alx: add tso support

Add tso/tso6 support to the alx driver.
Based on information from the downstream driver at github.com/qca/alx

Signed-off-by: Tobias Regnery <tobias.regnery@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c
index 6453148..c4d0026 100644 (file)
--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/drivers/net/ethernet/atheros/alx/main.c
@@ -993,6 +993,18 @@ static void alx_reset(struct work_struct *work)
        rtnl_unlock();
 }
 
+static int alx_tpd_req(struct sk_buff *skb)
+{
+       int num;
+
+       num = skb_shinfo(skb)->nr_frags + 1;
+       /* we need one extra descriptor for LSOv2 */
+       if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
+               num++;
+
+       return num;
+}
+
 static int alx_tx_csum(struct sk_buff *skb, struct alx_txd *first)
 {
        u8 cso, css;
@@ -1012,6 +1024,45 @@ static int alx_tx_csum(struct sk_buff *skb, struct alx_txd *first)
        return 0;
 }
 
+static int alx_tso(struct sk_buff *skb, struct alx_txd *first)
+{
+       int err;
+
+       if (skb->ip_summed != CHECKSUM_PARTIAL)
+               return 0;
+
+       if (!skb_is_gso(skb))
+               return 0;
+
+       err = skb_cow_head(skb, 0);
+       if (err < 0)
+               return err;
+
+       if (skb->protocol == htons(ETH_P_IP)) {
+               struct iphdr *iph = ip_hdr(skb);
+
+               iph->check = 0;
+               tcp_hdr(skb)->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
+                                                        0, IPPROTO_TCP, 0);
+               first->word1 |= 1 << TPD_IPV4_SHIFT;
+       } else if (skb_is_gso_v6(skb)) {
+               ipv6_hdr(skb)->payload_len = 0;
+               tcp_hdr(skb)->check = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+                                                      &ipv6_hdr(skb)->daddr,
+                                                      0, IPPROTO_TCP, 0);
+               /* LSOv2: the first TPD only provides the packet length */
+               first->adrl.l.pkt_len = skb->len;
+               first->word1 |= 1 << TPD_LSO_V2_SHIFT;
+       }
+
+       first->word1 |= 1 << TPD_LSO_EN_SHIFT;
+       first->word1 |= (skb_transport_offset(skb) &
+                        TPD_L4HDROFFSET_MASK) << TPD_L4HDROFFSET_SHIFT;
+       first->word1 |= (skb_shinfo(skb)->gso_size &
+                        TPD_MSS_MASK) << TPD_MSS_SHIFT;
+       return 1;
+}
+
 static int alx_map_tx_skb(struct alx_priv *alx, struct sk_buff *skb)
 {
        struct alx_tx_queue *txq = &alx->txq;
@@ -1022,6 +1073,16 @@ static int alx_map_tx_skb(struct alx_priv *alx, struct sk_buff *skb)
        first_tpd = &txq->tpd[txq->write_idx];
        tpd = first_tpd;
 
+       if (tpd->word1 & (1 << TPD_LSO_V2_SHIFT)) {
+               if (++txq->write_idx == alx->tx_ringsz)
+                       txq->write_idx = 0;
+
+               tpd = &txq->tpd[txq->write_idx];
+               tpd->len = first_tpd->len;
+               tpd->vlan_tag = first_tpd->vlan_tag;
+               tpd->word1 = first_tpd->word1;
+       }
+
        maplen = skb_headlen(skb);
        dma = dma_map_single(&alx->hw.pdev->dev, skb->data, maplen,
                             DMA_TO_DEVICE);
@@ -1082,9 +1143,9 @@ static netdev_tx_t alx_start_xmit(struct sk_buff *skb,
        struct alx_priv *alx = netdev_priv(netdev);
        struct alx_tx_queue *txq = &alx->txq;
        struct alx_txd *first;
-       int tpdreq = skb_shinfo(skb)->nr_frags + 1;
+       int tso;
 
-       if (alx_tpd_avail(alx) < tpdreq) {
+       if (alx_tpd_avail(alx) < alx_tpd_req(skb)) {
                netif_stop_queue(alx->dev);
                goto drop;
        }
@@ -1092,7 +1153,10 @@ static netdev_tx_t alx_start_xmit(struct sk_buff *skb,
        first = &txq->tpd[txq->write_idx];
        memset(first, 0, sizeof(*first));
 
-       if (alx_tx_csum(skb, first))
+       tso = alx_tso(skb, first);
+       if (tso < 0)
+               goto drop;
+       else if (!tso && alx_tx_csum(skb, first))
                goto drop;
 
        if (alx_map_tx_skb(alx, skb) < 0)
@@ -1351,7 +1415,10 @@ static int alx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
                }
        }
 
-       netdev->hw_features = NETIF_F_SG | NETIF_F_HW_CSUM;
+       netdev->hw_features = NETIF_F_SG |
+                             NETIF_F_HW_CSUM |
+                             NETIF_F_TSO |
+                             NETIF_F_TSO6;
 
        if (alx_get_perm_macaddr(hw, hw->perm_addr)) {
                dev_warn(&pdev->dev,