[PATCH net v2 2/4] net: stmmac: fix incorrect GMAC_VLAN_TAG register writting implementation

From: Ong Boon Leong
Date: Wed Jan 15 2020 - 02:10:54 EST


From: "Tan, Tee Min" <tee.min.tan@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Ong Boon Leong <boon.leong.ong@xxxxxxxxx>
---
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 40ca00e596dd..6e3d0ab0ecd6 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;
--
2.17.1