Re: [DT-SCHEMA PATCH V1] schemas: pci: Extend the meaning of 'linux,pci-probe-only'

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Feb 22, 2024 at 06:12:31PM +0530, Vidya Sagar wrote:
> Extend the meaning of 'linux,pci-probe-only' to cover the cases where
> it is applicable only to a specific PCIe host bridge if defined in a
> PCIe node instead of chosen node. Add the documentation for the same
> in schemas/pci/pci-host-bridge.yaml

This isn't specific to PCIe, it's generic to PCI.

> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> ---
>  dtschema/schemas/chosen.yaml              | 2 ++
>  dtschema/schemas/pci/pci-host-bridge.yaml | 8 ++++++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/dtschema/schemas/chosen.yaml b/dtschema/schemas/chosen.yaml
> index 6d5c3f1..9152df3 100644
> --- a/dtschema/schemas/chosen.yaml
> +++ b/dtschema/schemas/chosen.yaml
> @@ -144,6 +144,8 @@ properties:
>        Optional property which takes a single-cell argument. If '0', then Linux
>        will assign devices in its usual manner, otherwise it will not try to
>        assign devices and instead use them as they are configured already.
> +      NOTE:- To restrict the applicability of this property to a specific PCIe
> +             host bridge, please refer to /schemas/pci/pci-host-bridge.yaml
>  
>    stdout-path:
>      $ref: types.yaml#/definitions/string
> diff --git a/dtschema/schemas/pci/pci-host-bridge.yaml b/dtschema/schemas/pci/pci-host-bridge.yaml
> index fbbb829..d6d595d 100644
> --- a/dtschema/schemas/pci/pci-host-bridge.yaml
> +++ b/dtschema/schemas/pci/pci-host-bridge.yaml
> @@ -31,6 +31,14 @@ properties:
>        number for each host bridge in the system must be unique.
>      $ref: /schemas/types.yaml#/definitions/uint32
>  
> +  linux,pci-probe-only:
> +    description: If present, Linux will not try to assign devices and instead
> +      use them as they are configured already by the platform firmware for this
> +      particular host bridge.

I think it would be more precise to say that Linux will not reassign
BARs or bridge windows.  "Assign devices" seems a little bit
ambiguous.

> +      NOTE:- If defined in chosen node, this property has system wide applicability.
> +             Please refer to /schemas/chosen.yaml for more info.
> +    type: boolean
> +
>    msi-map:
>      $ref: /schemas/types.yaml#/definitions/uint32-matrix
>      items:
> -- 
> 2.25.1
>