feat(linux): Update CPSW documentation to enable switch mode

Update documentation for enabling CPSW in switch mode for AM57x devices.

Signed-off-by: Aksh Garg <[email protected]>

Author: AkshGarg-19

source/linux/Foundational_Components/Kernel/Kernel_Drivers/Network/CPSW.rst

@@ -249,7 +249,7 @@ VLAN will be subscribed to host port and the respective slave ports.
 
    < or >
 
-   vconfig rem eth0 5
+   vconfig rem eth0.5
 
 **IP assigning**
 
@@ -417,7 +417,7 @@ To allow Dual Emac interfaces to be added to the Linux Bridge one of following c
 Dual EMAC can be enabled with adding the entry dual\_emac to the cpsw
 device tree node as the reference patch below
 
-.. code:: dts
+.. code:: diff
 
     diff --git a/arch/arm/boot/dts/am335x-evmsk.dts b/arch/arm/boot/dts/am335x-evmsk.dts
     index ac1f759..b50e9ef 100644
@@ -571,6 +571,59 @@ Userspace binary formats --->
 
 |
 
+.. rubric:: Multi port Switch mode
+   :name: multi-port-switch-mode
+
+.. note::
+
+   This section documents the Switch mode features available with
+   CPSW.
+
+The Switch mode can be enabled by configuring devlink driver parameter
+"switch_mode" to true
+
+.. code-block:: console
+
+   devlink dev param set platform/48484000.switch name switch_mode value true cmode runtime
+
+Above setting can be done regardless of the state of Port's netdev
+devices - UP/DOWN, but Port's netdev devices have to be in UP state
+before joining the bridge. This is to avoid overwriting of bridge
+configuration as CPSW switch driver completely reloads its configuration
+when first port changes its state to UP.
+
+When all the interfaces have joined the bridge - CPSW switch driver will
+enable marking packets with offload_fwd_mark flag.
+
+All configuration is implemented via switchdev API.
+
+.. rubric:: Bridge Setup
+   :name: bridge-setup
+
+.. code-block:: console
+
+   devlink dev param set platform/48484000.switch name switch_mode value true cmode runtime
+
+   ip link add name br0 type bridge
+   ip link set dev br0 type bridge ageing_time 1000
+   ip link set dev eth0 up
+   ip link set dev eth1 up
+   ip link set dev eth0 master br0
+   ip link set dev eth1 master br0
+
+   [*] bridge vlan add dev br0 vid 1 self
+   [*] bridge vlan add dev br0 vid 1 pvid untagged self
+   [*] if vlan_filtering=1, where default_pvid=1
+
+   Note: Steps [*] are mandatory.
+
+.. rubric:: Turn On/Off Spanning Tree Protocol (STP)
+   :name: turn-on/off-spanning-tree-protocol
+
+.. code-block:: console
+
+   ip link set dev br0 type bridge stp_state 1/0
+
 .. rubric:: Switch Config Commands
    :name: switch-config-commands