sky2: Avoid down and up during sky2_reset

Rewrite sky2_reset to work with interrupts disabled and
 avoid freeing and reallocing memory.

The old code used sky2_down and sky2_up to implement sky2_reset,
 which meant interrupts could not be disabled, and the transmit and
 receive ring buffers would be free'd and reallocated.

To avoid the interrupt handler waking the transmit queue while
 we're doing a reset, it's better to have interrupts and NAPI
 polls disabled.

Note: Modified Mike's patch to do IRQ disable in sky2_down before
 calling sky2_hw_down - Stephen

Signed-off-by: Mike McCormack <mikem@ring3k.org>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/sky2.c

@@ -1880,10 +1880,6 @@ static void sky2_tx_complete(struct sky2_port *sky2, u16 done)
 
 	sky2->tx_cons = idx;
 	smp_mb();
-
-	/* Wake unless it's detached, and called e.g. from sky2_down() */
-	if (tx_avail(sky2) > MAX_SKB_TX_LE + 4 && netif_device_present(dev))
-		netif_wake_queue(dev);
 }
 
 static void sky2_tx_reset(struct sky2_hw *hw, unsigned port)
@@ -1912,7 +1908,6 @@ static void sky2_hw_down(struct sky2_port *sky2)
 {
 	struct sky2_hw *hw = sky2->hw;
 	unsigned port = sky2->port;
-	u32 imask;
 	u16 ctrl;
 
 	/* Force flow control off */
@@ -1946,15 +1941,6 @@ static void sky2_hw_down(struct sky2_port *sky2)
 
 	sky2_rx_stop(sky2);
 
-	/* Disable port IRQ */
-	imask = sky2_read32(hw, B0_IMSK);
-	imask &= ~portirq_msk[port];
-	sky2_write32(hw, B0_IMSK, imask);
-	sky2_read32(hw, B0_IMSK);
-
-	synchronize_irq(hw->pdev->irq);
-	napi_synchronize(&hw->napi);
-
 	spin_lock_bh(&sky2->phy_lock);
 	sky2_phy_power_down(hw, port);
 	spin_unlock_bh(&sky2->phy_lock);
@@ -1969,6 +1955,7 @@ static void sky2_hw_down(struct sky2_port *sky2)
 static int sky2_down(struct net_device *dev)
 {
 	struct sky2_port *sky2 = netdev_priv(dev);
+	struct sky2_hw *hw = sky2->hw;
 
 	/* Never really got started! */
 	if (!sky2->tx_le)
@@ -1977,6 +1964,14 @@ static int sky2_down(struct net_device *dev)
 	if (netif_msg_ifdown(sky2))
 		printk(KERN_INFO PFX "%s: disabling interface\n", dev->name);
 
+	/* Disable port IRQ */
+	sky2_write32(hw, B0_IMSK,
+		     sky2_read32(hw, B0_IMSK) & ~portirq_msk[sky2->port]);
+	sky2_read32(hw, B0_IMSK);
+
+	synchronize_irq(hw->pdev->irq);
+	napi_synchronize(&hw->napi);
+
 	sky2_hw_down(sky2);
 
 	sky2_free_buffers(sky2);
@@ -2475,8 +2470,13 @@ static inline void sky2_tx_done(struct net_device *dev, u16 last)
 {
 	struct sky2_port *sky2 = netdev_priv(dev);
 
-	if (netif_running(dev))
+	if (netif_running(dev)) {
 		sky2_tx_complete(sky2, last);
+
+		/* Wake unless it's detached, and called e.g. from sky2_down() */
+		if (tx_avail(sky2) > MAX_SKB_TX_LE + 4)
+			netif_wake_queue(dev);
+	}
 }
 
 static inline void sky2_skb_rx(const struct sky2_port *sky2,
@@ -3277,20 +3277,46 @@ static int sky2_reattach(struct net_device *dev)
 static void sky2_restart(struct work_struct *work)
 {
 	struct sky2_hw *hw = container_of(work, struct sky2_hw, restart_work);
+	u32 imask;
 	int i;
 
 	rtnl_lock();
-	for (i = 0; i < hw->ports; i++)
-		sky2_detach(hw->dev[i]);
 
 	napi_disable(&hw->napi);
+	synchronize_irq(hw->pdev->irq);
+	imask = sky2_read32(hw, B0_IMSK);
 	sky2_write32(hw, B0_IMSK, 0);
+
+	for (i = 0; i < hw->ports; i++) {
+		struct net_device *dev = hw->dev[i];
+		struct sky2_port *sky2 = netdev_priv(dev);
+
+		if (!netif_running(dev))
+			continue;
+
+		netif_carrier_off(dev);
+		netif_tx_disable(dev);
+		sky2_hw_down(sky2);
+	}
+
 	sky2_reset(hw);
-	sky2_write32(hw, B0_IMSK, Y2_IS_BASE);
-	napi_enable(&hw->napi);
 
-	for (i = 0; i < hw->ports; i++)
-		sky2_reattach(hw->dev[i]);
+	for (i = 0; i < hw->ports; i++) {
+		struct net_device *dev = hw->dev[i];
+		struct sky2_port *sky2 = netdev_priv(dev);
+
+		if (!netif_running(dev))
+			continue;
+
+		sky2_hw_up(sky2);
+		netif_wake_queue(dev);
+	}
+
+	sky2_write32(hw, B0_IMSK, imask);
+	sky2_read32(hw, B0_IMSK);
+
+	sky2_read32(hw, B0_Y2_SP_LISR);
+	napi_enable(&hw->napi);
 
 	rtnl_unlock();
 }