[PATCH 5.5 330/367] net: stmmac: fix incorrect GMAC_VLAN_TAG register writting in GMAC4+

Greg Kroah-Hartman
2020-02-10T12:51:00Z

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

[ Upstream commit 9eeeb3c9de4e3aeaa2bec097162f09305dd9f4c3 ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- 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(stru
__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(stru

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;