Date:   Wed, 8 Jan 2020 11:05:01 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Rob Herring <robh@...nel.org>
CC:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Andrew Murray <andrew.murray@....com>,
        <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 01/14] dt-bindings: PCI: cadence: Add PCIe RC/EP DT
 schema for Cadence PCIe

Hi Rob,

On 08/01/20 9:13 AM, Rob Herring wrote:
> On Mon, Jan 06, 2020 at 03:50:45PM +0530, Kishon Vijay Abraham I wrote:
>> Add PCIe Host (RC) and Endpoint (EP) device tree schema for Cadence
>> PCIe core library. Platforms using Cadence PCIe core can include the
>> schemas added here in the platform specific schemas.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
>> ---
>>  .../devicetree/bindings/pci/cdns-pcie-ep.yaml | 20 ++++++++++++
>>  .../bindings/pci/cdns-pcie-host.yaml          | 30 +++++++++++++++++
>>  .../devicetree/bindings/pci/cdns-pcie.yaml    | 32 +++++++++++++++++++
>>  3 files changed, 82 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml
>>  create mode 100644 Documentation/devicetree/bindings/pci/cdns-pcie-host.yaml
>>  create mode 100644 Documentation/devicetree/bindings/pci/cdns-pcie.yaml
> 
> Need to remove the old files.
> 
> Note that I posted a conversion of Cadence host[1]. Yours goes further, 
> but please compare and add anything mine has that yours doesn't.
> 
> [1] https://lore.kernel.org/linux-pci/20191231193903.15929-2-robh@kernel.org/

Sure, I'll look at this.

Recently we converted Cadence driver to a library since the same Cadence
core can be used by multiple vendors. Here I'm trying to add the
bindings for Cadence core which can be included in the platform specific
schema.

So the existing cdns,cdns-pcie-host.yaml which is a Cadence platform
using Cadence core should include cdns-pcie-host.yaml.

"[PATCH v2 10/14] dt-bindings: PCI: Add host mode dt-bindings for TI's
J721E SoC" in this series includes "cdns-pcie-host.yaml" for TI platform
using Cadence core.

That's why in the schema added here you don't see the compatible since
that will be added in platform specific schema.
> 
>>
>> diff --git a/Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml
>> new file mode 100644
>> index 000000000000..36aaae5931c3
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml
>> @@ -0,0 +1,20 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +# Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
>> +%YAML 1.2
>> +--
>> +$id: "http://devicetree.org/schemas/pci/cdns-pcie-ep.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Cadence PCIe Endpoint
>> +
>> +maintainers:
>> +  - Tom Joseph <tjoseph@...ence.com>
>> +
>> +allOf:
>> +  - $ref: "cdns-pcie.yaml#"
>> +
>> +properties:
>> +  max-functions:
>> +    description: Maximum number of functions that can be configured (default 1)
>> +    allOf:
>> +      - $ref: /schemas/types.yaml#/definitions/uint8
>> diff --git a/Documentation/devicetree/bindings/pci/cdns-pcie-host.yaml b/Documentation/devicetree/bindings/pci/cdns-pcie-host.yaml
>> new file mode 100644
>> index 000000000000..78261bc4f0c5
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pci/cdns-pcie-host.yaml
>> @@ -0,0 +1,30 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +# Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
>> +%YAML 1.2
>> +---
>> +$id: "http://devicetree.org/schemas/pci/cdns-pcie-host.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Cadence PCIe Host
>> +
>> +maintainers:
>> +  - Tom Joseph <tjoseph@...ence.com>
>> +
>> +allOf:
>> +  - $ref: "/schemas/pci/pci-bus.yaml#"
>> +  - $ref: "cdns-pcie.yaml#"
>> +
>> +properties:
>> +  vendor-id:
>> +    description: The PCI vendor ID (16 bits, default is design dependent)
>> +
>> +  device-id:
>> +    description: The PCI device ID (16 bits, default is design dependent)
> 
> While these got defined here as 16-bits, these should be fixed to 32-bit 
> because they are established properties for a long time.
> 
>> +
>> +  cdns,no-bar-match-nbits:
>> +    description: Set into the no BAR match register to configure the number
>> +      of least significant bits kept during inbound (PCIe -> AXI) address
>> +      translations (default 32)
>> +    allOf:
>> +      - $ref: /schemas/types.yaml#/definitions/uint32
> 
> What about compatible?
> 
>> +
>> diff --git a/Documentation/devicetree/bindings/pci/cdns-pcie.yaml b/Documentation/devicetree/bindings/pci/cdns-pcie.yaml
>> new file mode 100644
>> index 000000000000..497d3dc2e6f2
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pci/cdns-pcie.yaml
>> @@ -0,0 +1,32 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +# Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
>> +%YAML 1.2
>> +---
>> +$id: "http://devicetree.org/schemas/pci/cdns-pcie.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Cadence PCIe Core
>> +
>> +maintainers:
>> +  - Tom Joseph <tjoseph@...ence.com>
>> +
>> +properties:
>> +  max-link-speed:
>> +    minimum: 1
>> +    maximum: 3
>> +
>> +  num-lanes:
>> +    minimum: 1
>> +    maximum: 2
> 
> Needs a type.
> 
> The Cadence IP can't support x4, x8, or x16?

I'll fix this. I assume these can be overwritten in platform specific
schema files?

Thanks
Kishon

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