cs->eth_stats.rx_interrupts;

        if (isq & CS8900_RX_EVENT_RX_OK)
        {
          m = cs->rx_ready_head;
          if (m)
          {
            cs->rx_ready_head = m->m_nextpkt;
            if (cs->rx_ready_head == 0)
              cs->rx_ready_tail = 0;
            m->m_nextpkt = 0;
            cs->rx_ready_len--;
            
            p = mtod (m, unsigned char *);
      
            m->m_pkthdr.len = cs8900_get_data_block (dev, p);

            if (cs->rx_loaded_tail == 0)
              cs->rx_loaded_head = m;
            else
              cs->rx_loaded_tail->m_nextpkt = m;
            cs->rx_loaded_tail = m;
            cs->rx_loaded_len++;

            if (cs->rx_loaded_len == 1)
            {
              cs8900_trace (cs, CS8900_T_RX_OK, cs->rx_loaded_len); 
              rtems_event_send (cs->rx_task, CS8900_RX_OK_EVENT);
            }
          }
          else
          {
            ++cs->eth_stats.rx_dropped;
            
            cs8900_trace (cs, CS8900_T_RX_DROPPED, cs->rx_loaded_len);      

            if (cs->rx_loaded_len == 0)
              rtems_event_send (cs->rx_task, CS8900_RX_OK_EVENT);
          }
        }
        else
        {
          if (isq & CS8900_RX_EVENT_CRC_ERROR)
            ++cs->eth_stats.rx_crc_errors;

          if (isq & CS8900_RX_EVENT_RUNT)
            ++cs->eth_stats.rx_runt_errors;
          
          if (isq & CS8900_RX_EVENT_EXTRA_DATA)
            ++cs->eth_stats.rx_oversize_errors;
        }
        break;

      case 0x08:
        
        /*
         * TxEvent.
         */

        ++cs->eth_stats.tx_interrupts;

        if (cs->tx_active)
        {
          if (isq & CS8900_TX_EVENT_TX_OK)
            ++cs->eth_stats.tx_ok;

          cs->tx_active = 0;
        
          rtems_event_send (cs->tx_task, CS8900_TX_OK_EVENT);
        }
        break;

      case 0x0c:
        
        /*
         * BufEvent.
         */
        
        if (isq & CS8900_BUFFER_EVENT_RDY_FOR_TX)
        {
          if (cs->tx_active)
          {
            ++cs->eth_stats.tx_rdy4tx;
            rtems_event_send (cs->tx_task, CS8900_TX_WAIT_EVENT);
          }
        }
        else if (isq & CS8900_BUFFER_EVENT_TX_UNDERRUN)
        {
          ++cs->eth_stats.tx_underrun_errors;
          if (cs->tx_active)
            rtems_event_send (cs->tx_task, CS8900_TX_OK_EVENT);
        }
        else if (isq & CS8900_BUFFER_EVENT_SW_INT)
        {
          ++cs->eth_stats.int_swint_res;
        }
        break;

      case 0x10:
        
        /*
         * RxMiss.
         */
        
        cs->eth_stats.rx_missed_errors +=
          mem_pp_get_reg (dev, CS8900_PP_RxMISS) >> 6;
        break;

      case 0x12:
        
        /*
         * TxCol.
         */

        cs->eth_stats.tx_collisions +=
          mem_pp_get_reg (dev, CS8900_PP_TxCol) >> 6;
        break;

      default:
        break;
    }
  }
  
}

int
cs8900_link_active (int dev)
{
  return ((mem_pp_get_reg (dev, CS8900_PP_LineST) & CS8900_LINE_STATUS_LINK_OK) ?
          1 : 0);
}

static inline void
cs8900_rx_refill_queue (cs8900_device *cs)
{
  struct ifnet          *ifp = &cs->arpcom.ac_if;
  struct mbuf           *m;
  rtems_interrupt_level level;
  
  /*
   * Hold a single queue of mbuf's at the interface. This
   * will lower the latency of the driver.
   */

  while (cs->rx_ready_len < CS8900_RX_QUEUE_SIZE)
  {
    MGETHDR (m, M_DONTWAIT, MT_DATA);
    
    if (!m)
    {
      ++cs->eth_stats.rx_no_mbufs;
      cs8900_trace (cs, CS8900_T_NO_MBUF, cs->eth_stats.rx_no_mbufs);      
      return;
    }
          
    MCLGET (m, M_DONTWAIT);
    
    if (!m->m_ext.ext_buf)
    {
      ++cs->eth_stats.rx_no_clusters;
      cs8900_trace (cs, CS8900_T_NO_CLUSTERS, cs->eth_stats.rx_no_clusters);      
      m_free (m);
      return;
    }
    m->m_pkthdr.rcvif = ifp;
    m->m_nextpkt = 0;

    rtems_interrupt_disable (level);
    
    if (cs->rx_ready_tail == 0)
      cs->rx_ready_head = m;
    else
      cs->rx_ready_tail->m_nextpkt = m;
    cs->rx_ready_tail = m;
    cs->rx_ready_len++;

    rtems_interrupt_enable (level);
  }
}

static void
cs8900_rx_task (void *arg)
{
  cs8900_device         *cs = arg;
  int                   dev = cs->dev;
  struct ifnet          *ifp = &cs->arpcom.ac_if;
  rtems_event_set       events;
  struct mbuf           *m;
  struct ether_header   *eh;
  rtems_status_code     sc;
  rtems_interrupt_level level;

  /*
   * Turn the receiver and transmitter on.
   */
  
  mem_pp_bit_set_reg (dev, CS8900_PP_LineCFG,
                      CS8900_LINE_CTRL_RX_ON |
                      CS8900_LINE_CTRL_TX_ON);
  
  /*
   * Start the software interrupt watchdog.
   */
  
  rtems_interrupt_disable (level);
  mem_pp_bit_set_reg (dev, CS8900_PP_BufCFG,
                      CS8900_BUFFER_CONFIG_SW_INT);
  ++cs->eth_stats.int_swint_req;
  rtems_interrupt_enable (level);
  
  /*
   * Loop reading packets.
   */

  while (1)
  {
    cs8900_rx_refill_queue (cs);
    
    sc = rtems_bsdnet_event_receive (CS8900_RX_OK_EVENT,
                                     RTEMS_WAIT | RTEMS_EVENT_ANY,
                                     TOD_MILLISECONDS_TO_TICKS (250),
                                     &events);

    cs8900_rx_refill_queue (cs);
    
    if (sc == RTEMS_TIMEOUT)
    {
      /*
       * We need to check the interrupt hardware in the cs8900a
       * has not locked up. It seems this occurs if the ISQ
       * queue fills up.
       * To test we generate a software interrupt and watch
       * a counter go up. If the counter does not go for 2
       * software interrupts requests we flush the ISQ queue.
       */

      if ((cs->eth_stats.int_swint_req - cs->eth_stats.int_swint_res) > 1)
      {
        printf ("cs8900: int lockup, isq flush\n");

        mem_pp_bit_clear_reg (dev, CS8900_PP_BusCTL,
                              CS8900_BUS_CTRL_ENABLE_INT);
        
        while (mem_pp_get_reg (dev, CS8900_PP_ISQ) != 0);
        
        cs->eth_stats.int_swint_req = cs->eth_stats.int_swint_res = 0;
        ++cs->eth_stats.int_lockup;
        
        mem_pp_bit_set_reg (dev, CS8900_PP_BusCTL,
                            CS8900_BUS_CTRL_ENABLE_INT);
      }
      
      rtems_interrupt_disable (level);
      mem_pp_bit_set_reg (dev, CS8900_PP_BufCFG,
                          CS8900_BUFFER_CONFIG_SW_INT);
      ++cs->eth_stats.int_swint_req;
      rtems_interrupt_enable (level);
    }

    cs8900_trace (cs, CS8900_T_RX_BEGIN, cs->rx_loaded_len);
    
    while (cs->rx_loaded_len)
    {
      rtems_interrupt_disable (level);
    
      m = cs->rx_loaded_head;
      if (m)
      {
        cs->rx_loaded_head = m->m_nextpkt;
        if (cs->rx_loaded_head == 0)
          cs->rx_loaded_tail = 0;
        m->m_nextpkt = 0;
        cs->rx_loaded_len--;
        
        rtems_interrupt_enable (level);
        
        m->m_pkthdr.rcvif = ifp;
        
        cs->eth_stats.rx_bytes += m->m_pkthdr.len;
        
        m->m_len = m->m_pkthdr.len = m->m_pkthdr.len - sizeof (struct ether_header);
        
        eh = mtod (m, struct ether_header *);
        m->m_data += sizeof (struct ether_header);
      
        ++cs->eth_stats.rx_packets;
        
        ether_input (ifp, eh, m);
      }
      else
      {
        rtems_interrupt_enable (level);
      }
    }
    cs8900_trace (cs, CS8900_T_RX_END, cs->rx_loaded_len);
  }
}

static void
cs8900_tx_task (void *arg)
{
  cs8900_device     *cs = arg;
  int               dev = cs->dev;
  struct ifnet      *ifp = &cs->arpcom.ac_if;
  rtems_event_set   events;
  struct mbuf       *m;
  rtems_status_code sc;

  /*
   * Wait for the link to come up.
   */

  rtems_task_wake_after (TOD_MILLISECONDS_TO_TICKS (750));

  /*
   * Loop processing the tx queue.
   */

  while (1)
  {
    /*
     * Fetch the mbuf list from the interface's queue.
     */

    IF_DEQUEUE (&ifp->if_snd, m);

    /*
     * If something actually is present send it.
     */

    if (!m)
    {
      ifp->if_flags &= ~IFF_OACTIVE;

      rtems_bsdnet_event_receive (CS8900_TX_START_EVENT,
                                  RTEMS_WAIT | RTEMS_EVENT_ANY,
                                  RTEMS_NO_TIMEOUT,
                                  &events);
    }
    else
    {
      if (cs8900_link_active (dev))
      {
        int resending;
        
        do
        {
          unsigned short buf_status;

          resending = 0;
          
          cs->tx_active = 1;
          
          mem_pp_set_reg (dev, CS8900_PP_TxCMD,
                          CS8900_TX_CMD_STATUS_TX_START_ENTIRE |
                          CS8900_TX_CMD_STATUS_FORCE);
          mem_pp_set_reg (dev, CS8900_PP_TxLength, m->m_pkthdr.len);
          
          buf_status = mem_pp_get_reg (dev, CS8900_PP_BusST);

          /*
           * If the bid for memory in the device fails trash the
           * transmit and try again next time.
           */

          if (buf_status & CS8900_BUS_STATUS_TX_BID_ERROR)
            ++cs->eth_stats.tx_bid_errors;
          else
          {
            /*
             * If the buffer is not read enable the interrupt and then wait.
             */
            
            if ((buf_status & CS8900_BUS_STATUS_RDY_FOR_TX_NOW) == 0)
            {
              cs->eth_stats.tx_wait_for_rdy4tx++;
              sc = rtems_bsdnet_event_receive (CS8900_TX_WAIT_EVENT,
                                               RTEMS_WAIT | RTEMS_EVENT_ANY,
                                               TOD_MILLISECONDS_TO_TICKS (750),
                                               &events);
              if (sc == RTEMS_TIMEOUT)
              {
                /*
                 * For some reason the wait request has been dropped,
                 * so lets resend from the start.
                 */

                printf ("tx resend\n");
                ++cs->eth_stats.tx_resends;
                resending = 1;
              }
            }

            if (!resending)
            {
              cs8900_tx_load (dev, m);
              cs->eth_stats.tx_packets++;
              cs->eth_stats.tx_bytes += m->m_pkthdr.len;
            }
          }
        }
        while (resending);
        
        m_freem (m);
        
        do
        {
          rtems_bsdnet_event_receive (CS8900_TX_OK_EVENT,
                                      RTEMS_WAIT | RTEMS_EVENT_ANY,
                                      RTEMS_NO_TIMEOUT,
                                      &events);
        }
        while (cs->tx_active);
      }
      else
      {
        ++cs->eth_stats.tx_dropped;
        m_freem (m);
      }
    }
  }
}

static void
cs8900_start (struct ifnet *ifp)
{
  cs8900_device *cs = ifp->if_softc;

  /*
   * Tell the transmit daemon to wake up and send a packet.
   */

  ifp->if_flags |= IFF_OACTIVE;

  rtems_event_send (cs->tx_task, CS8900_TX_START_EVENT);
}

static void
cs8900_stop (cs8900_device *cs)
{
  int dev = cs->dev;

  mem_pp_bit_clear_reg (dev, CS8900_PP_LineCFG,
                        CS8900_LINE_CTRL_RX_ON |
                        CS8900_LINE_CTRL_TX_ON);
  
  mem_pp_bit_clear_reg (dev, CS8900_PP_BusCTL,
                        CS8900_BUS_CTRL_ENABLE_INT);
}

static const char *eth_statistics_labels[] =
{
  "rx packets",
  "tx packets",
  "rx bytes",
  "tx bytes",
  "rx interrupts",
  "tx interrupts",
  "rx dropped",
  "rx no mbuf",
  "rx no custers",
  "rx oversize errors",
  "rx crc errors",
  "rx runt errors",
  "rx missed errors",
  "tx ok",
  "tx collisions",
  "tx bid errors",
  "tx wait for rdy4tx",
  "tx rdy4tx",
  "tx underrun errors",
  "tx dropped",
  "tx resends",
  "int swint req",
  "int swint res",
  "int lockup",
  "interrupts"
};

static void
cs8900_stats (cs8900_device *cs)
{
  int           dev = cs->dev;
  int           i;
  int           max_label = 0;
  int           len;
  unsigned long *value = (unsigned long*) &cs->eth_stats.rx_packets;

  cs->eth_stats.rx_missed_errors +=
    mem_pp_get_reg (dev, CS8900_PP_RxMISS) >> 6;
    
  cs->eth_stats.tx_collisions +=
    mem_pp_get_reg (dev, CS8900_PP_TxCol) >> 6;
  
  printf ("Network Driver Stats for CS8900 :\n");

  for (i = 0; i < (sizeof (eth_statistics_labels) / sizeof (const char *)); i++)
  {
    len = strlen (eth_statistics_labels[i]);
    if (len > max_label)
      max_label = len;
  }

  max_label += 2;

  printf ("%*s - %10u %*s - %10u\n",
          max_label, "rx ready len", cs->rx_ready_len,
          max_label, "rx loaded len", cs->rx_loaded_len);
  
  for (i = 0;
       i < (sizeof (eth_statistics_labels) / sizeof (const char *));
       i++)
  {
    printf ("%*s - %10lu",
            max_label, eth_statistics_labels[i], value[i]);
    
    i++;
    
    if (i < (sizeof (eth_statistics_labels) / sizeof (const char *)))
      printf (" %*s - %10lu",
              max_label, eth_statistics_labels[i], value[i]);
    printf ("\n");
  }

#if CS8900_TRACE
  
  for (i = 0; i < cs->trace_in; i++)
  {
    printf ("%8ld.%03ld ", cs->trace_time[i] / 1000, cs->trace_time[i] % 1000);
    
    if (cs->trace_key[i] < sizeof (cs8900_trace_labels) / sizeof (char*))
      printf ("%s : ", cs8900_trace_labels[cs->trace_key[i]]);
    else
      printf ("unknown trace key, %d : ", cs->trace_key[i]);

    if (cs->trace_key[i] == CS8900_T_INT)
    {
      printf ("0x%04lx ", cs->trace_var[i]);
      if (cs->trace_var[i] == 0)
        printf ("end");
      else
      {
        switch (cs->trace_var[i] & 0x1f)
        {
          case 0x04:
            printf ("rx event");
            break;

          case 0x08:
            printf ("tx event");
            break;

          case 0x0c:
            printf ("buffer event");
            break;

          case 0x10:
            printf ("rx missed");
            break;

          case 0x12:
            printf ("tx collisions");
            break;

          case 0x1f:
            printf ("tx request");
            break;
          
          case 0x1e:
            printf ("tx wait 4 tx");
            break;
          
          case 0x1d:
            printf ("tx already active");
            break;
          
          default:
            printf ("unknown event");
            break;
        }
      }
    }
    else
      printf ("0x%08lx", cs->trace_var[i]);
    
    printf ("\n");
  }

  cs->trace_in = 0;
  
#endif
}

static void
cs8900_init (void *arg)
{
  cs8900_device *cs  = arg;
  int           dev  = cs->dev;
  struct ifnet  *ifp = &cs->arpcom.ac_if;

  if (cs->rx_task == 0)
  {

    /*
     * Set up the hardware.
     */
    
    cs8900_hardware_init (cs);

    /*
     * Start driver task. We have only one task.
     */
    
    cs->rx_task = rtems_bsdnet_newproc ("CSr0", 4096, cs8900_rx_task, cs);
    cs->tx_task = rtems_bsdnet_newproc ("CSt0", 4096, cs8900_tx_task, cs);
  }

#ifdef todo
  /*
   * Set flags appropriately
   */
  if (ifp->if_flags & IFF_PROMISC)
  else
#endif
  
  /*
   * Tell the world that we're running.
   */
  
  ifp->if_flags |= IFF_RUNNING;

  /*
   * Set the Line Control to bring the receive and transmitter online. 
   */

  mem_pp_bit_set_reg (dev, CS8900_PP_LineCFG,
                      CS8900_LINE_CTRL_RX_ON |
                      CS8900_LINE_CTRL_TX_ON);

  mem_pp_bit_set_reg (dev, CS8900_PP_BusCTL,
                      CS8900_BUS_CTRL_ENABLE_INT);
}

static int
cs8900_ioctl (struct ifnet *ifp, int cmd, caddr_t data)
{
  cs8900_device *cs = ifp->if_softc;
  int           error = 0;

  switch (cmd)
  {
    case SIOCGIFADDR:
    case SIOCSIFADDR:
      
      error = ether_ioctl (ifp, cmd, data);
      break;

    case SIOCSIFFLAGS:
      
      switch (ifp->if_flags & (IFF_UP | IFF_RUNNING))
      {
        case IFF_RUNNING:
          
          cs8900_stop (cs);
          break;

        case IFF_UP:
          
          cs8900_init (cs);
          break;

        case IFF_UP | IFF_RUNNING:
          
          cs8900_stop (cs);
          cs8900_init (cs);
          break;

        default:
          break;
      }
      break;

    case SIO_RTEMS_SHOW_STATS:
      
      cs8900_stats (cs);
      break;

      /* FIXME: Multicast commands must be added here.  */

    default:
      error = EINVAL;
      break;
  }

  return error;
}

int
cs8900_driver_attach (struct rtems_bsdnet_ifconfig *config, int attaching)
{
  cs8900_device *cs;
  struct ifnet  *ifp;
  int           mtu;
  int           unit;
  char          *name;

  /*
    * Parse driver name
   */
  
  if ((unit = rtems_bsdnet_parse_driver_name (config, &name)) < 0)
    return 0;
  
  /*
   * Is driver free?
   */
  
  if (unit >= CS8900_DEVICES)
  {
    printf ("Bad CS8900 unit number for device `%s'.\n", config->name);
    return 0;
  }
  
  cs      = &cs8900[unit];
  cs->dev = unit;
  ifp     = &cs->arpcom.ac_if;

  if (attaching)
  {
    if (ifp->if_softc)
    {
      printf ("Driver `%s' already in use.\n", config->name);
      return 0;
    }

    /*
     * Process options
     */
    
    if (config->hardware_address)
      memcpy (cs->arpcom.ac_enaddr, config->hardware_address, ETHER_ADDR_LEN);
    else
      cs8900_get_mac_addr (unit, cs->arpcom.ac_enaddr);
  
    if (config->mtu)
      mtu = config->mtu;
    else
      mtu = ETHERMTU;
    
    cs->accept_bcast = !config->ignore_broadcast;
    
    /*
     * Set up network interface values.
     */
    
    ifp->if_softc  = cs;
    ifp->if_unit   = unit;
    ifp->if_name   = name;
    ifp->if_mtu    = mtu;
    ifp->if_init   = cs8900_init;
    ifp->if_ioctl  = cs8900_ioctl;
    ifp->if_start  = cs8900_start;
    ifp->if_output = ether_output;
    ifp->if_flags  = IFF_BROADCAST | IFF_SIMPLEX;
    
    if (ifp->if_snd.ifq_maxlen == 0)
      ifp->if_snd.ifq_maxlen = ifqmaxlen;
    
    /*
     * Attach the interface to the stack.
     */
    
    if_attach (ifp);
    ether_ifattach (ifp);
  }
  else
  {
    if (!ifp->if_softc)
    {
      printf ("Driver `%s' not found.\n", config->name);
      return 0;
    }

    cs8900_stop (cs);
    cs8900_detach_interrupt (unit);
  }
  
  return 1;
  
}