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From:   Sumit Gupta <sumitg@nvidia.com>
To:     <linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <thierry.reding@gmail.com>,
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CC:     <sumitg@nvidia.com>, <bbasu@nvidia.com>, <vsethi@nvidia.com>,
        <jsequeira@nvidia.com>
Subject: [Patch v6 6/9] dt-bindings: arm: tegra: Add NVIDIA Tegra234 CBB2.0 binding
Date:   Thu, 12 May 2022 01:46:48 +0530
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Add device-tree binding documentation to represent
the Control Backbone (CBB) version 2.0 used in T234 SoC.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
 .../arm/tegra/nvidia,tegra234-cbb.yaml        | 74 +++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/tegra/nvidia,tegra234-cbb.yaml

diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra234-cbb.yaml b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra234-cbb.yaml
new file mode 100644
index 000000000000..7b1fe50ffbe0
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra234-cbb.yaml
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/arm/tegra/nvidia,tegra234-cbb.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: NVIDIA Tegra CBB 2.0 bindings
+
+maintainers:
+  - Sumit Gupta <sumitg@nvidia.com>
+
+description: |+
+  The Control Backbone (CBB) is comprised of the physical path from an
+  initiator to a target's register configuration space. CBB 2.0 consists
+  of multiple sub-blocks connected to each other to create a topology.
+  The Tegra234 SoC has different fabrics based on CBB 2.0 architecture
+  which include cluster fabrics BPMP, AON, PSC, SCE, RCE, DCE, FSI and
+  "CBB central fabric".
+
+  In CBB 2.0, each initiator which can issue transactions connects to a
+  Root Master Node (MN) before it connects to any other element of the
+  fabric. Each Root MN contains a Error Monitor (EM) which detects and
+  logs error. Interrupts from various EM blocks are collated by Error
+  Notifier (EN) which is per fabric and presents a single interrupt from
+  fabric to the SoC interrupt controller.
+
+  The driver handles errors from CBB due to illegal register accesses
+  and prints debug information about failed transaction on receiving
+  the interrupt from EN. Debug information includes Error Code, Error
+  Description, MasterID, Fabric, SlaveID, Address, Cache, Protection,
+  Security Group etc on receiving error notification.
+
+  If the Error Response Disable (ERD) is set/enabled for an initiator,
+  then SError or Data abort exception error response is masked and an
+  interrupt is used for reporting errors due to illegal accesses from
+  that initiator. The value returned on read failures is '0xFFFFFFFF'
+  for compatibility with PCIE.
+
+properties:
+  $nodename:
+    pattern: "^[a-z]+-fabric@[0-9a-f]+$"
+
+  compatible:
+    enum:
+      - nvidia,tegra234-aon-fabric
+      - nvidia,tegra234-bpmp-fabric
+      - nvidia,tegra234-cbb-fabric
+      - nvidia,tegra234-dce-fabric
+      - nvidia,tegra234-rce-fabric
+      - nvidia,tegra234-sce-fabric
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: secure interrupt from error notifier
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    cbb-fabric@1300000 {
+      compatible = "nvidia,tegra234-cbb-fabric";
+      reg = <0x13a00000 0x400000>;
+      interrupts = <GIC_SPI 231 IRQ_TYPE_LEVEL_HIGH>;
+    };
-- 
2.17.1