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. Thanks & Regards, Tejas Joglekar
