net/sfc: support VLAN offload on transmit path

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Andrew Lee <alee@solarflare.com>
Reviewed-by: Robert Stonehouse <rstonehouse@solarflare.com>

doc/guides/nics/features/sfc_efx.ini

@@ -15,6 +15,7 @@ Promiscuous mode     = Y
 Allmulticast mode    = Y
 Multicast MAC filter = Y
 Flow control         = Y
+VLAN offload         = P
 L3 checksum offload  = Y
 L4 checksum offload  = Y
 Packet type parsing  = Y

doc/guides/nics/sfc_efx.rst

@@ -73,6 +73,8 @@ SFC EFX PMD has support for:
 
 - Deferred receive and transmit queue start
 
+- Transmit VLAN insertion (if running firmware variant supports it)
+
 
 Non-supported Features
 ----------------------

drivers/net/sfc/sfc_ethdev.c

@@ -46,6 +46,7 @@ static void
 sfc_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 {
 	struct sfc_adapter *sa = dev->data->dev_private;
+	const efx_nic_cfg_t *encp = efx_nic_cfg_get(sa->nic);
 
 	sfc_log_init(sa, "entry");
 
@@ -77,8 +78,11 @@ sfc_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 		DEV_TX_OFFLOAD_UDP_CKSUM |
 		DEV_TX_OFFLOAD_TCP_CKSUM;
 
-	dev_info->default_txconf.txq_flags = ETH_TXQ_FLAGS_NOVLANOFFL |
-					     ETH_TXQ_FLAGS_NOXSUMSCTP;
+	dev_info->default_txconf.txq_flags = ETH_TXQ_FLAGS_NOXSUMSCTP;
+	if (!encp->enc_hw_tx_insert_vlan_enabled)
+		dev_info->default_txconf.txq_flags |= ETH_TXQ_FLAGS_NOVLANOFFL;
+	else
+		dev_info->tx_offload_capa |= DEV_TX_OFFLOAD_VLAN_INSERT;
 
 	dev_info->rx_desc_lim.nb_max = EFX_RXQ_MAXNDESCS;
 	dev_info->rx_desc_lim.nb_min = EFX_RXQ_MINNDESCS;

drivers/net/sfc/sfc_tx.c

@@ -58,6 +58,7 @@ sfc_tx_qcheck_conf(struct sfc_adapter *sa, uint16_t nb_tx_desc,
 		   const struct rte_eth_txconf *tx_conf)
 {
 	unsigned int flags = tx_conf->txq_flags;
+	const efx_nic_cfg_t *encp = efx_nic_cfg_get(sa->nic);
 	int rc = 0;
 
 	if (tx_conf->tx_rs_thresh != 0) {
@@ -80,7 +81,8 @@ sfc_tx_qcheck_conf(struct sfc_adapter *sa, uint16_t nb_tx_desc,
 		rc = EINVAL;
 	}
 
-	if ((flags & ETH_TXQ_FLAGS_NOVLANOFFL) == 0) {
+	if (!encp->enc_hw_tx_insert_vlan_enabled &&
+	    (flags & ETH_TXQ_FLAGS_NOVLANOFFL) == 0) {
 		sfc_err(sa, "VLAN offload is not supported");
 		rc = EINVAL;
 	}
@@ -384,6 +386,7 @@ sfc_tx_qstart(struct sfc_adapter *sa, unsigned int sw_index)
 		goto fail_tx_qcreate;
 
 	txq->added = txq->pending = txq->completed = desc_index;
+	txq->hw_vlan_tci = 0;
 
 	efx_tx_qenable(txq->common);
 
@@ -533,6 +536,37 @@ sfc_tx_stop(struct sfc_adapter *sa)
 	efx_tx_fini(sa->nic);
 }
 
+/*
+ * The function is used to insert or update VLAN tag;
+ * the firmware has state of the firmware tag to insert per TxQ
+ * (controlled by option descriptors), hence, if the tag of the
+ * packet to be sent is different from one remembered by the firmware,
+ * the function will update it
+ */
+static unsigned int
+sfc_tx_maybe_insert_tag(struct sfc_txq *txq, struct rte_mbuf *m,
+			efx_desc_t **pend)
+{
+	uint16_t this_tag = ((m->ol_flags & PKT_TX_VLAN_PKT) ?
+			     m->vlan_tci : 0);
+
+	if (this_tag == txq->hw_vlan_tci)
+		return 0;
+
+	/*
+	 * The expression inside SFC_ASSERT() is not desired to be checked in
+	 * a non-debug build because it might be too expensive on the data path
+	 */
+	SFC_ASSERT(efx_nic_cfg_get(txq->evq->sa->nic)->enc_hw_tx_insert_vlan_enabled);
+
+	efx_tx_qdesc_vlantci_create(txq->common, rte_cpu_to_be_16(this_tag),
+				    *pend);
+	(*pend)++;
+	txq->hw_vlan_tci = this_tag;
+
+	return 1;
+}
+
 uint16_t
 sfc_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
@@ -574,6 +608,15 @@ sfc_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		size_t			pkt_len = m_seg->pkt_len;
 		unsigned int		pkt_descs = 0;
 
+		/*
+		 * Here VLAN TCI is expected to be zero in case if no
+		 * DEV_TX_VLAN_OFFLOAD capability is advertised;
+		 * if the calling app ignores the absence of
+		 * DEV_TX_VLAN_OFFLOAD and pushes VLAN TCI, then
+		 * TX_ERROR will occur
+		 */
+		pkt_descs += sfc_tx_maybe_insert_tag(txq, m_seg, &pend);
+
 		for (; m_seg != NULL; m_seg = m_seg->next) {
 			efsys_dma_addr_t	next_frag;
 			size_t			seg_len;

drivers/net/sfc/sfc_tx.h

@@ -77,6 +77,7 @@ struct sfc_txq {
 	unsigned int		pending;
 	unsigned int		completed;
 	unsigned int		free_thresh;
+	uint16_t		hw_vlan_tci;
 
 	unsigned int		hw_index;
 	unsigned int		flags;