.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) ============Devlink Info============ The ``devlink-info`` mechanism enables device drivers to report device(hardware and firmware) information in a standard, extensible fashion. The original motivation for the ``devlink-info`` API was twofold:  - making it possible to automate device and firmware management in a fleet   of machines in a vendor-independent fashion (see also   :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`); - name the per component FW versions (as opposed to the crowded ethtool   version string). ``devlink-info`` supports reporting multiple types of objects. Reporting driverversions is generally discouraged - here, and via any other Linux API. .. list-table:: List of top level info objects   :widths: 5 95    * - Name     - Description   * - ``driver``     - Name of the currently used device driver, also available through sysfs.    * - ``serial_number``     - Serial number of the device.        This is usually the serial number of the ASIC, also often available       in PCI config space of the device in the *Device Serial Number*       capability.        The serial number should be unique per physical device.       Sometimes the serial number of the device is only 48 bits long (the       length of the Ethernet MAC address), and since PCI DSN is 64 bits long       devices pad or encode additional information into the serial number.       One example is adding port ID or PCI interface ID in the extra two bytes.       Drivers should make sure to strip or normalize any such padding       or interface ID, and report only the part of the serial number       which uniquely identifies the hardware. In other words serial number       reported for two ports of the same device or on two hosts of       a multi-host device should be identical.    * - ``board.serial_number``     - Board serial number of the device.        This is usually the serial number of the board, often available in       PCI *Vital Product Data*.    * - ``fixed``     - Group for hardware identifiers, and versions of components       which are not field-updatable.        Versions in this section identify the device design. For example,       component identifiers or the board version reported in the PCI VPD.       Data in ``devlink-info`` should be broken into the smallest logical       components, e.g. PCI VPD may concatenate various information       to form the Part Number string, while in ``devlink-info`` all parts       should be reported as separate items.        This group must not contain any frequently changing identifiers,       such as serial numbers. See       :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`       to understand why.    * - ``running``     - Group for information about currently running software/firmware.       These versions often only update after a reboot, sometimes device reset.    * - ``stored``     - Group for software/firmware versions in device flash.        Stored values must update to reflect changes in the flash even       if reboot has not yet occurred. If device is not capable of updating       ``stored`` versions when new software is flashed, it must not report       them. Each version can be reported at most once in each version group. Firmwarecomponents stored on the flash should feature in both the ``running`` and``stored`` sections, if device is capable of reporting ``stored`` versions(see :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`).In case software/firmware components are loaded from the disk (e.g.``/lib/firmware``) only the running version should be reported viathe kernel API. Please note that any security versions reported via devlink are purelyinformational. Devlink does not use a secure channel to communicate withthe device. Generic Versions================ It is expected that drivers use the following generic names for exportingversion information. If a generic name for a given component doesn't exist yet,driver authors should consult existing driver-specific versions and attemptreuse. As last resort, if a component is truly unique, using driver-specificnames is allowed, but these should be documented in the driver-specific file. All versions should try to use the following terminology: .. list-table:: List of common version suffixes   :widths: 10 90    * - Name     - Description   * - ``id``, ``revision``     - Identifiers of designs and revision, mostly used for hardware versions.    * - ``api``     - Version of API between components. API items are usually of limited       value to the user, and can be inferred from other versions by the vendor,       so adding API versions is generally discouraged as noise.    * - ``bundle_id``     - Identifier of a distribution package which was flashed onto the device.       This is an attribute of a firmware package which covers multiple versions       for ease of managing firmware images (see       :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`).        ``bundle_id`` can appear in both ``running`` and ``stored`` versions,       but it must not be reported if any of the components covered by the       ``bundle_id`` was changed and no longer matches the version from       the bundle. board.id-------- Unique identifier of the board design. board.rev--------- Board design revision. asic.id------- ASIC design identifier. asic.rev-------- ASIC design revision/stepping. board.manufacture----------------- An identifier of the company or the facility which produced the part. board.part_number----------------- Part number of the board and its components. fw-- Overall firmware version, often representing the collection offw.mgmt, fw.app, etc. fw.mgmt------- Control unit firmware version. This firmware is responsible for housekeeping tasks, PHY control etc. but not the packet-by-packet data pathoperation. fw.mgmt.api----------- Firmware interface specification version of the software interfaces betweendriver and firmware. fw.app------ Data path microcode controlling high-speed packet processing. fw.undi------- UNDI software, may include the UEFI driver, firmware or both. fw.ncsi------- Version of the software responsible for supporting/handling theNetwork Controller Sideband Interface. fw.psid------- Unique identifier of the firmware parameter set. These are usuallyparameters of a particular board, defined at manufacturing time. fw.roce------- RoCE firmware version which is responsible for handling rocemanagement. fw.bundle_id------------ Unique identifier of the entire firmware bundle. fw.bootloader------------- Version of the bootloader. Future work=========== The following extensions could be useful:  - on-disk firmware file names - drivers list the file names of firmware they   may need to load onto devices via the ``MODULE_FIRMWARE()`` macro. These,   however, are per module, rather than per device. It'd be useful to list   the names of firmware files the driver will try to load for a given device,   in order of priority.