[PATCH net 5/7] net: stmmac: fix incorrect GMAC_VLAN_TAG register writting implementation

Ong Boon Leong boon.leong.ong at intel.com
Mon Jan 13 18:01:14 PST 2020


From: "Tan, Tee Min" <tee.min.tan at intel.com>

It should always do a read of current value of GMAC_VLAN_TAG instead of
directly overwriting the register value.

Fixes: c1be0022df0d ("net: stmmac: Add VLAN HASH filtering support in GMAC4+")

Signed-off-by: Tan, Tee Min <tee.min.tan at intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong at intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
index 40ca00e..6e3d0ab 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
@@ -736,11 +736,14 @@ static void dwmac4_update_vlan_hash(struct mac_device_info *hw, u32 hash,
 				    __le16 perfect_match, bool is_double)
 {
 	void __iomem *ioaddr = hw->pcsr;
+	u32 value;
 
 	writel(hash, ioaddr + GMAC_VLAN_HASH_TABLE);
 
+	value = readl(ioaddr + GMAC_VLAN_TAG);
+
 	if (hash) {
-		u32 value = GMAC_VLAN_VTHM | GMAC_VLAN_ETV;
+		value |= GMAC_VLAN_VTHM | GMAC_VLAN_ETV;
 		if (is_double) {
 			value |= GMAC_VLAN_EDVLP;
 			value |= GMAC_VLAN_ESVL;
@@ -759,8 +762,6 @@ static void dwmac4_update_vlan_hash(struct mac_device_info *hw, u32 hash,
 
 		writel(value | perfect_match, ioaddr + GMAC_VLAN_TAG);
 	} else {
-		u32 value = readl(ioaddr + GMAC_VLAN_TAG);
-
 		value &= ~(GMAC_VLAN_VTHM | GMAC_VLAN_ETV);
 		value &= ~(GMAC_VLAN_EDVLP | GMAC_VLAN_ESVL);
 		value &= ~GMAC_VLAN_DOVLTC;
-- 
2.7.4




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