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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 2/9] dt-bindings: arm: tegra: Add NVIDIA Tegra194 CBB1.0 binding
Date:   Thu, 12 May 2022 01:46:44 +0530
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Add device-tree binding documentation to represent the
Control Backbone (CBB) version 1.0 used in Tegra194 SOC.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
 .../arm/tegra/nvidia,tegra194-cbb.yaml        | 98 +++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/tegra/nvidia,tegra194-cbb.yaml

diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra194-cbb.yaml b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra194-cbb.yaml
new file mode 100644
index 000000000000..f967b45e83d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra194-cbb.yaml
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/arm/tegra/nvidia,tegra194-cbb.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: NVIDIA Tegra194 CBB 1.0 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 1.0 has
+  multiple hierarchical sub-NOCs (Network-on-Chip) and connects various
+  initiators and targets using different bridges like AXIP2P, AXI2APB.
+
+  This driver handles errors due to illegal register accesses reported
+  by the NOCs inside the CBB. NOCs reporting errors are cluster NOCs
+  "AON-NOC, SCE-NOC, RCE-NOC, BPMP-NOC, CV-NOC" and "CBB Central NOC"
+  which is the main NOC.
+
+  By default, the access issuing initiator is informed about the error
+  using SError or Data Abort exception unless the ERD (Error Response
+  Disable) is enabled/set for that initiator. If the ERD is enabled, then
+  SError or Data Abort is masked and the error is reported with interrupt.
+
+  - For CCPLEX (CPU Complex) initiator, the driver sets ERD bit. So, the
+    errors due to illegal accesses from CCPLEX are reported by interrupts.
+    If ERD is not set, then error is reported by SError.
+  - For other initiators, the ERD is disabled. So, the access issuing
+    initiator is informed about the illegal access by Data Abort exception.
+    In addition, an interrupt is also generated to CCPLEX. These initiators
+    include all engines using Cortex-R5 (which is ARMv7 CPU cluster) and
+    engines like TSEC (Security co-processor), NVDEC (NVIDIA Video Decoder
+    engine) etc which can initiate transactions.
+
+  The driver prints relevant debug information like Error Code, Error
+  Description, Master, Address, AXI ID, Cache, Protection, Security Group
+  etc on receiving error notification.
+
+properties:
+  $nodename:
+    pattern: "^[a-z]+-noc@[0-9a-f]+$"
+
+  compatible:
+    enum:
+      - nvidia,tegra194-cbb-noc
+      - nvidia,tegra194-aon-noc
+      - nvidia,tegra194-bpmp-noc
+      - nvidia,tegra194-rce-noc
+      - nvidia,tegra194-sce-noc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description:
+      CCPLEX receives secure or nonsecure interrupt depending on error type.
+      A secure interrupt is received for SEC(firewall) & SLV errors and a
+      non-secure interrupt is received for TMO & DEC errors.
+    items:
+      - description: non-secure interrupt
+      - description: secure interrupt
+
+  nvidia,axi2apb:
+    $ref: '/schemas/types.yaml#/definitions/phandle'
+    description:
+      Specifies the node having all axi2apb bridges which need to be checked
+      for any error logged in their status register.
+
+  nvidia,apbmisc:
+    $ref: '/schemas/types.yaml#/definitions/phandle'
+    description:
+      Specifies the apbmisc node which need to be used for reading the ERD
+      register.
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - nvidia,axi2apb
+  - nvidia,apbmisc
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    cbb-noc@2300000 {
+        compatible = "nvidia,tegra194-cbb-noc";
+        reg = <0x02300000 0x1000>;
+        interrupts = <GIC_SPI 230 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 231 IRQ_TYPE_LEVEL_HIGH>;
+        nvidia,axi2apb = <&axi2apb>;
+        nvidia,apbmisc = <&apbmisc>;
+    };
-- 
2.17.1