1 files changed, 48 insertions, 38 deletions

diff --git a/drivers/net/ethernet/aeroflex/greth.c b/drivers/net/ethernet/aeroflex/greth.c
index 23578dfee249..3005155e412b 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/drivers/net/ethernet/aeroflex/greth.c
@@ -123,6 +123,12 @@ static inline void greth_enable_tx(struct greth_private *greth)
         GRETH_REGORIN(greth->regs->control, GRETH_TXEN);
 }
 
+static inline void greth_enable_tx_and_irq(struct greth_private *greth)
+{
+        wmb(); /* BDs must been written to memory before enabling TX */
+        GRETH_REGORIN(greth->regs->control, GRETH_TXEN | GRETH_TXI);
+}
+
 static inline void greth_disable_tx(struct greth_private *greth)
 {
         GRETH_REGANDIN(greth->regs->control, ~GRETH_TXEN);
@@ -447,29 +453,30 @@ out:
         return err;
 }
 
+static inline u16 greth_num_free_bds(u16 tx_last, u16 tx_next)
+{
+        if (tx_next < tx_last)
+                return (tx_last - tx_next) - 1;
+        else
+                return GRETH_TXBD_NUM - (tx_next - tx_last) - 1;
+}
 
 static netdev_tx_t
 greth_start_xmit_gbit(struct sk_buff *skb, struct net_device *dev)
 {
         struct greth_private *greth = netdev_priv(dev);
         struct greth_bd *bdp;
-        u32 status = 0, dma_addr, ctrl;
+        u32 status, dma_addr;
         int curr_tx, nr_frags, i, err = NETDEV_TX_OK;
         unsigned long flags;
+        u16 tx_last;
 
         nr_frags = skb_shinfo(skb)->nr_frags;
+        tx_last = greth->tx_last;
+        rmb(); /* tx_last is updated by the poll task */
 
-        /* Clean TX Ring */
-        greth_clean_tx_gbit(dev);
-
-        if (greth->tx_free < nr_frags + 1) {
-                spin_lock_irqsave(&greth->devlock, flags);/*save from poll/irq*/
-                ctrl = GRETH_REGLOAD(greth->regs->control);
-                /* Enable TX IRQ only if not already in poll() routine */
-                if (ctrl & GRETH_RXI)
-                        GRETH_REGSAVE(greth->regs->control, ctrl | GRETH_TXI);
+        if (greth_num_free_bds(tx_last, greth->tx_next) < nr_frags + 1) {
                 netif_stop_queue(dev);
-                spin_unlock_irqrestore(&greth->devlock, flags);
                 err = NETDEV_TX_BUSY;
                 goto out;
         }
@@ -488,6 +495,8 @@ greth_start_xmit_gbit(struct sk_buff *skb, struct net_device *dev)
         /* Linear buf */
         if (nr_frags != 0)
                 status = GRETH_TXBD_MORE;
+        else
+                status = GRETH_BD_IE;
 
         if (skb->ip_summed == CHECKSUM_PARTIAL)
                 status |= GRETH_TXBD_CSALL;
@@ -545,14 +554,12 @@ greth_start_xmit_gbit(struct sk_buff *skb, struct net_device *dev)
 
         /* Enable the descriptor chain by enabling the first descriptor */
         bdp = greth->tx_bd_base + greth->tx_next;
-        greth_write_bd(&bdp->stat, greth_read_bd(&bdp->stat) | GRETH_BD_EN);
-        greth->tx_next = curr_tx;
-        greth->tx_free -= nr_frags + 1;
-
-        wmb();
+        greth_write_bd(&bdp->stat,
+                       greth_read_bd(&bdp->stat) | GRETH_BD_EN);
 
         spin_lock_irqsave(&greth->devlock, flags); /*save from poll/irq*/
-        greth_enable_tx(greth);
+        greth->tx_next = curr_tx;
+        greth_enable_tx_and_irq(greth);
         spin_unlock_irqrestore(&greth->devlock, flags);
 
         return NETDEV_TX_OK;
@@ -648,7 +655,6 @@ static void greth_clean_tx(struct net_device *dev)
         if (greth->tx_free > 0) {
                 netif_wake_queue(dev);
         }
-
 }
 
 static inline void greth_update_tx_stats(struct net_device *dev, u32 stat)
@@ -670,20 +676,22 @@ static void greth_clean_tx_gbit(struct net_device *dev)
 {
         struct greth_private *greth;
         struct greth_bd *bdp, *bdp_last_frag;
-        struct sk_buff *skb;
+        struct sk_buff *skb = NULL;
         u32 stat;
         int nr_frags, i;
+        u16 tx_last;
 
         greth = netdev_priv(dev);
+        tx_last = greth->tx_last;
 
-        while (greth->tx_free < GRETH_TXBD_NUM) {
+        while (tx_last != greth->tx_next) {
 
-                skb = greth->tx_skbuff[greth->tx_last];
+                skb = greth->tx_skbuff[tx_last];
 
                 nr_frags = skb_shinfo(skb)->nr_frags;
 
                 /* We only clean fully completed SKBs */
-                bdp_last_frag = greth->tx_bd_base + SKIP_TX(greth->tx_last, nr_frags);
+                bdp_last_frag = greth->tx_bd_base + SKIP_TX(tx_last, nr_frags);
 
                 GRETH_REGSAVE(greth->regs->status, GRETH_INT_TE | GRETH_INT_TX);
                 mb();
@@ -692,14 +700,14 @@ static void greth_clean_tx_gbit(struct net_device *dev)
                 if (stat & GRETH_BD_EN)
                         break;
 
-                greth->tx_skbuff[greth->tx_last] = NULL;
+                greth->tx_skbuff[tx_last] = NULL;
 
                 greth_update_tx_stats(dev, stat);
                 dev->stats.tx_bytes += skb->len;
 
-                bdp = greth->tx_bd_base + greth->tx_last;
+                bdp = greth->tx_bd_base + tx_last;
 
-                greth->tx_last = NEXT_TX(greth->tx_last);
+                tx_last = NEXT_TX(tx_last);
 
                 dma_unmap_single(greth->dev,
                                  greth_read_bd(&bdp->addr),
@@ -708,21 +716,26 @@ static void greth_clean_tx_gbit(struct net_device *dev)
 
                 for (i = 0; i < nr_frags; i++) {
                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-                        bdp = greth->tx_bd_base + greth->tx_last;
+                        bdp = greth->tx_bd_base + tx_last;
 
                         dma_unmap_page(greth->dev,
                                        greth_read_bd(&bdp->addr),
                                        skb_frag_size(frag),
                                        DMA_TO_DEVICE);
 
-                        greth->tx_last = NEXT_TX(greth->tx_last);
+                        tx_last = NEXT_TX(tx_last);
                 }
-                greth->tx_free += nr_frags+1;
                 dev_kfree_skb(skb);
         }
+        if (skb) { /* skb is set only if the above while loop was entered */
+                wmb();
+                greth->tx_last = tx_last;
 
-        if (netif_queue_stopped(dev) && (greth->tx_free > (MAX_SKB_FRAGS+1)))
-                netif_wake_queue(dev);
+                if (netif_queue_stopped(dev) &&
+                    (greth_num_free_bds(tx_last, greth->tx_next) >
+                    (MAX_SKB_FRAGS+1)))
+                        netif_wake_queue(dev);
+        }
 }
 
 static int greth_rx(struct net_device *dev, int limit)
@@ -965,16 +978,12 @@ static int greth_poll(struct napi_struct *napi, int budget)
         greth = container_of(napi, struct greth_private, napi);
 
 restart_txrx_poll:
-        if (netif_queue_stopped(greth->netdev)) {
-                if (greth->gbit_mac)
-                        greth_clean_tx_gbit(greth->netdev);
-                else
-                        greth_clean_tx(greth->netdev);
-        }
-
         if (greth->gbit_mac) {
+                greth_clean_tx_gbit(greth->netdev);
                 work_done += greth_rx_gbit(greth->netdev, budget - work_done);
         } else {
+                if (netif_queue_stopped(greth->netdev))
+                        greth_clean_tx(greth->netdev);
                 work_done += greth_rx(greth->netdev, budget - work_done);
         }
 
@@ -983,7 +992,8 @@ restart_txrx_poll:
                 spin_lock_irqsave(&greth->devlock, flags);
 
                 ctrl = GRETH_REGLOAD(greth->regs->control);
-                if (netif_queue_stopped(greth->netdev)) {
+                if ((greth->gbit_mac && (greth->tx_last != greth->tx_next)) ||
+                    (!greth->gbit_mac && netif_queue_stopped(greth->netdev))) {
                         GRETH_REGSAVE(greth->regs->control,
                                         ctrl | GRETH_TXI | GRETH_RXI);
                         mask = GRETH_INT_RX | GRETH_INT_RE |