On 16.4.2020 19.37, Tejas Joglekar wrote: > Hi, > On 4/16/2020 1:52 PM, Felipe Balbi wrote: >> >> Hi, >> >> Tejas Joglekar <Tejas.Joglekar@xxxxxxxxxxxx> writes: >>> Hi, >>> On 4/5/2020 7:15 AM, Rob Herring wrote: >>>> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote: >>>>> This commit adds the documentation for consolidate-sgl, and >>>>> snps,consolidate-sgl property. These when set enables the quirk for >>>>> XHCI driver for consolidation of sg list into a temporary buffer when small >>>>> buffer sizes are scattered over the sg list not making up to MPS or total >>>>> transfer size within TRB cache size with Synopsys xHC. >>>>> >>>>> Signed-off-by: Tejas Joglekar <joglekar@xxxxxxxxxxxx> >>>>> --- >>>>> Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ >>>>> Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++ >>>>> 2 files changed, 6 insertions(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt >>>>> index 9946ff9ba735..292d1f7969e4 100644 >>>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt >>>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt >>>>> @@ -104,6 +104,9 @@ 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-sgl: enable sg list consolidation - host mode only. Set to use >>>>> + SG buffers of at least MPS size by consolidating smaller SG >>>>> + buffers list into a single buffer. >>>> >>>> The preference is not to keep adding properties for every single quirk >>>> or feature. These should be implied by specific compatibles. As Synopsys >>>> knows what quirks/errata/features are in each version of IP, the >>>> compatible strings should reflect those versions. (And yes, I'm sure >>>> there's customer ECO fixes that aren't reflected in the version, but >>>> that's why we have SoC specific compatibles too.) This is the only way >>>> we can fix quirks in the OS without doing DT updates. For comparison, do >>>> you want to have to update your PC BIOS so an OS can work-around issues? >>>> >>> Yes, I understand what you want to say here. But I think this compatible string >>> does not work with the platform drivers with PCI based systems. So based on the vendor >>> id and device id then I need to set the quirk required. >>> >>> @Felipe: What do you suggest for setting up quirk without the DT update for dwc3? >> >> We have been using Synopsys controller's revision register, but that's >> not visible to xhci driver and we don't have a separate compatible for >> each synopsys version on the xhci driver side. One option would be to >> add "snps,xhci-foo-bar" to xhci-plat and use that. >> > @Felipe: Thanks for suggestion > > @Mathias: Do you prefer parameter passed this way? I can send the v2 patch set, > after your input. should work, I don't see any issues with that. -Mathias
