From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Youn Subject: Re: [PATCH 1/2] usb: dwc2: optionally assert phy "full reset" when waking up Date: Mon, 15 Aug 2016 15:19:13 -0700 Message-ID: <38019f37-8d68-b7c1-a5b1-b34ffbadf461@synopsys.com> References: <1446236275-12698-2-git-send-email-dianders@chromium.org> <1468929933-6971-1-git-send-email-randy.li@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1468929933-6971-1-git-send-email-randy.li-TNX95d0MmH7DzftRWevZcw@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Randy Li , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" Cc: "John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org" , "gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org" , "robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "mark.rutland-5wv7dgnIgG8@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "ayaka-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org" , "eddie.cai-TNX95d0MmH7DzftRWevZcw@public.gmane.org" List-Id: devicetree@vger.kernel.org On 7/19/2016 5:06 AM, Randy Li wrote: > From: Doug Anderson > > On the rk3288 USB host-only port (the one that's not the OTG-enabled > port) the PHY can get into a bad state when a wakeup is asserted (not > just a wakeup from full system suspend but also a wakeup from > autosuspend). The problem is caused by a design fault in IC, Rockchip > have confirmed it and fix this problem in the future IC model. > > We can get the PHY out of its bad state by asserting its "port reset", > but unfortunately that seems to assert a reset onto the USB bus so it > could confuse things if we don't actually deenumerate / reenumerate the > device. > > We can also get the PHY out of its bad state by fully resetting it using > the reset from the CRU (clock reset unit), which does a more full > reset. The CRU-based reset appears to actually cause devices on the bus > to be removed and reinserted, which fixes the problem (albeit in a hacky > way). > > It's unfortunate that we need to do a full re-enumeration of devices at > wakeup time, but this is better than alternative of letting the bus get > wedged. > > Signed-off-by: Douglas Anderson > Signed-off-by: Yunzhi Li > Reviewed-by: Randy Li > --- > Documentation/devicetree/bindings/usb/dwc2.txt | 7 +++++++ > drivers/usb/dwc2/core.h | 5 +++++ > drivers/usb/dwc2/core_intr.c | 14 ++++++++++++++ > drivers/usb/dwc2/platform.c | 13 +++++++++++++ > 4 files changed, 39 insertions(+) > > diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt > index 20a68bf..40c63ae 100644 > --- a/Documentation/devicetree/bindings/usb/dwc2.txt > +++ b/Documentation/devicetree/bindings/usb/dwc2.txt > @@ -20,6 +20,13 @@ Refer to clk/clock-bindings.txt for generic clock consumer properties > Optional properties: > - phys: phy provider specifier > - phy-names: shall be "usb2-phy" > +- snps,need-phy-full-reset-on-wake: if present indicates that we need to reset > + the PHY when we detect a wakeup due to a hardware errata. If present you > + must specify a "phy-full-reset" reset. > + > +Resets: > +- phy-full-reset (optional): Fully resets the PHY (Only used by rk3288 Soc). > + > Refer to phy/phy-bindings.txt for generic phy consumer properties > - dr_mode: shall be one of "host", "peripheral" and "otg" > Refer to usb/generic.txt > diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h > index dec0b21..951abe0 100644 > --- a/drivers/usb/dwc2/core.h > +++ b/drivers/usb/dwc2/core.h > @@ -719,8 +719,11 @@ struct dwc2_hregs_backup { > * @hcd_enabled Host mode sub-driver initialization indicator. > * @gadget_enabled Peripheral mode sub-driver initialization indicator. > * @ll_hw_enabled Status of low-level hardware resources. > + * @need_phy_full_reset_on_wake: Quirk saying that we should assert > + * phy_full_reset on a remote wakeup. > * @phy: The otg phy transceiver structure for phy control. > * @uphy: The otg phy transceiver structure for old USB phy control. > + * @phy_full_reset: Reset control for the PHY's "full reset". > * @plat: The platform specific configuration data. This can be removed once > * all SoCs support usb transceiver. > * @supplies: Definition of USB power supplies > @@ -853,9 +856,11 @@ struct dwc2_hsotg { > unsigned int hcd_enabled:1; > unsigned int gadget_enabled:1; > unsigned int ll_hw_enabled:1; > + unsigned int need_phy_full_reset_on_wake:1; > > struct phy *phy; > struct usb_phy *uphy; > + struct reset_control *phy_full_reset; > struct dwc2_hsotg_plat *plat; > struct regulator_bulk_data supplies[ARRAY_SIZE(dwc2_hsotg_supply_names)]; > u32 phyif; > diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c > index d85c5c9..53d8327 100644 > --- a/drivers/usb/dwc2/core_intr.c > +++ b/drivers/usb/dwc2/core_intr.c > @@ -45,6 +45,7 @@ > #include > #include > #include > +#include > #include > > #include > @@ -379,6 +380,19 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg) > /* Restart the Phy Clock */ > pcgcctl &= ~PCGCTL_STOPPCLK; > dwc2_writel(pcgcctl, hsotg->regs + PCGCTL); > + > + /* > + * If we've got this quirk then the PHY is stuck upon > + * wakeup. Assert reset. This will propagate out and > + * eventually we'll re-enumerate the device. Not great > + * but the best we can do. > + */ > + if (hsotg->need_phy_full_reset_on_wake) { > + reset_control_assert(hsotg->phy_full_reset); > + udelay(50); > + reset_control_deassert(hsotg->phy_full_reset); > + } > + > mod_timer(&hsotg->wkp_timer, > jiffies + msecs_to_jiffies(71)); > } else { > diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c > index fc6f525..d8894a1 100644 > --- a/drivers/usb/dwc2/platform.c > +++ b/drivers/usb/dwc2/platform.c > @@ -45,6 +45,7 @@ > #include > #include > #include > +#include > > #include > > @@ -529,6 +530,18 @@ static int dwc2_driver_probe(struct platform_device *dev) > dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n", > (unsigned long)res->start, hsotg->regs); > > + hsotg->need_phy_full_reset_on_wake = > + of_property_read_bool(dev->dev.of_node, > + "snps,need-phy-full-reset-on-wake"); > + hsotg->phy_full_reset = devm_reset_control_get(hsotg->dev, > + "phy-full-reset"); > + if (IS_ERR(hsotg->phy_full_reset) && > + hsotg->need_phy_full_reset_on_wake) { Should use the devm_reset_control_get_optional() variant so that we can check whether it is a legitimate error, or the PHY is not specified or !CONFIG_OF. > + dev_warn(hsotg->dev, "Missing phy full reset (%ld); skipping\n", > + PTR_ERR(hsotg->phy_full_reset)); > + hsotg->need_phy_full_reset_on_wake = false; > + } > + Also this code can go into the dwc2_lowlevel_hw_init() function so as not to clutter up the probe() function futher. A similar patch adding a reset was submitted by Dinh which you can use as a reference: http://marc.info/?l=linux-usb&m=147085447403019&w=2 Regards, John -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html