Re: [RFC PATCH v2 3/3] usb: dwc3: Issue core soft reset before enabling run/stop

Jung Daehwan
2022-02-17T09:46:23Z

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On Thu, Feb 17, 2022 at 02:52:14PM +0900, Jung Daehwan wrote:
> Hi wesley,
>
> On Tue, Feb 15, 2022 at 04:08:35PM -0800, Wesley Cheng wrote:
> > It is recommended by the Synopsis databook to issue a DCTL.CSftReset
> > when reconnecting from a device-initiated disconnect routine. This
> > resolves issues with enumeration during fast composition switching
> > cases, which result in an unknown device on the host.
> >
> > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
> > ---
> > drivers/usb/dwc3/core.c | 4 +---
> > drivers/usb/dwc3/core.h | 2 ++
> > drivers/usb/dwc3/gadget.c | 11 +++++++++++
> > 3 files changed, 14 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index 18adddfba3da..02d10e1cb774 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -115,8 +115,6 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
> > dwc->current_dr_role = mode;
> > }
> >
> > -static int dwc3_core_soft_reset(struct dwc3 *dwc);
> > -
> > static void __dwc3_set_mode(struct work_struct *work)
> > {
> > struct dwc3 *dwc = work_to_dwc(work);
> > @@ -261,7 +259,7 @@ u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type)
> > * dwc3_core_soft_reset - Issues core soft reset and PHY reset
> > * @dwc: pointer to our context structure
> > */
> > -static int dwc3_core_soft_reset(struct dwc3 *dwc)
> > +int dwc3_core_soft_reset(struct dwc3 *dwc)
> > {
> > u32 reg;
> > int retries = 1000;
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index 00348d6d479b..b27ad8dad317 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -1532,6 +1532,8 @@ bool dwc3_has_imod(struct dwc3 *dwc);
> > int dwc3_event_buffers_setup(struct dwc3 *dwc);
> > void dwc3_event_buffers_cleanup(struct dwc3 *dwc);
> >
> > +int dwc3_core_soft_reset(struct dwc3 *dwc);
> > +
> > #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
> > int dwc3_host_init(struct dwc3 *dwc);
> > void dwc3_host_exit(struct dwc3 *dwc);
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 0c89baedf220..788889f924f9 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -2585,6 +2585,17 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
> > dwc->ev_buf->length;
> > }
> > } else {
> > + /*
> > + * In the Synopsis DesignWare Cores USB3 Databook Rev. 1.90a
> > + * Section 4.1.9, it specifies that for a reconnect after a
> > + * device-initiated disconnect requires a core soft reset
> > + * (DCTL.CSftRst) before enabling the run/stop bit.
> > + */
> > + spin_unlock_irqrestore(&dwc->lock, flags);
> > + dwc3_core_soft_reset(dwc);
> > + spin_lock_irqsave(&dwc->lock, flags);
> > +
> > + dwc3_event_buffers_setup(dwc);
>
> Could you tell me why you add dwc3_event_buffer_setup?
>
> Best Regards,
> Jung Daehwan
>

I'm sorry I misunderstood databook then. It seems to be needed.

Best Regrards,
Jung Daehwan

> > __dwc3_gadget_start(dwc);
> > }
> >
> >

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