arcnet: add netif_carrier_on/off for reconnect

The arcnet device has no interrupt to detect if the link has changed
from disconnected to connected. This patch adds an timer to toggle the
link detection. The timer will get retriggered as long as the
reconnection interrupts accure. If the recon interrupts hold off
for >1s we define the connection stable again.

Signed-off-by: Michael Grzeschik <[e-mail]>

drivers/net/arcnet/arcdevice.h

···
 	struct led_trigger *recon_led_trig;
 	char recon_led_trig_name[ARCNET_LED_NAME_SZ];
 
+	struct timer_list	timer;
+
 	/*
 	 * Buffer management: an ARCnet card has 4 x 512-byte buffers, each of
 	 * which can be used for either sending or receiving.  The new dynamic

drivers/net/arcnet/arcnet.c

···
 	dev->flags = IFF_BROADCAST;
 }
 
+static void arcnet_timer(unsigned long data)
+{
+	struct net_device *dev = (struct net_device *)data;
+
+	if (!netif_carrier_ok(dev)) {
+		netif_carrier_on(dev);
+		netdev_info(dev, "link up\n");
+	}
+}
+
 struct net_device *alloc_arcdev(const char *name)
 {
 	struct net_device *dev;
···
 		struct arcnet_local *lp = netdev_priv(dev);
 
 		spin_lock_init(&lp->lock);
+		init_timer(&lp->timer);
+		lp->timer.data = (unsigned long) dev;
+		lp->timer.function = arcnet_timer;
 	}
 
 	return dev;
···
 	lp->hw.intmask(dev, lp->intmask);
 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
 
+	netif_carrier_off(dev);
 	netif_start_queue(dev);
+	mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));
 
 	arcnet_led_event(dev, ARCNET_LED_EVENT_OPEN);
 	return 0;
···
 	struct arcnet_local *lp = netdev_priv(dev);
 
 	arcnet_led_event(dev, ARCNET_LED_EVENT_STOP);
+	del_timer_sync(&lp->timer);
+
 	netif_stop_queue(dev);
+	netif_carrier_off(dev);
 
 	/* flush TX and disable RX */
 	lp->hw.intmask(dev, 0);
···
 
 			arc_printk(D_RECON, dev, "Network reconfiguration detected (status=%Xh)\n",
 				   status);
+			if (netif_carrier_ok(dev)) {
+				netif_carrier_off(dev);
+				netdev_info(dev, "link down\n");
+			}
+			mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));
+
 			arcnet_led_event(dev, ARCNET_LED_EVENT_RECON);
 			/* MYRECON bit is at bit 7 of diagstatus */
 			if (diagstatus & 0x80)
···
 			lp->num_recons = lp->network_down = 0;
 
 			arc_printk(D_DURING, dev, "not recon: clearing counters anyway.\n");
+			netif_carrier_on(dev);
 		}
 
 		if (didsomething)