0001 .. SPDX-License-Identifier: GPL-2.0
0002
0003 =================
0004 Devlink Line card
0005 =================
0006
0007 Background
0008 ==========
0009
0010 The ``devlink-linecard`` mechanism is targeted for manipulation of
0011 line cards that serve as a detachable PHY modules for modular switch
0012 system. Following operations are provided:
0013
0014 * Get a list of supported line card types.
0015 * Provision of a slot with specific line card type.
0016 * Get and monitor of line card state and its change.
0017
0018 Line card according to the type may contain one or more gearboxes
0019 to mux the lanes with certain speed to multiple ports with lanes
0020 of different speed. Line card ensures N:M mapping between
0021 the switch ASIC modules and physical front panel ports.
0022
0023 Overview
0024 ========
0025
0026 Each line card devlink object is created by device driver,
0027 according to the physical line card slots available on the device.
0028
0029 Similar to splitter cable, where the device might have no way
0030 of detection of the splitter cable geometry, the device
0031 might not have a way to detect line card type. For that devices,
0032 concept of provisioning is introduced. It allows the user to:
0033
0034 * Provision a line card slot with certain line card type
0035
0036 - Device driver would instruct the ASIC to prepare all
0037 resources accordingly. The device driver would
0038 create all instances, namely devlink port and netdevices
0039 that reside on the line card, according to the line card type
0040 * Manipulate of line card entities even without line card
0041 being physically connected or powered-up
0042 * Setup splitter cable on line card ports
0043
0044 - As on the ordinary ports, user may provision a splitter
0045 cable of a certain type, without the need to
0046 be physically connected to the port
0047 * Configure devlink ports and netdevices
0048
0049 Netdevice carrier is decided as follows:
0050
0051 * Line card is not inserted or powered-down
0052
0053 - The carrier is always down
0054 * Line card is inserted and powered up
0055
0056 - The carrier is decided as for ordinary port netdevice
0057
0058 Line card state
0059 ===============
0060
0061 The ``devlink-linecard`` mechanism supports the following line card states:
0062
0063 * ``unprovisioned``: Line card is not provisioned on the slot.
0064 * ``unprovisioning``: Line card slot is currently being unprovisioned.
0065 * ``provisioning``: Line card slot is currently in a process of being provisioned
0066 with a line card type.
0067 * ``provisioning_failed``: Provisioning was not successful.
0068 * ``provisioned``: Line card slot is provisioned with a type.
0069 * ``active``: Line card is powered-up and active.
0070
0071 The following diagram provides a general overview of ``devlink-linecard``
0072 state transitions::
0073
0074 +-------------------------+
0075 | |
0076 +----------------------------------> unprovisioned |
0077 | | |
0078 | +--------|-------^--------+
0079 | | |
0080 | | |
0081 | +--------v-------|--------+
0082 | | |
0083 | | provisioning |
0084 | | |
0085 | +------------|------------+
0086 | |
0087 | +-----------------------------+
0088 | | |
0089 | +------------v------------+ +------------v------------+ +-------------------------+
0090 | | | | ----> |
0091 +----- provisioning_failed | | provisioned | | active |
0092 | | | | <---- |
0093 | +------------^------------+ +------------|------------+ +-------------------------+
0094 | | |
0095 | | |
0096 | | +------------v------------+
0097 | | | |
0098 | | | unprovisioning |
0099 | | | |
0100 | | +------------|------------+
0101 | | |
0102 | +-----------------------------+
0103 | |
0104 +-----------------------------------------------+
0105
0106
0107 Example usage
0108 =============
0109
0110 .. code:: shell
0111
0112 $ devlink lc show [ DEV [ lc LC_INDEX ] ]
0113 $ devlink lc set DEV lc LC_INDEX [ { type LC_TYPE | notype } ]
0114
0115 # Show current line card configuration and status for all slots:
0116 $ devlink lc
0117
0118 # Set slot 8 to be provisioned with type "16x100G":
0119 $ devlink lc set pci/0000:01:00.0 lc 8 type 16x100G
0120
0121 # Set slot 8 to be unprovisioned:
0122 $ devlink lc set pci/0000:01:00.0 lc 8 notype
