stellarisif.c

lm3s下lwip的udp

     *
     */
    while((iBuf + 4) <= q->len) {
      HWREG(ETH_BASE + MAC_O_DATA) = *pulBuf++;
      iBuf += 4;
    }

    /**
     * Check if leftover data in the pbuf and save it in the gather
     * buffer for the next time.
     *
     */
    while(iBuf < q->len) {
      /* Copy a byte from the pbuf into the gather buffer. */
      pucGather[iGather] = pucBuf[iBuf++];

      /* Increment the gather buffer index modulo 4. */
      iGather = ((iGather + 1) % 4);
    }
  }

  /* Send any leftover data to the FIFO. */
  HWREG(ETH_BASE + MAC_O_DATA) = ulGather;

  /* Wakeup the transmitter. */
  HWREG(ETH_BASE + MAC_O_TR) = MAC_TR_NEWTX;

  /* Dereference the pbuf from the queue. */
  pbuf_free(p);

  LINK_STATS_INC(link.xmit);

  return(ERR_OK);
}

/**
 * This function with either place the packet into the Stellaris transmit fifo,
 * or will place the packet in the interface PBUF Queue for subsequent
 * transmission when the transmitter becomes idle.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
 * @return ERR_OK if the packet could be sent
 *         an err_t value if the packet couldn't be sent
 *
 */
static err_t
low_level_output(struct netif *netif, struct pbuf *p)
{
  struct ethernetif *ethernetif = netif->state;
  SYS_ARCH_DECL_PROTECT(lev);

  /**
   * This entire function must run within a "critical section" to preserve
   * the integrity of the transmit pbuf queue.
   *
   */
  SYS_ARCH_PROTECT(lev);

  /**
   * Bump the reference count on the pbuf to prevent it from being
   * freed till we are done with it.
   *
   */
  pbuf_ref(p);

  /**
   * If the transmitter is idle, and there is nothing on the queue,
   * send the pbuf now.
   *
   */
  if(PBUF_QUEUE_EMPTY(&ethernetif->txq) &&
    ((HWREG(ETH_BASE + MAC_O_TR) & MAC_TR_NEWTX) == 0)) {
    low_level_transmit(netif, p);
  }

  /* Otherwise place the pbuf on the transmit queue. */
  else {
    /* Add to transmit packet queue */
    if(!enqueue_packet(p, &(ethernetif->txq))) {
      /* if no room on the queue, free the pbuf reference and return error. */
      pbuf_free(p);
      SYS_ARCH_UNPROTECT(lev);
      return (ERR_MEM);
    }
  }

  /* Return to prior interrupt state and return. */
  SYS_ARCH_UNPROTECT(lev);
  return ERR_OK;
}

/**
 * This function will read a single packet from the Stellaris ethernet
 * interface, if available, and return a pointer to a pbuf.  The timestamp
 * of the packet will be placed into the pbuf structure.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return pointer to pbuf packet if available, NULL otherswise.
 */
static struct pbuf *
low_level_receive(struct netif *netif)
{
  struct pbuf *p, *q;
  u16_t len;
  u32_t temp;
  int i;
  unsigned long *ptr;
#if LWIP_PTPD
  u32_t time_s, time_ns;

  /* Get the current timestamp if PTPD is enabled */
  lwIPHostGetTime(&time_s, &time_ns);
#endif


  /* Check if a packet is available, if not, return NULL packet. */
  if((HWREG(ETH_BASE + MAC_O_NP) & MAC_NP_NPR_M) == 0) {
    return(NULL);
  }

  /**
   * Obtain the size of the packet and put it into the "len" variable.
   * Note:  The length returned in the FIFO length position includes the
   * two bytes for the length + the 4 bytes for the FCS.
   *
   */
  temp = HWREG(ETH_BASE + MAC_O_DATA);
  len = temp & 0xFFFF;

  /* We allocate a pbuf chain of pbufs from the pool. */
  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);

  /* If a pbuf was allocated, read the packet into the pbuf. */
  if(p != NULL) {
    /* Place the first word into the first pbuf location. */
    *(unsigned long *)p->payload = temp;
    p->payload = (char *)(p->payload) + 4;
    p->len -= 4;

    /* Process all but the last buffer in the pbuf chain. */
    q = p;
    while(q != NULL) {
      /* Setup a byte pointer into the payload section of the pbuf. */
      ptr = q->payload;

      /**
       * Read data from FIFO into the current pbuf
       * (assume pbuf length is modulo 4)
       *
       */
      for(i = 0; i < q->len; i += 4) {
        *ptr++ = HWREG(ETH_BASE + MAC_O_DATA);
      }

      /* Link in the next pbuf in the chain. */
      q = q->next;
    }

    /* Restore the first pbuf parameters to their original values. */
    p->payload = (char *)(p->payload) - 4;
    p->len += 4;

    /* Adjust the link statistics */
    LINK_STATS_INC(link.recv);

#if LWIP_PTPD
    /* Place the timestamp in the PBUF */
    p->time_s = time_s;
    p->time_ns = time_ns;
#endif
  }

  /* If no pbuf available, just drain the RX fifo. */
  else {
    for(i = 4; i < len; i+=4) {
      temp = HWREG(ETH_BASE + MAC_O_DATA);
    }

    /* Adjust the link statistics */
    LINK_STATS_INC(link.memerr);
    LINK_STATS_INC(link.drop);
  }

  return(p);
}

/**
 * This function should be called when a packet is ready to be read
 * from the interface. It uses the function low_level_input() that
 * should handle the actual reception of bytes from the network
 * interface. Then the type of the received packet is determined and
 * the appropriate input function is called.
 *
 * @param netif the lwip network interface structure for this ethernetif
 */
int
stellarisif_input(struct netif *netif)
{
  struct ethernetif *ethernetif;
  struct pbuf *p;
  int count = 0;

  ethernetif = netif->state;

  /* move received packet into a new pbuf */
  while((p = dequeue_packet(&ethernetif->rxq)) != NULL) {
    count++;
    /* process the packet. */
    if (ethernet_input(p, netif)!=ERR_OK) {
      LWIP_DEBUGF(NETIF_DEBUG, ("stellarisif_input: input error\n"));
      pbuf_free(p);
      p = NULL;
    }
  }

  return(count);
}

/**
 * Should be called at the beginning of the program to set up the
 * network interface. It calls the function low_level_init() to do the
 * actual setup of the hardware.
 *
 * This function should be passed as a parameter to netif_add().
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return ERR_OK if the loopif is initialized
 *         ERR_MEM if private data couldn't be allocated
 *         any other err_t on error
 */
err_t
stellarisif_init(struct netif *netif)
{
  LWIP_ASSERT("netif != NULL", (netif != NULL));

#if LWIP_NETIF_HOSTNAME
  /* Initialize interface hostname */
  netif->hostname = "lwip";
#endif /* LWIP_NETIF_HOSTNAME */

  /*
   * Initialize the snmp variables and counters inside the struct netif.
   * The last argument should be replaced with your link speed, in units
   * of bits per second.
   */
  NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, 1000000);

  netif->state = &ethernetif_data;
  netif->name[0] = IFNAME0;
  netif->name[1] = IFNAME1;
  /* We directly use etharp_output() here to save a function call.
   * You can instead declare your own function an call etharp_output()
   * from it if you have to do some checks before sending (e.g. if link
   * is available...) */
  netif->output = etharp_output;
  netif->linkoutput = low_level_output;

  ethernetif_data.ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
  ethernetif_data.txq.qread = ethernetif_data.txq.qwrite = 0;
  ethernetif_data.txq.overflow = 0;
  ethernetif_data.rxq.qread = ethernetif_data.rxq.qwrite = 0;
  ethernetif_data.rxq.overflow = 0;

  /* initialize the hardware */
  low_level_init(netif);

  return ERR_OK;
}

/**
 * Process tx and rx packets at the low-level interrupt.
 *
 * Should be called from the Stellaris Ethernet Interrupt Handler.  This
 * function will read packets from the Stellaris Ethernet fifo and place them
 * into a pbuf queue.  If the transmitter is idle and there is at least one packet
 * on the transmit queue, it will place it in the transmit fifo and start the
 * transmitter.
 *
 */
void
stellarisif_interrupt(struct netif *netif)
{
  struct ethernetif *ethernetif;
  struct pbuf *p;

  /* setup pointer to the if state data */
  ethernetif = netif->state;

  /**
   * Process the transmit and receive queues as long as there is receive
   * data available
   *
   */
  p = low_level_receive(netif);
  while(p != NULL) {
    /* Add the rx packet to the rx queue */
    if(!enqueue_packet(p, &ethernetif->rxq)) {
      /* Could not place the packet on the queue, bail out. */
      pbuf_free(p);
      break;
    }

    /* Check if TX fifo is empty and packet available */
    if((HWREG(ETH_BASE + MAC_O_TR) & MAC_TR_NEWTX) == 0) {
      p = dequeue_packet(&ethernetif->txq);
      if(p != NULL) {
        low_level_transmit(netif, p);
      }
    }

    /* Read another packet from the RX fifo */
    p = low_level_receive(netif);
  }

  /* One more check of the transmit queue/fifo */
  if((HWREG(ETH_BASE + MAC_O_TR) & MAC_TR_NEWTX) == 0) {
    p = dequeue_packet(&ethernetif->txq);
    if(p != NULL) {
      low_level_transmit(netif, p);
    }
  }
}

#if NETIF_DEBUG
/* Print an IP header by using LWIP_DEBUGF
 * @param p an IP packet, p->payload pointing to the IP header
 */
void
stellarisif_debug_print(struct pbuf *p)
{
  struct eth_hdr *ethhdr = (struct eth_hdr *)p->payload;
  u16_t *plen = (u16_t *)p->payload;

  LWIP_DEBUGF(NETIF_DEBUG, ("ETH header:\n"));
  LWIP_DEBUGF(NETIF_DEBUG, ("Packet Length:%5"U16_F" \n",*plen));
  LWIP_DEBUGF(NETIF_DEBUG, ("Destination: %02"X8_F"-%02"X8_F"-%02"X8_F"-%02"X8_F"-%02"X8_F"-%02"X8_F"\n",
    ethhdr->dest.addr[0],
    ethhdr->dest.addr[1],
    ethhdr->dest.addr[2],
    ethhdr->dest.addr[3],
    ethhdr->dest.addr[4],
    ethhdr->dest.addr[5]));
  LWIP_DEBUGF(NETIF_DEBUG, ("Source: %02"X8_F"-%02"X8_F"-%02"X8_F"-%02"X8_F"-%02"X8_F"-%02"X8_F"\n",
    ethhdr->src.addr[0],
    ethhdr->src.addr[1],
    ethhdr->src.addr[2],
    ethhdr->src.addr[3],
    ethhdr->src.addr[4],
    ethhdr->src.addr[5]));
  LWIP_DEBUGF(NETIF_DEBUG, ("Packet Type:0x%04"U16_F" \n", ethhdr->type));
}
#endif /* NETIF_DEBUG */