[v2,2/3] dt-bindings: iommu: add DART iommu bindings

Commit Message

Sven Peter March 28, 2021, 7:40 a.m. UTC

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

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

Comments

Arnd Bergmann March 28, 2021, 8:16 a.m. UTC | #1

On Sun, Mar 28, 2021 at 9:40 AM Sven Peter <[e-mail]> wrote:

I noticed only one detail here:

> +  - |+
> +    dart2a: dart2a@82f00000 {
> +      compatible = "apple,t8103-dart";
> +      reg = <0x82f00000 0x4000>;
> +      interrupts = <1 781 4>;
> +      #iommu-cells = <1>;
> +    };

The name of the iommu should be iommu@82f00000, not dart2a@82f00000.

       Arnd

Sven Peter March 28, 2021, 9:22 a.m. UTC | #2

On Sun, Mar 28, 2021, at 10:16, Arnd Bergmann wrote:
> On Sun, Mar 28, 2021 at 9:40 AM Sven Peter <[e-mail]> wrote:
> 
> I noticed only one detail here:
> 
> > +  - |+
> > +    dart2a: dart2a@82f00000 {
> > +      compatible = "apple,t8103-dart";
> > +      reg = <0x82f00000 0x4000>;
> > +      interrupts = <1 781 4>;
> > +      #iommu-cells = <1>;
> > +    };
> 
> The name of the iommu should be iommu@82f00000, not dart2a@82f00000.
> 
>        Arnd
>

Thanks, fixed for v3. I've also just noticed that I forgot to update
the filename in MAINTAINERS after I renamed it from apple,t8103-dart.yaml
which I've fixed as well.


Sven

Patch

diff --git a/Documentation/devicetree/bindings/iommu/apple,dart.yaml b/Documentation/devicetree/bindings/iommu/apple,dart.yaml
new file mode 100644
index 000000000000..c0b43d90c157
--- /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 <[e-mail]>
+
+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: dart1@82f80000 {
+      compatible = "apple,t8103-dart";
+      reg = <0x82f80000 0x4000>;
+      interrupts = <1 781 4>;
+      #iommu-cells = <1>;
+    };
+
+    master1 {
+      iommus = <&{/dart1} 0>;
+    };
+
+  - |+
+    dart2a: dart2a@82f00000 {
+      compatible = "apple,t8103-dart";
+      reg = <0x82f00000 0x4000>;
+      interrupts = <1 781 4>;
+      #iommu-cells = <1>;
+    };
+    dart2b: dart2@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 9ac46317840b..f5397328fa1f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1236,6 +1236,12 @@  L:	[e-mail]
 S:	Odd fixes
 F:	drivers/input/mouse/bcm5974.c
 
+APPLE DART IOMMU DRIVER
+M:	Sven Peter <[e-mail]>
+L:	[e-mail]
+S:	Maintained
+F:	Documentation/devicetree/bindings/iommu/apple,t8103-dart.yaml
+
 APPLE SMC DRIVER
 M:	Henrik Rydberg <[e-mail]>
 L:	[e-mail]