[PATCH net-next 1/3] net: stmmac: Fallback to VLAN Perfect filtering if HASH is not available

[Jose Abreu]

From: Jose Abreu <joabreu@xxxxxxxxxxxx>

If VLAN Hash Filtering is not available we can fallback to perfect
filtering instead. Let's implement this in XGMAC and GMAC cores and let
the user use this filter.

VLAN VID=0 always passes filter so we check if more than 2 VLANs are
created and return proper error code if so because perfect filtering
only supports 1 VID at a time.

Signed-off-by: Jose Abreu <joabreu@xxxxxxxxxxxx>

---
Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
Cc: Jose Abreu <joabreu@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c   | 12 +++++++++++-
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c | 17 ++++++++++++++++-
 drivers/net/ethernet/stmicro/stmmac/hwif.h          |  2 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c   | 18 ++++++++++++------
 4 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
index 5a7b0aca1d31..1a04815d1d65 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
@@ -733,7 +733,7 @@ static void dwmac4_set_mac_loopback(void __iomem *ioaddr, bool enable)
 }
 
 static void dwmac4_update_vlan_hash(struct mac_device_info *hw, u32 hash,
-				    bool is_double)
+				    u16 perfect_match, bool is_double)
 {
 	void __iomem *ioaddr = hw->pcsr;
 
@@ -748,6 +748,16 @@ static void dwmac4_update_vlan_hash(struct mac_device_info *hw, u32 hash,
 		}
 
 		writel(value, ioaddr + GMAC_VLAN_TAG);
+	} else if (perfect_match) {
+		u32 value = GMAC_VLAN_ETV;
+
+		if (is_double) {
+			value |= GMAC_VLAN_EDVLP;
+			value |= GMAC_VLAN_ESVL;
+			value |= GMAC_VLAN_DOVLTC;
+		}
+
+		writel(value | perfect_match, ioaddr + GMAC_VLAN_TAG);
 	} else {
 		u32 value = readl(ioaddr + GMAC_VLAN_TAG);
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index 5031398e612c..5cda360d5d07 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -555,7 +555,7 @@ static int dwxgmac2_rss_configure(struct mac_device_info *hw,
 }
 
 static void dwxgmac2_update_vlan_hash(struct mac_device_info *hw, u32 hash,
-				      bool is_double)
+				      u16 perfect_match, bool is_double)
 {
 	void __iomem *ioaddr = hw->pcsr;
 
@@ -576,6 +576,21 @@ static void dwxgmac2_update_vlan_hash(struct mac_device_info *hw, u32 hash,
 		}
 
 		writel(value, ioaddr + XGMAC_VLAN_TAG);
+	} else if (perfect_match) {
+		u32 value = readl(ioaddr + XGMAC_PACKET_FILTER);
+
+		value |= XGMAC_FILTER_VTFE;
+
+		writel(value, ioaddr + XGMAC_PACKET_FILTER);
+
+		value = XGMAC_VLAN_ETV;
+		if (is_double) {
+			value |= XGMAC_VLAN_EDVLP;
+			value |= XGMAC_VLAN_ESVL;
+			value |= XGMAC_VLAN_DOVLTC;
+		}
+
+		writel(value | perfect_match, ioaddr + XGMAC_VLAN_TAG);
 	} else {
 		u32 value = readl(ioaddr + XGMAC_PACKET_FILTER);
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index ddb851d99618..1303d1e9a18f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -357,7 +357,7 @@ struct stmmac_ops {
 			     struct stmmac_rss *cfg, u32 num_rxq);
 	/* VLAN */
 	void (*update_vlan_hash)(struct mac_device_info *hw, u32 hash,
-				 bool is_double);
+				 u16 perfect_match, bool is_double);
 	void (*enable_vlan)(struct mac_device_info *hw, u32 type);
 	/* TX Timestamp */
 	int (*get_mac_tx_timestamp)(struct mac_device_info *hw, u64 *ts);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b8ac1744950e..8b76745a7ec4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4207,15 +4207,25 @@ static u32 stmmac_vid_crc32_le(__le16 vid_le)
 static int stmmac_vlan_update(struct stmmac_priv *priv, bool is_double)
 {
 	u32 crc, hash = 0;
-	u16 vid;
+	int count = 0;
+	u16 vid = 0;
 
 	for_each_set_bit(vid, priv->active_vlans, VLAN_N_VID) {
 		__le16 vid_le = cpu_to_le16(vid);
 		crc = bitrev32(~stmmac_vid_crc32_le(vid_le)) >> 28;
 		hash |= (1 << crc);
+		count++;
+	}
+
+	if (!priv->dma_cap.vlhash) {
+		if (count > 2) /* VID = 0 always passes filter */
+			return -EOPNOTSUPP;
+
+		vid = cpu_to_le16(vid);
+		hash = 0;
 	}
 
-	return stmmac_update_vlan_hash(priv, priv->hw, hash, is_double);
+	return stmmac_update_vlan_hash(priv, priv->hw, hash, vid, is_double);
 }
 
 static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid)
@@ -4224,8 +4234,6 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
 	bool is_double = false;
 	int ret;
 
-	if (!priv->dma_cap.vlhash)
-		return -EOPNOTSUPP;
 	if (be16_to_cpu(proto) == ETH_P_8021AD)
 		is_double = true;
 
@@ -4244,8 +4252,6 @@ static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vi
 	struct stmmac_priv *priv = netdev_priv(ndev);
 	bool is_double = false;
 
-	if (!priv->dma_cap.vlhash)
-		return -EOPNOTSUPP;
 	if (be16_to_cpu(proto) == ETH_P_8021AD)
 		is_double = true;
 
-- 
2.7.4