+ if (adapter->hw.mac_type == e1000_82547) {
+ adapter->tx_fifo_head = 0;
+ adapter->tx_head_addr = pba << E1000_TX_HEAD_ADDR_SHIFT;
+ adapter->tx_fifo_size =
+ (E1000_PBA_40K - pba) << E1000_PBA_BYTES_SHIFT;
+ atomic_set(&adapter->tx_fifo_stall, 0);
+ }
+ } else if (adapter->hw.max_frame_size > MAXIMUM_ETHERNET_FRAME_SIZE) {
+ /* adjust PBA for jumbo frames */
+ E1000_WRITE_REG(&adapter->hw, PBA, pba);
+
+ /* To maintain wire speed transmits, the Tx FIFO should be
+ * large enough to accomodate two full transmit packets,
+ * rounded up to the next 1KB and expressed in KB. Likewise,
+ * the Rx FIFO should be large enough to accomodate at least
+ * one full receive packet and is similarly rounded up and
+ * expressed in KB. */
+ pba = E1000_READ_REG(&adapter->hw, PBA);
+ /* upper 16 bits has Tx packet buffer allocation size in KB */
+ tx_space = pba >> 16;
+ /* lower 16 bits has Rx packet buffer allocation size in KB */
+ pba &= 0xffff;
+ /* don't include ethernet FCS because hardware appends/strips */
+ min_rx_space = adapter->netdev->mtu + ENET_HEADER_SIZE +
+ VLAN_TAG_SIZE;
+ min_tx_space = min_rx_space;
+ min_tx_space *= 2;
+ E1000_ROUNDUP(min_tx_space, 1024);
+ min_tx_space >>= 10;
+ E1000_ROUNDUP(min_rx_space, 1024);
+ min_rx_space >>= 10;
+
+ /* If current Tx allocation is less than the min Tx FIFO size,
+ * and the min Tx FIFO size is less than the current Rx FIFO
+ * allocation, take space away from current Rx allocation */
+ if (tx_space < min_tx_space &&
+ ((min_tx_space - tx_space) < pba)) {
+ pba = pba - (min_tx_space - tx_space);
+
+ /* PCI/PCIx hardware has PBA alignment constraints */
+ switch (adapter->hw.mac_type) {
+ case e1000_82545 ... e1000_82546_rev_3:
+ pba &= ~(E1000_PBA_8K - 1);
+ break;
+ default:
+ break;
+ }