..  SPDX-License-Identifier: BSD-3-Clause
    Copyright(c) 2019-2021 Xilinx, Inc.
    Copyright(c) 2016-2019 Solarflare Communications Inc.

    This software was jointly developed between OKTET Labs (under contract
    for Solarflare) and Solarflare Communications, Inc.

Solarflare libefx-based Poll Mode Driver
========================================

The SFC EFX PMD (**librte_net_sfc_efx**) provides poll mode driver support
for **Solarflare SFN7xxx and SFN8xxx** family of 10/40 Gbps adapters,
**Solarflare XtremeScale X2xxx** family of 10/25/40/50/100 Gbps adapters and
**Alveo SN1000 SmartNICs** family of 10/25/40/50/100 Gbps adapters.
SFC EFX PMD has support for the latest Linux and FreeBSD operating systems.

More information can be found at `Solarflare Communications website
<http://solarflare.com>`_.


Supported NICs
--------------

- Xilinx Adapters:

   - Alveo SN1022 SmartNIC

- Solarflare XtremeScale Adapters:

   - Solarflare X2522 Dual Port SFP28 10/25GbE Adapter

   - Solarflare X2541 Single Port QSFP28 10/25G/100G Adapter

   - Solarflare X2542 Dual Port QSFP28 10/25G/100G Adapter

- Solarflare Flareon [Ultra] Server Adapters:

   - Solarflare SFN8522 Dual Port SFP+ Server Adapter

   - Solarflare SFN8522M Dual Port SFP+ Server Adapter

   - Solarflare SFN8042 Dual Port QSFP+ Server Adapter

   - Solarflare SFN8542 Dual Port QSFP+ Server Adapter

   - Solarflare SFN8722 Dual Port SFP+ OCP Server Adapter

   - Solarflare SFN7002F Dual Port SFP+ Server Adapter

   - Solarflare SFN7004F Quad Port SFP+ Server Adapter

   - Solarflare SFN7042Q Dual Port QSFP+ Server Adapter

   - Solarflare SFN7122F Dual Port SFP+ Server Adapter

   - Solarflare SFN7124F Quad Port SFP+ Server Adapter

   - Solarflare SFN7142Q Dual Port QSFP+ Server Adapter

   - Solarflare SFN7322F Precision Time Synchronization Server Adapter


Features
--------

SFC EFX PMD has support for:

- Multiple transmit and receive queues

- Link state information including link status change interrupt

- IPv4/IPv6 TCP/UDP transmit checksum offload

- Inner IPv4/IPv6 TCP/UDP transmit checksum offload

- Port hardware statistics

- Extended statistics (see Solarflare Server Adapter User's Guide for
  the statistics description)

- Basic flow control

- MTU update

- Jumbo frames up to 9K

- Promiscuous mode

- Allmulticast mode

- TCP segmentation offload (TSO) including VXLAN and GENEVE encapsulated

- Multicast MAC filter

- IPv4/IPv6 TCP/UDP receive checksum offload

- Inner IPv4/IPv6 TCP/UDP receive checksum offload

- Received packet type information

- Receive side scaling (RSS)

- RSS hash

- Scattered Rx DMA for packet that are larger that a single Rx descriptor

- Receive queue interrupts

- Deferred receive and transmit queue start

- Transmit VLAN insertion (if running firmware variant supports it)

- Flow API

- Loopback

- Configurable Rx CRC stripping (if running firmware variant supports it and
  if NIC is configured with single PF per port and without VFs, otherwise
  always stripped)

- SR-IOV PF

- Port representors (see :ref: switch_representation)

- VLAN stripping (if running firmware variant supports it)


Non-supported Features
----------------------

The features not yet supported include:

- Priority-based flow control

- Header split on receive

- VLAN filtering

- LRO


Limitations
-----------

Due to requirements on receive buffer alignment and usage of the receive
buffer for the auxiliary packet information provided by the NIC up to
extra 269 (14 bytes prefix plus up to 255 bytes for end padding) bytes may be
required in the receive buffer.
It should be taken into account when mbuf pool for receive is created.


Equal stride super-buffer mode
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When the receive queue uses equal stride super-buffer DMA mode, one HW Rx
descriptor carries many Rx buffers which contiguously follow each other
with some stride (equal to total size of rte_mbuf as mempool object).
Each Rx buffer is an independent rte_mbuf.
However dedicated mempool manager must be used when mempool for the Rx
queue is created. The manager must support dequeue of the contiguous
block of objects and provide mempool info API to get the block size.

Another limitation of a equal stride super-buffer mode, imposed by the
firmware, is that it allows for a single RSS context.


Tunnels support
---------------

NVGRE, VXLAN and GENEVE tunnels are supported on SFN8xxx and X2xxx family
adapters with full-feature firmware variant running.
**sfboot** should be used to configure NIC to run full-feature firmware variant.
See Solarflare Server Adapter User's Guide for details.

SFN8xxx and X2xxx family adapters provide either inner or outer packet classes.
If adapter firmware advertises support for tunnels then the PMD
configures the hardware to report inner classes, and outer classes are
not reported in received packets.
However, for VXLAN and GENEVE tunnels the PMD does report UDP as the
outer layer 4 packet type.

SFN8xxx and X2xxx family adapters report GENEVE packets as VXLAN.
If UDP ports are configured for only one tunnel type then it is safe to
treat VXLAN packet type indication as the corresponding UDP tunnel type.


Flow API support
----------------

Supported attributes:

- Ingress
- Transfer

Supported pattern items (***non-transfer*** rules):

- VOID

- ETH (exact match of source/destination addresses, individual/group match
  of destination address, EtherType in the outer frame and exact match of
  destination addresses, individual/group match of destination address in
  the inner frame)

- VLAN (exact match of VID, double-tagging is supported)

- IPV4 (exact match of source/destination addresses,
  IP transport protocol)

- IPV6 (exact match of source/destination addresses,
  IP transport protocol)

- TCP (exact match of source/destination ports)

- UDP (exact match of source/destination ports)

- VXLAN (exact match of VXLAN network identifier)

- GENEVE (exact match of virtual network identifier, only Ethernet (0x6558)
  protocol type is supported)

- NVGRE (exact match of virtual subnet ID)

Supported actions (***non-transfer*** rules):

- VOID

- QUEUE

- RSS

- DROP

- FLAG (supported only with ef10_essb Rx datapath)

- MARK (supported only with ef10_essb Rx datapath)

Supported pattern items (***transfer*** rules):

- PORT_REPRESENTOR (cannot repeat; conflicts with other traffic source items)

- REPRESENTED_PORT (cannot repeat; conflicts with other traffic source items)

- PORT_ID (cannot repeat; conflicts with other traffic source items)

- ETH

- VLAN (double-tagging is supported)

- IPV4 (source/destination addresses, IP transport protocol,
  type of service, time to live)

- IPV6 (source/destination addresses, IP transport protocol,
  traffic class, hop limit)

- TCP (source/destination ports, TCP header length + TCP flags)

- UDP (source/destination ports)

- VXLAN (exact match of VXLAN network identifier)

- GENEVE (exact match of virtual network identifier)

- NVGRE (exact match of virtual subnet ID)

Supported actions (***transfer*** rules):

- OF_POP_VLAN

- OF_PUSH_VLAN

- OF_VLAN_SET_VID

- OF_VLAN_SET_PCP

- SET_IPV4_DST

- SET_IPV4_SRC

- SET_MAC_DST

- SET_MAC_SRC

- SET_TP_DST

- SET_TP_SRC

- OF_DEC_NW_TTL

- DEC_TTL

- VXLAN_DECAP

- VXLAN_ENCAP

- FLAG

- MARK

- PF

- VF

- PORT_REPRESENTOR

- REPRESENTED_PORT

- PORT_ID

- COUNT

- INDIRECT

- DROP

Validating flow rules depends on the firmware variant.

The :ref:`flow_isolated_mode` is supported.

The implementation is natively thread-safe.

Ethernet destination individual/group match
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Ethernet item supports I/G matching, if only the corresponding bit is set
in the mask of destination address. If destination address in the spec is
multicast, it matches all multicast (and broadcast) packets, otherwise it
matches unicast packets that are not filtered by other flow rules.

Exceptions to flow rules
~~~~~~~~~~~~~~~~~~~~~~~~

There is a list of exceptional flow rule patterns which will not be
accepted by the PMD. A pattern will be rejected if at least one of the
conditions is met:

- Filtering by IPv4 or IPv6 EtherType without pattern items of internet
  layer and above.

- The last item is IPV4 or IPV6, and it's empty.

- Filtering by TCP or UDP IP transport protocol without pattern items of
  transport layer and above.

- The last item is TCP or UDP, and it's empty.


Prerequisites
-------------

- Requires firmware version:

   - SFN7xxx: **4.7.1.1001** or higher

   - SFN8xxx: **6.0.2.1004** or higher

Visit `Solarflare Support Downloads <https://support.solarflare.com>`_ to get
Solarflare Utilities (either Linux or FreeBSD) with the latest firmware.
Follow instructions from Solarflare Server Adapter User's Guide to
update firmware and configure the adapter.


Configuration
-------------


Compilation Options
~~~~~~~~~~~~~~~~~~~

The following build-time options may be enabled on build time using
``-Dc_args=`` meson argument (e.g.  ``-Dc_args=-DRTE_LIBRTE_SFC_EFX_DEBUG``).

Please note that enabling debugging options may affect system performance.

- ``RTE_LIBRTE_SFC_EFX_DEBUG`` (undefined by default)

  Enable compilation of the extra run-time consistency checks.


Runtime Configuration
~~~~~~~~~~~~~~~~~~~~~

The following per-device parameters can be passed via EAL PCI device
allow option like "-a 02:00.0,arg1=value1,...".

Case-insensitive 1/y/yes/on or 0/n/no/off may be used to specify
boolean parameters value.

- ``class`` [net|vdpa] (default **net**)

  Choose the mode of operation of ef100 device.
  **net** device will work as network device and will be probed by net/sfc driver.
  **vdpa** device will work as vdpa device and will be probed by vdpa/sfc driver.
  If this parameter is not specified then ef100 device will operate as
  network device.

- ``switch_mode`` [legacy|switchdev] (see below for default)

  In legacy mode, NIC firmware provides Ethernet virtual bridging (EVB) API
  to configure switching inside NIC to deliver traffic to physical (PF) and
  virtual (VF) PCI functions. PF driver is responsible to build the
  infrastructure for VFs, and traffic goes to/from VF by default in accordance
  with MAC address assigned, permissions and filters installed by VF drivers.
  In switchdev mode VF traffic goes via port representor (if any) on PF, and
  software virtual switch (for example, Open vSwitch) makes the decision.
  Software virtual switch may install MAE rules to pass established traffic
  flows via hardware and offload software datapath as the result.
  Default is legacy, unless representors are specified, in which case switchdev
  is chosen.

- ``representor`` parameter [list]

  Instantiate port representor Ethernet devices for specified Virtual
  Functions list.

  It is a standard parameter whose format is described in
  :ref:`ethernet_device_standard_device_arguments`.

- ``rx_datapath`` [auto|efx|ef10|ef10_essb] (default **auto**)

  Choose receive datapath implementation.
  **auto** allows the driver itself to make a choice based on firmware
  features available and required by the datapath implementation.
  **efx** chooses libefx-based datapath which supports Rx scatter.
  Supported for SFN7xxx, SFN8xxx and X2xxx family adapters only.
  **ef10** chooses EF10 (SFN7xxx, SFN8xxx, X2xxx) native datapath which is
  more efficient than libefx-based and provides richer packet type
  classification.
  **ef10_essb** chooses SFNX2xxx equal stride super-buffer datapath
  which may be used on DPDK firmware variant only
  (see notes about its limitations above).
  **ef100** chooses EF100 native datapath which is the only supported
  Rx datapath for EF100 architecture based NICs.

- ``tx_datapath`` [auto|efx|ef10|ef10_simple|ef100] (default **auto**)

  Choose transmit datapath implementation.
  **auto** allows the driver itself to make a choice based on firmware
  features available and required by the datapath implementation.
  **efx** chooses libefx-based datapath which supports VLAN insertion
  (full-feature firmware variant only), TSO and multi-segment mbufs.
  Mbuf segments may come from different mempools, and mbuf reference
  counters are treated responsibly.
  Supported for SFN7xxx, SFN8xxx and X2xxx family adapters only.
  **ef10** chooses EF10 (SFN7xxx, SFN8xxx, X2xxx) native datapath which is
  more efficient than libefx-based but has no VLAN insertion support yet.
  Mbuf segments may come from different mempools, and mbuf reference
  counters are treated responsibly.
  **ef10_simple** chooses EF10 (SFN7xxx, SFN8xxx, X2xxx) native datapath which
  is even more faster then **ef10** but does not support multi-segment
  mbufs, disallows multiple mempools and neglects mbuf reference counters.
  **ef100** chooses EF100 native datapath which supports multi-segment
  mbufs, VLAN insertion, inner/outer IPv4 and TCP/UDP checksum and TCP
  segmentation offloads including VXLAN and GENEVE IPv4/IPv6 tunnels.

- ``perf_profile`` [auto|throughput|low-latency] (default **throughput**)

  Choose hardware tuning to be optimized for either throughput or
  low-latency.
  **auto** allows NIC firmware to make a choice based on
  installed licenses and firmware variant configured using **sfboot**.

- ``stats_update_period_ms`` [long] (default **1000**)

  Adjust period in milliseconds to update port hardware statistics.
  The accepted range is 0 to 65535. The value of **0** may be used
  to disable periodic statistics update. One should note that it's
  only possible to set an arbitrary value on SFN8xxx and X2xxx provided that
  firmware version is 6.2.1.1033 or higher, otherwise any positive
  value will select a fixed update period of **1000** milliseconds

- ``fw_variant`` [dont-care|full-feature|ultra-low-latency|
  capture-packed-stream|dpdk] (default **dont-care**)

  Choose the preferred firmware variant to use.
  The parameter is supported for SFN7xxX, SFN8xxx and X2xxx families only.
  In order for the selected option to have an effect, the **sfboot** utility
  must be configured with the **auto** firmware-variant option.
  The preferred firmware variant applies to all ports on the NIC.
  **dont-care** ensures that the driver can attach to an unprivileged function.
  The datapath firmware type to use is controlled by the **sfboot**
  utility.
  **full-feature** chooses full featured firmware.
  **ultra-low-latency** chooses firmware with fewer features but lower latency.
  **capture-packed-stream** chooses firmware for SolarCapture packed stream
  mode.
  **dpdk** chooses DPDK firmware with equal stride super-buffer Rx mode
  for higher Rx packet rate and packet marks support and firmware subvariant
  without checksumming on transmit for higher Tx packet rate if
  checksumming is not required.

- ``rxd_wait_timeout_ns`` [long] (default **200 us**)

  Adjust timeout in nanoseconds to head-of-line block to wait for
  Rx descriptors.
  The accepted range is 0 to 400 ms.
  Flow control should be enabled to make it work.
  The value of **0** disables it and packets are dropped immediately.
  When a packet is dropped because of no Rx descriptors,
  ``rx_nodesc_drop_cnt`` counter grows.
  The feature is supported only by the DPDK firmware variant when equal
  stride super-buffer Rx mode is used.


Dynamic Logging Parameters
~~~~~~~~~~~~~~~~~~~~~~~~~~

One may leverage EAL option "--log-level" to change default levels
for the log types supported by the driver. The option is used with
an argument typically consisting of two parts separated by a colon.

Level value is the last part which takes a symbolic name (or integer).
Log type is the former part which may shell match syntax.
Depending on the choice of the expression, the given log level may
be used either for some specific log type or for a subset of types.

SFC EFX PMD provides the following log types available for control:

- ``pmd.net.sfc.driver`` (default level is **notice**)

  Affects driver-wide messages unrelated to any particular devices.

- ``pmd.net.sfc.main`` (default level is **notice**)

  Matches a subset of per-port log types registered during runtime.
  A full name for a particular type may be obtained by appending a
  dot and a PCI device identifier (``XXXX:XX:XX.X``) to the prefix.

- ``pmd.net.sfc.mcdi`` (default level is **notice**)

  Extra logging of the communication with the NIC's management CPU.
  The format of the log is consumed by the Solarflare netlogdecode
  cross-platform tool. May be managed per-port, as explained above.