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numam-dpdk/doc/guides/nics/dpaa.rst
Ferruh Yigit 1bb4a528c4 ethdev: fix max Rx packet length 
There is a confusion on setting max Rx packet length, this patch aims to
clarify it.

'rte_eth_dev_configure()' API accepts max Rx packet size via
'uint32_t max_rx_pkt_len' field of the config struct 'struct
rte_eth_conf'.

Also 'rte_eth_dev_set_mtu()' API can be used to set the MTU, and result
stored into '(struct rte_eth_dev)->data->mtu'.

These two APIs are related but they work in a disconnected way, they
store the set values in different variables which makes hard to figure
out which one to use, also having two different method for a related
functionality is confusing for the users.

Other issues causing confusion is:
* maximum transmission unit (MTU) is payload of the Ethernet frame. And
  'max_rx_pkt_len' is the size of the Ethernet frame. Difference is
  Ethernet frame overhead, and this overhead may be different from
  device to device based on what device supports, like VLAN and QinQ.
* 'max_rx_pkt_len' is only valid when application requested jumbo frame,
  which adds additional confusion and some APIs and PMDs already
  discards this documented behavior.
* For the jumbo frame enabled case, 'max_rx_pkt_len' is an mandatory
  field, this adds configuration complexity for application.

As solution, both APIs gets MTU as parameter, and both saves the result
in same variable '(struct rte_eth_dev)->data->mtu'. For this
'max_rx_pkt_len' updated as 'mtu', and it is always valid independent
from jumbo frame.

For 'rte_eth_dev_configure()', 'dev->data->dev_conf.rxmode.mtu' is user
request and it should be used only within configure function and result
should be stored to '(struct rte_eth_dev)->data->mtu'. After that point
both application and PMD uses MTU from this variable.

When application doesn't provide an MTU during 'rte_eth_dev_configure()'
default 'RTE_ETHER_MTU' value is used.

Additional clarification done on scattered Rx configuration, in
relation to MTU and Rx buffer size.
MTU is used to configure the device for physical Rx/Tx size limitation,
Rx buffer is where to store Rx packets, many PMDs use mbuf data buffer
size as Rx buffer size.
PMDs compare MTU against Rx buffer size to decide enabling scattered Rx
or not. If scattered Rx is not supported by device, MTU bigger than Rx
buffer size should fail.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Acked-by: Somnath Kotur <somnath.kotur@broadcom.com>
Acked-by: Huisong Li <lihuisong@huawei.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: Rosen Xu <rosen.xu@intel.com>
Acked-by: Hyong Youb Kim <hyonkim@cisco.com>
2021-10-18 19:20:20 +02:00

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.. SPDX-License-Identifier: BSD-3-Clause
Copyright 2017,2020 NXP
DPAA Poll Mode Driver
=====================
The DPAA NIC PMD (**librte_net_dpaa**) provides poll mode driver
support for the inbuilt NIC found in the **NXP DPAA** SoC family.
More information can be found at `NXP Official Website
<http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/qoriq-arm-processors:QORIQ-ARM>`_.
NXP DPAA (Data Path Acceleration Architecture - Gen 1)
------------------------------------------------------
This section provides an overview of the NXP DPAA architecture
and how it is integrated into the DPDK.
Contents summary
- DPAA overview
- DPAA driver architecture overview
- FMAN configuration tools and library
.. _dpaa_overview:
DPAA Overview
~~~~~~~~~~~~~
Reference: `FSL DPAA Architecture <http://www.nxp.com/assets/documents/data/en/white-papers/QORIQDPAAWP.pdf>`_.
The QorIQ Data Path Acceleration Architecture (DPAA) is a set of hardware
components on specific QorIQ series multicore processors. This architecture
provides the infrastructure to support simplified sharing of networking
interfaces and accelerators by multiple CPU cores, and the accelerators
themselves.
DPAA includes:
- Cores
- Network and packet I/O
- Hardware offload accelerators
- Infrastructure required to facilitate flow of packets between the components above
Infrastructure components are:
- The Queue Manager (QMan) is a hardware accelerator that manages frame queues.
It allows CPUs and other accelerators connected to the SoC datapath to
enqueue and dequeue ethernet frames, thus providing the infrastructure for
data exchange among CPUs and datapath accelerators.
- The Buffer Manager (BMan) is a hardware buffer pool management block that
allows software and accelerators on the datapath to acquire and release
buffers in order to build frames.
Hardware accelerators are:
- SEC - Cryptographic accelerator
- PME - Pattern matching engine
The Network and packet I/O component:
- The Frame Manager (FMan) is a key component in the DPAA and makes use of the
DPAA infrastructure (QMan and BMan). FMan is responsible for packet
distribution and policing. Each frame can be parsed, classified and results
may be attached to the frame. This meta data can be used to select
particular QMan queue, which the packet is forwarded to.
DPAA DPDK - Poll Mode Driver Overview
-------------------------------------
This section provides an overview of the drivers for DPAA:
* Bus driver and associated "DPAA infrastructure" drivers
* Functional object drivers (such as Ethernet).
Brief description of each driver is provided in layout below as well as
in the following sections.
.. code-block:: console
+------------+
| DPDK DPAA |
| PMD |
+-----+------+
|
+-----+------+ +---------------+
: Ethernet :.......| DPDK DPAA |
. . . . . . . . . : (FMAN) : | Mempool driver|
. +---+---+----+ | (BMAN) |
. ^ | +-----+---------+
. | |<enqueue, .
. | | dequeue> .
. | | .
. +---+---V----+ .
. . . . . . . . . . .: Portal drv : .
. . : : .
. . +-----+------+ .
. . : QMAN : .
. . : Driver : .
+----+------+-------+ +-----+------+ .
| DPDK DPAA Bus | | .
| driver |....................|.....................
| /bus/dpaa | |
+-------------------+ |
|
========================== HARDWARE =====|========================
PHY
=========================================|========================
In the above representation, solid lines represent components which interface
with DPDK RTE Framework and dotted lines represent DPAA internal components.
DPAA Bus driver
~~~~~~~~~~~~~~~
The DPAA bus driver is a ``rte_bus`` driver which scans the platform like bus.
Key functions include:
- Scanning and parsing the various objects and adding them to their respective
device list.
- Performing probe for available drivers against each scanned device
- Creating necessary ethernet instance before passing control to the PMD
DPAA NIC Driver (PMD)
~~~~~~~~~~~~~~~~~~~~~
DPAA PMD is traditional DPDK PMD which provides necessary interface between
RTE framework and DPAA internal components/drivers.
- Once devices have been identified by DPAA Bus, each device is associated
with the PMD
- PMD is responsible for implementing necessary glue layer between RTE APIs
and lower level QMan and FMan blocks.
The Ethernet driver is bound to a FMAN port and implements the interfaces
needed to connect the DPAA network interface to the network stack.
Each FMAN Port corresponds to a DPDK network interface.
Features
^^^^^^^^
Features of the DPAA PMD are:
- Multiple queues for TX and RX
- Receive Side Scaling (RSS)
- Packet type information
- Checksum offload
- Promiscuous mode
DPAA Mempool Driver
~~~~~~~~~~~~~~~~~~~
DPAA has a hardware offloaded buffer pool manager, called BMan, or Buffer
Manager.
- Using standard Mempools operations RTE API, the mempool driver interfaces
with RTE to service each mempool creation, deletion, buffer allocation and
deallocation requests.
- Each FMAN instance has a BMan pool attached to it during initialization.
Each Tx frame can be automatically released by hardware, if allocated from
this pool.
Allowing & Blocking
-------------------
For blocking a DPAA device, following commands can be used.
.. code-block:: console
<dpdk app> <EAL args> -b "dpaa_bus:fmX-macY" -- ...
e.g. "dpaa_bus:fm1-mac4"
Supported DPAA SoCs
-------------------
- LS1043A/LS1023A
- LS1046A/LS1026A
Prerequisites
-------------
See :doc:`../platform/dpaa` for setup information
- Follow the DPDK :ref:`Getting Started Guide for Linux <linux_gsg>`
to setup the basic DPDK environment.
.. note::
Some part of dpaa bus code (qbman and fman - library) routines are
dual licensed (BSD & GPLv2), however they are used as BSD in DPDK in userspace.
Pre-Installation Configuration
------------------------------
Environment Variables
~~~~~~~~~~~~~~~~~~~~~
DPAA drivers uses the following environment variables to configure its
state during application initialization:
- ``DPAA_NUM_RX_QUEUES`` (default 1)
This defines the number of Rx queues configured for an application, per
port. Hardware would distribute across these many number of queues on Rx
of packets.
In case the application is configured to use lesser number of queues than
configured above, it might result in packet loss (because of distribution).
- ``DPAA_PUSH_QUEUES_NUMBER`` (default 4)
This defines the number of High performance queues to be used for ethdev Rx.
These queues use one private HW portal per queue configured, so they are
limited in the system. The first configured ethdev queues will be
automatically be assigned from the these high perf PUSH queues. Any queue
configuration beyond that will be standard Rx queues. The application can
choose to change their number if HW portals are limited.
The valid values are from '0' to '4'. The values shall be set to '0' if the
application want to use eventdev with DPAA device.
Currently these queues are not used for LS1023/LS1043 platform by default.
Driver compilation and testing
------------------------------
Refer to the document :ref:`compiling and testing a PMD for a NIC <pmd_build_and_test>`
for details.
#. Running testpmd:
Follow instructions available in the document
:ref:`compiling and testing a PMD for a NIC <pmd_build_and_test>`
to run testpmd.
Example output:
.. code-block:: console
./<build_dir>/app/dpdk-testpmd -c 0xff -n 1 \
-- -i --portmask=0x3 --nb-cores=1 --no-flush-rx
.....
EAL: Registered [pci] bus.
EAL: Registered [dpaa] bus.
EAL: Detected 4 lcore(s)
.....
EAL: dpaa: Bus scan completed
.....
Configuring Port 0 (socket 0)
Port 0: 00:00:00:00:00:01
Configuring Port 1 (socket 0)
Port 1: 00:00:00:00:00:02
.....
Checking link statuses...
Port 0 Link Up - speed 10000 Mbps - full-duplex
Port 1 Link Up - speed 10000 Mbps - full-duplex
Done
testpmd>
FMAN Config
-----------
Frame Manager is also responsible for parser, classify and distribute
functionality in the DPAA.
FMAN supports:
Packet parsing at wire speed. It supports standard protocols parsing and
identification by HW (VLAN/IP/UDP/TCP/SCTP/PPPoE/PPP/MPLS/GRE/IPSec).
It supports non-standard UDF header parsing for custom protocols.
Classification / Distribution: Coarse classification based on Key generation
Hash and exact match lookup
FMC - FMAN Configuration Tool
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This tool is available in User Space. The tool is used to configure FMAN
Physical (MAC) or Ephemeral (OH)ports for Parse/Classify/distribute.
The PCDs can be hash based where a set of fields are key input for hash
generation within FMAN keygen. The hash value is used to generate a FQID for
frame. There is a provision to setup exact match lookup too where field
values within a packet drives corresponding FQID.
Currently it works on XML file inputs.
Limitations:
1.For Dynamic Configuration change, currently no support is available.
E.g. enable/disable a port, a operator (set of VLANs and associate rules).
2.During FMC configuration, port for which policy is being configured is
brought down and the policy is flushed on port before new policy is updated
for the port. Support is required to add/append/delete etc.
3.FMC, being a separate user-space application, needs to be invoked from
Shell.
The details can be found in FMC Doc at:
`Frame Manager Configuration Tool <https://www.nxp.com/docs/en/application-note/AN4760.pdf>`_.
FMLIB
~~~~~
The Frame Manager library provides an API on top of the Frame Manager driver
ioctl calls, that provides a user space application with a simple way to
configure driver parameters and PCD (parse - classify - distribute) rules.
This is an alternate to the FMC based configuration. This library provides
direct ioctl based interfaces for FMAN configuration as used by the FMC tool
as well. This helps in overcoming the main limitation of FMC - i.e. lack
of dynamic configuration.
The location for the fmd driver as used by FMLIB and FMC is as follows:
`Kernel FMD Driver
<https://source.codeaurora.org/external/qoriq/qoriq-components/linux/tree/drivers/net/ethernet/freescale/sdk_fman?h=linux-4.19-rt>`_.
VSP (Virtual Storage Profile)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The storage profiled are means to provide virtualized interface. A ranges of
storage profiles cab be associated to Ethernet ports.
They are selected during classification. Specify how the frame should be
written to memory and which buffer pool to select for packet storage in
queues. Start and End margin of buffer can also be configured.
Limitations
-----------
Platform Requirement
~~~~~~~~~~~~~~~~~~~~
DPAA drivers for DPDK can only work on NXP SoCs as listed in the
``Supported DPAA SoCs``.
Maximum packet length
~~~~~~~~~~~~~~~~~~~~~
The DPAA SoC family support a maximum of a 10240 jumbo frame. The value
is fixed and cannot be changed. So, even when the ``rxmode.mtu``
member of ``struct rte_eth_conf`` is set to a value lower than 10240, frames
up to 10240 bytes can still reach the host interface.
Multiprocess Support
~~~~~~~~~~~~~~~~~~~~
Current version of DPAA driver doesn't support multi-process applications
where I/O is performed using secondary processes. This feature would be
implemented in subsequent versions.
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