[PATCH v2 1/3] ethdev: add API for direct rearm mode

[Feifei Wang <feifei.wang2@arm.com>]

Add API for enabling direct rearm mode and for mapping RX and TX
queues. Currently, the API supports 1:1(txq : rxq) mapping.

Furthermore, to avoid Rx load Tx data directly, add API called
'rte_eth_txq_data_get' to get Tx sw_ring and its information.

Suggested-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Suggested-by: Ruifeng Wang <ruifeng.wang@arm.com>
Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
---
 lib/ethdev/ethdev_driver.h   |  9 ++++
 lib/ethdev/ethdev_private.c  |  1 +
 lib/ethdev/rte_ethdev.c      | 37 ++++++++++++++
 lib/ethdev/rte_ethdev.h      | 95 ++++++++++++++++++++++++++++++++++++
 lib/ethdev/rte_ethdev_core.h |  5 ++
 lib/ethdev/version.map       |  4 ++
 6 files changed, 151 insertions(+)

diff --git a/lib/ethdev/ethdev_driver.h b/lib/ethdev/ethdev_driver.h
index 47a55a419e..14f52907c1 100644
--- a/lib/ethdev/ethdev_driver.h
+++ b/lib/ethdev/ethdev_driver.h
@@ -58,6 +58,8 @@ struct rte_eth_dev {
 	eth_rx_descriptor_status_t rx_descriptor_status;
 	/** Check the status of a Tx descriptor */
 	eth_tx_descriptor_status_t tx_descriptor_status;
+	/**  Use Tx mbufs for Rx to rearm */
+	eth_rx_direct_rearm_t rx_direct_rearm;
 
 	/**
 	 * Device data that is shared between primary and secondary processes
@@ -486,6 +488,11 @@ typedef int (*eth_rx_enable_intr_t)(struct rte_eth_dev *dev,
 typedef int (*eth_rx_disable_intr_t)(struct rte_eth_dev *dev,
 				    uint16_t rx_queue_id);
 
+/**< @internal Get Tx information of a transmit queue of an Ethernet device. */
+typedef void (*eth_txq_data_get_t)(struct rte_eth_dev *dev,
+				      uint16_t tx_queue_id,
+				      struct rte_eth_txq_data *txq_data);
+
 /** @internal Release memory resources allocated by given Rx/Tx queue. */
 typedef void (*eth_queue_release_t)(struct rte_eth_dev *dev,
 				    uint16_t queue_id);
@@ -1138,6 +1145,8 @@ struct eth_dev_ops {
 	eth_rxq_info_get_t         rxq_info_get;
 	/** Retrieve Tx queue information */
 	eth_txq_info_get_t         txq_info_get;
+	/** Get the address where Tx data is stored */
+	eth_txq_data_get_t         txq_data_get;
 	eth_burst_mode_get_t       rx_burst_mode_get; /**< Get Rx burst mode */
 	eth_burst_mode_get_t       tx_burst_mode_get; /**< Get Tx burst mode */
 	eth_fw_version_get_t       fw_version_get; /**< Get firmware version */
diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
index 48090c879a..bfe16c7d77 100644
--- a/lib/ethdev/ethdev_private.c
+++ b/lib/ethdev/ethdev_private.c
@@ -276,6 +276,7 @@ eth_dev_fp_ops_setup(struct rte_eth_fp_ops *fpo,
 	fpo->rx_queue_count = dev->rx_queue_count;
 	fpo->rx_descriptor_status = dev->rx_descriptor_status;
 	fpo->tx_descriptor_status = dev->tx_descriptor_status;
+	fpo->rx_direct_rearm = dev->rx_direct_rearm;
 
 	fpo->rxq.data = dev->data->rx_queues;
 	fpo->rxq.clbk = (void **)(uintptr_t)dev->post_rx_burst_cbs;
diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index 0c2c1088c0..0dccec2e4b 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -1648,6 +1648,43 @@ rte_eth_dev_is_removed(uint16_t port_id)
 	return ret;
 }
 
+int
+rte_eth_tx_queue_data_get(uint16_t port_id, uint16_t queue_id,
+			struct rte_eth_txq_data *txq_data)
+{
+	struct rte_eth_dev *dev;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+	dev = &rte_eth_devices[port_id];
+
+	if (queue_id >= dev->data->nb_tx_queues) {
+		RTE_ETHDEV_LOG(ERR, "Invalid Tx queue_id=%u\n", queue_id);
+		return -EINVAL;
+	}
+
+	if (txq_data == NULL) {
+		RTE_ETHDEV_LOG(ERR, "Cannot get ethdev port %u Tx queue %u data to NULL\n",
+			port_id, queue_id);
+		return -EINVAL;
+	}
+
+	if (dev->data->tx_queues == NULL ||
+			dev->data->tx_queues[queue_id] == NULL) {
+		RTE_ETHDEV_LOG(ERR,
+			   "Tx queue %"PRIu16" of device with port_id=%"
+			   PRIu16" has not been setup\n",
+			   queue_id, port_id);
+		return -EINVAL;
+	}
+
+	if (*dev->dev_ops->txq_data_get == NULL)
+		return -ENOTSUP;
+
+	dev->dev_ops->txq_data_get(dev, queue_id, txq_data);
+
+	return 0;
+}
+
 static int
 rte_eth_rx_queue_check_split(const struct rte_eth_rxseg_split *rx_seg,
 			     uint16_t n_seg, uint32_t *mbp_buf_size,
diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
index 2e783536c1..daf7f05d62 100644
--- a/lib/ethdev/rte_ethdev.h
+++ b/lib/ethdev/rte_ethdev.h
@@ -1949,6 +1949,23 @@ struct rte_eth_txq_info {
 	uint8_t queue_state;        /**< one of RTE_ETH_QUEUE_STATE_*. */
 } __rte_cache_min_aligned;
 
+/**
+ * @internal
+ * Structure used to hold pointers to internal ethdev Tx data.
+ * The main purpose is to load and store Tx queue data in direct rearm mode.
+ */
+struct rte_eth_txq_data {
+	uint64_t *offloads;
+	void *tx_sw_ring;
+	volatile void *tx_ring;
+	uint16_t *tx_next_dd;
+	uint16_t *nb_tx_free;
+	uint16_t nb_tx_desc;
+	uint16_t tx_rs_thresh;
+	uint16_t tx_free_thresh;
+} __rte_cache_min_aligned;
+
+
 /* Generic Burst mode flag definition, values can be ORed. */
 
 /**
@@ -4718,6 +4735,27 @@ int rte_eth_remove_rx_callback(uint16_t port_id, uint16_t queue_id,
 int rte_eth_remove_tx_callback(uint16_t port_id, uint16_t queue_id,
 		const struct rte_eth_rxtx_callback *user_cb);
 
+/**
+ * Get the address which Tx data is stored.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param queue_id
+ *   The Tx queue on the Ethernet device for which information
+ *   will be retrieved.
+ * @param txq_data
+ *   A pointer to a structure of type *rte_eth_txq_data* to be filled.
+ *
+ * @return
+ *   - 0: Success
+ *   - -ENODEV:  If *port_id* is invalid.
+ *   - -ENOTSUP: routine is not supported by the device PMD.
+ *   - -EINVAL:  The queue_id is out of range.
+ */
+__rte_experimental
+int rte_eth_tx_queue_data_get(uint16_t port_id, uint16_t queue_id,
+		struct rte_eth_txq_data *txq_data);
+
 /**
  * Retrieve information about given port's Rx queue.
  *
@@ -6209,6 +6247,63 @@ rte_eth_tx_buffer(uint16_t port_id, uint16_t queue_id,
 	return rte_eth_tx_buffer_flush(port_id, queue_id, buffer);
 }
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Put Tx buffers into Rx sw-ring and rearm descs.
+ *
+ * @param port_id
+ *   Port identifying the receive side.
+ * @param queue_id
+ *   The index of the transmit queue identifying the receive side.
+ *   The value must be in the range [0, nb_rx_queue - 1] previously supplied
+ *   to rte_eth_dev_configure().
+ * @param txq_data
+ *   A pointer to a structure of type *rte_eth_txq_data* to be filled.
+ * @return
+ *   The number of direct-rearmed buffers.
+ */
+__rte_experimental
+static __rte_always_inline uint16_t
+rte_eth_rx_direct_rearm(uint16_t port_id, uint16_t queue_id,
+		struct rte_eth_txq_data *txq_data)
+{
+	uint16_t nb_rearm;
+	struct rte_eth_fp_ops *p;
+	void *qd;
+
+#ifdef RTE_ETHDEV_DEBUG_RX
+	if (port_id >= RTE_MAX_ETHPORTS ||
+			queue_id >= RTE_MAX_QUEUES_PER_PORT) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid port_id=%u or queue_id=%u\n",
+			port_id, queue_id);
+		return 0;
+	}
+#endif
+
+	p = &rte_eth_fp_ops[port_id];
+	qd = p->rxq.data[queue_id];
+
+#ifdef RTE_ETHDEV_DEBUG_RX
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
+
+	if (qd == NULL) {
+		RTE_ETHDEV_LOG(ERR, "Invalid Rx queue_id=%u for port_id=%u\n",
+			queue_id, port_id);
+		return 0;
+	}
+
+	if (!p->rx_direct_rearm)
+		return -ENOTSUP;
+#endif
+
+	nb_rearm = p->rx_direct_rearm(qd, txq_data);
+
+	return nb_rearm;
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/ethdev/rte_ethdev_core.h b/lib/ethdev/rte_ethdev_core.h
index dcf8adab92..6a328e2481 100644
--- a/lib/ethdev/rte_ethdev_core.h
+++ b/lib/ethdev/rte_ethdev_core.h
@@ -56,6 +56,9 @@ typedef int (*eth_rx_descriptor_status_t)(void *rxq, uint16_t offset);
 /** @internal Check the status of a Tx descriptor */
 typedef int (*eth_tx_descriptor_status_t)(void *txq, uint16_t offset);
 
+/** @internal Put Tx buffers into Rx sw-ring and rearm descs */
+typedef uint16_t (*eth_rx_direct_rearm_t)(void *rxq, struct rte_eth_txq_data *txq_data);
+
 /**
  * @internal
  * Structure used to hold opaque pointers to internal ethdev Rx/Tx
@@ -90,6 +93,8 @@ struct rte_eth_fp_ops {
 	eth_rx_queue_count_t rx_queue_count;
 	/** Check the status of a Rx descriptor. */
 	eth_rx_descriptor_status_t rx_descriptor_status;
+	/** Put Tx buffers into Rx sw-ring and rearm descs */
+	eth_rx_direct_rearm_t rx_direct_rearm;
 	/** Rx queues data. */
 	struct rte_ethdev_qdata rxq;
 	uintptr_t reserved1[3];
diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map
index 03f52fee91..69e4c376d3 100644
--- a/lib/ethdev/version.map
+++ b/lib/ethdev/version.map
@@ -285,6 +285,10 @@ EXPERIMENTAL {
 	rte_mtr_color_in_protocol_priority_get;
 	rte_mtr_color_in_protocol_set;
 	rte_mtr_meter_vlan_table_update;
+
+	# added in 22.11
+	rte_eth_tx_queue_data_get;
+	rte_eth_rx_direct_rearm;
 };
 
 INTERNAL {
-- 
2.25.1