[dpdk-dev] [PATCH v2 05/17] net/mlx5: create clock queue for packet pacing

[Viacheslav Ovsiienko <viacheslavo@mellanox.com>]

This patch creates the special completion queue providing
reference completions to schedule packet send from
other transmitting queues.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>
---
 drivers/net/mlx5/Makefile        |   1 +
 drivers/net/mlx5/linux/mlx5_os.c |   3 +
 drivers/net/mlx5/meson.build     |   1 +
 drivers/net/mlx5/mlx5.c          |   2 +
 drivers/net/mlx5/mlx5.h          |  47 ++++
 drivers/net/mlx5/mlx5_defs.h     |   7 +
 drivers/net/mlx5/mlx5_trigger.c  |  16 +-
 drivers/net/mlx5/mlx5_txpp.c     | 449 +++++++++++++++++++++++++++++++++++++++
 8 files changed, 521 insertions(+), 5 deletions(-)
 create mode 100644 drivers/net/mlx5/mlx5_txpp.c

diff --git a/drivers/net/mlx5/Makefile b/drivers/net/mlx5/Makefile
index a458402..9eaac6b 100644
--- a/drivers/net/mlx5/Makefile
+++ b/drivers/net/mlx5/Makefile
@@ -11,6 +11,7 @@ LIB = librte_pmd_mlx5.a
 SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_rxq.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_txq.c
+SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_txpp.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_rxtx.c
 ifneq ($(filter y,$(CONFIG_RTE_ARCH_X86_64) \
 			$(CONFIG_RTE_ARCH_PPC_64) \
diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
index 63e9350..ea36309 100644
--- a/drivers/net/mlx5/linux/mlx5_os.c
+++ b/drivers/net/mlx5/linux/mlx5_os.c
@@ -1869,6 +1869,9 @@
 {
 	int dbmap_env;
 	int err = 0;
+
+	sh->numa_node = spawn->pci_dev->device.numa_node;
+	pthread_mutex_init(&sh->txpp.mutex, NULL);
 	/*
 	 * Configure environment variable "MLX5_BF_SHUT_UP"
 	 * before the device creation. The rdma_core library
diff --git a/drivers/net/mlx5/meson.build b/drivers/net/mlx5/meson.build
index e95ce02..c06b153 100644
--- a/drivers/net/mlx5/meson.build
+++ b/drivers/net/mlx5/meson.build
@@ -26,6 +26,7 @@ sources = files(
 	'mlx5_stats.c',
 	'mlx5_trigger.c',
 	'mlx5_txq.c',
+	'mlx5_txpp.c',
 	'mlx5_vlan.c',
 	'mlx5_utils.c',
 )
diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c
index 71e59ac..10196ac 100644
--- a/drivers/net/mlx5/mlx5.c
+++ b/drivers/net/mlx5/mlx5.c
@@ -767,6 +767,7 @@ struct mlx5_dev_ctx_shared *
 	pthread_mutex_unlock(&mlx5_dev_ctx_list_mutex);
 	return sh;
 error:
+	pthread_mutex_destroy(&sh->txpp.mutex);
 	pthread_mutex_unlock(&mlx5_dev_ctx_list_mutex);
 	MLX5_ASSERT(sh);
 	if (sh->cnt_id_tbl) {
@@ -856,6 +857,7 @@ struct mlx5_dev_ctx_shared *
 		claim_zero(mlx5_glue->close_device(sh->ctx));
 	if (sh->flow_id_pool)
 		mlx5_flow_id_pool_release(sh->flow_id_pool);
+	pthread_mutex_destroy(&sh->txpp.mutex);
 	rte_free(sh);
 exit:
 	pthread_mutex_unlock(&mlx5_dev_ctx_list_mutex);
diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index c760aff..0b73b2a 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -531,6 +531,44 @@ struct mlx5_flow_id_pool {
 	uint32_t max_id; /**< Maximum id can be allocated from the pool. */
 };
 
+/* Tx pacing queue structure - for Clock and Rearm queues. */
+struct mlx5_txpp_wq {
+	/* Completion Queue related data.*/
+	struct mlx5_devx_obj *cq;
+	struct mlx5dv_devx_umem *cq_umem;
+	union {
+		volatile void *cq_buf;
+		volatile struct mlx5_cqe *cqes;
+	};
+	volatile uint32_t *cq_dbrec;
+	uint32_t cq_ci:24;
+	uint32_t arm_sn:2;
+	/* Send Queue related data.*/
+	struct mlx5_devx_obj *sq;
+	struct mlx5dv_devx_umem *sq_umem;
+	union {
+		volatile void *sq_buf;
+		volatile struct mlx5_wqe *wqes;
+	};
+	uint16_t sq_size; /* Number of WQEs in the queue. */
+	uint16_t sq_ci; /* Next WQE to execute. */
+	volatile uint32_t *sq_dbrec;
+};
+
+/* Tx packet pacing structure. */
+struct mlx5_dev_txpp {
+	pthread_mutex_t mutex; /* Pacing create/destroy mutex. */
+	uint32_t refcnt; /* Pacing reference counter. */
+	uint32_t freq; /* Timestamp frequency, Hz. */
+	uint32_t tick; /* Completion tick duration in nanoseconds. */
+	uint32_t test; /* Packet pacing test mode. */
+	int32_t skew; /* Scheduling skew. */
+	uint32_t eqn; /* Event Queue number. */
+	struct rte_intr_handle intr_handle; /* Periodic interrupt. */
+	struct mlx5dv_devx_event_channel *echan; /* Event Channel. */
+	struct mlx5_txpp_wq clock_queue; /* Clock Queue. */
+};
+
 /*
  * Shared Infiniband device context for Master/Representors
  * which belong to same IB device with multiple IB ports.
@@ -547,9 +585,12 @@ struct mlx5_dev_ctx_shared {
 	char ibdev_name[DEV_SYSFS_NAME_MAX]; /* SYSFS dev name. */
 	char ibdev_path[DEV_SYSFS_PATH_MAX]; /* SYSFS dev path for secondary */
 	struct mlx5_dev_attr device_attr; /* Device properties. */
+	int numa_node; /* Numa node of backing physical device. */
 	LIST_ENTRY(mlx5_dev_ctx_shared) mem_event_cb;
 	/**< Called by memory event callback. */
 	struct mlx5_mr_share_cache share_cache;
+	/* Packet pacing related structure. */
+	struct mlx5_dev_txpp txpp;
 	/* Shared DV/DR flow data section. */
 	pthread_mutex_t dv_mutex; /* DV context mutex. */
 	uint32_t dv_meta_mask; /* flow META metadata supported mask. */
@@ -622,6 +663,7 @@ struct mlx5_priv {
 	unsigned int representor:1; /* Device is a port representor. */
 	unsigned int master:1; /* Device is a E-Switch master. */
 	unsigned int dr_shared:1; /* DV/DR data is shared. */
+	unsigned int txpp_en:1; /* Tx packet pacing enabled. */
 	unsigned int counter_fallback:1; /* Use counter fallback management. */
 	unsigned int mtr_en:1; /* Whether support meter. */
 	unsigned int mtr_reg_share:1; /* Whether support meter REG_C share. */
@@ -944,4 +986,9 @@ int mlx5_os_read_dev_stat(struct mlx5_priv *priv,
 void mlx5_os_stats_init(struct rte_eth_dev *dev);
 void mlx5_os_set_reg_mr_cb(mlx5_reg_mr_t *reg_mr_cb,
 			   mlx5_dereg_mr_t *dereg_mr_cb);
+/* mlx5_txpp.c */
+
+int mlx5_txpp_start(struct rte_eth_dev *dev);
+void mlx5_txpp_stop(struct rte_eth_dev *dev);
+
 #endif /* RTE_PMD_MLX5_H_ */
diff --git a/drivers/net/mlx5/mlx5_defs.h b/drivers/net/mlx5/mlx5_defs.h
index 260f584..07a2b59 100644
--- a/drivers/net/mlx5/mlx5_defs.h
+++ b/drivers/net/mlx5/mlx5_defs.h
@@ -171,6 +171,13 @@
 #define MLX5_TXDB_NCACHED 1
 #define MLX5_TXDB_HEURISTIC 2
 
+/* Tx accurate scheduling on timestamps parameters. */
+#define MLX5_TXPP_CLKQ_SIZE 1
+/* The minimal size test packet to put into one WQE, padded by HW. */
+#define MLX5_TXPP_TEST_PKT_SIZE (sizeof(struct rte_ether_hdr) +	\
+				 sizeof(struct rte_ipv4_hdr))
+
+
 /* Size of the simple hash table for metadata register table. */
 #define MLX5_FLOW_MREG_HTABLE_SZ 4096
 #define MLX5_FLOW_MREG_HNAME "MARK_COPY_TABLE"
diff --git a/drivers/net/mlx5/mlx5_trigger.c b/drivers/net/mlx5/mlx5_trigger.c
index ef74609..ca25ad9 100644
--- a/drivers/net/mlx5/mlx5_trigger.c
+++ b/drivers/net/mlx5/mlx5_trigger.c
@@ -288,25 +288,29 @@
 			return -rte_errno;
 		}
 	}
+	ret = mlx5_txpp_start(dev);
+	if (ret) {
+		DRV_LOG(ERR, "port %u Tx packet pacing init failed: %s",
+			dev->data->port_id, strerror(rte_errno));
+		goto error;
+	}
 	ret = mlx5_txq_start(dev);
 	if (ret) {
 		DRV_LOG(ERR, "port %u Tx queue allocation failed: %s",
 			dev->data->port_id, strerror(rte_errno));
-		return -rte_errno;
+		goto error;
 	}
 	ret = mlx5_rxq_start(dev);
 	if (ret) {
 		DRV_LOG(ERR, "port %u Rx queue allocation failed: %s",
 			dev->data->port_id, strerror(rte_errno));
-		mlx5_txq_stop(dev);
-		return -rte_errno;
+		goto error;
 	}
 	ret = mlx5_hairpin_bind(dev);
 	if (ret) {
 		DRV_LOG(ERR, "port %u hairpin binding failed: %s",
 			dev->data->port_id, strerror(rte_errno));
-		mlx5_txq_stop(dev);
-		return -rte_errno;
+		goto error;
 	}
 	/* Set started flag here for the following steps like control flow. */
 	dev->data->dev_started = 1;
@@ -362,6 +366,7 @@
 	mlx5_traffic_disable(dev);
 	mlx5_txq_stop(dev);
 	mlx5_rxq_stop(dev);
+	mlx5_txpp_stop(dev); /* Stop last. */
 	rte_errno = ret; /* Restore rte_errno. */
 	return -rte_errno;
 }
@@ -398,6 +403,7 @@
 	priv->sh->port[priv->dev_port - 1].devx_ih_port_id = RTE_MAX_ETHPORTS;
 	mlx5_txq_stop(dev);
 	mlx5_rxq_stop(dev);
+	mlx5_txpp_stop(dev);
 }
 
 /**
diff --git a/drivers/net/mlx5/mlx5_txpp.c b/drivers/net/mlx5/mlx5_txpp.c
new file mode 100644
index 0000000..382bd20
--- /dev/null
+++ b/drivers/net/mlx5/mlx5_txpp.c
@@ -0,0 +1,449 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2020 Mellanox Technologies, Ltd
+ */
+#include <rte_ether.h>
+#include <rte_ethdev_driver.h>
+#include <rte_interrupts.h>
+#include <rte_alarm.h>
+#include <rte_malloc.h>
+
+#include "mlx5.h"
+#include "mlx5_rxtx.h"
+
+/* Destroy Event Queue Notification Channel. */
+static void
+mlx5_txpp_destroy_eqn(struct mlx5_dev_ctx_shared *sh)
+{
+	if (sh->txpp.echan) {
+		mlx5_glue->devx_destroy_event_channel(sh->txpp.echan);
+		sh->txpp.echan = NULL;
+	}
+	sh->txpp.eqn = 0;
+}
+
+/* Create Event Queue Notification Channel. */
+static int
+mlx5_txpp_create_eqn(struct mlx5_dev_ctx_shared *sh)
+{
+	uint32_t lcore;
+
+	MLX5_ASSERT(!sh->txpp.echan);
+	lcore = (uint32_t)rte_lcore_to_cpu_id(-1);
+	if (mlx5_glue->devx_query_eqn(sh->ctx, lcore, &sh->txpp.eqn)) {
+		rte_errno = errno;
+		DRV_LOG(ERR, "Failed to query EQ number %d.", rte_errno);
+		sh->txpp.eqn = 0;
+		return -rte_errno;
+	}
+	sh->txpp.echan = mlx5_glue->devx_create_event_channel(sh->ctx,
+			MLX5DV_DEVX_CREATE_EVENT_CHANNEL_FLAGS_OMIT_EV_DATA);
+	if (!sh->txpp.echan) {
+		sh->txpp.eqn = 0;
+		rte_errno = errno;
+		DRV_LOG(ERR, "Failed to create event channel %d.",
+			rte_errno);
+		return -rte_errno;
+	}
+	return 0;
+}
+
+static void
+mlx5_txpp_destroy_clock_queue(struct mlx5_dev_ctx_shared *sh)
+{
+	struct mlx5_txpp_wq *wq = &sh->txpp.clock_queue;
+
+	if (wq->sq)
+		claim_zero(mlx5_devx_cmd_destroy(wq->sq));
+	if (wq->sq_umem)
+		claim_zero(mlx5_glue->devx_umem_dereg(wq->sq_umem));
+	if (wq->sq_buf)
+		rte_free((void *)(uintptr_t)wq->sq_buf);
+	if (wq->cq)
+		claim_zero(mlx5_devx_cmd_destroy(wq->cq));
+	if (wq->cq_umem)
+		claim_zero(mlx5_glue->devx_umem_dereg(wq->cq_umem));
+	if (wq->cq_buf)
+		rte_free((void *)(uintptr_t)wq->cq_buf);
+	memset(wq, 0, sizeof(*wq));
+}
+
+static void
+mlx5_txpp_fill_wqe_clock_queue(struct mlx5_dev_ctx_shared *sh)
+{
+	struct mlx5_txpp_wq *wq = &sh->txpp.clock_queue;
+	struct mlx5_wqe *wqe = (struct mlx5_wqe *)(uintptr_t)wq->wqes;
+	struct mlx5_wqe_cseg *cs = &wqe->cseg;
+	uint32_t wqe_size, opcode, i;
+	uint8_t *dst;
+
+	/* For test purposes fill the WQ with SEND inline packet. */
+	if (sh->txpp.test) {
+		wqe_size = RTE_ALIGN(MLX5_TXPP_TEST_PKT_SIZE +
+				     MLX5_WQE_CSEG_SIZE +
+				     2 * MLX5_WQE_ESEG_SIZE -
+				     MLX5_ESEG_MIN_INLINE_SIZE,
+				     MLX5_WSEG_SIZE);
+		opcode = MLX5_OPCODE_SEND;
+	} else {
+		wqe_size = MLX5_WSEG_SIZE;
+		opcode = MLX5_OPCODE_NOP;
+	}
+	cs->opcode = rte_cpu_to_be_32(opcode | 0); /* Index is ignored. */
+	cs->sq_ds = rte_cpu_to_be_32((wq->sq->id << 8) |
+				     (wqe_size / MLX5_WSEG_SIZE));
+	cs->flags = RTE_BE32(MLX5_COMP_ALWAYS << MLX5_COMP_MODE_OFFSET);
+	cs->misc = RTE_BE32(0);
+	wqe_size = RTE_ALIGN(wqe_size, MLX5_WQE_SIZE);
+	if (sh->txpp.test) {
+		struct mlx5_wqe_eseg *es = &wqe->eseg;
+		struct rte_ether_hdr *eth_hdr;
+		struct rte_ipv4_hdr *ip_hdr;
+		struct rte_udp_hdr *udp_hdr;
+
+		/* Build the inline test packet pattern. */
+		MLX5_ASSERT(wqe_size <= MLX5_WQE_SIZE_MAX);
+		MLX5_ASSERT(MLX5_TXPP_TEST_PKT_SIZE >=
+				(sizeof(struct rte_ether_hdr) +
+				 sizeof(struct rte_ipv4_hdr)));
+		es->flags = 0;
+		es->cs_flags = MLX5_ETH_WQE_L3_CSUM | MLX5_ETH_WQE_L4_CSUM;
+		es->swp_offs = 0;
+		es->metadata = 0;
+		es->swp_flags = 0;
+		es->mss = 0;
+		es->inline_hdr_sz = RTE_BE16(MLX5_TXPP_TEST_PKT_SIZE);
+		/* Build test packet L2 header (Ethernet). */
+		dst = (uint8_t *)&es->inline_data;
+		eth_hdr = (struct rte_ether_hdr *)dst;
+		rte_eth_random_addr(&eth_hdr->d_addr.addr_bytes[0]);
+		rte_eth_random_addr(&eth_hdr->s_addr.addr_bytes[0]);
+		eth_hdr->ether_type = rte_cpu_to_be_16(RTE_ETHER_TYPE_IPV4);
+		/* Build test packet L3 header (IP v4). */
+		dst += sizeof(struct rte_ether_hdr);
+		ip_hdr = (struct rte_ipv4_hdr *)dst;
+		ip_hdr->version_ihl = RTE_IPV4_VHL_DEF;
+		ip_hdr->type_of_service = 0;
+		ip_hdr->fragment_offset = 0;
+		ip_hdr->time_to_live = 64;
+		ip_hdr->next_proto_id = IPPROTO_UDP;
+		ip_hdr->packet_id = 0;
+		ip_hdr->total_length = RTE_BE16(MLX5_TXPP_TEST_PKT_SIZE -
+						sizeof(struct rte_ether_hdr));
+		/* use RFC5735 / RFC2544 reserved network test addresses */
+		ip_hdr->src_addr = RTE_BE32((198U << 24) | (18 << 16) |
+					    (0 << 8) | 1);
+		ip_hdr->dst_addr = RTE_BE32((198U << 24) | (18 << 16) |
+					    (0 << 8) | 2);
+		if (MLX5_TXPP_TEST_PKT_SIZE <
+					(sizeof(struct rte_ether_hdr) +
+					 sizeof(struct rte_ipv4_hdr) +
+					 sizeof(struct rte_udp_hdr)))
+			goto wcopy;
+		/* Build test packet L4 header (UDP). */
+		dst += sizeof(struct rte_ipv4_hdr);
+		udp_hdr = (struct rte_udp_hdr *)dst;
+		udp_hdr->src_port = RTE_BE16(9); /* RFC863 Discard. */
+		udp_hdr->dst_port = RTE_BE16(9);
+		udp_hdr->dgram_len = RTE_BE16(MLX5_TXPP_TEST_PKT_SIZE -
+					      sizeof(struct rte_ether_hdr) -
+					      sizeof(struct rte_ipv4_hdr));
+		udp_hdr->dgram_cksum = 0;
+		/* Fill the test packet data. */
+		dst += sizeof(struct rte_udp_hdr);
+		for (i = sizeof(struct rte_ether_hdr) +
+			sizeof(struct rte_ipv4_hdr) +
+			sizeof(struct rte_udp_hdr);
+				i < MLX5_TXPP_TEST_PKT_SIZE; i++)
+			*dst++ = (uint8_t)(i & 0xFF);
+	}
+wcopy:
+	/* Duplicate the pattern to the next WQEs. */
+	dst = (uint8_t *)(uintptr_t)wq->sq_buf;
+	for (i = 1; i < MLX5_TXPP_CLKQ_SIZE; i++) {
+		dst += wqe_size;
+		rte_memcpy(dst, (void *)(uintptr_t)wq->sq_buf, wqe_size);
+	}
+}
+
+/* Creates the Clock Queue for packet pacing, returns zero on success. */
+static int
+mlx5_txpp_create_clock_queue(struct mlx5_dev_ctx_shared *sh)
+{
+	struct mlx5_devx_create_sq_attr sq_attr = { 0 };
+	struct mlx5_devx_modify_sq_attr msq_attr = { 0 };
+	struct mlx5_devx_cq_attr cq_attr = { 0 };
+	struct mlx5_txpp_wq *wq = &sh->txpp.clock_queue;
+	size_t page_size = sysconf(_SC_PAGESIZE);
+	uint32_t umem_size, umem_dbrec;
+	int ret;
+
+	/* Allocate memory buffer for CQEs and doorbell record. */
+	umem_size = sizeof(struct mlx5_cqe) * MLX5_TXPP_CLKQ_SIZE;
+	umem_dbrec = RTE_ALIGN(umem_size, MLX5_DBR_SIZE);
+	umem_size += MLX5_DBR_SIZE;
+	wq->cq_buf = rte_zmalloc_socket(__func__, umem_size,
+					page_size, sh->numa_node);
+	if (!wq->cq_buf) {
+		DRV_LOG(ERR, "Failed to allocate memory for Clock Queue.");
+		return -ENOMEM;
+	}
+	/* Register allocated buffer in user space with DevX. */
+	wq->cq_umem = mlx5_glue->devx_umem_reg(sh->ctx,
+					       (void *)(uintptr_t)wq->cq_buf,
+					       umem_size,
+					       IBV_ACCESS_LOCAL_WRITE);
+	if (!wq->cq_umem) {
+		rte_errno = errno;
+		DRV_LOG(ERR, "Failed to register umem for Clock Queue.");
+		goto error;
+	}
+	/* Create completion queue object for Clock Queue. */
+	cq_attr.cqe_size = (sizeof(struct mlx5_cqe) == 128) ?
+			    MLX5_CQE_SIZE_128B : MLX5_CQE_SIZE_64B;
+	cq_attr.use_first_only = 1;
+	cq_attr.overrun_ignore = 1;
+	cq_attr.uar_page_id = sh->tx_uar->page_id;
+	cq_attr.eqn = sh->txpp.eqn;
+	cq_attr.q_umem_valid = 1;
+	cq_attr.q_umem_offset = 0;
+	cq_attr.q_umem_id = wq->cq_umem->umem_id;
+	cq_attr.db_umem_valid = 1;
+	cq_attr.db_umem_offset = umem_dbrec;
+	cq_attr.db_umem_id = wq->cq_umem->umem_id;
+	cq_attr.log_cq_size = rte_log2_u32(MLX5_TXPP_CLKQ_SIZE);
+	cq_attr.log_page_size = rte_log2_u32(page_size);
+	wq->cq = mlx5_devx_cmd_create_cq(sh->ctx, &cq_attr);
+	if (!wq->cq) {
+		rte_errno = errno;
+		DRV_LOG(ERR, "Failed to create CQ for Clock Queue.");
+		goto error;
+	}
+	wq->cq_dbrec = RTE_PTR_ADD(wq->cq_buf, umem_dbrec);
+	wq->cq_ci = 0;
+	/* Allocate memory buffer for Send Queue WQEs. */
+	if (sh->txpp.test) {
+		wq->sq_size = RTE_ALIGN(MLX5_TXPP_TEST_PKT_SIZE +
+					MLX5_WQE_CSEG_SIZE +
+					2 * MLX5_WQE_ESEG_SIZE -
+					MLX5_ESEG_MIN_INLINE_SIZE,
+					MLX5_WQE_SIZE) / MLX5_WQE_SIZE;
+		wq->sq_size *= MLX5_TXPP_CLKQ_SIZE;
+	} else {
+		wq->sq_size = MLX5_TXPP_CLKQ_SIZE;
+	}
+	/* There should not be WQE leftovers in the cyclic queue. */
+	MLX5_ASSERT(wq->sq_size == (1 << log2above(wq->sq_size)));
+	umem_size =  MLX5_WQE_SIZE * wq->sq_size;
+	umem_dbrec = RTE_ALIGN(umem_size, MLX5_DBR_SIZE);
+	umem_size += MLX5_DBR_SIZE;
+	wq->sq_buf = rte_zmalloc_socket(__func__, umem_size,
+					page_size, sh->numa_node);
+	if (!wq->sq_buf) {
+		DRV_LOG(ERR, "Failed to allocate memory for Clock Queue.");
+		rte_errno = ENOMEM;
+		goto error;
+	}
+	/* Register allocated buffer in user space with DevX. */
+	wq->sq_umem = mlx5_glue->devx_umem_reg(sh->ctx,
+					       (void *)(uintptr_t)wq->sq_buf,
+					       umem_size,
+					       IBV_ACCESS_LOCAL_WRITE);
+	if (!wq->sq_umem) {
+		rte_errno = errno;
+		DRV_LOG(ERR, "Failed to register umem for Clock Queue.");
+		goto error;
+	}
+	/* Create send queue object for Clock Queue. */
+	if (sh->txpp.test) {
+		sq_attr.tis_lst_sz = 1;
+		sq_attr.tis_num = sh->tis->id;
+		sq_attr.non_wire = 0;
+		sq_attr.static_sq_wq = 1;
+	} else {
+		sq_attr.non_wire = 1;
+		sq_attr.static_sq_wq = 1;
+	}
+	sq_attr.state = MLX5_SQC_STATE_RST;
+	sq_attr.cqn = wq->cq->id;
+	sq_attr.wq_attr.cd_slave = 1;
+	sq_attr.wq_attr.uar_page = sh->tx_uar->page_id;
+	sq_attr.wq_attr.wq_type = MLX5_WQ_TYPE_CYCLIC;
+	sq_attr.wq_attr.pd = sh->pdn;
+	sq_attr.wq_attr.log_wq_stride = rte_log2_u32(MLX5_WQE_SIZE);
+	sq_attr.wq_attr.log_wq_sz = rte_log2_u32(wq->sq_size);
+	sq_attr.wq_attr.dbr_umem_valid = 1;
+	sq_attr.wq_attr.dbr_addr = umem_dbrec;
+	sq_attr.wq_attr.dbr_umem_id = wq->sq_umem->umem_id;
+	sq_attr.wq_attr.wq_umem_valid = 1;
+	sq_attr.wq_attr.wq_umem_id = wq->sq_umem->umem_id;
+	/* umem_offset must be zero for static_sq_wq queue. */
+	sq_attr.wq_attr.wq_umem_offset = 0;
+	wq->sq = mlx5_devx_cmd_create_sq(sh->ctx, &sq_attr);
+	if (!wq->sq) {
+		rte_errno = errno;
+		DRV_LOG(ERR, "Failed to create SQ for Clock Queue.");
+		goto error;
+	}
+	wq->sq_dbrec = RTE_PTR_ADD(wq->sq_buf, umem_dbrec +
+				   MLX5_SND_DBR * sizeof(uint32_t));
+	/* Build the WQEs in the Send Queue before goto Ready state. */
+	mlx5_txpp_fill_wqe_clock_queue(sh);
+	/* Change queue state to ready. */
+	msq_attr.sq_state = MLX5_SQC_STATE_RST;
+	msq_attr.state = MLX5_SQC_STATE_RDY;
+	wq->sq_ci = 0;
+	ret = mlx5_devx_cmd_modify_sq(wq->sq, &msq_attr);
+	if (ret) {
+		DRV_LOG(ERR, "Failed to set SQ ready state Clock Queue.");
+		goto error;
+	}
+	return 0;
+error:
+	ret = -rte_errno;
+	mlx5_txpp_destroy_clock_queue(sh);
+	rte_errno = -ret;
+	return ret;
+}
+
+/*
+ * The routine initializes the packet pacing infrastructure:
+ * - allocates PP context
+ * - Clock CQ/SQ
+ * - Rearm CQ/SQ
+ * - attaches rearm interrupt handler
+ *
+ * Returns 0 on success, negative otherwise
+ */
+static int
+mlx5_txpp_create(struct mlx5_dev_ctx_shared *sh, struct mlx5_priv *priv)
+{
+	int tx_pp = priv->config.tx_pp;
+	int ret;
+
+	/* Store the requested pacing parameters. */
+	sh->txpp.tick = tx_pp >= 0 ? tx_pp : -tx_pp;
+	sh->txpp.test = !!(tx_pp < 0);
+	sh->txpp.skew = priv->config.tx_skew;
+	sh->txpp.freq = priv->config.hca_attr.dev_freq_khz;
+	ret = mlx5_txpp_create_eqn(sh);
+	if (ret)
+		goto exit;
+	ret = mlx5_txpp_create_clock_queue(sh);
+	if (ret)
+		goto exit;
+exit:
+	if (ret) {
+		mlx5_txpp_destroy_clock_queue(sh);
+		mlx5_txpp_destroy_eqn(sh);
+		sh->txpp.tick = 0;
+		sh->txpp.test = 0;
+		sh->txpp.skew = 0;
+	}
+	return ret;
+}
+
+/*
+ * The routine destroys the packet pacing infrastructure:
+ * - detaches rearm interrupt handler
+ * - Rearm CQ/SQ
+ * - Clock CQ/SQ
+ * - PP context
+ */
+static void
+mlx5_txpp_destroy(struct mlx5_dev_ctx_shared *sh)
+{
+	mlx5_txpp_destroy_clock_queue(sh);
+	mlx5_txpp_destroy_eqn(sh);
+	sh->txpp.tick = 0;
+	sh->txpp.test = 0;
+	sh->txpp.skew = 0;
+}
+
+/**
+ * Creates and starts packet pacing infrastructure on specified device.
+ *
+ * @param dev
+ *   Pointer to Ethernet device structure.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx5_txpp_start(struct rte_eth_dev *dev)
+{
+	struct mlx5_priv *priv = dev->data->dev_private;
+	struct mlx5_dev_ctx_shared *sh = priv->sh;
+	int err = 0;
+	int ret;
+
+	if (!priv->config.tx_pp) {
+		/* Packet pacing is not requested for the device. */
+		MLX5_ASSERT(priv->txpp_en == 0);
+		return 0;
+	}
+	if (priv->txpp_en) {
+		/* Packet pacing is already enabled for the device. */
+		MLX5_ASSERT(sh->txpp.refcnt);
+		return 0;
+	}
+	if (priv->config.tx_pp > 0) {
+		ret = rte_mbuf_dynflag_lookup
+				(RTE_MBUF_DYNFLAG_TX_TIMESTAMP_NAME, NULL);
+		if (ret < 0)
+			return 0;
+	}
+	ret = pthread_mutex_lock(&sh->txpp.mutex);
+	MLX5_ASSERT(!ret);
+	RTE_SET_USED(ret);
+	if (sh->txpp.refcnt) {
+		priv->txpp_en = 1;
+		++sh->txpp.refcnt;
+	} else {
+		err = mlx5_txpp_create(sh, priv);
+		if (!err) {
+			MLX5_ASSERT(sh->txpp.tick);
+			priv->txpp_en = 1;
+			sh->txpp.refcnt = 1;
+		} else {
+			rte_errno = -err;
+		}
+	}
+	ret = pthread_mutex_unlock(&sh->txpp.mutex);
+	MLX5_ASSERT(!ret);
+	RTE_SET_USED(ret);
+	return err;
+}
+
+/**
+ * Stops and destroys packet pacing infrastructure on specified device.
+ *
+ * @param dev
+ *   Pointer to Ethernet device structure.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+void
+mlx5_txpp_stop(struct rte_eth_dev *dev)
+{
+	struct mlx5_priv *priv = dev->data->dev_private;
+	struct mlx5_dev_ctx_shared *sh = priv->sh;
+	int ret;
+
+	if (!priv->txpp_en) {
+		/* Packet pacing is already disabled for the device. */
+		return;
+	}
+	priv->txpp_en = 0;
+	ret = pthread_mutex_lock(&sh->txpp.mutex);
+	MLX5_ASSERT(!ret);
+	RTE_SET_USED(ret);
+	MLX5_ASSERT(sh->txpp.refcnt);
+	if (!sh->txpp.refcnt || --sh->txpp.refcnt)
+		return;
+	/* No references any more, do actual destroy. */
+	mlx5_txpp_destroy(sh);
+	ret = pthread_mutex_unlock(&sh->txpp.mutex);
+	MLX5_ASSERT(!ret);
+	RTE_SET_USED(ret);
+}
-- 
1.8.3.1