The NXP NETC switch tag is a proprietary header added to frames after the
source MAC address. The switch tag has 3 types, and each type has 1 ~ 4
subtypes, the details are as follows.

Forward NXP switch tag (Type=0): Represents forwarded frames.
  - SubType = 0 - Normal frame processing.

To_Port NXP switch tag (Type=1): Represents frames that are to be sent
to a specific switch port.
  - SubType = 0. No request to perform timestamping.
  - SubType = 1. Request to perform one-step timestamping.
  - SubType = 2. Request to perform two-step timestamping.
  - SubType = 3. Request to perform both one-step timestamping and
    two-step timestamping.

To_Host NXP switch tag (Type=2): Represents frames redirected or copied
to the switch management port.
  - SubType = 0. Received frames redirected or copied to the switch
    management port.
  - SubType = 1. Received frames redirected or copied to the switch
    management port with captured timestamp at the switch port where
    the frame was received.
  - SubType = 2. Transmit timestamp response (two-step timestamping).

In addition, the length of different type switch tag is different, the
minimum length is 6 bytes, the maximum length is 14 bytes. Currently,
Forward tag, SubType 0 of To_Port tag and Subtype 0 of To_Host tag are
supported. More tags will be supported in the future.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20260518082506.1318236-10-wei.fang@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Add proprietary special tag format for the MaxLinear MXL862xx family of
switches. While using the same Ethertype as MaxLinear's GSW1xx switches,
the actual tag format differs significantly, hence we need a dedicated
tag driver for that.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/c64e6ddb6c93a4fac39f9ab9b2d8bf551a2b118d.1770433307.git.daniel@makrotopia.org
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Add support for a new DSA tagging protocol driver for the MaxLinear
GSW1xx switch family. The GSW1xx switches use a proprietary 8-byte
special tag inserted between the source MAC address and the EtherType
field to indicate the source and destination ports for frames
traversing the CPU port.

Implement the tag handling logic to insert the special tag on transmit
and parse it on receive.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://patch.msgid.link/0e973ebfd9433c30c96f50670da9e9449a0d98f2.1762170107.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add support for Motorcomm YT921x tags, which includes a proper
configurable ethertype field (default to 0x9988).

Signed-off-by: David Yang <mmyangfl@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20251017060859.326450-3-mmyangfl@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add support for legacy Broadcom FCS tags, which are similar to
DSA_TAG_PROTO_BRCM_LEGACY.
BCM5325 and BCM5365 switches require including the original FCS value and
length, as opposed to BCM63xx switches.
Adding the original FCS value and length to DSA_TAG_PROTO_BRCM_LEGACY would
impact performance of BCM63xx switches, so it's better to create a new tag.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250614080000.1884236-3-noltari@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This commit introduces a new tagger based on 802.1q tagging.
It's designed for the vsc73xx driver. The VSC73xx family doesn't have
any tag support for the RGMII port, but it could be based on VLANs.

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patch.msgid.link/20240713211620.1125910-8-paweldembicki@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Fix a minor typo in the help text for the NET_DSA_TAG_RTL4_A config
option.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Link: https://lore.kernel.org/r/20240607020843.1380735-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

There is no reason that I can see why the no-op tagging protocol should
be registered manually, so make it a module and make all drivers which
have any sort of reference to DSA_TAG_PROTO_NONE select it.

Note that I don't know if ksz_get_tag_protocol() really needs this,
or if it's just the logic which is poorly written. All switches seem to
have their own tagging protocol, and DSA_TAG_PROTO_NONE is just a
fallback that never gets used.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The Microchip LAN937X switches have a tagging protocol which is
very similar to KSZ tagging. So that the implementation is added to
tag_ksz.c and reused common APIs

Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The switch that is present on the Renesas RZ/N1 SoC uses a specific
VLAN value followed by 6 bytes which contains forwarding configuration.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>