From patchwork Wed Mar 9 14:22:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mao Jinlong X-Patchwork-Id: 12775153 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7E2BBC433F5 for ; Wed, 9 Mar 2022 14:24:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:CC :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=gbrWSyxec+m2h2yWoglVYBTz72+93cFJv4AK1lcHkyA=; b=iHJtU3EAeTXToH w7ro100uiynoDA7a89lFfAh1pA85bqveF1s4APhbwiLBG4qwGWfYElmxdo/hNy+pCpR0AiILqkiXU J4sOlnKLfbGGh5FLfI8pYfMoTHvQ+QCVP6AHaApi8Zstou/tvLTNPpgHAcmDm16SgzyUAo4q0SKj1 m2HOySi5kvIrItXtwx+1oz0Bzt31l0KjvO40PMGdt5gV3p8H9VPIud1qiGCZhjksMU40LajTX2hbV ULcsVIOCRmODgZeqs/DT1WgGEwhLXBBGkdfTyPPpCFTasYEZGQixmPTmqDy3IFiRldFoTr+lOUQOC 0cY7DhKg2szfx2MNVQzQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRxCy-008x0J-Hf; Wed, 09 Mar 2022 14:22:32 +0000 Received: from alexa-out.qualcomm.com ([129.46.98.28]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRxCs-008wyv-0i for linux-arm-kernel@lists.infradead.org; Wed, 09 Mar 2022 14:22:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1646835746; x=1678371746; h=from:to:cc:subject:date:message-id:mime-version; bh=utZudFEG5bj1HKs2HiMq3ks1vgQFbEKEBct6iAdjyKU=; b=nvndSKtqt3OoRNINKht7S2zBN1Q9ps74DVSkiRt8RCfCWwhnv55NqbkO wkBe8BYNaNSiZKuGekTeVb5+GgRbkB+b9JVPMI3+6hSmLsdknmremH2aE 0kgeMvssQpN1tnvsMB65gGqSyCDgnQHX4VJh6KTGPLeV9M4KkME4DtVJ/ g=; Received: from ironmsg07-lv.qualcomm.com ([10.47.202.151]) by alexa-out.qualcomm.com with ESMTP; 09 Mar 2022 06:22:23 -0800 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg07-lv.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Mar 2022 06:22:23 -0800 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 15.2.986.15; Wed, 9 Mar 2022 06:22:22 -0800 Received: from hu-jinlmao-lv.qualcomm.com (10.49.16.6) 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 15.2.986.15; Wed, 9 Mar 2022 06:22:22 -0800 From: Mao Jinlong To: Mathieu Poirier , Suzuki K Poulose , Mike Leach , Leo Yan , Alexander Shishkin CC: Mao Jinlong , , , , , Tingwei Zhang , Yuanfang Zhang , Tao Zhang , Hao Zhang Subject: [PATCH v3] coresight: core: Fix coresight device probe failure issue Date: Wed, 9 Mar 2022 06:22:06 -0800 Message-ID: <20220309142206.15632-1-quic_jinlmao@quicinc.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.49.16.6] X-ClientProxiedBy: nalasex01c.na.qualcomm.com (10.47.97.35) To nalasex01a.na.qualcomm.com (10.47.209.196) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220309_062226_156368_4216A353 X-CRM114-Status: GOOD ( 18.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org It is possibe that probe failure issue happens when the device and its child_device's probe happens at the same time. In coresight_make_links, has_conns_grp is true for parent, but has_conns_grp is false for child device as has_conns_grp is set to true in coresight_create_conns_sysfs_group. The probe of parent device will fail at this condition. Add has_conns_grp check for child device before make the links and make the process from device_register to connection_create be atomic to avoid this probe failure issue. Suggested-by: Suzuki K Poulose Suggested-by: Mike Leach Signed-off-by: Mao Jinlong --- drivers/hwtracing/coresight/coresight-core.c | 33 +++++++++++++------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 88653d1c06a4..7fed6e9c0ca1 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -1382,7 +1382,7 @@ static int coresight_fixup_device_conns(struct coresight_device *csdev) continue; conn->child_dev = coresight_find_csdev_by_fwnode(conn->child_fwnode); - if (conn->child_dev) { + if (conn->child_dev && conn->child_dev->has_conns_grp) { ret = coresight_make_links(csdev, conn, conn->child_dev); if (ret) @@ -1574,6 +1574,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) int nr_refcnts = 1; atomic_t *refcnts = NULL; struct coresight_device *csdev; + bool registered = false; csdev = kzalloc(sizeof(*csdev), GFP_KERNEL); if (!csdev) { @@ -1594,7 +1595,8 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL); if (!refcnts) { ret = -ENOMEM; - goto err_free_csdev; + kfree(csdev); + goto err_out; } csdev->refcnt = refcnts; @@ -1619,6 +1621,13 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) csdev->dev.fwnode = fwnode_handle_get(dev_fwnode(desc->dev)); dev_set_name(&csdev->dev, "%s", desc->name); + /* + * Make sure the device registration and the connection fixup + * are synchronised, so that we don't see uninitialised devices + * on the coresight bus while trying to resolve the connections. + */ + mutex_lock(&coresight_mutex); + ret = device_register(&csdev->dev); if (ret) { put_device(&csdev->dev); @@ -1626,7 +1635,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) * All resources are free'd explicitly via * coresight_device_release(), triggered from put_device(). */ - goto err_out; + goto out_unlock; } if (csdev->type == CORESIGHT_DEV_TYPE_SINK || @@ -1641,11 +1650,11 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) * from put_device(), which is in turn called from * function device_unregister(). */ - goto err_out; + goto out_unlock; } } - - mutex_lock(&coresight_mutex); + /* Device is now registered */ + registered = true; ret = coresight_create_conns_sysfs_group(csdev); if (!ret) @@ -1655,16 +1664,18 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) if (!ret && cti_assoc_ops && cti_assoc_ops->add) cti_assoc_ops->add(csdev); +out_unlock: mutex_unlock(&coresight_mutex); - if (ret) { + /* Success */ + if (!ret) + return csdev; + + /* Unregister the device if needed */ + if (registered) { coresight_unregister(csdev); return ERR_PTR(ret); } - return csdev; - -err_free_csdev: - kfree(csdev); err_out: /* Cleanup the connection information */ coresight_release_platform_data(NULL, desc->pdata);