Re: [PATCH v3 6/8] usb: dwc3: Increase DWC3 controller halt timeout

From: Thinh Nguyen
Date: Tue Aug 16 2022 - 20:34:39 EST


On 8/15/2022, Wesley Cheng wrote:
> Since EP0 transactions need to be completed before the controller halt
> sequence is finished, this may take some time depending on the host and the
> enabled functions. Increase the controller halt timeout, so that we give
> the controller sufficient time to handle EP0 transfers. Remove the need
> for making dwc3_gadget_suspend() and dwc3_gadget_resume() to be called in
> a spinlock.

Sounds like the removal of the spin_lock and the increase of halt
timeout are 2 separate change. It would be nice to separate this patch
since the $subject only indicates 1 of them.

>
> Suggested-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
> Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
> ---
> drivers/usb/dwc3/core.c | 4 ----
> drivers/usb/dwc3/gadget.c | 8 +++++++-
> 2 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index c5c238ab3083..23e123a1ab5f 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1976,9 +1976,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> case DWC3_GCTL_PRTCAP_DEVICE:
> if (pm_runtime_suspended(dwc->dev))
> break;
> - spin_lock_irqsave(&dwc->lock, flags);
> dwc3_gadget_suspend(dwc);
> - spin_unlock_irqrestore(&dwc->lock, flags);
> synchronize_irq(dwc->irq_gadget);
> dwc3_core_exit(dwc);
> break;
> @@ -2039,9 +2037,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
> return ret;
>
> dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> - spin_lock_irqsave(&dwc->lock, flags);
> dwc3_gadget_resume(dwc);
> - spin_unlock_irqrestore(&dwc->lock, flags);
> break;
> case DWC3_GCTL_PRTCAP_HOST:
> if (!PMSG_IS_AUTO(msg) && !device_can_wakeup(dwc->dev)) {
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 7b66a54250a0..b2668a83cc29 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2444,7 +2444,7 @@ static void __dwc3_gadget_set_speed(struct dwc3 *dwc)
> static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
> {
> u32 reg;
> - u32 timeout = 500;
> + u32 timeout = 100;
>
> if (pm_runtime_suspended(dwc->dev))
> return 0;
> @@ -2477,6 +2477,7 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
> dwc3_gadget_dctl_write_safe(dwc, reg);
>
> do {
> + msleep(20);

Polling interval of 20ms seems a bit much. Can we use usleep_range()
between 1-2ms?

Thanks,
Thinh

> reg = dwc3_readl(dwc->regs, DWC3_DSTS);
> reg &= DWC3_DSTS_DEVCTRLHLT;
> } while (--timeout && !(!is_on ^ !reg));
> @@ -4520,12 +4521,17 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
>
> int dwc3_gadget_suspend(struct dwc3 *dwc)
> {
> + unsigned long flags;
> +
> if (!dwc->gadget_driver)
> return 0;
>
> dwc3_gadget_run_stop(dwc, false, false);
> +
> + spin_lock_irqsave(&dwc->lock, flags);
> dwc3_disconnect_gadget(dwc);
> __dwc3_gadget_stop(dwc);
> + spin_unlock_irqrestore(&dwc->lock, flags);
>
> return 0;
> }