net: amd-xgbe: Fix network fluctuations when using 1G BELFUSE SFP

[ Upstream commit 9eab3fdb419916f66a72d1572f68d82cd9b3f963 ]

Frequent link up/down events can happen when a Bel Fuse SFP part is
connected to the amd-xgbe device. Try to avoid the frequent link
issues by resetting the PHY as documented in Bel Fuse SFP datasheets.

Fixes: e722ec82374b ("amd-xgbe: Update the BelFuse quirk to support SGMII")
Co-developed-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
index d3f72fa..18e48b3 100644 (file)
--- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
@@ -922,6 +922,9 @@ static bool xgbe_phy_belfuse_phy_quirks(struct xgbe_prv_data *pdata)
        if ((phy_id & 0xfffffff0) != 0x03625d10)
                return false;
 
+       /* Reset PHY - wait for self-clearing reset bit to clear */
+       genphy_soft_reset(phy_data->phydev);
+
        /* Disable RGMII mode */
        phy_write(phy_data->phydev, 0x18, 0x7007);
        reg = phy_read(phy_data->phydev, 0x18);