On 16/03/16 15:14, Felipe Balbi wrote: > Roger Quadros <rog...@ti.com> writes: > >> [ text/plain ] >> The existing workaround of forcing DEVSPD to SUPER_SPEED >> for HIGH_SPEED ports is causing another side effect >> which causes erratic interrupts and delayed gadget >> enumeration of upto 2 seconds. >> >> Work around the run/stop issue by detecting if >> it happened using debug LTSSM state and issuing >> soft reset to the device controller when changing RUN_STOP >> from 0 to 1. >> >> We apply the workaround only if PRTCAP is DEVICE mode >> as we don't yet support this workaround in OTG mode. >> >> Use USB RESET event as exit condition for workaround. >> >> Signed-off-by: Roger Quadros <rog...@ti.com> >> --- >> drivers/usb/dwc3/core.h | 1 + >> drivers/usb/dwc3/gadget.c | 175 >> +++++++++++++++++++++++++++++++++++++--------- >> 2 files changed, 144 insertions(+), 32 deletions(-) >> >> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h >> index 2bea1ac..a724c0d 100644 >> --- a/drivers/usb/dwc3/core.h >> +++ b/drivers/usb/dwc3/core.h >> @@ -762,6 +762,7 @@ struct dwc3 { >> >> struct usb_gadget gadget; >> struct usb_gadget_driver *gadget_driver; >> + struct completion reset_event; /* used for run/stop workaround */ > > the fact that you needed a struct completion here already points to the > fact this is really, really bad :-) > >> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c >> index 3ac170f..03418b8 100644 >> --- a/drivers/usb/dwc3/gadget.c >> +++ b/drivers/usb/dwc3/gadget.c >> @@ -35,6 +35,9 @@ >> #include "gadget.h" >> #include "io.h" >> >> +static void dwc3_gadget_disable_irq(struct dwc3 *dwc); >> +static int dwc3_gadget_restart(struct dwc3 *dwc); >> + >> /** >> * dwc3_gadget_set_test_mode - Enables USB2 Test Modes >> * @dwc: pointer to our context structure >> @@ -1570,13 +1573,100 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, >> int is_on) >> struct dwc3 *dwc = gadget_to_dwc(g); >> unsigned long flags; >> int ret; >> + int trys = 0; >> >> is_on = !!is_on; >> >> + if (is_on) >> + reinit_completion(&dwc->reset_event); >> + >> spin_lock_irqsave(&dwc->lock, flags); >> ret = dwc3_gadget_run_stop(dwc, is_on, false); >> spin_unlock_irqrestore(&dwc->lock, flags); >> >> +try: >> + /** >> + * WORKAROUND: DWC3 revision < 2.20a have an issue >> + * which would cause metastability state on Run/Stop >> + * bit if we try to force the IP to USB2-only mode. >> + * >> + * Because of that, we check if we hit that issue and >> + * reset core and retry if we did. >> + * >> + * We only attempt this workaround if we are in >> + * DEVICE mode (i.e. not OTG). >> + * >> + * Refers to: >> + * >> + * STAR#9000525659: Clock Domain Crossing on DCTL in >> + * USB 2.0 Mode >> + */ >> + if (is_on && dwc->revision < DWC3_REVISION_220A && >> + dwc->prtcap_mode == DWC3_GCTL_PRTCAP_DEVICE) { >> + u32 devspd, ltssm; >> + unsigned long t; >> + >> + /* only applicable if devspd != SUPERSPEED */ >> + devspd = dwc3_readl(dwc->regs, DWC3_DCFG) & >> DWC3_DCFG_SPEED_MASK; >> + if (devspd == DWC3_DCFG_SUPERSPEED) >> + goto done; >> + >> + /* get link state */ >> + ltssm = dwc3_readl(dwc->regs, DWC3_GDBGLTSSM); >> + ltssm = (ltssm >> 22) & 0xf; >> + >> + /** >> + * Need to wait for 100ms and check if ltssm != 4 to detect >> + * metastability issue. If we got a reset event then we are >> + * safe and can continue. >> + */ >> + t = wait_for_completion_timeout(&dwc->reset_event, >> + msecs_to_jiffies(100)); >> + if (t) >> + goto done; >> + >> + /** >> + * If link state != 4 we've hit the metastability issue, soft >> reset. >> + */ >> + if (ltssm == 4) >> + goto done; >> + >> + dwc3_trace(trace_dwc3_gadget, >> + "applying metastability workaround\n"); >> + trys++; >> + if (trys == 2) { >> + dev_WARN_ONCE(dwc->dev, true, >> + "metastability workaround failed!\n"); >> + return -ETIMEDOUT; >> + } >> + >> + spin_lock_irqsave(&dwc->lock, flags); >> + /* stop gadget */ >> + dwc3_gadget_disable_irq(dwc); >> + __dwc3_gadget_ep_disable(dwc->eps[0]); >> + __dwc3_gadget_ep_disable(dwc->eps[1]); >> + >> + /* soft reset device and restart */ >> + ret = dwc3_device_reinit(dwc); >> + if (ret) { >> + dev_err(dwc->dev, "device reinit failed\n"); >> + return ret; >> + } >> + >> + reinit_completion(&dwc->reset_event); >> + /* restart gadget */ >> + ret = dwc3_gadget_restart(dwc); >> + if (ret) { >> + dev_err(dwc->dev, "failed to re-init gadget\n"); >> + return ret; >> + } >> + >> + spin_unlock_irqrestore(&dwc->lock, flags); >> + goto try; >> + } > > holy crap dude ?!? Now ->pullup() has to reinitialize dwc3 completely ? >
Only if it hits the error state. We're only re-initializing the device controller not complete dwc3. cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html