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Commit e72fd96e authored by Mark Brown's avatar Mark Brown Committed by Jeff Garzik
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[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: default avatarMark Brown <broonie@sirena.org.uk>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent b27a16b7

drivers/net/natsemi.c

+42 −0
Original line number Diff line number Diff line
@@ -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++;