From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754803AbcIFFPJ (ORCPT ); Tue, 6 Sep 2016 01:15:09 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:55605 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366AbcIFFPH (ORCPT ); Tue, 6 Sep 2016 01:15:07 -0400 Subject: Re: [PATCH v7 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform To: Randy Li , References: <1472939729-15187-1-git-send-email-ayaka@soulik.info> <1472939729-15187-4-git-send-email-ayaka@soulik.info> CC: , , , , , , , , , From: Kishon Vijay Abraham I Message-ID: <57CE50A2.7080502@ti.com> Date: Tue, 6 Sep 2016 10:44:10 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <1472939729-15187-4-git-send-email-ayaka@soulik.info> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks Kishon