net: stmmac: Add support for VLAN promiscuous mode

For dwmac4, enable VLAN promiscuity when MAC controller is requested to
enter promiscuous mode.

Signed-off-by: Chuah, Kim Tatt <[e-mail]>
Signed-off-by: Ong Boon Leong <[e-mail]>
Signed-off-by: Tan, Tee Min <[e-mail]>
Signed-off-by: Wong Vee Khee <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

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

···
 	unsigned int xlgmac;
 	unsigned int num_vlan;
 	u32 vlan_filter[32];
+	unsigned int promisc;
 };
 
 struct stmmac_rx_routing {

drivers/net/ethernet/stmicro/stmmac/dwmac4.h

···
 #define GMAC_VLAN_CSVL			BIT(19)
 #define GMAC_VLAN_VLC			GENMASK(17, 16)
 #define GMAC_VLAN_VLC_SHIFT		16
+#define GMAC_VLAN_VLHT			GENMASK(15, 0)
 
 /* MAC VLAN Tag */
 #define GMAC_VLAN_TAG_VID		GENMASK(15, 0)

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

···
 	if (vid > 4095)
 		return -EINVAL;
 
+	if (hw->promisc) {
+		netdev_err(dev,
+			   "Adding VLAN in promisc mode not supported\n");
+		return -EPERM;
+	}
+
 	/* Single Rx VLAN Filter */
 	if (hw->num_vlan == 1) {
 		/* For single VLAN filter, VID 0 means VLAN promiscuous */
···
 {
 	int i, ret = 0;
 
+	if (hw->promisc) {
+		netdev_err(dev,
+			   "Deleting VLAN in promisc mode not supported\n");
+		return -EPERM;
+	}
+
 	/* Single Rx VLAN Filter */
 	if (hw->num_vlan == 1) {
 		if ((hw->vlan_filter[0] & GMAC_VLAN_TAG_VID) == vid) {
···
 	return ret;
 }
 
+static void dwmac4_vlan_promisc_enable(struct net_device *dev,
+				       struct mac_device_info *hw)
+{
+	void __iomem *ioaddr = hw->pcsr;
+	u32 value;
+	u32 hash;
+	u32 val;
+	int i;
+
+	/* Single Rx VLAN Filter */
+	if (hw->num_vlan == 1) {
+		dwmac4_write_single_vlan(dev, 0);
+		return;
+	}
+
+	/* Extended Rx VLAN Filter Enable */
+	for (i = 0; i < hw->num_vlan; i++) {
+		if (hw->vlan_filter[i] & GMAC_VLAN_TAG_DATA_VEN) {
+			val = hw->vlan_filter[i] & ~GMAC_VLAN_TAG_DATA_VEN;
+			dwmac4_write_vlan_filter(dev, hw, i, val);
+		}
+	}
+
+	hash = readl(ioaddr + GMAC_VLAN_HASH_TABLE);
+	if (hash & GMAC_VLAN_VLHT) {
+		value = readl(ioaddr + GMAC_VLAN_TAG);
+		if (value & GMAC_VLAN_VTHM) {
+			value &= ~GMAC_VLAN_VTHM;
+			writel(value, ioaddr + GMAC_VLAN_TAG);
+		}
+	}
+}
+
 static void dwmac4_restore_hw_vlan_rx_fltr(struct net_device *dev,
 					   struct mac_device_info *hw)
 {
+	void __iomem *ioaddr = hw->pcsr;
+	u32 value;
+	u32 hash;
 	u32 val;
 	int i;
 
···
 			val = hw->vlan_filter[i];
 			dwmac4_write_vlan_filter(dev, hw, i, val);
 		}
+	}
+
+	hash = readl(ioaddr + GMAC_VLAN_HASH_TABLE);
+	if (hash & GMAC_VLAN_VLHT) {
+		value = readl(ioaddr + GMAC_VLAN_TAG);
+		value |= GMAC_VLAN_VTHM;
+		writel(value, ioaddr + GMAC_VLAN_TAG);
 	}
 }
 
···
 		value |= GMAC_PACKET_FILTER_VTFE;
 
 	writel(value, ioaddr + GMAC_PACKET_FILTER);
+
+	if (dev->flags & IFF_PROMISC) {
+		if (!hw->promisc) {
+			hw->promisc = 1;
+			dwmac4_vlan_promisc_enable(dev, hw);
+		}
+	} else {
+		if (hw->promisc) {
+			hw->promisc = 0;
+			dwmac4_restore_hw_vlan_rx_fltr(dev, hw);
+		}
+	}
 }
 
 static void dwmac4_flow_ctrl(struct mac_device_info *hw, unsigned int duplex,