Re: [PATCH net-next v2 1/2] dt-bindings: net: airoha: Add EN7581 memory-region property

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On Fri, May 09, 2025 at 04:51:33PM +0200, Lorenzo Bianconi wrote:
> > Introduce the memory-region and memory-region-names properties for the
> > ethernet node available on EN7581 SoC. In order to improve performances,
> > EN7581 SoC supports allocating buffers for hw forwarding queues in SRAM
> > instead of DRAM if available on the system.
> 
> But 'reserved-memory' is generally for system memory which is DRAM 
> though we unfortunately don't enforce that. For small onchip SRAM, you 
> should be using the mmio-sram binding and the 'sram' property.

Reviewing the vendor sdk my understanding was wrong (sorry for the noise).
Here we just want to add the capability to allocate hw forwarding buffers queue
defining the memory region in the DTS instead of using dmam_alloc_coherent()
since in some configurations QDMA blocks require a contiguous block of
system memory for hwfd buffers queue.
Moreover, EN7581 SoC supports consuming SRAM instead of DRAM for hw forwarding
descriptors queue. This is managed in hw, we just need to request it in the
flowtable entry configuration.
I will fix it in v2.

Regards,
Lorenzo

> 
> > 
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  .../devicetree/bindings/net/airoha,en7581-eth.yaml          | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml b/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml
> > index 0fdd1126541774acacc783d98e4c089b2d2b85e2..6d22131ac2f9e28390b9e785ce33e8d983eafd0f 100644
> > --- a/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml
> > +++ b/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml
> > @@ -57,6 +57,16 @@ properties:
> >        - const: hsi-mac
> >        - const: xfp-mac
> >  
> > +  memory-region:
> > +    items:
> > +      - description: QDMA0 buffer memory
> > +      - description: QDMA1 buffer memory
> > +
> > +  memory-region-names:
> > +    items:
> > +      - const: qdma0-buf
> > +      - const: qdma1-buf
> > +
> >    "#address-cells":
> >      const: 1
> >  
> > @@ -140,6 +150,9 @@ examples:
> >                       <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>,
> >                       <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
> >  
> > +        memory-region = <&qdma0_buf>, <&qdma1_buf>;
> > +        memory-region-names = "qdma0-buf", "qdma1-buf";
> > +
> >          airoha,npu = <&npu>;
> >  
> >          #address-cells = <1>;
> > 
> > -- 
> > 2.49.0
> > 

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