Crate ieee802_3_miim 

IEEE 802.3 Media Independent Interface Management

A crate traits for accessing the Media Independent Interface Management on IEEE 802.3 PHYs.

What is Media Independent Interface Management?

The MIIM (Media Independent Interface Management) Interface is a part of the IEEE 802.3 standard used to manage the state of PHYs.

In it’s most cut-down form, it provides basic configuration and status access. Extended features (implemented by most PHYs) include autonegotiation configuration, custom on-chip register access through MMD, and extended status information.

What is MDIO?

MDIO (Management Data Input/Output) is one of the standard-mandated method of accessing MIIM functions. Most PHYs support this protocol for accessing their MIIM interface, so the crate provides a default PHY implementation (MdioPhy) that will let you access your PHYs over an MDIO bus. However: some PHYs (such as the Microchip KSZ8863) also provide access to MIIM registers over other interfaces. Therefore, the MIIM functionality provided by this crate is not tightly coupled to access using MDIO.

Getting started

There are several ways to get started, depending on what your goal with the crate is.

Application authors

The core trait, Miim, provides the functionality most users want: the speed of the PHY as reported by its registers (through Miim::get_link_state), and link status. Since the trait is a trait, you’ll need an implementation of Miim to actually communicate with your PHY. This implementation is generally provided by your HAL, either as a direct implementation of Miim, or as an implementation of Mdio, which can be used directly with an MdioPhy.

If the HAL you are using does not support this crate directly, implementing the Miim trait on a wrapper type is likely a decent alternative: the trait has few required functions, and provides a lot of functionality on top of them.

HAL authors

HALs can provide the following:

• If your device supports MDIO, provide an implementation of the Mdio trait. All other functionality (Miim, MdioPhy) will be available to your users based on it.
• If your device can provide access to MIIM registers in some other way (i.e. to only a single, specific PHY address on an MDIO bus), provide an implemetation of Miim directly.

PHY driver authors

PHY drivers should, in general, aim to use an instance of Miim to perform their operations. See the example implemetations in the phy module for how to use it.

Additionally, it is recommended that you implement Miim for your PHY itself, delegating to the Miim implementation that it owns: this way, all functionality provided by the trait will be available to users of your driver, practically for free. Make sure to also re-export the trait from your crate if you choose to do this.

Non-generic PHYs

This crate also provides some PHY implementations (ieee802_3_miim::phy), containing specialized functionality for those PHYs:

• Interrupt configuration through vendor-specific MIIM registers (lan87xxa, ksz8081r)
• Custom PHY initialization sequences (lan87xxa)
• Custom speed detection implementation for fixed-function PHYs (lan8770)

However, these PHYs also implement Miim, so if your code is generic over an impl Miim, you can swap them however you see fit.

More custom PHY implementations are always welcome :)

License

This project is licensed under the MIT license.

See LICENSE for more information.

Modules

mdio

This module defines traits and structs used for accessing MIIM over MDIO.

mmd

MDIO Manageable Device (MMD, Clause 45) access for MIIM PHYs.

phy

Implementations of MIIM for existing PHYs

registers

MIIM register definitions.

Structs

GetLinkStateProcess

A state machine describing the process of determining the link state of an (R)(G)MII PHY.

LinkState

The state of an link (R)(G)MII link.

PhyIdent

The PHY IDENT of a Miim.

RegisterAddress

A MIIM register address.

Enums

LinkSpeed

All link speeds that may be supported by a normal (R)(G)MII PHY.

LinkStateError

Errors that can occur when attempting to determine the state of a link.

Traits

Miim

An IEEE 802.3 compatible PHY that can be managed using the Media Independent Interface Management (MIIM) Interface.