From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932241AbbJPSGH (ORCPT ); Fri, 16 Oct 2015 14:06:07 -0400 Received: from smtprelay4.synopsys.com ([198.182.47.9]:40985 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751510AbbJPSGE convert rfc822-to-8bit (ORCPT ); Fri, 16 Oct 2015 14:06:04 -0400 From: John Youn To: Douglas Anderson , John Youn , "balbi@ti.com" CC: Yunzhi Li , =?iso-8859-1?Q?Heiko_St=FCbner?= , "linux-rockchip@lists.infradead.org" , Julius Werner , "gregory.herrero@intel.com" , "yousaf.kaukab@intel.com" , "dinguyen@opensource.altera.com" , "gregkh@linuxfoundation.org" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] usb: dwc2: host: Protect PCGCTL with lock in dwc2_port_resume() Thread-Topic: [PATCH] usb: dwc2: host: Protect PCGCTL with lock in dwc2_port_resume() Thread-Index: AQHRBtPkU5MFhSGEgE21K2QjcRI1oA== Date: Fri, 16 Oct 2015 18:06:01 +0000 Message-ID: <2B3535C5ECE8B5419E3ECBE30077290901DC39AF5F@US01WEMBX2.internal.synopsys.com> References: <1444863507-27463-1-git-send-email-dianders@chromium.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.10.161.124] Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/14/2015 3:58 PM, Douglas Anderson wrote: > From code inspection, it appears to be unsafe to do a read-modify-write > of PCGCTL in dwc2_port_resume(). Let's make sure the spinlock is held > around this operation. > > Signed-off-by: Douglas Anderson > --- > drivers/usb/dwc2/hcd.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c > index af4e4a2..e79baf7 100644 > --- a/drivers/usb/dwc2/hcd.c > +++ b/drivers/usb/dwc2/hcd.c > @@ -1500,6 +1500,8 @@ static void dwc2_port_resume(struct dwc2_hsotg *hsotg) > u32 hprt0; > u32 pcgctl; > > + spin_lock_irqsave(&hsotg->lock, flags); > + > /* > * If hibernation is supported, Phy clock is already resumed > * after registers restore. > @@ -1508,10 +1510,11 @@ static void dwc2_port_resume(struct dwc2_hsotg *hsotg) > pcgctl = dwc2_readl(hsotg->regs + PCGCTL); > pcgctl &= ~PCGCTL_STOPPCLK; > dwc2_writel(pcgctl, hsotg->regs + PCGCTL); > + spin_unlock_irqrestore(&hsotg->lock, flags); > usleep_range(20000, 40000); > + spin_lock_irqsave(&hsotg->lock, flags); > } > > - spin_lock_irqsave(&hsotg->lock, flags); > hprt0 = dwc2_read_hprt0(hsotg); > hprt0 |= HPRT0_RES; > hprt0 &= ~HPRT0_SUSP; > Acked-by: John Youn John