Re: [PATCH 3/8] usb: dwc3: core: Skip setting event buffers for host only controllers

[Krishna Kurapati PSSNV]

On 3/13/2023 7:37 AM, Dongliang Mu wrote:
> On Sat, Mar 11, 2023 at 12:40 AM Krishna Kurapati
> <quic_kriskura@xxxxxxxxxxx> wrote:
> > On some SoC's like SA8295P where the teritiary controller is host-only
> > capable, GEVTADDRHI/LO, GEVTSIZ, GEVTCOUNT registers are not accessible.
> > Trying to setup them up during core_init leads to a crash.
> >
> > For DRD/Peripheral supported controllers, event buffer setup is done
> > again in gadget_pullup. Skip setup or cleanup of event buffers if
> > controller is host-only capable.
> >
> > Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
> > ---
> >   drivers/usb/dwc3/core.c | 20 ++++++++++++++------
> >   1 file changed, 14 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index 076c0f8a4441..1ca9fa40a66e 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -840,7 +840,11 @@ static void dwc3_clk_disable(struct dwc3 *dwc)
> >
> >   static void dwc3_core_exit(struct dwc3 *dwc)
> >   {
> > -       dwc3_event_buffers_cleanup(dwc);
> > +       unsigned int    hw_mode;
> > +
> > +       hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
> > +       if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST)
> > +               dwc3_event_buffers_cleanup(dwc);
>
> quick question about dwc3_event_buffers_cleanup, there are other
> similar sites calling this function.
>
> C symbol: dwc3_event_buffers_cleanup
>
>    File   Function                   Line
> 0 core.h <global>                   1546 void
> dwc3_event_buffers_cleanup(struct dwc3 *dwc);
> 1 core.c __dwc3_set_mode             152 dwc3_event_buffers_cleanup(dwc);
> 2 core.c dwc3_event_buffers_cleanup  522 void
> dwc3_event_buffers_cleanup(struct dwc3 *dwc)
> 3 core.c dwc3_core_exit              842 dwc3_event_buffers_cleanup(dwc);
> 4 core.c dwc3_probe                 1936 dwc3_event_buffers_cleanup(dwc);
> 5 drd.c  dwc3_otg_update             363 dwc3_event_buffers_cleanup(dwc);
> 6 drd.c  dwc3_drd_exit               607 dwc3_event_buffers_cleanup(dwc);
>
> For 1, 5, and 6, any need to take care of this situation?
Hi Dongliang,

  Thanks for the review.
In the other places mentioned like set_mode otg_update or drd_exit, 
cleanup is called if we are in device mode and we want to exit that 
mode. Since for MP, we have a host only controller those paths won't be 
accessed I believe.

Regards,
Krishna,
> >          usb_phy_set_suspend(dwc->usb2_phy, 1);
> >          usb_phy_set_suspend(dwc->usb3_phy, 1);
> > @@ -1177,10 +1181,12 @@ static int dwc3_core_init(struct dwc3 *dwc)
> >          if (ret < 0)
> >                  goto err3;
> >
> > -       ret = dwc3_event_buffers_setup(dwc);
> > -       if (ret) {
> > -               dev_err(dwc->dev, "failed to setup event buffers\n");
> > -               goto err4;
> > +       if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST) {
> > +               ret = dwc3_event_buffers_setup(dwc);
> > +               if (ret) {
> > +                       dev_err(dwc->dev, "failed to setup event buffers\n");
> > +                       goto err4;
> > +               }
> >          }
> >
> >          /*
> > @@ -2008,7 +2014,9 @@ static int dwc3_probe(struct platform_device *pdev)
> >
> >   err5:
> >          dwc3_debugfs_exit(dwc);
> > -       dwc3_event_buffers_cleanup(dwc);
> > +
> > +       if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST)
> > +               dwc3_event_buffers_cleanup(dwc);
> >
> >          usb_phy_set_suspend(dwc->usb2_phy, 1);
> >          usb_phy_set_suspend(dwc->usb3_phy, 1);
> > --
> > 2.39.0