# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause %YAML 1.2 --- $id: http://devicetree.org/schemas/mailbox/apple,mailbox.yaml# $schema: http://devicetree.org/meta-schemas/core.yaml# title: Apple Mailbox Controller maintainers: - Hector Martin <marcan@marcan.st> - Sven Peter <sven@svenpeter.dev> description: The Apple mailbox consists of two FIFOs used to exchange 64+32 bit messages between the main CPU and a co-processor. Multiple instances of this mailbox can be found on Apple SoCs. One of the two FIFOs is used to send data to a co-processor while the other FIFO is used for the other direction. Various clients implement different IPC protocols based on these simple messages and shared memory buffers. properties: compatible: oneOf: - description: ASC mailboxes are the most common variant found on the M1 used for example for the display controller, the system management controller and the NVMe coprocessor. items: - enum: - apple,t8103-asc-mailbox - apple,t6000-asc-mailbox - const: apple,asc-mailbox-v4 - description: M3 mailboxes are an older variant with a slightly different MMIO interface still found on the M1. It is used for the Thunderbolt co-processors. items: - enum: - apple,t8103-m3-mailbox - apple,t6000-m3-mailbox - const: apple,m3-mailbox-v2 reg: maxItems: 1 interrupts: items: - description: send fifo is empty interrupt - description: send fifo is not empty interrupt - description: receive fifo is empty interrupt - description: receive fifo is not empty interrupt interrupt-names: items: - const: send-empty - const: send-not-empty - const: recv-empty - const: recv-not-empty "#mbox-cells": const: 0 power-domains: maxItems: 1 required: - compatible - reg - interrupts - interrupt-names - "#mbox-cells" additionalProperties: false examples: - | mailbox@77408000 { compatible = "apple,t8103-asc-mailbox", "apple,asc-mailbox-v4"; reg = <0x77408000 0x4000>; interrupts = <1 583 4>, <1 584 4>, <1 585 4>, <1 586 4>; interrupt-names = "send-empty", "send-not-empty", "recv-empty", "recv-not-empty"; #mbox-cells = <0>; };