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| 1 | +.. SPDX-License-Identifier: GPL-2.0 |
| 2 | +
|
| 3 | +================= |
| 4 | +Devlink Line card |
| 5 | +================= |
| 6 | + |
| 7 | +Background |
| 8 | +========== |
| 9 | + |
| 10 | +The ``devlink-linecard`` mechanism is targeted for manipulation of |
| 11 | +line cards that serve as a detachable PHY modules for modular switch |
| 12 | +system. Following operations are provided: |
| 13 | + |
| 14 | + * Get a list of supported line card types. |
| 15 | + * Provision of a slot with specific line card type. |
| 16 | + * Get and monitor of line card state and its change. |
| 17 | + |
| 18 | +Line card according to the type may contain one or more gearboxes |
| 19 | +to mux the lanes with certain speed to multiple ports with lanes |
| 20 | +of different speed. Line card ensures N:M mapping between |
| 21 | +the switch ASIC modules and physical front panel ports. |
| 22 | + |
| 23 | +Overview |
| 24 | +======== |
| 25 | + |
| 26 | +Each line card devlink object is created by device driver, |
| 27 | +according to the physical line card slots available on the device. |
| 28 | + |
| 29 | +Similar to splitter cable, where the device might have no way |
| 30 | +of detection of the splitter cable geometry, the device |
| 31 | +might not have a way to detect line card type. For that devices, |
| 32 | +concept of provisioning is introduced. It allows the user to: |
| 33 | + |
| 34 | + * Provision a line card slot with certain line card type |
| 35 | + |
| 36 | + - Device driver would instruct the ASIC to prepare all |
| 37 | + resources accordingly. The device driver would |
| 38 | + create all instances, namely devlink port and netdevices |
| 39 | + that reside on the line card, according to the line card type |
| 40 | + * Manipulate of line card entities even without line card |
| 41 | + being physically connected or powered-up |
| 42 | + * Setup splitter cable on line card ports |
| 43 | + |
| 44 | + - As on the ordinary ports, user may provision a splitter |
| 45 | + cable of a certain type, without the need to |
| 46 | + be physically connected to the port |
| 47 | + * Configure devlink ports and netdevices |
| 48 | + |
| 49 | +Netdevice carrier is decided as follows: |
| 50 | + |
| 51 | + * Line card is not inserted or powered-down |
| 52 | + |
| 53 | + - The carrier is always down |
| 54 | + * Line card is inserted and powered up |
| 55 | + |
| 56 | + - The carrier is decided as for ordinary port netdevice |
| 57 | + |
| 58 | +Line card state |
| 59 | +=============== |
| 60 | + |
| 61 | +The ``devlink-linecard`` mechanism supports the following line card states: |
| 62 | + |
| 63 | + * ``unprovisioned``: Line card is not provisioned on the slot. |
| 64 | + * ``unprovisioning``: Line card slot is currently being unprovisioned. |
| 65 | + * ``provisioning``: Line card slot is currently in a process of being provisioned |
| 66 | + with a line card type. |
| 67 | + * ``provisioning_failed``: Provisioning was not successful. |
| 68 | + * ``provisioned``: Line card slot is provisioned with a type. |
| 69 | + |
| 70 | +The following diagram provides a general overview of ``devlink-linecard`` |
| 71 | +state transitions:: |
| 72 | + |
| 73 | + +-------------------------+ |
| 74 | + | | |
| 75 | + +----------------------------------> unprovisioned | |
| 76 | + | | | |
| 77 | + | +--------|-------^--------+ |
| 78 | + | | | |
| 79 | + | | | |
| 80 | + | +--------v-------|--------+ |
| 81 | + | | | |
| 82 | + | | provisioning | |
| 83 | + | | | |
| 84 | + | +------------|------------+ |
| 85 | + | | |
| 86 | + | +-----------------------------+ |
| 87 | + | | | |
| 88 | + | +------------v------------+ +------------v------------+ |
| 89 | + | | | | | |
| 90 | + +----- provisioning_failed | | provisioned | |
| 91 | + | | | | | |
| 92 | + | +------------^------------+ +------------|------------+ |
| 93 | + | | | |
| 94 | + | | | |
| 95 | + | | +------------v------------+ |
| 96 | + | | | | |
| 97 | + | | | unprovisioning | |
| 98 | + | | | | |
| 99 | + | | +------------|------------+ |
| 100 | + | | | |
| 101 | + | +-----------------------------+ |
| 102 | + | | |
| 103 | + +-----------------------------------------------+ |
| 104 | + |
| 105 | + |
| 106 | +Example usage |
| 107 | +============= |
| 108 | + |
| 109 | +.. code:: shell |
| 110 | +
|
| 111 | + $ devlink lc show [ DEV [ lc LC_INDEX ] ] |
| 112 | + $ devlink lc set DEV lc LC_INDEX [ { type LC_TYPE | notype } ] |
| 113 | +
|
| 114 | + # Show current line card configuration and status for all slots: |
| 115 | + $ devlink lc |
| 116 | +
|
| 117 | + # Set slot 8 to be provisioned with type "16x100G": |
| 118 | + $ devlink lc set pci/0000:01:00.0 lc 8 type 16x100G |
| 119 | +
|
| 120 | + # Set slot 8 to be unprovisioned: |
| 121 | + $ devlink lc set pci/0000:01:00.0 lc 8 notype |
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