b44: Fix frequent link changes

This fixes the issue of frequent link changes under heavy traffic reported
below:

http://bugzilla.kernel.org/show_bug.cgi?id=7696
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216338

The b44 chip occasionally needs to be reset when ISTAT_ERRORS are
encountered.  The reset sequence includes a PHY reset that will take many
seconds to complete and cause the link to go down and up.  By skipping the
PHY reset, it will greatly reduce the interruption when ISTAT_ERRORS are
encountered.

Change the full_reset parameter to reset_kind parameter in b44_init_hw().
This will allow PHY reset to be skipped when ISTAT_ERRORS are encountered.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/b44.c

@@ -110,6 +110,11 @@ MODULE_DEVICE_TABLE(pci, b44_pci_tbl);
 
 static void b44_halt(struct b44 *);
 static void b44_init_rings(struct b44 *);
+
+#define B44_FULL_RESET		1
+#define B44_FULL_RESET_SKIP_PHY	2
+#define B44_PARTIAL_RESET	3
+
 static void b44_init_hw(struct b44 *, int);
 
 static int dma_desc_align_mask;
@@ -884,7 +889,7 @@ static int b44_poll(struct net_device *netdev, int *budget)
 		spin_lock_irqsave(&bp->lock, flags);
 		b44_halt(bp);
 		b44_init_rings(bp);
-		b44_init_hw(bp, 1);
+		b44_init_hw(bp, B44_FULL_RESET_SKIP_PHY);
 		netif_wake_queue(bp->dev);
 		spin_unlock_irqrestore(&bp->lock, flags);
 		done = 1;
@@ -954,7 +959,7 @@ static void b44_tx_timeout(struct net_device *dev)
 
 	b44_halt(bp);
 	b44_init_rings(bp);
-	b44_init_hw(bp, 1);
+	b44_init_hw(bp, B44_FULL_RESET);
 
 	spin_unlock_irq(&bp->lock);
 
@@ -1071,7 +1076,7 @@ static int b44_change_mtu(struct net_device *dev, int new_mtu)
 	b44_halt(bp);
 	dev->mtu = new_mtu;
 	b44_init_rings(bp);
-	b44_init_hw(bp, 1);
+	b44_init_hw(bp, B44_FULL_RESET);
 	spin_unlock_irq(&bp->lock);
 
 	b44_enable_ints(bp);
@@ -1368,12 +1373,12 @@ static int b44_set_mac_addr(struct net_device *dev, void *p)
  * packet processing.  Invoked with bp->lock held.
  */
 static void __b44_set_rx_mode(struct net_device *);
-static void b44_init_hw(struct b44 *bp, int full_reset)
+static void b44_init_hw(struct b44 *bp, int reset_kind)
 {
 	u32 val;
 
 	b44_chip_reset(bp);
-	if (full_reset) {
+	if (reset_kind == B44_FULL_RESET) {
 		b44_phy_reset(bp);
 		b44_setup_phy(bp);
 	}
@@ -1390,7 +1395,10 @@ static void b44_init_hw(struct b44 *bp, int full_reset)
 	bw32(bp, B44_TXMAXLEN, bp->dev->mtu + ETH_HLEN + 8 + RX_HEADER_LEN);
 
 	bw32(bp, B44_TX_WMARK, 56); /* XXX magic */
-	if (full_reset) {
+	if (reset_kind == B44_PARTIAL_RESET) {
+		bw32(bp, B44_DMARX_CTRL, (DMARX_CTRL_ENABLE |
+				      (bp->rx_offset << DMARX_CTRL_ROSHIFT)));
+	} else {
 		bw32(bp, B44_DMATX_CTRL, DMATX_CTRL_ENABLE);
 		bw32(bp, B44_DMATX_ADDR, bp->tx_ring_dma + bp->dma_offset);
 		bw32(bp, B44_DMARX_CTRL, (DMARX_CTRL_ENABLE |
@@ -1401,9 +1409,6 @@ static void b44_init_hw(struct b44 *bp, int full_reset)
 		bp->rx_prod = bp->rx_pending;
 
 		bw32(bp, B44_MIB_CTRL, MIB_CTRL_CLR_ON_READ);
-	} else {
-		bw32(bp, B44_DMARX_CTRL, (DMARX_CTRL_ENABLE |
-				      (bp->rx_offset << DMARX_CTRL_ROSHIFT)));
 	}
 
 	val = br32(bp, B44_ENET_CTRL);
@@ -1420,7 +1425,7 @@ static int b44_open(struct net_device *dev)
 		goto out;
 
 	b44_init_rings(bp);
-	b44_init_hw(bp, 1);
+	b44_init_hw(bp, B44_FULL_RESET);
 
 	b44_check_phy(bp);
 
@@ -1629,7 +1634,7 @@ static int b44_close(struct net_device *dev)
 	netif_poll_enable(dev);
 
 	if (bp->flags & B44_FLAG_WOL_ENABLE) {
-		b44_init_hw(bp, 0);
+		b44_init_hw(bp, B44_PARTIAL_RESET);
 		b44_setup_wol(bp);
 	}
 
@@ -1905,7 +1910,7 @@ static int b44_set_ringparam(struct net_device *dev,
 
 	b44_halt(bp);
 	b44_init_rings(bp);
-	b44_init_hw(bp, 1);
+	b44_init_hw(bp, B44_FULL_RESET);
 	netif_wake_queue(bp->dev);
 	spin_unlock_irq(&bp->lock);
 
@@ -1948,7 +1953,7 @@ static int b44_set_pauseparam(struct net_device *dev,
 	if (bp->flags & B44_FLAG_PAUSE_AUTO) {
 		b44_halt(bp);
 		b44_init_rings(bp);
-		b44_init_hw(bp, 1);
+		b44_init_hw(bp, B44_FULL_RESET);
 	} else {
 		__b44_set_flow_ctrl(bp, bp->flags);
 	}
@@ -2304,7 +2309,7 @@ static int b44_suspend(struct pci_dev *pdev, pm_message_t state)
 
 	free_irq(dev->irq, dev);
 	if (bp->flags & B44_FLAG_WOL_ENABLE) {
-		b44_init_hw(bp, 0);
+		b44_init_hw(bp, B44_PARTIAL_RESET);
 		b44_setup_wol(bp);
 	}
 	pci_disable_device(pdev);
@@ -2329,7 +2334,7 @@ static int b44_resume(struct pci_dev *pdev)
 	spin_lock_irq(&bp->lock);
 
 	b44_init_rings(bp);
-	b44_init_hw(bp, 1);
+	b44_init_hw(bp, B44_FULL_RESET);
 	netif_device_attach(bp->dev);
 	spin_unlock_irq(&bp->lock);