[dpdk-dev] [PATCH 2/2] net/sfc: add support for Tx descriptor status API

[Andrew Rybchenko <arybchenko@solarflare.com>]

From: Ivan Malov <ivan.malov@oktetlabs.ru>

Support for the feature is added to EFX Tx datapath

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 doc/guides/nics/features/sfc_efx.ini |  1 +
 drivers/net/sfc/sfc_dp_tx.h          |  7 +++++++
 drivers/net/sfc/sfc_ef10_tx.c        | 10 +++++++++
 drivers/net/sfc/sfc_ethdev.c         | 10 +++++++++
 drivers/net/sfc/sfc_tx.c             | 39 ++++++++++++++++++++++++++++++++++++
 5 files changed, 67 insertions(+)

diff --git a/doc/guides/nics/features/sfc_efx.ini b/doc/guides/nics/features/sfc_efx.ini
index 0a5c143..03890f3 100644
--- a/doc/guides/nics/features/sfc_efx.ini
+++ b/doc/guides/nics/features/sfc_efx.ini
@@ -26,6 +26,7 @@ L3 checksum offload  = Y
 L4 checksum offload  = Y
 Packet type parsing  = Y
 Rx descriptor status = Y
+Tx descriptor status = Y
 Basic stats          = Y
 Extended stats       = Y
 FW version           = Y
diff --git a/drivers/net/sfc/sfc_dp_tx.h b/drivers/net/sfc/sfc_dp_tx.h
index c1c3419..db2a70b 100644
--- a/drivers/net/sfc/sfc_dp_tx.h
+++ b/drivers/net/sfc/sfc_dp_tx.h
@@ -127,6 +127,12 @@ typedef void (sfc_dp_tx_qstop_t)(struct sfc_dp_txq *dp_txq,
  */
 typedef void (sfc_dp_tx_qreap_t)(struct sfc_dp_txq *dp_txq);
 
+/**
+ * Check Tx descriptor status
+ */
+typedef int (sfc_dp_tx_qdesc_status_t)(struct sfc_dp_txq *dp_txq,
+				       uint16_t offset);
+
 /** Transmit datapath definition */
 struct sfc_dp_tx {
 	struct sfc_dp			dp;
@@ -142,6 +148,7 @@ struct sfc_dp_tx {
 	sfc_dp_tx_qstop_t		*qstop;
 	sfc_dp_tx_qtx_ev_t		*qtx_ev;
 	sfc_dp_tx_qreap_t		*qreap;
+	sfc_dp_tx_qdesc_status_t	*qdesc_status;
 	eth_tx_burst_t			pkt_burst;
 };
 
diff --git a/drivers/net/sfc/sfc_ef10_tx.c b/drivers/net/sfc/sfc_ef10_tx.c
index da2b5ed..182fc23 100644
--- a/drivers/net/sfc/sfc_ef10_tx.c
+++ b/drivers/net/sfc/sfc_ef10_tx.c
@@ -565,6 +565,14 @@ struct sfc_ef10_txq {
 	txq->flags &= ~SFC_EF10_TXQ_STARTED;
 }
 
+static sfc_dp_tx_qdesc_status_t sfc_ef10_tx_qdesc_status;
+static int
+sfc_ef10_tx_qdesc_status(__rte_unused struct sfc_dp_txq *dp_txq,
+			 __rte_unused uint16_t offset)
+{
+	return -ENOTSUP;
+}
+
 struct sfc_dp_tx sfc_ef10_tx = {
 	.dp = {
 		.name		= SFC_KVARG_DATAPATH_EF10,
@@ -579,6 +587,7 @@ struct sfc_dp_tx sfc_ef10_tx = {
 	.qtx_ev			= sfc_ef10_tx_qtx_ev,
 	.qstop			= sfc_ef10_tx_qstop,
 	.qreap			= sfc_ef10_tx_qreap,
+	.qdesc_status		= sfc_ef10_tx_qdesc_status,
 	.pkt_burst		= sfc_ef10_xmit_pkts,
 };
 
@@ -594,5 +603,6 @@ struct sfc_dp_tx sfc_ef10_simple_tx = {
 	.qtx_ev			= sfc_ef10_tx_qtx_ev,
 	.qstop			= sfc_ef10_tx_qstop,
 	.qreap			= sfc_ef10_tx_qreap,
+	.qdesc_status		= sfc_ef10_tx_qdesc_status,
 	.pkt_burst		= sfc_ef10_simple_xmit_pkts,
 };
diff --git a/drivers/net/sfc/sfc_ethdev.c b/drivers/net/sfc/sfc_ethdev.c
index fe9ca30..a206952 100644
--- a/drivers/net/sfc/sfc_ethdev.c
+++ b/drivers/net/sfc/sfc_ethdev.c
@@ -1096,6 +1096,15 @@
 }
 
 static int
+sfc_tx_descriptor_status(void *queue, uint16_t offset)
+{
+	struct sfc_dp_txq *dp_txq = queue;
+	struct sfc_txq *txq = sfc_txq_by_dp_txq(dp_txq);
+
+	return txq->evq->sa->dp_tx->qdesc_status(dp_txq, offset);
+}
+
+static int
 sfc_rx_queue_start(struct rte_eth_dev *dev, uint16_t rx_queue_id)
 {
 	struct sfc_adapter *sa = dev->data->dev_private;
@@ -1479,6 +1488,7 @@
 	.rx_queue_count			= sfc_rx_queue_count,
 	.rx_descriptor_done		= sfc_rx_descriptor_done,
 	.rx_descriptor_status		= sfc_rx_descriptor_status,
+	.tx_descriptor_status		= sfc_tx_descriptor_status,
 	.tx_queue_setup			= sfc_tx_queue_setup,
 	.tx_queue_release		= sfc_tx_queue_release,
 	.flow_ctrl_get			= sfc_flow_ctrl_get,
diff --git a/drivers/net/sfc/sfc_tx.c b/drivers/net/sfc/sfc_tx.c
index fc439cb..bf59601 100644
--- a/drivers/net/sfc/sfc_tx.c
+++ b/drivers/net/sfc/sfc_tx.c
@@ -977,6 +977,44 @@ struct sfc_txq *
 	txq->flags &= ~SFC_EFX_TXQ_FLAG_STARTED;
 }
 
+static sfc_dp_tx_qdesc_status_t sfc_efx_tx_qdesc_status;
+static int
+sfc_efx_tx_qdesc_status(struct sfc_dp_txq *dp_txq, uint16_t offset)
+{
+	struct sfc_efx_txq *txq = sfc_efx_txq_by_dp_txq(dp_txq);
+
+	if (unlikely(offset > txq->ptr_mask))
+		return -EINVAL;
+
+	if (unlikely(offset >= EFX_TXQ_LIMIT(txq->ptr_mask + 1)))
+		return RTE_ETH_TX_DESC_UNAVAIL;
+
+	/*
+	 * Poll EvQ to derive up-to-date 'txq->pending' figure;
+	 * it is required for the queue to be running, but the
+	 * check is omitted because API design assumes that it
+	 * is the duty of the caller to satisfy all conditions
+	 */
+	SFC_ASSERT((txq->flags & SFC_EFX_TXQ_FLAG_RUNNING) ==
+		   SFC_EFX_TXQ_FLAG_RUNNING);
+	sfc_ev_qpoll(txq->evq);
+
+	/*
+	 * Ring tail is 'txq->pending', and although descriptors
+	 * between 'txq->completed' and 'txq->pending' are still
+	 * in use by the driver, they should be reported as DONE
+	 */
+	if (unlikely(offset < (txq->added - txq->pending)))
+		return RTE_ETH_TX_DESC_FULL;
+
+	/*
+	 * There is no separate return value for unused descriptors;
+	 * the latter will be reported as DONE because genuine DONE
+	 * descriptors will be freed anyway in SW on the next burst
+	 */
+	return RTE_ETH_TX_DESC_DONE;
+}
+
 struct sfc_dp_tx sfc_efx_tx = {
 	.dp = {
 		.name		= SFC_KVARG_DATAPATH_EFX,
@@ -991,5 +1029,6 @@ struct sfc_dp_tx sfc_efx_tx = {
 	.qstart			= sfc_efx_tx_qstart,
 	.qstop			= sfc_efx_tx_qstop,
 	.qreap			= sfc_efx_tx_qreap,
+	.qdesc_status		= sfc_efx_tx_qdesc_status,
 	.pkt_burst		= sfc_efx_xmit_pkts,
 };
-- 
1.8.2.3