TX_REG_DESC_SIZE
desc = priv->tx_desc_base + i * TX_REG_DESC_SIZE;
memset(desc, 0, TX_REG_DESC_SIZE);
desc = priv->tx_desc_base + (TX_REG_DESC_SIZE * tx_head);
priv->tx_desc_base = dma_alloc_coherent(p_dev, TX_REG_DESC_SIZE *
TX_REG_DESC_SIZE * TX_DESC_NUM,