devlink: implement line card provisioning

In order to be able to configure all needed stuff on a port/netdevice
of a line card without the line card being present, introduce line card
provisioning. Basically by setting a type, provisioning process will
start and driver is supposed to create a placeholder for instances
(ports/netdevices) for a line card type.

Allow the user to query the supported line card types over line card
get command. Then implement two netlink command SET to allow user to
set/unset the card type.

On the driver API side, add provision/unprovision ops and supported
types array to be advertised. Upon provision op call, the driver should
take care of creating the instances for the particular line card type.
Introduce provision_set/clear() functions to be called by the driver
once the provisioning/unprovisioning is done on its side. These helpers
are not to be called directly due to the async nature of provisioning.

Example:
$ devlink port # No ports are listed
$ devlink lc
pci/0000:01:00.0:
  lc 1 state unprovisioned
    supported_types:
       16x100G
  lc 2 state unprovisioned
    supported_types:
       16x100G
  lc 3 state unprovisioned
    supported_types:
       16x100G
  lc 4 state unprovisioned
    supported_types:
       16x100G
  lc 5 state unprovisioned
    supported_types:
       16x100G
  lc 6 state unprovisioned
    supported_types:
       16x100G
  lc 7 state unprovisioned
    supported_types:
       16x100G
  lc 8 state unprovisioned
    supported_types:
       16x100G

$ devlink lc set pci/0000:01:00.0 lc 8 type 16x100G
$ devlink lc show pci/0000:01:00.0 lc 8
pci/0000:01:00.0:
  lc 8 state active type 16x100G
    supported_types:
       16x100G
$ devlink port
pci/0000:01:00.0/0: type notset flavour cpu port 0 splittable false
pci/0000:01:00.0/53: type eth netdev enp1s0nl8p1 flavour physical lc 8 port 1 splittable true lanes 4
pci/0000:01:00.0/54: type eth netdev enp1s0nl8p2 flavour physical lc 8 port 2 splittable true lanes 4
pci/0000:01:00.0/55: type eth netdev enp1s0nl8p3 flavour physical lc 8 port 3 splittable true lanes 4
pci/0000:01:00.0/56: type eth netdev enp1s0nl8p4 flavour physical lc 8 port 4 splittable true lanes 4
pci/0000:01:00.0/57: type eth netdev enp1s0nl8p5 flavour physical lc 8 port 5 splittable true lanes 4
pci/0000:01:00.0/58: type eth netdev enp1s0nl8p6 flavour physical lc 8 port 6 splittable true lanes 4
pci/0000:01:00.0/59: type eth netdev enp1s0nl8p7 flavour physical lc 8 port 7 splittable true lanes 4
pci/0000:01:00.0/60: type eth netdev enp1s0nl8p8 flavour physical lc 8 port 8 splittable true lanes 4
pci/0000:01:00.0/61: type eth netdev enp1s0nl8p9 flavour physical lc 8 port 9 splittable true lanes 4
pci/0000:01:00.0/62: type eth netdev enp1s0nl8p10 flavour physical lc 8 port 10 splittable true lanes 4
pci/0000:01:00.0/63: type eth netdev enp1s0nl8p11 flavour physical lc 8 port 11 splittable true lanes 4
pci/0000:01:00.0/64: type eth netdev enp1s0nl8p12 flavour physical lc 8 port 12 splittable true lanes 4
pci/0000:01:00.0/125: type eth netdev enp1s0nl8p13 flavour physical lc 8 port 13 splittable true lanes 4
pci/0000:01:00.0/126: type eth netdev enp1s0nl8p14 flavour physical lc 8 port 14 splittable true lanes 4
pci/0000:01:00.0/127: type eth netdev enp1s0nl8p15 flavour physical lc 8 port 15 splittable true lanes 4
pci/0000:01:00.0/128: type eth netdev enp1s0nl8p16 flavour physical lc 8 port 16 splittable true lanes 4

$ devlink lc set pci/0000:01:00.0 lc 8 notype

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 122 insertions, 0 deletions

diff --git a/Documentation/networking/devlink/devlink-linecard.rst b/Documentation/networking/devlink/devlink-linecard.rst
new file mode 100644
index 000000000000..63ccd17f40ac
--- /dev/null
+++ b/Documentation/networking/devlink/devlink-linecard.rst
@@ -0,0 +1,121 @@
+.. 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.
+
+The following diagram provides a general overview of ``devlink-linecard``
+state transitions::
+
+                                          +-------------------------+
+                                          |                         |
+       +---------------------------------->      unprovisioned      |
+       |                                  |                         |
+       |                                  +--------|-------^--------+
+       |                                           |       |
+       |                                           |       |
+       |                                  +--------v-------|--------+
+       |                                  |                         |
+       |                                  |       provisioning      |
+       |                                  |                         |
+       |                                  +------------|------------+
+       |                                               |
+       |                 +-----------------------------+
+       |                 |                             |
+       |    +------------v------------+   +------------v------------+
+       |    |                         |   |                         |
+       +-----   provisioning_failed   |   |       provisioned       |
+       |    |                         |   |                         |
+       |    +------------^------------+   +------------|------------+
+       |                 |                             |
+       |                 |                             |
+       |                 |                +------------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
diff --git a/Documentation/networking/devlink/index.rst b/Documentation/networking/devlink/index.rst
index c17cdb079611..850715512293 100644
--- a/Documentation/networking/devlink/index.rst
+++ b/Documentation/networking/devlink/index.rst
@@ -39,6 +39,7 @@ general.
    devlink-resource
    devlink-reload
    devlink-trap
+   devlink-linecard
 
 Driver-specific documentation
 -----------------------------