net: stmmac: Add support for HW-accelerated VLAN stripping

Current implementation supports driver level VLAN tag stripping only.
The features is always on if CONFIG_VLAN_8021Q is enabled in kernel
config and is not user configurable.

This patch add support to MAC level VLAN tag stripping and can be
configured through ethtool. If the rx-vlan-offload is off, the VLAN tag
will be stripped by driver. If the rx-vlan-offload is on, the VLAN tag
will be stripped by MAC.

Command: ethtool -K <interface> rx-vlan-offload off | on
Signed-off-by: Lai Peter Jun Ann <jun.ann.lai@intel.com>
Signed-off-by: Gan, Yi Fang <yi.fang.gan@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -580,6 +580,7 @@ struct mac_device_info {
 	u32 vlan_filter[32];
 	bool vlan_fail_q_en;
 	u8 vlan_fail_q;
+	bool hw_vlan_en;
 };
 
 struct stmmac_rx_routing {

drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c

@@ -1134,6 +1134,35 @@ static int dwmac4_config_l4_filter(struct mac_device_info *hw, u32 filter_no,
 	return 0;
 }
 
+static void dwmac4_rx_hw_vlan(struct mac_device_info *hw,
+			      struct dma_desc *rx_desc, struct sk_buff *skb)
+{
+	if (hw->desc->get_rx_vlan_valid(rx_desc)) {
+		u16 vid = hw->desc->get_rx_vlan_tci(rx_desc);
+
+		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vid);
+	}
+}
+
+static void dwmac4_set_hw_vlan_mode(struct mac_device_info *hw)
+{
+	void __iomem *ioaddr = hw->pcsr;
+	u32 value = readl(ioaddr + GMAC_VLAN_TAG);
+
+	value &= ~GMAC_VLAN_TAG_CTRL_EVLS_MASK;
+
+	if (hw->hw_vlan_en)
+		/* Always strip VLAN on Receive */
+		value |= GMAC_VLAN_TAG_STRIP_ALL;
+	else
+		/* Do not strip VLAN on Receive */
+		value |= GMAC_VLAN_TAG_STRIP_NONE;
+
+	/* Enable outer VLAN Tag in Rx DMA descriptor */
+	value |= GMAC_VLAN_TAG_CTRL_EVLRXS;
+	writel(value, ioaddr + GMAC_VLAN_TAG);
+}
+
 const struct stmmac_ops dwmac4_ops = {
 	.core_init = dwmac4_core_init,
 	.phylink_get_caps = dwmac4_phylink_get_caps,
@@ -1175,6 +1204,8 @@ const struct stmmac_ops dwmac4_ops = {
 	.add_hw_vlan_rx_fltr = dwmac4_add_hw_vlan_rx_fltr,
 	.del_hw_vlan_rx_fltr = dwmac4_del_hw_vlan_rx_fltr,
 	.restore_hw_vlan_rx_fltr = dwmac4_restore_hw_vlan_rx_fltr,
+	.rx_hw_vlan = dwmac4_rx_hw_vlan,
+	.set_hw_vlan_mode = dwmac4_set_hw_vlan_mode,
 };
 
 const struct stmmac_ops dwmac410_ops = {
@@ -1224,6 +1255,8 @@ const struct stmmac_ops dwmac410_ops = {
 	.add_hw_vlan_rx_fltr = dwmac4_add_hw_vlan_rx_fltr,
 	.del_hw_vlan_rx_fltr = dwmac4_del_hw_vlan_rx_fltr,
 	.restore_hw_vlan_rx_fltr = dwmac4_restore_hw_vlan_rx_fltr,
+	.rx_hw_vlan = dwmac4_rx_hw_vlan,
+	.set_hw_vlan_mode = dwmac4_set_hw_vlan_mode,
 };
 
 const struct stmmac_ops dwmac510_ops = {
@@ -1277,6 +1310,8 @@ const struct stmmac_ops dwmac510_ops = {
 	.add_hw_vlan_rx_fltr = dwmac4_add_hw_vlan_rx_fltr,
 	.del_hw_vlan_rx_fltr = dwmac4_del_hw_vlan_rx_fltr,
 	.restore_hw_vlan_rx_fltr = dwmac4_restore_hw_vlan_rx_fltr,
+	.rx_hw_vlan = dwmac4_rx_hw_vlan,
+	.set_hw_vlan_mode = dwmac4_set_hw_vlan_mode,
 };
 
 static u32 dwmac4_get_num_vlan(void __iomem *ioaddr)

drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c

@@ -198,6 +198,17 @@ static int dwmac4_get_tx_ls(struct dma_desc *p)
 		>> TDES3_LAST_DESCRIPTOR_SHIFT;
 }
 
+static u16 dwmac4_wrback_get_rx_vlan_tci(struct dma_desc *p)
+{
+	return (le32_to_cpu(p->des0) & RDES0_VLAN_TAG_MASK);
+}
+
+static bool dwmac4_wrback_get_rx_vlan_valid(struct dma_desc *p)
+{
+	return ((le32_to_cpu(p->des3) & RDES3_LAST_DESCRIPTOR) &&
+		(le32_to_cpu(p->des3) & RDES3_RDES0_VALID));
+}
+
 static int dwmac4_wrback_get_rx_frame_len(struct dma_desc *p, int rx_coe)
 {
 	return (le32_to_cpu(p->des3) & RDES3_PACKET_SIZE_MASK);
@@ -551,6 +562,8 @@ const struct stmmac_desc_ops dwmac4_desc_ops = {
 	.set_tx_owner = dwmac4_set_tx_owner,
 	.set_rx_owner = dwmac4_set_rx_owner,
 	.get_tx_ls = dwmac4_get_tx_ls,
+	.get_rx_vlan_tci = dwmac4_wrback_get_rx_vlan_tci,
+	.get_rx_vlan_valid = dwmac4_wrback_get_rx_vlan_valid,
 	.get_rx_frame_len = dwmac4_wrback_get_rx_frame_len,
 	.enable_tx_timestamp = dwmac4_rd_enable_tx_timestamp,
 	.get_tx_timestamp_status = dwmac4_wrback_get_tx_timestamp_status,

drivers/net/ethernet/stmicro/stmmac/hwif.h

@@ -56,6 +56,10 @@ struct stmmac_desc_ops {
 	void (*set_tx_ic)(struct dma_desc *p);
 	/* Last tx segment reports the transmit status */
 	int (*get_tx_ls)(struct dma_desc *p);
+	/* Get the tag of the descriptor */
+	u16 (*get_rx_vlan_tci)(struct dma_desc *p);
+	/* Get the valid status of descriptor */
+	bool (*get_rx_vlan_valid)(struct dma_desc *p);
 	/* Return the transmit status looking at the TDES1 */
 	int (*tx_status)(struct stmmac_extra_stats *x,
 			 struct dma_desc *p, void __iomem *ioaddr);
@@ -117,6 +121,10 @@ struct stmmac_desc_ops {
 	stmmac_do_void_callback(__priv, desc, set_tx_ic, __args)
 #define stmmac_get_tx_ls(__priv, __args...) \
 	stmmac_do_callback(__priv, desc, get_tx_ls, __args)
+#define stmmac_get_rx_vlan_tci(__priv, __args...) \
+	stmmac_do_callback(__priv, desc, get_rx_vlan_tci, __args)
+#define stmmac_get_rx_vlan_valid(__priv, __args...) \
+	stmmac_do_callback(__priv, desc, get_rx_vlan_valid, __args)
 #define stmmac_tx_status(__priv, __args...) \
 	stmmac_do_callback(__priv, desc, tx_status, __args)
 #define stmmac_get_tx_len(__priv, __args...) \
@@ -388,6 +396,9 @@ struct stmmac_ops {
 	void (*update_vlan_hash)(struct mac_device_info *hw, u32 hash,
 				 __le16 perfect_match, bool is_double);
 	void (*enable_vlan)(struct mac_device_info *hw, u32 type);
+	void (*rx_hw_vlan)(struct mac_device_info *hw, struct dma_desc *rx_desc,
+			   struct sk_buff *skb);
+	void (*set_hw_vlan_mode)(struct mac_device_info *hw);
 	int (*add_hw_vlan_rx_fltr)(struct net_device *dev,
 				   struct mac_device_info *hw,
 				   __be16 proto, u16 vid);
@@ -497,6 +508,10 @@ struct stmmac_ops {
 	stmmac_do_void_callback(__priv, mac, update_vlan_hash, __args)
 #define stmmac_enable_vlan(__priv, __args...) \
 	stmmac_do_void_callback(__priv, mac, enable_vlan, __args)
+#define stmmac_rx_hw_vlan(__priv, __args...) \
+	stmmac_do_void_callback(__priv, mac, rx_hw_vlan, __args)
+#define stmmac_set_hw_vlan_mode(__priv, __args...) \
+	stmmac_do_void_callback(__priv, mac, set_hw_vlan_mode, __args)
 #define stmmac_add_hw_vlan_rx_fltr(__priv, __args...) \
 	stmmac_do_callback(__priv, mac, add_hw_vlan_rx_fltr, __args)
 #define stmmac_del_hw_vlan_rx_fltr(__priv, __args...) \

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -3469,6 +3469,8 @@ static int stmmac_hw_setup(struct net_device *dev, bool ptp_register)
 	/* Start the ball rolling... */
 	stmmac_start_all_dma(priv);
 
+	stmmac_set_hw_vlan_mode(priv, priv->hw);
+
 	if (priv->dma_cap.fpesel) {
 		stmmac_fpe_start_wq(priv);
 
@@ -4993,7 +4995,12 @@ static void stmmac_dispatch_skb_zc(struct stmmac_priv *priv, u32 queue,
 	}
 
 	stmmac_get_rx_hwtstamp(priv, p, np, skb);
-	stmmac_rx_vlan(priv->dev, skb);
+	if (priv->hw->hw_vlan_en)
+		/* MAC level stripping. */
+		stmmac_rx_hw_vlan(priv, priv->hw, p, skb);
+	else
+		/* Driver level stripping. */
+		stmmac_rx_vlan(priv->dev, skb);
 	skb->protocol = eth_type_trans(skb, priv->dev);
 
 	if (unlikely(!coe))
@@ -5509,7 +5516,14 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 		/* Got entire packet into SKB. Finish it. */
 
 		stmmac_get_rx_hwtstamp(priv, p, np, skb);
-		stmmac_rx_vlan(priv->dev, skb);
+
+		if (priv->hw->hw_vlan_en)
+			/* MAC level stripping. */
+			stmmac_rx_hw_vlan(priv, priv->hw, p, skb);
+		else
+			/* Driver level stripping. */
+			stmmac_rx_vlan(priv->dev, skb);
+
 		skb->protocol = eth_type_trans(skb, priv->dev);
 
 		if (unlikely(!coe))
@@ -5818,6 +5832,13 @@ static int stmmac_set_features(struct net_device *netdev,
 			stmmac_enable_sph(priv, priv->ioaddr, sph_en, chan);
 	}
 
+	if (features & NETIF_F_HW_VLAN_CTAG_RX)
+		priv->hw->hw_vlan_en = true;
+	else
+		priv->hw->hw_vlan_en = false;
+
+	stmmac_set_hw_vlan_mode(priv, priv->hw);
+
 	return 0;
 }
 
@@ -7509,6 +7530,9 @@ int stmmac_dvr_probe(struct device *device,
 #ifdef STMMAC_VLAN_TAG_USED
 	/* Both mac100 and gmac support receive VLAN tag detection */
 	ndev->features |= NETIF_F_HW_VLAN_CTAG_RX | NETIF_F_HW_VLAN_STAG_RX;
+	ndev->hw_features |= NETIF_F_HW_VLAN_CTAG_RX;
+	priv->hw->hw_vlan_en = true;
+
 	if (priv->dma_cap.vlhash) {
 		ndev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
 		ndev->features |= NETIF_F_HW_VLAN_STAG_FILTER;