1# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/mailbox/apple,mailbox.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Apple Mailbox Controller
8
9maintainers:
10  - Hector Martin <marcan@marcan.st>
11  - Sven Peter <sven@svenpeter.dev>
12
13description:
14  The Apple mailbox consists of two FIFOs used to exchange 64+32 bit
15  messages between the main CPU and a co-processor. Multiple instances
16  of this mailbox can be found on Apple SoCs.
17  One of the two FIFOs is used to send data to a co-processor while the other
18  FIFO is used for the other direction.
19  Various clients implement different IPC protocols based on these simple
20  messages and shared memory buffers.
21
22properties:
23  compatible:
24    oneOf:
25      - description:
26          ASC mailboxes are the most common variant found on the M1 used
27          for example for the display controller, the system management
28          controller and the NVMe coprocessor.
29        items:
30          - const: apple,t8103-asc-mailbox
31
32      - description:
33          M3 mailboxes are an older variant with a slightly different MMIO
34          interface still found on the M1. It is used for the Thunderbolt
35          co-processors.
36        items:
37          - const: apple,t8103-m3-mailbox
38
39  reg:
40    maxItems: 1
41
42  interrupts:
43    items:
44      - description: send fifo is empty interrupt
45      - description: send fifo is not empty interrupt
46      - description: receive fifo is empty interrupt
47      - description: receive fifo is not empty interrupt
48
49  interrupt-names:
50    items:
51      - const: send-empty
52      - const: send-not-empty
53      - const: recv-empty
54      - const: recv-not-empty
55
56  "#mbox-cells":
57    const: 0
58
59required:
60  - compatible
61  - reg
62  - interrupts
63  - interrupt-names
64  - "#mbox-cells"
65
66additionalProperties: false
67
68examples:
69  - |
70        mailbox@77408000 {
71                compatible = "apple,t8103-asc-mailbox";
72                reg = <0x77408000 0x4000>;
73                interrupts = <1 583 4>, <1 584 4>, <1 585 4>, <1 586 4>;
74                interrupt-names = "send-empty", "send-not-empty",
75                 "recv-empty", "recv-not-empty";
76                #mbox-cells = <0>;
77        };
78