Documentation/devicetree/bindings/mailbox/ti,omap-mailbox.yaml

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/mailbox/ti,omap-mailbox.yaml

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Documentation/devicetree/bindings/mailbox/ti,omap-mailbox.yaml
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.yaml
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Support Tooling And Documentation
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Documentation
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Support Tooling And Documentation: configuration, schema, or hardware description
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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/mailbox/ti,omap-mailbox.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: TI OMAP2+ and K3 Mailbox devices

maintainers:
  - Suman Anna <s-anna@ti.com>

description: |
  The OMAP Mailbox hardware facilitates communication between different
  processors using a queued mailbox interrupt mechanism. The IP block is
  external to the various processor subsystems and is connected on an
  interconnect bus. The communication is achieved through a set of registers
  for message storage and interrupt configuration registers.

  Each mailbox IP block/cluster has a certain number of h/w fifo queues and
  output interrupt lines. An output interrupt line is routed to an interrupt
  controller within a processor subsystem, and there can be more than one line
  going to a specific processor's interrupt controller. The interrupt line
  connections are fixed for an instance and are dictated by the IP integration
  into the SoC (excluding the SoCs that have an Interrupt Crossbar or an
  Interrupt Router IP). Each interrupt line is programmable through a set of
  interrupt configuration registers, and have a rx and tx interrupt source per
  h/w fifo. Communication between different processors is achieved through the
  appropriate programming of the rx and tx interrupt sources on the appropriate
  interrupt lines.

  The number of h/w fifo queues and interrupt lines dictate the usable
  registers. All the current OMAP SoCs except for the newest DRA7xx SoC has a
  single IP instance. DRA7xx has multiple instances with different number of
  h/w fifo queues and interrupt lines between different instances. The interrupt
  lines can also be routed to different processor sub-systems on DRA7xx as they
  are routed through the Crossbar, a kind of interrupt router/multiplexer. The
  K3 AM65x, J721E and J7200 SoCs has each of these instances form a cluster and
  combine multiple clusters into a single IP block present within the Main
  NavSS. The interrupt lines from all these clusters are multiplexed and routed
  to different processor subsystems over a limited number of common interrupt
  output lines of an Interrupt Router. The AM64x SoCS also uses a single IP
  block comprising of multiple clusters, but the number of clusters are
  smaller, and the interrupt output lines are connected directly to various
  processors.

  Mailbox Controller Nodes
  =========================
  A Mailbox device node is used to represent a Mailbox IP instance/cluster
  within a SoC. The sub-mailboxes (actual communication channels) are
  represented as child nodes of this parent node.

  Mailbox Users
  ==============
  A device needing to communicate with a target processor device should specify
  them using the common mailbox binding properties, "mboxes" and the optional
  "mbox-names" (please see Documentation/devicetree/bindings/mailbox/mailbox.txt
  for details). Each value of the mboxes property should contain a phandle to
  the mailbox controller device node and an args specifier that will be the
  phandle to the intended sub-mailbox child node to be used for communication.
  The equivalent "mbox-names" property value can be used to give a name to the
  communication channel to be used by the client user.

$defs:
  omap-mbox-descriptor:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    description:
      The omap-mbox-descriptor is made of up of 3 cells and represents a single
      uni-directional communication channel. A typical sub-mailbox device uses
      two such channels - one for transmitting (Tx) and one for receiving (Rx).
    items:

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