[PATCH] sundance: fix DFE-580TX Tx Underrun

Under heavy PCI bus load, ports of the DFE-580TX 4-ethernet port board stop
working, with currently no other cure than a powercycle.  Here is a tested
fix.  By the way, I also fixed some references and attribution.

Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 48 insertions, 14 deletions

diff --git a/drivers/net/sundance.c b/drivers/net/sundance.c
index 5de0554fd7c6..0ab9c38b4a34 100644
--- a/drivers/net/sundance.c
+++ b/drivers/net/sundance.c
@@ -80,7 +80,7 @@
           I/O access could affect performance in ARM-based system
         - Add Linux software VLAN support
         
-        Version LK1.08 (D-Link):
+        Version LK1.08 (Philippe De Muyter phdm@macqel.be):
         - Fix bug of custom mac address 
         (StationAddr register only accept word write) 
 
@@ -91,11 +91,14 @@
         Version LK1.09a (ICPlus):
         - Add the delay time in reading the contents of EEPROM
 
+        Version LK1.10 (Philippe De Muyter phdm@macqel.be):
+        - Make 'unblock interface after Tx underrun' work
+
 */
 
 #define DRV_NAME        "sundance"
-#define DRV_VERSION     "1.01+LK1.09a"
-#define DRV_RELDATE     "10-Jul-2003"
+#define DRV_VERSION     "1.01+LK1.10"
+#define DRV_RELDATE     "28-Oct-2005"
 
 
 /* The user-configurable values.
@@ -263,8 +266,10 @@ IV. Notes
 IVb. References
 
 The Sundance ST201 datasheet, preliminary version.
-http://cesdis.gsfc.nasa.gov/linux/misc/100mbps.html
-http://cesdis.gsfc.nasa.gov/linux/misc/NWay.html
+The Kendin KS8723 datasheet, preliminary version.
+The ICplus IP100 datasheet, preliminary version.
+http://www.scyld.com/expert/100mbps.html
+http://www.scyld.com/expert/NWay.html
 
 IVc. Errata
 
@@ -500,6 +505,25 @@ static int netdev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 static int  netdev_close(struct net_device *dev);
 static struct ethtool_ops ethtool_ops;
 
+static void sundance_reset(struct net_device *dev, unsigned long reset_cmd)
+{
+        struct netdev_private *np = netdev_priv(dev);
+        void __iomem *ioaddr = np->base + ASICCtrl;
+        int countdown;
+
+        /* ST201 documentation states ASICCtrl is a 32bit register */
+        iowrite32 (reset_cmd | ioread32 (ioaddr), ioaddr);
+        /* ST201 documentation states reset can take up to 1 ms */
+        countdown = 10 + 1;
+        while (ioread32 (ioaddr) & (ResetBusy << 16)) {
+                if (--countdown == 0) {
+                        printk(KERN_WARNING "%s : reset not completed !!\n", dev->name);
+                        break;
+                }
+                udelay(100);
+        }
+}
+
 static int __devinit sundance_probe1 (struct pci_dev *pdev,
                                       const struct pci_device_id *ent)
 {
@@ -1190,23 +1214,33 @@ static irqreturn_t intr_handler(int irq, void *dev_instance, struct pt_regs *rgs
                                             ("%s: Transmit status is %2.2x.\n",
                                         dev->name, tx_status);
                                 if (tx_status & 0x1e) {
+                                        if (netif_msg_tx_err(np))
+                                                printk("%s: Transmit error status %4.4x.\n",
+                                                           dev->name, tx_status);
                                         np->stats.tx_errors++;
                                         if (tx_status & 0x10)
                                                 np->stats.tx_fifo_errors++;
                                         if (tx_status & 0x08)
                                                 np->stats.collisions++;
+                                        if (tx_status & 0x04)
+                                                np->stats.tx_fifo_errors++;
                                         if (tx_status & 0x02)
                                                 np->stats.tx_window_errors++;
-                                        /* This reset has not been verified!. */
-                                        if (tx_status & 0x10) { /* Reset the Tx. */
-                                                np->stats.tx_fifo_errors++;
-                                                spin_lock(&np->lock);
-                                                reset_tx(dev);
-                                                spin_unlock(&np->lock);
+                                        /*
+                                        ** This reset has been verified on
+                                        ** DFE-580TX boards ! phdm@macqel.be.
+                                        */
+                                        if (tx_status & 0x10) { /* TxUnderrun */
+                                                unsigned short txthreshold;
+
+                                                txthreshold = ioread16 (ioaddr + TxStartThresh);
+                                                /* Restart Tx FIFO and transmitter */
+                                                sundance_reset(dev, (NetworkReset|FIFOReset|TxReset) << 16);
+                                                iowrite16 (txthreshold, ioaddr + TxStartThresh);
+                                                /* No need to reset the Tx pointer here */
                                         }
-                                        if (tx_status & 0x1e)   /* Restart the Tx. */
-                                                iowrite16 (TxEnable,
-                                                        ioaddr + MACCtrl1);
+                                        /* Restart the Tx. */
+                                        iowrite16 (TxEnable, ioaddr + MACCtrl1);
                                 }
                                 /* Yup, this is a documentation bug.  It cost me *hours*. */
                                 iowrite16 (0, ioaddr + TxStatus);