staging: fsl-dpaa2/ethsw: Add README

DPAA2 Ethernet Switch driver

============================

This file provides documentation for the DPAA2 Ethernet Switch driver

Contents

========

	Supported Platforms

	Architecture Overview

	Creating an Ethernet Switch

	Features

	Supported Platforms

===================

This driver provides networking support for Freescale LS2085A, LS2088A

DPAA2 SoCs.

Architecture Overview

=====================

The Ethernet Switch in the DPAA2 architecture consists of several hardware

resources that provide the functionality. These are allocated and

configured via the Management Complex (MC) portals. MC abstracts most of

these resources as DPAA2 objects and exposes ABIs through which they can

be configured and controlled.

For a more detailed description of the DPAA2 architecture and its object

abstractions see:

	drivers/staging/fsl-mc/README.txt

The Ethernet Switch is built on top of a Datapath Switch (DPSW) object.

Configuration interface:

          ---------------------

         | DPAA2 Switch driver |

          ---------------------

                   .

                   .

              ----------

             | DPSW API |

              ----------

                   .           software

 ================= . ==============

                   .           hardware

          ---------------------

         | MC hardware portals |

          ---------------------

                   .

                   .

                 ------

                | DPSW |

                 ------

Driver uses the switch device driver model and exposes each switch port as

a network interface, which can be included in a bridge. Traffic switched

between ports is offloaded into the hardware. Exposed network interfaces

are not used for I/O, they are used just for configuration. This

limitation is going to be addressed in the future.

The DPSW can have ports connected to DPNIs or to PHYs via DPMACs.

 [ethA]     [ethB]     [ethC]     [ethD]     [ethE]     [ethF]

    :          :          :          :          :          :

    :          :          :          :          :          :

[eth drv]  [eth drv]  [                ethsw drv              ]

    :          :          :          :          :          :        kernel

========================================================================

    :          :          :          :          :          :        hardware

 [DPNI]      [DPNI]     [============= DPSW =================]

    |          |          |          |          |          |

    |           ----------           |       [DPMAC]    [DPMAC]

     -------------------------------            |          |

                                                |          |

                                              [PHY]      [PHY]

For a more detailed description of the Ethernet switch device driver model

see:

	Documentation/networking/switchdev.txt

Creating an Ethernet Switch

===========================

A device is created for the switch objects probed on the MC bus. Each DPSW

has a number of properties which determine the configuration options and

associated hardware resources.

A DPSW object (and the other DPAA2 objects needed for a DPAA2 switch) can

be added to a container on the MC bus in one of two ways: statically,

through a Datapath Layout Binary file (DPL) that is parsed by MC at boot

time; or created dynamically at runtime, via the DPAA2 objects APIs.

Features

========

Driver configures DPSW to perform hardware switching offload of

unicast/multicast/broadcast (VLAN tagged or untagged) traffic between its

ports.

It allows configuration of hardware learning, flooding, multicast groups,

port VLAN configuration and STP state.

Static entries can be added/removed from the FDB.

Hardware statistics for each port are provided through ethtool -S option.