Hi John,
Am 17.11.2016 um 00:47 schrieb John Youn:
> Add the "snps,ahb-burst" binding and read it in.
>
> This property controls which burst type to perform on the AHB bus as a
> master in internal DMA mode. This overrides the legacy param value,
> which we need to keep around for now since several platforms use it.
>
> Some platforms may see better or worse performance based on this
> value. The HAPS platform is one example where all INCRx have worse
> performance than INCR.
>
> Other platforms (such as the Canyonlands board) report that the default
> value causes system hangs.
>
> Signed-off-by: John Youn <johnyoun@xxxxxxxxxxxx>
> Cc: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/usb/dwc2.txt | 2 +
> drivers/usb/dwc2/core.h | 9 +++++
> drivers/usb/dwc2/params.c | 56 ++++++++++++++++++++++++++
> 3 files changed, 67 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt
> index 6c7c2bce..9e7b4b4 100644
> --- a/Documentation/devicetree/bindings/usb/dwc2.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc2.txt
according to Documentation/devicetree/bindings/submitting-patches.txt
this change should be a separate patch.
> @@ -26,6 +26,8 @@ Optional properties:
> Refer to phy/phy-bindings.txt for generic phy consumer properties
> - dr_mode: shall be one of "host", "peripheral" and "otg"
> Refer to usb/generic.txt
> +- snps,ahb-burst: specifies the ahb burst length. Valid arguments are:
> + "SINGLE", "INCR", "INCR4", "INCR8", "INCR16". Defaults to "INCR4".
This doesn't apply in case of the bcm2835. I would prefer this option is
ignored in that case with a dev_warn("snps,ahb-burst is not supported on
this platform").
Stefan
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