1.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2
3============
4Devlink Info
5============
6
7The ``devlink-info`` mechanism enables device drivers to report device
8(hardware and firmware) information in a standard, extensible fashion.
9
10The 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
19versions 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   * - ``board.serial_number``
48     - Board serial number of the device.
49
50       This is usually the serial number of the board, often available in
51       PCI *Vital Product Data*.
52
53   * - ``fixed``
54     - Group for hardware identifiers, and versions of components
55       which are not field-updatable.
56
57       Versions in this section identify the device design. For example,
58       component identifiers or the board version reported in the PCI VPD.
59       Data in ``devlink-info`` should be broken into the smallest logical
60       components, e.g. PCI VPD may concatenate various information
61       to form the Part Number string, while in ``devlink-info`` all parts
62       should be reported as separate items.
63
64       This group must not contain any frequently changing identifiers,
65       such as serial numbers. See
66       :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`
67       to understand why.
68
69   * - ``running``
70     - Group for information about currently running software/firmware.
71       These versions often only update after a reboot, sometimes device reset.
72
73   * - ``stored``
74     - Group for software/firmware versions in device flash.
75
76       Stored values must update to reflect changes in the flash even
77       if reboot has not yet occurred. If device is not capable of updating
78       ``stored`` versions when new software is flashed, it must not report
79       them.
80
81Each version can be reported at most once in each version group. Firmware
82components stored on the flash should feature in both the ``running`` and
83``stored`` sections, if device is capable of reporting ``stored`` versions
84(see :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`).
85In case software/firmware components are loaded from the disk (e.g.
86``/lib/firmware``) only the running version should be reported via
87the kernel API.
88
89Please note that any security versions reported via devlink are purely
90informational. Devlink does not use a secure channel to communicate with
91the device.
92
93Generic Versions
94================
95
96It is expected that drivers use the following generic names for exporting
97version information. If a generic name for a given component doesn't exist yet,
98driver authors should consult existing driver-specific versions and attempt
99reuse. As last resort, if a component is truly unique, using driver-specific
100names is allowed, but these should be documented in the driver-specific file.
101
102All versions should try to use the following terminology:
103
104.. list-table:: List of common version suffixes
105   :widths: 10 90
106
107   * - Name
108     - Description
109   * - ``id``, ``revision``
110     - Identifiers of designs and revision, mostly used for hardware versions.
111
112   * - ``api``
113     - Version of API between components. API items are usually of limited
114       value to the user, and can be inferred from other versions by the vendor,
115       so adding API versions is generally discouraged as noise.
116
117   * - ``bundle_id``
118     - Identifier of a distribution package which was flashed onto the device.
119       This is an attribute of a firmware package which covers multiple versions
120       for ease of managing firmware images (see
121       :ref:`Documentation/networking/devlink/devlink-flash.rst <devlink_flash>`).
122
123       ``bundle_id`` can appear in both ``running`` and ``stored`` versions,
124       but it must not be reported if any of the components covered by the
125       ``bundle_id`` was changed and no longer matches the version from
126       the bundle.
127
128board.id
129--------
130
131Unique identifier of the board design.
132
133board.rev
134---------
135
136Board design revision.
137
138asic.id
139-------
140
141ASIC design identifier.
142
143asic.rev
144--------
145
146ASIC design revision/stepping.
147
148board.manufacture
149-----------------
150
151An identifier of the company or the facility which produced the part.
152
153board.part_number
154-----------------
155
156Part number of the board and its components.
157
158fw
159--
160
161Overall firmware version, often representing the collection of
162fw.mgmt, fw.app, etc.
163
164fw.mgmt
165-------
166
167Control unit firmware version. This firmware is responsible for house
168keeping tasks, PHY control etc. but not the packet-by-packet data path
169operation.
170
171fw.mgmt.api
172-----------
173
174Firmware interface specification version of the software interfaces between
175driver and firmware.
176
177fw.app
178------
179
180Data path microcode controlling high-speed packet processing.
181
182fw.undi
183-------
184
185UNDI software, may include the UEFI driver, firmware or both.
186
187fw.ncsi
188-------
189
190Version of the software responsible for supporting/handling the
191Network Controller Sideband Interface.
192
193fw.psid
194-------
195
196Unique identifier of the firmware parameter set. These are usually
197parameters of a particular board, defined at manufacturing time.
198
199fw.roce
200-------
201
202RoCE firmware version which is responsible for handling roce
203management.
204
205fw.bundle_id
206------------
207
208Unique identifier of the entire firmware bundle.
209
210fw.bootloader
211-------------
212
213Version of the bootloader.
214
215Future work
216===========
217
218The following extensions could be useful:
219
220 - on-disk firmware file names - drivers list the file names of firmware they
221   may need to load onto devices via the ``MODULE_FIRMWARE()`` macro. These,
222   however, are per module, rather than per device. It'd be useful to list
223   the names of firmware files the driver will try to load for a given device,
224   in order of priority.
225