netdev - [PATCH v2 net-next] r8169: add random MAC address fallback

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Date:   Tue, 2 Jul 2019 20:46:09 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        David Miller <davem@...emloft.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH v2 net-next] r8169: add random MAC address fallback

It was reported that the GPD MicroPC is broken in a way that no valid
MAC address can be read from the network chip. The vendor driver deals
with this by assigning a random MAC address as fallback. So let's do
the same.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
v2:
- fix broken commit message
---
 drivers/net/ethernet/realtek/r8169_main.c | 40 +++++++++++++++--------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 450c74dc1..d6c137b7f 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -6651,13 +6651,36 @@ static int rtl_get_ether_clk(struct rtl8169_private *tp)
 	return rc;
 }
 
+static void rtl_init_mac_address(struct rtl8169_private *tp)
+{
+	struct net_device *dev = tp->dev;
+	u8 *mac_addr = dev->dev_addr;
+	int rc, i;
+
+	rc = eth_platform_get_mac_address(tp_to_dev(tp), mac_addr);
+	if (!rc)
+		goto done;
+
+	rtl_read_mac_address(tp, mac_addr);
+	if (is_valid_ether_addr(mac_addr))
+		goto done;
+
+	for (i = 0; i < ETH_ALEN; i++)
+		mac_addr[i] = RTL_R8(tp, MAC0 + i);
+	if (is_valid_ether_addr(mac_addr))
+		goto done;
+
+	eth_hw_addr_random(dev);
+	dev_warn(tp_to_dev(tp), "can't read MAC address, setting random one\n");
+done:
+	rtl_rar_set(tp, mac_addr);
+}
+
 static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
-	/* align to u16 for is_valid_ether_addr() */
-	u8 mac_addr[ETH_ALEN] __aligned(2) = {};
 	struct rtl8169_private *tp;
 	struct net_device *dev;
-	int chipset, region, i;
+	int chipset, region;
 	int jumbo_max, rc;
 
 	dev = devm_alloc_etherdev(&pdev->dev, sizeof (*tp));
@@ -6749,16 +6772,7 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	u64_stats_init(&tp->rx_stats.syncp);
 	u64_stats_init(&tp->tx_stats.syncp);
 
-	/* get MAC address */
-	rc = eth_platform_get_mac_address(&pdev->dev, mac_addr);
-	if (rc)
-		rtl_read_mac_address(tp, mac_addr);
-
-	if (is_valid_ether_addr(mac_addr))
-		rtl_rar_set(tp, mac_addr);
-
-	for (i = 0; i < ETH_ALEN; i++)
-		dev->dev_addr[i] = RTL_R8(tp, MAC0 + i);
+	rtl_init_mac_address(tp);
 
 	dev->ethtool_ops = &rtl8169_ethtool_ops;
 
-- 
2.22.0