From patchwork Wed Dec 20 02:52:14 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honghui Zhang X-Patchwork-Id: 10124831 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7172C6057F for ; Wed, 20 Dec 2017 02:53:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6A37929436 for ; Wed, 20 Dec 2017 02:53:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5CDA229470; Wed, 20 Dec 2017 02:53:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0C88F29436 for ; Wed, 20 Dec 2017 02:53:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject: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=rl4EstHXBhfFezU1CewEf7cn0ULkpVUYBtEDSXsQTog=; b=i0FN6/vPqPT7iY w/TZlOFahuoBZN4eUK5dJw4uUKHBnKcC5NVZV6kqaR55YAjc3idLcoeLtDaA4S4YeDjnJ6EBe4BQc g5LG/9IGYm9T2OI0W9bQnY9JSRqKBZhbkySO7DX4AvmfPLLSB24hM0t5vi45EPsDfzRLoAm8gR7qb ELXxj04FBaiZA+ByXXoALTlY2WZDlUZoE0lakaqQiSSuSfy1d8hyAT74B4+jyBg2GLsD3BJZkOIq4 oIEf2jc5SqxQ6ztW2AJz1l/gr1DPCOoIVnx7FTLdYjW9nz5gVrGlqt1RssfIApARUyTp2IZyHEFhk 1V7qbypf2ym8x6kGFiqQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.89 #1 (Red Hat Linux)) id 1eRUVV-00060s-Ev; Wed, 20 Dec 2017 02:53:21 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eRUV6-0005l8-2m; Wed, 20 Dec 2017 02:52:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:Message-ID: Date:Subject:CC:To:From:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=LGqk0IlErzXLSFk+dR8aWbWiOrDh4zZfsEKzcRJVtjI=; b=igHYHYWjIKiKRWLSwy/LtHIuz+ lGQWNKNwQXRg2tlo1SRRYYTW8f2FJQmJcPUOs4LFtetD1SAyOmQ9jwx/W8gZxD0qoU9ppKXanW9c3 bQzvWNz2Wt7ptQ4HgSwWspjq/IHX2JbgOfN2KlgFA7QjSmT7LnVOalSfXo1Nh5H3qYUj7+Ji5wmBx kvzVz88XNGIRXAiDoWQNWJwLNggX5U0sp1HdMVxw25h/Ufm7qNgMcbRsGaCeJe/ByYLAAxVCf0Yh3 VERCctuMUEfS3A1jPYY8FCp0uUQlleLfQH+r3WqZTQmMHkYaE0+kP3mtU8Lfte+Da6GNgp3Hh3STb f+zgjX+w==; Received: from [210.61.82.184] (helo=mailgw02.mediatek.com) by casper.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eRUV2-0008J5-6f; Wed, 20 Dec 2017 02:52:54 +0000 X-UUID: f774c4d34eef44e08ac9145a70fbf58f-20171220 Received: from mtkexhb01.mediatek.inc [(172.21.101.102)] by mailgw02.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 2116578516; Wed, 20 Dec 2017 10:52:19 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs01n1.mediatek.inc (172.21.101.68) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Wed, 20 Dec 2017 10:52:17 +0800 Received: from localhost.localdomain (10.17.3.153) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1210.3 via Frontend Transport; Wed, 20 Dec 2017 10:52:17 +0800 From: To: , , , , , , , , , Subject: [PATCH] PCI: Mediatek: clear irq status after irq dispathed to avoid reentry Date: Wed, 20 Dec 2017 10:52:14 +0800 Message-ID: <1513738334-26213-1-git-send-email-honghui.zhang@mediatek.com> X-Mailer: git-send-email 2.6.4 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171220_025252_503378_A0FD28DD X-CRM114-Status: GOOD ( 15.32 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: youlin.pei@mediatek.com, hongkun.cao@mediatek.com, sean.wang@mediatek.com, xinping.qian@mediatek.com, honghui.zhang@mediatek.com, yong.wu@mediatek.com Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+patchwork-linux-mediatek=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Honghui Zhang There maybe a same irq reentry scenario after irq received in current irq handle flow: EP device PCIe host driver EP driver 1. issue an irq 2. received irq 3. clear irq status 4. dispatch irq 5. clear irq source The irq status was not successfully cleared at step 2 since the irq source was not cleared yet. So the PCIe host driver may receive the same irq after step 5. Then there's an irq reentry occurred. Even worse, if the reentry irq was not an irq that EP driver expected, it may not handle the irq. Then we may run into the dead loop from step 2 to step 4. Clear the irq status after irq have been dispatched to avoid the irq reentry. Signed-off-by: Honghui Zhang Acked-by: Ryder Lee --- drivers/pci/host/pcie-mediatek.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/pci/host/pcie-mediatek.c b/drivers/pci/host/pcie-mediatek.c index db93efd..3248771 100644 --- a/drivers/pci/host/pcie-mediatek.c +++ b/drivers/pci/host/pcie-mediatek.c @@ -605,11 +605,11 @@ static irqreturn_t mtk_pcie_intr_handler(int irq, void *data) while ((status = readl(port->base + PCIE_INT_STATUS)) & INTX_MASK) { for_each_set_bit_from(bit, &status, PCI_NUM_INTX + INTX_SHIFT) { - /* Clear the INTx */ - writel(1 << bit, port->base + PCIE_INT_STATUS); virq = irq_find_mapping(port->irq_domain, bit - INTX_SHIFT); generic_handle_irq(virq); + /* Clear the INTx */ + writel(1 << bit, port->base + PCIE_INT_STATUS); } } @@ -619,10 +619,10 @@ static irqreturn_t mtk_pcie_intr_handler(int irq, void *data) while ((imsi_status = readl(port->base + PCIE_IMSI_STATUS))) { for_each_set_bit(bit, &imsi_status, MTK_MSI_IRQS_NUM) { - /* Clear the MSI */ - writel(1 << bit, port->base + PCIE_IMSI_STATUS); virq = irq_find_mapping(port->msi_domain, bit); generic_handle_irq(virq); + /* Clear the MSI */ + writel(1 << bit, port->base + PCIE_IMSI_STATUS); } } /* Clear MSI interrupt status */