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diff --git a/Documentation/networking/devlink/devlink-linecard.rst b/Documentation/networking/devlink/devlink-linecard.rst new file mode 100644 index 000000000..6c0b8928b --- /dev/null +++ b/Documentation/networking/devlink/devlink-linecard.rst @@ -0,0 +1,122 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Devlink Line card +================= + +Background +========== + +The ``devlink-linecard`` mechanism is targeted for manipulation of +line cards that serve as a detachable PHY modules for modular switch +system. Following operations are provided: + + * Get a list of supported line card types. + * Provision of a slot with specific line card type. + * Get and monitor of line card state and its change. + +Line card according to the type may contain one or more gearboxes +to mux the lanes with certain speed to multiple ports with lanes +of different speed. Line card ensures N:M mapping between +the switch ASIC modules and physical front panel ports. + +Overview +======== + +Each line card devlink object is created by device driver, +according to the physical line card slots available on the device. + +Similar to splitter cable, where the device might have no way +of detection of the splitter cable geometry, the device +might not have a way to detect line card type. For that devices, +concept of provisioning is introduced. It allows the user to: + + * Provision a line card slot with certain line card type + + - Device driver would instruct the ASIC to prepare all + resources accordingly. The device driver would + create all instances, namely devlink port and netdevices + that reside on the line card, according to the line card type + * Manipulate of line card entities even without line card + being physically connected or powered-up + * Setup splitter cable on line card ports + + - As on the ordinary ports, user may provision a splitter + cable of a certain type, without the need to + be physically connected to the port + * Configure devlink ports and netdevices + +Netdevice carrier is decided as follows: + + * Line card is not inserted or powered-down + + - The carrier is always down + * Line card is inserted and powered up + + - The carrier is decided as for ordinary port netdevice + +Line card state +=============== + +The ``devlink-linecard`` mechanism supports the following line card states: + + * ``unprovisioned``: Line card is not provisioned on the slot. + * ``unprovisioning``: Line card slot is currently being unprovisioned. + * ``provisioning``: Line card slot is currently in a process of being provisioned + with a line card type. + * ``provisioning_failed``: Provisioning was not successful. + * ``provisioned``: Line card slot is provisioned with a type. + * ``active``: Line card is powered-up and active. + +The following diagram provides a general overview of ``devlink-linecard`` +state transitions:: + + +-------------------------+ + | | + +----------------------------------> unprovisioned | + | | | + | +--------|-------^--------+ + | | | + | | | + | +--------v-------|--------+ + | | | + | | provisioning | + | | | + | +------------|------------+ + | | + | +-----------------------------+ + | | | + | +------------v------------+ +------------v------------+ +-------------------------+ + | | | | ----> | + +----- provisioning_failed | | provisioned | | active | + | | | | <---- | + | +------------^------------+ +------------|------------+ +-------------------------+ + | | | + | | | + | | +------------v------------+ + | | | | + | | | unprovisioning | + | | | | + | | +------------|------------+ + | | | + | +-----------------------------+ + | | + +-----------------------------------------------+ + + +Example usage +============= + +.. code:: shell + + $ devlink lc show [ DEV [ lc LC_INDEX ] ] + $ devlink lc set DEV lc LC_INDEX [ { type LC_TYPE | notype } ] + + # Show current line card configuration and status for all slots: + $ devlink lc + + # Set slot 8 to be provisioned with type "16x100G": + $ devlink lc set pci/0000:01:00.0 lc 8 type 16x100G + + # Set slot 8 to be unprovisioned: + $ devlink lc set pci/0000:01:00.0 lc 8 notype |