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 |