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diff --git a/Documentation/networking/device_drivers/freescale/dpaa.txt b/Documentation/networking/device_drivers/freescale/dpaa.txt deleted file mode 100644 index b06601ff9200..000000000000 --- a/Documentation/networking/device_drivers/freescale/dpaa.txt +++ /dev/null @@ -1,260 +0,0 @@ -The QorIQ DPAA Ethernet Driver -============================== - -Authors: -Madalin Bucur <madalin.bucur@nxp.com> -Camelia Groza <camelia.groza@nxp.com> - -Contents -======== - - - DPAA Ethernet Overview - - DPAA Ethernet Supported SoCs - - Configuring DPAA Ethernet in your kernel - - DPAA Ethernet Frame Processing - - DPAA Ethernet Features - - DPAA IRQ Affinity and Receive Side Scaling - - Debugging - -DPAA Ethernet Overview -====================== - -DPAA stands for Data Path Acceleration Architecture and it is a -set of networking acceleration IPs that are available on several -generations of SoCs, both on PowerPC and ARM64. - -The Freescale DPAA architecture consists of a series of hardware blocks -that support Ethernet connectivity. The Ethernet driver depends upon the -following drivers in the Linux kernel: - - - Peripheral Access Memory Unit (PAMU) (* needed only for PPC platforms) - drivers/iommu/fsl_* - - Frame Manager (FMan) - drivers/net/ethernet/freescale/fman - - Queue Manager (QMan), Buffer Manager (BMan) - drivers/soc/fsl/qbman - -A simplified view of the dpaa_eth interfaces mapped to FMan MACs: - - dpaa_eth /eth0\ ... /ethN\ - driver | | | | - ------------- ---- ----------- ---- ------------- - -Ports / Tx Rx \ ... / Tx Rx \ - FMan | | | | - -MACs | MAC0 | | MACN | - / dtsec0 \ ... / dtsecN \ (or tgec) - / \ / \(or memac) - --------- -------------- --- -------------- --------- - FMan, FMan Port, FMan SP, FMan MURAM drivers - --------------------------------------------------------- - FMan HW blocks: MURAM, MACs, Ports, SP - --------------------------------------------------------- - -The dpaa_eth relation to the QMan, BMan and FMan: - ________________________________ - dpaa_eth / eth0 \ - driver / \ - --------- -^- -^- -^- --- --------- - QMan driver / \ / \ / \ \ / | BMan | - |Rx | |Rx | |Tx | |Tx | | driver | - --------- |Dfl| |Err| |Cnf| |FQs| | | - QMan HW |FQ | |FQ | |FQs| | | | | - / \ / \ / \ \ / | | - --------- --- --- --- -v- --------- - | FMan QMI | | - | FMan HW FMan BMI | BMan HW | - ----------------------- -------- - -where the acronyms used above (and in the code) are: -DPAA = Data Path Acceleration Architecture -FMan = DPAA Frame Manager -QMan = DPAA Queue Manager -BMan = DPAA Buffers Manager -QMI = QMan interface in FMan -BMI = BMan interface in FMan -FMan SP = FMan Storage Profiles -MURAM = Multi-user RAM in FMan -FQ = QMan Frame Queue -Rx Dfl FQ = default reception FQ -Rx Err FQ = Rx error frames FQ -Tx Cnf FQ = Tx confirmation FQs -Tx FQs = transmission frame queues -dtsec = datapath three speed Ethernet controller (10/100/1000 Mbps) -tgec = ten gigabit Ethernet controller (10 Gbps) -memac = multirate Ethernet MAC (10/100/1000/10000) - -DPAA Ethernet Supported SoCs -============================ - -The DPAA drivers enable the Ethernet controllers present on the following SoCs: - -# PPC -P1023 -P2041 -P3041 -P4080 -P5020 -P5040 -T1023 -T1024 -T1040 -T1042 -T2080 -T4240 -B4860 - -# ARM -LS1043A -LS1046A - -Configuring DPAA Ethernet in your kernel -======================================== - -To enable the DPAA Ethernet driver, the following Kconfig options are required: - -# common for arch/arm64 and arch/powerpc platforms -CONFIG_FSL_DPAA=y -CONFIG_FSL_FMAN=y -CONFIG_FSL_DPAA_ETH=y -CONFIG_FSL_XGMAC_MDIO=y - -# for arch/powerpc only -CONFIG_FSL_PAMU=y - -# common options needed for the PHYs used on the RDBs -CONFIG_VITESSE_PHY=y -CONFIG_REALTEK_PHY=y -CONFIG_AQUANTIA_PHY=y - -DPAA Ethernet Frame Processing -============================== - -On Rx, buffers for the incoming frames are retrieved from the buffers found -in the dedicated interface buffer pool. The driver initializes and seeds these -with one page buffers. - -On Tx, all transmitted frames are returned to the driver through Tx -confirmation frame queues. The driver is then responsible for freeing the -buffers. In order to do this properly, a backpointer is added to the buffer -before transmission that points to the skb. When the buffer returns to the -driver on a confirmation FQ, the skb can be correctly consumed. - -DPAA Ethernet Features -====================== - -Currently the DPAA Ethernet driver enables the basic features required for -a Linux Ethernet driver. The support for advanced features will be added -gradually. - -The driver has Rx and Tx checksum offloading for UDP and TCP. Currently the Rx -checksum offload feature is enabled by default and cannot be controlled through -ethtool. Also, rx-flow-hash and rx-hashing was added. The addition of RSS -provides a big performance boost for the forwarding scenarios, allowing -different traffic flows received by one interface to be processed by different -CPUs in parallel. - -The driver has support for multiple prioritized Tx traffic classes. Priorities -range from 0 (lowest) to 3 (highest). These are mapped to HW workqueues with -strict priority levels. Each traffic class contains NR_CPU TX queues. By -default, only one traffic class is enabled and the lowest priority Tx queues -are used. Higher priority traffic classes can be enabled with the mqprio -qdisc. For example, all four traffic classes are enabled on an interface with -the following command. Furthermore, skb priority levels are mapped to traffic -classes as follows: - - * priorities 0 to 3 - traffic class 0 (low priority) - * priorities 4 to 7 - traffic class 1 (medium-low priority) - * priorities 8 to 11 - traffic class 2 (medium-high priority) - * priorities 12 to 15 - traffic class 3 (high priority) - -tc qdisc add dev <int> root handle 1: \ - mqprio num_tc 4 map 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3 hw 1 - -DPAA IRQ Affinity and Receive Side Scaling -========================================== - -Traffic coming on the DPAA Rx queues or on the DPAA Tx confirmation -queues is seen by the CPU as ingress traffic on a certain portal. -The DPAA QMan portal interrupts are affined each to a certain CPU. -The same portal interrupt services all the QMan portal consumers. - -By default the DPAA Ethernet driver enables RSS, making use of the -DPAA FMan Parser and Keygen blocks to distribute traffic on 128 -hardware frame queues using a hash on IP v4/v6 source and destination -and L4 source and destination ports, in present in the received frame. -When RSS is disabled, all traffic received by a certain interface is -received on the default Rx frame queue. The default DPAA Rx frame -queues are configured to put the received traffic into a pool channel -that allows any available CPU portal to dequeue the ingress traffic. -The default frame queues have the HOLDACTIVE option set, ensuring that -traffic bursts from a certain queue are serviced by the same CPU. -This ensures a very low rate of frame reordering. A drawback of this -is that only one CPU at a time can service the traffic received by a -certain interface when RSS is not enabled. - -To implement RSS, the DPAA Ethernet driver allocates an extra set of -128 Rx frame queues that are configured to dedicated channels, in a -round-robin manner. The mapping of the frame queues to CPUs is now -hardcoded, there is no indirection table to move traffic for a certain -FQ (hash result) to another CPU. The ingress traffic arriving on one -of these frame queues will arrive at the same portal and will always -be processed by the same CPU. This ensures intra-flow order preservation -and workload distribution for multiple traffic flows. - -RSS can be turned off for a certain interface using ethtool, i.e. - - # ethtool -N fm1-mac9 rx-flow-hash tcp4 "" - -To turn it back on, one needs to set rx-flow-hash for tcp4/6 or udp4/6: - - # ethtool -N fm1-mac9 rx-flow-hash udp4 sfdn - -There is no independent control for individual protocols, any command -run for one of tcp4|udp4|ah4|esp4|sctp4|tcp6|udp6|ah6|esp6|sctp6 is -going to control the rx-flow-hashing for all protocols on that interface. - -Besides using the FMan Keygen computed hash for spreading traffic on the -128 Rx FQs, the DPAA Ethernet driver also sets the skb hash value when -the NETIF_F_RXHASH feature is on (active by default). This can be turned -on or off through ethtool, i.e.: - - # ethtool -K fm1-mac9 rx-hashing off - # ethtool -k fm1-mac9 | grep hash - receive-hashing: off - # ethtool -K fm1-mac9 rx-hashing on - Actual changes: - receive-hashing: on - # ethtool -k fm1-mac9 | grep hash - receive-hashing: on - -Please note that Rx hashing depends upon the rx-flow-hashing being on -for that interface - turning off rx-flow-hashing will also disable the -rx-hashing (without ethtool reporting it as off as that depends on the -NETIF_F_RXHASH feature flag). - -Debugging -========= - -The following statistics are exported for each interface through ethtool: - - - interrupt count per CPU - - Rx packets count per CPU - - Tx packets count per CPU - - Tx confirmed packets count per CPU - - Tx S/G frames count per CPU - - Tx error count per CPU - - Rx error count per CPU - - Rx error count per type - - congestion related statistics: - - congestion status - - time spent in congestion - - number of time the device entered congestion - - dropped packets count per cause - -The driver also exports the following information in sysfs: - - - the FQ IDs for each FQ type - /sys/devices/platform/soc/<addr>.fman/<addr>.ethernet/dpaa-ethernet.<id>/net/fm<nr>-mac<nr>/fqids - - - the ID of the buffer pool in use - /sys/devices/platform/soc/<addr>.fman/<addr>.ethernet/dpaa-ethernet.<id>/net/fm<nr>-mac<nr>/bpids |