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From:   Sumit Gupta <sumitg@nvidia.com>
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Subject: [Patch v3 6/9] dt-bindings: arm: tegra: Add NVIDIA Tegra234 CBB2.0 binding
Date:   Tue, 21 Dec 2021 18:21:14 +0530
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Add device-tree binding documentation to represent CBB2.0 (Control
Backbone) error handling driver. The driver prints debug information
about failed transaction on receiving interrupt from CBB2.0.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
 .../arm/tegra/nvidia,tegra234-cbb.yaml        | 70 +++++++++++++++++++
 1 file changed, 70 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..fa4383be19d8
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra234-cbb.yaml
@@ -0,0 +1,70 @@
+# 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 Error handling driver device tree 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 CBB2.0 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: true
+
+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>;
+      status = "okay";
+    };
-- 
2.17.1