-----Original Message-----
From: Richardson, Bruce <redacted>
Sent: Wednesday, June 16, 2021 16:05
To: Wang, Haiyue <redacted>
Cc: Chengwen Feng <redacted>; thomas@monjalon.net; Yigit, Ferruh
[off-list ref]; dev@dpdk.org; nipun.gupta@nxp.com; hemant.agrawal@nxp.com;
maxime.coquelin@redhat.com; honnappa.nagarahalli@arm.com; jerinj@marvell.com;
david.marchand@redhat.com; jerinjacobk@gmail.com; Xia, Chenbo [off-list ref]
Subject: Re: [dpdk-dev] [RFC PATCH] dmadev: introduce DMA device library

On Wed, Jun 16, 2021 at 03:17:51AM +0100, Wang, Haiyue wrote:

quoted

quoted

-----Original Message-----
From: dev <redacted> On Behalf Of Chengwen Feng
Sent: Tuesday, June 15, 2021 21:22
To: thomas@monjalon.net; Yigit, Ferruh <redacted>
Cc: dev@dpdk.org; nipun.gupta@nxp.com; hemant.agrawal@nxp.com; maxime.coquelin@redhat.com;
honnappa.nagarahalli@arm.com; jerinj@marvell.com; david.marchand@redhat.com; Richardson, Bruce
[off-list ref]; jerinjacobk@gmail.com
Subject: [dpdk-dev] [RFC PATCH] dmadev: introduce DMA device library

This patch introduces 'dmadevice' which is a generic type of DMA
device.

The APIs of dmadev library exposes some generic operations which can
enable configuration and I/O with the DMA devices.

Signed-off-by: Chengwen Feng <redacted>
---
 lib/dmadev/rte_dmadev.h     | 531 ++++++++++++++++++++++++++++++++++++++++++++
 lib/dmadev/rte_dmadev_pmd.h | 384 ++++++++++++++++++++++++++++++++
 2 files changed, 915 insertions(+)
 create mode 100644 lib/dmadev/rte_dmadev.h
 create mode 100644 lib/dmadev/rte_dmadev_pmd.h

diff --git a/lib/dmadev/rte_dmadev.h b/lib/dmadev/rte_dmadev.h
new file mode 100644
index 0000000..ca7c8a8
--- /dev/null
+++ b/lib/dmadev/rte_dmadev.h

@@ -0,0 +1,531 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2021 HiSilicon Limited.
+ */
+
+#ifndef _RTE_DMADEV_H_
+#define _RTE_DMADEV_H_
+
+/**
+ * @file rte_dmadev.h
+ *
+ * DMA (Direct Memory Access) device APIs.
+ *
+ * Defines RTE DMA Device APIs for DMA operations and its provisioning.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rte_common.h>
+#include <rte_memory.h>
+#include <rte_errno.h>
+#include <rte_compat.h>
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Get the total number of DMA devices that have been successfully
+ * initialised.
+ *
+ * @return
+ *   The total number of usable DMA devices.
+ */
+__rte_experimental
+uint16_t
+rte_dmadev_count(void);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Get the device identifier for the named DMA device.
+ *
+ * @param name
+ *   DMA device name to select the DMA device identifier.
+ *
+ * @return
+ *   Returns DMA device identifier on success.
+ *   - <0: Failure to find named DMA device.
+ */
+__rte_experimental
+int
+rte_dmadev_get_dev_id(const char *name);
+

Like 'struct rte_pci_device', 'struct rte_vdev_device', and new introduced
'struct rte_auxiliary_device', have the "rte_xxx_device" name style,
How about 'struct rte_dma_device' name ?

One difference is that the pci, vdev and auxiliary devices are all devices
types on a bus, rather than devices in a functional class like ethdev,
rawdev, eventdev. I think what is here is fine for now - if you feel

From this point of view, yes, it's fine. Thanks, Bruce.

strongly we can revisit later.