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From:   Ong Boon Leong <boon.leong.ong@intel.com>
To:     netdev@vger.kernel.org
Cc:     Jakub Kicinski <kubakici@wp.pl>,
        Jose Abreu <Jose.Abreu@synopsys.com>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        "David S . Miller" <davem@davemloft.net>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Ong Boon Leong <boon.leong.ong@intel.com>,
        Tan Tee Min <tee.min.tan@intel.com>,
        Voon Weifeng <weifeng.voon@intel.com>,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH net v2 2/4] net: stmmac: fix incorrect GMAC_VLAN_TAG register writting implementation
Date:   Wed, 15 Jan 2020 15:10:01 +0800
Message-Id: <20200115071003.42820-3-boon.leong.ong@intel.com>
In-Reply-To: <20200115071003.42820-1-boon.leong.ong@intel.com>
References: <20200115071003.42820-1-boon.leong.ong@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: "Tan, Tee Min" <tee.min.tan@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@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@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 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