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: conduit 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
65 NB: for the past 15 years, the DSA subsystem had been making use of the terms
70 ------------------------
72 DSA supports many vendor-specific tagging protocols, one software-defined
73 tagging protocol, and a tag-less mode as well (``DSA_TAG_PROTO_NONE``).
78 - identifies which port the Ethernet frame came from/should be sent to
79 - provides a reason why this frame was forwarded to the management interface
86 1. The switch-specific frame header is located before the Ethernet header,
89 2. The switch-specific frame header is located before the EtherType, keeping
92 3. The switch-specific frame header is located at the tail of the packet,
97 the tag length might vary (for example packets with PTP timestamps might
103 accommodate for this extra size in order for DSA user ports to support the
106 on a best-effort basis, the allocation of packets with enough extra space such
110 Even though applications are not expected to parse DSA-specific frame headers,
112 Interface exposed by the kernel towards user space, for decoders such as
117 stateful processing required to deal with the frames (as may be required for
122 fabric with more than one switch, the switch-specific frame header is inserted
137 It still remains the case that, if the DSA switch tree is configured for the
138 EDSA tagging protocol, the operating system sees EDSA-tagged packets from the
147 tree. The DSA links are viewed as simply a pair of a DSA conduit (the out-facing
148 port of the upstream DSA switch) and a CPU port (the in-facing port of the
165 regardless of the driver used for the switch control path, and the driver used
166 for the DSA conduit.
169 The passed ``struct sk_buff *skb`` has ``skb->data`` pointing at
174 understand what egress port the packet is for (and not deliver it towards other
175 ports). Typically this is fulfilled by pushing a frame header. Checking for
181 passed ``struct sk_buff *skb`` has ``skb->data`` pointing at
184 method is to consume the frame header, adjust ``skb->data`` to really point at
185 the first octet after the EtherType, and to change ``skb->dev`` to point to the
186 virtual DSA user network interface corresponding to the physical front-facing
202 csum_offset. For those cases, DSA will shift the checksum start and offset by
210 pseudo IP header sum). For category 3, when the offload hardware does not
218 with DSA-unaware conduits, mangling what the conduit perceives as MAC DA), the
222 Note that this assumes a DSA-unaware conduit driver, which is the norm.
225 -----------------------
227 Conduit network devices are regular, unmodified Linux network device drivers for
228 the CPU/management Ethernet interface. Such a driver might occasionally need to
237 ----------------------
242 specific (and fake) Ethernet type (later becoming ``skb->protocol``) with the
250 - receive function is invoked
251 - basic packet processing is done: getting length, status etc.
252 - packet is prepared to be processed by the Ethernet layer by calling
258 if (dev->dsa_ptr != NULL)
259 -> skb->protocol = ETH_P_XDSA
264 -> iterate over registered packet_type
265 -> invoke handler for ETH_P_XDSA, calls dsa_switch_rcv()
269 -> dsa_switch_rcv()
270 -> invoke switch tag specific protocol handler in 'net/dsa/tag_*.c'
274 - inspect and strip switch tag protocol to determine originating port
275 - locate per-port network device
276 - invoke ``eth_type_trans()`` with the DSA user network device
277 - invoked ``netif_receive_skb()``
283 --------------------
286 device, each of these network interfaces will be responsible for being a
287 controlling and data-flowing end-point for each front-panel port of the switch.
290 - insert/remove the switch tag protocol (if it exists) when sending traffic
292 - query the switch for ethtool operations: statistics, link state,
293 Wake-on-LAN, register dumps...
294 - manage external/internal PHY: link, auto-negotiation, etc.
305 These frames are then queued for transmission using the conduit network device
313 conduits as well (just with no user port assigned to them; this is needed for
325 ------------------------
334 +-----------v--|--------------------+
335 |+------+ +------+ +------+ +------+|
337 |+------+-+------+-+------+-+------+|
339 +-----------------------------------+
344 +-----------------------------------+
346 --------+-----------------------------------+------------
348 +-----------------------------------+
353 +-----------------------------------+
355 |+------+ +------+ +------+ +------+|
357 ++------+-+------+-+------+-+------++
360 -------------
362 In order to be able to read to/from a switch PHY built into it, DSA creates an
364 MDIO reads/writes towards specific PHY addresses. In most MDIO-connected
365 switches, these functions would utilize direct or indirect PHY addressing mode
366 to return standard MII registers from the switch builtin PHYs, allowing the PHY
367 library and/or to return link status, link partner pages, auto-negotiation
370 For Ethernet switches which have both external and internal MDIO buses, the
376 ---------------
381 - ``dsa_chip_data``: platform data configuration for a given switch device,
386 - ``dsa_platform_data``: platform device configuration data which can reference
391 - ``dsa_switch_tree``: structure assigned to the conduit network device under
398 - ``dsa_switch``: structure describing a switch device in the tree, referencing
402 - ``dsa_switch_ops``: structure referencing function pointers, see below for a
409 -------------------------------
411 DSA does not currently create user network devices for the CPU or DSA ports, as
414 - inability to fetch switch CPU port statistics counters using ethtool, which
417 - inability to configure the CPU port link parameters based on the Ethernet
420 - inability to configure specific VLAN IDs / trunking VLANs between switches
424 --------------------------------
426 Once a conduit network device is configured to use DSA (dev->dsa_ptr becomes
427 non-NULL), and the switch behind it expects a tagging protocol, this network
439 - MDIO/PHY library: ``drivers/net/phy/phy.c``, ``mdio_bus.c``
440 - Switchdev:``net/switchdev/*``
441 - Device Tree for various of_* functions
442 - Devlink: ``net/core/devlink.c``
444 MDIO/PHY library
445 ----------------
447 User network devices exposed by DSA may or may not be interfacing with PHY
448 devices (``struct phy_device`` as defined in ``include/linux/phy.h)``, but the DSA
451 - internal PHY devices, built into the Ethernet switch hardware
452 - external PHY devices, connected via an internal or external MDIO bus
453 - internal PHY devices, connected via an internal MDIO bus
454 - special, non-autonegotiated or non MDIO-managed PHY devices: SFPs, MoCA; a.k.a
457 The PHY configuration is done by the ``dsa_user_phy_setup()`` function and the
460 - if Device Tree is used, the PHY device is looked up using the standard
461 "phy-handle" property, if found, this PHY device is created and registered
464 - if Device Tree is used and the PHY device is "fixed", that is, conforms to
465 the definition of a non-MDIO managed PHY as defined in
466 ``Documentation/devicetree/bindings/net/fixed-link.txt``, the PHY is registered
469 - finally, if the PHY is built into the switch, as is very common with
470 standalone switch packages, the PHY is probed using the user MII bus created
475 ---------
479 of per-port user network devices. As of today, the only SWITCHDEV objects
483 -------
486 For each devlink device, every physical port (i.e. user ports, CPU ports, DSA
491 - Regions: debugging feature which allows user space to dump driver-defined
492 areas of hardware information in a low-level, binary format. Both global
493 regions as well as per-port regions are supported. It is possible to export
494 devlink regions even for pieces of data that are already exposed in some way
495 to the standard iproute2 user space programs (ip-link, bridge), like address
496 tables and VLAN tables. For example, this might be useful if the tables
497 contain additional hardware-specific details which are not visible through
499 the non-user ports too, which are invisible to iproute2 because no network
500 interface is registered for them.
501 - Params: a feature which enables user to configure certain low-level tunable
503 devlink params, or may add new device-specific devlink params.
504 - Resources: a monitoring feature which enables users to see the degree of
506 - Shared buffers: a QoS feature for adjusting and partitioning memory and frame
508 directions, such that low-priority bulk traffic does not impede the
509 processing of high-priority critical traffic.
511 For more details, consult ``Documentation/networking/devlink/``.
514 -----------
517 ``Documentation/devicetree/bindings/net/dsa/dsa.txt``. PHY/MDIO library helper
519 per-port PHY specific details: interface connection, MDIO bus location, etc.
524 DSA switch drivers need to implement a ``dsa_switch_ops`` structure which will
528 -----------------------------------------
539 - ``ds->dev``: will be used to parse the switch's OF node or platform data.
541 - ``ds->num_ports``: will be used to create the port list for this switch, and
544 - ``ds->ops``: a pointer to the ``dsa_switch_ops`` structure holding the DSA
547 - ``ds->priv``: backpointer to a driver-private data structure which can be
551 be configured to obtain driver-specific behavior from the DSA core. Their
554 - ``ds->vlan_filtering_is_global``
556 - ``ds->needs_standalone_vlan_filtering``
558 - ``ds->configure_vlan_while_not_filtering``
560 - ``ds->untag_bridge_pvid``
562 - ``ds->assisted_learning_on_cpu_port``
564 - ``ds->mtu_enforcement_ingress``
566 - ``ds->fdb_isolation``
578 The first N-1 callers of ``dsa_register_switch()`` only add their ports to the
579 port list of the tree (``dst->ports``), each port having a backpointer to its
580 associated switch (``dp->ds``). Then, these switches exit their
585 continuation of initialization (including the call to ``ds->ops->setup()``) for
593 It is mandatory for DSA switch drivers to implement the ``shutdown()`` callback
597 driver for the conduit device decides to unbind on shutdown, DSA's reference
612 --------------------
614 - ``get_tag_protocol``: this is to indicate what kind of tagging protocol is
621 - ``change_tag_protocol``: when the default tagging protocol has compatibility
627 - ``setup``: setup function for the switch, this function is responsible for setting
632 a Port-based VLAN ID for each port and allowing only the CPU port and the
638 may have previously configured. The method responsible for undoing any
641 - ``port_setup`` and ``port_teardown``: methods for initialization and
642 destruction of per-port data structures. It is mandatory for some operations
645 it has been previously set up. It is possible for a port to be set up during
646 probing only to be torn down immediately afterwards, for example in case its
647 PHY cannot be found. In this case, probing of the DSA switch continues
650 - ``port_change_conduit``: method through which the affinity (association used
651 for traffic termination purposes) between a user port and a CPU port can be
653 available CPU port that makes sense for them (most of the times this means
654 the user ports of a tree are all assigned to the same CPU port, except for H
659 conduit->dsa_ptr``. Additionally, the conduit can also be a LAG device where
661 valid ``conduit->dsa_ptr`` pointer, however this is not unique, but rather a
664 separately for the physical CPU ports associated with the physical DSA
668 PHY devices and link management
669 -------------------------------
671 - ``get_phy_flags``: Some switches are interfaced to various kinds of Ethernet PHYs,
672 if the PHY library PHY driver needs to know about information it cannot obtain
674 should return a 32-bit bitmask of "flags" that is private between the switch
675 driver and the Ethernet PHY driver in ``drivers/net/phy/\*``.
677 - ``phy_read``: Function invoked by the DSA user MDIO bus when attempting to read
678 the switch port MDIO registers. If unavailable, return 0xffff for each read.
679 For builtin switch Ethernet PHYs, this function should allow reading the link
680 status, auto-negotiation results, link partner pages, etc.
682 - ``phy_write``: Function invoked by the DSA user MDIO bus when attempting to write
686 - ``adjust_link``: Function invoked by the PHY library when a user network device
687 is attached to a PHY device. This function is responsible for appropriately
691 - ``fixed_link_update``: Function invoked by the PHY library, and specifically by
692 the fixed PHY driver asking the switch driver for link parameters that could
693 not be auto-negotiated, or obtained by reading the PHY registers through MDIO.
694 This is particularly useful for specific kinds of hardware such as QSGMII,
695 MoCA or other kinds of non-MDIO managed PHYs where out of band link
699 ------------------
701 - ``get_strings``: ethtool function used to query the driver's strings, will
704 - ``get_ethtool_stats``: ethtool function used to query per-port statistics and
709 - ``get_sset_count``: ethtool function used to query the number of statistics items
711 - ``get_wol``: ethtool function used to obtain Wake-on-LAN settings per-port, this
712 function may for certain implementations also query the conduit network device
713 Wake-on-LAN settings if this interface needs to participate in Wake-on-LAN
715 - ``set_wol``: ethtool function used to configure Wake-on-LAN settings per-port,
718 - ``set_eee``: ethtool function which is used to configure a switch port EEE (Green
719 Ethernet) settings, can optionally invoke the PHY library to enable EEE at the
720 PHY level if relevant. This function should enable EEE at the switch port MAC
721 controller and data-processing logic
723 - ``get_eee``: ethtool function which is used to query a switch port EEE settings,
725 and data-processing logic as well as query the PHY for its currently configured
728 - ``get_eeprom_len``: ethtool function returning for a given switch the EEPROM
731 - ``get_eeprom``: ethtool function returning for a given switch the EEPROM contents
733 - ``set_eeprom``: ethtool function writing specified data to a given switch EEPROM
735 - ``get_regs_len``: ethtool function returning the register length for a given
738 - ``get_regs``: ethtool function returning the Ethernet switch internal register
739 contents. This function might require user-land code in ethtool to
740 pretty-print register values and registers
743 ----------------
745 - ``suspend``: function invoked by the DSA platform device when the system goes to
747 participating in Wake-on-LAN active as well as additional wake-up logic if
750 - ``resume``: function invoked by the DSA platform device when the system resumes,
751 should resume all Ethernet switch activities and re-configure the switch to be
754 - ``port_enable``: function invoked by the DSA user network device ndo_open
760 - ``port_disable``: function invoked by the DSA user network device ndo_close
767 -----------------
769 Switching hardware is expected to have a table for FDB entries, however not all
776 For example, all ports that belong to a VLAN-unaware bridge (which is
777 *currently* VLAN-unaware) are expected to learn source addresses in the
779 VLAN-unaware bridges). During forwarding and FDB lookup, a packet received on a
780 VLAN-unaware bridge port should be able to find a VLAN-unaware FDB entry having
784 a port which is a member of a different VLAN-unaware bridge (and is therefore
787 Similarly, each VLAN of each offloaded VLAN-aware bridge should have an
792 In this context, a VLAN-unaware database means that all packets are expected to
794 VLAN-aware database means that packets are supposed to match based on the VLAN
797 At the bridge layer, VLAN-unaware FDB entries have the special VID value of 0,
798 whereas VLAN-aware FDB entries have non-zero VID values. Note that a
799 VLAN-unaware bridge may have VLAN-aware (non-zero VID) FDB entries, and a
800 VLAN-aware bridge may have VLAN-unaware FDB entries. As in hardware, the
808 (packet in, packet out to the CPU port) as little as possible. For example,
825 for which it is known that software is interested in those MAC addresses.
827 which will save CPU cycles required for creating an skb just to drop it.
829 DSA is able to perform host address filtering for the following kinds of
832 - Primary unicast MAC addresses of ports (``dev->dev_addr``). These are
837 - Secondary unicast and multicast MAC addresses of ports (addresses added
841 - Local/permanent bridge FDB entries (``BR_FDB_LOCAL``). These are the MAC
842 addresses of the bridge ports, for which packets must be terminated locally
843 and not forwarded. They are associated with the address database for that
846 - Static bridge FDB entries installed towards foreign (non-DSA) interfaces
848 associated with the address database for that bridge.
850 - Dynamically learned FDB entries on foreign interfaces present in the same
851 bridge as some DSA switch ports, only if ``ds->assisted_learning_on_cpu_port``
853 for that bridge.
855 For various operations detailed below, DSA provides a ``dsa_db`` structure
858 - ``DSA_DB_PORT``: the FDB (or MDB) entry to be installed or deleted belongs to
859 the port private database of user port ``db->dp``.
860 - ``DSA_DB_BRIDGE``: the entry belongs to one of the address databases of bridge
861 ``db->bridge``. Separation between the VLAN-unaware database and the per-VID
863 - ``DSA_DB_LAG``: the entry belongs to the address database of LAG ``db->lag``.
867 ``port_mdb_add`` etc should declare ``ds->fdb_isolation`` as true.
869 DSA associates each offloaded bridge and each offloaded LAG with a one-based ID
870 (``struct dsa_bridge :: num``, ``struct dsa_lag :: id``) for the purposes of
872 scheme (the ID is readable through ``db->bridge.num`` and ``db->lag.id`` or may
875 Only the drivers which declare support for FDB isolation are notified of FDB
877 For compatibility/legacy reasons, ``DSA_DB_BRIDGE`` addresses are notified to
878 drivers even if they do not support FDB isolation. However, ``db->bridge.num``
879 and ``db->lag.id`` are always set to 0 in that case (to denote the lack of
880 isolation, for refcounting purposes).
882 Note that it is not mandatory for a switch driver to implement physically
883 separate address databases for each standalone user port. Since FDB entries in
885 for incorrect forwarding decisions. In this case, all standalone ports may
886 share the same database, but the reference counting of host-filtered addresses
887 (not deleting the FDB entry for a port's MAC address if it's still in use by
897 ------------
900 below. They may be absent, return -EOPNOTSUPP, or ``ds->max_num_bridges`` may
901 be non-zero and exceeded, and in this case, joining a bridge port is still
903 under a software bridge must remain configured in the same way as for
913 are expected to call ``dsa_default_offload_fwd_mark(skb)`` for packets which
925 Packets for which the bridge requests this behavior are called data plane
926 packets and have ``skb->offload_fwd_mark`` set to true in the tag protocol
930 handled in hardware and the bridge driver will transmit a single skb for each
931 packet that may or may not need replication.
936 VLAN-unaware, and in this case the FID must be equal to the FID used by the
937 driver for its VLAN-unaware address database associated with that bridge.
938 Alternatively, the bridge may be VLAN-aware, and in that case, it is guaranteed
939 that the packet is also VLAN-tagged with the VLAN ID that the bridge processed
941 the egress-untagged ports, or keep the tag on the egress-tagged ones.
943 - ``port_bridge_join``: bridge layer function invoked when a given switch port is
946 domain for it to ingress/egress traffic with other members of the bridge.
950 - ``port_bridge_leave``: bridge layer function invoked when a given switch port is
955 - ``port_stp_state_set``: bridge layer function invoked when a given switch port STP
959 - ``port_bridge_flags``: bridge layer function invoked when a port must
960 configure its settings for e.g. flooding of unknown traffic or source address
961 learning. The switch driver is responsible for initial setup of the
965 the bridge port flags for the CPU port. The assumption is that address
970 - ``port_fast_age``: bridge layer function invoked when flushing the
977 ---------------------
979 - ``port_vlan_filtering``: bridge layer function invoked when the bridge gets
980 configured for turning on or off VLAN filtering. If nothing specific needs to
981 be done at the hardware level, this callback does not need to be implemented.
989 - ``port_vlan_add``: bridge layer function invoked when a VLAN is configured
990 (tagged or untagged) for the given switch port. The CPU port becomes a member
993 VLAN group of the bridge device itself, for termination purposes
995 reference counted and removed when there is no user left. Drivers do not need
998 - ``port_vlan_del``: bridge layer function invoked when a VLAN is removed from the
1001 - ``port_fdb_add``: bridge layer function invoked when the bridge wants to install a
1006 - ``port_fdb_del``: bridge layer function invoked when the bridge wants to remove a
1011 - ``port_fdb_dump``: bridge bypass function invoked by ``ndo_fdb_dump`` on the
1018 - ``port_mdb_add``: bridge layer function invoked when the bridge wants to install
1023 - ``port_mdb_del``: bridge layer function invoked when the bridge wants to remove a
1029 ----------------
1046 - ``port_lag_join``: function invoked when a given switch port is added to a
1047 LAG. The driver may return ``-EOPNOTSUPP``, and in this case, DSA will fall
1050 - ``port_lag_leave``: function invoked when a given switch port leaves a LAG
1052 - ``port_lag_change``: function invoked when the link state of any member of
1057 can optionally populate ``ds->num_lag_ids`` from the ``dsa_switch_ops::setup``
1061 IEC 62439-2 (MRP)
1062 -----------------
1064 The Media Redundancy Protocol is a topology management protocol optimized for
1065 fast fault recovery time for ring networks, which has some components
1071 PDUs might need to be terminated locally and others might need to be forwarded.
1077 necessary for the hardware, even if it is not MRP-aware, to be able to extract
1079 implementation. DSA today has no driver which is MRP-aware, therefore it only
1080 listens for the bare minimum switchdev objects required for the software assist
1083 - ``port_mrp_add`` and ``port_mrp_del``: notifies driver when an MRP instance
1086 - ``port_mrp_add_ring_role`` and ``port_mrp_del_ring_role``: function invoked
1091 IEC 62439-3 (HSR/PRP)
1092 ---------------------
1097 eliminating the duplicates at the receiver. The High-availability Seamless
1099 the redundant traffic are aware of the fact that it is HSR-tagged (because HSR
1101 ring topology. Both HSR and PRP use supervision frames for monitoring the
1102 health of the network and for discovery of other nodes.
1113 ``Documentation/networking/netdev-features.rst``. Additionally, the following
1116 - ``port_hsr_join``: function invoked when a given switch port is added to a
1117 DANP/DANH. The driver may return ``-EOPNOTSUPP`` and in this case, DSA will
1120 - ``port_hsr_leave``: function invoked when a given switch port leaves a
1127 -------------------------------------------------------------