[dpdk-dev] [PATCH 3/3] pmd i40e: Enable Transmit Segmentation Offload for TCP traffic

[miroslaw.walukiewicz@intel.com]

From: Miroslaw Walukiewicz <miroslaw.walukiewicz@intel.com>

The patch enables the TSO HW feature for i40e PMD driver.

The feature is reported by rte_dev_info_get() if enabled.

Signed-off-by: Mirek Walukiewicz <miroslaw.walukiewicz@intel.com>
---
 lib/librte_pmd_i40e/i40e_ethdev.c |    1 +
 lib/librte_pmd_i40e/i40e_rxtx.c   |   56 ++++++++++++++++++++++++++++++++++---
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/lib/librte_pmd_i40e/i40e_ethdev.c b/lib/librte_pmd_i40e/i40e_ethdev.c
index 46c43a7..01b21eb 100644
--- a/lib/librte_pmd_i40e/i40e_ethdev.c
+++ b/lib/librte_pmd_i40e/i40e_ethdev.c
@@ -1399,6 +1399,7 @@ i40e_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 		DEV_TX_OFFLOAD_IPV4_CKSUM |
 		DEV_TX_OFFLOAD_UDP_CKSUM |
 		DEV_TX_OFFLOAD_TCP_CKSUM |
+		DEV_TX_OFFLOAD_TCP_TSO |
 		DEV_TX_OFFLOAD_SCTP_CKSUM;
 
 	dev_info->default_rxconf = (struct rte_eth_rxconf) {
diff --git a/lib/librte_pmd_i40e/i40e_rxtx.c b/lib/librte_pmd_i40e/i40e_rxtx.c
index 2b53677..bc7af2b 100644
--- a/lib/librte_pmd_i40e/i40e_rxtx.c
+++ b/lib/librte_pmd_i40e/i40e_rxtx.c
@@ -50,6 +50,8 @@
 #include <rte_tcp.h>
 #include <rte_sctp.h>
 #include <rte_udp.h>
+#include <rte_ip.h>
+#include <rte_tcp_off.h>
 
 #include "i40e_logs.h"
 #include "i40e/i40e_prototype.h"
@@ -440,6 +442,11 @@ i40e_txd_enable_checksum(uint32_t ol_flags,
 		*td_offset |= (l3_len >> 2) << I40E_TX_DESC_LENGTH_IPLEN_SHIFT;
 	}
 
+	if (ol_flags & PKT_TX_TCP_TSO) {
+		*td_cmd |= I40E_TX_DESC_CMD_L4T_EOFT_TCP;
+		/* td offset will be set next */
+		return;
+	}
 	/* Enable L4 checksum offloads */
 	switch (ol_flags & PKT_TX_L4_MASK) {
 	case PKT_TX_TCP_CKSUM:
@@ -1073,12 +1080,46 @@ i40e_calc_context_desc(uint64_t flags)
 #ifdef RTE_LIBRTE_IEEE1588
 	mask |= PKT_TX_IEEE1588_TMST;
 #endif
+	/* need for context descriptor when TSO enabled */
+	mask |= PKT_TX_TCP_TSO;
 	if (flags & mask)
 		return 1;
 
 	return 0;
 }
 
+/* set i40e TSO context descriptor */
+static inline uint64_t 
+i40e_set_tso_ctx(struct rte_mbuf *mbuf, uint8_t l2_len, uint8_t l3_len, uint32_t *td_offset)
+{
+	uint64_t ctx_desc;
+	struct ipv4_hdr *ip;
+	struct tcp_hdr *th;
+	uint32_t tcp_hlen;
+	uint32_t hdrlen;
+	uint32_t paylen;
+	
+	/* set mss */
+	ip = (struct ipv4_hdr *) (rte_pktmbuf_mtod(mbuf, unsigned char *) + l2_len);
+	ip->hdr_checksum = 0;
+	ip->total_length = 0;
+	th = (struct tcp_hdr *)((caddr_t)ip + l3_len);
+	th->cksum = rte_in_pseudo(ip->src_addr, ip->dst_addr, I40E_HTONS(IPPROTO_TCP));
+	tcp_hlen = (th->data_off >> 4) << 2;
+	*td_offset |= (tcp_hlen >> 2) <<
+				I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
+	hdrlen = l2_len + l3_len + tcp_hlen;
+	paylen = mbuf->pkt_len - hdrlen;
+
+	ctx_desc = ((uint64_t)mbuf->tso_segsz << 
+						I40E_TXD_CTX_QW1_MSS_SHIFT) |
+		    ((uint64_t)paylen << I40E_TXD_CTX_QW1_TSO_LEN_SHIFT) |
+		    ((uint64_t)I40E_TX_CTX_DESC_TSO <<
+						I40E_TXD_CTX_QW1_CMD_SHIFT);
+
+	return ctx_desc;
+}
+
 uint16_t
 i40e_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
@@ -1192,12 +1233,19 @@ i40e_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 				rte_pktmbuf_free_seg(txe->mbuf);
 				txe->mbuf = NULL;
 			}
+			/* TSO enabled means no timestamp */
+			if (ol_flags & PKT_TX_TCP_TSO) {
+				cd_type_cmd_tso_mss |= 
+					i40e_set_tso_ctx(tx_pkt, l2_len, l3_len, &td_offset);
+			}
+			else {	
 #ifdef RTE_LIBRTE_IEEE1588
-			if (ol_flags & PKT_TX_IEEE1588_TMST)
-				cd_type_cmd_tso_mss |=
-					((uint64_t)I40E_TX_CTX_DESC_TSYN <<
-						I40E_TXD_CTX_QW1_CMD_SHIFT);
+				if (ol_flags & PKT_TX_IEEE1588_TMST)
+					cd_type_cmd_tso_mss |=
+						((uint64_t)I40E_TX_CTX_DESC_TSYN <<
+							I40E_TXD_CTX_QW1_CMD_SHIFT);
 #endif
+			}
 			ctx_txd->tunneling_params =
 				rte_cpu_to_le_32(cd_tunneling_params);
 			ctx_txd->l2tag2 = rte_cpu_to_le_16(cd_l2tag2);