[RFC PATCH 07/27] net/ice: refactor context descriptor handling

[Bruce Richardson]

Create a single function to manage all context descriptor handling,
which returns either 0 or 1 depending on whether a descriptor is needed
or not, as well as returning directly the descriptor contents if
relevant.

Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
---
 drivers/net/intel/ice/ice_rxtx.c | 96 ++++++++++++++++++--------------
 1 file changed, 55 insertions(+), 41 deletions(-)

diff --git a/drivers/net/intel/ice/ice_rxtx.c b/drivers/net/intel/ice/ice_rxtx.c
index c2a38b1a13..b90a1b4ec4 100644
--- a/drivers/net/intel/ice/ice_rxtx.c
+++ b/drivers/net/intel/ice/ice_rxtx.c
@@ -3044,7 +3044,7 @@ ice_calc_context_desc(uint64_t flags)
 
 /* set ice TSO context descriptor */
 static inline uint64_t
-ice_set_tso_ctx(struct rte_mbuf *mbuf, union ci_tx_offload tx_offload)
+ice_set_tso_ctx(uint64_t ol_flags, const struct rte_mbuf *mbuf, union ci_tx_offload tx_offload)
 {
 	uint64_t ctx_desc = 0;
 	uint32_t cd_cmd, hdr_len, cd_tso_len;
@@ -3055,7 +3055,7 @@ ice_set_tso_ctx(struct rte_mbuf *mbuf, union ci_tx_offload tx_offload)
 	}
 
 	hdr_len = tx_offload.l2_len + tx_offload.l3_len + tx_offload.l4_len;
-	hdr_len += (mbuf->ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) ?
+	hdr_len += (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) ?
 		   tx_offload.outer_l2_len + tx_offload.outer_l3_len : 0;
 
 	cd_cmd = CI_TX_CTX_DESC_TSO;
@@ -3067,6 +3067,51 @@ ice_set_tso_ctx(struct rte_mbuf *mbuf, union ci_tx_offload tx_offload)
 	return ctx_desc;
 }
 
+/* compute a context descriptor if one is necessary based on the ol_flags
+ *
+ * Returns 0 if no descriptor is necessary.
+ * Returns 1 if one is necessary and the contents of the descriptor are returned
+ *   in the values pointed to by qw0 and qw1. td_offset may also be modified.
+ */
+static __rte_always_inline uint16_t
+get_context_desc(uint64_t ol_flags, const struct rte_mbuf *tx_pkt,
+	const union ci_tx_offload *tx_offload, const struct ci_tx_queue *txq,
+	uint32_t *td_offset, uint64_t *qw0, uint64_t *qw1)
+{
+	uint16_t cd_l2tag2 = 0;
+	uint64_t cd_type_cmd_tso_mss = ICE_TX_DESC_DTYPE_CTX;
+	uint32_t cd_tunneling_params = 0;
+	uint64_t ptp_tx_index = txq->ice_vsi->adapter->ptp_tx_index;
+
+	if (ice_calc_context_desc(ol_flags) == 0)
+		return 0;
+
+	if (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) {
+		*td_offset |= (tx_offload->outer_l2_len >> 1) << CI_TX_DESC_LEN_MACLEN_S;
+		ice_parse_tunneling_params(ol_flags, *tx_offload, &cd_tunneling_params);
+	}
+
+	if (ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG))
+		cd_type_cmd_tso_mss |= ice_set_tso_ctx(ol_flags, tx_pkt, *tx_offload);
+	else if (ol_flags & RTE_MBUF_F_TX_IEEE1588_TMST)
+		cd_type_cmd_tso_mss |=
+			((uint64_t)CI_TX_CTX_DESC_TSYN << CI_TXD_QW1_CMD_S) |
+			((ptp_tx_index << ICE_TXD_CTX_QW1_TSYN_S) & ICE_TXD_CTX_QW1_TSYN_M);
+
+
+	/* TX context descriptor based double VLAN insert */
+	if (ol_flags & RTE_MBUF_F_TX_QINQ) {
+		cd_l2tag2 = tx_pkt->vlan_tci_outer;
+		cd_type_cmd_tso_mss |= ((uint64_t)CI_TX_CTX_DESC_IL2TAG2 << CI_TXD_QW1_CMD_S);
+	}
+
+	*qw0 = rte_cpu_to_le_32(cd_tunneling_params) |
+		((uint64_t)rte_cpu_to_le_16(cd_l2tag2) << 32);
+	*qw1 = rte_cpu_to_le_64(cd_type_cmd_tso_mss);
+
+	return 1;
+}
+
 uint16_t
 ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
@@ -3077,7 +3122,6 @@ ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 	struct ci_tx_entry *txe, *txn;
 	struct rte_mbuf *tx_pkt;
 	struct rte_mbuf *m_seg;
-	uint32_t cd_tunneling_params;
 	uint16_t tx_id;
 	uint16_t ts_id = -1;
 	uint16_t nb_tx;
@@ -3106,20 +3150,24 @@ ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		(void)ci_tx_xmit_cleanup(txq);
 
 	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
+		uint64_t cd_qw0, cd_qw1;
 		tx_pkt = *tx_pkts++;
 
 		td_cmd = 0;
 		td_tag = 0;
 		td_offset = 0;
 		ol_flags = tx_pkt->ol_flags;
+
 		tx_offload.l2_len = tx_pkt->l2_len;
 		tx_offload.l3_len = tx_pkt->l3_len;
 		tx_offload.outer_l2_len = tx_pkt->outer_l2_len;
 		tx_offload.outer_l3_len = tx_pkt->outer_l3_len;
 		tx_offload.l4_len = tx_pkt->l4_len;
 		tx_offload.tso_segsz = tx_pkt->tso_segsz;
+
 		/* Calculate the number of context descriptors needed. */
-		nb_ctx = ice_calc_context_desc(ol_flags);
+		nb_ctx = get_context_desc(ol_flags, tx_pkt, &tx_offload,
+			txq, &td_offset, &cd_qw0, &cd_qw1);
 
 		/* The number of descriptors that must be allocated for
 		 * a packet equals to the number of the segments of that
@@ -3161,15 +3209,6 @@ ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 			td_tag = tx_pkt->vlan_tci;
 		}
 
-		/* Fill in tunneling parameters if necessary */
-		cd_tunneling_params = 0;
-		if (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) {
-			td_offset |= (tx_offload.outer_l2_len >> 1)
-				<< CI_TX_DESC_LEN_MACLEN_S;
-			ice_parse_tunneling_params(ol_flags, tx_offload,
-						   &cd_tunneling_params);
-		}
-
 		/* Enable checksum offloading */
 		if (ol_flags & ICE_TX_CKSUM_OFFLOAD_MASK)
 			ice_txd_enable_checksum(ol_flags, &td_cmd,
@@ -3177,11 +3216,7 @@ ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 
 		if (nb_ctx) {
 			/* Setup TX context descriptor if required */
-			volatile struct ice_tx_ctx_desc *ctx_txd =
-				(volatile struct ice_tx_ctx_desc *)
-					&ci_tx_ring[tx_id];
-			uint16_t cd_l2tag2 = 0;
-			uint64_t cd_type_cmd_tso_mss = ICE_TX_DESC_DTYPE_CTX;
+			uint64_t *ctx_txd = RTE_CAST_PTR(uint64_t *, &ci_tx_ring[tx_id]);
 
 			txn = &sw_ring[txe->next_id];
 			RTE_MBUF_PREFETCH_TO_FREE(txn->mbuf);
@@ -3190,29 +3225,8 @@ ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 				txe->mbuf = NULL;
 			}
 
-			if (ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG))
-				cd_type_cmd_tso_mss |=
-					ice_set_tso_ctx(tx_pkt, tx_offload);
-			else if (ol_flags & RTE_MBUF_F_TX_IEEE1588_TMST)
-				cd_type_cmd_tso_mss |=
-					((uint64_t)CI_TX_CTX_DESC_TSYN <<
-					CI_TXD_QW1_CMD_S) |
-					 (((uint64_t)txq->ice_vsi->adapter->ptp_tx_index <<
-					 ICE_TXD_CTX_QW1_TSYN_S) & ICE_TXD_CTX_QW1_TSYN_M);
-
-			ctx_txd->tunneling_params =
-				rte_cpu_to_le_32(cd_tunneling_params);
-
-			/* TX context descriptor based double VLAN insert */
-			if (ol_flags & RTE_MBUF_F_TX_QINQ) {
-				cd_l2tag2 = tx_pkt->vlan_tci_outer;
-				cd_type_cmd_tso_mss |=
-					((uint64_t)CI_TX_CTX_DESC_IL2TAG2 <<
-					 CI_TXD_QW1_CMD_S);
-			}
-			ctx_txd->l2tag2 = rte_cpu_to_le_16(cd_l2tag2);
-			ctx_txd->qw1 =
-				rte_cpu_to_le_64(cd_type_cmd_tso_mss);
+			ctx_txd[0] = cd_qw0;
+			ctx_txd[1] = cd_qw1;
 
 			txe->last_id = tx_last;
 			tx_id = txe->next_id;
-- 
2.51.0