Re: [PATCH 2/3] dt-bindings: net: qcom,ipa: Add sram property for describing IMEM slice

[Alex Elder <elder@ieee.org>]

On 5/22/25 6:08 PM, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 
> The IPA driver currently grabs a slice of IMEM through hardcoded
> addresses. Not only is that ugly and against the principles of DT,
> but it also creates a situation where two distinct platforms
> implementing the same version of IPA would need to be hardcoded
> together and matched at runtime.
> 
> Instead, do the sane thing and accept a handle to said region directly.
> 
> Don't make it required on purpose, as a) it's not there on ancient
> implementations (currently unsupported) and we're not yet done with
> filling the data across al DTs.

We have to support "ancient" DTBs, right?  So unfortunately
the fallback can't go away.

> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Looks good.

Reviewed-by: Alex Elder <elder@riscstar.com>


> ---
>   Documentation/devicetree/bindings/net/qcom,ipa.yaml | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/qcom,ipa.yaml b/Documentation/devicetree/bindings/net/qcom,ipa.yaml
> index b4a79912d4739bec33933cdd7bb5e720eb41c814..1109f4d170af7178b998c6b7d415cc60de1c58c5 100644
> --- a/Documentation/devicetree/bindings/net/qcom,ipa.yaml
> +++ b/Documentation/devicetree/bindings/net/qcom,ipa.yaml
> @@ -166,6 +166,13 @@ properties:
>         initializing IPA hardware.  Optional, and only used when
>         Trust Zone performs early initialization.
>   
> +  sram:
> +    maxItems: 1
> +    description:
> +      A reference to an additional region residing in IMEM (special
> +      on-chip SRAM), which is accessed by the IPA firmware and needs
> +      to be IOMMU-mapped from the OS.
> +
>   required:
>     - compatible
>     - iommus
>