On Mon, Oct 7, 2019 at 4:39 PM Jack Pham <[email protected]> wrote: > > Hi John, Yu, Felipe, > > On Mon, Oct 07, 2019 at 05:55:50PM +0000, John Stultz wrote: > > From: Yu Chen <[email protected]> > > > > A GCTL soft reset should be executed when switch mode for dwc3 core > > of Hisilicon Kirin Soc. > > > > Cc: Greg Kroah-Hartman <[email protected]> > > Cc: Felipe Balbi <[email protected]> > > Cc: Andy Shevchenko <[email protected]> > > Cc: Rob Herring <[email protected]> > > Cc: Mark Rutland <[email protected]> > > Cc: Yu Chen <[email protected]> > > Cc: Matthias Brugger <[email protected]> > > Cc: Chunfeng Yun <[email protected]> > > Cc: [email protected] > > Cc: [email protected] > > Signed-off-by: Yu Chen <[email protected]> > > Signed-off-by: John Stultz <[email protected]> > > --- > > drivers/usb/dwc3/core.c | 20 ++++++++++++++++++++ > > drivers/usb/dwc3/core.h | 3 +++ > > 2 files changed, 23 insertions(+) > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > index 999ce5e84d3c..440261432421 100644 > > --- a/drivers/usb/dwc3/core.c > > +++ b/drivers/usb/dwc3/core.c > > @@ -112,6 +112,19 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode) > > dwc->current_dr_role = mode; > > } > > > > +static void dwc3_gctl_core_soft_reset(struct dwc3 *dwc) > > +{ > > + u32 reg; > > + > > + reg = dwc3_readl(dwc->regs, DWC3_GCTL); > > + reg |= DWC3_GCTL_CORESOFTRESET; > > + dwc3_writel(dwc->regs, DWC3_GCTL, reg); > > + > > + reg = dwc3_readl(dwc->regs, DWC3_GCTL); > > + reg &= ~DWC3_GCTL_CORESOFTRESET; > > + dwc3_writel(dwc->regs, DWC3_GCTL, reg); > > +} > > + > > static void __dwc3_set_mode(struct work_struct *work) > > { > > struct dwc3 *dwc = work_to_dwc(work); > > @@ -156,6 +169,10 @@ static void __dwc3_set_mode(struct work_struct *work) > > > > dwc3_set_prtcap(dwc, dwc->desired_dr_role); > > > > + /* Execute a GCTL Core Soft Reset when switch mode */ > > + if (dwc->gctl_reset_quirk) > > + dwc3_gctl_core_soft_reset(dwc); > > + > > In fact it is mentioned in the Synopsys databook to perform a GCTL > CoreSoftReset when changing the PrtCapDir between device & host modes. > So I think this should apply generally without a quirk. Further, it > states to do this *prior* to writing PrtCapDir, so should it go before > dwc3_set_prtcap() instead?
Sounds good. I have no such access to the hardware docs, so I really appreciate your input here! I'll refactor it as you describe and remove the quirk flag. thanks -john
