[PATCH v2 1/2] dt-bindings: mailbox: Add Apple mailbox bindings

From: Sven Peter
Date: Thu Sep 16 2021 - 11:49:55 EST


Apple mailbox controller are found on the M1 and are used for
communication with various co-processors.

Reviewed-by: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
Reviewed-by: Mark Kettenis <kettenis@xxxxxxxxxxx>
Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx>
---
.../bindings/mailbox/apple,mailbox.yaml | 84 +++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 85 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml b/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
new file mode 100644
index 000000000000..79b0cef08232
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
@@ -0,0 +1,84 @@
+# 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@xxxxxxxxx>
+ - Sven Peter <sven@xxxxxxxxxxxxx>
+
+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:
+ - const: apple,t8103-asc-mailbox
+
+ - 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:
+ - const: apple,t8103-m3-mailbox
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ minItems: 4
+ 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:
+ minItems: 4
+ items:
+ - const: send-empty
+ - const: send-not-empty
+ - const: recv-empty
+ - const: recv-not-empty
+
+ clocks:
+ description:
+ Reference to the clock gate phandle(s) if required for this mailbox.
+ Optional since not all mailboxes are attached to a clock gate.
+
+ "#mbox-cells":
+ const: 0
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - interrupt-names
+ - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ mailbox@77408000 {
+ compatible = "apple,t8103-asc-mailbox";
+ 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>;
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index cad1289793db..47de27282c98 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1720,6 +1720,7 @@ C: irc://irc.oftc.net/asahi-dev
T: git https://github.com/AsahiLinux/linux.git
F: Documentation/devicetree/bindings/arm/apple.yaml
F: Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
+F: Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
F: Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml
F: arch/arm64/boot/dts/apple/
F: drivers/irqchip/irq-apple-aic.c
--
2.25.1