Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst

Source file repositories/reference/linux-study-clean/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst

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System: Linux kernel
Corpus path: Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst
Extension: .rst
Size: 7971 bytes
Lines: 195
Domain: Support Tooling And Documentation
Bucket: Documentation
Inferred role: Support Tooling And Documentation: documentation
Status: atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

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Annotated Snippet

.. SPDX-License-Identifier: GPL-2.0
.. include:: <isonum.txt>

=======================
DPAA2 MAC / PHY support
=======================

:Copyright: |copy| 2019 NXP

Overview
--------

The DPAA2 MAC / PHY support consists of a set of APIs that help DPAA2 network
drivers (dpaa2-eth, dpaa2-ethsw) interact with the PHY library.

DPAA2 Software Architecture
---------------------------

Among other DPAA2 objects, the fsl-mc bus exports DPNI objects (abstracting a
network interface) and DPMAC objects (abstracting a MAC). The dpaa2-eth driver
probes on the DPNI object and connects to and configures a DPMAC object with
the help of phylink.

Data connections may be established between a DPNI and a DPMAC, or between two
DPNIs. Depending on the connection type, the netif_carrier_[on/off] is handled
directly by the dpaa2-eth driver or by phylink.

.. code-block:: none

  Sources of abstracted link state information presented by the MC firmware

                                               +--------------------------------------+
  +------------+                  +---------+  |                           xgmac_mdio |
  | net_device |                  | phylink |--|  +-----+  +-----+  +-----+  +-----+  |
  +------------+                  +---------+  |  | PHY |  | PHY |  | PHY |  | PHY |  |
        |                             |        |  +-----+  +-----+  +-----+  +-----+  |
      +------------------------------------+   |                    External MDIO bus |
      |            dpaa2-eth               |   +--------------------------------------+
      +------------------------------------+
        |                             |                                           Linux
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        |                             |                                     MC firmware
        |              /|             V
  +----------+        / |       +----------+
  |          |       /  |       |          |
  |          |       |  |       |          |
  |   DPNI   |<------|  |<------|   DPMAC  |
  |          |       |  |       |          |
  |          |       \  |<---+  |          |
  +----------+        \ |    |  +----------+
                       \|    |
                             |
           +--------------------------------------+
           | MC firmware polling MAC PCS for link |
           |  +-----+  +-----+  +-----+  +-----+  |
           |  | PCS |  | PCS |  | PCS |  | PCS |  |
           |  +-----+  +-----+  +-----+  +-----+  |
           |                    Internal MDIO bus |
           +--------------------------------------+


Depending on an MC firmware configuration setting, each MAC may be in one of two modes:

- DPMAC_LINK_TYPE_FIXED: the link state management is handled exclusively by
  the MC firmware by polling the MAC PCS. Without the need to register a
  phylink instance, the dpaa2-eth driver will not bind to the connected dpmac
  object at all.

- DPMAC_LINK_TYPE_PHY: The MC firmware is left waiting for link state update
  events, but those are in fact passed strictly between the dpaa2-mac (based on

Annotation

Atlas domain: Support Tooling And Documentation / Documentation.
Implementation status: atlas-only.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.