From patchwork Thu Dec 21 02:11:16 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honghui Zhang X-Patchwork-Id: 10126905 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 E48AC60388 for ; Thu, 21 Dec 2017 02:11:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D47032918A for ; Thu, 21 Dec 2017 02:11:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C8EDC29A4B; Thu, 21 Dec 2017 02:11:42 +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 533782918A for ; Thu, 21 Dec 2017 02:11:42 +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:References:In-Reply-To: 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: List-Owner; bh=hP/KmryTsnVLzQ7eRS8+DUGYAHYitKudyFOgpV5Cb5Q=; b=WgxE7tC74p4ssT iNaQ1LMhd2MzqPIf0yyFH6pL0SSGLqvkKng9OuYp9UReQhYdABP8TE1VJENDUQXa18om+pDWT5S/s EoCnqHomON3KFPTbzwXspoHOdPH+KnezTwIf+arZFBXWhWsU+g/TPPtyuIQwHa7YiT3ApCVNNeU0A fnIQWRnKoYPShw7lnbiWF5a5N2IfhZs/gXSkNR+1y1E9M0miV00/XIWN97QkqsymOeJzXih7R06rj Ta67RWA3lM3jySBSCogGswAf7pMyJh15w2Yd8SoJMv0zHPDBczVigsa1ASadC5LsR4Trr01SIDUFp tc9/IFbZCurEUzpNFaxg==; 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 1eRqKi-0000Td-2b; Thu, 21 Dec 2017 02:11:40 +0000 Received: from [210.61.82.183] (helo=mailgw01.mediatek.com) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eRqKe-0000Qi-5a; Thu, 21 Dec 2017 02:11:38 +0000 X-UUID: b660eb6e6a8a4b70884b01be74306411-20171221 Received: from mtkexhb02.mediatek.inc [(172.21.101.103)] by mailgw01.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 588323479; Thu, 21 Dec 2017 10:11:21 +0800 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs01n2.mediatek.inc (172.21.101.79) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Thu, 21 Dec 2017 10:11:21 +0800 Received: from localhost.localdomain (10.17.3.153) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1210.3 via Frontend Transport; Thu, 21 Dec 2017 10:11:20 +0800 From: To: , , , , , , , , , , Subject: [PATCH v2 1/2] PCI: mediatek: Clear IRQ status after IRQ dispatched to avoid reentry Date: Thu, 21 Dec 2017 10:11:16 +0800 Message-ID: <1513822277-18329-2-git-send-email-honghui.zhang@mediatek.com> X-Mailer: git-send-email 2.6.4 In-Reply-To: <1513822277-18329-1-git-send-email-honghui.zhang@mediatek.com> References: <1513822277-18329-1-git-send-email-honghui.zhang@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171220_181136_365541_75DB2F3D X-CRM114-Status: GOOD ( 11.85 ) X-BeenThere: linux-arm-kernel@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, yt.shen@mediatek.com, yong.wu@mediatek.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=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 infinite 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 */