r8152: support TSO

Support scatter gather and TSO.

Adjust the tx checksum function and set the max gso size to fix the
size of the tx aggregation buffer.

Change-Id: Iff3dde25a2329fb47de6a5b6bfce92f260276992
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Aly Hirani <ahirani@nvidia.com>
Reviewed-on: http://git-master/r/390297
(cherry picked from commit 5af199861e22e25c0454676b992298ddfe4d6111)
Reviewed-on: http://git-master/r/396899
Reviewed-by: Preetham Chandru <pchandru@nvidia.com>
Tested-by: Preetham Chandru <pchandru@nvidia.com>
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>

1 files changed, 87 insertions, 30 deletions

diff --git a/drivers/net/usb/r8152_shield.c b/drivers/net/usb/r8152_shield.c
index 571a2af3c..6d86f5943 100644
--- a/drivers/net/usb/r8152_shield.c
+++ b/drivers/net/usb/r8152_shield.c
@@ -24,7 +24,7 @@
 #include <linux/ipv6.h>
 
 /* Version Information */
-#define DRIVER_VERSION "v1.05.0 (2014/02/18)"
+#define DRIVER_VERSION "v1.06.0 (2014/03/03)"
 #define DRIVER_AUTHOR "Realtek linux nic maintainers <nic_swsd@realtek.com>"
 #define DRIVER_DESC "Realtek RTL8152/RTL8153 Based USB Ethernet Adapters"
 #define MODULENAME "r8152"
@@ -485,13 +485,18 @@ struct tx_desc {
         __le32 opts1;
 #define TX_FS                   (1 << 31) /* First segment of a packet */
 #define TX_LS                   (1 << 30) /* Final segment of a packet */
-#define TX_LEN_MASK             0x3ffff
+#define GTSENDV4                (1 << 28)
+#define GTTCPHO_SHIFT           18
+#define TX_LEN_MAX              0x3ffffU
 
         __le32 opts2;
 #define UDP_CS                  (1 << 31) /* Calculate UDP/IP checksum */
 #define TCP_CS                  (1 << 30) /* Calculate TCP/IP checksum */
 #define IPV4_CS                 (1 << 29) /* Calculate IPv4 checksum */
 #define IPV6_CS                 (1 << 28) /* Calculate IPv6 checksum */
+#define MSS_SHIFT               17
+#define MSS_MAX                 0x7ffU
+#define TCPHO_SHIFT             17
 };
 
 struct r8152;
@@ -558,12 +563,21 @@ enum rtl_version {
         RTL_VER_MAX
 };
 
+enum tx_csum_stat {
+        TX_CSUM_SUCCESS = 0,
+        TX_CSUM_TSO,
+        TX_CSUM_NONE
+};
+
 /* Maximum number of multicast addresses to filter (vs. Rx-all-multicast).
  * The RTL chips use a 64 element hash table based on the Ethernet CRC.
  */
 static const int multicast_filter_limit = 32;
 static unsigned int rx_buf_sz = 16384;
 
+#define RTL_LIMITED_TSO_SIZE    (rx_buf_sz - sizeof(struct tx_desc) - \
+                                 VLAN_ETH_HLEN - VLAN_HLEN)
+
 static
 int get_registers(struct r8152 *tp, u16 value, u16 index, u16 size, void *data)
 {
@@ -1290,24 +1304,46 @@ static struct tx_agg *r8152_get_tx_agg(struct r8152 *tp)
         return agg;
 }
 
-static void
-r8152_tx_csum(struct r8152 *tp, struct tx_desc *desc, struct sk_buff *skb)
+static inline __be16 get_protocol(struct sk_buff *skb)
 {
-        memset(desc, 0, sizeof(*desc));
+        __be16 protocol;
 
-        desc->opts1 = cpu_to_le32((skb->len & TX_LEN_MASK) | TX_FS | TX_LS);
+        if (skb->protocol == htons(ETH_P_8021Q))
+                protocol = vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
+        else
+                protocol = skb->protocol;
 
-        if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                __be16 protocol;
-                u8 ip_protocol;
-                u32 opts2 = 0;
+        return protocol;
+}
 
-                if (skb->protocol == htons(ETH_P_8021Q))
-                        protocol = vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
-                else
-                        protocol = skb->protocol;
+static int r8152_tx_csum(struct r8152 *tp, struct tx_desc *desc,
+                         struct sk_buff *skb, u32 len, u32 transport_offset)
+{
+        u32 mss = skb_shinfo(skb)->gso_size;
+        u32 opts1, opts2 = 0;
+        int ret = TX_CSUM_SUCCESS;
+
+        WARN_ON_ONCE(len > TX_LEN_MAX);
+
+        opts1 = len | TX_FS | TX_LS;
+
+        if (mss) {
+                switch (get_protocol(skb)) {
+                case htons(ETH_P_IP):
+                        opts1 |= GTSENDV4;
+                        break;
+
+                default:
+                        WARN_ON_ONCE(1);
+                        break;
+                }
+
+                opts1 |= transport_offset << GTTCPHO_SHIFT;
+                opts2 |= min(mss, MSS_MAX) << MSS_SHIFT;
+        } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
+                u8 ip_protocol;
 
-                switch (protocol) {
+                switch (get_protocol(skb)) {
                 case htons(ETH_P_IP):
                         opts2 |= IPV4_CS;
                         ip_protocol = ip_hdr(skb)->protocol;
@@ -1323,17 +1359,20 @@ r8152_tx_csum(struct r8152 *tp, struct tx_desc *desc, struct sk_buff *skb)
                         break;
                 }
 
-                if (ip_protocol == IPPROTO_TCP) {
+                if (ip_protocol == IPPROTO_TCP)
                         opts2 |= TCP_CS;
-                        opts2 |= (skb_transport_offset(skb) & 0x7fff) << 17;
-                } else if (ip_protocol == IPPROTO_UDP) {
+                else if (ip_protocol == IPPROTO_UDP)
                         opts2 |= UDP_CS;
-                } else {
+                else
                         WARN_ON_ONCE(1);
-                }
 
-                desc->opts2 = cpu_to_le32(opts2);
+                opts2 |= transport_offset << TCPHO_SHIFT;
         }
+
+        desc->opts2 = cpu_to_le32(opts2);
+        desc->opts1 = cpu_to_le32(opts1);
+
+        return ret;
 }
 
 static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
@@ -1355,29 +1394,44 @@ static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
                 struct tx_desc *tx_desc;
                 struct sk_buff *skb;
                 unsigned int len;
+                u32 offset;
 
                 skb = __skb_dequeue(&skb_head);
                 if (!skb)
                         break;
 
-                remain -= sizeof(*tx_desc);
-                len = skb->len;
-                if (remain < len) {
+                len = skb->len + sizeof(*tx_desc);
+
+                if (len > remain) {
                         __skb_queue_head(&skb_head, skb);
                         break;
                 }
 
                 tx_data = tx_agg_align(tx_data);
                 tx_desc = (struct tx_desc *)tx_data;
+
+                offset = (u32)skb_transport_offset(skb);
+
+                r8152_tx_csum(tp, tx_desc, skb, skb->len, offset);
+
                 tx_data += sizeof(*tx_desc);
 
-                r8152_tx_csum(tp, tx_desc, skb);
-                memcpy(tx_data, skb->data, len);
-                agg->skb_num++;
+                len = skb->len;
+                if (skb_copy_bits(skb, 0, tx_data, len) < 0) {
+                        struct net_device_stats *stats = &tp->netdev->stats;
+
+                        stats->tx_dropped++;
+                        dev_kfree_skb_any(skb);
+                        tx_data -= sizeof(*tx_desc);
+                        continue;
+                }
+
+                tx_data += len;
                 agg->skb_len += len;
+                agg->skb_num++;
+
                 dev_kfree_skb_any(skb);
 
-                tx_data += len;
                 remain = rx_buf_sz - (int)(tx_agg_align(tx_data) - agg->head);
         }
 
@@ -3143,10 +3197,13 @@ static int rtl8152_probe(struct usb_interface *intf,
         netdev->netdev_ops = &rtl8152_netdev_ops;
         netdev->watchdog_timeo = RTL8152_TX_TIMEOUT;
 
-        netdev->features |= NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
-        netdev->hw_features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
+        netdev->features |= NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_SG |
+                            NETIF_F_TSO | NETIF_F_FRAGLIST;
+        netdev->hw_features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_SG |
+                              NETIF_F_TSO | NETIF_F_FRAGLIST;
 
         SET_ETHTOOL_OPS(netdev, &ops);
+        netif_set_gso_max_size(netdev, RTL_LIMITED_TSO_SIZE);
 
         tp->mii.dev = netdev;
         tp->mii.mdio_read = read_mii_word;