[dpdk-dev] [PATCH v16 6/9] dma/skeleton: introduce skeleton dmadev driver

[Chengwen Feng <fengchengwen@huawei.com>]

Skeleton dmadevice driver, on the lines of rawdev skeleton, is for
showcasing of the dmadev library. This driver implements cpucopy 'DMA',
so that a test module can be developed.

Design of skeleton involves a virtual device which is plugged into VDEV
bus on initialization.

Also, enable compilation of dmadev skeleton drivers.

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
---
 drivers/dma/meson.build                |  11 +
 drivers/dma/skeleton/meson.build       |   7 +
 drivers/dma/skeleton/skeleton_dmadev.c | 595 +++++++++++++++++++++++++++++++++
 drivers/dma/skeleton/skeleton_dmadev.h |  75 +++++
 drivers/dma/skeleton/version.map       |   3 +
 drivers/meson.build                    |   1 +
 6 files changed, 692 insertions(+)
 create mode 100644 drivers/dma/meson.build
 create mode 100644 drivers/dma/skeleton/meson.build
 create mode 100644 drivers/dma/skeleton/skeleton_dmadev.c
 create mode 100644 drivers/dma/skeleton/skeleton_dmadev.h
 create mode 100644 drivers/dma/skeleton/version.map

diff --git a/drivers/dma/meson.build b/drivers/dma/meson.build
new file mode 100644
index 0000000..0c2c34c
--- /dev/null
+++ b/drivers/dma/meson.build
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2021 HiSilicon Limited.
+
+if is_windows
+    subdir_done()
+endif
+
+drivers = [
+        'skeleton',
+]
+std_deps = ['dmadev']
diff --git a/drivers/dma/skeleton/meson.build b/drivers/dma/skeleton/meson.build
new file mode 100644
index 0000000..27509b1
--- /dev/null
+++ b/drivers/dma/skeleton/meson.build
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2021 HiSilicon Limited.
+
+deps += ['dmadev', 'kvargs', 'ring', 'bus_vdev']
+sources = files(
+        'skeleton_dmadev.c',
+)
diff --git a/drivers/dma/skeleton/skeleton_dmadev.c b/drivers/dma/skeleton/skeleton_dmadev.c
new file mode 100644
index 0000000..b3ab4a0
--- /dev/null
+++ b/drivers/dma/skeleton/skeleton_dmadev.c
@@ -0,0 +1,595 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 HiSilicon Limited.
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <rte_bus_vdev.h>
+#include <rte_common.h>
+#include <rte_cycles.h>
+#include <rte_debug.h>
+#include <rte_dev.h>
+#include <rte_eal.h>
+#include <rte_kvargs.h>
+#include <rte_lcore.h>
+#include <rte_log.h>
+#include <rte_malloc.h>
+#include <rte_memory.h>
+#include <rte_memcpy.h>
+#include <rte_ring.h>
+
+#include <rte_dmadev_pmd.h>
+
+#include "skeleton_dmadev.h"
+
+/* Count of instances */
+static uint16_t skeldma_init_once;
+
+static int
+skeldma_info_get(const struct rte_dmadev *dev, struct rte_dmadev_info *dev_info,
+		 uint32_t info_sz)
+{
+#define SKELDMA_MAX_DESC	8192
+#define SKELDMA_MIN_DESC	128
+
+	RTE_SET_USED(dev);
+	RTE_SET_USED(info_sz);
+
+	dev_info->dev_capa = RTE_DMADEV_CAPA_MEM_TO_MEM |
+			     RTE_DMADEV_CAPA_SVA |
+			     RTE_DMADEV_CAPA_OPS_COPY;
+	dev_info->max_vchans = 1;
+	dev_info->max_desc = SKELDMA_MAX_DESC;
+	dev_info->min_desc = SKELDMA_MIN_DESC;
+
+	return 0;
+}
+
+static int
+skeldma_configure(struct rte_dmadev *dev, const struct rte_dmadev_conf *conf)
+{
+	RTE_SET_USED(dev);
+	RTE_SET_USED(conf);
+	return 0;
+}
+
+static void *
+cpucopy_thread(void *param)
+{
+#define SLEEP_THRESHOLD		10000
+#define SLEEP_US_VAL		10
+
+	struct rte_dmadev *dev = (struct rte_dmadev *)param;
+	struct skeldma_hw *hw = dev->dev_private;
+	struct skeldma_desc *desc = NULL;
+	int ret;
+
+	while (!hw->exit_flag) {
+		ret = rte_ring_dequeue(hw->desc_running, (void **)&desc);
+		if (ret) {
+			hw->zero_req_count++;
+			if (hw->zero_req_count > SLEEP_THRESHOLD) {
+				if (hw->zero_req_count == 0)
+					hw->zero_req_count = SLEEP_THRESHOLD;
+				rte_delay_us_sleep(SLEEP_US_VAL);
+			}
+			continue;
+		}
+
+		hw->zero_req_count = 0;
+		rte_memcpy(desc->dst, desc->src, desc->len);
+		hw->completed_count++;
+		(void)rte_ring_enqueue(hw->desc_completed, (void *)desc);
+	}
+
+	return NULL;
+}
+
+static void
+fflush_ring(struct skeldma_hw *hw, struct rte_ring *ring)
+{
+	struct skeldma_desc *desc = NULL;
+	while (rte_ring_count(ring) > 0) {
+		(void)rte_ring_dequeue(ring, (void **)&desc);
+		(void)rte_ring_enqueue(hw->desc_empty, (void *)desc);
+	}
+}
+
+static int
+skeldma_start(struct rte_dmadev *dev)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+	rte_cpuset_t cpuset;
+	int ret;
+
+	if (hw->desc_mem == NULL) {
+		SKELDMA_ERR("Vchan was not setup, start fail!\n");
+		return -EINVAL;
+	}
+
+	/* Reset the dmadev to a known state, include:
+	 * 1) fflush pending/running/completed ring to empty ring.
+	 * 2) init ring idx to zero.
+	 * 3) init running statistics.
+	 * 4) mark cpucopy task exit_flag to false.
+	 */
+	fflush_ring(hw, hw->desc_pending);
+	fflush_ring(hw, hw->desc_running);
+	fflush_ring(hw, hw->desc_completed);
+	hw->ridx = 0;
+	hw->submitted_count = 0;
+	hw->zero_req_count = 0;
+	hw->completed_count = 0;
+	hw->exit_flag = false;
+
+	rte_mb();
+
+	ret = rte_ctrl_thread_create(&hw->thread, "dma_skeleton", NULL,
+				     cpucopy_thread, dev);
+	if (ret) {
+		SKELDMA_ERR("Start cpucopy thread fail!\n");
+		return -EINVAL;
+	}
+
+	if (hw->lcore_id != -1) {
+		cpuset = rte_lcore_cpuset(hw->lcore_id);
+		ret = pthread_setaffinity_np(hw->thread, sizeof(cpuset),
+					     &cpuset);
+		if (ret)
+			SKELDMA_WARN("Set thread affinity lcore = %u fail!\n",
+				     hw->lcore_id);
+	}
+
+	return 0;
+}
+
+static int
+skeldma_stop(struct rte_dmadev *dev)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+
+	hw->exit_flag = true;
+	rte_delay_ms(1);
+
+	pthread_cancel(hw->thread);
+	pthread_join(hw->thread, NULL);
+
+	return 0;
+}
+
+static int
+vchan_setup(struct skeldma_hw *hw, uint16_t nb_desc)
+{
+	struct skeldma_desc *desc;
+	struct rte_ring *empty;
+	struct rte_ring *pending;
+	struct rte_ring *running;
+	struct rte_ring *completed;
+	uint16_t i;
+
+	desc = rte_zmalloc_socket("dma_skelteon_desc",
+				  nb_desc * sizeof(struct skeldma_desc),
+				  RTE_CACHE_LINE_SIZE, hw->socket_id);
+	if (desc == NULL) {
+		SKELDMA_ERR("Malloc dma skeleton desc fail!\n");
+		return -ENOMEM;
+	}
+
+	empty = rte_ring_create("dma_skeleton_desc_empty", nb_desc,
+				hw->socket_id, RING_F_SP_ENQ | RING_F_SC_DEQ);
+	pending = rte_ring_create("dma_skeleton_desc_pending", nb_desc,
+				  hw->socket_id, RING_F_SP_ENQ | RING_F_SC_DEQ);
+	running = rte_ring_create("dma_skeleton_desc_running", nb_desc,
+				  hw->socket_id, RING_F_SP_ENQ | RING_F_SC_DEQ);
+	completed = rte_ring_create("dma_skeleton_desc_completed", nb_desc,
+				  hw->socket_id, RING_F_SP_ENQ | RING_F_SC_DEQ);
+	if (empty == NULL || pending == NULL || running == NULL ||
+	    completed == NULL) {
+		SKELDMA_ERR("Create dma skeleton desc ring fail!\n");
+		rte_ring_free(empty);
+		rte_ring_free(pending);
+		rte_ring_free(running);
+		rte_ring_free(completed);
+		rte_free(desc);
+		return -ENOMEM;
+	}
+
+	/* The real usable ring size is *count-1* instead of *count* to
+	 * differentiate a free ring from an empty ring.
+	 * @see rte_ring_create
+	 */
+	for (i = 0; i < nb_desc - 1; i++)
+		(void)rte_ring_enqueue(empty, (void *)(desc + i));
+
+	hw->desc_mem = desc;
+	hw->desc_empty = empty;
+	hw->desc_pending = pending;
+	hw->desc_running = running;
+	hw->desc_completed = completed;
+
+	return 0;
+}
+
+static void
+vchan_release(struct skeldma_hw *hw)
+{
+	if (hw->desc_mem == NULL)
+		return;
+
+	rte_free(hw->desc_mem);
+	hw->desc_mem = NULL;
+	rte_ring_free(hw->desc_empty);
+	hw->desc_empty = NULL;
+	rte_ring_free(hw->desc_pending);
+	hw->desc_pending = NULL;
+	rte_ring_free(hw->desc_running);
+	hw->desc_running = NULL;
+	rte_ring_free(hw->desc_completed);
+	hw->desc_completed = NULL;
+}
+
+static int
+skeldma_close(struct rte_dmadev *dev)
+{
+	/* The device already stopped */
+	vchan_release(dev->dev_private);
+	return 0;
+}
+
+static int
+skeldma_vchan_setup(struct rte_dmadev *dev, uint16_t vchan,
+		    const struct rte_dmadev_vchan_conf *conf)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+
+	RTE_SET_USED(vchan);
+
+	if (!rte_is_power_of_2(conf->nb_desc)) {
+		SKELDMA_ERR("Number of desc must be power of 2!\n");
+		return -EINVAL;
+	}
+
+	vchan_release(hw);
+	return vchan_setup(hw, conf->nb_desc);
+}
+
+static int
+skeldma_stats_get(const struct rte_dmadev *dev, uint16_t vchan,
+		  struct rte_dmadev_stats *stats, uint32_t stats_sz)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+
+	RTE_SET_USED(vchan);
+	RTE_SET_USED(stats_sz);
+
+	stats->submitted = hw->submitted_count;
+	stats->completed = hw->completed_count;
+	stats->errors = 0;
+
+	return 0;
+}
+
+static int
+skeldma_stats_reset(struct rte_dmadev *dev, uint16_t vchan)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+
+	RTE_SET_USED(vchan);
+
+	hw->submitted_count = 0;
+	hw->completed_count = 0;
+
+	return 0;
+}
+
+static int
+skeldma_dump(const struct rte_dmadev *dev, FILE *f)
+{
+#define GET_RING_COUNT(ring)	((ring) ? (rte_ring_count(ring)) : 0)
+
+	struct skeldma_hw *hw = dev->dev_private;
+
+	fprintf(f,
+		"  lcore_id: %d\n"
+		"  socket_id: %d\n"
+		"  desc_empty_ring_count: %u\n"
+		"  desc_pending_ring_count: %u\n"
+		"  desc_running_ring_count: %u\n"
+		"  desc_completed_ring_count: %u\n",
+		hw->lcore_id, hw->socket_id,
+		GET_RING_COUNT(hw->desc_empty),
+		GET_RING_COUNT(hw->desc_pending),
+		GET_RING_COUNT(hw->desc_running),
+		GET_RING_COUNT(hw->desc_completed));
+	fprintf(f,
+		"  next_ring_idx: %u\n"
+		"  submitted_count: %" PRIu64 "\n"
+		"  completed_count: %" PRIu64 "\n",
+		hw->ridx, hw->submitted_count, hw->completed_count);
+
+	return 0;
+}
+
+static void
+submit(struct skeldma_hw *hw, struct skeldma_desc *desc)
+{
+	uint16_t count = rte_ring_count(hw->desc_pending);
+	struct skeldma_desc *pend_desc = NULL;
+
+	while (count > 0) {
+		(void)rte_ring_dequeue(hw->desc_pending, (void **)&pend_desc);
+		(void)rte_ring_enqueue(hw->desc_running, (void *)pend_desc);
+		count--;
+	}
+
+	if (desc)
+		(void)rte_ring_enqueue(hw->desc_running, (void *)desc);
+}
+
+static int
+skeldma_copy(struct rte_dmadev *dev, uint16_t vchan,
+	     rte_iova_t src, rte_iova_t dst,
+	     uint32_t length, uint64_t flags)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+	struct skeldma_desc *desc;
+	int ret;
+
+	RTE_SET_USED(vchan);
+	RTE_SET_USED(flags);
+
+	ret = rte_ring_dequeue(hw->desc_empty, (void **)&desc);
+	if (ret)
+		return -ENOSPC;
+	desc->src = (void *)src;
+	desc->dst = (void *)dst;
+	desc->len = length;
+	desc->ridx = hw->ridx++;
+	if (flags & RTE_DMA_OP_FLAG_SUBMIT)
+		submit(hw, desc);
+	else
+		(void)rte_ring_enqueue(hw->desc_pending, (void *)desc);
+	hw->submitted_count++;
+
+	return 0;
+}
+
+static int
+skeldma_submit(struct rte_dmadev *dev, uint16_t vchan)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+	RTE_SET_USED(vchan);
+	submit(hw, NULL);
+	return 0;
+}
+
+static uint16_t
+skeldma_completed(struct rte_dmadev *dev,
+		  uint16_t vchan, const uint16_t nb_cpls,
+		  uint16_t *last_idx, bool *has_error)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+	struct skeldma_desc *desc = NULL;
+	uint16_t index = 0;
+	uint16_t count;
+
+	RTE_SET_USED(vchan);
+	RTE_SET_USED(has_error);
+
+	count = RTE_MIN(nb_cpls, rte_ring_count(hw->desc_completed));
+	while (index < count) {
+		(void)rte_ring_dequeue(hw->desc_completed, (void **)&desc);
+		if (index == count - 1)
+			*last_idx = desc->ridx;
+		index++;
+		(void)rte_ring_enqueue(hw->desc_empty, (void *)desc);
+	}
+
+	return count;
+}
+
+static uint16_t
+skeldma_completed_status(struct rte_dmadev *dev,
+			 uint16_t vchan, const uint16_t nb_cpls,
+			 uint16_t *last_idx, enum rte_dma_status_code *status)
+{
+	struct skeldma_hw *hw = dev->dev_private;
+	struct skeldma_desc *desc = NULL;
+	uint16_t index = 0;
+	uint16_t count;
+
+	RTE_SET_USED(vchan);
+
+	count = RTE_MIN(nb_cpls, rte_ring_count(hw->desc_completed));
+	while (index < count) {
+		(void)rte_ring_dequeue(hw->desc_completed, (void **)&desc);
+		if (index == count - 1)
+			*last_idx = desc->ridx;
+		status[index++] = RTE_DMA_STATUS_SUCCESSFUL;
+		(void)rte_ring_enqueue(hw->desc_empty, (void *)desc);
+	}
+
+	return count;
+}
+
+static const struct rte_dmadev_ops skeldma_ops = {
+	.dev_info_get = skeldma_info_get,
+	.dev_configure = skeldma_configure,
+	.dev_start = skeldma_start,
+	.dev_stop = skeldma_stop,
+	.dev_close = skeldma_close,
+
+	.vchan_setup = skeldma_vchan_setup,
+
+	.stats_get = skeldma_stats_get,
+	.stats_reset = skeldma_stats_reset,
+
+	.dev_dump = skeldma_dump,
+};
+
+static int
+skeldma_create(const char *name, struct rte_vdev_device *vdev, int lcore_id)
+{
+	struct rte_dmadev *dev;
+	struct skeldma_hw *hw;
+	int socket_id;
+
+	dev = rte_dmadev_pmd_allocate(name);
+	if (dev == NULL) {
+		SKELDMA_ERR("Unable to allocate dmadev: %s\n", name);
+		return -EINVAL;
+	}
+
+	socket_id = (lcore_id < 0) ? rte_socket_id() :
+				     rte_lcore_to_socket_id(lcore_id);
+	dev->dev_private = rte_zmalloc_socket("dmadev private",
+					      sizeof(struct skeldma_hw),
+					      RTE_CACHE_LINE_SIZE,
+					      socket_id);
+	if (!dev->dev_private) {
+		SKELDMA_ERR("Unable to allocate device private memory\n");
+		(void)rte_dmadev_pmd_release(dev);
+		return -ENOMEM;
+	}
+
+	dev->copy = skeldma_copy;
+	dev->submit = skeldma_submit;
+	dev->completed = skeldma_completed;
+	dev->completed_status = skeldma_completed_status;
+	dev->dev_ops = &skeldma_ops;
+	dev->device = &vdev->device;
+
+	hw = dev->dev_private;
+	hw->lcore_id = lcore_id;
+	hw->socket_id = socket_id;
+
+	return dev->data->dev_id;
+}
+
+static int
+skeldma_destroy(const char *name)
+{
+	struct rte_dmadev *dev;
+	int ret;
+
+	dev = rte_dmadev_get_device_by_name(name);
+	if (!dev)
+		return -EINVAL;
+
+	ret = rte_dmadev_close(dev->data->dev_id);
+	if (ret)
+		return ret;
+
+	rte_free(dev->dev_private);
+	dev->dev_private = NULL;
+	(void)rte_dmadev_pmd_release(dev);
+
+	return 0;
+}
+
+static int
+skeldma_parse_lcore(const char *key __rte_unused,
+		    const char *value,
+		    void *opaque)
+{
+	int lcore_id = atoi(value);
+	if (lcore_id >= 0 && lcore_id < RTE_MAX_LCORE)
+		*(int *)opaque = lcore_id;
+	return 0;
+}
+
+static void
+skeldma_parse_vdev_args(struct rte_vdev_device *vdev, int *lcore_id)
+{
+	static const char *const args[] = {
+		SKELDMA_ARG_LCORE,
+		NULL
+	};
+
+	struct rte_kvargs *kvlist;
+	const char *params;
+
+	params = rte_vdev_device_args(vdev);
+	if (params == NULL || params[0] == '\0')
+		return;
+
+	kvlist = rte_kvargs_parse(params, args);
+	if (!kvlist)
+		return;
+
+	(void)rte_kvargs_process(kvlist, SKELDMA_ARG_LCORE,
+				 skeldma_parse_lcore, lcore_id);
+
+	SKELDMA_INFO("Parse lcore_id = %d\n", *lcore_id);
+
+	rte_kvargs_free(kvlist);
+}
+
+static int
+skeldma_probe(struct rte_vdev_device *vdev)
+{
+	const char *name;
+	int lcore_id = -1;
+	int ret;
+
+	name = rte_vdev_device_name(vdev);
+	if (name == NULL)
+		return -EINVAL;
+
+	if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
+		SKELDMA_ERR("Multiple process not supported for %s\n", name);
+		return -EINVAL;
+	}
+
+	/* More than one instance is not supported */
+	if (skeldma_init_once) {
+		SKELDMA_ERR("Multiple instance not supported for %s\n", name);
+		return -EINVAL;
+	}
+
+	skeldma_parse_vdev_args(vdev, &lcore_id);
+
+	ret = skeldma_create(name, vdev, lcore_id);
+	if (ret >= 0) {
+		SKELDMA_INFO("Create %s dmadev lcore-id %d\n", name, lcore_id);
+		/* Device instance created; Second instance not possible */
+		skeldma_init_once = 1;
+	}
+
+	return ret < 0 ? ret : 0;
+}
+
+static int
+skeldma_remove(struct rte_vdev_device *vdev)
+{
+	const char *name;
+	int ret;
+
+	name = rte_vdev_device_name(vdev);
+	if (name == NULL)
+		return -1;
+
+	ret = skeldma_destroy(name);
+	if (!ret) {
+		skeldma_init_once = 0;
+		SKELDMA_INFO("Remove %s dmadev\n", name);
+	}
+
+	return ret;
+}
+
+static struct rte_vdev_driver skeldma_pmd_drv = {
+	.probe = skeldma_probe,
+	.remove = skeldma_remove,
+	.drv_flags = RTE_VDEV_DRV_NEED_IOVA_AS_VA,
+};
+
+RTE_LOG_REGISTER_DEFAULT(skeldma_logtype, INFO);
+RTE_PMD_REGISTER_VDEV(dma_skeleton, skeldma_pmd_drv);
+RTE_PMD_REGISTER_PARAM_STRING(dma_skeleton,
+		SKELDMA_ARG_LCORE "=<uint16> ");
diff --git a/drivers/dma/skeleton/skeleton_dmadev.h b/drivers/dma/skeleton/skeleton_dmadev.h
new file mode 100644
index 0000000..6495653
--- /dev/null
+++ b/drivers/dma/skeleton/skeleton_dmadev.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 HiSilicon Limited.
+ */
+
+#ifndef __SKELETON_DMADEV_H__
+#define __SKELETON_DMADEV_H__
+
+#include <rte_dmadev.h>
+
+extern int skeldma_logtype;
+#define SKELDMA_LOG(level, fmt, args...) \
+	rte_log(RTE_LOG_ ## level, skeldma_logtype, "%s(): " fmt "", \
+		__func__, ##args)
+
+#define SKELDMA_DEBUG(fmt, args...) \
+	SKELDMA_LOG(DEBUG, fmt, ## args)
+#define SKELDMA_INFO(fmt, args...) \
+	SKELDMA_LOG(INFO, fmt, ## args)
+#define SKELDMA_WARN(fmt, args...) \
+	SKELDMA_LOG(WARNING, fmt, ## args)
+#define SKELDMA_ERR(fmt, args...) \
+	SKELDMA_LOG(ERR, fmt, ## args)
+
+#define SKELDMA_ARG_LCORE	"lcore"
+
+struct skeldma_desc {
+	void *src;
+	void *dst;
+	uint32_t len;
+	uint16_t ridx; /* ring idx */
+};
+
+struct skeldma_hw {
+	int lcore_id; /* cpucopy task affinity core */
+	int socket_id;
+	pthread_t thread; /* cpucopy task thread */
+	volatile int exit_flag; /* cpucopy task exit flag */
+
+	struct skeldma_desc *desc_mem;
+
+	/* Descriptor ring state machine:
+	 *
+	 *  -----------     enqueue without submit     -----------
+	 *  |  empty  |------------------------------->| pending |
+	 *  -----------\                               -----------
+	 *       ^      \------------                       |
+	 *       |                  |                       |submit doorbell
+	 *       |                  |                       |
+	 *       |                  |enqueue with submit    |
+	 *       |get completed     |------------------|    |
+	 *       |                                     |    |
+	 *       |                                     v    v
+	 *  -----------     cpucopy thread working     -----------
+	 *  |completed|<-------------------------------| running |
+	 *  -----------                                -----------
+	 */
+	struct rte_ring *desc_empty;
+	struct rte_ring *desc_pending;
+	struct rte_ring *desc_running;
+	struct rte_ring *desc_completed;
+
+	/* Cache delimiter for dataplane API's operation data */
+	char cache1 __rte_cache_aligned;
+	uint16_t ridx;  /* ring idx */
+	uint64_t submitted_count;
+
+	/* Cache delimiter for cpucopy thread's operation data */
+	char cache2 __rte_cache_aligned;
+	uint32_t zero_req_count;
+	uint64_t completed_count;
+};
+
+int test_dma_skeleton(uint16_t dev_id);
+
+#endif /* __SKELETON_DMADEV_H__ */
diff --git a/drivers/dma/skeleton/version.map b/drivers/dma/skeleton/version.map
new file mode 100644
index 0000000..c2e0723
--- /dev/null
+++ b/drivers/dma/skeleton/version.map
@@ -0,0 +1,3 @@
+DPDK_22 {
+	local: *;
+};
diff --git a/drivers/meson.build b/drivers/meson.build
index bc6f4f5..383f648 100644
--- a/drivers/meson.build
+++ b/drivers/meson.build
@@ -18,6 +18,7 @@ subdirs = [
         'vdpa',           # depends on common, bus and mempool.
         'event',          # depends on common, bus, mempool and net.
         'baseband',       # depends on common and bus.
+        'dma',            # depends on common and bus.
 ]
 
 if meson.is_cross_build()
-- 
2.8.1