> From: Felipe Balbi [mailto:balbi@xxxxxx] > Sent: Friday, September 26, 2014 2:40 PM > > On Fri, Sep 26, 2014 at 08:57:19PM +0000, Paul Zimmerman wrote: > > > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > > > > index 0fcc0a3..8277065 100644 > > > > --- a/drivers/usb/dwc3/gadget.c > > > > +++ b/drivers/usb/dwc3/gadget.c > > > > @@ -2635,6 +2635,7 @@ static irqreturn_t dwc3_interrupt(int irq, void *_dwc) > > > > */ > > > > int dwc3_gadget_init(struct dwc3 *dwc) > > > > { > > > > + u32 reg; > > > > int ret; > > > > > > > > dwc->ctrl_req = dma_alloc_coherent(dwc->dev, sizeof(*dwc->ctrl_req), > > > > @@ -2689,6 +2690,13 @@ int dwc3_gadget_init(struct dwc3 *dwc) > > > > if (ret) > > > > goto err4; > > > > > > > > + if (dwc->quirks & DWC3_AMD_NL_PLAT) { > > > > + reg = dwc3_readl(dwc->regs, DWC3_DCTL); > > > > + reg |= DWC3_DCTL_LPM_ERRATA(0xf); > > > > > > weird, why would Synopsys put this here ? It seems like this is only > > > useful when LPM Errata is enabled and that's, apparently, a host-side > > > thing. > > > > > > Paul, can you comment ? > > > > These bits contribute to how the device responds to an LPM transaction > > from the host. If DCFG.LPMCap=1, they set the BESL value above which > > the core will send a NYET. If DCFG.LPMCap=0, they have no effect. So > > it's definitely a device-side thing, but only if the core is configured > > with LPM Errata support enabled. > > right, and how can SW detect if LPM Errata was enabled ? From the host > point of view, we can check bit 20 of xHCI capability register. What > about device ? I can't seem to find anything :-s I just talked to one of our RTL designers. You're right, there is no way to tell from the Device registers alone whether the controller is configured with LPM Errata support or not. You can tell for sure if it is *not* enabled, by checking GSNPSID, and if the version is earlier than 2.40a, the feature wasn't available. So for Device-mode only controllers, I guess you will need a DT property for this. -- Paul -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
