Documentation/networking/devlink/devlink-info.rst

   1 .. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2
   3 ============
   4 Devlink Info
   5 ============
   6
   7 The ``devlink-info`` mechanism enables device drivers to report device
   8 (hardware and firmware) information in a standard, extensible fashion.
   9
  10 The original motivation for the ``devlink-info`` API was twofold:
  11
  12  - making it possible to automate device and firmware management in a fleet
  13    of machines in a vendor-independent fashion (see also
  14    :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`);
  15  - name the per component FW versions (as opposed to the crowded ethtool
  16    version string).
  17
  18 ``devlink-info`` supports reporting multiple types of objects. Reporting driver
  19 versions is generally discouraged - here, and via any other Linux API.
  20
  21 .. list-table:: List of top level info objects
  22    :widths: 5 95
  23
  24    * - Name
  25      - Description
  26    * - ``driver``
  27      - Name of the currently used device driver, also available through sysfs.
  28
  29    * - ``serial_number``
  30      - Serial number of the device.
  31
  32        This is usually the serial number of the ASIC, also often available
  33        in PCI config space of the device in the *Device Serial Number*
  34        capability.
  35
  36        The serial number should be unique per physical device.
  37        Sometimes the serial number of the device is only 48 bits long (the
  38        length of the Ethernet MAC address), and since PCI DSN is 64 bits long
  39        devices pad or encode additional information into the serial number.
  40        One example is adding port ID or PCI interface ID in the extra two bytes.
  41        Drivers should make sure to strip or normalize any such padding
  42        or interface ID, and report only the part of the serial number
  43        which uniquely identifies the hardware. In other words serial number
  44        reported for two ports of the same device or on two hosts of
  45        a multi-host device should be identical.
  46
  47        .. note:: ``devlink-info`` API should be extended with a new field
  48           if devices want to report board/product serial number (often
  49           reported in PCI *Vital Product Data* capability).
  50
  51    * - ``fixed``
  52      - Group for hardware identifiers, and versions of components
  53        which are not field-updatable.
  54
  55        Versions in this section identify the device design. For example,
  56        component identifiers or the board version reported in the PCI VPD.
  57        Data in ``devlink-info`` should be broken into the smallest logical
  58        components, e.g. PCI VPD may concatenate various information
  59        to form the Part Number string, while in ``devlink-info`` all parts
  60        should be reported as separate items.
  61
  62        This group must not contain any frequently changing identifiers,
  63        such as serial numbers. See
  64        :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`
  65        to understand why.
  66
  67    * - ``running``
  68      - Group for information about currently running software/firmware.
  69        These versions often only update after a reboot, sometimes device reset.
  70
  71    * - ``stored``
  72      - Group for software/firmware versions in device flash.
  73
  74        Stored values must update to reflect changes in the flash even
  75        if reboot has not yet occurred. If device is not capable of updating
  76        ``stored`` versions when new software is flashed, it must not report
  77        them.
  78
  79 Each version can be reported at most once in each version group. Firmware
  80 components stored on the flash should feature in both the ``running`` and
  81 ``stored`` sections, if device is capable of reporting ``stored`` versions
  82 (see :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`).
  83 In case software/firmware components are loaded from the disk (e.g.
  84 ``/lib/firmware``) only the running version should be reported via
  85 the kernel API.
  86
  87 Generic Versions
  88 ================
  89
  90 It is expected that drivers use the following generic names for exporting
  91 version information. If a generic name for a given component doesn't exist yet,
  92 driver authors should consult existing driver-specific versions and attempt
  93 reuse. As last resort, if a component is truly unique, using driver-specific
  94 names is allowed, but these should be documented in the driver-specific file.
  95
  96 All versions should try to use the following terminology:
  97
  98 .. list-table:: List of common version suffixes
  99    :widths: 10 90
 100
 101    * - Name
 102      - Description
 103    * - ``id``, ``revision``
 104      - Identifiers of designs and revision, mostly used for hardware versions.
 105
 106    * - ``api``
 107      - Version of API between components. API items are usually of limited
 108        value to the user, and can be inferred from other versions by the vendor,
 109        so adding API versions is generally discouraged as noise.
 110
 111    * - ``bundle_id``
 112      - Identifier of a distribution package which was flashed onto the device.
 113        This is an attribute of a firmware package which covers multiple versions
 114        for ease of managing firmware images (see
 115        :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`).
 116
 117        ``bundle_id`` can appear in both ``running`` and ``stored`` versions,
 118        but it must not be reported if any of the components covered by the
 119        ``bundle_id`` was changed and no longer matches the version from
 120        the bundle.
 121
 122 board.id
 123 --------
 124
 125 Unique identifier of the board design.
 126
 127 board.rev
 128 ---------
 129
 130 Board design revision.
 131
 132 asic.id
 133 -------
 134
 135 ASIC design identifier.
 136
 137 asic.rev
 138 --------
 139
 140 ASIC design revision/stepping.
 141
 142 board.manufacture
 143 -----------------
 144
 145 An identifier of the company or the facility which produced the part.
 146
 147 fw
 148 --
 149
 150 Overall firmware version, often representing the collection of
 151 fw.mgmt, fw.app, etc.
 152
 153 fw.mgmt
 154 -------
 155
 156 Control unit firmware version. This firmware is responsible for house
 157 keeping tasks, PHY control etc. but not the packet-by-packet data path
 158 operation.
 159
 160 fw.app
 161 ------
 162
 163 Data path microcode controlling high-speed packet processing.
 164
 165 fw.undi
 166 -------
 167
 168 UNDI software, may include the UEFI driver, firmware or both.
 169
 170 fw.ncsi
 171 -------
 172
 173 Version of the software responsible for supporting/handling the
 174 Network Controller Sideband Interface.
 175
 176 fw.psid
 177 -------
 178
 179 Unique identifier of the firmware parameter set. These are usually
 180 parameters of a particular board, defined at manufacturing time.
 181
 182 fw.roce
 183 -------
 184
 185 RoCE firmware version which is responsible for handling roce
 186 management.
 187
 188 fw.bundle_id
 189 ------------
 190
 191 Unique identifier of the entire firmware bundle.
 192
 193 Future work
 194 ===========
 195
 196 The following extensions could be useful:
 197
 198  - product serial number - NIC boards often get labeled with a board serial
 199    number rather than ASIC serial number; it'd be useful to add board serial
 200    numbers to the API if they can be retrieved from the device;
 201
 202  - on-disk firmware file names - drivers list the file names of firmware they
 203    may need to load onto devices via the ``MODULE_FIRMWARE()`` macro. These,
 204    however, are per module, rather than per device. It'd be useful to list
 205    the names of firmware files the driver will try to load for a given device,
 206    in order of priority.