net: hns: support deferred probe when no mdio

In the hip06 and hip07 SoCs, phy connect to mdio bus.The mdio
module is probed with module_init, and, as such,
is not guaranteed to probe before the HNS driver. So we need
to support deferred probe.

We check for probe deferral in the mac init, so we not init DSAF
when there is no mdio, and free all resource, to later learn that
we need to defer the probe.
Signed-off-by: Nlipeng <lipeng321@huawei.com>
Reviewed-by: NYisen Zhuang <yisen.zhuang@huawei.com>
Reviewed-by: NMatthias Brugger <mbrugger@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c

@@ -696,6 +696,8 @@ hns_mac_register_phydev(struct mii_bus *mdio, struct hns_mac_cb *mac_cb,
 	rc = phy_device_register(phy);
 	if (rc) {
 		phy_device_free(phy);
+		dev_err(&mdio->dev, "registered phy fail at address %i\n",
+			addr);
 		return -ENODEV;
 	}
 
@@ -706,7 +708,7 @@ hns_mac_register_phydev(struct mii_bus *mdio, struct hns_mac_cb *mac_cb,
 	return 0;
 }
 
-static void hns_mac_register_phy(struct hns_mac_cb *mac_cb)
+static int hns_mac_register_phy(struct hns_mac_cb *mac_cb)
 {
 	struct acpi_reference_args args;
 	struct platform_device *pdev;
@@ -716,24 +718,39 @@ static void hns_mac_register_phy(struct hns_mac_cb *mac_cb)
 
 	/* Loop over the child nodes and register a phy_device for each one */
 	if (!to_acpi_device_node(mac_cb->fw_port))
-		return;
+		return -ENODEV;
 
 	rc = acpi_node_get_property_reference(
 			mac_cb->fw_port, "mdio-node", 0, &args);
 	if (rc)
-		return;
+		return rc;
 
 	addr = hns_mac_phy_parse_addr(mac_cb->dev, mac_cb->fw_port);
 	if (addr < 0)
-		return;
+		return addr;
 
 	/* dev address in adev */
 	pdev = hns_dsaf_find_platform_device(acpi_fwnode_handle(args.adev));
+	if (!pdev) {
+		dev_err(mac_cb->dev, "mac%d mdio pdev is NULL\n",
+			mac_cb->mac_id);
+		return  -EINVAL;
+	}
+
 	mii_bus = platform_get_drvdata(pdev);
+	if (!mii_bus) {
+		dev_err(mac_cb->dev,
+			"mac%d mdio is NULL, dsaf will probe again later\n",
+			mac_cb->mac_id);
+		return -EPROBE_DEFER;
+	}
+
 	rc = hns_mac_register_phydev(mii_bus, mac_cb, addr);
 	if (!rc)
 		dev_dbg(mac_cb->dev, "mac%d register phy addr:%d\n",
 			mac_cb->mac_id, addr);
+
+	return rc;
 }
 
 #define MAC_MEDIA_TYPE_MAX_LEN		16
@@ -754,7 +771,7 @@ static const struct {
  *@np:device node
  * return: 0 --success, negative --fail
  */
-static int  hns_mac_get_info(struct hns_mac_cb *mac_cb)
+static int hns_mac_get_info(struct hns_mac_cb *mac_cb)
 {
 	struct device_node *np;
 	struct regmap *syscon;
@@ -864,7 +881,15 @@ static int  hns_mac_get_info(struct hns_mac_cb *mac_cb)
 			}
 		}
 	} else if (is_acpi_node(mac_cb->fw_port)) {
-		hns_mac_register_phy(mac_cb);
+		ret = hns_mac_register_phy(mac_cb);
+		/*
+		 * Mac can work well if there is phy or not.If the port don't
+		 * connect with phy, the return value will be ignored. Only
+		 * when there is phy but can't find mdio bus, the return value
+		 * will be handled.
+		 */
+		if (ret == -EPROBE_DEFER)
+			return ret;
 	} else {
 		dev_err(mac_cb->dev, "mac%d cannot find phy node\n",
 			mac_cb->mac_id);
@@ -1026,6 +1051,7 @@ int hns_mac_init(struct dsaf_device *dsaf_dev)
 			dsaf_dev->mac_cb[port_id] = mac_cb;
 		}
 	}
+
 	/* init mac_cb for all port */
 	for (port_id = 0; port_id < max_port_num; port_id++) {
 		mac_cb = dsaf_dev->mac_cb[port_id];
@@ -1035,6 +1061,7 @@ int hns_mac_init(struct dsaf_device *dsaf_dev)
 		ret = hns_mac_get_cfg(dsaf_dev, mac_cb);
 		if (ret)
 			return ret;
+
 		ret = hns_mac_init_ex(mac_cb);
 		if (ret)
 			return ret;