From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964894AbdALAWs (ORCPT ); Wed, 11 Jan 2017 19:22:48 -0500 Received: from mail-pf0-f176.google.com ([209.85.192.176]:35887 "EHLO mail-pf0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934963AbdALAWL (ORCPT ); Wed, 11 Jan 2017 19:22:11 -0500 From: John Stultz To: lkml Cc: John Stultz , Wei Xu , Guodong Xu , Amit Pundir , Rob Herring , John Youn , Douglas Anderson , Chen Yu , Vardan Mikayelyan , Kishon Vijay Abraham I , Felipe Balbi , Greg Kroah-Hartman , linux-usb@vger.kernel.org Subject: [PATCH 2/4 v3] usb: dwc2: Workaround case where GOTGCTL state is wrong Date: Wed, 11 Jan 2017 16:22:02 -0800 Message-Id: <1484180524-4087-3-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1484180524-4087-1-git-send-email-john.stultz@linaro.org> References: <1484180524-4087-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When removing a USB-A to USB-otg adapter cable, we get a change status irq, and then in dwc2_conn_id_status_change, we erroniously see the GOTGCTL_CONID_B flag set. This causes us to get stuck in the "while (!dwc2_is_device_mode(hsotg))" loop, spitting out "Waiting for Peripheral Mode, Mode=Host" warnings until it fails out many seconds later. This patch works around the issue by re-reading the GOTGCTL state to check if the GOTGCTL_CONID_B is still set and if not restarting the change status logic. I suspect this isn't the best solution, but it seems to work well for me. Feedback would be greatly appreciated! Cc: Wei Xu Cc: Guodong Xu Cc: Amit Pundir Cc: Rob Herring Cc: John Youn Cc: Douglas Anderson Cc: Chen Yu Cc: Vardan Mikayelyan Cc: Kishon Vijay Abraham I Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org Acked-by: John Youn Reviewed-by: Vardan Mikayelyan Signed-off-by: John Stultz --- v2: Rework goto logic suggested by Vardan, and add a comment v3: * Rebased to synopsys-usb/next branch --- drivers/usb/dwc2/hcd.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index b63b14f..888923c 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -3238,6 +3238,14 @@ static void dwc2_conn_id_status_change(struct work_struct *work) dwc2_is_host_mode(hsotg) ? "Host" : "Peripheral"); usleep_range(20000, 40000); + /* + * Sometimes the initial GOTGCTRL read is wrong, so + * check it again and jump to host mode if that was + * the case. + */ + gotgctl = dwc2_readl(hsotg->regs + GOTGCTL); + if (!(gotgctl & GOTGCTL_CONID_B)) + goto host; if (++count > 250) break; } @@ -3252,6 +3260,7 @@ static void dwc2_conn_id_status_change(struct work_struct *work) spin_unlock_irqrestore(&hsotg->lock, flags); dwc2_hsotg_core_connect(hsotg); } else { +host: /* A-Device connector (Host Mode) */ dev_dbg(hsotg->dev, "connId A\n"); while (!dwc2_is_host_mode(hsotg)) { -- 2.7.4