Subject: [PATCH v3 2/3] dt-bindings: iommu: add DART iommu bindings

From: Sven Peter <[email-masked]>
Date: Thu, 3 Jun 2021 10:50:02 +0200

DART (Device Address Resolution Table) is the iommu found on Apple
ARM SoCs such as the M1.

Signed-off-by: Sven Peter <[email-masked]>
---
 .../devicetree/bindings/iommu/apple,dart.yaml | 81 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 87 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iommu/apple,dart.yaml

diff --git a/Documentation/devicetree/bindings/iommu/apple,dart.yaml b/Documentation/devicetree/bindings/iommu/apple,dart.yaml
new file mode 100644
index 000000000000..db21ca07d121
--- /dev/null
+++ b/Documentation/devicetree/bindings/iommu/apple,dart.yaml
@@ -0,0 +1,81 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iommu/apple,dart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple DART IOMMU
+
+maintainers:
+  - Sven Peter <[email-masked]>
+
+description: |+
+  Apple SoCs may contain an implementation of their Device Address
+  Resolution Table which provides a mandatory layer of address
+  translations for various masters.
+
+  Each DART instance is capable of handling up to 16 different streams
+  with individual pagetables and page-level read/write protection flags.
+
+  This DART IOMMU also raises interrupts in response to various
+  fault conditions.
+
+properties:
+  compatible:
+    const: apple,t8103-dart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description:
+      Reference to the gate clock phandle if required for this IOMMU.
+      Optional since not all IOMMUs are attached to a clock gate.
+
+  '#iommu-cells':
+    const: 1
+    description:
+      Has to be one. The single cell describes the stream id emitted by
+      a master to the IOMMU.
+
+required:
+  - compatible
+  - reg
+  - '#iommu-cells'
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |+
+    dart1: iommu@82f80000 {
+      compatible = "apple,t8103-dart";
+      reg = <0x82f80000 0x4000>;
+      interrupts = <1 781 4>;
+      #iommu-cells = <1>;
+    };
+
+    master1 {
+      iommus = <&{/dart1} 0>;
+    };
+
+  - |+
+    dart2a: iommu@82f00000 {
+      compatible = "apple,t8103-dart";
+      reg = <0x82f00000 0x4000>;
+      interrupts = <1 781 4>;
+      #iommu-cells = <1>;
+    };
+    dart2b: iommu@82f80000 {
+      compatible = "apple,t8103-dart";
+      reg = <0x82f80000 0x4000>;
+      interrupts = <1 781 4>;
+      #iommu-cells = <1>;
+    };
+
+    master2 {
+      iommus = <&{/dart2a} 0>, <&{/dart2b} 1>;
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 673cadd5107a..4373d63f9ccf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1240,6 +1240,12 @@ L:	[email-masked]
 S:	Odd fixes
 F:	drivers/input/mouse/bcm5974.c
 
+APPLE DART IOMMU DRIVER
+M:	Sven Peter <[email-masked]>
+L:	[email-masked]
+S:	Maintained
+F:	Documentation/devicetree/bindings/iommu/apple,dart.yaml
+
 APPLE SMC DRIVER
 M:	Henrik Rydberg <[email-masked]>
 L:	[email-masked]
-- 
2.25.1

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