From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Youn Subject: Re: [PATCH v7 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform Date: Tue, 6 Sep 2016 19:02:20 -0700 Message-ID: <1ac13d9d-39c4-c110-d5ab-2dee30c0b4aa@synopsys.com> References: <1472939729-15187-1-git-send-email-ayaka@soulik.info> <1472939729-15187-4-git-send-email-ayaka@soulik.info> <57CE50A2.7080502@ti.com> <31806DDB-EBF1-4839-81E1-5F7A1D236538@soulik.info> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <31806DDB-EBF1-4839-81E1-5F7A1D236538-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ayaka , John Youn Cc: Kishon Vijay Abraham I , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "felipe.balbi-VuQAYsv1563Yd54FQh9/CA@public.gmane.org" , "mark.rutland-5wv7dgnIgG8@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org" , "gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "randy.li-TNX95d0MmH7DzftRWevZcw@public.gmane.org" List-Id: devicetree@vger.kernel.org On 9/6/2016 6:19 PM, Ayaka wrote: > > > 從我的 iPad 傳送 > >> John Youn 於 2016年9月7日 上午2:54 寫道： >> >>> On 9/5/2016 10:15 PM, Kishon Vijay Abraham I wrote: >>> Hi, >>> >>>> On Sunday 04 September 2016 03:25 AM, Randy Li wrote: >>>> 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). >>>> >>>> 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) in chip, 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: Randy Li >>>> --- >>>> drivers/usb/dwc2/core_intr.c | 12 ++++++++++++ >>>> 1 file changed, 12 insertions(+) >>>> >>>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c >>>> index d85c5c9..08485b7 100644 >>>> --- a/drivers/usb/dwc2/core_intr.c >>>> +++ b/drivers/usb/dwc2/core_intr.c >>>> @@ -345,6 +345,7 @@ static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg) >>>> static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg) >>>> { >>>> int ret; >>>> + struct device_node *np = hsotg->dev->of_node; >>>> >>>> /* Clear interrupt */ >>>> dwc2_writel(GINTSTS_WKUPINT, hsotg->regs + GINTSTS); >>>> @@ -379,6 +380,17 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg) >>>> /* Restart the Phy Clock */ >>>> pcgcctl &= ~PCGCTL_STOPPCLK; >>>> dwc2_writel(pcgcctl, hsotg->regs + PCGCTL); >>>> + >>>> + /* >>>> + * It is a quirk in Rockchip RK3288, causing by >>>> + * a hardware bug. This will propagate out and >>>> + * eventually we'll re-enumerate the device. >>>> + * Not great but the best we can do >>>> + */ >>>> + if (of_device_is_compatible(np, "rockchip,rk3288-usb") >>>> + && (NULL != hsotg->phy->ops->reset)) >>>> + hsotg->phy->ops->reset(hsotg->phy); >>> >>> never call the phy ops directly from the controller driver. It has to be >>> protected as well. >> >> It looks like we should be calling an API function instead, correct? >> > Could you give me a example for the wrapper of phy ops? Check these files: * include/linux/phy/phy.h * drivers/phy/phy-core.c Search for "phy_set_mode". I'm thinking there should be a "phy_reset" API function which calls the phy->ops->reset in a similar manner. With the same runtime checks and stub function if CONFIG_GENERIC_PHY is not enabled. Regards, John -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html