From 8f24664da64f8db094cd9d379b16fc1d8776d1df Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <shemminger@osdl.org>
Date: Mon, 20 Mar 2006 15:48:21 -0800
Subject: [PATCH] sky2: transmit recovery

This patch decodes state and revovers from any races in the transmit
timeout and NAPI logic. It should never trigger, but if it does then
do the right thing.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
---
 drivers/net/sky2.c | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)

(limited to 'drivers')

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index ffe3aa7e2ab2..ab36a7460a26 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1328,7 +1328,7 @@ static void sky2_tx_complete(struct sky2_port *sky2, u16 done)
 	}
 
 	sky2->tx_cons = put;
-	if (netif_queue_stopped(dev) && tx_avail(sky2) > MAX_SKB_TX_LE)
+	if (tx_avail(sky2) > MAX_SKB_TX_LE)
 		netif_wake_queue(dev);
 }
 
@@ -1651,17 +1651,40 @@ static void sky2_tx_timeout(struct net_device *dev)
 	struct sky2_port *sky2 = netdev_priv(dev);
 	struct sky2_hw *hw = sky2->hw;
 	unsigned txq = txqaddr[sky2->port];
+	u16 report, done;
 
 	if (netif_msg_timer(sky2))
 		printk(KERN_ERR PFX "%s: tx timeout\n", dev->name);
 
-	sky2_write32(hw, Q_ADDR(txq, Q_CSR), BMU_STOP);
-	sky2_write32(hw, Y2_QADDR(txq, PREF_UNIT_CTRL), PREF_UNIT_RST_SET);
+	report = sky2_read16(hw, sky2->port == 0 ? STAT_TXA1_RIDX : STAT_TXA2_RIDX);
+	done = sky2_read16(hw, Q_ADDR(txq, Q_DONE));
 
-	sky2_tx_clean(sky2);
+	printk(KERN_DEBUG PFX "%s: transmit ring %u .. %u report=%u done=%u\n",
+	       dev->name,
+	       sky2->tx_cons, sky2->tx_prod, report, done);
+
+	if (report != done) {
+		printk(KERN_INFO PFX "status burst pending (irq moderation?)\n");
+
+		sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_STOP);
+		sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_START);
+	} else if (report != sky2->tx_cons) {
+		printk(KERN_INFO PFX "status report lost?\n");
 
-	sky2_qset(hw, txq);
-	sky2_prefetch_init(hw, txq, sky2->tx_le_map, TX_RING_SIZE - 1);
+		spin_lock_bh(&sky2->tx_lock);
+		sky2_tx_complete(sky2, report);
+		spin_unlock_bh(&sky2->tx_lock);
+	} else {
+		printk(KERN_INFO PFX "hardware hung? flushing\n");
+
+		sky2_write32(hw, Q_ADDR(txq, Q_CSR), BMU_STOP);
+		sky2_write32(hw, Y2_QADDR(txq, PREF_UNIT_CTRL), PREF_UNIT_RST_SET);
+
+		sky2_tx_clean(sky2);
+
+		sky2_qset(hw, txq);
+		sky2_prefetch_init(hw, txq, sky2->tx_le_map, TX_RING_SIZE - 1);
+	}
 }
 
 
@@ -2097,6 +2120,8 @@ static irqreturn_t sky2_intr(int irq, void *dev_id, struct pt_regs *regs)
 	prefetch(&hw->st_le[hw->st_idx]);
 	if (likely(__netif_rx_schedule_prep(dev0)))
 		__netif_rx_schedule(dev0);
+	else
+		printk(KERN_DEBUG PFX "irq race detected\n");
 
 	return IRQ_HANDLED;
 }
-- 
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