STM32F407+FreeRTOS+Ethernet(DP83848)+Lwip实现socket通信

HR91105A是这个

CubeMx GPIO配置如下（通过原理图可以看到是RMII接口）：

low_level_output是 lwip 往网卡驱动发送函数，代码如下：

此函数就是把lwip的pbuf数据copy到eth的tx dma中，然后发送

static err_t low_level_output(struct netif *netif, struct pbuf *p)

{

  err_t errval;

  struct pbuf *q;

  uint8_t *buffer = (uint8_t *)(heth.TxDesc->Buffer1Addr);

  __IO ETH_DMADescTypeDef *DmaTxDesc;

  uint32_t framelength = 0;

  uint32_t bufferoffset = 0;

  uint32_t byteslefttocopy = 0;

  uint32_t payloadoffset = 0;

  DmaTxDesc = heth.TxDesc;

  bufferoffset = 0;

  /* copy frame from pbufs to driver buffers */

  for(q = p; q != NULL; q = q->next)

    {

      /* Is this buffer available? If not, goto error */

      if((DmaTxDesc->Status & ETH_DMATXDESC_OWN) != (uint32_t)RESET)

      {

        errval = ERR_USE;

        goto error;

      }

      /* Get bytes in current lwIP buffer */

      byteslefttocopy = q->len;

      payloadoffset = 0;

      /* Check if the length of data to copy is bigger than Tx buffer size*/

      while( (byteslefttocopy + bufferoffset) > ETH_TX_BUF_SIZE )

      {

        /* Copy data to Tx buffer*/

        memcpy( (uint8_t*)((uint8_t*)buffer + bufferoffset), (uint8_t*)((uint8_t*)q->payload + payloadoffset), (ETH_TX_BUF_SIZE - bufferoffset) );

        /* Point to next descriptor */

        DmaTxDesc = (ETH_DMADescTypeDef *)(DmaTxDesc->Buffer2NextDescAddr);

        /* Check if the buffer is available */

        if((DmaTxDesc->Status & ETH_DMATXDESC_OWN) != (uint32_t)RESET)

        {

          errval = ERR_USE;

          goto error;

        }

        buffer = (uint8_t *)(DmaTxDesc->Buffer1Addr);

        byteslefttocopy = byteslefttocopy - (ETH_TX_BUF_SIZE - bufferoffset);

        payloadoffset = payloadoffset + (ETH_TX_BUF_SIZE - bufferoffset);

        framelength = framelength + (ETH_TX_BUF_SIZE - bufferoffset);

        bufferoffset = 0;

      }

      /* Copy the remaining bytes */

      memcpy( (uint8_t*)((uint8_t*)buffer + bufferoffset), (uint8_t*)((uint8_t*)q->payload + payloadoffset), byteslefttocopy );

      bufferoffset = bufferoffset + byteslefttocopy;

      framelength = framelength + byteslefttocopy;

    }

  /* Prepare transmit descriptors to give to DMA */

  HAL_ETH_TransmitFrame(&heth, framelength);

  errval = ERR_OK;

error:

  /* When Transmit Underflow flag is set, clear it and issue a Transmit Poll Demand to resume transmission */

  if ((heth.Instance->DMASR & ETH_DMASR_TUS) != (uint32_t)RESET)

  {

    /* Clear TUS ETHERNET DMA flag */

    heth.Instance->DMASR = ETH_DMASR_TUS;

    /* Resume DMA transmission*/

    heth.Instance->DMATPDR = 0;

  }

  return errval;

}

low_level_input是lwip接受input数据，代码如下：

此函数就是把eth的rx dma中数据copy到pbuf中，然后交给lwip处理

static struct pbuf * low_level_input(struct netif *netif)

{

  struct pbuf *p = NULL;

  struct pbuf *q = NULL;

  uint16_t len = 0;

  uint8_t *buffer;

  __IO ETH_DMADescTypeDef *dmarxdesc;

  uint32_t bufferoffset = 0;

  uint32_t payloadoffset = 0;

  uint32_t byteslefttocopy = 0;

  uint32_t i=0;

  /* get received frame */

  if (HAL_ETH_GetReceivedFrame(&heth) != HAL_OK)

    return NULL;

  /* Obtain the size of the packet and put it into the "len" variable. */

  len = heth.RxFrameInfos.length;

  buffer = (uint8_t *)heth.RxFrameInfos.buffer;

  if (len > 0)

  {

    /* We allocate a pbuf chain of pbufs from the Lwip buffer pool */

    p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);

  }

  if (p != NULL)

  {

    dmarxdesc = heth.RxFrameInfos.FSRxDesc;

    bufferoffset = 0;

    for(q = p; q != NULL; q = q->next)

    {

      byteslefttocopy = q->len;

      payloadoffset = 0;

      /* Check if the length of bytes to copy in current pbuf is bigger than Rx buffer size*/

      while( (byteslefttocopy + bufferoffset) > ETH_RX_BUF_SIZE )

      {

        /* Copy data to pbuf */

        memcpy( (uint8_t*)((uint8_t*)q->payload + payloadoffset), (uint8_t*)((uint8_t*)buffer + bufferoffset), (ETH_RX_BUF_SIZE - bufferoffset));

        /* Point to next descriptor */

        dmarxdesc = (ETH_DMADescTypeDef *)(dmarxdesc->Buffer2NextDescAddr);

        buffer = (uint8_t *)(dmarxdesc->Buffer1Addr);

        byteslefttocopy = byteslefttocopy - (ETH_RX_BUF_SIZE - bufferoffset);

        payloadoffset = payloadoffset + (ETH_RX_BUF_SIZE - bufferoffset);

        bufferoffset = 0;

      }

      /* Copy remaining data in pbuf */

      memcpy( (uint8_t*)((uint8_t*)q->payload + payloadoffset), (uint8_t*)((uint8_t*)buffer + bufferoffset), byteslefttocopy);

      bufferoffset = bufferoffset + byteslefttocopy;

    }

  }

    /* Release descriptors to DMA */

    /* Point to first descriptor */

    dmarxdesc = heth.RxFrameInfos.FSRxDesc;

    /* Set Own bit in Rx descriptors: gives the buffers back to DMA */

    for (i=0; i< heth.RxFrameInfos.SegCount; i++)

    {

      dmarxdesc->Status |= ETH_DMARXDESC_OWN;

      dmarxdesc = (ETH_DMADescTypeDef *)(dmarxdesc->Buffer2NextDescAddr);

    }

    /* Clear Segment_Count */

    heth.RxFrameInfos.SegCount =0;

  /* When Rx Buffer unavailable flag is set: clear it and resume reception */

  if ((heth.Instance->DMASR & ETH_DMASR_RBUS) != (uint32_t)RESET)

  {

    /* Clear RBUS ETHERNET DMA flag */

    heth.Instance->DMASR = ETH_DMASR_RBUS;

    /* Resume DMA reception */

    heth.Instance->DMARPDR = 0;

  }

  return p;

}