Lines Matching +full:need +full:- +full:phy +full:- +full:for +full:- +full:wake
7 develop drivers for this subsystem as well as a TODO for developers interested
22 An Ethernet switch typically comprises multiple front-panel ports and one
25 receiving Ethernet frames from the switch. This is a very common setup for all
27 gateways, or even top-of-rack switches. This host Ethernet controller will
30 The D in DSA stands for Distributed, because the subsystem has been designed
36 For each front-panel port, DSA creates specialized network devices which are
37 used as controlling and data-flowing endpoints for use by the Linux networking
41 The ideal case for using DSA is when an Ethernet switch supports a "switch tag"
42 which is a hardware feature making the switch insert a specific tag for each
46 - what port is this frame coming from
47 - what was the reason why this frame got forwarded
48 - how to send CPU originated traffic to specific ports
52 on Port-based VLAN IDs).
54 Note that DSA does not currently create network interfaces for the "cpu" and
57 - the "cpu" port is the Ethernet switch facing side of the management
59 would get two interfaces for the same conduit: master netdev, and "cpu" netdev
61 - the "dsa" port(s) are just conduits between two or more switches, and as such
63 downstream, or the top-most upstream interface makes sense with that model
66 ------------------------
68 DSA supports many vendor-specific tagging protocols, one software-defined
69 tagging protocol, and a tag-less mode as well (``DSA_TAG_PROTO_NONE``).
74 - identifies which port the Ethernet frame came from/should be sent to
75 - provides a reason why this frame was forwarded to the management interface
82 1. The switch-specific frame header is located before the Ethernet header,
85 2. The switch-specific frame header is located before the EtherType, keeping
88 3. The switch-specific frame header is located at the tail of the packet,
93 the tag length might vary (for example packets with PTP timestamps might
99 accommodate for this extra size in order for DSA user ports to support the
102 on a best-effort basis, the allocation of packets with enough extra space such
106 Even though applications are not expected to parse DSA-specific frame headers,
108 Interface exposed by the kernel towards user space, for decoders such as
113 stateful processing required to deal with the frames (as may be required for
118 fabric with more than one switch, the switch-specific frame header is inserted
133 It still remains the case that, if the DSA switch tree is configured for the
134 EDSA tagging protocol, the operating system sees EDSA-tagged packets from the
143 tree. The DSA links are viewed as simply a pair of a DSA master (the out-facing
144 port of the upstream DSA switch) and a CPU port (the in-facing port of the
161 regardless of the driver used for the switch control path, and the driver used
162 for the DSA master.
165 The passed ``struct sk_buff *skb`` has ``skb->data`` pointing at
170 understand what egress port the packet is for (and not deliver it towards other
171 ports). Typically this is fulfilled by pushing a frame header. Checking for
177 passed ``struct sk_buff *skb`` has ``skb->data`` pointing at
180 method is to consume the frame header, adjust ``skb->data`` to really point at
181 the first octet after the EtherType, and to change ``skb->dev`` to point to the
182 virtual DSA user network interface corresponding to the physical front-facing
198 csum_offset. For those cases, DSA will shift the checksum start and offset by
206 pseudo IP header sum). For category 3, when the offload hardware does not
214 with DSA-unaware masters, mangling what the master perceives as MAC DA), the
218 Note that this assumes a DSA-unaware master driver, which is the norm.
221 ----------------------
223 Master network devices are regular, unmodified Linux network device drivers for
224 the CPU/management Ethernet interface. Such a driver might occasionally need to
233 ----------------------
238 specific (and fake) Ethernet type (later becoming ``skb->protocol``) with the
246 - receive function is invoked
247 - basic packet processing is done: getting length, status etc.
248 - packet is prepared to be processed by the Ethernet layer by calling
254 if (dev->dsa_ptr != NULL)
255 -> skb->protocol = ETH_P_XDSA
260 -> iterate over registered packet_type
261 -> invoke handler for ETH_P_XDSA, calls dsa_switch_rcv()
265 -> dsa_switch_rcv()
266 -> invoke switch tag specific protocol handler in 'net/dsa/tag_*.c'
270 - inspect and strip switch tag protocol to determine originating port
271 - locate per-port network device
272 - invoke ``eth_type_trans()`` with the DSA slave network device
273 - invoked ``netif_receive_skb()``
279 ---------------------
282 device, each of these network interfaces will be responsible for being a
283 controlling and data-flowing end-point for each front-panel port of the switch.
286 - insert/remove the switch tag protocol (if it exists) when sending traffic
288 - query the switch for ethtool operations: statistics, link state,
289 Wake-on-LAN, register dumps...
290 - manage external/internal PHY: link, auto-negotiation, etc.
301 These frames are then queued for transmission using the master network device
309 masters as well (just with no user port assigned to them; this is needed for
321 ------------------------
330 +-----------v--|--------------------+
331 |+------+ +------+ +------+ +------+|
333 |+------+-+------+-+------+-+------+|
335 +-----------------------------------+
340 +-----------------------------------+
342 --------+-----------------------------------+------------
344 +-----------------------------------+
349 +-----------------------------------+
351 |+------+ +------+ +------+ +------+|
353 ++------+-+------+-+------+-+------++
356 --------------
358 In order to be able to read to/from a switch PHY built into it, DSA creates a
360 MDIO reads/writes towards specific PHY addresses. In most MDIO-connected
361 switches, these functions would utilize direct or indirect PHY addressing mode
362 to return standard MII registers from the switch builtin PHYs, allowing the PHY
363 library and/or to return link status, link partner pages, auto-negotiation
366 For Ethernet switches which have both external and internal MDIO buses, the
372 ---------------
377 - ``dsa_chip_data``: platform data configuration for a given switch device,
382 - ``dsa_platform_data``: platform device configuration data which can reference
387 - ``dsa_switch_tree``: structure assigned to the master network device under
394 - ``dsa_switch``: structure describing a switch device in the tree, referencing
398 - ``dsa_switch_ops``: structure referencing function pointers, see below for a
405 -------------------------------
407 DSA does not currently create slave network devices for the CPU or DSA ports, as
410 - inability to fetch switch CPU port statistics counters using ethtool, which
413 - inability to configure the CPU port link parameters based on the Ethernet
416 - inability to configure specific VLAN IDs / trunking VLANs between switches
420 --------------------------------
422 Once a master network device is configured to use DSA (dev->dsa_ptr becomes
423 non-NULL), and the switch behind it expects a tagging protocol, this network
435 - MDIO/PHY library: ``drivers/net/phy/phy.c``, ``mdio_bus.c``
436 - Switchdev:``net/switchdev/*``
437 - Device Tree for various of_* functions
438 - Devlink: ``net/core/devlink.c``
440 MDIO/PHY library
441 ----------------
443 Slave network devices exposed by DSA may or may not be interfacing with PHY
444 devices (``struct phy_device`` as defined in ``include/linux/phy.h)``, but the DSA
447 - internal PHY devices, built into the Ethernet switch hardware
448 - external PHY devices, connected via an internal or external MDIO bus
449 - internal PHY devices, connected via an internal MDIO bus
450 - special, non-autonegotiated or non MDIO-managed PHY devices: SFPs, MoCA; a.k.a
453 The PHY configuration is done by the ``dsa_slave_phy_setup()`` function and the
456 - if Device Tree is used, the PHY device is looked up using the standard
457 "phy-handle" property, if found, this PHY device is created and registered
460 - if Device Tree is used and the PHY device is "fixed", that is, conforms to
461 the definition of a non-MDIO managed PHY as defined in
462 ``Documentation/devicetree/bindings/net/fixed-link.txt``, the PHY is registered
465 - finally, if the PHY is built into the switch, as is very common with
466 standalone switch packages, the PHY is probed using the slave MII bus created
471 ---------
475 of per-port slave network devices. As of today, the only SWITCHDEV objects
479 -------
482 For each devlink device, every physical port (i.e. user ports, CPU ports, DSA
487 - Regions: debugging feature which allows user space to dump driver-defined
488 areas of hardware information in a low-level, binary format. Both global
489 regions as well as per-port regions are supported. It is possible to export
490 devlink regions even for pieces of data that are already exposed in some way
491 to the standard iproute2 user space programs (ip-link, bridge), like address
492 tables and VLAN tables. For example, this might be useful if the tables
493 contain additional hardware-specific details which are not visible through
495 the non-user ports too, which are invisible to iproute2 because no network
496 interface is registered for them.
497 - Params: a feature which enables user to configure certain low-level tunable
499 devlink params, or may add new device-specific devlink params.
500 - Resources: a monitoring feature which enables users to see the degree of
502 - Shared buffers: a QoS feature for adjusting and partitioning memory and frame
504 directions, such that low-priority bulk traffic does not impede the
505 processing of high-priority critical traffic.
507 For more details, consult ``Documentation/networking/devlink/``.
510 -----------
513 ``Documentation/devicetree/bindings/net/dsa/dsa.txt``. PHY/MDIO library helper
515 per-port PHY specific details: interface connection, MDIO bus location, etc.
520 DSA switch drivers need to implement a ``dsa_switch_ops`` structure which will
524 -----------------------------------------
535 - ``ds->dev``: will be used to parse the switch's OF node or platform data.
537 - ``ds->num_ports``: will be used to create the port list for this switch, and
540 - ``ds->ops``: a pointer to the ``dsa_switch_ops`` structure holding the DSA
543 - ``ds->priv``: backpointer to a driver-private data structure which can be
547 be configured to obtain driver-specific behavior from the DSA core. Their
550 - ``ds->vlan_filtering_is_global``
552 - ``ds->needs_standalone_vlan_filtering``
554 - ``ds->configure_vlan_while_not_filtering``
556 - ``ds->untag_bridge_pvid``
558 - ``ds->assisted_learning_on_cpu_port``
560 - ``ds->mtu_enforcement_ingress``
562 - ``ds->fdb_isolation``
574 The first N-1 callers of ``dsa_register_switch()`` only add their ports to the
575 port list of the tree (``dst->ports``), each port having a backpointer to its
576 associated switch (``dp->ds``). Then, these switches exit their
581 continuation of initialization (including the call to ``ds->ops->setup()``) for
589 It is mandatory for DSA switch drivers to implement the ``shutdown()`` callback
593 driver for the master device decides to unbind on shutdown, DSA's reference
608 --------------------
610 - ``get_tag_protocol``: this is to indicate what kind of tagging protocol is
617 - ``change_tag_protocol``: when the default tagging protocol has compatibility
623 - ``setup``: setup function for the switch, this function is responsible for setting
628 a Port-based VLAN ID for each port and allowing only the CPU port and the
634 may have previously configured. The method responsible for undoing any
637 - ``port_setup`` and ``port_teardown``: methods for initialization and
638 destruction of per-port data structures. It is mandatory for some operations
641 it has been previously set up. It is possible for a port to be set up during
642 probing only to be torn down immediately afterwards, for example in case its
643 PHY cannot be found. In this case, probing of the DSA switch continues
646 - ``port_change_master``: method through which the affinity (association used
647 for traffic termination purposes) between a user port and a CPU port can be
649 available CPU port that makes sense for them (most of the times this means
650 the user ports of a tree are all assigned to the same CPU port, except for H
655 master->dsa_ptr``. Additionally, the master can also be a LAG device where
657 valid ``master->dsa_ptr`` pointer, however this is not unique, but rather a
660 separately for the physical CPU ports associated with the physical DSA
664 PHY devices and link management
665 -------------------------------
667 - ``get_phy_flags``: Some switches are interfaced to various kinds of Ethernet PHYs,
668 if the PHY library PHY driver needs to know about information it cannot obtain
670 should return a 32-bit bitmask of "flags" that is private between the switch
671 driver and the Ethernet PHY driver in ``drivers/net/phy/\*``.
673 - ``phy_read``: Function invoked by the DSA slave MDIO bus when attempting to read
674 the switch port MDIO registers. If unavailable, return 0xffff for each read.
675 For builtin switch Ethernet PHYs, this function should allow reading the link
676 status, auto-negotiation results, link partner pages, etc.
678 - ``phy_write``: Function invoked by the DSA slave MDIO bus when attempting to write
682 - ``adjust_link``: Function invoked by the PHY library when a slave network device
683 is attached to a PHY device. This function is responsible for appropriately
687 - ``fixed_link_update``: Function invoked by the PHY library, and specifically by
688 the fixed PHY driver asking the switch driver for link parameters that could
689 not be auto-negotiated, or obtained by reading the PHY registers through MDIO.
690 This is particularly useful for specific kinds of hardware such as QSGMII,
691 MoCA or other kinds of non-MDIO managed PHYs where out of band link
695 ------------------
697 - ``get_strings``: ethtool function used to query the driver's strings, will
700 - ``get_ethtool_stats``: ethtool function used to query per-port statistics and
705 - ``get_sset_count``: ethtool function used to query the number of statistics items
707 - ``get_wol``: ethtool function used to obtain Wake-on-LAN settings per-port, this
708 function may for certain implementations also query the master network device
709 Wake-on-LAN settings if this interface needs to participate in Wake-on-LAN
711 - ``set_wol``: ethtool function used to configure Wake-on-LAN settings per-port,
714 - ``set_eee``: ethtool function which is used to configure a switch port EEE (Green
715 Ethernet) settings, can optionally invoke the PHY library to enable EEE at the
716 PHY level if relevant. This function should enable EEE at the switch port MAC
717 controller and data-processing logic
719 - ``get_eee``: ethtool function which is used to query a switch port EEE settings,
721 and data-processing logic as well as query the PHY for its currently configured
724 - ``get_eeprom_len``: ethtool function returning for a given switch the EEPROM
727 - ``get_eeprom``: ethtool function returning for a given switch the EEPROM contents
729 - ``set_eeprom``: ethtool function writing specified data to a given switch EEPROM
731 - ``get_regs_len``: ethtool function returning the register length for a given
734 - ``get_regs``: ethtool function returning the Ethernet switch internal register
735 contents. This function might require user-land code in ethtool to
736 pretty-print register values and registers
739 ----------------
741 - ``suspend``: function invoked by the DSA platform device when the system goes to
743 participating in Wake-on-LAN active as well as additional wake-up logic if
746 - ``resume``: function invoked by the DSA platform device when the system resumes,
747 should resume all Ethernet switch activities and re-configure the switch to be
750 - ``port_enable``: function invoked by the DSA slave network device ndo_open
756 - ``port_disable``: function invoked by the DSA slave network device ndo_close
763 -----------------
765 Switching hardware is expected to have a table for FDB entries, however not all
772 For example, all ports that belong to a VLAN-unaware bridge (which is
773 *currently* VLAN-unaware) are expected to learn source addresses in the
775 VLAN-unaware bridges). During forwarding and FDB lookup, a packet received on a
776 VLAN-unaware bridge port should be able to find a VLAN-unaware FDB entry having
780 a port which is a member of a different VLAN-unaware bridge (and is therefore
783 Similarly, each VLAN of each offloaded VLAN-aware bridge should have an
788 In this context, a VLAN-unaware database means that all packets are expected to
790 VLAN-aware database means that packets are supposed to match based on the VLAN
793 At the bridge layer, VLAN-unaware FDB entries have the special VID value of 0,
794 whereas VLAN-aware FDB entries have non-zero VID values. Note that a
795 VLAN-unaware bridge may have VLAN-aware (non-zero VID) FDB entries, and a
796 VLAN-aware bridge may have VLAN-unaware FDB entries. As in hardware, the
804 (packet in, packet out to the CPU port) as little as possible. For example,
821 for which it is known that software is interested in those MAC addresses.
823 which will save CPU cycles required for creating an skb just to drop it.
825 DSA is able to perform host address filtering for the following kinds of
828 - Primary unicast MAC addresses of ports (``dev->dev_addr``). These are
833 - Secondary unicast and multicast MAC addresses of ports (addresses added
837 - Local/permanent bridge FDB entries (``BR_FDB_LOCAL``). These are the MAC
838 addresses of the bridge ports, for which packets must be terminated locally
839 and not forwarded. They are associated with the address database for that
842 - Static bridge FDB entries installed towards foreign (non-DSA) interfaces
844 associated with the address database for that bridge.
846 - Dynamically learned FDB entries on foreign interfaces present in the same
847 bridge as some DSA switch ports, only if ``ds->assisted_learning_on_cpu_port``
849 for that bridge.
851 For various operations detailed below, DSA provides a ``dsa_db`` structure
854 - ``DSA_DB_PORT``: the FDB (or MDB) entry to be installed or deleted belongs to
855 the port private database of user port ``db->dp``.
856 - ``DSA_DB_BRIDGE``: the entry belongs to one of the address databases of bridge
857 ``db->bridge``. Separation between the VLAN-unaware database and the per-VID
859 - ``DSA_DB_LAG``: the entry belongs to the address database of LAG ``db->lag``.
863 ``port_mdb_add`` etc should declare ``ds->fdb_isolation`` as true.
865 DSA associates each offloaded bridge and each offloaded LAG with a one-based ID
866 (``struct dsa_bridge :: num``, ``struct dsa_lag :: id``) for the purposes of
868 scheme (the ID is readable through ``db->bridge.num`` and ``db->lag.id`` or may
871 Only the drivers which declare support for FDB isolation are notified of FDB
873 For compatibility/legacy reasons, ``DSA_DB_BRIDGE`` addresses are notified to
874 drivers even if they do not support FDB isolation. However, ``db->bridge.num``
875 and ``db->lag.id`` are always set to 0 in that case (to denote the lack of
876 isolation, for refcounting purposes).
878 Note that it is not mandatory for a switch driver to implement physically
879 separate address databases for each standalone user port. Since FDB entries in
881 for incorrect forwarding decisions. In this case, all standalone ports may
882 share the same database, but the reference counting of host-filtered addresses
883 (not deleting the FDB entry for a port's MAC address if it's still in use by
893 ------------
896 below. They may be absent, return -EOPNOTSUPP, or ``ds->max_num_bridges`` may
897 be non-zero and exceeded, and in this case, joining a bridge port is still
899 under a software bridge must remain configured in the same way as for
909 are expected to call ``dsa_default_offload_fwd_mark(skb)`` for packets which
921 Packets for which the bridge requests this behavior are called data plane
922 packets and have ``skb->offload_fwd_mark`` set to true in the tag protocol
926 handled in hardware and the bridge driver will transmit a single skb for each
927 packet that may or may not need replication.
932 VLAN-unaware, and in this case the FID must be equal to the FID used by the
933 driver for its VLAN-unaware address database associated with that bridge.
934 Alternatively, the bridge may be VLAN-aware, and in that case, it is guaranteed
935 that the packet is also VLAN-tagged with the VLAN ID that the bridge processed
937 the egress-untagged ports, or keep the tag on the egress-tagged ones.
939 - ``port_bridge_join``: bridge layer function invoked when a given switch port is
942 domain for it to ingress/egress traffic with other members of the bridge.
946 - ``port_bridge_leave``: bridge layer function invoked when a given switch port is
951 - ``port_stp_state_set``: bridge layer function invoked when a given switch port STP
955 - ``port_bridge_flags``: bridge layer function invoked when a port must
956 configure its settings for e.g. flooding of unknown traffic or source address
957 learning. The switch driver is responsible for initial setup of the
961 the bridge port flags for the CPU port. The assumption is that address
966 - ``port_fast_age``: bridge layer function invoked when flushing the
973 ---------------------
975 - ``port_vlan_filtering``: bridge layer function invoked when the bridge gets
976 configured for turning on or off VLAN filtering. If nothing specific needs to
977 be done at the hardware level, this callback does not need to be implemented.
985 - ``port_vlan_add``: bridge layer function invoked when a VLAN is configured
986 (tagged or untagged) for the given switch port. The CPU port becomes a member
989 VLAN group of the bridge device itself, for termination purposes
991 reference counted and removed when there is no user left. Drivers do not need
994 - ``port_vlan_del``: bridge layer function invoked when a VLAN is removed from the
997 - ``port_fdb_add``: bridge layer function invoked when the bridge wants to install a
1002 - ``port_fdb_del``: bridge layer function invoked when the bridge wants to remove a
1007 - ``port_fdb_dump``: bridge bypass function invoked by ``ndo_fdb_dump`` on the
1014 - ``port_mdb_add``: bridge layer function invoked when the bridge wants to install
1019 - ``port_mdb_del``: bridge layer function invoked when the bridge wants to remove a
1025 ----------------
1042 - ``port_lag_join``: function invoked when a given switch port is added to a
1043 LAG. The driver may return ``-EOPNOTSUPP``, and in this case, DSA will fall
1046 - ``port_lag_leave``: function invoked when a given switch port leaves a LAG
1048 - ``port_lag_change``: function invoked when the link state of any member of
1053 can optionally populate ``ds->num_lag_ids`` from the ``dsa_switch_ops::setup``
1057 IEC 62439-2 (MRP)
1058 -----------------
1060 The Media Redundancy Protocol is a topology management protocol optimized for
1061 fast fault recovery time for ring networks, which has some components
1067 PDUs might need to be terminated locally and others might need to be forwarded.
1073 necessary for the hardware, even if it is not MRP-aware, to be able to extract
1075 implementation. DSA today has no driver which is MRP-aware, therefore it only
1076 listens for the bare minimum switchdev objects required for the software assist
1079 - ``port_mrp_add`` and ``port_mrp_del``: notifies driver when an MRP instance
1082 - ``port_mrp_add_ring_role`` and ``port_mrp_del_ring_role``: function invoked
1087 IEC 62439-3 (HSR/PRP)
1088 ---------------------
1093 eliminating the duplicates at the receiver. The High-availability Seamless
1095 the redundant traffic are aware of the fact that it is HSR-tagged (because HSR
1097 ring topology. Both HSR and PRP use supervision frames for monitoring the
1098 health of the network and for discovery of other nodes.
1109 ``Documentation/networking/netdev-features.rst``. Additionally, the following
1112 - ``port_hsr_join``: function invoked when a given switch port is added to a
1113 DANP/DANH. The driver may return ``-EOPNOTSUPP`` and in this case, DSA will
1116 - ``port_hsr_leave``: function invoked when a given switch port leaves a
1123 -------------------------------------------------------------