Documentation: octeontx2: Add Documentation for RVU representors

Adds documentation for creating and configuring rvu port representors

Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Geetha sowjanya

Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst

@@ -14,6 +14,7 @@ Contents
 - `Basic packet flow`_
 - `Devlink health reporters`_
 - `Quality of service`_
+- `RVU representors`_
 
 Overview
 ========
@@ -340,3 +341,93 @@ Setup HTB offload
         # tc class add dev <interface> parent 1: classid 1:2 htb rate 10Gbit prio 2 quantum 188416
 
         # tc class add dev <interface> parent 1: classid 1:3 htb rate 10Gbit prio 2 quantum 32768
+
+
+RVU Representors
+================
+
+RVU representor driver adds support for creation of representor devices for
+RVU PFs' VFs in the system. Representor devices are created when user enables
+the switchdev mode.
+Switchdev mode can be enabled either before or after setting up SRIOV numVFs.
+All representor devices share a single NIXLF but each has a dedicated Rx/Tx
+queues. RVU PF representor driver registers a separate netdev for each
+Rx/Tx queue pair.
+
+Current HW does not support built-in switch which can do L2 learning and
+forwarding packets between representee and representor. Hence, packet path
+between representee and it's representor is achieved by setting up appropriate
+NPC MCAM filters.
+Transmit packets matching these filters will be loopbacked through hardware
+loopback channel/interface (i.e, instead of sending them out of MAC interface).
+Which will again match the installed filters and will be forwarded.
+This way representee => representor and representor => representee packet
+path is achieved. These rules get installed when representors are created
+and gets active/deactivate based on the representor/representee interface state.
+
+Usage example:
+
+ - Change device to switchdev mode::
+
+	# devlink dev eswitch set pci/0002:1c:00.0 mode switchdev
+
+ - List of representor devices on the system::
+
+	# ip link show
+	Rpf1vf0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000 link/ether f6:43:83:ee:26:21 brd ff:ff:ff:ff:ff:ff
+	Rpf1vf1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000 link/ether 12:b2:54:0e:24:54 brd ff:ff:ff:ff:ff:ff
+	Rpf1vf2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000 link/ether 4a:12:c4:4c:32:62 brd ff:ff:ff:ff:ff:ff
+	Rpf1vf3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000 link/ether ca:cb:68:0e:e2:6e brd ff:ff:ff:ff:ff:ff
+	Rpf2vf0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000 link/ether 06:cc:ad:b4:f0:93 brd ff:ff:ff:ff:ff:ff
+
+
+To delete the representors devices from the system. Change the device to legacy mode.
+
+ - Change device to legacy mode::
+
+	# devlink dev eswitch set pci/0002:1c:00.0 mode legacy
+
+RVU representors can be managed using devlink ports
+(see :ref:`Documentation/networking/devlink/devlink-port.rst <devlink_port>`) interface.
+
+ - Show devlink ports of representors::
+
+	# devlink port
+	pci/0002:1c:00.0/0: type eth netdev Rpf1vf0 flavour physical port 0 splittable false
+	pci/0002:1c:00.0/1: type eth netdev Rpf1vf1 flavour pcivf controller 0 pfnum 1 vfnum 1 external false splittable false
+	pci/0002:1c:00.0/2: type eth netdev Rpf1vf2 flavour pcivf controller 0 pfnum 1 vfnum 2 external false splittable false
+	pci/0002:1c:00.0/3: type eth netdev Rpf1vf3 flavour pcivf controller 0 pfnum 1 vfnum 3 external false splittable false
+
+Function attributes
+===================
+
+The RVU representor support function attributes for representors.
+Port function configuration of the representors are supported through devlink eswitch port.
+
+MAC address setup
+-----------------
+
+RVU representor driver support devlink port function attr mechanism to setup MAC
+address. (refer to Documentation/networking/devlink/devlink-port.rst)
+
+ - To setup MAC address for port 2::
+
+	# devlink port function set pci/0002:1c:00.0/2 hw_addr 5c:a1:1b:5e:43:11
+	# devlink port show pci/0002:1c:00.0/2
+	pci/0002:1c:00.0/2: type eth netdev Rpf1vf2 flavour pcivf controller 0 pfnum 1 vfnum 2 external false splittable false
+	function:
+		hw_addr 5c:a1:1b:5e:43:11
+
+
+TC offload
+==========
+
+The rvu representor driver implements support for offloading tc rules using port representors.
+
+ - Drop packets with vlan id 3::
+
+	# tc filter add dev Rpf1vf0 protocol 802.1Q parent ffff: flower vlan_id 3 vlan_ethtype ipv4 skip_sw action drop
+
+ - Redirect packets with vlan id 5 and IPv4 packets to eth1, after stripping vlan header.::
+
+	# tc filter add dev Rpf1vf0 ingress protocol 802.1Q flower vlan_id 5 vlan_ethtype ipv4 skip_sw action vlan pop action mirred ingress redirect dev eth1