Re: [PATCH v2 1/5] dt-bindings: usb: snps,dwc3: Add 'snps,xhci-write-64-hi-lo-quirk' quirk

Jung Daehwan
2024-06-03T08:36:25Z

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On Mon, Jun 03, 2024 at 08:57:16AM +0200, Krzysztof Kozlowski wrote:
> On 03/06/2024 05:03, Jung Daehwan wrote:
> > On Fri, May 31, 2024 at 10:10:30AM +0200, Krzysztof Kozlowski wrote:
> >> On 31/05/2024 08:07, Daehwan Jung wrote:
> >>> Add a new quirk for dwc3 core to support writing high-low order.
> >>
> >> This does not tell me more. Could be OS property as well... please
> >> describe hardware and provide rationale why this is suitable for
> >> bindings (also cannot be deduced from compatible).
> >>
> >>
> >
> > Hi,
> >
> > I'm sorry I didn't describe it in dt-bindings patches.
> > It's described in cover-letter and other patches except in dt-bindings.
> > I will add it in next submission.
> >
> > I've found out the limitation of Synopsys dwc3 controller. This can work
> > on Host mode using xHCI. A Register related to ERST should be written
> > high-low order not low-high order. Registers are always written low-high order
> > following xHCI spec.(64-bit written is done in each 2 of 32-bit)
> > That's why new quirk is needed for workaround. This quirk is used not in
> > dwc3 controller itself, but passed to xhci quirk eventually. That's because
> > this issue occurs in Host mode using xHCI.
> >
>
> If there is only one register then you should just program it
> differently and it does not warrant quirk property.
>

Could you tell me why you think it does not warrant? I think this is
good to use quirk.

Best Regards,
Jung Deahwan

> Best regards,
> Krzysztof
>
>

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