net: stmmac: xgmac: fix incorrect XGMAC_VLAN_TAG register writting

We should always do a read of current value of XGMAC_VLAN_TAG instead of
directly overwriting the register value.

Fixes: 3cd1cfcba26e2 ("net: stmmac: Implement VLAN Hash Filtering in XGMAC")
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index 2af3ac5..a0e67d1 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -569,7 +569,9 @@ static void dwxgmac2_update_vlan_hash(struct mac_device_info *hw, u32 hash,
 
                writel(value, ioaddr + XGMAC_PACKET_FILTER);
 
-               value = XGMAC_VLAN_VTHM | XGMAC_VLAN_ETV;
+               value = readl(ioaddr + XGMAC_VLAN_TAG);
+
+               value |= XGMAC_VLAN_VTHM | XGMAC_VLAN_ETV;
                if (is_double) {
                        value |= XGMAC_VLAN_EDVLP;
                        value |= XGMAC_VLAN_ESVL;
@@ -584,7 +586,9 @@ static void dwxgmac2_update_vlan_hash(struct mac_device_info *hw, u32 hash,
 
                writel(value, ioaddr + XGMAC_PACKET_FILTER);
 
-               value = XGMAC_VLAN_ETV;
+               value = readl(ioaddr + XGMAC_VLAN_TAG);
+
+               value |= XGMAC_VLAN_ETV;
                if (is_double) {
                        value |= XGMAC_VLAN_EDVLP;
                        value |= XGMAC_VLAN_ESVL;