net: mediatek: fix mtk_pending_work

The driver supports 2 MACs. Both run on the same DMA ring. If we hit a TX
timeout we need to stop both netdevs before restarting them again. If we
don't do this, mtk_stop() wont shutdown DMA and the consecutive call to
mtk_open() wont restart DMA and enable IRQs.
Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -1432,17 +1432,29 @@ static void mtk_pending_work(struct work_struct *work)
 {
 	struct mtk_mac *mac = container_of(work, struct mtk_mac, pending_work);
 	struct mtk_eth *eth = mac->hw;
-	struct net_device *dev = eth->netdev[mac->id];
-	int err;
+	int err, i;
+	unsigned long restart = 0;
 
 	rtnl_lock();
-	mtk_stop(dev);
 
-	err = mtk_open(dev);
-	if (err) {
-		netif_alert(eth, ifup, dev,
-			    "Driver up/down cycle failed, closing device.\n");
-		dev_close(dev);
+	/* stop all devices to make sure that dma is properly shut down */
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!netif_oper_up(eth->netdev[i]))
+			continue;
+		mtk_stop(eth->netdev[i]);
+		__set_bit(i, &restart);
+	}
+
+	/* restart DMA and enable IRQs */
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!test_bit(i, &restart))
+			continue;
+		err = mtk_open(eth->netdev[i]);
+		if (err) {
+			netif_alert(eth, ifup, eth->netdev[i],
+			      "Driver up/down cycle failed, closing device.\n");
+			dev_close(eth->netdev[i]);
+		}
 	}
 	rtnl_unlock();
 }