From e72fd96e8ee3ff4dd80757172a4fe49bd92fea9c Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie@sirena.org.uk>
Date: Thu, 2 Feb 2006 00:00:02 +0000
Subject: [PATCH] natsemi: NAPI and a bugfix
As documented in National application note 1287 the RX state machine on
the natsemi chip can lock up under some conditions (mostly related to
heavy load). When this happens a series of bogus packets are reported
by the chip including some oversized frames prior to the final lockup.
This patch implements the fix from the application note: when an
oversized packet is reported it resets the RX state machine, dropping
any currently pending packets.
Signed-off-by: Mark Brown <broonie@sirena.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
---
drivers/net/natsemi.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
(limited to 'drivers')
diff --git a/drivers/net/natsemi.c b/drivers/net/natsemi.c
index e363f9bb35e..8d4999837b6 100644
--- a/drivers/net/natsemi.c
+++ b/drivers/net/natsemi.c
@@ -1498,6 +1498,31 @@ static void natsemi_reset(struct net_device *dev)
writel(rfcr, ioaddr + RxFilterAddr);
}
+static void reset_rx(struct net_device *dev)
+{
+ int i;
+ struct netdev_private *np = netdev_priv(dev);
+ void __iomem *ioaddr = ns_ioaddr(dev);
+
+ np->intr_status &= ~RxResetDone;
+
+ writel(RxReset, ioaddr + ChipCmd);
+
+ for (i=0;i<NATSEMI_HW_TIMEOUT;i++) {
+ np->intr_status |= readl(ioaddr + IntrStatus);
+ if (np->intr_status & RxResetDone)
+ break;
+ udelay(15);
+ }
+ if (i==NATSEMI_HW_TIMEOUT) {
+ printk(KERN_WARNING "%s: RX reset did not complete in %d usec.\n",
+ dev->name, i*15);
+ } else if (netif_msg_hw(np)) {
+ printk(KERN_WARNING "%s: RX reset took %d usec.\n",
+ dev->name, i*15);
+ }
+}
+
static void natsemi_reload_eeprom(struct net_device *dev)
{
struct netdev_private *np = netdev_priv(dev);
@@ -2292,6 +2317,23 @@ static void netdev_rx(struct net_device *dev, int *work_done, int work_to_do)
"status %#08x.\n", dev->name,
np->cur_rx, desc_status);
np->stats.rx_length_errors++;
+
+ /* The RX state machine has probably
+ * locked up beneath us. Follow the
+ * reset procedure documented in
+ * AN-1287. */
+
+ spin_lock_irq(&np->lock);
+ reset_rx(dev);
+ reinit_rx(dev);
+ writel(np->ring_dma, ioaddr + RxRingPtr);
+ check_link(dev);
+ spin_unlock_irq(&np->lock);
+
+ /* We'll enable RX on exit from this
+ * function. */
+ break;
+
} else {
/* There was an error. */
np->stats.rx_errors++;
--
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