ethernetif.c

LWIP在STM32裸机上的移植

  len = frame.length;
  
  buffer = (u8 *)frame.buffer;

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

  if (p != NULL)
  {
    /* We iterate over the pbuf chain until we have read the entire
     * packet into the pbuf. */
    for (q = p; q != NULL; q = q->next)
    {
	  /* Read enough bytes to fill this pbuf in the chain. 
       * The available data in the pbuf is given by the q->len variable.
       */  
	  memcpy((u8_t*)q->payload, (u8_t*)&buffer[l], q->len);
      l = l + q->len;
    }    
  }

  /* Set Own bit of the Rx descriptor Status: gives the buffer back to ETHERNET DMA */
  frame.descriptor->Status = ETH_DMARxDesc_OWN; 
 
  /* When Rx Buffer unavailable flag is set: clear it and resume reception */
  if ((ETH->DMASR & ETH_DMASR_RBUS) != (u32)RESET)  
  {
    /* Clear RBUS ETHERNET DMA flag */
    ETH->DMASR = ETH_DMASR_RBUS;
    
	/* Resume DMA reception */
    ETH->DMARPDR = 0;
  }

  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
 */
err_t
ethernetif_input(struct netif *netif)
{
  err_t err;
  struct pbuf *p;

  /* move received packet into a new pbuf */
  p = low_level_input(netif);

  /* no packet could be read, silently ignore this */
  if (p == NULL) return ERR_MEM;

  err = netif->input(p, netif);
  if (err != ERR_OK)
  {
    LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
    pbuf_free(p);
    p = NULL;
  }

  return err;
}

/**
 * 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
ethernetif_init(struct netif *netif)
{
  struct ethernetif *ethernetif;

  LWIP_ASSERT("netif != NULL", (netif != NULL));

  ethernetif = mem_malloc(sizeof(struct ethernetif));
  if (ethernetif == NULL)
  {
    LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
    return ERR_MEM;
  }

#if LWIP_NETIF_HOSTNAME
  /* Initialize interface hostname */
  netif->hostname = "CSU_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, 100000000);

  netif->state = ethernetif;
  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->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);

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

  return ERR_OK;
}

/*******************************************************************************
* Function Name  : ETH_RxPkt_ChainMode
* Description    : Receives a packet.
* Input          : None
* Output         : None
* Return         : frame: farme size and location
*******************************************************************************/
FrameTypeDef ETH_RxPkt_ChainMode(void)
{ 
  u32 framelength = 0;
  FrameTypeDef frame = {0,0}; 

  /* Check if the descriptor is owned by the ETHERNET DMA (when set) or CPU (when reset) */
  if((DMARxDescToGet->Status & ETH_DMARxDesc_OWN) != (u32)RESET)
  {	
	frame.length = ETH_ERROR;

    if ((ETH->DMASR & ETH_DMASR_RBUS) != (u32)RESET)  
    {
      /* Clear RBUS ETHERNET DMA flag */
      ETH->DMASR = ETH_DMASR_RBUS;
      /* Resume DMA reception */
      ETH->DMARPDR = 0;
    }

	/* Return error: OWN bit set */
    return frame; 
  }
  
  if(((DMARxDescToGet->Status & ETH_DMARxDesc_ES) == (u32)RESET) && 
     ((DMARxDescToGet->Status & ETH_DMARxDesc_LS) != (u32)RESET) &&  
     ((DMARxDescToGet->Status & ETH_DMARxDesc_FS) != (u32)RESET))  
  {      
    /* Get the Frame Length of the received packet: substruct 4 bytes of the CRC */
    framelength = ((DMARxDescToGet->Status & ETH_DMARxDesc_FL) >> ETH_DMARxDesc_FrameLengthShift) - 4;
	
	/* Get the addrees of the actual buffer */
	frame.buffer = DMARxDescToGet->Buffer1Addr;	
  }
  else
  {
    /* Return ERROR */
    framelength = ETH_ERROR;
  }

  frame.length = framelength;


  frame.descriptor = DMARxDescToGet;
  
  /* Update the ETHERNET DMA global Rx descriptor with next Rx decriptor */      
  /* Chained Mode */    
  /* Selects the next DMA Rx descriptor list for next buffer to read */ 
  DMARxDescToGet = (ETH_DMADESCTypeDef*) (DMARxDescToGet->Buffer2NextDescAddr);    
  
  /* Return Frame */
  return (frame);  
}

/*******************************************************************************
* Function Name  : ETH_TxPkt_ChainMode
* Description    : Transmits a packet, from application buffer, pointed by ppkt.
* Input          : - FrameLength: Tx Packet size.
* Output         : None
* Return         : ETH_ERROR: in case of Tx desc owned by DMA
*                  ETH_SUCCESS: for correct transmission
*******************************************************************************/
u32 ETH_TxPkt_ChainMode(u16 FrameLength)
{   
  /* Check if the descriptor is owned by the ETHERNET DMA (when set) or CPU (when reset) */
  if((DMATxDescToSet->Status & ETH_DMATxDesc_OWN) != (u32)RESET)
  {  
	/* Return ERROR: OWN bit set */
    return ETH_ERROR;
  }
        
  /* Setting the Frame Length: bits[12:0] */
  DMATxDescToSet->ControlBufferSize = (FrameLength & ETH_DMATxDesc_TBS1);

  /* Setting the last segment and first segment bits (in this case a frame is transmitted in one descriptor) */    
  DMATxDescToSet->Status |= ETH_DMATxDesc_LS | ETH_DMATxDesc_FS;

  /* Set Own bit of the Tx descriptor Status: gives the buffer back to ETHERNET DMA */
  DMATxDescToSet->Status |= ETH_DMATxDesc_OWN;

  /* When Tx Buffer unavailable flag is set: clear it and resume transmission */
  if ((ETH->DMASR & ETH_DMASR_TBUS) != (u32)RESET)
  {
    /* Clear TBUS ETHERNET DMA flag */
    ETH->DMASR = ETH_DMASR_TBUS;
    /* Resume DMA transmission*/
    ETH->DMATPDR = 0;
  }
  
  /* Update the ETHERNET DMA global Tx descriptor with next Tx decriptor */  
  /* Chained Mode */
  /* Selects the next DMA Tx descriptor list for next buffer to send */ 
  DMATxDescToSet = (ETH_DMADESCTypeDef*) (DMATxDescToSet->Buffer2NextDescAddr);    


  /* Return SUCCESS */
  return ETH_SUCCESS;   
}


/*******************************************************************************
* Function Name  : ETH_GetCurrentTxBuffer
* Description    : Return the address of the buffer pointed by the current descritor.
* Input          : None
* Output         : None
* Return         : Buffer address
*******************************************************************************/
u32 ETH_GetCurrentTxBuffer(void)
{ 
  /* Return Buffer address */
  return (DMATxDescToSet->Buffer1Addr);   
}