From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758904AbcIHSJr (ORCPT ); Thu, 8 Sep 2016 14:09:47 -0400 Received: from us01smtprelay-2.synopsys.com ([198.182.60.111]:60619 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758849AbcIHSJf (ORCPT ); Thu, 8 Sep 2016 14:09:35 -0400 Subject: Re: [PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform To: Randy Li , "linux-usb@vger.kernel.org" References: <1473344836-26707-1-git-send-email-ayaka@soulik.info> <1473344836-26707-4-git-send-email-ayaka@soulik.info> CC: "John.Youn@synopsys.com" , "kishon@ti.com" , "felipe.balbi@linux.intel.com" , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "heiko@sntech.de" , "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "linux-rockchip@lists.infradead.org" , "robh+dt@kernel.org" , "randy.li@rock-chips.com" From: John Youn Message-ID: <80dc63ab-d27b-017a-c0e5-c0b192880cc1@synopsys.com> Date: Thu, 8 Sep 2016 11:09:17 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1473344836-26707-4-git-send-email-ayaka@soulik.info> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.9.139.118] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/8/2016 7:27 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 | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c > index d85c5c9..5b9b671 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 +380,16 @@ 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 Hi Randy, Please run ./scripts/checkpatch.pl on your patches and fix trailing whitespace in above two lines. Thanks, John