On 1/8/2021 4:44 PM, Thinh Nguyen wrote: > Hi, > > John Stultz wrote: >> On Fri, Jan 8, 2021 at 4:26 AM Felipe Balbi <balbi@xxxxxxxxxx> wrote: >>> >>> Hi, >>> >>> John Stultz <john.stultz@xxxxxxxxxx> writes: >>>> From: Yu Chen <chenyu56@xxxxxxxxxx> >>>> >>>> Just resending this, as discussion died out a bit and I'm not >>>> sure how to make further progress. See here for debug data that >>>> was requested last time around: >>>> https://urldefense.com/v3/__https://lore.kernel.org/lkml/CALAqxLXdnaUfJKx0aN9xWwtfWVjMWigPpy2aqsNj56yvnbU80g@xxxxxxxxxxxxxx/__;!!A4F2R9G_pg!LNzuprAeg-O80SgolYkIkW4-ne-M-yLWCDUY9MygAIrQC398Z6gRJ9wnsnlqd3w$ >>>> >>>> With the current dwc3 code on the HiKey960 we often see the >>>> COREIDLE flag get stuck off in __dwc3_gadget_start(), which >>>> seems to prevent the reset irq and causes the USB gadget to >>>> fail to initialize. >>>> >>>> We had seen occasional initialization failures with older >>>> kernels but with recent 5.x era kernels it seemed to be becoming >>>> much more common, so I dug back through some older trees and >>>> realized I dropped this quirk from Yu Chen during upstreaming >>>> as I couldn't provide a proper rational for it and it didn't >>>> seem to be necessary. I now realize I was wrong. >>>> >>>> After resubmitting the quirk, Thinh Nguyen pointed out that it >>>> shouldn't be a quirk at all and it is actually mentioned in the >>>> programming guide that it should be done when switching modes >>>> in DRD. >>>> >>>> So, to avoid these !COREIDLE lockups seen on HiKey960, this >>>> patch issues GCTL soft reset when switching modes if the >>>> controller is in DRD mode. >>>> >>>> Cc: Felipe Balbi <balbi@xxxxxxxxxx> >>>> Cc: Tejas Joglekar <tejas.joglekar@xxxxxxxxxxxx> >>>> Cc: Yang Fei <fei.yang@xxxxxxxxx> >>>> Cc: YongQin Liu <yongqin.liu@xxxxxxxxxx> >>>> Cc: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx> >>>> Cc: Thinh Nguyen <thinhn@xxxxxxxxxxxx> >>>> Cc: Jun Li <lijun.kernel@xxxxxxxxx> >>>> Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> >>>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> >>>> Cc: linux-usb@xxxxxxxxxxxxxxx >>>> Signed-off-by: Yu Chen <chenyu56@xxxxxxxxxx> >>>> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> >>>> --- >>>> v2: >>>> * Rework to always call the GCTL soft reset in DRD mode, >>>> rather then using a quirk as suggested by Thinh Nguyen >>>> >>>> v3: >>>> * Move GCTL soft reset under the spinlock as suggested by >>>> Thinh Nguyen >>> Because this is such an invasive change, I would prefer that we get >>> Tested-By tags from a good fraction of the users before applying these >>> two changes. >> I'm happy to reach out to folks to try to get that. Though I'm >> wondering if it would be better to put it behind a dts quirk flag, as >> originally proposed? >> https://urldefense.com/v3/__https://lore.kernel.org/lkml/20201021181803.79650-1-john.stultz@xxxxxxxxxx/__;!!A4F2R9G_pg!LNzuprAeg-O80SgolYkIkW4-ne-M-yLWCDUY9MygAIrQC398Z6gRJ9wnRWITZfc$ >> >> That way folks can enable it for devices as they need? >> >> Again, I'm not trying to force this in as-is, just mostly sending it >> out again for discussion to understand what other approach might work. >> >> thanks >> -john > > A quirk would imply something is broken/diverged from the design right? > But it's not the case here, and at least this is needed for HiKey960. > Also, I think Rob will be ok with not adding 1 more quirk to the dwc3 > devicetree. :) > > BR, > Thinh > Hi All, Sorry for jumping in, but I checked the SNPS v1.90a databook, and that seemed to remove the requirement for the GCTL.softreset before writing to PRTCAPDIR. Should we consider adding a controller version/IP check? Thanks Wesley Cheng -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
