Subject: Re: [PATCH net-next 1/2] dt-bindings: net: snps,dwmac: Time Based Scheduling

From: Rob Herring <[email-masked]>
Date: Thu, 28 Sep 2023 13:09:42 -0500

On Wed, Sep 27, 2023 at 09:09:18PM +0800, Rohan G Thomas wrote:
> Add new property tbs-enabled to enable Time Based Scheduling(TBS)

That's not the property you added.

> support per Tx queues. TBS feature can be enabled later using ETF
> qdisc but for only those queues that have TBS support enabled.

This property defines capable or enabled? 

Seems like OS configuration and policy.

Doesn't eh DWMAC have capability registers for supported features? Or 
did they forget per queue capabilities?

> 
> Commit 7eadf57290ec ("net: stmmac: pci: Enable TBS on GMAC5 IPK PCI
> entry") enables similar support from the stmmac pci driver.

Why does unconditionally enabling TBS work there, but not here?

> 
> Signed-off-by: Rohan G Thomas <[email-masked]>
> ---
>  Documentation/devicetree/bindings/net/snps,dwmac.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> index 5c2769dc689a..db1eb0997602 100644
> --- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> +++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> @@ -399,6 +399,14 @@ properties:
>              type: boolean
>              description: TX checksum offload is unsupported by the TX queue.
>  
> +          snps,tbs-enabled:
> +            type: boolean
> +            description:
> +              Enable Time Based Scheduling(TBS) support for the TX queue. TSO and
> +              TBS cannot be supported by a queue at the same time. If TSO support
> +              is enabled, then default TX queue 0 for TSO and in that case don't
> +              enable TX queue 0 for TBS.
> +
>          allOf:
>            - if:
>                required:
> -- 
> 2.26.2
>