[PATCH net-next 1/2] dt-bindings: net: Add Axiado AX3005 IRoT MCTP transport

[Akhila Kavi]

The Axiado AX3005 SoC has an integrated root-of-trust (IRoT)
co-processor next to the application processor. The two exchange MCTP
packets through a no-map carve-out in DRAM, and use one channel in each
direction of the AX3005 mailbox controller as doorbells.

Add a binding for this link. The node has no registers of its own. It
describes the fixed pairing of a TX and an RX mailbox channel with the
reserved-memory carve-out that the IRoT places its packet windows in.
The IRoT firmware chooses the window addresses inside the carve-out and
reports them at runtime, so they are not described in the devicetree.

Also add a MAINTAINERS entry covering the binding.

Signed-off-by: Akhila Kavi <akavi at axiado.com>
---
 .../bindings/net/axiado,ax3005-mctp-irot.yaml      | 60 ++++++++++++++++++++++
 MAINTAINERS                                        |  8 +++
 2 files changed, 68 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/axiado,ax3005-mctp-irot.yaml b/Documentation/devicetree/bindings/net/axiado,ax3005-mctp-irot.yaml
new file mode 100644
index 000000000000..795949a4444f
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/axiado,ax3005-mctp-irot.yaml
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/axiado,ax3005-mctp-irot.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Axiado AX3005 IRoT MCTP Transport
+
+maintainers:
+  - Akhila Kavi <akavi at axiado.com>
+  - Sammai Chakravarthy <schakravarthy at axiado.com>
+  - Prasad Bolisetty <pbolisetty at axiado.com>
+
+description: |
+  MCTP transport between the AX3005 application processor and its
+  root-of-trust (IRoT) co-processor. MCTP packets are carried in two
+  shared-memory windows, one per direction, and a pair of mailbox channels
+  act as doorbells: "tx" (processor to co-processor) and "rx" (co-processor
+  to processor).
+
+  The co-processor allocates both windows from the carve-out referenced by
+  memory-region and reports their addresses at runtime.
+
+properties:
+  compatible:
+    const: axiado,ax3005-mctp-irot
+
+  mboxes:
+    items:
+      - description: TX doorbell channel (Processor to Co-Processor)
+      - description: RX doorbell channel (Co-Processor to Processor)
+
+  mbox-names:
+    items:
+      - const: tx
+      - const: rx
+
+  memory-region:
+    maxItems: 1
+    description:
+      No-map carve-out that the co-processor allocates both MCTP windows
+      from.
+
+required:
+  - compatible
+  - mboxes
+  - mbox-names
+  - memory-region
+
+additionalProperties: false
+
+examples:
+  - |
+    mctp {
+        compatible = "axiado,ax3005-mctp-irot";
+        /* AX3005 mailbox channels 0-7 are TX, 8-15 are RX */
+        mboxes = <&mailbox0 0>, <&mailbox0 8>;
+        mbox-names = "tx", "rx";
+        memory-region = <&irot_mctp_mem>;
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 360977678f70..b16248974044 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4477,6 +4477,14 @@ S:	Supported
 F:	Documentation/devicetree/bindings/mailbox/axiado,ax3005-mailbox.yaml
 F:	drivers/mailbox/axiado-mailbox.c
 
+AXIADO MCTP IROT DRIVER
+M:	Akhila Kavi <akavi at axiado.com>
+M:	Sammai Chakravarthy <schakravarthy at axiado.com>
+M:	Prasad Bolisetty <pbolisetty at axiado.com>
+L:	netdev at vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/net/axiado,ax3005-mctp-irot.yaml
+
 AXI SPI ENGINE
 M:	Michael Hennerich <michael.hennerich at analog.com>
 M:	Nuno Sá <nuno.sa at analog.com>

-- 
2.34.1