1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/net/spider_net.c b/drivers/net/spider_net.c
index d779a0b9d456..96b5d00c21da 100644
--- a/drivers/net/spider_net.c
+++ b/drivers/net/spider_net.c
@@ -684,6 +684,7 @@ spider_net_prepare_tx_descr(struct spider_net_card *card,
                         break;
                 }
 
+        /* Chain the bus address, so that the DMA engine finds this descr. */
         descr->prev->next_descr_addr = descr->bus_addr;
 
         card->netdev->trans_start = jiffies; /* set netdev watchdog timer */
@@ -717,6 +718,41 @@ spider_net_release_tx_descr(struct spider_net_card *card)
         dev_kfree_skb_any(skb);
 }
 
+static void
+spider_net_set_low_watermark(struct spider_net_card *card)
+{
+        int status;
+        int cnt=0;
+        int i;
+        struct spider_net_descr *descr = card->tx_chain.tail;
+
+        /* Measure the length of the queue. */
+        while (descr != card->tx_chain.head) {
+                status = descr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
+                if (status == SPIDER_NET_DESCR_NOT_IN_USE)
+                        break;
+                descr = descr->next;
+                cnt++;
+        }
+
+        /* If TX queue is short, don't even bother with interrupts */
+        if (cnt < card->tx_desc/4)
+                return;
+
+        /* Set low-watermark 3/4th's of the way into the queue. */
+        descr = card->tx_chain.tail;
+        cnt = (cnt*3)/4;
+        for (i=0;i<cnt; i++)
+                descr = descr->next;
+
+        /* Set the new watermark, clear the old watermark */
+        descr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
+        if (card->low_watermark && card->low_watermark != descr)
+                card->low_watermark->dmac_cmd_status =
+                     card->low_watermark->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
+        card->low_watermark = descr;
+}
+
 /**
  * spider_net_release_tx_chain - processes sent tx descriptors
  * @card: adapter structure
@@ -838,6 +874,7 @@ spider_net_xmit(struct sk_buff *skb, struct net_device *netdev)
                 return NETDEV_TX_BUSY;
         }
 
+        spider_net_set_low_watermark(card);
         spider_net_kick_tx_dma(card);
         card->tx_chain.head = card->tx_chain.head->next;
         spin_unlock_irqrestore(&chain->lock, flags);
@@ -1467,6 +1504,10 @@ spider_net_interrupt(int irq, void *ptr)
                 spider_net_rx_irq_off(card);
                 netif_rx_schedule(netdev);
         }
+        if (status_reg & SPIDER_NET_TXINT ) {
+                spider_net_cleanup_tx_ring(card);
+                netif_wake_queue(netdev);
+        }
 
         if (status_reg & SPIDER_NET_ERRINT )
                 spider_net_handle_error_irq(card, status_reg);
@@ -1629,6 +1670,8 @@ spider_net_open(struct net_device *netdev)
                         PCI_DMA_TODEVICE, card->tx_desc))
                 goto alloc_tx_failed;
 
+        card->low_watermark = NULL;
+
         /* rx_chain is after tx_chain, so offset is descr + tx_count */
         if (spider_net_init_chain(card, &card->rx_chain,
                         card->descr + card->tx_desc,