igbvf: Add support for generic Tx checksums

This patch adds support for generic Tx checksums to the igbvf driver.  It
turns out this is actually pretty easy after going over the datasheet as we
were doing a number of steps we didn't need to.

In order to perform a Tx checksum for an L4 header we need to fill in the
following fields in the Tx descriptor:
  MACLEN (maximum of 127), retrieved from:
		skb_network_offset()
  IPLEN  (maximum of 511), retrieved from:
		skb_checksum_start_offset() - skb_network_offset()
  TUCMD.L4T indicates offset and if checksum or crc32c, based on:
		skb->csum_offset

The added advantage to doing this is that we can support inner checksum
offloads for tunnels and MPLS while still being able to transparently
insert VLAN tags.

I also took the opportunity to clean-up many of the feature flag
configuration bits to make them a bit more consistent between drivers.  In
the case of the VF drivers this meant adding support for SCTP CRCs, and
inner checksum offloads for MPLS and various tunnel types.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igbvf/netdev.c

@@ -43,6 +43,7 @@
 #include <linux/ethtool.h>
 #include <linux/if_vlan.h>
 #include <linux/prefetch.h>
+#include <linux/sctp.h>
 
 #include "igbvf.h"
 
@@ -1908,6 +1909,31 @@ static void igbvf_watchdog_task(struct work_struct *work)
 #define IGBVF_TX_FLAGS_VLAN_MASK	0xffff0000
 #define IGBVF_TX_FLAGS_VLAN_SHIFT	16
 
+static void igbvf_tx_ctxtdesc(struct igbvf_ring *tx_ring, u32 vlan_macip_lens,
+			      u32 type_tucmd, u32 mss_l4len_idx)
+{
+	struct e1000_adv_tx_context_desc *context_desc;
+	struct igbvf_buffer *buffer_info;
+	u16 i = tx_ring->next_to_use;
+
+	context_desc = IGBVF_TX_CTXTDESC_ADV(*tx_ring, i);
+	buffer_info = &tx_ring->buffer_info[i];
+
+	i++;
+	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;
+
+	/* set bits to identify this as an advanced context descriptor */
+	type_tucmd |= E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT;
+
+	context_desc->vlan_macip_lens	= cpu_to_le32(vlan_macip_lens);
+	context_desc->seqnum_seed	= 0;
+	context_desc->type_tucmd_mlhl	= cpu_to_le32(type_tucmd);
+	context_desc->mss_l4len_idx	= cpu_to_le32(mss_l4len_idx);
+
+	buffer_info->time_stamp = jiffies;
+	buffer_info->dma = 0;
+}
+
 static int igbvf_tso(struct igbvf_adapter *adapter,
 		     struct igbvf_ring *tx_ring,
 		     struct sk_buff *skb, u32 tx_flags, u8 *hdr_len,
@@ -1987,65 +2013,56 @@ static int igbvf_tso(struct igbvf_adapter *adapter,
 	return true;
 }
 
-static inline bool igbvf_tx_csum(struct igbvf_adapter *adapter,
-				 struct igbvf_ring *tx_ring,
-				 struct sk_buff *skb, u32 tx_flags,
-				 __be16 protocol)
+static inline bool igbvf_ipv6_csum_is_sctp(struct sk_buff *skb)
 {
-	struct e1000_adv_tx_context_desc *context_desc;
-	unsigned int i;
-	struct igbvf_buffer *buffer_info;
-	u32 info = 0, tu_cmd = 0;
+	unsigned int offset = 0;
 
-	if ((skb->ip_summed == CHECKSUM_PARTIAL) ||
-	    (tx_flags & IGBVF_TX_FLAGS_VLAN)) {
-		i = tx_ring->next_to_use;
-		buffer_info = &tx_ring->buffer_info[i];
-		context_desc = IGBVF_TX_CTXTDESC_ADV(*tx_ring, i);
-
-		if (tx_flags & IGBVF_TX_FLAGS_VLAN)
-			info |= (tx_flags & IGBVF_TX_FLAGS_VLAN_MASK);
+	ipv6_find_hdr(skb, &offset, IPPROTO_SCTP, NULL, NULL);
 
-		info |= (skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT);
-		if (skb->ip_summed == CHECKSUM_PARTIAL)
-			info |= (skb_transport_header(skb) -
-				 skb_network_header(skb));
+	return offset == skb_checksum_start_offset(skb);
+}
 
-		context_desc->vlan_macip_lens = cpu_to_le32(info);
+static bool igbvf_tx_csum(struct igbvf_ring *tx_ring, struct sk_buff *skb,
+			  u32 tx_flags, __be16 protocol)
+{
+	u32 vlan_macip_lens = 0;
+	u32 type_tucmd = 0;
 
-		tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);
+	if (skb->ip_summed != CHECKSUM_PARTIAL) {
+csum_failed:
+		if (!(tx_flags & IGBVF_TX_FLAGS_VLAN))
+			return false;
+		goto no_csum;
+	}
 
-		if (skb->ip_summed == CHECKSUM_PARTIAL) {
-			switch (protocol) {
-			case htons(ETH_P_IP):
-				tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
-				if (ip_hdr(skb)->protocol == IPPROTO_TCP)
-					tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
+	switch (skb->csum_offset) {
+	case offsetof(struct tcphdr, check):
+		type_tucmd = E1000_ADVTXD_TUCMD_L4T_TCP;
+		/* fall through */
+	case offsetof(struct udphdr, check):
 		break;
-			case htons(ETH_P_IPV6):
-				if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
-					tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
-				break;
-			default:
+	case offsetof(struct sctphdr, checksum):
+		/* validate that this is actually an SCTP request */
+		if (((protocol == htons(ETH_P_IP)) &&
+		     (ip_hdr(skb)->protocol == IPPROTO_SCTP)) ||
+		    ((protocol == htons(ETH_P_IPV6)) &&
+		     igbvf_ipv6_csum_is_sctp(skb))) {
+			type_tucmd = E1000_ADVTXD_TUCMD_L4T_SCTP;
 			break;
 		}
+	default:
+		skb_checksum_help(skb);
+		goto csum_failed;
 	}
 
-		context_desc->type_tucmd_mlhl = cpu_to_le32(tu_cmd);
-		context_desc->seqnum_seed = 0;
-		context_desc->mss_l4len_idx = 0;
-
-		buffer_info->time_stamp = jiffies;
-		buffer_info->dma = 0;
-		i++;
-		if (i == tx_ring->count)
-			i = 0;
-		tx_ring->next_to_use = i;
+	vlan_macip_lens = skb_checksum_start_offset(skb) -
+			  skb_network_offset(skb);
+no_csum:
+	vlan_macip_lens |= skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT;
+	vlan_macip_lens |= tx_flags & IGBVF_TX_FLAGS_VLAN_MASK;
 
+	igbvf_tx_ctxtdesc(tx_ring, vlan_macip_lens, type_tucmd, 0);
 	return true;
-	}
-
-	return false;
 }
 
 static int igbvf_maybe_stop_tx(struct net_device *netdev, int size)
@@ -2264,7 +2281,7 @@ static netdev_tx_t igbvf_xmit_frame_ring_adv(struct sk_buff *skb,
 
 	if (tso)
 		tx_flags |= IGBVF_TX_FLAGS_TSO;
-	else if (igbvf_tx_csum(adapter, tx_ring, skb, tx_flags, protocol) &&
+	else if (igbvf_tx_csum(tx_ring, skb, tx_flags, protocol) &&
 		 (skb->ip_summed == CHECKSUM_PARTIAL))
 		tx_flags |= IGBVF_TX_FLAGS_CSUM;
 
@@ -2717,11 +2734,11 @@ static int igbvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	adapter->bd_number = cards_found++;
 
 	netdev->hw_features = NETIF_F_SG |
-			   NETIF_F_IP_CSUM |
-			   NETIF_F_IPV6_CSUM |
 			      NETIF_F_TSO |
 			      NETIF_F_TSO6 |
-			   NETIF_F_RXCSUM;
+			      NETIF_F_RXCSUM |
+			      NETIF_F_HW_CSUM |
+			      NETIF_F_SCTP_CRC;
 
 	netdev->features = netdev->hw_features |
 			   NETIF_F_HW_VLAN_CTAG_TX |
@@ -2731,11 +2748,14 @@ static int igbvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (pci_using_dac)
 		netdev->features |= NETIF_F_HIGHDMA;
 
-	netdev->vlan_features |= NETIF_F_TSO;
-	netdev->vlan_features |= NETIF_F_TSO6;
-	netdev->vlan_features |= NETIF_F_IP_CSUM;
-	netdev->vlan_features |= NETIF_F_IPV6_CSUM;
-	netdev->vlan_features |= NETIF_F_SG;
+	netdev->vlan_features |= NETIF_F_SG |
+				 NETIF_F_TSO |
+				 NETIF_F_TSO6 |
+				 NETIF_F_HW_CSUM |
+				 NETIF_F_SCTP_CRC;
+
+	netdev->mpls_features |= NETIF_F_HW_CSUM;
+	netdev->hw_enc_features |= NETIF_F_HW_CSUM;
 
 	/*reset the controller to put the device in a known good state */
 	err = hw->mac.ops.reset_hw(hw);

drivers/net/ethernet/intel/igbvf/vf.h

@@ -126,6 +126,7 @@ struct e1000_adv_tx_context_desc {
 #define E1000_ADVTXD_MACLEN_SHIFT	9  /* Adv ctxt desc mac len shift */
 #define E1000_ADVTXD_TUCMD_IPV4		0x00000400 /* IP Packet Type: 1=IPv4 */
 #define E1000_ADVTXD_TUCMD_L4T_TCP	0x00000800 /* L4 Packet TYPE of TCP */
+#define E1000_ADVTXD_TUCMD_L4T_SCTP	0x00001000 /* L4 packet TYPE of SCTP */
 #define E1000_ADVTXD_L4LEN_SHIFT	8  /* Adv ctxt L4LEN shift */
 #define E1000_ADVTXD_MSS_SHIFT		16 /* Adv ctxt MSS shift */