On Mon 25 Jan 22:32 CST 2021, Wesley Cheng wrote: > On 1/25/2021 5:55 PM, Bjorn Andersson wrote: > > On Mon 25 Jan 19:14 CST 2021, Wesley Cheng wrote: > > > >> > >> > >> On 1/22/2021 9:12 AM, Bjorn Andersson wrote: > >>> On Thu 21 Jan 22:01 CST 2021, Wesley Cheng wrote: > >>> > >> > >> Hi Bjorn, > >>> > >>> Under what circumstances should we specify this? And in particular are > >>> there scenarios (in the Qualcomm platforms) where this must not be set? > >>> The TXFIFO dynamic allocation is actually a feature within the DWC3 > >> controller, and isn't specifically for QCOM based platforms. It won't > >> do any harm functionally if this flag is not set, as this is meant for > >> enhancing performance/bandwidth. > >> > >>> In particular, the composition can be changed in runtime, so should we > >>> set this for all Qualcomm platforms? > >>> > >> Ideally yes, if we want to increase bandwith for situations where SS > >> endpoint bursting is set to a higher value. > >> > >>> And if that's the case, can we not just set it from the qcom driver? > >>> > >> Since this is a common DWC3 core feature, I think it would make more > >> sense to have it in DWC3 core instead of a vendor's DWC3 glue driver. > >> > > > > I don't have any objections to implementing it in the core driver, but > > my question is can we just skip the DT binding and just enable it from > > the vendor driver? > > > > Regards, > > Bjorn > > > > Hi Bjorn, > > I see. I think there are some designs which don't have a DWC3 glue > driver, so assuming there may be other platforms using this, there may > not always be a vendor driver to set this. > You mean that there are implementations of dwc3 without an associated glue driver that haven't yet realized that they need this feature? I would suggest then that we implement the core code necessary, we enable it from the Qualcomm glue layer and when someone realize that they need this without a glue driver it's going to be trivial to add the DT binding. The alternative is that we're lugging around a requirement to specify this property in all past, present and future Qualcomm dts files - and then we'll need to hard code it for ACPI anyways. Regards, Bjorn
