Date:   Wed, 11 May 2022 21:42:45 +0530
From:   Sumit Gupta <sumitg@...dia.com>
To:     Rob Herring <robh@...nel.org>
CC:     <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <thierry.reding@...il.com>,
        <jonathanh@...dia.com>, <kbuild-all@...ts.01.org>,
        <bbasu@...dia.com>, <vsethi@...dia.com>, <jsequeira@...dia.com>,
        Sumit Gupta <sumitg@...dia.com>
Subject: Re: [Patch v5 2/9] dt-bindings: arm: tegra: Add NVIDIA Tegra194
 CBB1.0 binding



On 11/05/22 20:16, Rob Herring wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Fri, May 06, 2022 at 04:42:10PM +0530, Sumit Gupta wrote:
>> Add device-tree binding documentation to represent the error handling
>> driver for Control Backbone (CBB) version 1.0 used in Tegra194 SOC.
> 
> Bindings are for h/w not drivers.
OK, will change to below ? and send v6.
"Add device-tree binding documentation to represent the Control Backbone 
(CBB) version 1.0 used in Tegra194 SOC."

> 
>> The driver prints debug information about failed transactions due to
>> illegal register accesses on receiving interrupt from CBB.
>>
>> Signed-off-by: Sumit Gupta <sumitg@...dia.com>
>> ---
>>   .../arm/tegra/nvidia,tegra194-cbb.yaml        | 93 +++++++++++++++++++
>>   1 file changed, 93 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..3167f0450298
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra194-cbb.yaml
>> @@ -0,0 +1,93 @@
>> +# 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 device tree bindings
> 
> 'device tree bindings' is redundantOK, will change to below ? and send v6.
"title: NVIDIA Tegra194 CBB 1.0 bindings"

> 
>> +
>> +maintainers:
>> +  - Sumit Gupta <sumitg@...dia.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.
> 
> Please wrap at 80. Longer is allowed, but should still be the exception.
Will do in v6.

> 
>> +
>> +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 ERD register.
>> +
>> +additionalProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - interrupts
>> +  - nvidia,axi2apb
>> +  - nvidia,apbmisc
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> +    cbb-noc@...0000 {
>> +        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>;
>> +        status = "okay";
> 
> Don't need status in examples.
Ok, will remove in v6.

> 
> 
>> +    };
>> --
>> 2.17.1
>>
>>

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