s390/qeth: add IPv6 TX checksum offload support

Check if a qeth device supports IPv6 TX checksum offload, and advertise
NETIF_F_IPV6_CSUM accordingly. Add support for setting the relevant bits
in IPv6 packet descriptors.

Currently this has only limited use (ie. UDP, or Jumbo Frames). For any
TCP traffic with a standard MSS, the TCP checksum gets calculated
as part of the linear GSO segmentation.

Signed-off-by: Kittipon Meesompop <kmeesomp@linux.vnet.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 38 insertions, 15 deletions

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 7cbc9bf5d6b0..2a5fec55bf60 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -878,14 +878,17 @@ static inline void qeth_rx_csum(struct qeth_card *card, struct sk_buff *skb,
         }
 }
 
-static inline void qeth_tx_csum(struct sk_buff *skb, u8 *flags)
+static inline void qeth_tx_csum(struct sk_buff *skb, u8 *flags, int ipv)
 {
         *flags |= QETH_HDR_EXT_CSUM_TRANSP_REQ;
-        if (ip_hdr(skb)->protocol == IPPROTO_UDP)
+        if ((ipv == 4 && ip_hdr(skb)->protocol == IPPROTO_UDP) ||
+            (ipv == 6 && ipv6_hdr(skb)->nexthdr == IPPROTO_UDP))
                 *flags |= QETH_HDR_EXT_UDP;
-        /* some HW requires combined L3+L4 csum offload: */
-        *flags |= QETH_HDR_EXT_CSUM_HDR_REQ;
-        ip_hdr(skb)->check = 0;
+        if (ipv == 4) {
+                /* some HW requires combined L3+L4 csum offload: */
+                *flags |= QETH_HDR_EXT_CSUM_HDR_REQ;
+                ip_hdr(skb)->check = 0;
+        }
 }
 
 static inline void qeth_put_buffer_pool_entry(struct qeth_card *card,
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 5e4a509822f1..55b05d9c1cb6 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -6349,12 +6349,12 @@ static int qeth_ipa_checksum_run_cmd(struct qeth_card *card,
 static int qeth_send_checksum_on(struct qeth_card *card, int cstype,
                                  enum qeth_prot_versions prot)
 {
-        const __u32 required_features = QETH_IPA_CHECKSUM_IP_HDR |
-                                        QETH_IPA_CHECKSUM_UDP |
-                                        QETH_IPA_CHECKSUM_TCP;
+        u32 required_features = QETH_IPA_CHECKSUM_UDP | QETH_IPA_CHECKSUM_TCP;
         struct qeth_checksum_cmd chksum_cb;
         int rc;
 
+        if (prot == QETH_PROT_IPV4)
+                required_features |= QETH_IPA_CHECKSUM_IP_HDR;
         rc = qeth_ipa_checksum_run_cmd(card, cstype, IPA_CMD_ASS_START, 0,
                                        &chksum_cb, prot);
         if (!rc) {
@@ -6430,8 +6430,8 @@ static int qeth_set_ipa_tso(struct qeth_card *card, int on)
         return rc;
 }
 
-#define QETH_HW_FEATURES (NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_TSO)
-
+#define QETH_HW_FEATURES (NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_TSO | \
+                          NETIF_F_IPV6_CSUM)
 /**
  * qeth_recover_features() - Restore device features after recovery
  * @dev:        the recovering net_device
@@ -6471,6 +6471,12 @@ int qeth_set_features(struct net_device *dev, netdev_features_t features)
                 if (rc)
                         changed ^= NETIF_F_IP_CSUM;
         }
+        if (changed & NETIF_F_IPV6_CSUM) {
+                rc = qeth_set_ipa_csum(card, features & NETIF_F_IPV6_CSUM,
+                                       IPA_OUTBOUND_CHECKSUM, QETH_PROT_IPV6);
+                if (rc)
+                        changed ^= NETIF_F_IPV6_CSUM;
+        }
         if ((changed & NETIF_F_RXCSUM)) {
                 rc = qeth_set_ipa_csum(card, features & NETIF_F_RXCSUM,
                                        IPA_INBOUND_CHECKSUM, QETH_PROT_IPV4);
@@ -6500,6 +6506,8 @@ netdev_features_t qeth_fix_features(struct net_device *dev,
         QETH_DBF_TEXT(SETUP, 2, "fixfeat");
         if (!qeth_is_supported(card, IPA_OUTBOUND_CHECKSUM))
                 features &= ~NETIF_F_IP_CSUM;
+        if (!qeth_is_supported6(card, IPA_OUTBOUND_CHECKSUM_V6))
+                features &= ~NETIF_F_IPV6_CSUM;
         if (!qeth_is_supported(card, IPA_INBOUND_CHECKSUM))
                 features &= ~NETIF_F_RXCSUM;
         if (!qeth_is_supported(card, IPA_OUTBOUND_TSO))
diff --git a/drivers/s390/net/qeth_core_mpc.h b/drivers/s390/net/qeth_core_mpc.h
index f4d1ec0b8f5a..af3c35fbfa9e 100644
--- a/drivers/s390/net/qeth_core_mpc.h
+++ b/drivers/s390/net/qeth_core_mpc.h
@@ -246,6 +246,7 @@ enum qeth_ipa_funcs {
         IPA_QUERY_ARP_ASSIST    = 0x00040000L,
         IPA_INBOUND_TSO         = 0x00080000L,
         IPA_OUTBOUND_TSO        = 0x00100000L,
+        IPA_OUTBOUND_CHECKSUM_V6 = 0x00800000L,
 };
 
 /* SETIP/DELIP IPA Command: ***************************************************/
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 945df56434fd..5b1780fa4cb5 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -660,7 +660,8 @@ out:
 }
 
 static int qeth_l2_xmit_osa(struct qeth_card *card, struct sk_buff *skb,
-                            struct qeth_qdio_out_q *queue, int cast_type)
+                            struct qeth_qdio_out_q *queue, int cast_type,
+                            int ipv)
 {
         int push_len = sizeof(struct qeth_hdr);
         unsigned int elements, nr_frags;
@@ -699,7 +700,7 @@ static int qeth_l2_xmit_osa(struct qeth_card *card, struct sk_buff *skb,
         }
         qeth_l2_fill_header(hdr, skb, cast_type, skb->len - push_len);
         if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                qeth_tx_csum(skb, &hdr->hdr.l2.flags[1]);
+                qeth_tx_csum(skb, &hdr->hdr.l2.flags[1], ipv);
                 if (card->options.performance_stats)
                         card->perf_stats.tx_csum++;
         }
@@ -754,6 +755,7 @@ static netdev_tx_t qeth_l2_hard_start_xmit(struct sk_buff *skb,
 {
         struct qeth_card *card = dev->ml_priv;
         int cast_type = qeth_l2_get_cast_type(card, skb);
+        int ipv = qeth_get_ip_version(skb);
         struct qeth_qdio_out_q *queue;
         int tx_bytes = skb->len;
         int rc;
@@ -761,7 +763,7 @@ static netdev_tx_t qeth_l2_hard_start_xmit(struct sk_buff *skb,
         if (card->qdio.do_prio_queueing || (cast_type &&
                                         card->info.is_multicast_different))
                 queue = card->qdio.out_qs[qeth_get_priority_queue(card, skb,
-                                        qeth_get_ip_version(skb), cast_type)];
+                                        ipv, cast_type)];
         else
                 queue = card->qdio.out_qs[card->qdio.default_out_queue];
 
@@ -784,7 +786,7 @@ static netdev_tx_t qeth_l2_hard_start_xmit(struct sk_buff *skb,
                 rc = qeth_l2_xmit_iqd(card, skb, queue, cast_type);
                 break;
         default:
-                rc = qeth_l2_xmit_osa(card, skb, queue, cast_type);
+                rc = qeth_l2_xmit_osa(card, skb, queue, cast_type, ipv);
         }
 
         if (!rc) {
@@ -995,6 +997,10 @@ static int qeth_l2_setup_netdev(struct qeth_card *card)
                         card->dev->vlan_features |= NETIF_F_RXCSUM;
                 }
         }
+        if (qeth_is_supported6(card, IPA_OUTBOUND_CHECKSUM_V6)) {
+                card->dev->hw_features |= NETIF_F_IPV6_CSUM;
+                card->dev->vlan_features |= NETIF_F_IPV6_CSUM;
+        }
 
         card->info.broadcast_capable = 1;
         qeth_l2_request_initial_mac(card);
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index dd233fe3d6c4..e7fa479adf47 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2281,7 +2281,7 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
                 }
 
                 if (new_skb->ip_summed == CHECKSUM_PARTIAL) {
-                        qeth_tx_csum(new_skb, &hdr->hdr.l3.ext_flags);
+                        qeth_tx_csum(new_skb, &hdr->hdr.l3.ext_flags, ipv);
                         if (card->options.performance_stats)
                                 card->perf_stats.tx_csum++;
                 }
@@ -2507,6 +2507,11 @@ static int qeth_l3_setup_netdev(struct qeth_card *card)
                         card->dev->vlan_features |= NETIF_F_TSO |
                                 NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
                 }
+
+                if (qeth_is_supported6(card, IPA_OUTBOUND_CHECKSUM_V6)) {
+                        card->dev->hw_features |= NETIF_F_IPV6_CSUM;
+                        card->dev->vlan_features |= NETIF_F_IPV6_CSUM;
+                }
         } else if (card->info.type == QETH_CARD_TYPE_IQD) {
                 card->dev = alloc_netdev(0, "hsi%d", NET_NAME_UNKNOWN,
                                          ether_setup);