nfp: support LSO2 capability

Firmware advertising the LSO2 capability exploits driver provided L3 and L4
offsets in order to avoid parsing packet headers in the TX path. The vlan
field in struct nfp_net_tx_desc is repurposed, making TXVLAN a mutually
exclusive configuration to LSO2.
Signed-off-by: Edwin Peer <edwin.peer@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net.h

@@ -155,8 +155,13 @@ struct nfp_net_tx_desc {
 			__le16 mss;	/* MSS to be used for LSO */
 			u8 lso_hdrlen;	/* LSO, TCP payload offset */
 			u8 flags;	/* TX Flags, see @PCIE_DESC_TX_* */
-
-			__le16 vlan;	/* VLAN tag to add if indicated */
+			union {
+				struct {
+					u8 l3_offset; /* L3 header offset */
+					u8 l4_offset; /* L4 header offset */
+				};
+				__le16 vlan; /* VLAN tag to add if indicated */
+			};
 			__le16 data_len; /* Length of frame + meta data */
 		} __packed;
 		__le32 vals[4];

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -667,11 +667,16 @@ static void nfp_net_tx_tso(struct nfp_net_r_vector *r_vec,
 	if (!skb_is_gso(skb))
 		return;
 
-	if (!skb->encapsulation)
+	if (!skb->encapsulation) {
+		txd->l3_offset = skb_network_offset(skb);
+		txd->l4_offset = skb_transport_offset(skb);
 		hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
-	else
+	} else {
+		txd->l3_offset = skb_inner_network_offset(skb);
+		txd->l4_offset = skb_inner_transport_offset(skb);
 		hdrlen = skb_inner_transport_header(skb) - skb->data +
 			inner_tcp_hdrlen(skb);
+	}
 
 	txbuf->pkt_cnt = skb_shinfo(skb)->gso_segs;
 	txbuf->real_len += hdrlen * (txbuf->pkt_cnt - 1);
@@ -825,10 +830,9 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
 	txd->mss = 0;
 	txd->lso_hdrlen = 0;
 
+	/* Do not reorder - tso may adjust pkt cnt, vlan may override fields */
 	nfp_net_tx_tso(r_vec, txbuf, txd, skb);
-
 	nfp_net_tx_csum(dp, r_vec, txbuf, txd, skb);
-
 	if (skb_vlan_tag_present(skb) && dp->ctrl & NFP_NET_CFG_CTRL_TXVLAN) {
 		txd->flags |= PCIE_DESC_TX_VLAN;
 		txd->vlan = cpu_to_le16(skb_vlan_tag_get(skb));
@@ -2724,9 +2728,10 @@ static int nfp_net_set_features(struct net_device *netdev,
 
 	if (changed & (NETIF_F_TSO | NETIF_F_TSO6)) {
 		if (features & (NETIF_F_TSO | NETIF_F_TSO6))
-			new_ctrl |= NFP_NET_CFG_CTRL_LSO;
+			new_ctrl |= nn->cap & NFP_NET_CFG_CTRL_LSO2 ?:
+					      NFP_NET_CFG_CTRL_LSO;
 		else
-			new_ctrl &= ~NFP_NET_CFG_CTRL_LSO;
+			new_ctrl &= ~NFP_NET_CFG_CTRL_LSO_ANY;
 	}
 
 	if (changed & NETIF_F_HW_VLAN_CTAG_RX) {
@@ -3032,7 +3037,7 @@ void nfp_net_info(struct nfp_net *nn)
 		nn->fw_ver.resv, nn->fw_ver.class,
 		nn->fw_ver.major, nn->fw_ver.minor,
 		nn->max_mtu);
-	nn_info(nn, "CAP: %#x %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
+	nn_info(nn, "CAP: %#x %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
 		nn->cap,
 		nn->cap & NFP_NET_CFG_CTRL_PROMISC  ? "PROMISC "  : "",
 		nn->cap & NFP_NET_CFG_CTRL_L2BC     ? "L2BCFILT " : "",
@@ -3043,7 +3048,8 @@ void nfp_net_info(struct nfp_net *nn)
 		nn->cap & NFP_NET_CFG_CTRL_TXVLAN   ? "TXVLAN "   : "",
 		nn->cap & NFP_NET_CFG_CTRL_SCATTER  ? "SCATTER "  : "",
 		nn->cap & NFP_NET_CFG_CTRL_GATHER   ? "GATHER "   : "",
-		nn->cap & NFP_NET_CFG_CTRL_LSO      ? "TSO "      : "",
+		nn->cap & NFP_NET_CFG_CTRL_LSO      ? "TSO1 "     : "",
+		nn->cap & NFP_NET_CFG_CTRL_LSO2     ? "TSO2 "     : "",
 		nn->cap & NFP_NET_CFG_CTRL_RSS      ? "RSS "      : "",
 		nn->cap & NFP_NET_CFG_CTRL_L2SWITCH ? "L2SWITCH " : "",
 		nn->cap & NFP_NET_CFG_CTRL_MSIXAUTO ? "AUTOMASK " : "",
@@ -3249,9 +3255,11 @@ int nfp_net_netdev_init(struct net_device *netdev)
 		netdev->hw_features |= NETIF_F_SG;
 		nn->dp.ctrl |= NFP_NET_CFG_CTRL_GATHER;
 	}
-	if ((nn->cap & NFP_NET_CFG_CTRL_LSO) && nn->fw_ver.major > 2) {
+	if ((nn->cap & NFP_NET_CFG_CTRL_LSO && nn->fw_ver.major > 2) ||
+	    nn->cap & NFP_NET_CFG_CTRL_LSO2) {
 		netdev->hw_features |= NETIF_F_TSO | NETIF_F_TSO6;
-		nn->dp.ctrl |= NFP_NET_CFG_CTRL_LSO;
+		nn->dp.ctrl |= nn->cap & NFP_NET_CFG_CTRL_LSO2 ?:
+					 NFP_NET_CFG_CTRL_LSO;
 	}
 	if (nn->cap & NFP_NET_CFG_CTRL_RSS) {
 		netdev->hw_features |= NETIF_F_RXHASH;
@@ -3275,8 +3283,12 @@ int nfp_net_netdev_init(struct net_device *netdev)
 		nn->dp.ctrl |= NFP_NET_CFG_CTRL_RXVLAN;
 	}
 	if (nn->cap & NFP_NET_CFG_CTRL_TXVLAN) {
-		netdev->hw_features |= NETIF_F_HW_VLAN_CTAG_TX;
-		nn->dp.ctrl |= NFP_NET_CFG_CTRL_TXVLAN;
+		if (nn->cap & NFP_NET_CFG_CTRL_LSO2) {
+			nn_warn(nn, "Device advertises both TSO2 and TXVLAN. Refusing to enable TXVLAN.\n");
+		} else {
+			netdev->hw_features |= NETIF_F_HW_VLAN_CTAG_TX;
+			nn->dp.ctrl |= NFP_NET_CFG_CTRL_TXVLAN;
+		}
 	}
 
 	netdev->features = netdev->hw_features;
@@ -3286,7 +3298,7 @@ int nfp_net_netdev_init(struct net_device *netdev)
 
 	/* Advertise but disable TSO by default. */
 	netdev->features &= ~(NETIF_F_TSO | NETIF_F_TSO6);
-	nn->dp.ctrl &= ~NFP_NET_CFG_CTRL_LSO;
+	nn->dp.ctrl &= ~NFP_NET_CFG_CTRL_LSO_ANY;
 
 	/* Allow L2 Broadcast and Multicast through by default, if supported */
 	if (nn->cap & NFP_NET_CFG_CTRL_L2BC)

drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h

@@ -119,7 +119,7 @@
 #define   NFP_NET_CFG_CTRL_TXVLAN         (0x1 <<  7) /* Enable VLAN insert */
 #define   NFP_NET_CFG_CTRL_SCATTER        (0x1 <<  8) /* Scatter DMA */
 #define   NFP_NET_CFG_CTRL_GATHER         (0x1 <<  9) /* Gather DMA */
-#define   NFP_NET_CFG_CTRL_LSO            (0x1 << 10) /* LSO/TSO */
+#define   NFP_NET_CFG_CTRL_LSO            (0x1 << 10) /* LSO/TSO (version 1) */
 #define   NFP_NET_CFG_CTRL_RINGCFG        (0x1 << 16) /* Ring runtime changes */
 #define   NFP_NET_CFG_CTRL_RSS            (0x1 << 17) /* RSS */
 #define   NFP_NET_CFG_CTRL_IRQMOD         (0x1 << 18) /* Interrupt moderation */
@@ -131,6 +131,11 @@
 #define   NFP_NET_CFG_CTRL_VXLAN	  (0x1 << 24) /* VXLAN tunnel support */
 #define   NFP_NET_CFG_CTRL_NVGRE	  (0x1 << 25) /* NVGRE tunnel support */
 #define   NFP_NET_CFG_CTRL_BPF		  (0x1 << 27) /* BPF offload capable */
+#define   NFP_NET_CFG_CTRL_LSO2		  (0x1 << 28) /* LSO/TSO (version 2) */
+
+#define NFP_NET_CFG_CTRL_LSO_ANY	(NFP_NET_CFG_CTRL_LSO | \
+					 NFP_NET_CFG_CTRL_LSO2)
+
 #define NFP_NET_CFG_UPDATE              0x0004
 #define   NFP_NET_CFG_UPDATE_GEN          (0x1 <<  0) /* General update */
 #define   NFP_NET_CFG_UPDATE_RING         (0x1 <<  1) /* Ring config change */