From patchwork Thu Jul 14 04:56:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rohith Kollalsi X-Patchwork-Id: 590766 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 503CDC433EF for ; Thu, 14 Jul 2022 05:02:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235187AbiGNFCC (ORCPT ); Thu, 14 Jul 2022 01:02:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237758AbiGNE75 (ORCPT ); Thu, 14 Jul 2022 00:59:57 -0400 Received: from alexa-out-sd-01.qualcomm.com (alexa-out-sd-01.qualcomm.com [199.106.114.38]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 330441F2F3; Wed, 13 Jul 2022 21:56:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1657774600; x=1689310600; h=from:to:cc:subject:date:message-id:mime-version; bh=lo8m1CDkPXiL9g2nnCBXYZuPow5p7LgdYRNIqe9SssU=; b=VEj6W8tdTJTFMw7g9YxfsqSjv5sk5mmsBENSvtC7c7GF4RDorbmHYsEw eFRG/A6DulzW6dgHxNCxlKW5NtkgdInlWo+nTVdVwQvLtL9YelMKLxU5E O1SBs/k1uBkOBTWG2OFOWUmiDhEqYEoewUi9bwuZC01EZEyZHKB6zQrun k=; Received: from unknown (HELO ironmsg01-sd.qualcomm.com) ([10.53.140.141]) by alexa-out-sd-01.qualcomm.com with ESMTP; 13 Jul 2022 21:56:40 -0700 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg01-sd.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2022 21:56:39 -0700 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Wed, 13 Jul 2022 21:56:39 -0700 Received: from hu-rkollals-hyd.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Wed, 13 Jul 2022 21:56:36 -0700 From: Rohith Kollalsi To: Felipe Balbi , Greg Kroah-Hartman , Philipp Zabel CC: , , "Rohith Kollalsi" Subject: [PATCH v2] usb: dwc3: core: Do not perform GCTL_CORE_SOFTRESET during bootup Date: Thu, 14 Jul 2022 10:26:25 +0530 Message-ID: <20220714045625.20377-1-quic_rkollals@quicinc.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org According to the programming guide, it is recommended to perform a GCTL_CORE_SOFTRESET only when switching the mode from device to host or host to device. However, it is found that during bootup when __dwc3_set_mode() is called for the first time, GCTL_CORESOFTRESET is done with suspendable bit(BIT 17) of DWC3_GUSB3PIPECTL set. This some times leads to issues like controller going into bad state and controller registers reading value zero. Until GCTL_CORESOFTRESET is done and run/stop bit is set core initialization is not complete. Setting suspendable bit of DWC3_GUSB3PIPECTL and then performing GCTL_CORESOFTRESET is therefore not recommended. Avoid this by only performing the reset if current_dr_role is set, that is, when doing subsequent role switching. Fixes: f88359e1588b ("usb: dwc3: core: Do core softreset when switch mode") Signed-off-by: Rohith Kollalsi --- v2: Explaining the scenario in a better way in the comment before GCTL.CoreSoftReset. drivers/usb/dwc3/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 050b2ba5986d..c5c238ab3083 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -158,9 +158,13 @@ static void __dwc3_set_mode(struct work_struct *work) break; } - /* For DRD host or device mode only */ - if ((DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC31, 190A)) && - dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG) { + /* + * When current_dr_role is not set, there's no role switching. + * Only perform GCTL.CoreSoftReset when there's DRD role switching. + */ + if (dwc->current_dr_role && ((DWC3_IP_IS(DWC3) || + DWC3_VER_IS_PRIOR(DWC31, 190A)) && + dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG)) { reg = dwc3_readl(dwc->regs, DWC3_GCTL); reg |= DWC3_GCTL_CORESOFTRESET; dwc3_writel(dwc->regs, DWC3_GCTL, reg);