[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20201205122717.76d193a2@kicinski-fedora-pc1c0hjn.DHCP.thefacebook.com>
Date: Sat, 5 Dec 2020 12:27:17 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Parav Pandit <parav@...dia.com>
Cc: <netdev@...r.kernel.org>, <davem@...emloft.net>,
<jacob.e.keller@...el.com>, Jiri Pirko <jiri@...dia.com>
Subject: Re: [PATCH net-next v4] devlink: Add devlink port documentation
On Thu, 3 Dec 2020 20:02:55 +0200 Parav Pandit wrote:
> Added documentation for devlink port and port function related commands.
>
> Signed-off-by: Parav Pandit <parav@...dia.com>
> Reviewed-by: Jiri Pirko <jiri@...dia.com>
> Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>
> +============
> +Devlink Port
> +============
> +
> +``devlink-port`` is a port that exists on the device.
Can we add something like:
Each port is a logically separate ingress/egress point of the device.
?
> A devlink port can
> +be of one among many flavours. A devlink port flavour along with port
> +attributes describe what a port represents.
> +
> +A device driver that intends to publish a devlink port sets the
> +devlink port attributes and registers the devlink port.
> +
> +Devlink port flavours are described below.
> +
> +.. list-table:: List of devlink port flavours
> + :widths: 33 90
> +
> + * - Flavour
> + - Description
> + * - ``DEVLINK_PORT_FLAVOUR_PHYSICAL``
> + - Any kind of physical networking port. This can be an eswitch physical
> + port or any other physical port on the device.
> + * - ``DEVLINK_PORT_FLAVOUR_DSA``
> + - This indicates a DSA interconnect port.
> + * - ``DEVLINK_PORT_FLAVOUR_CPU``
> + - This indicates a CPU port applicable only to DSA.
> + * - ``DEVLINK_PORT_FLAVOUR_PCI_PF``
> + - This indicates an eswitch port representing a networking port of
> + PCI physical function (PF).
> + * - ``DEVLINK_PORT_FLAVOUR_PCI_VF``
> + - This indicates an eswitch port representing a networking port of
> + PCI virtual function (VF).
> + * - ``DEVLINK_PORT_FLAVOUR_VIRTUAL``
> + - This indicates a virtual port for the virtual PCI device such as PCI VF.
> +
> +Devlink port types are described below.
How about:
Physical ports can have different types based on the link layer:
> +.. list-table:: List of devlink port types
> + :widths: 23 90
> +
> + * - Type
> + - Description
> + * - ``DEVLINK_PORT_TYPE_ETH``
> + - Driver should set this port type when a link layer of the port is Ethernet.
> + * - ``DEVLINK_PORT_TYPE_IB``
> + - Driver should set this port type when a link layer of the port is InfiniBand.
Please wrap at 80 chars.
> + * - ``DEVLINK_PORT_TYPE_AUTO``
> + - This type is indicated by the user when user prefers to set the port type
> + to be automatically detected by the device driver.
How about:
This type is indicated by the user when driver should detect the port
type automatically.
> +A controller consists of one or more PCI functions.
This need some intro. Like:
PCI controllers
---------------
In most cases PCI devices will have only one controller, with
potentially multiple physical and virtual functions. Devices connected
to multiple CPUs and SmartNICs, however, may have multiple controllers.
> Such PCI function consists
> +of one or more networking ports.
PCI function consists of networking ports? What do you mean by
a networking port? All devlink ports are networking ports.
> A networking port of such PCI function is
> +represented by the eswitch devlink port.
What's eswitch devlink port? It was never defined.
> A devlink instance holds ports of two
> +types of controllers.
For devices with multiple controllers we can distinguish...
> +(1) controller discovered on same system where eswitch resides:
> +This is the case where PCI PF/VF of a controller and devlink eswitch
> +instance both are located on a single system.
How is eswitch located on a system? Eswitch is in the NIC
I think you should say refer to eswitch being controlled by a system.
> +(2) controller located on external host system.
> +This is the case where a controller is in one system and its devlink
> +eswitch ports are in a different system. Such controller is called
> +external controller.
> +An example view of two controller systems::
> +
> +In this example, external controller (identified by controller number = 1)
> +doesn't have eswitch. Local controller (identified by controller number = 0)
> +has the eswitch. Devlink instance on local Controller has eswitch devlink
> +ports representing networking ports for both the controllers.
> +
> + ---------------------------------------------------------
> + | |
> + | --------- --------- ------- ------- |
> + ----------- | | vf(s) | | sf(s) | |vf(s)| |sf(s)| |
> + | server | | ------- ----/---- ---/----- ------- ---/--- ---/--- |
> + | pci rc |=== | pf0 |______/________/ | pf1 |___/_______/ |
> + | connect | | ------- ------- |
> + ----------- | | controller_num=1 (no eswitch) |
> + ------|--------------------------------------------------
> + (internal wire)
> + |
> + ---------------------------------------------------------
> + | devlink eswitch ports and reps |
> + | ----------------------------------------------------- |
> + | |ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 |ctrl-0 | |
> + | |pf0 | pf0vfN | pf0sfN | pf1 | pf1vfN |pf1sfN | |
> + | ----------------------------------------------------- |
> + | |ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 |ctrl-1 | |
> + | |pf0 | pf0vfN | pf0sfN | pf1 | pf1vfN |pf1sfN | |
> + | ----------------------------------------------------- |
> + | |
> + | |
> + | --------- --------- ------- ------- |
> + | | vf(s) | | sf(s) | |vf(s)| |sf(s)| |
> + | ------- ----/---- ---/----- ------- ---/--- ---/--- |
> + | | pf0 |______/________/ | pf1 |___/_______/ |
> + | ------- ------- |
> + | |
> + | local controller_num=0 (eswitch) |
> + ---------------------------------------------------------
> +
> +Port function configuration
> +===========================
> +
> +When a port flavor is ``DEVLINK_PORT_FLAVOUR_PCI_PF`` or
> +``DEVLINK_PORT_FLAVOUR_PCI_VF``, it represents the networking port of a
> +PCI function.
Networking port of a PCI function?
> A user can configure the port function attributes
port function attributes?
> before
> +enumerating the function.
What does this mean? What does enumerate mean in this context?
> For example user may set the hardware address of
> +the function represented by the devlink port function.
What's a hardware address? You mean MAC address?
Powered by blists - more mailing lists