numam-dpdk/doc/guides/rawdevs/octeontx2_dma.rst
Jerin Jacob f5be5d9921 usertools: add octeontx2 DMA device binding
Update the devbind script with new section of DMA devices, also
added OCTEONTX2 DMA device ID to DMA device list

Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: Satha Rao <skoteshwar@marvell.com>
2019-07-05 12:43:54 +02:00

116 lines
3.7 KiB
ReStructuredText

.. SPDX-License-Identifier: BSD-3-Clause
Copyright(c) 2019 Marvell International Ltd.
OCTEON TX2 DMA Driver
=====================
OCTEON TX2 has an internal DMA unit which can be used by applications to initiate
DMA transaction internally, from/to host when OCTEON TX2 operates in PCIe End
Point mode. The DMA PF function supports 8 VFs corresponding to 8 DMA queues.
Each DMA queue was exposed as a VF function when SRIOV enabled.
Features
--------
This DMA PMD supports below 3 modes of memory transfers
#. Internal - OCTEON TX2 DRAM to DRAM without core intervention
#. Inbound - Host DRAM to OCTEON TX2 DRAM without host/OCTEON TX2 cores involvement
#. Outbound - OCTEON TX2 DRAM to Host DRAM without host/OCTEON TX2 cores involvement
Prerequisites and Compilation procedure
---------------------------------------
See :doc:`../platform/octeontx2` for setup information.
Pre-Installation Configuration
------------------------------
Config File Options
~~~~~~~~~~~~~~~~~~~
The following options can be modified in the ``config`` file.
- ``CONFIG_RTE_LIBRTE_PMD_OCTEONTX2_DMA_RAWDEV`` (default ``y``)
Toggle compilation of the ``lrte_pmd_octeontx2_dma`` driver.
Enabling logs
-------------
For enabling logs, use the following EAL parameter:
.. code-block:: console
./your_dma_application <EAL args> --log-level=pmd.raw.octeontx2.dpi,<level>
Using ``pmd.raw.octeontx2.dpi`` as log matching criteria, all Event PMD logs
can be enabled which are lower than logging ``level``.
Initialization
--------------
The number of DMA VFs (queues) enabled can be controlled by setting sysfs
entry, `sriov_numvfs` for the corresponding PF driver.
.. code-block:: console
echo <num_vfs> > /sys/bus/pci/drivers/octeontx2-dpi/0000\:05\:00.0/sriov_numvfs
Once the required VFs are enabled, to be accessible from DPDK, VFs need to be
bound to vfio-pci driver.
Device Setup
-------------
The OCTEON TX2 DPI DMA HW devices will need to be bound to a
user-space IO driver for use. The script ``dpdk-devbind.py`` script
included with DPDK can be used to view the state of the devices and to bind
them to a suitable DPDK-supported kernel driver. When querying the status
of the devices, they will appear under the category of "Misc (rawdev)
devices", i.e. the command ``dpdk-devbind.py --status-dev misc`` can be
used to see the state of those devices alone.
Device Configuration
--------------------
Configuring DMA rawdev device is done using the ``rte_rawdev_configure()``
API, which takes the mempool as parameter. PMD uses this pool to submit DMA
commands to HW.
The following code shows how the device is configured
.. code-block:: c
struct dpi_rawdev_conf_s conf = {0};
struct rte_rawdev_info rdev_info = {.dev_private = &conf};
conf.chunk_pool = (void *)rte_mempool_create_empty(...);
rte_mempool_set_ops_byname(conf.chunk_pool, rte_mbuf_platform_mempool_ops(), NULL);
rte_mempool_populate_default(conf.chunk_pool);
rte_rawdev_configure(dev_id, (rte_rawdev_obj_t)&rdev_info);
Performing Data Transfer
------------------------
To perform data transfer using OCTEON TX2 DMA rawdev devices use standard
``rte_rawdev_enqueue_buffers()`` and ``rte_rawdev_dequeue_buffers()`` APIs.
Self test
---------
On EAL initialization, dma devices will be probed and populated into the
raw devices. The rawdev ID of the device can be obtained using
* Invoke ``rte_rawdev_get_dev_id("DPI:x")`` from the application
where x is the VF device's bus id specified in "bus:device.func" format. Use this
index for further rawdev function calls.
* This PMD supports driver self test, to test DMA internal mode from test
application one can directly calls
``rte_rawdev_selftest(rte_rawdev_get_dev_id("DPI:x"))``