Re: [PATCH v2 1/2] dt-bindings: firmware: arm,scmi: Document arm,poll-transport property

[Krzysztof Kozlowski <krzk@kernel.org>]

On Wed, Dec 31, 2025 at 10:29:18PM +0100, Marek Vasut wrote:
> Document new property arm,poll-transport, which sets all SCMI operation into

Please wrap commit message according to Linux coding style / submission
process (neither too early nor over the limit):
https://elixir.bootlin.com/linux/v6.4-rc1/source/Documentation/process/submitting-patches.rst#L597

> poll mode. This is meant to work around uncooperative SCP implementations,
> which do not generate completion interrupts. This applies primarily on mbox
> shmem based implementations.
> 
> With this property set, such implementations which do not generate interrupts
> can be interacted with, until they are fixed to generate interrupts properly.
> 
> Note that, because the original base protocol exchange also requires some
> sort of completion mechanism, it is not possible to query SCMI itself for
> this property and it must be described in DT. While this does look a bit
> like policy, the SCMI provider is part of the hardware, hence DT.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Cristian Marussi <cristian.marussi@arm.com>
> Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: arm-scmi@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: s@mean@&t and limit poll transport to mailbox/shmem only
> ---
>  .../devicetree/bindings/firmware/arm,scmi.yaml         | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> index be817fd9cc34b..f4bf4173c5c7e 100644
> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> @@ -146,6 +146,13 @@ properties:
>        this platform. If set, the value should be non-zero.
>      minimum: 1
>  
> +  arm,poll-transport:
> +    type: boolean
> +    description:
> +      An optional property which unconditionally forces polling in all transports.
> +      This is mainly meant to work around uncooperative SCP, which does not generate

Also not wrapped.

Anyway, you described the desired Linux feature or behavior, not the
actual hardware. The bindings are about the latter, so instead you need
to rephrase the property and its description to match actual hardware
capabilities/features/configuration etc.


Best regards,
Krzysztof