Re: [PATCH v8 2/3] usb: dwc2: assert phy reset when waking up in rk3288 platform

[Randy Li]

On 10/20/2016 06:58 AM, John Youn wrote:
> On 10/15/2016 8:07 AM, éè wrote:
> > 2016-09-25 2:50 GMT+08:00 Randy Li <ayaka@xxxxxxxxxxx>:
> > > On the rk3288 USB host-only port (the one that's not the OTG-enabled
> > > port) the PHY can get into a bad state when a wakeup is asserted (not
> > > just a wakeup from full system suspend but also a wakeup from
> > > autosuspend).
> > >
> > > We can get the PHY out of its bad state by asserting its "port reset",
> > > but unfortunately that seems to assert a reset onto the USB bus so it
> > > could confuse things if we don't actually deenumerate / reenumerate the
> > > device.
> > >
> > > We can also get the PHY out of its bad state by fully resetting it using
> > > the reset from the CRU (clock reset unit) in chip, which does a more full
> > > reset.  The CRU-based reset appears to actually cause devices on the bus
> > > to be removed and reinserted, which fixes the problem (albeit in a hacky
> > > way).
> > >
> > > It's unfortunate that we need to do a full re-enumeration of devices at
> > > wakeup time, but this is better than alternative of letting the bus get
> > > wedged.
> > >
> > > Signed-off-by: Randy Li <ayaka@xxxxxxxxxxx>
> > > ---
> > >  drivers/usb/dwc2/core_intr.c | 11 +++++++++++
> > >  1 file changed, 11 insertions(+)
> > >
> > > diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
> > > index d85c5c9..af27edc 100644
> > > --- a/drivers/usb/dwc2/core_intr.c
> > > +++ b/drivers/usb/dwc2/core_intr.c
> > > @@ -345,6 +345,7 @@ static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
> > >  static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
> > >  {
> > >         int ret;
> > > +       struct device_node *np = hsotg->dev->of_node;
> > >
> > >         /* Clear interrupt */
> > >         dwc2_writel(GINTSTS_WKUPINT, hsotg->regs + GINTSTS);
> > > @@ -379,6 +380,16 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
> > >                         /* Restart the Phy Clock */
> > >                         pcgcctl &= ~PCGCTL_STOPPCLK;
> > >                         dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
> > > +
> > > +                       /*
> > > +                        * It is a quirk in Rockchip RK3288, causing by
> > > +                        * a hardware bug. This will propagate out and
> > > +                        * eventually we'll re-enumerate the device.
> > > +                        * Not great but the best we can do.
> > > +                        */
> > > +                       if (of_device_is_compatible(np, "rockchip,rk3288-usb"))
> > > +                               phy_reset(hsotg->phy);
> >
> > It will call mutex_lock in phy_reset.
> >
> >
> > > +
> > >                         mod_timer(&hsotg->wkp_timer,
> > >                                   jiffies + msecs_to_jiffies(71));
> > >                 } else {
> > > --
> > > 2.7.4
> >
> > What is the status of this patchï
> > Sleeping calls(phy_reset ==> mutex) shouldn't be used in irq handler.
> > Randy will correct thatï
>
> Yes, that's right, I missed that.
>
> It will have to be fixed.
I am still thinking a method to instead it.
> Regards,
> John

--
Randy Li
The third produce department
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