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authorbroonie@sirena.org.uk <broonie@sirena.org.uk>2007-03-14 15:49:14 -0400
committerJeff Garzik <jeff@garzik.org>2007-03-15 10:59:54 -0400
commit069f8256362b7a17da532f0631cee73b4cfee65b (patch)
treeee8e9e4a3b78de04e15a71a4b4216bfc050b3a8a /drivers/net
parent14fdd90ef2ec1878d6851ec4dd8d5abb2cef098c (diff)
natsemi: Fix NAPI for interrupt sharing
The interrupt status register for the natsemi chips is clear on read and was read unconditionally from both the interrupt and from the NAPI poll routine, meaning that if the interrupt service routine was called (for example, due to a shared interrupt) while a NAPI poll was scheduled interrupts could be missed. This patch fixes that by ensuring that the interrupt status register is only read by the interrupt handler when interrupts are enabled from the chip. It also reverts a workaround for this problem from the netpoll hook and improves the trace for interrupt events. Thanks to Sergei Shtylyov <sshtylyov@ru.mvista.com> for spotting the issue, Mark Huth <mhuth@mvista.com> for a simpler method and Simon Blake <simon@citylink.co.nz> for testing resources. Signed-Off-By: Mark Brown <broonie@sirena.org.uk> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/natsemi.c38
1 files changed, 20 insertions, 18 deletions
diff --git a/drivers/net/natsemi.c b/drivers/net/natsemi.c
index 2888880df3b7..5f88200724e6 100644
--- a/drivers/net/natsemi.c
+++ b/drivers/net/natsemi.c
@@ -2119,28 +2119,35 @@ static irqreturn_t intr_handler(int irq, void *dev_instance)
2119 struct netdev_private *np = netdev_priv(dev); 2119 struct netdev_private *np = netdev_priv(dev);
2120 void __iomem * ioaddr = ns_ioaddr(dev); 2120 void __iomem * ioaddr = ns_ioaddr(dev);
2121 2121
2122 if (np->hands_off) 2122 /* Reading IntrStatus automatically acknowledges so don't do
2123 * that while interrupts are disabled, (for example, while a
2124 * poll is scheduled). */
2125 if (np->hands_off || !readl(ioaddr + IntrEnable))
2123 return IRQ_NONE; 2126 return IRQ_NONE;
2124 2127
2125 /* Reading automatically acknowledges. */
2126 np->intr_status = readl(ioaddr + IntrStatus); 2128 np->intr_status = readl(ioaddr + IntrStatus);
2127 2129
2130 if (!np->intr_status)
2131 return IRQ_NONE;
2132
2128 if (netif_msg_intr(np)) 2133 if (netif_msg_intr(np))
2129 printk(KERN_DEBUG 2134 printk(KERN_DEBUG
2130 "%s: Interrupt, status %#08x, mask %#08x.\n", 2135 "%s: Interrupt, status %#08x, mask %#08x.\n",
2131 dev->name, np->intr_status, 2136 dev->name, np->intr_status,
2132 readl(ioaddr + IntrMask)); 2137 readl(ioaddr + IntrMask));
2133 2138
2134 if (!np->intr_status)
2135 return IRQ_NONE;
2136
2137 prefetch(&np->rx_skbuff[np->cur_rx % RX_RING_SIZE]); 2139 prefetch(&np->rx_skbuff[np->cur_rx % RX_RING_SIZE]);
2138 2140
2139 if (netif_rx_schedule_prep(dev)) { 2141 if (netif_rx_schedule_prep(dev)) {
2140 /* Disable interrupts and register for poll */ 2142 /* Disable interrupts and register for poll */
2141 natsemi_irq_disable(dev); 2143 natsemi_irq_disable(dev);
2142 __netif_rx_schedule(dev); 2144 __netif_rx_schedule(dev);
2143 } 2145 } else
2146 printk(KERN_WARNING
2147 "%s: Ignoring interrupt, status %#08x, mask %#08x.\n",
2148 dev->name, np->intr_status,
2149 readl(ioaddr + IntrMask));
2150
2144 return IRQ_HANDLED; 2151 return IRQ_HANDLED;
2145} 2152}
2146 2153
@@ -2156,6 +2163,12 @@ static int natsemi_poll(struct net_device *dev, int *budget)
2156 int work_done = 0; 2163 int work_done = 0;
2157 2164
2158 do { 2165 do {
2166 if (netif_msg_intr(np))
2167 printk(KERN_DEBUG
2168 "%s: Poll, status %#08x, mask %#08x.\n",
2169 dev->name, np->intr_status,
2170 readl(ioaddr + IntrMask));
2171
2159 if (np->intr_status & 2172 if (np->intr_status &
2160 (IntrTxDone | IntrTxIntr | IntrTxIdle | IntrTxErr)) { 2173 (IntrTxDone | IntrTxIntr | IntrTxIdle | IntrTxErr)) {
2161 spin_lock(&np->lock); 2174 spin_lock(&np->lock);
@@ -2399,19 +2412,8 @@ static struct net_device_stats *get_stats(struct net_device *dev)
2399#ifdef CONFIG_NET_POLL_CONTROLLER 2412#ifdef CONFIG_NET_POLL_CONTROLLER
2400static void natsemi_poll_controller(struct net_device *dev) 2413static void natsemi_poll_controller(struct net_device *dev)
2401{ 2414{
2402 struct netdev_private *np = netdev_priv(dev);
2403
2404 disable_irq(dev->irq); 2415 disable_irq(dev->irq);
2405 2416 intr_handler(dev->irq, dev);
2406 /*
2407 * A real interrupt might have already reached us at this point
2408 * but NAPI might still haven't called us back. As the interrupt
2409 * status register is cleared by reading, we should prevent an
2410 * interrupt loss in this case...
2411 */
2412 if (!np->intr_status)
2413 intr_handler(dev->irq, dev);
2414
2415 enable_irq(dev->irq); 2417 enable_irq(dev->irq);
2416} 2418}
2417#endif 2419#endif