14. 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.
14.1. 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
14.1.1. DPAA Overview
Reference: FSL DPAA Architecture.
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.
14.2. 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.
+------------+
| 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.
14.2.1. 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
14.2.2. 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.
14.2.2.1. Features
Features of the DPAA PMD are:
- Multiple queues for TX and RX
- Receive Side Scaling (RSS)
- Packet type information
- Checksum offload
- Promiscuous mode
14.2.3. 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.
14.3. Allowing & Blocking
For blocking a DPAA device, following commands can be used.
<dpdk app> <EAL args> -b "dpaa_bus:fmX-macY" -- ... e.g. "dpaa_bus:fm1-mac4"
14.4. Supported DPAA SoCs
- LS1043A/LS1023A
- LS1046A/LS1026A
14.5. Prerequisites
See NXP QorIQ DPAA Board Support Package for setup information
- Follow the DPDK Getting Started Guide for Linux 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.
14.6. Pre-Installation Configuration
14.6.1. 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.
14.7. Driver compilation and testing
Refer to the document compiling and testing a PMD for a NIC for details.
Running testpmd:
Follow instructions available in the document compiling and testing a PMD for a NIC to run testpmd.
Example output:
./<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>
14.8. 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
14.8.1. 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.
14.8.2. 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.
14.8.3. 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.
14.9. Limitations
14.9.1. Platform Requirement
DPAA drivers for DPDK can only work on NXP SoCs as listed in the
Supported DPAA SoCs.
14.9.2. 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.
14.9.3. 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.