321f7ab0d4
The switch ASIC has a limited capacity of physical ('flavour physical'
in devlink terminology) ports that it can support. While each system is
brought up with a different number of ports, this number can be
increased via splitting up to the ASIC's limit.
Expose physical ports as a devlink resource so that user space will have
visibility to the maximum number of ports that can be supported and the
current occupancy.
In addition, add a "Generic Resources" section in devlink-resource
documentation so the different drivers will be aligned by the same resource
name when exposing to user space.
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.. SPDX-License-Identifier: GPL-2.0
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================
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Devlink Resource
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================
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``devlink`` provides the ability for drivers to register resources, which
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can allow administrators to see the device restrictions for a given
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resource, as well as how much of the given resource is currently
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in use. Additionally, these resources can optionally have configurable size.
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This could enable the administrator to limit the number of resources that
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are used.
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For example, the ``netdevsim`` driver enables ``/IPv4/fib`` and
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``/IPv4/fib-rules`` as resources to limit the number of IPv4 FIB entries and
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rules for a given device.
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Resource Ids
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============
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Each resource is represented by an id, and contains information about its
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current size and related sub resources. To access a sub resource, you
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specify the path of the resource. For example ``/IPv4/fib`` is the id for
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the ``fib`` sub-resource under the ``IPv4`` resource.
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Generic Resources
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=================
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Generic resources are used to describe resources that can be shared by multiple
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device drivers and their description must be added to the following table:
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.. list-table:: List of Generic Resources
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:widths: 10 90
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* - Name
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- Description
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* - ``physical_ports``
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- A limited capacity of physical ports that the switch ASIC can support
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example usage
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-------------
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The resources exposed by the driver can be observed, for example:
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.. code:: shell
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$devlink resource show pci/0000:03:00.0
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pci/0000:03:00.0:
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name kvd size 245760 unit entry
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resources:
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name linear size 98304 occ 0 unit entry size_min 0 size_max 147456 size_gran 128
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name hash_double size 60416 unit entry size_min 32768 size_max 180224 size_gran 128
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name hash_single size 87040 unit entry size_min 65536 size_max 212992 size_gran 128
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Some resource's size can be changed. Examples:
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.. code:: shell
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$devlink resource set pci/0000:03:00.0 path /kvd/hash_single size 73088
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$devlink resource set pci/0000:03:00.0 path /kvd/hash_double size 74368
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The changes do not apply immediately, this can be validated by the 'size_new'
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attribute, which represents the pending change in size. For example:
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.. code:: shell
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$devlink resource show pci/0000:03:00.0
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pci/0000:03:00.0:
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name kvd size 245760 unit entry size_valid false
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resources:
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name linear size 98304 size_new 147456 occ 0 unit entry size_min 0 size_max 147456 size_gran 128
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name hash_double size 60416 unit entry size_min 32768 size_max 180224 size_gran 128
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name hash_single size 87040 unit entry size_min 65536 size_max 212992 size_gran 128
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Note that changes in resource size may require a device reload to properly
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take effect.
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