Commit d7218d3c authored by Oleksii Moisieiev's avatar Oleksii Moisieiev Committed by Alexandre Torgue
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dt-bindings: document generic access controllers 

Introducing of the generic access controllers bindings for the
access controller provider and consumer devices. Those bindings are
intended to allow a better handling of accesses to resources in a
hardware architecture supporting several compartments.

This patch is based on [1]. It is integrated in this patchset as it
provides a use-case for it.

Diffs with [1]:
	- Rename feature-domain* properties to access-control* to narrow
	  down the scope of the binding
	- YAML errors and typos corrected.
	- Example updated
	- Some rephrasing in the binding description

[1]: https://lore.kernel.org/lkml/0c0a82bb-18ae-d057-562b



Signed-off-by: default avatarOleksii Moisieiev <Oleksii_Moisieiev@epam.com>
Signed-off-by: default avatarGatien Chevallier <gatien.chevallier@foss.st.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarAlexandre Torgue <alexandre.torgue@foss.st.com>
parent 4cece764

Documentation/devicetree/bindings/access-controllers/access-controllers.yaml

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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/access-controllers/access-controllers.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#



title: Generic Domain Access Controllers



maintainers:

  - Oleksii Moisieiev <oleksii_moisieiev@epam.com>



description: |+

  Common access controllers properties



  Access controllers are in charge of stating which of the hardware blocks under

  their responsibility (their domain) can be accesssed by which compartment. A

  compartment can be a cluster of CPUs (or coprocessors), a range of addresses

  or a group of hardware blocks. An access controller's domain is the set of

  resources covered by the access controller.



  This device tree binding can be used to bind devices to their access

  controller provided by access-controllers property. In this case, the device

  is a consumer and the access controller is the provider.



  An access controller can be represented by any node in the device tree and

  can provide one or more configuration parameters, needed to control parameters

  of the consumer device. A consumer node can refer to the provider by phandle

  and a set of phandle arguments, specified by '#access-controller-cells'

  property in the access controller node.



  Access controllers are typically used to set/read the permissions of a

  hardware block and grant access to it. Any of which depends on the access

  controller. The capabilities of each access controller are defined by the

  binding of the access controller device.



  Each node can be a consumer for the several access controllers.



# always select the core schema

select: true



properties:

  "#access-controller-cells":

    description:

      Number of cells in an access-controllers specifier;

      Can be any value as specified by device tree binding documentation

      of a particular provider. The node is an access controller.



  access-controller-names:

    $ref: /schemas/types.yaml#/definitions/string-array

    description:

      A list of access-controllers names, sorted in the same order as

      access-controllers entries. Consumer drivers will use

      access-controller-names to match with existing access-controllers entries.



  access-controllers:

    $ref: /schemas/types.yaml#/definitions/phandle-array

    description:

      A list of access controller specifiers, as defined by the

      bindings of the access-controllers provider.



additionalProperties: true



examples:

  - |

    clock_controller: access-controllers@50000 {

        reg = <0x50000 0x400>;

        #access-controller-cells = <2>;

    };



    bus_controller: bus@60000 {

        reg = <0x60000 0x10000>;

        #address-cells = <1>;

        #size-cells = <1>;

        ranges;

        #access-controller-cells = <3>;



        uart4: serial@60100 {

            reg = <0x60100 0x400>;

            clocks = <&clk_serial>;

            access-controllers = <&clock_controller 1 2>,

                                 <&bus_controller 1 3 5>;

            access-controller-names = "clock", "bus";

        };

    };