Re: [RFC PATCH 4/4] dt-bindings: usb: Add snps,consolidate-trbs & consolidate-trbs

[Rob Herring <robh@kernel.org>]

On Fri, Dec 20, 2019 at 07:10:24PM +0530, Tejas Joglekar wrote:
> This commit adds the documentation for consolidate-trbs, and
> snps,consolidate-trbs property. These when set enables the quirk for
> XHCI driver for consolidation of TRB's when small buffer sizes are
> scattered over the TRB cache not making up to MPS or total transfer size
> with Synopsys xHC.
> 
> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
> ---
>  Documentation/devicetree/bindings/usb/dwc3.txt     | 6 ++++++
>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 +
>  2 files changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> index 66780a47ad85..9851da41a442 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> @@ -101,6 +101,12 @@ Optional properties:
>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>  			enable periodic ESS TX threshold.
> + - snps,consolidate-trbs: enable TRBs consolidation - host mode only. Set this
> +			to valid then for Synopsys xHC the TRBs would be
> +			consolidated to at least MPS in order to prevent the
> +			controller getting hang due to small buffer sizes which
> +			does not make up to MPS size or total transfer size
> +			across TRB cache.

Why not just always enable this?

Otherwise, this should be implied by the compatible string.

>  
>   - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>   - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> index 3f378951d624..be8d5e6a6333 100644
> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> @@ -43,6 +43,7 @@ Optional properties:
>    - quirk-broken-port-ped: set if the controller has broken port disable mechanism
>    - imod-interval-ns: default interrupt moderation interval is 5000ns
>    - phys : see usb-hcd.yaml in the current directory
> +  - consolidate-trbs: indicate if you need to consolidate trbs
>  
>  additionally the properties from usb-hcd.yaml (in the current directory) are
>  supported.
> -- 
> 2.11.0
>