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From:   Lorenzo Pieralisi <lpieralisi@kernel.org>
To:     linux-kernel@vger.kernel.org
Cc:     Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Rob Herring <robh@kernel.org>,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-acpi@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Fang Xiang <fangxiang3@xiaomi.com>,
        Marc Zyngier <maz@kernel.org>
Subject: [PATCH v3 1/5] dt-bindings: interrupt-controller: arm,gic-v3: Add dma-noncoherent property
Date:   Fri,  6 Oct 2023 14:59:25 +0200
Message-Id: <20231006125929.48591-2-lpieralisi@kernel.org>
In-Reply-To: <20231006125929.48591-1-lpieralisi@kernel.org>
References: <20230905104721.52199-1-lpieralisi@kernel.org>
 <20231006125929.48591-1-lpieralisi@kernel.org>
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The GIC v3 specifications allow redistributors and ITSes interconnect
ports used to access memory to be wired up in a way that makes the
respective initiators/memory observers non-coherent.

Add the standard dma-noncoherent property to the GICv3 bindings to
allow firmware to describe the redistributors/ITSes components and
interconnect ports behaviour in system designs where the redistributors
and ITSes are not coherent with the CPU.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Rob Herring <robh@kernel.org>
---
 .../bindings/interrupt-controller/arm,gic-v3.yaml    | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml
index 2bc38479a41e..0f4a062c9d6f 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml
+++ b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml
@@ -106,6 +106,12 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
     maximum: 4096
 
+  dma-noncoherent:
+    description:
+      Present if the GIC redistributors permit programming shareability
+      and cacheability attributes but are connected to a non-coherent
+      downstream interconnect.
+
   msi-controller:
     description:
       Only present if the Message Based Interrupt functionality is
@@ -193,6 +199,12 @@ patternProperties:
       compatible:
         const: arm,gic-v3-its
 
+      dma-noncoherent:
+        description:
+          Present if the GIC ITS permits programming shareability and
+          cacheability attributes but is connected to a non-coherent
+          downstream interconnect.
+
       msi-controller: true
 
       "#msi-cells":
-- 
2.34.1