net: axiemac: add PM callbacks to support suspend/resume

Support basic system-wide suspend and resume functions
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -2217,12 +2217,48 @@ static void axienet_shutdown(struct platform_device *pdev)
 	rtnl_unlock();
 }
 
+static int axienet_suspend(struct device *dev)
+{
+	struct net_device *ndev = dev_get_drvdata(dev);
+
+	if (!netif_running(ndev))
+		return 0;
+
+	netif_device_detach(ndev);
+
+	rtnl_lock();
+	axienet_stop(ndev);
+	rtnl_unlock();
+
+	return 0;
+}
+
+static int axienet_resume(struct device *dev)
+{
+	struct net_device *ndev = dev_get_drvdata(dev);
+
+	if (!netif_running(ndev))
+		return 0;
+
+	rtnl_lock();
+	axienet_open(ndev);
+	rtnl_unlock();
+
+	netif_device_attach(ndev);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(axienet_pm_ops,
+				axienet_suspend, axienet_resume);
+
 static struct platform_driver axienet_driver = {
 	.probe = axienet_probe,
 	.remove = axienet_remove,
 	.shutdown = axienet_shutdown,
 	.driver = {
 		 .name = "xilinx_axienet",
+		 .pm = &axienet_pm_ops,
 		 .of_match_table = axienet_of_match,
 	},
 };